U.S. patent number 3,698,411 [Application Number 05/058,824] was granted by the patent office on 1972-10-17 for kelly foot valve.
This patent grant is currently assigned to Smith International, Inc.. Invention is credited to William R. Garrett.
United States Patent |
3,698,411 |
Garrett |
October 17, 1972 |
KELLY FOOT VALVE
Abstract
A valve assembly to be disposed between lower end of kelly and
upper end of drill string comprises a spring loaded upwardly
closing, pressure release, poppet valve, the poppet including an
upwardly opening check valve with a frangible closure for the
passage of well tools. A foraminous skirt on the downstream side of
the poppet provides a strainer for the drilling fluid. An annular
flange carried by the skirt engages and seals with the inside of
the valve housing to provide increased area subject to upstream
pressure when the poppet opens, the housing being ported to
atmosphere downstream of the flange and the skirt sealing with the
housing below the port to prevent loss of drilling fluid. The
spring is housed in the annulus formed between the skirt and
housing.
Inventors: |
Garrett; William R. (Midland,
TX) |
Assignee: |
Smith International, Inc.
(Midland, TX)
|
Family
ID: |
22019141 |
Appl.
No.: |
05/058,824 |
Filed: |
July 29, 1970 |
Current U.S.
Class: |
137/71; 137/536;
166/317; 137/493.1; 137/544; 166/325 |
Current CPC
Class: |
F16K
17/18 (20130101); E21B 21/106 (20130101); E21B
34/063 (20130101); Y10T 137/7923 (20150401); Y10T
137/1789 (20150401); Y10T 137/7772 (20150401); Y10T
137/794 (20150401) |
Current International
Class: |
E21B
34/06 (20060101); E21B 21/10 (20060101); E21B
21/00 (20060101); E21B 34/00 (20060101); F16K
17/18 (20060101); F16k 017/18 (); F16k
017/40 () |
Field of
Search: |
;166/224,225
;137/68,71,469,493.1,493.2,492.9,496,512.1,536,515-515.7,540 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nelson; M. Cary
Assistant Examiner: Gerard; Richard
Claims
I claim:
1. A kelly foot valve assembly comprising a tubular valve body, a
downwardly facing annular valve seat around the interior of the
valve body defining a first flow passage, a poppet adapted to
engage said seat from the lower side thereof and close said
passage, resilient means urging said poppet against said seat, said
poppet having a second flow passage therethrough, an upwardly
facing seat around the second flow passage, and a closure
engageable with said upwardly facing seat and said closure forming
an upwardly opening check valve controlling flow through said fluid
passage through said poppet, said poppet and said downwardly facing
seat and said resilient means providing a downwardly opening spring
loaded poppet valve controlling fluid flow through said first
passage, means limiting the upward travel of said check valve
closure away from said upwardly facing seat, said check valve
closure when away from said upwardly facing seat in the poppet to
the limit of upward travel of said check valve closure being out of
contact and uncooperative with any other means to limit flow
through said assembly, said closure including a central portion
that is frangible, the space in said assembly inside said tubular
valve body above said closure being clear of obstructions to the
passage of tools, whereby a bar can be lowered from above into
contact with said central portion to break it out and upon breaking
out of said central portion of the closure there is left a clear
path for tools through said flow passage through said poppet, said
closure including a steel ring into which is screwed a frangible
member adapted to be replaced when broken out, said frangible
member being cone shaped, flaring downwardly, whereby the strength
of said cone is increased with respect to resistance to fluid
pressure from above allowing the frangible member to be made of
thin material to facilitate breakout, and whereby fluid flow past
said closure when said poppet is open is less turbulent.
2. Assembly according to claim 1 wherein said frangible member
comprises a thin laminate including an inner core of brittle
aluminum.
