Note: Descriptions are shown in the official language in which they were submitted.
CA 02709048 2010-07-06
ARTIFICIAL LIFT AND TRANSFER PUMP
The present invention relates to reciprocating pumps and more particularly to
downhole
pumps for oil and gas wells.
BACKGROUND OF THE INVENTION
Artificial lift methods play an important part in the oil and gas industry.
With the
higher costs to operate aging oil and gas wells producers, diminishing
reserves of so
called easy oil and gas, need for de-watering of the gas wells and development
of new
technologies such as Steam Assisted Gravity Drainage (SAGD) processes, the
need for
artificial lifting equipment is greater than ever.
Typical oil and gas wells can range in depth from approximately 200 ft to more
than 20,000 ft and require pumps that are unique in their configuration and
capabilities.
The pumps must be placed downhole and therefore their outside dimensions are
limited
because they must fit within the casing of the well. Additionally, these pumps
are
installed as close as possible to the bottom of the well in order to achieve
the maximum
possible drawdown of often multiphase fluid in the well. The output pressure
required of
the pump varies directly with the depth that the fluid must be lifted. For
example, to
compensate for the lift required and the fluid friction in the tubing, a
10,000 ft well might
require a 4,000 lb/in2 pump.
Pumps that are currently used in the oil and gas industry include positive
displacement pumps. These positive displacement pumps, in contrast to
rotodynamic
pumps, can pump gases as well as liquids so they are suitable for very high
gas fractions.
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They can also give high discharge pressures. However, positive displacement
pumps
work with small clearances and so are more susceptible to sand and corrosion.
These
small clearances also affect their applicability in high temperature
applications such as
e.g. are Steam Assisted Gravity Drainage (SAGD) processes.
One type of positive displacement pump is the hydraulic reciprocating pump.
Several prior art designs of hydraulic reciprocating pumps for multiphase
fluids are
available, including double acting, balanced-design and single acting pumps.
Although,
there is no standardization of design among the various manufacturers, and the
various
models are quite diverse, they typically have the same basic structure
consisting of an
engine piston and engine cylinder with an engine-reversing valve, along with a
pump
barrel and plunger. These are assembled into one unit, and a polished rod
connects the
engine piston and the engine-reversing valve to the pump plunger so the three
reciprocate
together. In all of these designs the engine module, engine-reversing valve
module and
the pump module are separated from each other, connected together by the
polished rod.
Thus, to increase the stroke of the pump it is necessary to increase not only
the stroke of
the engine but also to increase the stroke of the engine-reversing valve. As a
result, to,
increase the pumping rate of the pump by increasing its stroke by e.g. 1 foot,
the overall
length of the pump may have to be increased three-fold by 3 feet.
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SUMMARY OF THE INVENTION
It is to be understood that other aspects of the present invention will become
readily apparent to those skilled in the art from the following detailed
description,
wherein various embodiments of the invention are shown and described by way of
illustration. As will be realized, the invention is capable for other and
different
embodiments and its several details are capable of modification in various
other respects,
all without departing from the spirit and scope of the present invention.
Accordingly the
drawings and detailed description are to be regarded as illustrative in nature
and not as
restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to the drawings wherein like reference numerals indicate similar .
parts
throughout the several views, several aspects of the present invention are
illustrated by
way of example, and not by way of limitation, in detail in the figures,
wherein:
Fig. 1 is a schematic illustration of a pump in a fast aspect;
Fig. 2 is a schematic illustration of the pump in Fig. 1, during an intake
stroke by
a top piston;
Fig. 3 is a schematic illustration of the pump of Fig. 1, with a reversing
sleeve
shifting while the top piston is at a bottom of an intake stroke;
Fig. 4 is a schematic illustration of the pump of Fig. 1 during a discharge
stroke of
the top piston;
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Fig. 5A is a top. schematic illustration of the pump of Fig. 1 in one aspect;
Fig. 5B is a bottom schematic illustration of the pump in Fig. 5A;
Fig. 6 is a schematic illustration of a reversing device in a first aspect, to
reverse
the direction of the pistons in the pump;
Fig. 7 is a schematic illustration of the reversing device shown in Fig. 6,
during
operation of the reversing device;
Fig. 8 is a schematic illustration of reversing device shown in Fig. 6-with
biasing
devices to reset the reversing device after use;
Fig. 9 is a schematic illustration of a reversing device in a second aspect;
Fig. 10 is a schematic illustration of the reversing device shown in Fig. 9,
during
the operation of the reversing device;
Fig. 11 is a schematic illustration of a reversing device in a third aspect;
Fig. 12 is a schematic illustration of the reversing device shown in Fig. 11,
during
the operation of the reversing device;
Fig. 13 is, a schematic illustration of a reversing device in a fourth aspect;
Fig. 14 is a schematic illustration of the reversing device shown in Fig. 13,
during
the operation of the reversing device;
Fig. 15 is a schematic illustration of a pump in a further aspect;
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Fig 16 is a schematic illustration of the pump of Fig. 15, during a discharge
stroke
by a top piston;
Fig. 17 is a schematic illustration of the pump of Fig. 15, during a changing
of
direction of motion by the top piston;
Fig. 18 is a schematic illustration of the pump of Fig. 15, during a reversal
of
motion;
Fig. 19 is a schematic illustration of the pump of Fig. 15., during an intake
stroke
by the top piston;
Fig. 20A is a schematic illustration of a pump being installed in a parallel
free
configuration;
Fig. 20B is a schematic illustration of the pump in Fig. 20A installed in
place in
the casing;
Fig. 20C is a schematic illustration of the pump in Fig. 20A being retrieved
from
the casing;
Fig. 21A is a schematic illustration of a pump installed in a casing free
configuration;
Fig. 21B is a schematic illustration of a pump installed in a further aspect
of a
casing free configuration;
Fig. 22 is a schematic illustration of a number of pumps configured in
parallel to
form a cluster;
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Fig. 23 is a schematic illustration of a number of clusters of parallel pumps
installed in a series;
Fig. 24 is a schematic illustration of a prior art reciprocating pump
operating in a
seal-less configuration;
Fig. 25 is a schematic illustration of centering mechanism;
Fig. 26 is a schematic illustration of a prior art reciprocating pump
operating in a
seal configuration;
Fig. 27 is a schematic illustration of a reciprocating pump operating in a
seal
configuration;
Fig. 28 is a schematic illustration of a porting mechanism of a pump having a
groove;
Fig. 29 is a top view of the groove in Fig. 28;
Fig. 30 is a side view of the groove in Fig. 28;
Fig. 31 is a schematic illustration of a porting mechanism with a second port
in an
open position;
Fig. 32 is a schematic illustration of the porting mechanism of Fig. 31 with a
sealing ring over a first port; and
Fig. 33 is a schematic illustration of the porting mechanism of Fig. 31 with a
first
port in an open position.
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DESCRIPTION OF VARIOUS EMBODIMENTS
Figs. 1-4 are schematic illustrations of a pump 1 with a first end 3 and a
second
end 4, in a first aspect. Pump 1 has an outer housing 2, with an inner housing
5 provided
within the outer housing 2. The inner housing 1 contains a first compression
chamber
11 A having a first piston 1 OA and a second compression chamber 11 B having a
second
piston l OB. The first piston 1 OA and the second piston 1OB are connected
together with
a connecting rod 7 so that the first piston 1 OA and second piston 1OB are
forced to move
in conjunction by the connecting rod 7.
The outer housing 2 may be a bottom portion of the tubing or coiled tubing,
i.e.
the tailpipe, or may define a device connected to the tail pipe (or-other-
lower point) of the
wellbore string (not shown). In Figs. 1-4, the outer housing 2 is shown
connected to a
power fluid conduit 30 that supplies high-pressure power fluid to a power
fluid supply
conduit 24 that runs between the outer housing 1 and the inner housing 5 and
supplies
power fluid to drive the pump 1. The power fluid can be a gas or liquid.. A
target fluid
intake conduit 27 and a target fluid discharge conduit 22 are provided within
the outer
housing 2, but outside the inner housing 5. The target fluid intake conduit 27
is provided
with an opening 21 at the second end 4 of the housing 3 so that it can be
placed in contact
with a target fluid to be moved with the pump 1 (e.g. formation fluid down a
well bore
the pump 1 is placed in). The target fluid intake conduit 27 directs target
fluid from the
opening 21 to the first compression chamber 11 A and second compression
chamber 11 B,
where the target fluid will be drawn in by the first compression chamber 1 1A
and second
compression chamber 11B, respectively, before it is discharged to a target
fluid discharge
conduit 22.
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Figs 5A and 5B are top and bottom schematic illustrations of the pump 1 in one
aspect. The power fluid supply conduit 24, target fluid intake conduit 27 and
target fluid
conduit 22 are all defined by the annulus formed between the outer housing 2
and the
inner housing 5. The annulus between the outer housing 2 and the inner housing
5 is
divided into different sections by partitions 32 to form the power supply
conduit 24,
target fluid intake conduit 27 and target fluid conduit 22.
Referring again to Figs. 1-4, the first compression chamber 11A is provided
with
an intake valve 15A, between the target fluid intake conduit 27 and the first
compression
chamber 11A, and a discharge valve 14A, between the first compression chamber
11A
and the target fluid discharge conduit 22. During an intake stroke of the
first piston 10A,
with the first piston I OA moving towards the second end 4 of the pump 1 (as
shown in
Fig. 1), the intake valve 15A is open and the discharge valve 14A is closed
causing target
fluid from the target fluid intake conduit 27 to be drawn into the first
compression
chamber I IA through the open intake valve 15A. During a discharge stroke of
the first
piston IOA, with the first piston IOA moving towards the first end 3 of the
pump 1 (as
shown in Fig. 4), the discharge valve 14A is open and the intake valve 15A is
closed,
causing target fluid that was drawn into the first compression chamber IOA
during the
previous intake stroke of the first piston 1 OA to be discharged out the
discharge valve
14A into the target fluid discharge conduit 22 where it will eventually exit
the pump 1.
In a similar manner, the second compression chamber 1 I B is also provided
with
an intake valve 15B, between the second compression chamber I IB and the
target fluid
intake conduit 27, and a discharge valve 14B, between the second compression
chamber
11B and the target fluid discharge conduit 22. Through the opening and closing
of the
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intake valve 15B and the discharge valve 14B, the second compression chamber
11B
pumps target fluid. During an intake stroke of the second piston IOB (as shown
in Fig.
