U.S. patent number 3,917,230 [Application Number 05/220,284] was granted by the patent office on 1975-11-04 for well drilling control system.
This patent grant is currently assigned to Byron Jackson Inc.. Invention is credited to Charles D. Barron.
United States Patent |
3,917,230 |
Barron |
November 4, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Well drilling control system
Abstract
A well drilling control system in which the hoist mechanism
which supports the drill string and which is also employed to move
well bore and well head equipment between a floating barge and the
well bore and bottom of the sea, is controlled by load sensing and
movement sensing signalling transmitters to maintain a
predetermined weight on the drill bit during drilling operations
and to facilitate properly positioning, raising and lowering of
well bore and well head equipment, notwithstanding movement of the
floating barge vertically by wave action. A reverse drive mechanism
drives the hoist mechanism in a direction to allow downward
movement of the drill string, well bore or well head equipment when
the acceleration of the barge is so rapid that the supported weight
does not overcome the inertia of the drawworks.
Inventors: |
Barron; Charles D. (Fountain
Valley, CA) |
Assignee: |
Byron Jackson Inc. (Long Beach,
CA)
|
Family
ID: |
22822923 |
Appl.
No.: |
05/220,284 |
Filed: |
January 24, 1972 |
Current U.S.
Class: |
254/270; 175/27;
192/51; 254/274; 254/337; 254/340; 254/358; 254/367; 254/900;
254/903 |
Current CPC
Class: |
B66D
1/50 (20130101); E21B 19/09 (20130101); Y10S
254/903 (20130101); Y10S 254/90 (20130101) |
Current International
Class: |
E21B
19/00 (20060101); E21B 19/09 (20060101); B66D
1/28 (20060101); B66D 1/50 (20060101); B66D
001/48 () |
Field of
Search: |
;254/172,187,186,173
;175/27,5 ;192/51,87.13,87.16,43,3.27,3.22 ;166/.5 ;61/46.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Spar; Robert J.
Assistant Examiner: Noland; Kenneth
Attorney, Agent or Firm: Evans, Jr.; John O.
Claims
I claim:
1. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including an unidirectional source of power
and adjustable torque capacity continuously slipping drum clutch
means interposed between said source of power and said drum, the
line being unwound from said drum when the tension in the line
produces countertorque in said slipping drum clutch means that
exceeds its momentary torque capacity, additional reverse drive
means, including adjustable torque capacity continuously slipping
reverse clutch means, for driving said drum in a direction to play
out the line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
first slipping drive means including a source of power and
adjustable torque capacity slipping drive clutch means interposed
between said source of power and said drum, and said additional
reverse drive means including adjustable torque capacity slipping
reverse clutch means, and control means for increasing the torque
capacity of said reverse slipping clutch means when the torque
capacity of said slipping drum clutch means is reduced, said
control means including sensing means responsive to movement of
said equipment relative to said vessel, sensing means responsive to
movement of said vessel relative to the well, and means operable by
said sensing means to oppositely adjust the torque capacity of said
drum clutch means and said reverse clutch means.
2. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additonal reverse drive means, including
adjustable torque capacity continuously slipping reverse clutch
means, for driving said drum in a direction to play out the line
therefrom, and control means for increasing the torque capacity of
said slipping reverse clutch means when the torque capacity of said
first slipping drum clutch means is reduced, said first slipping
drive means including a source of power and adjustable torque
capacity slipping drum clutch means interposed between said source
of power and said drum, and said additional reverse drive means
including adjustable torque capacity slipping reverse clutch means,
and control means for increasing the torque capacity of said
reverse slipping clutch means when the torque capacity of said
slipping drum clutch means is reduced, said control means including
load sensing means responsive to the load of said equipment, and
means operable by said load sensing means to oppositely adjust the
torque capacity of said drum clutch means and said reverse clutch
means.
3. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, saiad
first slipping drive means including a source of power and
adjustable torque capacity slipping drum clutch means interposed
between said source of power and said drum, and said additional
reverse drive means including adjustable torque capacity slipping
reverse clutch means, and control means for increasing the torque
capacity of said reverse slipping clutch means when the torque
capacity of said slipping drum clutch means is reduced, said
control means including load sensing means responsive to the load
of said equipment, and means operable by said load sensing means to
oppositely adjust the torque capacity of said drum clutch means and
said reverse clutch means, and means for selectively rendering one
of said sensing means operative and the other inoperative.
4. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said control means including vessel position
sensing means and load position sensing means for producing
position signals determined by relative movement between the vessel
and the well and relative movement between the load and the vessel,
means responsive load position signals to produce a control signal,
and means responsive to said control signal for increasing and
decreasing the torque capacity of said slipping drive means as
aforesaid.
5. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said control means including vessel position
sensing means and load position sensing means for producing
position signals determined by relative movement between the vessel
and the well and relative movement between the load and the vessel,
means responsive load position signals to produce a control signal,
and means responsive to said control signal for increasing and
decreasing the torque capacity of said slipping drive means as
aforesaid, one of said position sensing means being operable in
response to a set point signal to modify the position signal to
vary said control signal and enable movement of the load in the
desired direction, and means for supplying a variable set point
signal to said one of said position sensing means.
6. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said control means including load sensing
means operable in response to the weight of the load to produce a
load control signal, means responsive to changes in said load
control signal to produce a control signal, and means responsive to
said control signals for increasing and decreasing the torque
capacity of said slipping drive means as aforesaid.
7. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said control means including load sensing
means operable in response to the weight of the load to produce a
load control signal, means responsive to changes in said load
control signal to produce a control signal, and means responsive to
said control signals for increasing and decreasing the torque
capacity of said slipping drive means as aforesaid, said means
responsive to said control signal being operable in response to a
set point signal to enable movement of the load in the desired
direction, and including means for supplying a variable set point
signal to said means responsive to said control signal.
8. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said control means including vessel position
sensing means and load position sensing means for producing
position signals determined by relative movement between the vessel
and the well and relative movement between the load and the vessel,
means responsive to said position signals to produce a position
control signal, load sensing means operable in response to the
weight of the load to produce a load control signal, and means
responsive to said control signals for increasing and decreasing
the torque capacity of said slipping drive means as aforesaid.
9. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said control means including vessel position
sensing means and load position sensing means for producing
position signals determined by relative movement between the vessel
and the well and relative movement between the load and the vessel,
means responsive to said position signals to produce a position
control signal, load sensing means operable in response to the
weight of the load to produce a load control signal, means
responsive to said control signals for increasing and dereasing the
torque capacity of said slipping drive means as aforesaid, and mode
selector means for rendering said means responsive to said control
signals operable, selectively, in response to said position control
signal and said load control signal.
10. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said slipping drive means comprising slip
clutches having air operated actuator means variable by said
control means for increasing and decreasing the torque capacity of
said slip clutches, saaid control means including vessel position
sensing means and load position sensing means for producing
position air signals determined by relative movement between the
vessel and the well and relative movement beween the load and the
vessel, means repsonsive to said position air signals to produce a
control air signal, and means responsive to said control air signal
for increasing and decreasing the air supplied to said actuator
means to vary the torque capacity of said slip clutches as
aforesaid.
11. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said slipping drive means comprising slip
clutches having air operated actuator means variable by said
control means for increasing and decreasing the torque capacity of
said slip clutches, said control means including vessel position
sensing means and load position sensing means for producing
position air signals determined by relative movement between the
vessel and the well and relative movement between the load and the
vessel, means repsonsive to said position air signals to produce a
control air signal, and means responsive to said control air signal
for increasing and decreasing the air supplied to said actuator
means to vary the torque capacity of said slip clutches as
aforesaid, one of said position sensing means being operable in
response to a set point air signal to modify the position air
signal to vary said control air signal and enable movement of the
load in the desired direction, and means for supplying a variable
set point air signal to said one of said position sensing
means.
12. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said slipping drive means comprising slip
clutches having actuator means variable by said control means for
increasing and decreasing the torque capacity of said slip
clutches, said control means including load sensing means operable
in response to the weight of the load to produce a load air signal,
means responsive to changes in said load air signal to produce a
control air signal, and means responsive to said control air signal
for increasing and decreasing the air supplied to said actuator
means to vary the torque capacity of said slip clutches as
aforesaid.
13. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a lod supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said slipping drive means comprising slip
clutches having actuator means variable by said control means for
increasing and decreasing the torque capacity of said clip
clutches, said control means including load sensing means operable
in response to the weight of the load to produce a load air signal,
means responsive to changes in said load air signal to produce a
control air signal, and means responsive to said control air signal
for increasing and decreasing the air supplied to said actuator
means to vary the torque capacity of said slip clutches as
aforesaid, said means responsove to said control air signal being
operable in response to a set point air signal to enable movement
of the load in the desired direction, and including means for
supplying a variable set point air signal to said means responsive
to said control air signal.
14. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound form said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said slipping drive means comprising slip
clutches having actuator means variable by said control means for
increasing and decreasing the torque capacity of said slip
clutches, said control means including vessel position sensing
means and load position sensing means for producing position air
signals determined by relative movement between the vessel and the
well and relative movement between the load and the vessel, means
responsive to said position air signals to produce a position
control air signal, load sensing means operable in response to the
weight of the load to produce a load control air signal, and means
responsive to said control air signals for increasing and
decreasing the air supplied to said actuator means to vary the
torque capacity of said slip cluthes as aforesaid.
15. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said slipping drive means comprising slip
clutches having actuator means variable by said control means for
increasing and decreasing the torque capacity of said slip
clutches, said control means including vessel position sensing
means and load position sensing means for producing position air
signals determined by relative movement between the vessel and the
well and relative movement between the load and the vessel, means
responsive to said position air signals to produce a position
control air signal, load sensing means operable in response to the
weight of the load to produce a load control air signal, means
responsive to said control air signals for increasing and
decreasing the air supplied to said actuator means to vary the
torque capacity of said slip clutches as aforesaid, and mode
selector means for rendering said means responsive to said control
air signals operable, selectively, in response to said position
control air signal and said load control air signal.
16. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and conrol means for increasing the torque capacity
of said slipping reverse clutch means when the torque capacity of
said first slipping drum clutch means is reduced, said control
means for increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and for decreasing the torque capacity of said
additional slipping drive means and increasing the torque capacity
of said first slipping drive means when the vessel moves downwardly
relative to the well, said control means including vessel position
sensing means and load position sensing means for producing
position signals determined by relative movement between the vessel
and the well and relative movement between the load and the vessel,
means responsive to said position signals to produce a control
signal, means responsive to said control signal for increasing and
decreasing the torque capacity of said slipping drive means as
aforesaid, and means responsive to the speed of rotation of said
drum to vary said control signal to prevent over-running of said
drum in opposite directions.
17. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said addtional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said control means including vessel position
sensing means and load position sensing means for producing
position signals determined by relative movement between the vessel
and the well and relative movement between the load and the vessel,
means responsive to the difference between said position signals to
produce a control signal, first controller means responsive to said
control signal and to said position signal from said load position
sensing means to maintain a predetermined torque capacity for said
first slipping drive means, and second controller means responsive
to said control signal and said position signal from said load
position sensing means to maintain a predetermined torque capacity
for said additional slipping drive means.
18. In apparatus for supporting and moving well equipment from a
floating vessel relative to the well, a drawworks including a fast
line drum for taking up and playing out a load supporting line,
first slipping drive means of variable torque capacity for driving
said drum in a direction to wind the line thereon, said first
slipping drive means including a unidirectional source of power and
adjustable torque capacity continuously slipping drum clutch means
interposed between said source of power and said drum, the line
being unwound from said drum when the tension in the line produces
countertorque in said slipping drum clutch means that exceeds its
momentary torque capacity, additional reverse drive means,
including adjustable torque capacity continuously slipping reverse
clutch means, for driving said drum in a direction to play out the
line therefrom, and control means for increasing the torque
capacity of said slipping reverse clutch means when the torque
capacity of said first slipping drum clutch means is reduced, said
control means increasing the torque capacity of said additional
slipping drive means and decreasing the torque capacity of said
first slipping drive means when the vessel moves upwardly relative
to the well and decreasing the torque capacity of said additional
slipping drive means and increasing the torque capacity of said
first slipping drive means when the vessel moves downwardly
relative to the well, said control means including load sensing
means for producing a load signal determined by the weight of the
load, first controller means responsive to said load signal for
producing a control signal determined by said load signal and a
set-point signal for maintaining a predetermined torque capacity
for said first slipping drive means, second controller means
responsive to said load signal and said set-point signal to
maintain a predetermined torque capacity for said additional
slipping drive means, and means for supplying said set-point signal
to said first and second controller means.
Description
BACKGROUND OF THE INVENTION
In recent years it has become common practice to drill wells into
the earth from floating or partially submerged barges or vessels
which are anchored or otherwise held in place at the surface of the
ocean or sea, at an offshore location. Such practice has involved
procedures which are different and equipment which is different
from the procedures and equipment used when drilling wells from a
stable platform or from a land-based derrick, due to the inherent
rise and fall of the vessel relative to the bottom of the sea or
ocean floor.
In part, the problems of relative vertical movement of the floating
vessel and the bottom of the sea or ocean floor have been
alleviated by the development of underwater well head equipment.
The use of such equipment involves setting a large casing or pipe
in place in the ocean floor and attaching to such pipe a blowout
preventer stack through which the well drilling string or pipe
extends during the drilling operations, the pipe extending upwardly
to the floating vessel or barge through the water. Thus, no
relative vertical movement can take place between the blowout
preventer and the well head, but the vessel and the drill string
may move vertically with the waves, relative to the blowout
preventer.
The problem of vertical movement of the drill string with the
floating vessel is a problem which has been attacked by the use of
bumper subs, which are specially constructed lengths of conduit
telescopically engaged to enable the transmission of rotary
movement to the drill bit from the drill string above the bumper
sub. Bumper subs, however, are expensive and are a source of other
problems such as leakage of drilling fluid and locking up so as to
be no longer extensible, or other failure, which may cause improper
drilling operations or shut down of the operations to enable repair
or replacement of the bumper sub.
Customarily, when wells, such as oil or gas wells, are being
drilled from a stable platform, say from a land-based derrick or a
derrick which is supported fixedly on the ocean floor, well
established drilling procedures are employed. In this connection,
the weight of the bit on the bottom of the well bore is established
by drill collars, which are heavy lengths of drill pipe located at
the lower end of the drill string. The string of drill pipe
extending upwardly from the drill collars to the kelly, which
slidably engages in the kelly bushing rotated by the rotary table
and is suspended by the hoist equipment in the derrick, may be many
thousands of feet in length. Stating the matter simply, then, the
total weight of the bit at the bottom of the well bore is the
difference between the weight of the length of drill pipe which is
supported in tension by the hoist equipment and the total weight of
the drill string. Thus, the heavy drill collars are located at the
lower end of the drill string and are relied upon to apply the
desired weight to the bit, as may be determined by the nature of
the subsuruface strata being drilled, both as to composition and
angle, the condition of the bit, and the direction that drilling is
progressing or is desired to progress. Such drill collars are also
quite rigid and resist flexure or bending and may be stabilized in
the well bore when desired.
Efficient drilling practice requires that the correct weight be
maintained on the bit to produce the maximum correct drilling
progress per unit of time. Control of the direction of drilling
progress requires control of the weight on the bit. Thus, the
weight on the bit should be fairly constant at a selected value, or
the bit will be caused to wear excessively or the drill string may
be deflected to an undesired angle, or drift from the desired
angle.
Vertical movement of a floating vessel on which the drilling
derrick and hoist equipment are mounted, however, causes vertical
movement of the drill string, which with the usual equipment will
cause changes in the weight of the bit, unless a bumper sub is
employed and is properly telescoping. However, the bumper sub does
not permit the weight on the bit to be changed, as may be required
to improve the penetration rate of the drill or to cause the
drilling direction to be changed or corrected, without round
tripping the drill string to modify the drill collar weight below
the bumper sub.
In addition, the vertical movement of the vessel or barge relative
to the ocean floor poses problems of controlling the lowering of
well head equipment, such as a blowout preventer stack, into
position at the ocean floor. Such problems are caused because the
vessel movement is superimposed on the motion of the equipment
being raised and/or lowered relative to the ocean floor by the
usual hoist equipment.
In the treatment and logging of wells during completion or
following completion, it sometimes becomes necessary to run into
the well auxiliary equipment which must be located fairly precisely
in the well bore and the position maintained during the treatment
or the equipment must be moved at a predetermined rate. Well
logging equipment, casing perforating devices, well packers and
formation testers are examples of such auxiliary equipment. In the
use of the logging, perforating and testing equipment, the position
must be maintained or known, but load or weight of the running in
string is not significant. Vertical movement of the floating vessel
renders difficult the effective application of the desired constant
tension or weight to the running in string or the maintenance of a
constant position of an auxiliary tool.
Efforts have been made to overcome such problems caused by the rise
and fall of a floating vessel from which well drilling, completion
and treating operations are performed by sensing the load of the
drill string or tension of the supporting cable for the drill
string and, in response to changes in load or line tension, varying
or controlling the torque applied to the cable winding drum of the
drawworks, in an effort to compensate for motion of the vessel in
opposite vertical directions relative to the bottom of the water.
However, such prior systems are relatively ineffective due to
substantial inertia problems.
The drill string composed of heavy pipe may be long and have
substantial weight and experience substantial friction in the well
bore, between the neutral point and the hoist mechanism, resulting
in the need for instantaneous sensing of changes in the vertical
position of the vessel and correspondingly rapid correction or
adjustment of the hoist mechanism, if the system is to be
effective. On the other hand, when lowering the subsurface well
head equipment, or raising the latter, and when drilling at shallow
depths, as well as when positioning treating or completing tools
within the well bore, the inertia of the supported load and the
hoist mechanism may be such that the rapid upward movement of the
vessel is not instantaneously compensated for.
SUMMARY OF THE INVENTION
The present invention involves the provision of hoist apparatus on
a floating vessel with hoist controlling means whereby to
compensate for vessel movement so that the load supported by the
hoist equipment, either the drill string, running in string, or
subsurface equipment being moved between the vessel and the ocean
floor, does not experience the motion of the floating vessel caused
by the rise and fall of the surface of the water.
The hoist mechanism of the typical drilling rig, including those on
floating barges or vessels, comprises a derrick at the top of which
is a crown block over which the fast line or working portion of a
cable is reaved, the cable being also reaved on a traveling block.
The working portion of the cable is taken up on and played out from
the drum of a drawworks and the dead end of the cable is suitably
anchored at the base of the derrick. The load, either the drilling
string, well head equipment, or tool running string, to be lowered
to the ocean floor or into the well bore is supported by a hook
suspended beneath or otherwise connected to the traveling block.
Thus, the present invention is directed towards controlling the
hoist cable system in such a manner that the hook does not
experience motion caused by vertical motion of the floating vessel,
but only that motion which is caused by or allowed by the hoist
system, so that the portion of the equipment supported by the hook
or the load or weight on a drilling bit may be controlled and
maintained constant.