3. A kelly foot valve assembly comprising a tubular valve body, a
downwardly facing annular valve seat around the interior of the
valve body defining a first flow passage, a poppet adapted to
engage said seat from the lower side thereof and close said
passage, resilient means urging said poppet against said seat, said
poppet having a second flow passage therethrough, an upwardly
facing seat around the second flow passage, and a closure
engageable with said upwardly facing seat from the upper side
thereof, said upwardly facing seat and said closure forming an
upwardly opening check valve controlling flow through said fluid
passage through said poppet, said poppet and said downwardly facing
seat and said resilient means providing a downwardly opening spring
loaded poppet valve controlling fluid flow through said first
passage, and means limiting the upward travel of said check valve
closure away from said upwardly facing seat, said check valve
closure when away from said upwardly facing seat in the poppet to
the limit of upward travel of said check valve closure being out of
contact and uncooperative with any other means to limit flow
through said assembly, said closure including a central portion
that is frangible, the space in said assembly inside said tubular
valve body above said closure being clear of obstructions to the
passage of tools, whereby a bar can be lowered from above into
contact with said central portion to break it out and upon breaking
out of said central portion of the closure there is left a clear
path for tools through said flow passage through said poppet,
including means around the inner periphery of the valve body below
said seat providing an annular seal surface of smaller diameter
than said inner periphery of the valve body, and a tubular skirt
depending from said poppet and extending to said seal surface when
said poppet is in sealing engagement with said seat, and slidable
therein in sealing engagement therewith when said poppet moves down
away from said seat, the outer periphery of said skirt being spaced
radially inwardly from said inner periphery of the valve body
leaving an annular space therebetween providing a third fluid
passage communicating with said first fluid passage when the poppet
is off its said seat, and port means in said skirt communicating
the fluid passage provided by said annular space with a fourth
fluid passage defined by the interior of said tubular skirt, the
inner diameter of said tubular skirt being as large as the outer
diameter of said frangible central portion of the check valve
closure whereby all tools that will pass through the remainder of
said check valve after said central portion is broken out can pass
downwardly through said fourth passage.
4. A kelly foot valve assembly comprising a tubular valve body, a
downwardly facing annular valve seat around the interior of the
valve body defining a first flow passage, a poppet adapted to
engage said seat from the lower side thereof and close said
passage, resilient means urging said poppet against said seat, said
poppet having a second flow passage therethrough, an upwardly
facing seat around the second flow passage, and a closure
engageable with said upwardly facing seat from the upper side
thereof, said upwardly facing seat and said closure forming an
upwardly opening check valve controlling flow through said fluid
passage through said poppet, said poppet and said downwardly facing
seat and said resilient means providing a downwardly opening spring
loaded poppet valve controlling fluid flow through said first
passage, said closure including a steel ring into which is screwed
a frangible member adapted to be replaced when broken out, said
frangible member comprising an inner core of brittle aluminum and
an outer layer of rubber carrying threads for engagement with said
closure.
5. Assembly according to claim 4 wherein said frangible member also
includes a rubber inner layer.
6. Assembly according to claim 5 wherein said closure is cone
shaped, flaring downwardly.
7. A kelly foot valve assembly comprising a tubular valve body, a
downwardly facing annular valve seat around the interior of the
valve body defining a first flow passage, a poppet adapted in a
closed position to engage said seat from the lower side thereof and
close said passage, means mounting said poppet for movement axially
of said valve body between said closed position and open positions
wherein said poppet is out of engagement with said seat, resilient
means urging said poppet against said seat, said poppet having a
second flow passage therethrough, an upwardly facing seat around
the second flow passage, and a closure engageable with said
upwardly facing seat from the upper side thereof, said upwardly
facing seat and said closure forming an upwardly opening check
valve controlling flow through said fluid passage through said
poppet, said poppet and said downwardly facing seat and said
resilient means providing a downwardly opening spring loaded poppet
valve controlling fluid flow through said first passage, means
around the inner periphery of the valve body below said seat
providing an annular seal surface of smaller diameter than said
inner periphery of the valve body, and a tubular skirt depending
from said poppet and extending to said seal surface when said
poppet is in sealing engagement with said seat, and slidable
therein in sealing engagement therewith when said poppet moves down
away from said seat, the outer periphery of said skirt being spaced
radially inwardly from said inner periphery of the valve body
leaving an annular space therebetween providing a third fluid
passage communicating with said first fluid passage when the poppet
is off its said seat, port means in said skirt communicating the
fluid passage provided by said annular space with a fourth fluid
passage defined by the interior of said tubular skirt, said port
means being fully open in all positions of said poppet, and an
annular flange carried by said skirt and making sliding sealing
engagement with the inner periphery of said body in said annular
space, said flange having an outer diameter greater than that of
the outer periphery of the area of contact between said poppet and
said downwardly facing seat.
8. Assembly according to claim 7 including port means in said valve
body communicating said annular space below said flange with the
exterior of said valve body.
9. Assembly according to claim 7 wherein said resilient means is a
helical spring disposed in said annular space and bearing at one
end against said flange and at the other end against said means
around the inner periphery of the valve body below said seal
providing an annular seal surface of smaller diameter than said
inner periphery.
10. Assembly according to claim 9 wherein said body has a threaded
box at the lower end thereof and the last said means comprises a
double pin sub having one pin screwed into said box, the last said
pin carrying an annular lip seal interiorly near the end thereof,
the other pin extending away from said box and providing means for
making connection with another threaded box.