4), target fluid is drawn into the second compression chamber 11B from the
target fluid
intake conduit 27 and then discharged from the second compression chamber 11B
during
a subsequent discharge stroke of the second piston 10B (as- shown in Fig. 1),
discharging
the target fluid in the second compression chamber 1lB to the target fluid
discharge
conduit 22 where the target fluid will eventually exit the pump 1.
In this manner, both the first compression chamber 1IA and second chamber 11B
act to pump the target fluid with both the first piston 1OA and second piston
lOB acting
as pumping pistons, drawing in and expelling target fluid in a reciprocating
manner.
In an aspect, the intake valves 15A, 15B and the discharge valves 14A, 14B are
one-way valve ball valves that operate with pressure differentials. When the
pressure of
fluid in the first compression chamber 11A is lower than the pressure of the
target fluid in
the target fluid intake conduit 27, by an amount sufficient to overcome a bias
of the
valve, the intake valve 15A opens. When the pressure of the fluid in the first
compression chamber 11A is greater than the pressure in the target fluid
discharge
conduit 22, by an amount sufficient to overcome the bias of the valve, the
discharge valve
14A opens. Similarly, when the pressure of fluid in the second compression
chamber
1 lB is lower than the pressure of the target fluid in the target fluid intake
conduit 27 by
an amount to overcome a bias of the valve, the intake valve 15B opens and when
the
pressure of the fluid in the second compression chamber 11 B is greater than
the pressure
in the target fluid discharge conduit 22 by an amount to overcome a bias of
the valve, the
discharge valve 14B opens.
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In addition to the first piston 1OA and second piston IOB operating as pumping
pistons, the first piston 1 OA and second piston 1 OB also operate as engine
pistons to drive
the pump 1. A first chamber 12A is provided adjacent to the first piston 1OA
on an
opposite side of the first piston 1OA from the first compression chamber 11A.
A second
chamber 12B is provided adjacent the second piston 10B on an opposite side of
the
second piston 1OB from the second compression chamber 11B. By introducing
power
fluid into the first chamber 12A, the power fluid acts on the first piston
1OA, on an
opposite side of the first piston 1OA from the first compression chamber 11A,
driving the
first piston 10A in a discharge stroke. By introducing power fluid into the
second
chamber 12B, the power fluid acts on the second piston 10B, on an opposite
side of the
second piston lOB from the second compression chamber 11B, driving the second
piston
10B in a discharge stroke.
By altering the size of the connecting rod 7 and thereby the volume of the
first
chamber 12A and second chamber 12, the operating parameters, such as pumping
output
can be altered. The change in outside diameter dimension of the connecting rod
7 has an
effect on the ratio of the supplied power fluid to the volume of discharged
target fluid and
the power fluid pressure requirements.
A reversing sleeve 6 is provided, slidably mounted in the inner housing 5
between
the first piston 1OA and the second piston IOB with a bumper 29 provided to
limit the
range of motion of the reversing sleeve 6. The reversing sleeve 6 operates to
reverse the
direction of motion of the first piston 1OA and second piston 10B when the
first piston
1OA and second piston l OB are at the end of either an intake stroke or a
discharge stroke.
The reversing sleeve 6 separates the first chamber 12A and the second chamber
112B.
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Through the positioning of the reversing sleev-6, power fluid is routed into
either
the first chamber 12A or the second chamber 12B to drive the pump 1. With
power fluid
being directed into the first chamber 12A the first piston 1OA is driven
through a
discharge stroke, as shown in Fig. 4. With power fluid directed to the second
chamber
12B, the second piston lOB is driven through a discharge stroke, as shown in
Fig. 1.
Because the first piston IOA and second piston IOB are connected by the
connecting rod
7, when the first piston 1 OA is driven through a discharge stroke towards the
first end 3 of
the pump 1, the connecting rod 7 pulls the second piston 10B through an intake
stroke
and when the second piston l0B is driven through a discharge stroke by the
power fluid,
the connecting rod 7 pulls the first piston 1 OA through an intake stroke.
Power fluid is introduced to the first chamber 12A through a power fluid inlet
port
8A passing into the power fluid supply conduit 24 and to the second chamber
lOB
through a second power fluid inlet port 8B passing into the power fluid supply
conduit
24. Both the first housing inlet port 8A and the second housing inlet port 8B,
passing
through the inner housing 5.
A first housing exhaust port 9A and a second housing exhaust port 9A are
provided passing through the inner housing 5 to the target fluid discharge
conduit 22
where fluid vented from the first chamber 12A and second chamber 12B,
respectively,
will mix with the target fluid being discharged from the pump 1, although a
person
skilled in the art will appreciate that a separate exhaust fluid conduit could
be used to
keep vented exhaust fluid from co-mingling with the target fluid being moved
by the
pump 1.
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A first reversing sleeve exhaust port 19A is provided in the reversing sleeve
6,
positioned so that when the reversing sleeve 6 has been moved towards the
first piston
10A, during an intake stroke of the first piston 10A (as shown in Fig. I), the
first
reversing sleeve exhaust port 19A aligns with the first housing exhaust port
9A causing
the first chamber 12A to be in fluid communication with the target fluid
discharge
conduit 22, venting fluid from the first chamber 12A to the target fluid
discharge conduit
22, where the vented fluid will commingle with the target fluid being
discharged from the
pump 1. The second chamber 12B is vented with a second reversing sleeve
exhaust port
19B provided in the reversing sleeve 6 and positioned so that second reversing
sleeve
exhaust port 19B aligns with a second housing exhaust port 9B, in fluid
communication
with the target fluid discharge conduit 22, when the second piston lOB is in
an intake
stroke, as shown in Fig. 4.
Referring to Fig. 1, during a discharge stroke of the second piston 10B, the
reversing sleeve 6 has been moved towards the first end 3 of the pump 1 until
the
reversing sleeve 6 has been stopped by the bumper 29. In this position, the
reversing
sleeve 6 is exposing the second power fluid inlet port 8B placing the second
chamber
12B in fluid communication with the power fluid supply conduit 24, allowing
power fluid
to enter the second chamber 12B. At the same time, the reversing sleeve 6 is
blocking
the second housing exhaust port 9B, preventing fluid in the second chamber 12B
from
being vented to the target fluid discharge conduit 22. The power fluid being
introduced
into the second chamber 12B, from the power fluid supply conduit 24, through
the second
power fluid intake port 8B, drives the second piston 10B through the discharge
stroke
causing the second compression chamber 1lB to discharge target fluid from the
second
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CA 02709048 2010-07-06
compression chamber 11B through the discharge valve 14B into the target fluid
discharge
conduit 22.
At the same time the second 10B is traveling through the discharge stroke,
the first piston IOA is being pulled through an intake stroke by the
connecting rod 7.
During the intake stroke of the first piston 1OA, the reversing sleeve 6
blocks the first
power fluid inlet port 8A in the inner housing 5, preventing power fluid from
entering the
first chamber 12A from the power fluid supply conduit 24. At the same time,
the first
power fluid inlet port 8A is being blocked by the reversing sleeve 6, the
first reversing
sleeve exhaust port 19A is aligned with the first housing exhaust port 9A
allowing fluid
in the first chamber 12A to be vented from the first chamber 12A, as the first
piston IOA
travels through the intake stroke, decreasing the size of the first chamber
12A and
displacing fluid in the first chamber 12A out through the first reversing
sleeve exhaust
port 19A and the first housing exhaust port 9A, where the fluid will be
discharged into
the target fluid discharge conduit 22 to co-mingle with the discharged target
fluid. As the
first piston IOA moves through an intake stroke, target fluid is drawn through
the inlet
valve 15A from the target fluid intake conduit 27 into the first compression
chamber
11A.
Referring to Fig. 4, during a discharge stroke of the first piston 10A, the
reversing
sleeve 6 has been moved towards the second end 4 of the pump 1 until the
reversing
sleeve 6 has been 'stopped by the bumper 29. In this position, the reversing
sleeve 6 is
exposing the first power fluid intake port 8A, placing the first chamber 12A
in fluid
communication with the power fluid supply conduit 24, while at the same time
blocking
the first housing exhaust port 9A and preventing the venting of fluid from the
first
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chamber 12A. The high-pressure power fluid being introduced into the first
chamber
12A from the power fluid supply conduit 24, through the first power fluid
intake port
8A, drives the first piston 10A through a discharge stroke causing the first
compression
chamber 11A to discharge target fluid through the discharge valve 14A to the
target fluid
discharge conduit 22.
At the same time, the first piston 1OA is traveling through the discharge
stroke;
the second piston 10B is being pulled through an intake stroke by the
connecting rod 7.
The reversing sleeve 6 is blocking the second power fluid inlet port 8B in the
inner
housing 5, preventing power fluid from entering the second chamber 12B and the
second
reversing sleeve exhaust port 19B is aligned with the second housing exhaust
port 9B
allowing fluid in the second chamber 12B to be vented as the second piston l
OB is pulled
along the intake stroke by the first piston 1 OA, decreasing the size of the
second chamber
12A and displacing fluid in the second chamber 12A out through the second
reversing
sleeve exhaust port 19B and the second housing exhaust port 9B, where the
fluid is
exhausted to the target fluid discharge conduit 22 to co-mingle wit the target
fluid being
discharged. The intake stroke of the second piston l OB draws target fluid
from the target
fluid inlet conduit 27 through the intake valve 15B into the second
compression chamber
1OB which will later be expelled by a subsequent discharge stroke of the
second piston
10B.
When the first piston 10A and second piston 10B have reached the end of an
intake stroke/discharge stroke or discharge stroke/intake stroke, the
direction of motion of
the first piston 10A and the second piston lOB must be reversed so that the
pump 1
continues to operate. The reversing sleeve 6 is moved so that it reverses the
direction of
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motion of the first piston 10A and the second piston lOB. To instigate the
movement of
the reversing sleeve 6, a first reversing device 40A and a second reversing
device 40B are
provided to shift the reversing sleeve 6.
The first piston 1 OA and the second piston l OB have a first boss 54A and a
second
boss 54B, respectively. The first boss 54A is provided on the first piston 10A
extending
into the first chamber 12A. The first boss 54A and a first end 60A of the
reversing sleeve
6 are sized so that an outer surface 58A of the first boss 54A mates with an
inner surface
55A of the first end 60A of the reversing sleeve 6 as the first piston I OA
approaches the a
bottom of an intake stroke.
Fig. 2 illustrates the first piston 1OA approaching the bottom of an intake
stroke.
