U.S. patent application number 14/158314 was filed with the patent office on 2015-07-23 for pump system having speed-based control.
This patent application is currently assigned to Caterpillar Inc.. The applicant listed for this patent is Caterpillar Inc.. Invention is credited to Rodney Dale HARMS, Trevor IUND, Lucas Jason PETERSON, Don Miles WILBUR, JR..
Application Number | 20150204322 14/158314 |
Document ID | / |
Family ID | 53543423 |
Filed Date | 2015-07-23 |
United States Patent
Application |
20150204322 |
Kind Code |
A1 |
IUND; Trevor ; et
al. |
July 23, 2015 |
PUMP SYSTEM HAVING SPEED-BASED CONTROL
Abstract
A pump system is disclosed. The pump system may have a power
source, a pump, and a torque converter configured to fluidly couple
an output rotation of the power source to an input rotation of the
pump. The pump system may also have a sensor configured to generate
a signal indicative of an output flow rate of the pump, and a
controller in communication with the sensor and the power source.
The controller may be configured to selectively adjust a speed of
the power source based on the signal.
Inventors: |
IUND; Trevor; (Peoria,
IL) ; HARMS; Rodney Dale; (Bartonville, IL) ;
PETERSON; Lucas Jason; (Washington, IL) ; WILBUR,
JR.; Don Miles; (Manito, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Caterpillar Inc. |
Peoria |
IL |
US |
|
|
Assignee: |
Caterpillar Inc.
Peoria
IL
|
Family ID: |
53543423 |
Appl. No.: |
14/158314 |
Filed: |
January 17, 2014 |
Current U.S.
Class: |
175/48 ; 417/15;
417/20; 417/22; 417/42; 417/43 |
Current CPC
Class: |
F04B 49/065 20130101;
F04B 2205/09 20130101; F04D 15/0088 20130101; E21B 7/00 20130101;
F04B 49/20 20130101; F04D 15/0066 20130101; F04B 2203/0209
20130101; F04B 15/02 20130101; F04D 7/04 20130101; F04D 15/0094
20130101 |
International
Class: |
F04B 49/20 20060101
F04B049/20; E21B 7/00 20060101 E21B007/00 |
Claims
1. A pump system, comprising: a power source; a pump; a torque
converter configured to fluidly couple an output rotation of the
power source to an input rotation of the pump; a sensor configured
to generate a signal indicative of an output flow rate of the pump;
and a controller in communication with the sensor and the power
source, the controller being configured to selectively adjust a
speed of the power source based on the signal.
2. The pump system of claim 1, wherein: the power source is an
engine; and the controller is configured to selectively adjust the
speed of the power source by adjusting fueling of the engine.
3. The pump system of claim 2, wherein the controller includes a
table stored in memory relating the output flow rate of the pump to
a speed of the engine.
4. The pump system of claim 1, further including a mechanical gear
box connected between the torque converter and the pump.
5. The pump system of claim 4, wherein the mechanical gear box
includes a plurality of selectable gear combinations.
6. The pump system of claim 5, wherein each of the plurality of
manually selectable gear combinations creates an input-to-output
speed ratio of 7:1 or less.
7. The pump system of claim 6, wherein the controller is configured
to selectively adjust the speed of the power source to maintain a
pump output flow rate of about 10-20 gallons per minute.
8. The pump system of claim 1, further including an input device
configured to manually receive from an operator a desired pump flow
rate, wherein the controller is configured to selectively adjust
the speed of the power source based further on the desired pump
flow rate.
9. The pump system of claim 1, wherein; the torque converter
includes a lockable clutch; and the controller is configured to
selectively cause the lockable clutch to engage and mechanically
connect the output rotation of the power source to the input
rotation of the pump.
10. The pump system of claim 9, further including an input device
configured to manually receive from an operator an indication of a
desire to engage the lockable clutch, wherein the controller is
configured to selectively cause the lockable clutch to engage based
on the indication.
11. The pump system of claim 1, wherein the pump is a positive
displacement plunger pump.
12. The pump system of claim 1, wherein the sensor is a speed
sensor associated with one of the transmission and the pump.
13. A pump system, comprising: an engine; a positive displacement
plunger pump; a gear box mechanically connected to an input of the
positive displacement plunger pump and having a plurality of
manually selectable gear combinations; a torque converter fluidly
connecting an output of the engine to an input of the gear box; a
sensor configured to generate a speed signal associated with one of
the positive displacement plunger pump and the gear box; an input
device configured to receive from an operator a desired pump output
flow rate; and a controller in communication with the engine, the
sensor, and the input device, the controller being configured to
selectively adjust operation of the engine based on the speed
signal and the desired pump output flow rate.