11. Assembly according to claim 10 wherein said valve body has a
threaded box at its upper end and said annular valve seat comprises
a sub pin screwed into said box and having an annular conical
downwardly flaring surface at its lower end.
12. Assembly according to claim 7, said check valve closure also
having a tubular skirt depending therefrom extending telescopically
within the first said tubular skirt, and port means in the second
said tubular skirt providing for fluid flow through said second
flow passage when said check valve is open.
13. Assembly according to claim 12, said tubular skirts being
provided with interengageable means limiting upward telescopic
motion of the second said skirt relative to the first said skirt,
thereby limiting upward travel of said check valve closure away
from said upwardly facing seat.
14. Assembly according to claim 13, said check valve closure when
away from said upwardly facing seat in the poppet to the limit of
upward travel of said check valve closure being out of contact and
uncooperative with any other means to limit flow through said
assembly, said check valve closure including a central frangible
portion, the space in said assembly inside said tubular valve body
above said closure being clear of obstructions to the passage of
tools, whereby upon breaking out of said frangible portion of said
check valve closure there is left a clear path for tools through
said flow passage through said poppet.
15. A kelly foot valve assembly comprising a tubular valve body, a
downwardly facing annular valve seat around the interior of the
valve body defining a first flow passage, a poppet adapted to
engage said seat from the lower side thereof and close said
passage, resilient means urging said poppet against said seat, said
poppet having a second flow passage therethrough, an upwardly
facing seat around the second flow passage, and a closure
engageable with said upwardly facing seat from the upper side
thereof, said upwardly facing seat and said closure forming an
upwardly opening check valve controlling flow through said fluid
passage through said poppet, said poppet and said downwardly facing
seat and said resilient means providing a downwardly opening spring
loaded poppet valve controlling flow through said first passage,
means around the inner periphery of the valve body below said seat
providing an annular seal surface of smaller diameter than said
inner periphery of the valve body, a tubular skirt depending from
said poppet and extending to said seal surface when said support is
in sealing engagement with said seat, and slidable therein in
sealing engagement when said poppet moves down away from said seat,
the outer periphery of said skirt being spaced radially inwardly
from said inner periphery of the valve body leaving an annular
space therebetween providing a third fluid passage communicating
with said first fluid passage when the poppet is off its seat, port
means in said skirt communicating the fluid passage provided by
said annular space with a fourth fluid passage defined by the
interior of said tubular skirt, and foraminous means over said port
means providing a strainer for fluid flowing through said
assembly.
16. Assembly according to claim 15 wherein said foraminous means
comprises a perforate steel sleeve secured to said skirt over said
port means.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is the parent of a continuation application of the
same title Ser. No. 147,484, filed May 27, 1971 by the same
applicant as for the present application. The assignee of the
present application and said application Ser. No. 147,484 is also
the assignee of applications Ser. No. 58,825 filed July 29, 1970
and Ser. No. 147,964 filed May 28, 1971, both directed to subject
matter related to that of the present application. The latter
applications represent a prior conception upon which the present
invention is an improvement.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to valves and more particularly to a valve
assembly of the type known as a kelly foot valve used in the rotary
system of drilling oil wells.
Brief Description of the Prior Art
A gravity opened, stinger closed kelly foot valve is shown in U. S.
Pat. No. 3,191,905 to Brown. This construction is not adapted to
pass instruments and tools therethrough where required.
A full opening flapper gate type spring loaded pressure release,
kelly foot valve is shown in U. S. Pat. No. 3,289,691 to Kennard.
However flapper gate valves may not seal tightly.
A spring load poppet type pressure release kelly foot valve is
shown in U. S. Pat. No. 3,331,385 to Taylor. To allow for the
passage of tools the poppet includes a removable screw plug.
However the tool required for removing the plug may not always be
available.
A later U. S. Pat. No. 3,433,252 to Kennard shows a kelly foot
valve of the pressure and spring actuated rotary plug type. This
valve may be rather expensive to manufacture.
It has heretofore been proposed to incorporate in the seat of a
poppet type kelly foot valve such as that shown by Taylor an
upwardly opening ball check valve to pass fluid pressure upwardly
past the poppet valve at all times to show the existence of such
pressure prior to breaking the connection between the kelly and
drill pipe whereby the pressure can be relieved before the
connection is broken. The combination of an upwardly opening ball
check valve in the seat of a downwardly opening spring loaded
poppet type pressure release valve is shown in U. S. Pat. No.