The mating of the outer surface 58A of the first boss 54A with the inner
surface 55A of
the first end 60A of the reversing sleeve 6 partitions the first chamber 12A
into a first
boss annulus 16A and a first sleeve annulus 17A. To reverse the direction of
the pump 1,
the first reversing device 40A increases the pressure of the fluid in the
first boss annulus
16A, forcing the sleeve 6 towards the second end 4 of the piston 1, until the
reversing
sleeve 6 is stopped by the bumper 29, as shown in Fig. 3. With the sleeve 6
moved
towards the second end 4 of the pump 1 until the reversing sleeve 6 has
contacted the
bumper 29, power fluid begins to enter the first chamber 12A because the
reversing
sleeve 6 has uncovered the first power fluid inlet port 8A, with the power
fluid initially
entering the first boss annulus 16A. At the same time the shifted reversing
sleeve 6 is
allowing power fluid to enter the first chamber 12A, fluid in the second
chamber 12B is
exhausted through the aligned second exhaust port 19B and second housing
exhaust port
9B. This reverses the direction of motion of the first piston 1OA and the
second piston
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10B, causing the first piston 1OA to travel through a discharge stroke while
the second
piston l OB travels through an intake stroke.
In a similar manner, the second boss 54B on the second piston lOB extends into
the second chamber 12B. The second boss 54B and the second end 60B of the
reversing
sleeve 6 are sized so that an outer surface 58B of the first boss 54A mates
with an inner
surface 55B of the reversing sleeve 6 as the second piston l OB approaches a
bottom of an
intake stroke partitioning the second chamber 12B into a second boss annulus
and a first
sleeve annulus. To reverse the direction of the pump 1 when the second piston
10B has
reached the end of an intake stroke, the second reversing device 40A operates
in the same
manner as the first reversing device 40B, increasing the pressure of the fluid
in the
second boss annulus 16B and in turn forcing the reversing sleeve 6 towards the
first end 3
of the pump 1, until the reversing sleeve 6 is stopped by the bumper 29. In
this position,
the second chamber 12B is placed in fluid communication with the power fluid
supply
conduit 24, while the first chamber 12A is exhausted, driving the second
piston 10B into
a discharge stroke while the first piston 1 OA is pulled through an intake
stroke.
First reversing device 40A and second reversing device 40B are housed in
opposite ends of the connecting rod 7 and operate independently from each
other, so that
there is no communication between the first reversing device 40A and the
second
reversing device 40B. In this manner, the connecting rod 7 can be extended to
any
practical length to extend the strokes of the first piston 1OA and the second
piston 1OB,
without impacting the performance of the first reversing device 40A and the
second
reversing device 40B. This allows the length of the stroke to be set to meet
the
applications requirements, e.g. to prevent gas locking.
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The operating temperature of the pump 1 can be altered based on the
temperature
of the power fluid being provided to the pump 1. Because the power fluid comes
in
contact with both the first piston 10A and second piston 10B, the temperature
of the
power fluid can affect a substantial portion of the pump 1.
Figs. 6 and 7 illustrate an implementation of the first reversing device 40A,
in one
aspect. Although only the first reversing device 40A is illustrated, second
reversing
device 40B is substantially the same as first reversing device 40A and
operates in the
same manner on the second boss annulus 16B. A person skilled in the art will
be able to
readily duplicate the operation of first reversing device 40A in implementing
the second
reversing device 40B.
In this aspect of the first reversing device 40A, hydraulic multiplication is
used to
boot the pressure of the fluid in the first boss annulus 16A. This increased
pressure of the
fluid in the first boss annulus 16A acts on a first end 60A of the reversing
sleeve 6,
shifting the reversing sleeve 6 and reversing the direction of motion of the
first piston
1 OA and the second piston l OB at the bottom of an intake stroke of the first
piston 1 OA.
A booster 128 is provided in a booster chamber 132 in the connecting rod 7. On
an end of the booster 128, proximate the first piston 10A, is a booster small
piston 135
and on an other end of the booster 128 is a booster large piston 134. The
booster small
piston 135 defines a small piston chamber 148 located in the connecting rod 7
and having
a booster chamber passage 155 placing the small piston chamber 148 in fluid
communication with the first boss annulus 16A when the first piston 1OA has
partitioned
the first chamber 12A into the first boss annulus 16A and the first sleeve
annulus 17A. A
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booster passage 136 is also provided passing through the booster small piston
135 and the
booster 128 and ending in the booster chamber 132. The booster passage 136
places the
small piston chamber 148 in fluid communication with the booster chamber 32
and the
first chamber 12A through an internal vent port 50, when the first, piston l0A
is not at a
bottom of an intake stroke, and therefore allowing fluid in the first boss
annulus 16A and
the small piston chamber 148 to be vented.
The booster big piston 134 defines a big piston chamber 147 on one side of the
booster big piston 134 and the booster chamber 132 on an other side of the
booster big
piston 134. The internal vent port 50 places the booster chamber 132 in fluid
communication with the first chamber 12A and the first sleeve annulus 17A when
the
first piston lOA is partitioning the first chamber 12A into the first boss
annulus 16A and
the first sleeve annulus 17A.
A pilot port 137 and a high-flow port 138 are provided passing into the
connecting rod 7 and into the big piston chamber 147. A high-flow valve 129 is
placed at
the end of the high-flow port 138, blocking the high-flow port 128 when the
high-flow
valve 129 is not open.
Referring to Fig. 6, before the first reversing device 40A is in operation,
the
booster large piston 134 rests against a ridge 133 and the high-flow valve 129
is blocking
the entry of power fluid from the second chamber 12B through the high-flow
port 138. A
booster large piston annulus 145 is defined by the booster large piston 134
and the ridge
133, which the pilot port 137 opens into.
18
{E5796873.DOC;1 }
CA 02709048 2010-07-06
As the first piston 10A travels towards a bottom of an intake stroke, the
first
chamber 12A becomes partitioned into the first boss annulus 16A and the first
sleeve
annulus 17A. Fluid in the first sleeve annulus 17A is vented from the first
sleeve annulus
17A through the first reversing sleeve exhaust port 19A and the first exhaust
housing port
9B as the first sleeve annulus 17A decreases in volume. Fluid in the first
boss annulus
16A is also being vented as the volume of the first boss annulus 16A
decreases. The fluid
in the boss annulus 16A is vented by passing into the small piston chamber 148
through
the booster chamber passage 155 and then to the first sleeve annulus 17A
through the
booster passage 136, where it is vented through the first reversing sleeve
exhaust port
19A and the first housing exhaust port 9A from the first sleeve annulus 17A.
Meanwhile, as the first piston 1 OA reaches a bottom of an intake stroke, the
high-
flow port 138 exits the reversing sleeve 6 and passes into the second chamber
12B
coming into contact with high-pressure power fluid in the second chamber 12B.
However, the high-flow valve 129 initially prevents the power fluid from
entering the big
piston chamber 147 through the high-flow port 138. As the first piston 10A
continues
toward the bottom of the intake stroke, the pilot port 137 passes out of the
reversing
sleeve 6 and becomes exposed to the high-pressure power fluid in the second
chamber
12B. Some of this power fluid enters the pilot port 137 where it is directed
to the booster
large piston annulus 145, formed between the booster big piston 134 and the
ridge 133.
In the booster large piston annulus 145, the power fluid acts against the
booster large
piston 134, forcing the booster large piston 134 away from the ridge 133. With
the
booster large piston 134 forced away from the ridge 133, the power fluid can
pass by the
ridge 133 and come into contact with a top surface 131 of the high-flow valve
129,
19
{E5796873.DOC;1 }
CA 02709048 2010-07-06
moving the high-flow valve 129 downwards until the high-flow valve 129
contacts a
high-flow valve bumper 130, exposing the high-flow port 138 to the booster big
piston
147. With the high-flow port 138 opened, power fluid from the second chamber
12B
gains entry into the big piston chamber 147 through the high-flow port 138 and
acts
against the booster big piston 134. The pressure of the power fluid against
the booster
large piston 134 forces the booster large piston 134 upwards and, in
conjunction, the
booster small piston 135 upwards.
Referring to Fig. 7, as the booster small piston 135 and the booster large
piston
134 move upwards, propelled by the high-pressure power fluid acting on the
booster
large piston 134, the booster passage 136 becomes cut off from the booster
chamber 132
and therefore the sleeve annulus 17A, preventing fluid in the first boss
annulus 16A and
the small piston chamber 148 from being vented.
As the booster small piston 135 continues to move upwards, pushed by the
booster large piston 134, the volume of the small piston chamber 148 is
decreased.
Because the booster passage 136 is now blocked from communicating with the
first
reversing sleeve annulus 17A, the fluid in the small piston chamber 148 is
displaced
through the booster chamber passage 155 and into the first boss annulus 16A,
as the small
piston chamber 148 decreases in volume. The displaced fluid from the small
piston
chamber 148 applies a force to a top surface 61A of the first end 60A of the
reversing
sleeve 6, shifting the reversing sleeve 6 towards the second end 4 of the pump
1 until the
reversing sleeve 6 contacts the bumper 29, preventing the reversing sleeve 6
from moving
any further.
{E5796873.DOC;1 }
CA 02709048 2010-07-06
The differential in the surface area of the booster large piston 134 and the
surface
area of the booster small piston 135 causes the resultant pressure in the
small piston
chamber 148 to be greater than the pressure of the power fluid supplied to the
pump 1.
This higher pressure of the fluid in the first boss annulus 16A acting against
the reversing
sleeve 6 overcomes the force of the lower pressure power fluid acting against
the
reversing sleeve 6 in the opposite direction, resulting in the reversing
sleeve 6 shifting
away from the first boss annulus 16A and into the second chamber 12B. The
increase in
pressure generated in the small piston chamber 148 by the booster 128 must be
sufficiently greater than the pressure of the power fluid to overcome the
force applied on
the reversing sleeve 6 by the power fluid in the second chamber 12B and cause
the
reversing sleeve 6 to shift towards second end 4 of the pump 1. The desired
pressure
magnification can be achieved by the appropriate surface area ratio between
the booster
large piston 134 and booster small piston 135.
With the reversing sleeve 6 moved towards the second end 4 of the pump 1 until
the reversing sleeve 6 has contacted the bumper 29, the second reversing
sleeve exhaust -
port 19B becomes aligned with the second housing exhaust port 9B and the
second power
fluid intake port 8B becomes blocked by the reversing sleeve 6, as shown in
Fig. 7. With
the second power fluid intake port 8B blocked, power fluid no longer enters
the second
chamber 12B and, in turn, no longer enters the large piston chamber 145
through the
high-flow port 138. With the reversing sleeve 6 in this position, the first
inlet port 8A is
once again exposed to the first chamber 12A, initially to the first boss
annulus 16A. The
power fluid entering into the first boss annulus 16A passes into the small
piston chamber
148 through the booster chamber passage 155. This power fluid then acts on the
booster
21
{E5796873.DOC;1 }
CA 02709048 2010-07-06
small piston 135 forcing it towards the second piston 10B - which in turn
forces the
booster large piston 134 towards the second piston lOB, until the booster
large piston
contacts the ridge 133.