14. A method of controlling a system having a power source fluidly
coupled to a pump, comprising: sensing a parameter indicative of an
actual output flow rate of the pump; and selectively adjusting a
speed of the power source based on the parameter.
15. The method of claim 14, wherein: the power source is an engine;
and selectively adjusting the speed of the power source includes
selectively adjusting fueling of the engine.
16. The method of claim 14, wherein selectively adjusting the speed
of the power source includes selectively adjusting the speed of the
power source to maintain an actual output flow rate of about 10-20
gallons per minute.
17. The method of claim 14, further including receiving manual
input from an operator indicative of a desired output flow rate,
wherein selectively adjusting the speed of the power source
includes selectively adjusting the speed based on the parameter and
the desired output flow rate.
18. The method of claim 17, further including referencing the
parameter and the desired output flow rate with a lookup table
stored in memory to determine a corresponding power speed
adjustment that reduces an error between the actual output flow
rate and the desired output flow rate.
19. The method of claim 14, wherein: the system also includes a
lockup clutch; and the method further includes: receiving manual
input from an operator indicative of a desire to mechanically lock
an output of the power source to an input of the pump; and
selectively engaging the lockup clutch based on the manual
input.
20. The method of claim 14, wherein sensing the parameter
indicative of the actual output flow rate of the pump includes
sensing an input speed of the pump.
21. A method of forming a well with a power source fluidly coupled
to a well-forming device, comprising: sensing a parameter
indicative of an actual output of the well-forming device; and
selectively adjusting a speed of the power source based on the
parameter.
22. The method of claim 21, wherein the well-forming device is one
of a slurry pump, a fracking pump, and a drill.
23. The method of claim 22, wherein the power source is an engine,
and selectively adjusting the speed of the power source includes
adjusting fueling of the engine.
Description
TECHNICAL FIELD
[0001] The present disclosure is directed to a pump system and,
more particularly, to a pump system having speed-based control.
BACKGROUND
[0002] A slurry pump increases the pressure of a liquid/solid
particulate mixture, and converts potential energy associated with
the increased pressure into kinetic energy. Slurry pumps are widely
used to transport raw minerals and ore (e.g., coal, sand, oil,
etc.), waste material (e.g., sewage), and refined products (e.g.,
cement). Different types of slurry include positive displacement
plunger pumps, centrifugal pumps, a lobe pump, or a peristaltic
hose pump.
[0003] A conventional slurry pump system includes a power source
(e.g., an engine or electric motor) connected through a gear box to
a pump. The gear box typically includes a single gear ratio of
about 7:1 or higher. In some applications, multiple different gear
ratios are available. The gear box provides a direct mechanical
connection from the power source to the pump. In these
configurations, the power source is typically operated at a
constant speed to provide a single flow rate of slurry from the
pump for each available gear ratio.
[0004] One problem with a conventional slurry pump system involves
flow rate consistency. In particular, as a load on the pump changes
due to changing conditions at an associated well or mine (e.g., due
to a density change or plugged hose), the flow rate of slurry from
the pump will likewise fluctuate. In some applications, this
fluctuation is undesired.
[0005] An attempt to address fluctuations in pump flow rate is
described in. U.S. Pat. No. 6,033,187 that issued to Addie on Mar.
7, 2000 ("the '187 patent"). Specifically, the '187 patent
discloses a way to determine an instantaneous pressure produced by
a slurry pump. Using this pressure, along with an overall total
pipeline resistance, an optimal operating speed of the pump may
then be determined. This speed may then be controlled, for example
by changing the output ratio of the gear box (if available), to
improve stability of the pumping system.
[0006] Although the system of the '187 patent may be adequate for
some applications, it may also suffer from drawbacks, In
particular, it may be difficult and time consuming (or not even
possible) to change the output ratio of the gear box. In addition,
this change may only provide step-wise adjustment in pump speed,
which may lack fine control necessary for some operations. Further,
the gear box required to provide the desired ratio(s) may be large,
heavy, and expensive,
[0007] The disclosed pump system of the present disclosure is
directed at solving one or more of the problems set forth above
and/or other problems in the art
SUMMARY
[0008] In one aspect, the present disclosure is directed to a pump
system. The pump system may include a power source, a pump, and a
torque converter configured to fluidly couple an output rotation of
the power source to an input rotation of the pump. The pump system
may also include a sensor configured to generate a signal
indicative of an output flow rate of the pump, and a controller in
communication with the sensor and the power source. The controller
may he configured to selectively adjust a speed of the power source
based on the signal.