In accordance with the present invention, the weight on the bit or
the load or tension on a running in string is maintained at a
selected, constant value by sensing the load on the hoist
mechanism. The position of well head or auxiliary equipment is
maintained by sensing the movement of the barge or vessel relative
to the stationary well site or riser pipe to produce signals which
may be compared with signals produced by movement of the block to
control the hoist equipment in such a manner that the movement of
the vessel caused by wave action is compensated for to maintain the
desired position or movement by compensating for vessel
movement.
Inasmuch as the mass of the drawworks, the hoisting block, hook,
drill string, or well bore or well head equipment is substantial,
the present invention provides a hoist control mechanism and system
which is capable of rapid response to changes in movement of the
vessel and/or load changes, as the case may be, notwithstanding the
substantial inertia of the system.
In addition, the invention provides a "down-drive" or reverse drive
for the drawworks, whereby to positively assist in playing line off
the drawworks drum, when the weight of the supported load would
otherwise be insufficient to overcome the inertia of the drawworks
and accelerate the latter to compensate for vessel movement.
In the practice of the invention, the drawworks drum is driven by a
slipping drive, the torque transmitting capacity of which, in a
selected automatic mode of operation, is varied in a manner
determined by the load supported by the hook, or by the position of
the hook or traveling block, relative to the barge or vessel,
vertical changes in the position of the barge or vessel with
respect to the sub-surface well pipe, and the speed and direction
of actual rotation of the drawworks drum on and from which the load
supporting fast line is wound and unwound. Also drivingly connected
with the drawworks drum is a slipping reverse drive controlled by
hook load or changes in the hook or barge position to drive the
drawworks drum reversely and overcome inertia when the barge or
vessel accelerates rapidly upwardly faster than the load can cause
acceleration of the drawworks drum.
The position sensing means preferably include position sensing
devices according to the application of U.S. patent Ser. No.
127,892, filed Mar. 25, 1971, such devices being adapted to produce
an output pneumatic signal which varies depending upon a change in
the position of a motion sensing drive member. To operate these
devices, sensing lines or cables are interconnected between both
the traveling block or hook and a take-up reel on the barge or
vessel, or other counterweight means, and a sensing line is
interconnected between a take-up reel on the barge or vessel or
other counterweight means, and a fixed location such as the well
pipe or riser beneath the water.
The slipping drive means for the drawworks drum preferably includes
in both the main slipping drive and the reverse slipping drive, a
clutch of the constantly slipping type shown in the application for
U.S. patent Ser. No. 19,601, filed Mar. 16, 1970, for Liquid Cooled
Clutch. The torque transmitting capacity of these slipping clutches
is varied as determined by signals produced by the position sensors
or the hook load sensor, or in a non-automatic mode, the clutches
may be manually controlled by conventional means.
This invention possesses many other advantages, and has other
purposes which may be made more clearly apparent from a
consideration of a form in which it may be embodied. This form is
shown in the drawings accompanying and forming part of the present
specification. It will now be described in detail, for the purpose
of illustrating the general principles of the invention; but it is
to be understood that such detailed description is not to be taken
in a limiting sense, since the scope of the invention is best
defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view generally showing a drilling rig on a vessel
afloat on a body of water and a well head at the bottom of the
water through which well drilling, testing, completion and treating
operations are conducted;
FIG. 2 is an enlarged diagrammatic view generally illustrating the
hoist and control mechanisms of FIG. 1;
FIG. 3 is a plan view illustrating the drawworks apparatus;
FIG. 4 is a view partly in elevation and partly in section, showing
a typical slip clutch for use in the main drum drive and the
reverse drum drive of the apparatus;
FIG. 5 is a longitudinal section, showing a typical line position
sensor for use in the control system to sense vertical movement of
the vessel relative to the well head equipment and to sense
movement of the traveling block relative to the vessel;
FIG. 6 is a longitudinal section, showing the computing pneumatic
relay which compares the position responsive signals from the
position sensors; and
FIGS. 7a through 7c, together constitute a schematic diagram of the
control system for the apparatus, FIGS. 7b and 7c being downward
continuations of FIG. 7a.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As seen in the drawings, with reference first to FIG. 1, the
present invention involves the apparatus useful in the drilling,
testing, completion and servicing of a well W which is being or has
been drilled into the earth through the ocean floor F. On the ocean
floor is well head equipment H through which the well drilling and
other operations are conducted, and extending from the well head,
upwardly towards the surface of the water is a so-called riser or
outer pipe R, as is customary.
The well drilling and other operations are conducted from a
floating barge or vessel V, or from a semi-submerged platform, as
is well known. On the barge or vessel V is a derrick D having a
crown block C over which extends a line or cable L constituting the
"fast-line" of the usual hoisting system, the line L being pulled
in or let out, as may be necessary, by means of a drawworks DW.
Supported by the line L is a combination of a traveling block and
hook T adapted to support a drill string or other pipe string S
which extends downwardly through the usual rotary table RT, through
the riser R and the well head equipment H into the well W.
The problem solved by the present invention involves relative
vertical motion between the vessel V and the well head H and
relative vertical motion between the traveling block and hook H,
and the combined vertical motion between the vessel V, the
traveling block and hook T and the well head H. During a well
drilling operation, to maintain a known constant weight on the bit,
the traveling block and hook T is lowered by the drawworks at a
rate determined by the rate of penetration of the drill bit through
the earth, under the control of the driller who observes the usual
weight indicator, but if waves or other water influences cause the
vertical motion of the vessel to be superimposed on the traveling
block and hook T, the drill string S will be correspondingly
reciprocated vertically and alternately reduce and increase the
weight on the drill bit, so that the drilling progress will be
erratic. Likewise, if vertical motion of the vessel V is
superimposed on the positioning of the traveling block and hook T,
when well treating or completing operations are being conducted
which require locating a sub-surface tool in the well, or when the
well head equipment H is being positioned in place, the proper
positioning of the tool or well head equipment will be
difficult.
Accordingly, the present invention involves controlling the
drawworks DW in such a manner as to compensate for the motion of
the vessel so that motion of the vessel is not superimposed on the
traveling block and hook T. When the weight of the pipe string S is
substantial, say when drilling, motion compensation is accomplished
by sensing the load on the traveling block and hook T and adjusting
the drawworks DW to take up or play out the line L as may be
necessary to maintain a substantially constant condition. When the
load on the traveling block and hook T is relatively light, say,
when running the well head H into position, when round-tripping
drill pipe, or when positioning a tool in the well W, motion
compensation is accomplished by sensing the position of the
traveling block T relative to the vessel V and sensing the position
of the vessel V relative to the well head H, and adjusting the
drawworks to take up or let out the line L as may be necessary to
maintain a substantially constant condition of position or rate of
movement of the traveling block T.
Since the drawworks machinery is massive, and since under some
conditions of load on the line L and motion of the vessel V, the
load cannot overcome the inertia of the drawworks sufficiently
rapidly to pull line L therefrom during upward movement of the
vessel V, the present invention involves, also, positively driving
the drawworks in a reverse direction when necessary, to overcome
inertia and reversely accelerate the motion of the line L at a rate
corresponding substantially to the rate of upward movement of the
vessel V.
Referring more particularly to FIG. 2, the apparatus will be seen
to comprise load sensing means LS for sensing the load on the
traveling block hook combination T. This load sensing means, in the
illustrative embodiment is incorporated in the crown block C, by
interposing a hydraulic load cell 1 between a lower fixed portion 2
and an upper movable portion 3 of the crown block support. The
traveling block movement is sensed by a sensing line 4, suitably
connected to the traveling block T and extending over a pulley 5
rotatably supported on the crown block support. This sensing line 4
is engaged with the traveling block movement sensing means TS,
later to be described in detail, which is located at a convenient
out-of-the-way location, the line 4 being wound on or unwound from
take-up reel means 6. This take-up reel means, without need for
further illustration or description, may be a simple spring rewound
reel adapted to maintain the line 4 taught for engagement with the
sensing means TS. Vertical movement of the vessel V relative to the
well head H is sensed by vessel movement sensing means VS,
corresponding to the sensing means TS, as will be later described.
This sensing means VS is operated by a sensing line 7 connected at
8 to a fixed location, specifically the riser pipe R which is a
fixed upward extension of the well head H. The sensing line 7
engages the vessel movement sensing means VS and is wound on and
unwound from take-up reel means 9 of the spring rewound type to
maintain the sensing line 7 taught. Adjacent to the drawworks DW in
a position convenient to the driller, is a control panel 10, from
which the apparatus can be controlled and monitored in the manner
hereinafter to be described, so that the drawworks, now to be
described, will be operated to pull in or play out the fast line L
under the control of the load sensing means LS or under the control
of the traveling block position sensing means and the vessel
position sensing means VS, and the related regulating system
hereinafter to be described, or under manual control.
Referring to FIG. 3, the drawworks DW is generally illustrated.
Since under some conditions, say while drilling a deep well, the
drawworks must support an extremely heavy string of drill pipe and
drill collars, and since, in the motion compensating mode of
operation, the entire load of the drill string or other load
supported by the traveling block and hook T must be accelerated
upwardly rapidly, the power system for the drawworks DW is
selectively operable to utilize more or less of a plurality of
prime movers or motors M. Electric motors M are preferred and are
suitably mounted on the floor of the derrick outwardly spaced from
the drawworks drum 11 with respect to the rotary table RT.
Without requiring illustration in detail of the various supporting
means, the drum 11, on which the fast line L is wound is fixed on a
rotatable shaft 12 on suitable bearings 13. At the opposite outer
ends of the drum shaft 12 are left and right hand slip clutches SC,
the details of which will be later described.