Fig. 8 illustrates the first reversing device 40A with a number of biasing
devices
to reset the booster 128 after the reversing sleeve 6 has been shifted and the
direction of
motion of the first piston 1OA and the second piston 10B reversed. A boost
return
biasing device 241 and flow valve return biasing device 242 are used to reset
the booster
128. The boost return biasing device 241 biases the booster 128 towards the
second
piston IOB and in one aspect is a spring. The flow valve return biasing device
242 biases
the high-flow valve 129 towards the ridge 133 and in one aspect is a spring.
When high-
pressure power fluid is acting on the booster big piston 134 and the top
surface 131 of the
high-flow valve 129, the force imposed on the booster 128 and the high-flow
valve 129
overcome the biasing force imposed by the boost return biasing device 241 and
the flow
valve return biasing device 242, respectively. However, when the high-pressure
power
fluid is no longer acting on the booster big piston 134 and the high flow
valve 129
because the reversing sleeve 6 has shifted reversing the direction of the
first piston 1OA
and second piston 10B, the boost return biasing device 241 and the flow valve
return
biasing device 242 place force on the booster 128 and high-flow valve 129,
respectively,
resetting the booster 128 and the high-flow valve 129 back to their initial
positions.
In an aspect, a bumper shock auxiliary device 243 is provided between the
first
piston IOA and the reversing sleeve 6 to decrease the shock between the first
piston IOA
and the reversing sleeve 6 at the bottom of an intake stroke of the first
piston 1 OA. In one
aspect, the bumper shock auxiliary device 243 could be a spring.
22
{E5796873.DOC;t }
CA 02709048 2010-07-06
Referring to Figs. 9 and 10, in a further aspect of the first reversing device
40A,
hydraulic amplification is used and in shifting the reversing sleeve 6. In
some
applications the booster 128 alone may be insufficient to shift the reversing
sleeve 6 and
create the reciprocating motion of the pump 1, (e.g. dimensional
restrictions). In a further
aspect, the first reversing device 40A comprises a high-pressure chamber 344
and a low-
pressure chamber 345 in addition to the booster 128.
Although Figs. 9 and 10 illustrate only the first reversing device 40A, second
reversing device 40A can be implemented in substantially the same manner as
the first
reversing device 40, operating in the same manner on the second boss annulus
16B. A
person skilled in the art will be able to readily duplicate the operation of
the first
reversing device 40A in implementing the second reversing device 40B.
The booster 128 works as previously described to increase the pressure in the
small piston chamber 148, which in turn increases the pressure of the fluid in
the first
boss annulus 16A acting against the top surface 61A of the first end 60A of
the reversing
sleeve 6. Additionally, the high-pressure chamber 344 is provided with the
bumper 29
providing one side of the high-pressure chamber 344, while the reversing
sleeve 6
provides another. A high-pressure passage 350 passes through the reversing
sleeve 6
and into the high-pressure chamber 344. A high-pressure internal passage 352
connects
with the pilot port 137. The high-pressure passage 350 and the high-pressure
internal
passage 352 are arranged so that high-pressure chamber 344 is in fluid
communication
with the pilot port 137.
23
{E5796873.DOC;1)
CA 02709048 2010-07-06
The low-pressure port 345 is in fluid communication with a low-pressure
passage
360 and a low-pressure internal passage 362 is provided in the reversing
sleeve 6 venting
into the first chamber 12A. The low-pressure passage 360 and the low-pressure
internal
passage 362 are arranged so that the low-pressure passage 360 and the low-
pressure
internal passage 362 align when the first piston 10A is near a bottom of an
intake stroke;
causing the low-pressure chamber 345 to be in fluid communication with the
target fluid
discharge conduit 22 through the first chamber 12A.
Referring to Fig. 9, when the first piston 1OA nears a bottom of an intake
stroke
and the pilot port 137 becomes exposed to the high-pressure power fluid in the
second
chamber 12B, high-pressure power fluid enters the connecting rod 7 through the
pilot
port 137, where some of the high-pressure power fluid is directed to the
booster large
piston annulus 145, starting the booster big piston 134 moving towards the
first end 3 of
the pump I and some of the high-pressure power fluid is directed through the
high-
pressure passage 350 and the high-pressure internal passage 352 to the high-
pressure
chamber 344. In the high-pressure chamber 344 the high-pressure power fluid
acts on the
reversing sleeve 6 forcing it away from the bumper 29 and towards the second
end 4 of
the pump 1, increasing the volume of the high-pressure chamber 344. At the
same time,
fluid in the low-pressure chamber 345 is in fluid communication with the
target fluid
discharge conduit 22 where it can be exhausted from the pump 1. The fluid in
the low-
pressure chamber 345 can exit the low-pressure chamber 345 through the first
chamber
12A. As high-pressure power fluid continues to be introduced to the high-
pressure
chamber 344 forcing the reversing sleeve 6 towards the second end 4 of the
pump 1, fluid
24
{E5796873.DOC;1 }
CA 02709048 2010-07-06
escaping from the low pressure chamber 345 allows the low pressure chamber 345
to
decrease in volume.
The force exerted on the reversing sleeve 6 by the high-pressure chamber 344
acts
in conjunction with the force placed on the top surface 61A of the first end
60A of the
reversing sleeve 6 by the operation of the booster 128 increasing the pressure
of the fluid
in the first boss annulus 16A. As a result of these forces, the reversing
sleeve 6 shifts
towards the second piston lOB, until the reversing sleeve 6 contacts the
bumper 29 (as
shown in Fig. 10), blocking the second inlet port 8B and preventing power
fluid from
entering the second chamber 12B, while at the same time exposing the first
inlet port 8A,
allowing power fluid to be introduced into the first boss annulus 16A and
subsequently
the entire first chamber 12A as the first boss 54A moves out of the first end
60A of the
reversing sleeve 6, as the first piston I OA moves through a discharge stroke.
At the same
time, the shifting of the reversing sleeve 6 causes the second chamber 12B to
be vented to
the target fluid discharge conduit 22, allowing fluid to exit the second
chamber 12B,
while the first housing exhaust port 9A is blocked from the first chamber 12A,
preventing
fluid in the first chamber 12A from escaping.
The high-pressure chamber 344 and low-pressure chamber 345 will not have to be
reset, because the reversing sleeve 6 will be shifted back into the initial
position shown in
Fig. 9 by the operation of the second reversing device 40B and the movement of
the
reversing sleeve 6 at the end of the discharge stroke of the first piston 1
OA. The booster
128 will be reset as described above, with the aid of the boost return biasing
device 241
and the flow valve return biasing device 242.
{E5796873.DOC;1 }
CA 02709048 2010-07-06
Referring to Figs. 11 and 12, in a further aspect of the first reversing
device 40A a
pressure equalization spool 432 is provided in the connecting rod 7 that works
in
conjunction with the high-pressure chamber 344 and low-pressure chamber 345 to
shift
the reversing sleeve 6, changing the direction of motion of the first piston
1OA and
second piston 10B. The pressure equalization spool 432 has a central passage
410, a
pressure equalization shutter 452, a pressure equalization piston 451 and a
pressure
equalization port 449. Although only the first reversing device 40A is
illustrated in Figs.
9 and 10, second reversing device 40A is substantially the same as first
reversing device
40 and operates in the same manner on the second boss annulus 16B. A person
skilled in
the art will be able to readily duplicate the operation of first reversing
device 40A in
implementing the second reversing device 40B.
A venting passage 455 places the first boss annulus 16A in fluid communication
with the central passage 410 of the pressure equalization spool 432, which is
initially
vented to the target fluid discharge conduit 22 through the internal vent port
50, the first
chamber 12A and the first reversing sleeve exhaust port 19A and the first
exhaust
housing port 9A during an intake stroke of the first piston 10A. Initially,
the high-
pressure chamber 444 is isolated from the central passage 410 because it is
blocked by
the pressure equalization spool 432. The low-pressure chamber 345 is in fluid
connection
with the internal vent port 50 which places the low-pressure chamber 345 in
fluid
communication with the target fluid discharge conduit 22 through the first
reversing
sleeve exhaust port 19A and the first exhaust housing port 9B during an intake
stroke of
the first piston 1 OA.
26
{E5796873.DOC;1 }
CA 02709048 2010-07-06
As the first piston 10A continues through the discharge stroke, the high-flow
port
138 in the connecting rod 7 passes into the second chamber 12B. Initially, the
high-flow
port 138 remains closed because of equalized pressure across the pressure
equalization
shutter 452.
Referring to Fig. 11, when the pilot port 137 passes out of the reversing
sleeve 6
into the second chamber 12B, the pilot port 137 comes into contact with the
high-
pressure power fluid in the second chamber 12B. Some of this high-pressure
power fluid
in the second chamber 12B enters the pilot port 137, where it acts on the
pressure
equalization piston 451 forcing the pressure equalization spool 432 towards
the first
piston 10A.
Referring to Fig. 12, as the pressure equalization spool 432 is moved towards
the
first piston 1 OA, a number of things occur: the pressure equalization shutter
452 uncovers
the high-flow port 138; the pressure equalization port 449 aligns with the
high-pressure
internal passage 352 and the high-pressure passage 350 leading to the high-
pressure
chamber 344; and, the equalization spool 432 covers the internal vent port 50.
By uncovering the high-flow port 138, the pressure equalization shutter 452
allows high-pressure power fluid to enter the central passage 410. From the
central
passage 410, the power fluid can enter the first boss annulus 16A through the
venting
passage 455 and the high-pressure chamber 344, however, the power fluid in the
central
passage 410 can not exit through the internal vent port 50 because the
internal vent port
50 is now blocked by the pressure equalization spool 432.
27
{E5796873.DOC;1 }
CA 02709048 2010-07-06
The reversing sleeve 6 is shifted towards the second piston 10B through forces
exerted on the top surface 61A of the first end 60A of the reversing sleeve 6
and the
pressure exerted by the power fluid in the high-pressure chamber 344. Power
fluid
routed to first boss annulus 16A acts on the top surface 61A of the first end
60A of the
reversing sleeve 6 placing a force, in the direction of the second piston 10B,
on the
reversing sleeve 6. Power fluid entering the high-pressure chamber 344 helps
shift the
reversing sleeve 6 towards the second piston 10B. Because the low-pressure
chamber
345 is in fluid communication with the target fluid discharge conduit 22
through the
internal vent port 50, the first chamber 12A, the first reversing sleeve
exhaust port 19A
and the first exhaust housing port 9A, the low-pressure chamber 345 decreases
in volume
allowing the increase in volume of the high-pressure chamber 344 driven by the
power
fluid. The expansion of the high-pressure chamber 344 causes the reversing
sleeve 6 to
shift towards the second end 4 of the pump 1.