[0009] in another aspect, the present disclosure is directed to a
method of controlling a system having a power source fluidly
coupled to a pump. The method may include sensing a parameter
indicative of an actual output flow rate of the pump. The method
may also include selectively adjusting a speed of the power source
based on the parameter.
[0010] In yet another aspect, the present disclosure is directed to
a method of forming a well with a power source fluidly coupled to a
well-forming device. The method may include sensing a parameter
indicative of an actual output of the well-forming device. The
method may further include selectively adjusting a speed of the
power source based on the parameter.
BRIEF DESCRIPTION OF THE DRAWING
[0011] FIG. 1 is a schematic illustration of an exemplary disclosed
pumping system.
DETAILED DESCRIPTION
[0012] FIG. 1 illustrates an exemplary disclosed pumping system 10.
Pumping system 10 may include, among other things, a power source
12 operatively connected to a pump 14 by way of a torque converter
16 and a gear box 18. Power source 12 may he configured to generate
a rotational power output. Torque converter 16 may he configured to
transfer at least a portion of the power output to gear box 18.
Gear box 18 may convert the rotation received from torque converter
16 to a rotation having a different speed and torque, and deliver
the converted rotation as an input to drive pump 14.
[0013] Power source 12 may produce a rotational output having both
speed and torque components, and may embody an internal combustion
engine. For example, power source 12 may he a diesel engine, a
gasoline engine, a gaseous fuel-powered engine, or any other engine
apparent to one skilled in the art. Power source 12 may contain an
engine block having a plurality of cylinders (not shown),
reciprocating pistons disposed within the cylinders (not shown),
and a crankshaft operatively connected to the pistons (not shown).
The internal combustion engine may use a combustion cycle to
convert potential energy (usually in chemical form) within the
cylinders to a rotational output of the crankshaft, which may in
turn rotate an input of torque converter 16.
[0014] Torque converter 16 may be used to transmit power from the
crankshaft of power source 12 into gear box 18. In the disclosed
embodiment, torque converter 16 is a hydro-mechanical device that
allows the crankshaft of power source 12 to rotate somewhat
independently of an input shaft of gear box 18. In this example,
torque converter 16 includes an impeller (not shown) fixedly
connected to the crankshaft of power source 12, and a turbine (not
shown) fixedly connected to the input shaft of gear box 18. The
impeller may be fluidly coupled with the turbine, such that as the
impeller rotates, a pressurized flow of fluid may be generated and
directed through the turbine, driving the turbine to also rotate.
At low fluid flow rates and pressures (or when pump 14 is heavily
and/or suddenly loaded), the impeller may rotate at a higher speed
relative to the turbine. However, as the pressure and the flow rate
of the fluid conducted between the impeller and turbine increases
(or when pump 14 is lightly loaded), the rotational speed of the
turbine may approach the rotational speed of the impeller. This may
allow power source 12 to rotate at a different speed and torque
than gear box 18, depending on operating conditions, with the
difference in speed and torque being accounted for by shearing
losses (i.e., heat) within the fluid.
[0015] It is contemplated that torque converter 16 could
alternatively be another type of fluidic or non-fluidic coupling,
if desired. For example, torque converter 16 could include friction
plates coupled to the crankshaft and gear box shaft. The friction
plates would be configured to slidingly and rotationally engage
each other, and thereby transfer a percentage of the power
generated by power source 12 into gear box 18. Other configurations
of torque converter 16 may also be possible.
[0016] In some embodiments, torque converter 16 may also include a
lockup clutch (generically represented by a box 20 in FIG. 1)
disposed in parallel with the impeller and turbine (or friction
plates, if so equipped). Lockup clutch 20 may be configured to
selectively and mechanically lock the crankshaft directly to the
gear box input shaft, such that both shafts rotate at the same
speed. Lockup clutch 20, if included, may be activated manually or
automatically, as will be described below.
[0017] Gear box 18 may include numerous components that interact to
transmit power received from power source 12 (via torque converter
16) to pump 14. In particular, gear box 18 may embody a mechanical
transmission having one or more forward gear ratios. In some
embodiments, gear box 18 may also include a neutral position and/or
one or more reverse gear ratios. In embodiments where more than one
gear ratio is included, gear box 18 may additionally include one or
more clutches (not shown) for selectively engaging predetermined
combinations of gears (not shown) that produce a desired gear
ratio.
[0018] Gear box 18, if equipped with multiple gear combinations,
may be an automatic-type transmission wherein shifting between gear
ratios is based on a power source speed, a maximum operator
selected gear ratio, a load from pump 14, and/or a fluid pressure
within gear box 18. Alternatively, gear box 18 may be a manual
transmission, Wherein the operator manually engages the desired
gear combinations. Regardless of the type of transmission, the
output of gear box 18 may be connected to rotatably drive an input
shaft of pump 14.