2,749,992 to Hill. The proposed kelly foot valve incorporating a
Hill type valve construction to indicate the presence of drill
string pressure does not provide any means for passing instruments
or tools through the valve, possibly because the presence of the
ball check valve in the seat restricts the diameter of the
poppet.
Various means have been used to keep a spring loaded, kelly foot
valve open without the necessity of a pressure drop across the
valve equal to the force exerted by the bias spring. In the
aforementioned proposed kelly foot valve incorporating the Hill
type upwardly opening ball check valve in the seat of the
downwardly opening spring loaded poppet, it is proposed to seal off
the underside of the poppet from downstream pressure by allowing
the underside of the poppet to reciprocate in a cylinder sealed off
from the flow passage. In the Kennard rotary, ball plug, kelly foot
valve construction, it is not pressure differential across the
valve closure that compresses the bias spring; instead an annular
piston is geared to the ball and the upper piston head is exposed
to upstream pressure and the lower piston head is sealed off from
the fluid passage. In the Kennard flapper gate kelly foot valve
construction shown in his earlier patent a similar annular piston
drive is used, the piston being exposed to upstream pressure on one
side and to the pressure in a sealed chamber on the other side.
Such arrangements rely on the effectiveness of sliding seals to
prevent entrance of upstream pressure into the sealed chamber; if
the sealed chamber fills with mud the valve becomes inoperative,
remaining in the closed position permanently.
Alternative to the sealed chamber, the Taylor poppet type kelly
foot valve, and an alternative flapper gate type kelly foot valve
shown in the later Kennard patent, make use of the principle of
enlarging the valve opening area exposed to fluid pressure when the
valve opens. This is the same principle used in steam safety
valves. However in contrast to safety valves, which vent to
atmosphere, the additional areas exposed to line pressure when the
Taylor and Kennard valves open must rely for their effectiveness
upon the dynamic pressure differential between the upstream and
downstream sides of the added areas.
SUMMARY OF THE INVENTION
According to the invention the difficulties in the aforementioned
prior art and proposed constructions are eliminated by providing a
kelly foot valve assembly including a downwardly opening spring
loaded poppet valve with an upwardly opening, frangible closure,
check valve in the poppet, whereby when it is desired to lower
instruments or tools through the assembly the frangible check valve
closure can be broken out with a conventional wire line sinker bar,
always readily available, leaving a substantially full opening
through the assembly. A foraminous skirt carried by the poppet on
its lower side is spaced from the inner periphery of the valve body
downstream from the poppet and slidably seals at its lower end with
the inner periphery of a smaller diameter portion of the valve
body, whereby fluid passing the poppet is strained by the
foraminous skirt before passing into the outlet at the lower end of
the valve assembly. The skirt carries an annular flange which seals
with the inner periphery of the valve body below the poppet and
provides additional area subject to line pressure when the valve
opens, the opposite side of the flange being exposed to atmospheric
pressure by a vent through the valve body between the skirt seal
and the flange seal. The flange also provides a stop against which
bears one end of the bias spring, the spring being disposed inside
the valve body around the skirt and bearing at its other end
against the shoulder formed between the larger and smaller inner
diameter portions of the valve body.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1, 2 and 3 of the drawings together form a half section
through a kelly foot valve embodying the invention, the three
figures showing respectively the top, middle and bottom
thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings there is shown a kelly foot valve
assembly comprising an upper sub 10, same being a short length of
pipe having a fluid passage 11 therethrough and a threaded box 12
at its upper end for making connection with the lower end of a
kelly. The lower end of sub 10 is provided with a threaded pin 13
adapted for making connection with threaded box 20 at the upper end
of the tubular valve body 21. The lower end of the valve body is
provided with a threaded box 22 for making connection with threaded
pin 30 at the upper end of a lower sub 31. The lower end of sub 31
is provided with a threaded pin 32 adapted to make connection with
the threaded box at the upper end of a string of drill pipe. There
is a fluid passage 33 through lower sub 31 from one end to the
other.
Each of the pins and boxes heretofore described is provided with
sealing and torque transmitting shoulders as shown at 34, 35, 36,
37, 38, 39 whereby fluid tight connections are provided between the
kelly, the upper sub, valve body, lower sub and drill pipe in the
usual manner of rotary shouldered connections.