Referring to Fig. 12, when the reversing sleeve 6 has been shifted towards the
second end 4 of the pump 1 until the reversing sleeve 6 has contacted the
bumper 29, the
power fluid inlet port 8B is cut off from the second chamber 10 preventing
additional
high-pressure power fluid from entering the second chamber 10 and thereby the
central
passage 410 through the high-flow port 138 and preventing a force acting on
the pressure
equalization piston 451, forcing it towards the first end 3 of the pump 1.
With the
pressure equalization spool 432 no longer being forced towards the first
piston 1OA, a
pressure equalization bias device 431 resets the pressure equalization spool
432 by
returning the pressure equalization spool 432 to its initial position (as
shown in Fig. 11).
In one aspect, the pressure equalization bias device can be a spring.
28
{E5796873.DOC;1 }
CA 02709048 2010-07-06
In the embodiment of the first reversing device 40A shown in Figs. 13 and 14,
the
pressure of the fluid in the first boss annulus 16A acting on a top surface
61A of the first
end 60A of the reversing sleeve 6 is equal to the pressure of the power fluid,
because the
power fluid is allowed to pass directly into the first boss annulus 16A from
the central
passage 410 through the venting passage 455. In the embodiment of the first
reversing
device 40A shown in Figs. 13 and 14, a plunger equalization spool 532 is
provided. The
plunger equalization spool 532 has a central passage 510, a plunger 553, a
pressure
equalization shutter 552, a pressure equalization piston 551 and a pressure
equalization
port 549.
Although only the first reversing device 40A is illustrated in Fig. 13 and 14,
the
second reversing device 40A is substantially the same as first reversing
device 40A and
operates in the same manner on the second boss annulus 16B. A person skilled
in the art
will be able to readily duplicate the operation of first reversing device 40A
in
implementing the second reversing device 40B.
Similar to the aspect of the first reversing device 40A shown in Figs. 12 and
13,
initially the high-pressure chamber 344 is isolated from the central passage
510 because it
is blocked by the plunger equalization spool 532. The low-pressure chamber 345
is in
fluid connection with the internal vent port 50 which places the low-pressure
chamber
445 in fluid communication with the target fluid discharge conduit 22 through
the first
reversing sleeve exhaust port 19A and the first exhaust housing port 9A during
an intake
stroke of the first piston 4A.
29
(E5796873.DOC;1)
CA 02709048 2010-07-06
The plunger equalization spool 532 has a plunger 553 provided with the plunger
553 defining a plunger chamber 548. A venting passage 555 places the first
boss annulus
16A in fluid communication with the plunger chamber 548. The plunger chamber
548 is
initially vented to the first chamber 12A through an internal plunger passage
536, the
internal vent port 50, the first chamber 12A and the first reversing sleeve
exhaust port
19A and the first exhaust housing port 9A during an intake stroke of the first
piston 1 OA.
In operation, as the first piston 10A approaches a bottom end of an intake
stroke,
the first chamber 12A is partitioned into the first boss annulus 16A and the
first sleeve
annulus 17A. When this first occurs, fluid displaced from the first sleeve
annulus 17A
can initially be exhausted from the plunger chamber 548 through the internal
plunger
passage 536 and eventually through the first chamber 12A to the target fluid
discharge
conduit 22.
As the first piston 10A continues to travel along towards the bottom end of
the
intake stroke, the high flow port 138 in the connecting rod 7 passes into the
second
chamber 12B. Initially, the high flow port 138 remains closed because of
equalized
pressure across the pressure equalization shutter 552. As the first piston 10A
continues
through the intake stroke, the pilot port 137 passes out of the reversing
sleeve 6 into the
second chamber 12B coming into contact with the high-pressure power fluid in
the
second chamber 12B. Some of this high-pressure power fluid in the second
chamber 12B
enters the pilot port 137 where it acts on the pressure equalization piston
551 forcing the
plunger equalization spool 532 towards the first piston 10A. As the plunger
equalization
spool 532 moves towards the first piston 10A, the pressure equalization
shutter 552
uncovers the high-flow port 138 and the pressure equalization port 549 aligns
with high-
{E5796873.DOC;1 }
CA 02709048 2010-07-06
pressure passage 352 and the high-pressure internal passage 350 leading to the
high-
pressure chamber 344.
By uncovering the high-flow port 138, the pressure equalization shutter 552
allows high-pressure power fluid to enter the central passage 510. With high-
pressure
power fluid entering the central passage 510, the power fluid acts on the
plunger 553,
moving the plunger 553 towards the first piston 1OA. As the plunger 553 moves
towards
the first piston 10A, the plunger passage 553 is blocked from the first
chamber 12A
preventing fluid in the plunger passage 553 from being exhausted to the target
fluid
discharge conduit 22. The decreasing volume of the plunger chamber 548 as the
plunger
553 is moved towards the first piston 1OA displaces fluid out of the plunger
chamber 548
through the venting passage 555 and into the first boss annulus 16A where the
pressure of
this fluid will act on the top surface 61A of the first end 60A of the
reversing sleeve 6
creating a force on the first end 60A of the reversing sleeve 6 towards the
second end 4 of
the pump 1.
The force of the fluid, pressurized by the plunger 532, on the top surface 61A
of
the first end 60A of the reversing sleeve 6, in conjunction with the force
excited on the
reversing sleeve 6by power fluid entering the high-pressure chamber 344,
shifts the
reversing sleeve 6 towards the second piston l OB, reversing the direction of
motion of the
first piston 1 OA and the second piston lOB.
Referring to Fig. 14, when the reversing sleeve 6 has been shifted towards the
second piston 1OB until the reversing sleeve 6 has contacted the bumper 29,
the second
housing inlet port 8B is cut off from the second chamber 12B preventing
additional high-
31
{E5796873.DOC;1 }
CA 02709048 2010-07-06
pressure power fluid from entering the second chamber 12B and thereby the
central
passage 510 through the high flow port 138. With the plunger equalization
spool 532 no
longer being forced towards the first piston 1OA, a pressure equalization
return biasing
device 531 is used to reset the plunger equalization spool 532 by returning it
to its initial
position (as shown in Fig. 13). In one aspect, the pressure equalization
return biasing
device 531 can be a spring.
The size of the plunger 535 in comparison to the central passage 510 causes a
resultant pressure magnification in the fluid in the plunger compression
chamber 548 as
power fluid acting in the central passage 510 moves the plunger 535 towards
the first
piston 1 OA. This higher pressure of the fluid in the first boss annulus b6A
acting against
the reversing sleeve 6, in conjunction with the force acting on the reversing
sleeve by the
power fluid in the high-pressure chamber 344, overcomes the force of the lower
pressure
power fluid acting against the reversing sleeve 6 in the opposite direction,
resulting in the
reversing sleeve 6 shifting towards the second end 4 of the pump 1. The
desired pressure
magnification can be achieved by the sizing of the plunger 553 in relation to
the central
passage 510.
Figs. 15-19 are schematic illustrations of a pump 601 in a further aspect.
Pump
601 has a first end 603, a second end 604, an outer housing 602, and an inner
housing
605 provided within the outer housing 602. The inner housing 605 contains a
first
compression chamber 611A having a first piston 610A and a second compression
chamber 611B having a second piston 610B. The first piston 610A and the second
piston
610B are connected together with a connecting rod 607 so that the first piston
610A and
second piston 610B are forced to move in conjunction by the connecting rod
607.
32
{E5796873.DOC;1 }
CA 02709048 2010-07-06
The outer housing 602 maybe a bottom portion of the tubing or coiled tubing,
i.e.
the tailpipe, or may define a device connected to the tail pipe (or other
lower point) of the
wellbore string (not shown). In Figs. 15-19, the outer housing 602 is shown
with a power
fluid supply conduit 624 that runs between the outer housing 601 and the inner
housing
605 and supplies power fluid to drive the pump 601. A target fluid intake
conduit 627
and a target fluid discharge conduit 622 are provided within the outer housing
602, but
outside the inner housing 605. The target fluid intake conduit 627 is provided
with an
opening 621 at the second end 604 of the pump 601 so that it can be placed in
contact
with a target fluid to be moved with the pump 601 (e.g. formation fluid down a
well bore
the pump 1 is placed in). The target fluid intake conduit 627 directs target
fluid from the
opening 621 to the first compression chamber 611 A and second compression
chamber
611B, where the target fluid will be drawn in by the first compression chamber
611A and
second compression chamber 61 1B, respectively, before it is discharged to the
target
fluid discharge conduit 622.
The first compression chamber 611A is provided with an intake valve 615A,
between the target fluid intake conduit 627 and the first compression chamber
611A, and
a discharge valve 614A, between the first compression chamber 611A and the
target fluid
discharge conduit 622. During a discharge stroke of the first piston 610A,
with the first
piston 610A moving towards the first end 603 of the pump 601 (as shown in Fig.
15), the
discharge valve 614A is open and the intake valve 615A is closed, causing
target fluid
that was drawn into the first compression chamber 610A during the previous
intake
stroke of the first piston 610A to be discharged out the discharge valve 614A
into the
target fluid discharge conduit 622 where it will eventually exit the pump 601.
During an
33
{E5796873.DOC;1 }
CA 02709048 2010-07-06
intake stroke of the first piston 610A, with the first piston 610A moving
towards the
second end 604 of the pump 601 (as shown in Fig. 19), the intake valve 615A is
open and
the discharge valve 614A is closed causing target fluid from the target fluid
intake
conduit 627 to be drawn into the first compression chamber 61 1A through the
open
intake valve 615A.
In a similar manner, the second compression chamber 611B is also provided with
an intake valve 615B between the second compression chamber 611B and the
target fluid
intake conduit 627 and a discharge valve 614B between the second compression
chamber
611B and the target fluid discharge conduit 622. Through the opening and
closing of the
intake valve 615B and the discharge valve 614B, the second compression chamber
611B
pumps target fluid. During an intake stroke of the second piston 610B (as
shown in Fig.