The slip clutches SC are adapted to drive the drum in a direction
to wind the line L on the drum or to allow the line to be played
off of the drum, depending upon the adjustment of the torque
transmitting capacity of the slip clutches. Drive means for the
slip clutch SC at the right hand side of the drum 11 include the
right hand three motors M which through the usual drive chains 14R
and sprockets drive a countershaft 15R. This countershaft 15R is
selectively drivingly connectable through chains 16R and sprockets
of different drive ratios to a right hand transmission shaft 17R,
the respective drive chains 16R and their sprockets on the
transmission shaft 17R being selectively coupled to the latter by
suitable clutches 18R, so that the transmission shaft 17R can be
driven at any of the three selective low, intermediate and high
ranges. The transmission shaft 17R drives a chain 20R which engages
the drive sprocket 21R of the right hand slip clutch SC to transmit
rotation through the clutch to the drum shaft 12.
Correspondingly, the left hand slip clutch SC is driven by the left
hand three motors M by means of left hand drive chains and
sprockets 14L, a left hand countershaft 15L, transmission chains
16L and companion transmission sprockets, connected to the
transmission shaft 17L by selective clutches 18L, to drive the
drive chain 20L for the left hand slip clutch sprocket 21L.
It will be understood, without requiring specific illustration,
that the right hand and left hand drives for the drum 11 can be
controlled and operated in unison, and that the transmission means
enable high speed drum rotation to low speed rotation at a range of
load capacity which will enable the drum L to hoist the substantial
weight encountered during the well drilling and other operations,
at a rate equal to the desired movement of the traveling block and
hook combination T, plus the vessel movement in a downward
direction, under the control of the slip clutches SC which drive
the drum and which are in turn adjusted, as required, by means of
this system and according to the method hereinafter described.
However, when the vessel V moves upwardly at a rapid rate, the
drawworks DW, as thus far described, must also allow the fast line
L to play off of the drum 11 at a rate equal to the desired motion
of combined traveling block and hook T, plus the movement of the
vessel. Even though the control system, later to be described, may
be capable of quickly controlling the slip clutches SC to minimize
the torque transmitting capacity of the clutches, so that the drum
11 is relatively free, the mass of the drum 11 in the usual
drawworks is so great that the inertia may not be overcome by the
supported load sufficiently rapidly to enable full compensation for
the vessel movement. The steeper the incline of an ocean wave and
the more rapid the rate of travel of the wave, the greater the
acceleration problem.
Accordingly, in accordance with the invention, the present
drawworks, also includes a reverse drive means RD for the drum 11,
whereby to overcome the inertia of the drum and accelerate it as
may be necessary, to fully compensate for the vessel movement
upwardly, so that such upward motion will not be superimposed on
the desired motion of the load supported by the traveling block and
hook T.
The reverse drive means RD, as specifically illustrated, is driven
by the right hand transmission shaft 17R, but, if preferred, may be
otherwise driven, say be a separate power source. Since the
transmission shaft 17R is shown as the input drive shaft, the
reverse drive DR has a reversing gear set 22 to drive a reverse
drive output shaft 23 oppositely from the shaft 17R. Driven by the
output shaft 23 is another slip clutch SC corresponding, in
general, with the clip clutches SC which drive the drum shaft 12,
but of smaller size, since the torque capacity of the reverse drive
means RD need not be as great as the torque capacity of the drum
drive. The output of the slip clutch SC of the reverse drive means
RD is connected by a drive chain 24 and companion sprockets to the
drum shaft 12 to drive the latter in the reverse direction when the
drum slip clutches SC are comparatively disengaged under the
control of the motion and load sensing means, later to be
described, but when the drum slip clutches SC are engaged to wind
in the fast line L, the slip clutch SC of the reverse drive means
is comparatively released.
Various slipping drives may be employed at the locations of the
respective slip clutch means, or otherwise, but preferably the
slipping drives comprise slip clutches SC in accordance with the
aforementioned application for patent, and a typical one of which
is shown in FIG. 4.
The clutch SC is associated with an end 33 of the drum shaft 12,
and the drive chain 20 engages the sprocket 21 which is revolvable
relative to the shaft end 33 on bearings 33a. Affixed to the
sprocket 21, is a disc 34 which is in turn affixed by fasteners 35
to the outer periphery of the back-up plate 36 of the slip clutch
means SC.
The slip clutch means SC includes an outer annular body 37 to which
an annular flange 38 is connected by fasteners 39 in opposed
relation to the plate 36. Internally thereof, the body 37 has a
splined connection 40 with the outer periphery of an axially
shiftable clutch pressure plate 41. Between the clutch plates 36
and 41 is a clutch friction disc 42 having friction facing 43 on
opposite sides thereof and having, as at 44, a splined connection
with a hub 45 which is disposed upon the shaft end 33 and is keyed
thereto by a key 46. Thus, rotation from the sprocket 21 will be
transmitted to the drum shaft 12 when the slip clutch means SC is
engaged to transmit rotation from the clutch body 37 and its plates
36 and 41 to the friction disc 42.
Engagement of the slip clutch means SC is accomplished by an
annular expansible actuator tube 47 having an air inlet 48. The
actuator tube 47 engages an annular body of insulating material 49
interposed between the tube 47 and the clutch pressure plate 41.
Each of the clutch plates 36 and 41 has a number of annular,
radially spaced and concentric coolant passages 36a and 41a to
which a coolant is supplied to dissipate the heat of friction
caused by slippage of the clutch SC. These passages 36a and 41a are
defined respectively between the clutch plates and a wear disc 36b
carried by the plate 36b and a wear disc 41b carried by the plate
41, the friction material on the friction disc 42 being engaged
with the wear discs 36b, 41b.
Such cooled, slip clutches are well known, and generally are
provided with a coolant circulating system including a stationary
coolant connector 51 through which coolant flows to and from a
rotary connector 52 which is connected, as by fasteners 52a, to the
clutch flange 38 and which has conduit means 53 for supplying
coolant to the passages 36a and 41a, as well as conduit means for
the return flow of coolant to the connector 51 and thence to a heat
exchanger. Preferably, in order to more effectively cool the
clutch, it is constructed in accordance with the aforementioned
application for patent. In addition, the rotary connector 52
provides a connection for air conduit means 54 which leads to the
air inlet 48 for the clutch actuator tube 47 from a stationary air
inlet fitting 55. As is well known, the torque transmitting
capacity of such slip clutches varies with the pressure of air in
the actuator tube 67.
Thus, the tension applied to the line L will be determined by the
magnitude of the air pressure supplied to the actuator tube 47
through the coupling 55 of the respective slip clutches under the
control of the system to be more fully described below.
The typical and preferred line position sensing means VS and TS is
shown in greater detail in FIG. 5. It comprises an elongated
housing 81 having at one end a closure or cap 82 and having at the
other end an assembly which provides an air inlet or supply port
84, an outlet 85 for a controlled air pressure signal, a port 86
for bias pressure fluid, and a port 87 communicating with the
atmosphere.
Included within the assembly are actuator means generally denoted
at 88, fluid pressure responsive piston means 89 operatively
connected to the actuator means 88, orifice means 90 operable in
response to the application of fluid pressure to the piston means
89 and to the application of force from the actuator means 88 for
opening and closing the orifice means 90, and combined inlet and
outlet valve means 91 for controlling the flow of air from the
supply port 84 to the outlet port 85 and for controlling the
exhaust of air from the outlet port 85 to the atmosphere through
the port 87.
In general, it is the purpose of the position sensing pneumatic
control device to regulate the output signal pressure to a constant
value which is determined by the net force applied to the piston
means 89, whereby the orifice means 90 is either opened or closed
for a period sufficient to balance the piston means 89, so that the
pressure drop through the orifice means 90 remains constant,
resultingn in a constant output signal pressure at the port 85
which leads to the computer relay or transmitter, as will be later
described.
More particularly, the actuator means 88 comprises a shaft 92 which
extends longitudinally of the housing 81 and has an end cap 82
through a suitable bearing 94 and a suitable seal 95. Disposed upon
the shaft 92 within the housing 81 is a spring seat 96 having a
reduced central section 97 on which is piloted the upper end of a
coiled compression spring 98. The shaft 92 is threaded as at 99,
and the spring seat 96 and the reduced pilot portion 97 thereof are
complementally threaded, whereby rotation of the shaft 92 will
effect longitudinal movement of the spring seat 96 on the shaft,
since the seat 96 is held against rotation by a key 100 carried
thereby and extending into a lateral slot 101 in the housing 81. At
its inner end, the spring 98 seats on a spring seat 103 having a
reduced pilot portion 104. This spring seat 103 is connected by
fasteners 105 to the circular upper body portion 106 of the piston
107 of the piston means 89, the seat 103 and the body 106 being
held in axially spaced relation by tubular spacers 108 interposed
therebetween and through the fasteners 105 extend. The lower end of
the shaft 92 extends through the seat 103 and is journalled in a
bearing 109 which is mounted in a supporting spider 110 having
circumferentially spaced openings 111 to accommodate the spacers
108, whereby the piston means 89 is axially movable.
The assembly also comprises, in addition to the spider 110, an
annular spacer 112, an annular cylinder 113 for the piston 107 and
an annular cylinder 114 which houses a piston 115, an annular body
116 containing the nozzle means 90, and an end member 117. The
spider 110, spacer 112, cylinders 113 and 114, annular body 116,
and end member 117 are interconnected together and to the
cylindrical body 81 by tie-bolts or the like, requiring no
illustration.
Between the spacer 112 and the cylinder 113 is clamped the outer
marginal portion of a diaphragm 119, and between the cylinder 113
and the cylinder 114 is clamped the outer marginal portion of
another diaphragm 120. Still another diaphragm 121 has its outer
marginal portion clamped between the cylinder 114 and the annular
body 116. In the illustrative embodiment, the upper body portion
106 of the piston 107, the piston 107 and the piston 115 are
interconnected by a stem 122 having an enlarged head 123 at one end
which clamps the inner periphery of the diaphragm 121 against the
adjacent portion of the piston 115, and a nut 124 is threaded onto
the other end of the stem 122 to effectively clamp the piston 107
and its upper body portion 106 together. The inner periphery of the
diaphragm 119 is like-wise clamped between the upper body portion
106 and the piston 107, and the inner periphery of the diaphragm
120 is clamped between the piston 107 and the piston 115. Thus, the
piston means 89 comprises both the piston 107 and the piston
115.