[0019] In the disclosed embodiment, each ratio of gear box 18 may
be about 7:1 or less. In particular, gear box 18 may be configured
to produce an output speed that is about the same as or up to seven
times less than an input speed received by gear box 18. This
reduction may typically be too small to accommodate slurry pumping
applications with high accuracy. That is, transmissions typically
used in slurry pumping applications require speed reductions of 7:1
or greater. However, When used in conjunction with torque converter
16 in its unlocked state (i.e., during a torque converter drive
mode), slippage between the impeller and the turbine (or between
the friction plates) combines with the ratio reduction of gear box
18 to produce sufficiently high speed reductions (i.e., reductions
greater than about 7:1). In this way, a smaller, lighter, and
cheaper gear box 18 may be used to produce flow rates required in
slurry pumping applications.
[0020] Pump 14, in the disclosed example, is a positive
displacement plunger pump capable of generating an output flow rate
of about 10-20 gallons per minute. In particular, pump 14 may
include a crankshaft, one or more plungers rotatably connected to
the crankshaft, and valves (e.g., one-way inlet and discharge
valves) disposed within a common housing. Pump 14 may be configured
to transport a fluid/particle mixture (e.g., oil sands, sewage,
petroleum, petrochemicals, cement, etc.) by the conversion of
rotational kinetic energy of the plunger(s) to hydrodynamic energy
of the mixture. The mixture may be drawn into the housing through
an inlet valve during an expanding stroke of the plunger(s), and
pushed out of the housing through an outlet valve during a
compressing stroke of the plunger(s). In this configuration, the
crankshaft of the pump may be directly driven by the output shaft
of gear box 18 at a speed that is about seven or more times slower
than the output speed of power source 12. It is contemplated that
pump 14 may be a different type of pump, if desired, such as a
centrifugal pump, a lobe pump, or a peristaltic hose pump. Pump 14
may produce an output flow rate dependent on conditions of the
fluid/particle mixture (e.g., density, viscosity, etc), a size
(e.g., area, stroke length, and/or swept volume) of the plunger(s),
and the input rotation (i.e., speed and torque) provided by gear
box 18.
[0021] A controller 26 may he associated with pumping system 10,
and configured to regulate the output flow rate of pump 14. In
particular, controller 26 may be configured to receive from a
sensor 28 an indication of an actual output flow rate of pump 14,
receive from the operator an indication of a desired output flow
rate of pump 14, and responsively adjust operation of power source
12 to reduce an error between the actual and desired output flow
rates. In one example, sensor 28 is a speed sensor associated with
the crankshaft of pump 14 and/or a shaft (input or output) of gear
box 18. In this example, signals generated by sensor 28 may be used
by controller 26 to calculate the actual flow rate of pump 14. It
is contemplated, however, that sensor 28 could otherwise be
configured to directly sense the actual flow rate and/or sense
other or additional flow rate parameters (e.g., pressure) that
subsequently may be used by controller 26 to calculate the actual
output flow rate, if desired. Controller 26 may be configured to
adjust the speed of power source 12 by adjusting fueling of power
source 12.
[0022] Controller 26 may embody a single processor or multiple
processors that include a means for controlling an operation of
pumping system 10. Numerous commercially available processors may
perform the functions of controller 26. Controller 26 may include
or be associated with a memory for storing data such as, for
example, an operating condition, design limits, performance
characteristics or specifications of pumping system 10, operational
instructions, and corresponding fueling parameters. This data may
be stored within the memory of controller 26 in the form of one or
more lookup tables, as desired. Various other known circuits may be
associated with controller 26, including power supply circuitry,
signal-conditioning circuitry, solenoid driver circuitry,
communication circuitry, and other appropriate circuitry. Moreover,
controller 26 may be capable of communicating with other components
of pumping system 10 (e.g., with a filet system of the engine, with
lockup clutch 20, with sensor 28, etc.) via either wired or
wireless transmission and, as such, controller 26 may be connected
to or alternatively disposed in a location remote from power source
12 and/or pump 14.
[0023] The operator of pumping system 10 may be able to input
instructions via one or more interface devices (e.g., a keyboard,
touchscreen monitor, etc.) located at a control panel that also
houses controller 26. These instructions may include, among other
things, a desired output flow rate of pump 14, a desired gear ratio
of gear box 18, and/or a status of lockup clutch 20 (e.g., engaged
or disengaged). Signals indicative of these instructions may be
directed to controller 26 for further processing.