The pin 13 at the lower end of the upper sub is provided at its
lower end with a downwardly flaring conical seat 40. A poppet 41
has a seating surface 42 correlative to seat 40. A tubular skirt 43
depends from the lower end of poppet 41. There is an annular space
44 between the outer periphery of the skirt and the inner periphery
of the valve body below seat 40 providing a fluid passage
downstream of valve 41 from the fluid passage 11 in upper sub 12
thereabove. When the poppet 41 moves down away from seat 40,
opening the valve, fluid can flow from fluid passage 11 into fluid
passage 44.
Skirt 43 is slotted at one or more, e.g., four locations around its
circumference providing port means 45 for admitting fluid from the
annular fluid passage 44 in the valve body into the fluid passage
47 provided by the interior of skirt 43. Fluid passage 47
communicates with fluid passage 33 in the lower sub. An annular lip
seal 48 of elastomeric material provides a sliding seal between
skirt 43 and pin 30 as the skirt moves down and up during opening
and closing of the poppet valve.
A forminous steel sleeve 50 is disposed over the slotted portion of
the skirt, being received in reduced diameter section 51 and
secured in place by screws 52. The sleeve provides a strainer for
mud or other drilling fluid going through the assembly.
An annular flange 60 around skirt 43 is slidable in annular space
44 and carries an annular lip seal 61 of elastomeric material
adapted to make a sliding seal with the inner periphery of valve
body 21 as the poppet valve moves up and down between open and
closed position. A helical spring 62 in the portion of annular
space 44 below flange 60 and above the upper end 63 of pin 30 and
bearing against said flange and pin end with a predetermined force
due to initial compression tends to hold the poppet 41 closed
against seat 40. When the valve opens, e.g., due to upstream
pressure exerting a force on the poppet in excess of that of the
spring, the upstream fluid pressure is admitted to the space 44
above flange 60 and adds to the downward force tending to open the
valve. This counteracts the effect of upstream pressure being
admitted to the underside of the poppet inside the skirt and at the
lower end of the skirt when the valve opens. Therefore the valve
opens fully once it begins to open, analogous to a safety valve
used on a steam boiler. A port 65 in the wall of the valve body
communicates annular space 44 below the flange 60 with atmosphere
so that fluid leaking past flange 60 will not disable the
valve.
The poppet 41 is annular, providing a flow passage 70 therethrough
around the upper end of which is an upwardly flaring, conical seat
71. A closure 72 includes a ring 73 having a conical seating
surface 74 correlative to seat 71. An O-ring 67 in seating surface
74 insures a seal with the seat 71. A laminated
rubber-aluminum-rubber conical cap 75 completes the valve closure.
The cap includes an inner core 76 made of brittle aluminum and
outer thin rubber layers 77, 78 bonded to the core. The lower end
of the cap is provided with threads 79 in the rubber layer 77 which
engage threads 80 in ring 73. The closure 72 and seat 71 provide an
upwardly opening check valve. To limit upward opening of the check
valve closure and to guide the upward and downward movement of the
valve closure the closure ring 73 is provided with a downwardly
extending skirt 90. The skirt is vertically slotted at 91 for
cooperation with a pin 92 screwed into skirt 43.
In operation, during normal drilling the mud pumps will create
enough mud pressure in the kelly to open the poppet valve 41-40
against the force of spring 62 and the mud will then flow into
space 44 and act on flange 60 to hold the valve open. When it is
desired to add a length of drill pipe the mud pumps are shut down.
If there is still drill string pressure it will open the check
valve 72-71 in the poppet 41 and be transmitted through the kelly
to the mud pressure gage which will warn the operator to open the
bleed off valve until the fluid pressure has dropped to a safe
level. The lower sub 31 is then disconnected from the drill pipe.
The check valve 72-71 closes under gravity and the hydrostatic
pressure of the mud column in the kelly, thereby closing the
passage 70 through the poppet 41. The spring 62 exerts enough force
to hold the poppet against its seat 40 despite the hydrostatic
pressure of the mud column in the kelly. Therefore mud is retained
in the kelly rather than being spilled on the rig floor and the
operators. It is therefore apparent that a very efficient and safe
automatic mud saver valve assembly has been provided. Whenever it
is desired to lower an instrument or tool through the assembly, the
cap 75 can easily be broken out by lowering a sinker bar through
the kelly on a wire line and dropping it through the cap. The parts
of the cap are all made of easily drillable material so that no
problem results; furthermore the material is light and will float
out with the cuttings in the mud. A new cap 75 can easily be
screwed in to replace the one broken out. The cap is very
inexpensive.
The kelly foot valve assembly just described is preferably made of
steel except for the elastomer seals and the frangible closure.
While a preferred embodiment of the invention has been shown and
described, modifications can be made by one skilled in the art
without departing from the spirit of the invention.
* * * * *