More particularly, the piston 107 has an enlarged portion 125 which
is exposed to the pressure in a chamber 126 provided in the
cylinder 113 between the diaphragms 119 and 120. The piston 115 is
exposed to the pressure in a chamber 127 provided in the annular
body 116 across substantially the entire cross-sectional area of
the piston 115. Within the cylinder 114, the piston 115 is disposed
in a chamber 128 which is vented to the atmosphere through radial
ports 129.
Interposed between the annular body 116 and the end member 117, and
clamped at its outer margin is a double diaphragm assembly
including an upper diaphragm 130 and a lower diaphragm 131 spaced
apart by an outer marginal spacer 132 in which is formed one or
more of the radial ports 87, previously referred to, which
communicate the space between the diaphragms 130 and 131 with the
atmosphere. In the annular body 116 above the upper diaphragm 130
is a chamber 134 and centrally of the body 116 is a threaded bore
having therein a nozzle 136 of the nozzle means 90, the port
through which communicates with the chamber 134, and the outlet of
which is opposed by a nozzle seat 137 suitably carried by the lower
end of the stem 122. Air is supplied to the chamber 134 and thence
to the nozzle 136 from the supply port 84 through a passage 138
which extends through the margin of the diaphragms 130 and 131 and
the spacer 132 and connects with a passage 139 leading into the
chamber 134. Disposed in the passage 139 is a flow restrictor 140
having a reduced passage therethrough. This flow restrictor is
replaceable through an opening in the body 116 which is closed by a
threaded closure plug 141. At the outer side of the diaphragm 131
in the end member 127 is a chamber 142 which communicates with the
outlet port 85. The outlet port 85 also communicates through a
passage 143 with the chamber 127 in the body 116 below the
diaphragm 121.
The inlet and outlet valve means 91, previously referred to,
includes a valve seat 144 carried by a plate 145 below the
diaphragm 131 and having a valve port 146 leading from the outlet
chamber 142 into the space between the diaphragms 130 and 131. A
coiled compression spring 145a is provided beneath the plate 145
which applies a normal inward bias to the diaphragm 131 and to the
outlet valve seat 144. A valve stem 147 is reciprocably mounted in
a port 147a in the end member 117, which port leads from the inlet
84 to the outlet 85. The stem is normally biased inwardly by a
coiled compression spring 148 which seats in a plug 149 in the end
member 117 and acts inwardly on a spherical valve head 150 to bias
the same against an inlet valve seat 151.
As previously indicated, the position sensing pneumatic control
device functions to regulate the output signal pressure at the port
85 to a value which is proportional to sensed movement.
Accordingly, the outer end 93 of the shaft 92, in the illustrative
embodiment, has mounted thereon the sheave or roller 152 which is
engaged by the sensing cable or line 4 or 7, of the sensing means
VS and TS, to effect rotation of the shaft 92 in response to
relative movement between such line 4 or 7 and the sensing unit.
The sheave or roller 152 is of such diameter that maximum line
motion will not cause rotation beyond the adjustment limits of the
screw shaft 92. Alternatively, a reduction gear means may be
employed to reduce the rotation of the shaft 92 per revolution of
the sheave 152. Movement of the sensing line is transmitted to the
shaft 92 to effect rotation of the latter in one direction or the
other depending upon the direction of movement of the line 4 or 7,
which depends on the direction of relative movement of the load and
the vessel. It is apparent that rotation of the shaft 92 in one
direction or the other will impose more or less compression on the
spring 98 to provide more or less force acting on the piston means
89 which will either cause the nozzle seat 137 to close the nozzle
136 or to open the nozzle 136 for communication with the chamber
127, and hence the discharge or signal output port 85. Such spring
force is opposed by the pressure of air in the chamber 127 acting
on the cross-sectional area of the piston 115 and the pressure of
fluid in the chamber 126 acting on the effective area of the piston
107. Thus, the fluid admitted through the port 86 to the chamber
126 may be supplied from a remote set point to modify operation of
the sensing unit so that the signal output pressure is at a desired
level, as will be later described, or the chamber 126 may be
exposed to atmosphere.
With the foregoing details in mind, the operation of the motion
sensor is such that the spring 98 is operative to apply a variable
force in a direction tending to move the piston means 89
downwardly. Opposing the force derived from the actuator means is
the force derived from the application of pressure either
atmospheric or from a remote set point to the bias chamber 126,
which pressure is effective over the area of the enlargement 125 of
the piston means 89 to provide a force tending to move the piston
means 89 upwardly. Also providing a force tending to move the
piston means 89 upwardly is the pressure in the piston chamber 127
which acts upon the piston 115 of the piston means 89, the other
side of the piston 115 being exposed to the atmosphere in the
chamber 128.
The effective signal outlet pressure in the piston chamber 127 is a
function of the inlet pressure and the passage of air from the
inlet 84 through the flow restrictor 140 into the pilot pressure
chamber 134 and the passage of air from the pilot pressure chamber
134 through the orifice means 136, as indicated by the arrows, into
the piston chamber 127. When the device is in the condition shown
in FIG. 5, the effective signal outlet pressure at the outlet 85 is
the same as that in the piston chamber 127, and under the condition
shown the pressure at the outlet 85 will remain constant, unless
the force derived from the actuator means 88 is varied, or the
force derived from the remote set point pressure is varied, as will
be later described.
Assuming that the force derived from the actuator means tending to
shift the piston means 89 downwardly is reduced, the net force
acting on the piston means will cause the piston means to move
upwardly, allowing greater flow from the pilot pressure chamber 134
into the piston chamber 127. Such action will result in an
instantaneous decrease in the pivot pressure in the chamber 134. As
a consequence, pressure applied to the diaphragm 131 and the force
of the spring 145a will move the exhaust valve seat 144 upwardly
away from the end of the valve stem 147, to allow the greater
exhaust of fluid pressure from the outlet chamber 142 and the
piston chamber 127 through exhaust port 87, until the device again
assumes the condition shown in FIG. 5 at which valve means 91 is at
equilibrium and the necessary volume of air is permitted to flow
through the port 146. At this time, the pressure at the outlet 85
will again be stabilized at a value determined by the fluid
pressures acting on the actuator means 88 and the decreased spring
force of the spring, and the signal outlet pressure will be at a
lower value.
Assuming that the force derived from the actuator means tending to
move the piston means 89 downwardly is increased, overcoming the
effect of the signal outlet pressure in the chamber 127, then the
orifice closure disc 137 will engage the end of the orifice means
136, thereby shutting off the passage of air from the pilot
pressure chamber 134 into the piston chamber 127. Under these
circumstances, the pilot pressure in the pilot chamber 134 will
build up, forcing the diaphragm 130 and the diaphragm 131
downwardly, thereby unseating the valve 150, so that inlet pressure
will transfer through port 147a of the inlet-outlet valve means 91,
resulting in an increase in the signal outlet pressure in the
outlet chamber 142 and in the piston chamber 127 which will be
effective to again condition the apparatus as shown in FIG. 5, so
that the pressure at the outlet 85 again remains constant, but
greater.
It will now be understood that variation of the remote set point
pressure in the chamber 126 will have the same effect as variation
of force derived from the actuator means. In other words, as the
remote set point pressure is increased, the force tending to move
the piston means 89 upwardly will also be increased, but if the
remote set point pressure is decreased, the force tending to move
the piston means 89 upwardly will be decreased.
The supply of air to the chamber 126 of the sensing unit of the
vessel or reference position sensing means VS, through the port 86
is shown in FIG. 7a, as being via a conduit 86a leading from a
suitable valve 86b which controls the pressure derived from a
source conduit 86c which leads from a suitable pressure source, not
shown. The outlet port 85 is in communication with a conduit 85a
which leads to a computer relay or pressure transmitter CR,
hereinafter to be described. On the other hand, the chamber 126 of
the sensing unit of the load position or traveling block position
sensing means TS, communicates with atmosphere through the port 86,
unless a bias pressure other than atmosphere pressure is desired to
modify the operation of the system. In any case, the outlet 85 of
this sensing unit is connected by a conduit 85b to a proportional
controller, later to be described, and to the computing relay or
transmitter CR.
The computer relay or transmitter CR is provided to compare the
position signals received from the position sensors VS and TS and
another signal representing drum speed, as will be later described,
to produce a resultant output control pressure signal. As seen in
FIG. 6, the computer relay CR comprises a support 200 adapted to be
mounted at a suitable location. Carried by the support 200 is an
end cup 201 having a marginal flange 202 for connecting the cup 201
with an assembly which comprises a stack of discs 203, 204, 205,
206 and 207 and a body 208, all connected at the outer peripheries
by a suitable number of tie bolts, one of which is shown at 209.
The disc 203 includes a rigid central section 203' and a flexible
annular diaphragm 203" supporting the central section. Each of the
discs 204, 205, 206 and 207 correspondingly comprises a rigid
central section 204' to 207' and an annular diaphragm 204"0 to
207". Intermediate, the discs 203 to 207 are annular, outer
peripheral spacers 210 and central spacers 211. The outer spacers
210 are connected in the assembly by the tie bolts 209. The central
spacers 211 are interconnected at the respective central sections
203' to 207' by a pin 212 having a head 213 at its lower end and a
nut 214 at its upper end for clamping the central disc sections and
central spacers together.