15), target fluid is drawn into the second compression chamber 611B from the
target fluid
intake conduit 627 and then discharged from the second compression chamber
611B
during a subsequent discharge stroke of the second piston 610B (as shown in
Fig. 19),
discharging the target fluid in the second compression chamber 611B to the
target fluid
discharge conduit 622 where the target fluid will eventually exit the pump
601.
In this manner, both the first compression chamber 611A and the second chamber
611B act to pump the target fluid with both the first piston 610A and second
piston 610B
acting as pumping pistons, drawing in and expelling target fluid in a
reciprocating
manner.
In addition to both the first piston 610A and second piston 610A acting as
pumping pistons, they also operate as engine pistons to drive the pump 601. A
first
34
{E5796873.DOC;1 }
CA 02709048 2010-07-06
chamber 612A and a second chamber 612B are provided, with the first chamber
612A
positioned adjacent the first piston 610A, on an opposite side of the first
piston 610A
from the first compression chamber 611A, and the second chamber 612B
positioned
adjacent the second piston 61 OA, on an opposite side of the second piston 61
OB from the
second compression chamber 611B. Power fluid is directed altematingly into the
first
chamber 612A and the second chamber 612B to drive the pump 610. To drive the
first
piston 610A through a discharge stroke, power fluid is directed into the first
chamber
612A and to drive the second piston 610B through a discharge stroke, power
fluid is
directed into the second chamber 612B.
The reversing spool 657 has a position piston 658 and a balancing pressure
piston
659. The balancing pressure piston 659 equalizes forces acting on the
reversing spool
during operation of the pump 601, exerting a force on the reversing spool 657
acting in
an opposite direction to the force exerted by power fluid on either the first
end 670A or
the second end 670B of the reversing spool 657. A first balancing pressure
piston
passage 671 and a second balancing pressure piston passage 672 are provided in
the
reversing sleeve 606. Based on the position of the reversing sleeve 606,
either the first
balancing pressure piston passage 671 or the second balancing pressure piston
passage
672 is placed in fluid communication with power fluid supply conduit 624 to
supply
power fluid one of the sides of the balancing pressure piston 659. If the
reversing sleeve
606 is positioned so that the first balancing pressure piston passage 671 is
provided in
fluid communication with the power fluid supply conduit 624, the power fluid
passing
through the first balancing pressure piston passage 671 to the balancing
pressure piston
659 exerts a force on the balancing pressure piston 659 towards the second end
605 of the
{E5796873.DOC;1 }
CA 02709048 2010-07-06
pump 601. If the reversing sleeve 606 is positioned so that the second
balancing pressure
piston passage 672 is provided in fluid communication with the power fluid
supply
conduit 624, the power fluid passing through the second balancing pressure
piston
passage 672 to the pressure balancing piston 659 exerts a force on the
balancing pressure
piston 659 towards the first end 603 of the pump 601.
Power fluid in either the first chamber 612A of the second chamber 612B
applies
a force to first end 670A of the reversing spool 657 or the second end 6703 of
the
reversing spool 657, respectively. The balancing pressure piston 659 exerts a
force on
the reversing spool 657 in an opposite direction from the force exerted by the
power fluid
in either the first chamber 612A or the second chamber 612B. By adjusting the
surface
area of the first end 670A and the second end 670B of the reversing spool 657
with the
surface area of the balancing pressure piston 659, the forces placed on the
reversing spool
657 can be substantially balanced, with the pressure balancing piston 659
substantially
counteracting the forces placed on the reversing sleeve 657 by the power fluid
in either
the first chamber 12A or the second chamber 12B.
With the force exerted on either the first end 670A of the second end 6703 of
the
reversing spool 657 substantially counteracted by the balancing pressure
piston 659, the
reversing spool 657 is held in place by the position piston 658. Power fluid
from the
power fluid supply conduit 624 is routed to either side of the position piston
658 to hold
the reversing spool 657 in place. A first fluid supply passage 662A is
provided in the
inner housing 605 in fluid communication with the power fluid supply conduit
624. A
second fluid supply passage 662B is provided in the reversing sleeve 606 that
aligns with
the first fluid supply passage 662A. A first slot 667A and a second slot 667B
are
36
{E5796873.DOC;1 }
CA 02709048 2010-07-06
provided on the position piston 658 to route power fluid from the fluid supply
662A and
the fluid supply 662B to either side of the position piston 658, depending on
the position
of the reversing spool 657. By altering the surface area of the position
piston 658, the
amount of force requires to shift the reversing spool 657 can be adjusted.
In this manner, the pressure balancing piston 659 counteracts the forces on
the
reversing spool 657 from the first chamber 612A and the second chamber 612B,
with the
position piston 658 holding the reversing spool 657 in position and
determining how
much force is required to shift the reversing spool 657.
A reversing sleeve piston 664 is provided to shift the reversing spool 657.
Referring to Fig. 15, the pump 601 is shown during a discharge of the first
piston
610A and an intake stroke of the second piston 610B. The reversing sleeve 606
is
initially positioned towards the second end 604 of the pump 601, exposing the
power
fluid inlet port 608A to the first chamber 612A, placing the first chamber
612A in fluid
communication with the power fluid supply conduit 624, while blocking the
exhaust port
609A. At the same time, the reversing sleeve 606 is exposing the second
exhaust port
609B to the second chamber 612B while blocking the power fluid inlet port 608B
from
the second chamber 612B. With power fluid entering the first chamber 612A
adjacent
the first piston 610A and fluid being vented from the second chamber 612B
adjacent the
second piston 610B, the first piston 610A is driven through a discharge stroke
while the
second piston 610B, pulled along by the connecting rod 607, follows along
through an
intake stroke.
37
{E5796873.DOC;1 }
CA 02709048 2010-07-06
During the discharge stroke of the first piston 610A, the power fluid exerts a
force
on the first piston 610A as well as a first side 670A of the reversing spool
657 and a first
side 680A of the reversing sleeve 606. The force exerted on the first side
670A of the
reversing spool 657 by the power fluid in the first chamber 612A is
substantially
counteracted by the force exerted on the reversing spool 657 by the pressure
balancing
piston 659 with the position piston 658 exerting a force on the reversing
spool 657
towards the second end 604 of the pump 601 and pressing the reversing spool
657 against
the reversing sleeve 606. The reversing sleeve 606 is pressed against a bumper
629 in the
inner housing 605.
When the top piston 610A reaches a top of the discharge stroke, the reversing
sleeve 606 and the reversing spool 657 act in conjunction to reverse the
direction of
motion of the first piston 610A and the second piston 610B. Referring to Fig.
16, as the
first piston 610A reaches an end of the discharge stroke, a bottom of the
second piston
610B comes into contact with the second end 670B of the reversing spool 657.
Because
of the balancing of the forces on the reversing spool by the balancing
pressure piston 659,
the second piston l OB only has to exert a force on the reversing spool 657 to
overcome
the force exerted on the reversing spool 657 towards the second piston 10B by
the
position piston 658. With the second piston 610A overcoming the force placed
on the
reversing spool 657 by the position piston 658, the reversing spool 657 is
shifted by the
second piston l OB towards the first end 603 of the pump 601.
Referring to Fig. 17, with the reversing spool 657 shifted towards the first
end 603
of the pump 601, power fluid is directed to the other side of the position
piston 658
causing the force exerted on the reversing spool 657 by the position piston
658 to act in
38
{E5796873.DOC;1 }
CA 02709048 2010-07-06
the direction of the force exerted on the reversing spool 657 by the second
piston 10B.
The shifting of the reversing spool 657 moves the first slot 682A away from
the reversing
sleeve piston passage 685 and places the second slot 682B in fluid
communication with
the reversing sleeve piston passage 685 which routes power fluid from the
power fluid
supply conduit 624 to the other side of the reversing sleeve piston 664. The
force exerted
on the other side of the reversing sleeve piston 664 drives the reversing
sleeve 606
towards the first end 603 of the piston 601, shifting the reversing sleeve
606, as shown in
Fig 18.
Referring to Fig. 19, when the reversing sleeve 606 has been shifted towards
the
first end 603 of the piston 601 until the reversing sleeve 606 has been
stopped by the
bumper 629, the reversing sleeve 606 exposes the second power fluid inlet port
608B,
which allows power fluid to enter the second chamber 612A, while at the same
time
aligning the first housing exhaust port 619A with the exhaust port 609A,
allowing fluid in
the first chamber 612A to be vented. With power fluid now entering the second
chamber
612B and the first chamber 612A being vented, the second piston 610B is driven
by the
power fluid in the second chamber 612B through a discharge stroke, while the
first piston
610A is pulled through an intake stroke by the connection rod 607.
When the second piston 610B reaches a bottom of the intake stroke, the
reversing
sleeve 606 and the reversing spool 657 act in conjunction to change the
direction of
motion of the first piston 610A and the second piston 610B.
39
{E5796873.DOC;1 }
CA 02709048 2010-07-06
Pump 1 shown in Figs. 1-4 or pump 601 shown in Figs. 14-18 can be adapted to
be deployed in the wellbore using known installation techniques for
conventional
downhole pumps.
In an aspect, the pump 1 or pump 601 can be installed in a parallel free
configuration where a U-tube arrangement is used with one of the legs of the U-
tube
supplying power fluid and the other leg directing pumped target fluid back up
to the
ground surface. Figs. 20A, 20B, 20C are schematic illustrations of a pump 701
being
installed, operated and retrieved from a well bore 710. The pump 701 could be
a pump 1
as shown in Fig. 1-4 or a pump 601 as shown in Fig. 15-19. Fig. 20A
illustrates the
pump 701 being installed in casing 710 lining a well bore. Fig. 20B
illustrates the pump
701 in position and during operation. Fig. 20C illustrates the pump 701 being
retrieved.
A first tubing string 702 and a parallel second tubing string 704 are used to
install
the pump 701 in the casing 710. The second tubing string 704 is connected to
the first
tubing string 702 near a far end 703 of the first tubing string 704. A
standing valve 708 is
provided at the far end 703 of the first tubing string 702 to seal the far end
703 of the first
tubing string 702 when the pump 701 is not in place proximate the far end 703
of the first
tubing string 702. A seal 709 is also provided in the first tubing string 702
to seal the
pump 701 in place when it is located proximate the far end 703 of the first
tubing string
702.
Referring to Fig. 20A, to install the pump 701 in place down the casing 710,
the
first tubing string 702 and the second tubing string 705 are inserted down the
casing 710.
The pump 701 is inserted in the first tubing string 702 and the first tubing
string 702 and
{E5796873.DOC;1 j
CA 02709048 2010-07-06
a cap 712 is provided at a top end 705 of the first tubing string 702 to seal
the first tubing
string 702. Power fluid is then forced down the first tubing string 702 behind
the pump
701 and then back up the second tubing string 704 to force the pump 701 down
the first
tubing string 702.