INDUSTRIAL APPLICABILITY
[0024] The disclosed pumping system may be used in any application
to generate a flow of fluid. The disclosed pumping system may be
particularly applicable to slurry pumping applications, where flow
control accuracy over dense mixtures is important. The disclosed
pumping system may provide for improved flow control accuracy of a
relatively dense fluid/particle mixture in a lightweight,
inexpensive configuration. Operation of pumping system 10 will now
be described in detail.
[0025] One exemplary application for pumping system 10 is a
cementing application. In a cementing application, a relatively
dense cement slurry is directed into a well bore by pump 14 during
drilling of the well. This slurry displaces drilling fluids in the
bore, and forms a casing for the bore during the drilling process.
in order for the integrity of the casing to be maintained, the flow
rate of the slurry into the well bore must be tightly
controlled.
[0026] To initiate operation of pumping system 10 during the
cementing process, the operator may input, via the control panel, a
desired output flow rate of pump 14, a desired ratio of gear box
18, and a desired state of lockup clutch 20. In most slurry pumping
applications, lockup clutch 20 (if gear box 18 is equipped with
lockup clutch 20) may remain disengaged, such that the input
rotation of torque converter 16 is at least somewhat independent of
the output rotation of power source 12. As described above, the
torque converter drive mode of operation, in combination with the
available ratios of gear box 18, may produce overall ratios of
about 7:1 or higher. In some applications, gear box 18 may have
only one available gear combination and/or controller 26 may be
configured to automatically select a gear combination without
receiving corresponding instruction from the operator. Accordingly,
it may be possible that the operator is required to only input a
desired output flow rate of pump 14.
[0027] While pumping the cement slurry into the well bore, the
actual output flow rate of pump 14 may be monitored by way of
sensor 28. Specifically, signals generated by sensor 28 may he
directed to controller 26 and, based on the values of these
signals, controller 26 may calculate or otherwise determine the
actual output flow rate of pump 14. Controller 26 may then
determine an error as a function of the actual and desired output
flow rates. For example, controller 26 may determine a difference
between these flow rates.
[0028] If the supply of cement slurry is too fast or too slow,
casing formation may be disrupted. Accordingly, controller 26 may
be configured to reference the difference between the actual output
flow rate and the desired output flow rate with the lookup table
stored in memory to determine if a change in the speed of power
source 12 is required to properly support the drilling operation. A
new speed and/or fuel setting of power source 12 may then be
determined that produces the required change output flow rate, and
controller 26 may issue a command to power source 12 to operate at
the new fuel setting and/or speed (i.e., controller 26 may only
command a new speed setting, and a separate speed governor may then
issue a corresponding fuel command). In other words, the output
flow rate of pump 14 may be directly controlled via speed control
of power source 12 when pumping system 10 is operating in the
torque converter drive mode.
[0029] The disclosed pumping system 10 may provide an accurate way
to control the output flow rate of pump 14. In particular, based on
feedback from sensor 28, controller 26 may adjust the speed of
(e.g., the fueling of) power source 12 until the actual output flow
rate of pump 14 substantially matches the output flow rate desired
by the operator (e.g., within a threshold amount). In the exemplary
cementing application, controller 26 may adjust the speed of power
source 12 to maintain a substantially constant output flow rate of
about 10-20 gallons per minute, even with variations in load on
pump 14. And, in contrast to the step-wise adjustment of
conventional slurry pumping systems, the amount of power source
speed adjustment may be infinitely variable, allowing for fine
control.
[0030] The disclosed pumping system may also be lightweight and
inexpensive. In particular, because gear box 18 may require fewer
gear combinations (e.g., only one) and/or gear combinations
provided by way of smaller and cheaper gear sets, the weight and
cost of gear box 18 may be low.
[0031] It will be apparent to those skilled in the art that various
modifications and variations can he made to the pumping system of
the present disclosure. Other embodiments of the pumping system
will be apparent to those skilled in the art from consideration of
the specification and practice of the invention disclosed herein.
For example, it is contemplated that power source 12, torque
converter 16, and transmission 18 could alternatively or
additionally be connected to drive at variable speed and torque
another device utilized in the well-forming process. For example,
pump 14 may he replaced by or joined by a fracking pump and/or a
drill that is driven by the output shaft of transmission 18. In
these embodiments, the well-forming device(s) could be speed
controlled in the same manner described above with respect to pump
14 (i.e., the output of these devices may be monitored and varied
by adjusting operation of power source 12). It is intended that the
specification and examples be considered as exemplary only, with a
true scope of the invention being indicated by the following claims
and their equivalents.
* * * * *