Air under pressure is supplied to the computer means CR above and
below the stack of diaphragms and between the diaphragms from
various sources, whereby to provide an output pressure signal which
is a function of the various input signals and the constant force
of an adjustable coiled spring K which is disposed in the cap 201
and seats, at one end, on a seat 215 above the disc section 203'
and, at the other end, on a spring seat 216 carried by an axially
shiftable adjuster pin 217. The pin 217 is shiftable by an adjuster
screw 218 threaded in a nut 219 which is suitably affixed to the
support 200. Below the disc 207 is another coiled spring K' which
seats at one end in a seat 208' and engages at its other end
beneath the disc section 207' in opposition to the spring K. Thus,
the spring K is adjustable to provide a selected force on the
stacked disc sections 203' to 207', determined by the relationship
between springs K and K'.
Air pressure is supplied to a chamber VS1 in the cup 201, from the
vessel reference position sensing means VS via conduit 85a, by
suitable means, such as an inlet fitting 220, to provide a downward
force on the effective piston area of the central section 203' of
disc 203. In order to increase the magnitude of the force derived
from air pressure supplied to the computer CR from this position
sensor means via conduit 85a, a branch conduit from conduit 85a
leads to a chamber VS2 defined between the diaphragms 203" and
204", say through a pressure inlet 221, so that such pressure also
acts downwardly on the effective annular piston area of the central
section 204' of the disc 204, which extends radially beyond the
spacer 211 thereabove.
Below the annular piston area of the disc section 204' is a chamber
TS having an inlet 222 to which pressure fluid is supplied, via
conduit 85b, at a value determined by the load or traveling block
position sensing means TS, the pressure in chamber TS acting
upwardly on the effective annular piston area of the disc section
204' in opposition to the downward force derived from pressure in
the chambers VS1 and VS2.
Between the discs 205 and 206 is defined a pressure chamber A to
which air is supplied through an inlet 223 via a conduit 223a, at a
pressure determined by the speed of rotation of the winch drum,
under the control of a speed responsive means, as will be
hereinafter described. The disc section 206' provides an annular
piston area projecting radially outwardly of the spacer 211
thereabove, this piston area being responsive to pressure in
chamber A to provide a downward force. Below the disc section 206'
is another chamber B exposed via a port 224 to atmosphere but to
which air may be supplied at some other pressure, if desired,
representing load on the line L. Such pressure acts upwardly on the
effective annular piston area of the disc section 206'.
Below the disc 207, and in the body 208, is a chamber X which
constitutes an output chamber communicating with an outlet port 225
via porting 226. The pressure in the chamber acts upwardly on the
lower disc section 207', and this pressure is derived from an inlet
conduit 227a connected to an inlet port 227, and under the control
of the computer CR, an output signal is transmitted to control the
system, as will be later described.
Interposed between the body 208 and an end member 228 having the
ports 225 and 227 therein, and clamped at its outer margin, is a
double diaphragm assembly 229 including an upper diaphragm 230 and
a lower diaphragm 231 spaced apart by an outer marginal spacer 232
in which is formed one or more radial outlet ports 232a, which
communicate the space between the diaphragms 230 and 231 with the
atmosphere. In the body 208 above the upper diaphragm 230 is a
threaded bore having therein a nozzle 236, the port through which
communicates with the chamber X, and the outlet of which is opposed
by a valve head 237 suitably carried by the lower end of the stem
212. Air is supplied to the chamber 234 and thence to the nozzle
236 from the supply port 227 through a passage 238 which extends
through the margin of the diaphragms 230 and 231 and the spacer 232
and connects with a passage 239 leading into the chamber 234.
Disposed in the passage 239 is a flow restrictor 240 having a
reduced passage therethrough. This flow restrictor is replaceable
through an opening in the body 208 which is closed by a threaded
closure plug 241. At the underside of diaphragm 231 in the end
member 228 is a chamber 242 which communicates with the output port
225. The output port 225 also communicates through the passage 225,
previously referred to, with the chamber X in the body 208 below
the piston or disc section 207'.
Inlet and outlet valve means are provided to control the admission
of fluid from the inlet 227 to the chamber 242 and the exhaust of
such fluid through the vent port 232a. This valve means includes a
valve seat 244 carried by a plate 245 below the diaphragm 231 and
having a valve port 246 leading from the outlet chamber 242 into
the space between the diaphragms 230 and 231. A coiled compression
spring 245a is provided beneath the plate 245 and applies a normal
upward bias to the diaphragm 231 and to the outlet valve seat 244.
A valve stem 247 is reciprocably mounted in a port 247a in the end
member 228, which port leads from the inlet 227 to the outlet
chamber 242. The stem is normally biased inwardly by a coiled
compression spring 248 which seats in a plug 249 in the end member
228 and acts inwardly on a spherical valve heat 250 to bias the
same against an inlet valve seat 251.
As previously indicated, the computer means CR functions to
regulate the output signal pressure at the port 225 to a value
which is proportional to the input signals from the sensing means
VS and TS, as well as the input signal representing speed of the
drum 11, and in addition, the computer may be adjusted to modify
the output pressure by varying either the effective constant force
of spring K or the reference set point pressure in the chamber B.
Thus, as will be understood, the output pressure in chamber X is
determined by the various pressures in the various chambers VS1,
VS2, TS, A and B, acting on the various piston areas of the discs
203 to 207. The equation may be stated:
X = VS1 + VS2 - TS + A - B + or - K,
where VS1 and VS2 are the pressure derived from the vessel position
sensing means VS tending to close the nozzle 236, TS is the
pressure derived from load position sensing means TS tending to
open the nozzle 236, A is the pressure derived from the speed of
the drum 11 tending to close the nozzle 236, B is the atmospheric
pressure tending to open the nozzle 236, and K is the spring
constant.
The effective signal outlet pressure in the outlet chamber 242 is a
function of the reduction in the inlet pressure caused by the
passage of air from the inlet 227 through the flow restrictor 240
into the pilot pressure chamber 234, and the reduction in pressure
resulting from the passage of air from the pilot pressure chamber
234 through the orifice means 236, as indicated by the arrows, into
the pressure chamber X. When the device is in the condition shown
in FIG. 6, the effective signal outlet pressure at the outlet 225
is the same as that in the chamber X, and, under the condition
shown, the pressure at the outlet 225 will remain constant, unless
the force derived from any of the position sensing means VS or TS,
drum speed, or the reference pressure at chamber B is varied, and,
accordingly, as will be later more fully described, the actuating
pressure supplied to the clutches SC which drive the drum 11 will
remain constant.
Assuming that the force tending to shift the stacked disc section
causes the valve head 237 to move upwardly allowing greater flow
from the pilot pressure chamber 234 into the chamber X, such action
will result in a decrease in the pilot pressure in the chamber 234.
As a consequence, pressure applied to the diaphragm 231 and the
force of the spring 245a will move the exhaust valve seat 244
upwardly and off of the end of the valve stem 247 to allow the
exhaust of fluid pressure from the outlet chamber 242 and the
chamber X through exhaust port 232a between the diaphragms 230 and
231, until the device again assumes the condition shown in FIG. 3
at which the exhaust valve port 246 is again closed. At this time,
the pressure at the outlet 225 will again be stabilized at a lower
value, determined by the change in forces acting on the stack of
disc sections 203' to 207'.
Assuming that the net force tending to move the stacked discs 203'
to 207' downwardly is increased, overcoming the effect of the
signal outlet pressure in the chamber X, then the orifice valve 237
will close the orifice means 236, thereby shutting off the passage
of air from the pilot pressure chamber 234 into the chamber X.
Under these circumstances, the pilot pressure in the pilot chamber
234 will build up, forcing the diaphragm 230 and the diaphragm 231
downwardly, thereby unseating the valve 250, so that inlet pressure
will transfer through port 247a of the inlet-outlet valve means,
resulting in an increase in the signal outlet pressure in the
outlet chamber 242 and in the chamber X, which will be effective to
again condition the apparatus as shown in FIG. 6, so that the
pressure at the outlet 225 again remains constant, but greater.
The controlling system of FIGS. 7a through 7c will now be
described. At this point, it will be understood that the pressure
in the chambers VS1 and VS2 of the computing relay CR is determined
not only by the position of the sensing line 7, resulting in the
transmitting of a pressure from the sensing unit of the vessel
portion sensing means VS to the chambers VS1 and VS2 related to
position sensing line movement, but also by the variable pressure
in chamber 126 of this sensing means VS supplied via conduit 86a,
resulting in more or less force applied to the piston means 89 to
oppose the force of the spring 88. Thus, by manipulating the supply
valve 86b, the outlet signal pressure supplied from the unit of the
position sensor VS, is adjusted to modify the outlet signal
pressure in the chamber X of the computing relay CR, so that the
signal supplied from the latter is varied to adjust the drum
clutches SC and move the load or allow the load to move relative to
the vessel V.
The output signal of the computer CR is also, as previously
indicated, variable by the speed of the rotation of the drum 11.
Thus, a pneumatic speed sensing transmitter device AS is driven by
the drum 11, and produces at an outlet conduit 223a a signal
derived from a source 223b, of a magnitude determined by winch
speed. Such pneumatic transmitters are well known and may be a
Foxboro Type 16A. Such output signal is applied through the conduit
223a to the inlet 223 of the computer CR and into chamber A.
A conduit 300 leads from the outlet port 225 of the computing relay
CR to the control pressure inlet 301 of a pressure controller PC,
of a conventional type, adapted to control the pneumatic pressure
at an outlet 302 supplied from a suitable source (not shown)
through an inlet 303, whereby, as will be later described, the slip
clutches SC which drive the drum 11 are adapted to apply a
controlled constant torque to the drum 11 which is a function of
the output signal pressure of the computer or transmitter means
CR.