Referring to Fig. 20B, when the pump 701 reaches the far end 703 of the first
tubing string 702, the pump 701- contacts the standing valve 708. The pump 701
and the
standing valve 708 are configured so that the pump 701 engages a seat on the
standing
valve 708. The standing valve 708, along with the seal 709 forms a seal with
the pump
701. With the pump 701 no longer moving downwards, power fluid can be forced
into
the pump 701 (such as with the use of an elastomer seal on the top of the pump
701 to
reduce or prevent power fluid from entering the pump 701 until it reaches the
far end 703
of the first tubing string 702).
With power fluid now entering the pump 701, the pump 701 begins pumping
target fluid. Target fluid is drawn through the standing valve 708 into the
pump 701 and
forced by the. pump 701 up the second tubing string 704.
Referring to Fig. 20C, to retrieve the pump 701, power fluid can be forced
down
the second tubing string 704, to force the pump 701 upwards in the first
tubing string 702.
When the pump 701 is forced to a top end 705 of the first tubing string 702,
it can latch
into the cap 712 so that the pressure in the first tubing string 702 can be
bled off,
allowing the cap 712 to be removed and the pump 701 to be retrieved.
In another aspect, the pump 1 or pump 601 can be installed in a casing free
configuration. Fig. 21A is a schematic illustration of a pump 721 configured
in a casing
41
{E5796873.DOC;1 }
CA 02709048 2010-07-06
free configuration. The pump 721 (such as pump 1 or pump 601) is provided near
a
bottom of a tubing string 722 with openings 725 in the tubing string 722 where
the pump
721 exhausts target fluid being pumped.
To install the pump 721 in the casing 720 the tubing string 722 is lowered
down
the casing 722 and a packer 726 is used to seal the tubing string 722 to the
casing 720 just
below the pump 721. In this manner, an annulus 727 is formed between the
tubing string
722 and the casing 720.
To operate the, pump 721, power fluid can be forced down the tubing string 722
into a first end 728 of the pump 721 to drive the pump 721. A second end 729
of the
pump 721 is in fluid communication with the target fluid to be lifted up the
casing 720
with the pump 721 (such as oil in an underground formation). Target fluid
drawn and
expelled from the pump 721, along with spent power fluid is exhausted out the
opening
725 in the tubing string 722 and up the annulus 727 formed between the tubing
string 722
and the casing 720. In this manner, power fluid can be forced down the tubing
string 722
from the ground surface to drive the pump 721 and target fluid and exhausted
power fluid
can be forced by the pump 721 up the annulus 727, formed between the tubing
string 722
and the casing 720, to the ground surface.
Fig. 21B illustrates a variation of the installation of pump 721 in a casing
free
installation where power fluid exhausted by the pump 721 is not mixed with the
target
fluid being pumped to the ground surface. A first tubing string 731 and second
tubing
string 732 are used to install the pump 721 in the casing 720. The pump 721 is
provided
42
{E5796873.DOC;1 }
CA 02709048 2010-07-06
inside the first tubing string 731 near a bottom of the first tubing string
731 with the
second tubing string 732 connected to the pump 721.
Power fluid is forced down the second tubing string 732 and into the pump 721,
where the power fluid drives the pump 721. Target fluid is drawn into the pump
721
where it is exhausted to a first annulus 727 formed between the first tubing
string 731 and
the casing 720. The spent power fluid, rather than being mixed with the target
fluid being
pumped up to the ground surface, is directed back up a second annulus 735
between the
first tubing string 731 and the second tubing string 732. In this manner, the
spent power
fluid can be kept separate from the target fluid being pumped.
In a further aspect, the spent power fluid might be exhausted directly into a
formation the from which the target fluid is being taken, instead of bringing
it up to the
ground surface as shown in Figs. 21A and 21B.
A person skilled in the art will appreciate that there are various other
configurations in which a pump could be installed downhole, in addition to
those
described herein.
In some implementations it may be desirable to use more than one pump 1 (or
pump 601). Fig. 22 illustrates an aspect where three pumps 1A, lB and IC are
installed
in parallel in a casing 750 of a well to form a pump casing 752. Spacings 748
in between
the pumps 1A, 1B and IC can be used as fluid conduits for the supplied power
fluid,
exhausted power fluid and the pumped target fluid.
43
{E5796873.DOC;1 }
CA 02709048 2010-07-06
In this manner, a failure by one of the pumps IA, 1B or 1C will decrease the
amount of target fluid being pumped, but will not stop the flow of pumping
target fluid
completely.
Fig. 23 illustrates a further aspect, where a number of clusters 752A, 752B
and
752C, of parallel pumps 1A, lB and IC, are placed in series in a casing 750.
This can be
done to increase the total output of pumped target fluid or to provide
redundancy.
Extremely high temperature applications (such as e.g. Steam Assisted Gravity
Drainage processes or SAGD processes) and hostile environments require seal-
less
designs for reciprocating pumps. Fig. 24 illustrates a schematic illustration
of a prior art
reciprocating pump 801 in a seal-less configuration. The pump 801 has a
pumping piston
803 contained in a pumping cylinder 804 and an engine piston 805 contained in
an engine
cylinder 806. The pump piston 803 divides the pump cylinder 804 into a first
chamber
814 and a second chamber 815. Power fluid is alternately routed to either side
of the
engine piston 805 to drive the pump 801, with power fluid being routed to the
engine
cylinder 806 above the engine piston 805, to drive the engine piston 805 in a
downstroke
and then below the engine piston 805, to drive the engine piston 805 in an
upstroke.
A connecting rod 807 connects the pumping piston 803 to the engine piston 805.
As the engine piston 805 is driven through either an upstroke or a downstroke
by the
power fluid, the pumping piston 803 is forced into a corresponding downstroke
or
upstroke, respectively. With the pumping piston 803 driven through upstrokes
and
downstrokes, the pumping piston 803 draws in target fluid and then expels this
target
fluid from the pump cylinder 804 on both sides of the pumping piston 803. When
target
44
{E5796873.DOC;1 }
CA 02709048 2010-07-06
fluid is being drawn into the pump cylinder 804 on one side of the pumping
piston 803
because of the movement of the pump cylinder 804, target fluid is being
expelled from
the pump cylinder 804 on the other side of the pump piston 803.
Because the pump 802 is seal-less, annular gaps 811, 812 are present. The
annular gap 811 is present between the pump piston 803 and the pump cylinder
804 and
the annular gap 812 is present between the engine piston 805 and the engine
cylinder 806.
These gaps 811, 812 allow some fluid to by-pass the pump piston 803 and the
engine
piston 805.
Not only is the by-pass of some of the fluid unavoidable, but it is often
necessary.
Fluid passing between the pump piston 803 and the pump cylinder 804 and
passing
between the engine piston 805 and the engine cylinder 806 provides sealing and
hydraulic self-centering of the pump piston 803 and engine piston 805. The
hydraulic
self-centering is meant to prevent the pump piston 803 and engine piston 805
from
sticking to the pump cylinder 804 and engine cylinder 806, respectively, as
well as
reducing friction.
The power fluid in the engine cylinder 806 is relatively "clean", however,
with the
pump cylinder 804, the target fluid is often "dirty" (i.e. containing solid
contaminants).
These solid contaminants can affect the operation of the pump piston 803 by
increasing
the friction between the pump piston 803 and the pump cylinder 804 and even
damaging
the pump cylinder 803 as some of the dirty target fluid by-passes the pump
piston 803.
Fig. 24 illustrates the pump piston 803 in a discharge stroke where target
fluid is
being discharged from the pump cylinder 804 above the pump piston 803. The
{E5796873.DOC;1 }
CA 02709048 2010-07-06
movement of the pump piston 803 increases the pressure of the target fluid in
the first
chamber 814 defined by the pump piston 803 while causing the pressure of the
target
fluid in the pump cylinder 804 in the second chamber 815 defined by the pump
piston
803 to be decreased as the pump piston 802 travels through the downstroke. The
pressure
gradient between the first chamber 814 and the second chamber 815 causes some
of the
target fluid to migrate towards the second chamber 815 through the gap 811
between the
pump piston 803 and the pump cylinder 804. Any solids or abrasives in this
target fluid
can also be forced by the pressure into this gap 804.
When the pump piston 803 changes its direction of motion, and starts traveling
though an upstroke, the pressure gradient reverses and target fluid from the
second
chamber 815 can now be forced into the gap 811, which can cause a buildup of
solids and
abrasives in the gap 811 between the pump piston 804 and the pump cylinder
804.
Because the gap 811 often has very small clearances, the pump 901 can be
especially
susceptible to small particles of solids like sand.
For reciprocating pumps that operate in a similar manner to pump 801, when the
target fluid that will be pumped is "dirty" (i.e. containing solids and
abrasives) the pump
has to be retrofitted with additional flushing systems. However, this adds
complexity to
the pump and in some cases it is not always possible to add a flushing system
to a
reciprocating pump.
Referring to Figs. 1-4, the pump 1 does not require an additional flushing
system
to be operated in a seal-less configuration where the target fluid contains
solids and
abrasives because the pump 1 provides flushing as a result of the design.
46
{E5796873.DOC;1 }
CA 02709048 2010-07-06
Power fluid is introduced to the first chamber 12A and second chamber 12B
during the operation of the pump 1. Target fluid is drawn into the first
compression
chamber 1 1A and the second compression chamber 11B during the operation of
the pump
1. The power fluid is clean (free from solids, abrasives and other
contaminants) and is
under a higher pressure in the pump 1 than the target fluid causing the
pressure gradients
between the first chamber 12A and the first compression chamber 11A and the
second
chamber 12B and second compression chamber 11B to always be positive moving
towards the first chamber 12A and the second chamber 12B. This results in a
continuous
flush of clean power fluid around the first piston IOA and second piston IOB
towards the
first compression chamber 12A and the second compression chamber 12B,
respectively.
In this manner, some clean power fluid is continuously flushing past the first
piston 10A and second piston IOB into the first compression chamber 12A and
second
compression chamber 12B, sweeping away any solids and providing a built-in
flushing
action for the pump 1.
The same flushing of power fluid will occur in pump 601 shown in Figs 14-18
when pump 601 is operated in a seal-less configuration.
Fig. 25 illustrates centering mechanisms 1120 that can be provided on the
outside
surface of a piston 1110 to help center the piston 1110 when a pump 1101 is
operated in a
seal-less configuration. The pump 1101 can be a pump similar to pump 1 shown
in Figs.