More particularly, the controller PC may be Model 50 Controller of
Moore Products Co., of Spring House, Pennsylvania, or a Model 2516
Controller of Fisher Governer Company of Marshalltown, Iowa, as
examples, the controller, generally shown in FIG. 7b, being the
latter and more specifically illustrated in Bulletin D-2506A of
that company.
The controller PC is supplied a reference pressure at an inlet 304
from the conduit 85b connected to the outlet from the sensing unit
of the load or traveling block position sensing means TS, the same
reference pressure being supplied to the chamber TS of the computer
or transmitter means CR. The pressure signal from the chamber X of
the computer CR is admitted to a bellows 307 of the controller PC
which acts downwardly on a plate 308. Pressure supplied to the
inlet 304 from the load position sensing means TS causes an
increase in pressure in a bellows 309 which is opposed to the
bellows 307 and acts upwardly on the plate 308. The position of the
plate 308 relative to a nozzle 310, to which controlled fluid
pressure is supplied from the source inlet 303, is determined by
the difference in pressures in the bellows 307 and 309. If the
output pressure from the load position sensing means TS increases,
the pressure increases in bellows 309 causing the plate 308 to move
closer to the nozzle 310, restricting flow through the nozzle to
cause an increase in the pressure in a chamber 311 of a control
valve 312, causing an increased downward force on a diaphragm
assembly comprising spaced diaphragms 313 and 314, which carries a
valve seat 315, the passage through which communicates with the
atmosphere through a port 316 between the diaphragms 313 and 314.
The valve seat 315 engages and pushes downwardly, under the
circumstances now being described, on an inlet and outlet valve
having a head 317 for closing the exhaust passage through the valve
seat 315 and a head 318 which is moved away from a seat 319 to
allow increased supply pressure into the valve outlet chamber 230
which acts on the diaphragm 314 until the valve seat 315 is again
moved upwardly to allow return upward movement of the inlet-outlet
valve head 318 towards its seat.
During the same time that pressure is increasing in the chamber
320, such pressure is supplied to the outlet 302, and, thus, to the
clutches SC for the drum 11 via a conduit 325, as well as to an
adjustable proportioning valve 321, in the controller TC, and,
depending on the adjustment of the latter, to an adjustable re-set
control valve 322 which controls the build up of pressure in a
bellows 323. This bellows 323 acts downwardly on the plate 308
tending to move the latter away from the nozzle 310 to decrease
pressure at the outlet 302 and in control valve chamber 320, and is
opposed by the upward action of a bellows 324 to which pressure is
supplied from the valve 322 at a slower rate, depending on the
adjustment of the valve 322, until the plate 308 is moved toward
the nozzle to again increase pressure at the outlet 302 and in the
valve chamber 320.
If a change in the system causes a decrease in pressure at the
inlet 304 to the controller PC, then, the reverse action will occur
in the controller, the tendency being in either case to attempt to
return to a pre-established, constant pressure at the outlet 302,
which pressure is a function of the outlet pressure from chamber X
of the above-described computer means CR and the signal pressure
from the load position sensing means TS.
The outlet pressure from the controller means PC is supplied via
the conduit 325 to cause actuation of the clutches SC for the drum
11, but preferably a typical booster 326 is employed, whereby the
actual pressure source (not shown) for the clutches includes an
inlet to the booster 326 from a relatively high pressure source and
the pressure in conduit 325 acts on the usual pilot valve of the
booster, so that the outlet 328 of the booster is at a greater
pressure than the signal pressure from the controller PC. In
addition, it is preferred that a selector valve 329 be provided, so
that the air connector 55 of the clutches SC for the drum 11 may be
connected either to the booster outlet 328 or, alternatively, to a
separate source conduit 330 including a manual control valve 330a
for operating the clutches SC to drive the drum 11 independently of
the control system.
For convenience, a gauge panel G is preferably provided, as seen in
FIG. 7a, whereby to indicate the effective pressures determined by
the vessel motion sensing line and load position line sensing means
VS and TS, respectively, and the ultimate clutch actuating pressure
supplied to the slip clutches for the drum 11, such gauges being
designated by the legends "VES. POS.". "LOAD POS.", and "DRUM
CLUTCHES".
The "VES. POS." gauge is connected to the output of the position
sensing means VS by a conduit 400 which joins with the conduit 85a
leading to the computer chambers VS1 and VS2. The "LOAD POS." gauge
is connected by a conduit 401 to the conduit 85b which leads to
both the inlet 304 of the controller PC and to the chamber TS of
the computer or transmitter CR. The "DRUM CLUTCHES" gauge is
connected by a conduit 406 with the respective air inlet connectors
55 of the clutches SC for the drum 11 and the outlet 328 of the
pneumatic booster 326. Other gauges may be employed if desired to
show other pressures, such as the pressure derived from the speed
of the winch, and the bias pressure supplied to the sensing means
TS.
From the foregoing, it is clearly believed that the operation of
the present invention, as thus far described, involves the
controlling of the slip clutch drive means for the winch drum 11 to
apply a tension to the line L, controlled such that the tension is
maintained substantially constant at a value established by the
bias pressure supplied to the bias chamber 126 of the reference
position sensing means VS1, but the air pressure supply to the
clutches SC for the drum 11 is, in the automatic mode, controlled
by changes in load line 4 position or vessel line 7 position sensed
by the sensing means TS and VS, respectively, whereby, when the
vessel V moves relative to the well head H, a reference signal
proportional to the movement is supplied in the chambers VS1 and
VS2 of the computer CR, varying the output signal pressure in the
chamber X of the computer which is transmitted to the inlet 301 of
the proportional controller PC, which varies the actuating pressure
supplied to the actuators of the clutches SC for the drum 11, to
cause the load to move, thus operating the load position sensing
means TS until a change in the pressure supplied to chamber TS of
the computer CR equals the pressure change caused by movement of
the vessel position sensing means VS. Thus, the load is caused to
move substantially synchronously with the vessel V, unless the bias
pressure supplied to the chamber 126 of the vessel position sensing
means VS is varied at the valve 86b, to move the load in one
direction or the other relative to the vessel V, so long as the
weight of the load can overcome drawworks inertia when the vessel
moves upwardly.
The speed signal pressure transmitted to the chamber A of the
computer means CR is selected at some constant value when the winch
is stationary, and the speed responsive means AS produces an
increasing pressure signal as the velocity of the load increases
upwardly and a decreasing pressure signal as the velocity of the
load increases downwardly. During load movement, the transmitter AS
continuously supplies a changing pressure to the chamber A of the
computer CR, which changes the computer output signal to the
controller PC to assist in controlling overshooting the end points
of the load motion. In addition, the doubling of the effect of the
reference line position pressure signal supplied to the computer
means CR in a pair of chambers VS1 and VS2, causes the signal
supplied to the controller PC to be greater than would be the case
if the signal to the controller at the reference inlet 301 were
supplied directly from the sensing means TS.
It will also be understood, that if load control is desired, to
limit load on the drawworks, a load responsive signal may be
transmitted to the chamber B of the computer means CR to produce an
output signal which is determined by load on the line L adding a
force to the computer means CR supplementing the forces derived
from load movement.
In any event, when the load and motion conditions are such that the
line L should be pulled from the drum 11 at a rapid rate, the
system, as thus far described, will function to minimize the
pressure applied to engage the slip clutches SC for the drum 11. At
this time it is desired that the slip clutch SC of the reverse drum
drive means RD be forced into engagement to assist in overcoming
the drum inertia. To accomplish this function, a second
proportional controller PC2 is employed to produce an output
pressure for operating the slip clutch for the reverse drive means
RD which increases as the output pressure from the proportional
controller PC decreases.
This second controller PC2 is, in general, similar in structure and
functional characteristics to the controller PC. However, the
controller PC has the adjustable reset valve 322 which is not
necessary in the controller PC2, and its function is to produce a
reverse output signal as a function of the input signals from the
relay CR and the traveling block position sensing means TS, as
compared with the output from the controller PC.
More particularly, the controller PC2 may be a Moore Model 50X
proportional controller or a Fisher proportional controller, as
shown. In the schematic illustration of FIG. 7b, it will be seen
that the outlet conduit 300 from the computer CR has a branch 300'
connecting the outlet port 225 of the computing relay means CR to
the control pressure inlet 304', and the conduit 85b leading to the
controller PC from the position sensing means TS has a branch 85b'
leading to the inlet 301' of the controller PC2, whereby the
pneumatic pressure at the outlet 302' supplied from a source (not
shown) through an inlet 303', is determined by the inlet pressures
at the inlets 301' and 304' and is proportional to the output from
the computer CR and the load position sensing means TS, so that the
slip clutch SC of the reverse drive RD is adapted to apply a
controlled constant torque to the drum 11 which is a function of
the output signal pressure of the computer or transmitter means CR
and which increases as the output from the first controller PC
decreases, and vice-versa.
The pressure signal from the chamber X of the computer CR is
admitted to a bellows 309' of the controller PC2 which acts
upwardly on the plate 308'. Pressure supplied to the inlet 301'
from the load position sensing means TS causes a change in pressure
in a bellows 307' which is opposed to the bellows 309' and acts
downwardly on the plate 308'. The position of the plate 308'
relative to a nozzle 310' to which controlled fluid pressure is
supplied from the source inlet 303', is determined by the
difference in pressures in the bellows 307' and 309'. If the output
pressure from the load position sensing means TS increases, the
pressure increases in bellows 307' causing the plate 308' to move
from the nozzle 310', allowing greater flow through the nozzle to
cause a reduction in the pressure in a chamber 311' of a control
valve 312', causing a decreased downward force on a diaphragm
assembly comprising spaced diaphragms 313' and 314', which carries
a valve seat 315', the passage through which communicates with the
atmosphere through a port 316' between the diaphragms 313' and
314'. The valve seat 315' moves upwardly, under the circumstances
now being described, relative to an inlet and outlet valve having a
head 317' opening the exhaust passage through the valve seat 315'
and a head 318' which is moved toward a seat 319' to reduce supply
pressure into the valve outlet chamber 320' which acts on the
diaphragm 314' until the valve seat 315' is again moved downwardly
and causes downward movement of the inlet-outlet valve head 318'
relative to its seat.