1-4, pump 601 shown in Figs. 14-18 or some other similar pump being operated
in a seal-
less configuration.
47
{E5796873.DOC;1 }
CA 02709048 2010-07-06
A number of centering mechanisms 1120 can be provided on the outside surface
of the piston 1110 with each centering mechanisms 1120 having a slot 1122 and
a recess
1125. The slot 1122 can be a'relatively shallow depression in the piston that
can direct
fluid passing through the gap between a bore 1115 of the pump 1101 and the
piston 1110
to the recess 1125 of the centering mechanism 1120. The recess 1125 can form a
much
larger depression in the piston 1110 that can be sized and configured based on
the amount
of lateral force desired to center the piston 1110.
The centering mechanisms 1120 can operate on the hydrostatic bearing
principal.
When the piston 1110 is displaced from a concentric position in the bore 1115
of the
pump 1101, a rise in the mean pressure at the region of decreased clearance
between the
piston 1110 and the bore 1115 of the pump 1101 can occur as a result of fluid
being
directed into the centering mechanisms 1120. Additionally, a fall in the mean
pressure at
the region of increased clearance between the piston 1110 and the bore 1115
can also
occur. This increase in pressure at the region of decreased clearance and
corresponding
decrease in pressure at the region of increased clearance can cause an overall
centering
force on the piston 1110 tending to center the piston 1110 in the bore 1115 of
the pump
1101.
This centering of the piston 1110, aided by the centering mechanisms 1120 can
help to prevent the contact of the piston 1110 with the bore 1115, reduce
friction acting
on the piston 1110, reduce leakage (bypass) of the fluid past the piston 1110,
etc.
Referring again to Figs 1-4, when the pump 1 is used in a "seal"
configuration, the
pressure gradient between the first compression chamber 11A and the first
chamber 12A
48
{E5796873.DOC;1 }
CA 02709048 2010-07-06
and the pressure gradient between the second compression chamber 11B and the
second
chamber 12B in pump 1 can be beneficial to the seals. These same pressure
gradients are
present in the pump 601 shown in Figs. 15-19.
Fig. 26 is a schematic illustration of a prior art reciprocating pinup 901. An
engine piston 905 is provided in an engine cylinder 906. A pump piston 903 in
a pump
cylinder 904 defines a first pump chamber 914 and a second pump chamber 915.
The
pump piston 903 reciprocates in the pump cylinder 904 to alternately draw in
and
discharge target fluid from the first pump chamber 914 and the second pump
chamber
915 to pump the target fluid. A seal 909, which is typically an elastomer
seal, is provided
around the pump piston 903 to fluidly separate the first pump chamber 814 and
the
second pump chamber 815. When target fluid is being discharged from the first
pump
chamber 814, the pressure of the target fluid in the first chamber 814 acts
against the seal
909 and places a force on the seal 909 acting away from the first pump chamber
814
because the pressure of the target fluid in the first chamber 815 will be
significantly
greater than the pressure of the target fluid in the second chamber 815.
Additionally, a
friction force also acts on the seal 909 in the same direction as the force
acting on the seal
909 by the pressure of the target fluid in the first chamber 814. When the
pump piston
803 reverses direction, a force is applied to the seal 909 in an opposite
direction by the
pressure of the target fluid in the second chamber 815 and a friction force is
also applied
to the seal 909 in the same direction as the force applied by the pressure of
the target fluid
in the second chamber 815. The force from the pressure of the target fluid and
the force
of friction act in the same direction resulting in combined forces acting in a
single
direction on the seal 909 that is opposite to the direction of movement of the
pump piston
49
{E5796873.DOC;1 }
CA 02709048 2010-07-06
903. This combination of forces in a single direction opposite to the
direction of motion
of the pump piston 903 can cause the seal 909 to be dragged between the pump
piston -
803 and the pump cylinder 904 (extruded) reducing the life and compromising
the
reliability of the seal 909.
Although the forces are not as great, the same effects can occur for the seal
908
encircling the engine piston 905.
Fig. 27 is a schematic illustration of a pump 1001 during the discharge of
target
fluid from the first end 1003 of the pump 1001. Pump 1001 is shown with
similar
element to pump 1 shown in Fig. 1-4, however, a person skilled in the art will
appreciate
that pump 601 shown in Figs. 15- 19 could also be used with seals. The pump
1001 has a
first piston 1010A and a second piston 1010B. The first piston 1010A divides a
first
compression chamber 1011A from a first chamber 1012A and the second piston
1010B
divides a second compression chamber 1011B from a second chamber 1012B. A
first
sealing ring 1009A is provided encircling the first piston 101 OA and a second
sealing ring
1009B is provided encircling the second piston 1010B.
When the first piston 1010A is being driven through a discharge stroke, the
pressure exerted on the first seal 1009A by the target fluid in a first
compression chamber
1011A is less than the pressure exerted on the first seal 1009A by the power
fluid in the
first chamber 1012A because the pressure of the power fluid driving the first
piston
1010A is higher than the pressure of the target fluid being discharged from
the first
compression chamber 1011A. The force acting on the first sealing ring 1009A as
a result
of the higher pressure of the power supply fluid acts in the same direction as
the motion
{E5796873.DOC;1 }
CA 02709048 2010-07-06
of the of the first piston 1010A. The same forces occur on the second seal
1009B when
the second piston 1010B is being driven through a discharge stroke.
In this manner, the pressure differential between the first compression
chamber
11A and the first chamber 12A or the second compression chamber 11B and the
second
chamber 12B during a discharge stroke of the first piston 1 OA or second
piston l OB, acts
in the direction of movement of the piston, reducing the likelihood of the
first seal 1009A
or second seal 1009B being extruded or damaged during operation of the pump
1001.
Fig. 28 through 30 illustrate a porting mechanism that can be used to
selectively
allow and prevent a flow of fluid from passing around a sealing ring. A pair
of sealing
rings 1212, 1214 can be provided in conjunction with a groove 1220. As shown
in Fig.
29, the groove 1220 can, in one aspect, have a side profile wherein the groove
1220 is
wider at the top of the groove 1220 tapering narrower towards the bottom of
the groove
1220. In one aspect, the edges of the groove 1220 can be slightly rounded as
the groove
1220 tapers towards a bottom of the groove 1220. As shown in Fig. 30, the
groove 1220
can have ends 1222, 1224 that converge into narrower widths, with a middle
section of
the groove 1220 having the widest width. In one aspect, a gear cutter can be
used to form
the grooves 1220.
The groove 1220 can be used to allow a fluid entering through a inlet port
1230 to
by-pass one of the sealing rings 1212 as shown in Fig. 28. When one of the
sealing rings
1212 is slid over the groove 1220 as shown in Fig. 28, fluid can pass around
the sealing
ring 1212 by entering the groove 1220 and passing around the sealing ring
1212. The
other sealing ring 1214, which is not shown placed over the groove 1220 in
Fig. 28, will
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CA 02709048 2010-07-06
block the flow of fluid past the other sealing ring 1214. The sliding of the
sealing ring
1212 over the groove 1220 can reduce or avoid the shearing force that is
placed on
sealing rings when sealing rings are slid across a more conventional cross-
drilled port,
rather than the groove 1220.
Referring to Figs. 1-4, the reciprocating movement of the reversing sleeve 6
is
accompanied by the opening and closing of the housing inlet ports 8A, 8B and
the
housing outlet ports 9A, 9B. Housing outlet ports 9A, 9B open when they align
with the
reversing sleeve exhaust ports 19A, 19B, respectively. A groove 1220, as shown
in Figs.
28-29, could be used with the these ports or other ports in the various pumps
discussed
herein.
Additionally, grooves, similar to grooves 1220 shown in Figs. 29 and 30, can
be
used to equalize pressure across a sealing ring as the sealing ring is moved
across a port
and before the sealing ring reaches the other side of the port. Figs. 31-33
illustrate
grooves 1320 being used to equalize pressure across sealing rings 1312, 1314
as the
sealing rings 1312, 1314 move across first and second ports 1342, 1344
connected to the
grooves 1320.
A fluid introduced through a first inlet 1330 can be directed to either a
first port
1342 or a second port 1344 depending on the position of a spool 1350. When the
second
port 1344 is open, the sealing rings 1312, 1314 can be placed on either side
of the second
port 1344, allowing fluid from an inlet port 1330 to flow into the second port
1344, as
shown in Fig. 31. As the spool 1350 moves, moving the first port 1342 towards
the inlet
port 1350, the sealing rings 1312, 1314 can slide across the outer surface of
the spool
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CA 02709048 2010-07-06
1350. Rather than simply crossing over a cross-drilled port, when one of the
sealing
rings 1312 reaches the first port 1342 with a groove 1320 provided at the
opening of the
port 1342, the sealing ring 1312 can pass over the groove 1320. When the
sealing ring
1312 is positioned substantially over the groove 1320 and the first port 1342,
as shown in
Fig. 32, fluid from the inlet port 1330 can enter the groove 1320. Some of the
fluid that
enters the groove 1320 can then enter the port 1342, while some of the fluid
can pass
around the sealing ring 1312 through the groove 1320 to try and equalize the
pressure on
either side of the sealing ring 1312. As the spool 1350 continues to move, the
sealing
ring 1312 will eventually cross over the first port 1342 and the groove 1320
and the first
port 1342 will not be fully opened, with the sealing rings 1312 preventing
fluid from
passing around it. Directing the fluid from the inlet port 1330 into the fist
port 1342.
Again, these grooves 1320 can be used with a number of suitable pumps. In one
aspect they can be used with pump 1 shown in Figs. 1-4, pump 601 shown in
Figs. 14-18
or any other suitable pump.
The previous description of the disclosed embodiments is provided to enable
any
person skilled in the art to make or use the present invention. Various
modifications to
those embodiments will be readily apparent to those skilled in the art, and
the generic
principles defined herein may be applied to other embodiments without
departing from
the spirit or scope of the invention. Thus, the present invention is not
intended to be
limited to the embodiments shown herein, but is to be accorded the full scope
consistent
with the claims, wherein reference to an element in the singular, such as by
use of the
article "a" or "an" is not intended to mean "one and only one" unless
specifically so
stated, but rather "one or more". All structural and functional equivalents to
the elements
53
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CA 02709048 2010-07-06
of the various embodiments described throughout the disclosure that are known
or later
come to be known to those or ordinary skill in the art are intended to be
encompassed by
the elements of the claims. Moreover, nothing disclosed herein is intended to
be
dedicated to the public regardless of whether such disclosure is explicitly
recited in the
claims.
54
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