During the same time that pressure is decreasing in the chamber
320', such pressure is supplied to the output 302', and, thus, to
the clutch SC for the reverse drive RD via a conduit 325', as well
as to an adjustable proportioning valve 321' and, depending on the
adjustment of the latter, a bellows 323'. This bellows 323' acts
downwardly on the plate 308' tending to move the latter away from
the nozzle 310' to decrease pressure at the outlet 302' and in
control valve chamber 320', and is opposed by the upward spring
action of a bellows 324' which is vented to atmosphere.
If a change in the system causes a decrease in pressure at the
inlet 304' to the controller PC2, then, the reverse action will
occur in this controller, the tendency being in either case to
return to a zero pressure at the outlet 302', which decreasing
pressure is a function of the outlet pressure from chamber X of the
above-described computer means CR and the signal pressure from the
load position sensing means TS which is in the reverse direction as
compared with the output pressure from controller PC.
The outlet pressure from the controller means PC2 is supplied via
the conduit 325' to cause actuation of the reverse drive clutch SC,
but preferably a typical volume and ratio booster 325' is employed,
whereby the pressure source (not shown) is connected to the inlet
to the booster 326' from a relatively high pressure source, and the
pressure in conduit 325' acts on the usual pilot valve of the
booster, so that the outlet 328' of the booster is at a greater
pressure than the signal pressure from the controller PC2. Between
the controller PC2 and the volume and ratio booster 326', a biasing
relay 362", such as a Moore model 680, is employed to amplify the
signal supplied to the volume and ratio booster.
The output from the reverse controller PC2 is supplied to the
reverse drive slip clutch SC through a mode selector valve means MS
which will be hereinafter more fully described, and in addition,
the controlled reverse clutch operating pressure from the
controller PC2 may be shutoff by a selector valve 329' and
operating pressure supplied to the booster 326' via a conduit 330'
under the control of a manual valve 330a.
It will now be understood, that when the selector valves 329 and
329' of the main drum clutch control system and the reverse clutch
control systems are in the positions to allow automatic control,
the clutches SC will be operated essentially in the following
manner.
The traveling block or load position sensing means TS produces a
reference signal representing relative motion of the load with
respepct to the well head H; while the vessel motion sensing means
VS produces a reference signal representing motion of the vessel V
relative to the well head H. These reference signals are compared
in the computer means CR, and also the drum speed signal is added
or substracted in the computer means CR, and an output signal is
produced which adjusts the controller PC and the controller PC2, so
that the pressure supply to the slip clutches SC for the drum 11
and the pressure supply for the slip clutch SC for the reverse
drive RD are proportionally and inversely varied. When the
drawworks machinery DW must be accelerated to compensate for
downward vessel motion, the pressure supplied to the slip clutches
SC for the drum 11 is increased to increase the torque transmitting
capacity and overcome inertia; and, at the same time, operating
pressure of the slip clutch SC for the reverse drive RD is reduced
to minimize resistance to rotation of the drum 11 in the normal,
load lifting direction. However, when the reverse vessel motion
occurs and the vessel is accelerating upwardly, the clutch
operating pressure supplied to the clutches SC for the drum 11 is
reduced as required to allow the load to remain in the same
position relative to the well head H, as line is pulled from the
drum 11. At the same time, there is a proportional increase in the
actuating pressure supplied to the slip clutch SC of the reverse
drive RD, so that the drum 11 is positively reversely driven,
overcoming the drum clutches SC and drum inertia, so that the line
L will be played off the drum 11 at the necessary rate to
compensate for upward vessel motion.
The foregoing control means is essentially position responsive,
i.e., the slip clutches SC for the drum 11 and the slip clutch SC
for the reverse drive RD are adjusted or maintained constant
depending upon relative movement between the load, the well head,
and the vessel. Therefore, the system, as thus far described, is
adapted to be utilized mainly during operations when the load is
relatively light, say, when round tripping a string of drill pipe,
shallow drilling, positioning tools in the well, lowering the well
head, etc.
The invention also contemplates a load responsive system, in which
the clutches SC are controlled in response to the load on the hoist
mechanism and sensed at the crown block C by the load sensing means
LS, including the load cell 1 which may be the well known type
adapted to produce a hydraulic pressure indicative of the applied
load or compression of the cell.
Here again, the purpose is to reversely drive the drum 11, but in
response to variations in the load applied to the load cell 1,
which controls the torque transmitting capacity of the slip
clutches SC.
Referring to FIG. 7c, it will be seen that the output from the load
cell 1 is conducted by a conduit 331 to a pneumatic controller or
transmitter C3 to control the output pressure at an outlet 332
derived from a source and applied at an inlet 333, so that the
output pressure is adjusted to a valve determined by the load
applied to the load cell 1.
Hydraulic pressure actuates a Bourdon tube 334 in the transmitter
or controller C3 to move a plate 335 towards or away from a nozzle
336. A valve assembly 337 has an outlet chamber 338 communicating
with the nozzle 336, and source pressure is supplied to the chamber
338 below a double diaphragm assembly including a diaphragm 339 and
a diaphragm 340. An outlet chamber 341 communicates through a valve
seat 342, which is carried by the diaphragms with an exhaust outlet
343 between the diaphragms 339 and 340, and a spring 344 normally
biases the seat 342 away from an inlet and outlet control valve 345
which is shiftable by the pressure in chamber 338 acting on the
diaphragm 339 and by the seat to a position allowing the flow of
air from a valve inlet chamber 346 into the valve outlet chamber.
On the other hand, if pressure in chamber 341 increases, the
diaphragm 340 moves the seat 342 downwardly to allow pressure to
discharge to atmosphere from the chamber 341 through the valve seat
342 and the exhaust port 343. Output pressure from chamber 341 of
the valve 337 is supplied through a variable proportioning valve
347 to an upper bellows 349 which acts downwardly on the beam 335,
and below the beam 335 is a bellows 350 acting upwardly and
supplied with a set point pressure at an inlet 351 through a
variable pressure regulator 352. Such controllers or transmitters
are well known, and the one illustrated is a Fisher Model 4151
transmitter, the purpose of which is to provide an output pressure
signal at the outlet 332 which is determined by the magnitude of
the load supported by the crown block C, and which signal is
applied to a proportional reset controller PC4 and to a
proportional controller PC5. The controller PC4 maintains an output
pressure for operating or engaging the main drum clutches SC, while
the controller PC5 maintains an output pressure for operating the
clutch SC of the reverse drive RD, whereby the respective drum
clutches and reverse drive clutch are reversely operated to
compensate for vessel motion in response to the load on the crown
block C.
The proportional reset controller PC4 is the same as the
aforementioned proportional reset controller PC, and, therefore,
the same reference characters are applied and its mode of operation
will be understood from the description above. Likewise, the
proportional controller PC5 is the same as the proportional
controller PC2, and, therefore, the same reference characters are
applied and its mode of operation will be understood from the
description above.
In the present case, however, the input to the inlet 301 of the
controller PC4 is from a manually operable set point regulator
valve 400a, and the input to the inlet 304 is from the load
responsive controller or transmitter PC3. Thus, the output from the
controller PC5 is determined by the relationship of the load
responsive input signal and a set-point pressure which is variable
by the driller to effect the desired load motion, up or down, and
the variable set-point pressure may be observed on a "LOAD REF."
gauge. When the input signal from the load responsive controller
PC3 increases, the output pressure from the controller PC4 will
increase and be maintained constant, and vice-versa. The output
from the outlet 302 of the controller PC4 is supplied to a volume
and ratio booster 401a which determines the pressure applied to the
main or drum clutches SC from the source inlet to the booster.
To control the reverse clutch SC for the reverse drive RD, the
input signals to the proportional controller PC5 are reversed, as
compared with the controller PC4. More particularly the load signal
from the transmitter PC3 is applied to the inlet 301' of the
controller PC5 and the set point pressure from the regulator 400a
is applied to the inlet 304', so that the pressure at the outlet
302' of the controller PC5 is also determined by the relationship
between the load pressure signal from the transmitter PC3 and the
set point pressure, but reversely proportional, as compared with
the output from the controller PC4. Thus, the output from the
reverse clutch controller PC5 will decrease when the output from
the controller PC4 increases, and vice-versa, so that when the main
or drum clutches SC are released, the reverse drive clutch SC will
be more tightly engaged. To amplify the output signal from the
controller PC5, it is connected to a pneumatic relay 402a and a
volume and ratio booster 403a which controls the source pressure to
the reverse slip clutch.
The output from the boosters 401a and 403a are connected to the
respective slip clutches SC, respectively, through the
above-mentioned mode selector valve MS, which is operable to
selectively connect the position sensing control system of FIGS. 7a
and 7b, or the load sensing control system of FIG. 7c to the
clutches SC. Moreover, if desired, the mode selector valve could
also incorporate another position for manual operation in lieu of
the separate selector valves 329 and 329', previously described. It
will also be understood, that if desired or necessary, the set
point pressure applied to the controllers PC4 and PC5 may be varied
by utilizing a computer, such as the relay CR to compute load
motion and drum rotation to establish a variable input signal to
the controllers PC4 and PC5.
* * * * *