U.S. patent application number 10/370207 was filed with the patent office on 2004-08-19 for flexible hose apparatus.
Invention is credited to Harris, Richard K..
Application Number | 20040161347 10/370207 |
Document ID | / |
Family ID | 32850395 |
Filed Date | 2004-08-19 |
United States Patent
Application |
20040161347 |
Kind Code |
A1 |
Harris, Richard K. |
August 19, 2004 |
Flexible hose apparatus
Abstract
Described is a drive assembly (20) and a production assembly
(22) for use in producing reciprocating motion. In one embodiment,
the drive assembly is formed as a flexible hose hydraulic cylinder
that uses a source of fluid pressure to extend and retract a
flexible hose. One or more valves are available to regulate the
pressure within the flexible hose. A reciprocating member is
connected to the flexible hose. Extension and retraction of the
hose cause corresponding translation in the reciprocating member.
In one embodiment, the reciprocating member is a piston rod that is
biased in one direction.
Inventors: |
Harris, Richard K.;
(Kirkland, WA) |
Correspondence
Address: |
CHRISTENSEN, O'CONNOR, JOHNSON, KINDNESS, PLLC
1420 FIFTH AVENUE
SUITE 2800
SEATTLE
WA
98101-2347
US
|
Family ID: |
32850395 |
Appl. No.: |
10/370207 |
Filed: |
February 19, 2003 |
Current U.S.
Class: |
417/330 |
Current CPC
Class: |
F04B 9/12 20130101; F01B
19/04 20130101; F15B 15/103 20130101 |
Class at
Publication: |
417/330 |
International
Class: |
F04B 017/00 |
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A drive assembly for producing reciprocal motion, a source of
fluid pressure being provided to the drive assembly, the assembly
comprising: (a) a flexible hose capable of holding a pressurized
fluid; (b) a housing within which the hose is disposed; and (c) at
least one valve operable to selectively allow pressurized fluid to
enter the flexible hose, the at least one valve further operable to
vent pressure from the hose; and (d) a reciprocating member
connected to the flexible hose; wherein, during use, fluid pressure
is supplied to the flexible hose via the at least one valve,
thereby increasing the internal pressure in the flexible hose and
causing the flexible hose to extend and the reciprocating member to
translate; and wherein, during use, the at least one valve vents
pressure from the flexible hose causing the flexible hose and
reciprocating member to return to their retracted positions.
2. The drive assembly according to claim 1, wherein the
reciprocating member is a piston rod having a retracted position
and an extended position, the piston rod being biased in the
retracted position.
3. The drive assembly according to claim 2, wherein the flexible
hose is made of a nonexpandable material.
4. The drive assembly according to claim 2, wherein the flexible
hose is formed of a nonpermeable flexible woven fabric.
5. The drive assembly according to claim 2, wherein the flexible
hose is formed in an accordion shape.
6. The drive assembly according to claim 5, wherein the
accordion-shaped flexible hose is made of a material having at
least one component of metal.
7. The drive assembly according to claim 5, wherein the
accordion-shaped flexible hose is made of at least one of a rubber
material, a synthetic material, and a fabric material.
8. The drive assembly according to claim 1, wherein the at least
one valve is a three-way valve capable of providing both positive
fluid pressure and relief of fluid pressure within the flexible
hose.
9. The drive assembly according to claim 1, wherein the at least
one valve includes two two-way valves that cooperate to provide
positive fluid pressure and relief of fluid pressure within the
flexible hose.
10. The drive assembly according to claim 2, wherein the fluid
pressure is a hydraulic fluid pressure.
11. The drive assembly according to claim 2, wherein the
pressurized fluid used to enter the flexible hose is provided from
a column of fluid having an associated head pressure.
12. The drive assembly according to claim 2, wherein the drive
assembly includes a spring and the piston rod includes a proximal
end attached to the flexible hose, the spring being held in
compression between the flexible hose and the housing and urging
the piston rod to its retracted position.
13. The drive assembly according to claim 12, wherein the spring is
a coil spring wrapped around the piston rod.
14. The drive assembly according to claim 12, further comprising a
production assembly including a production chamber located adjacent
the housing and into which the piston rod extends.
15. The drive assembly according to claim 2, further comprising a
production assembly including a production chamber located
proximate the housing and into which the piston rod extends.
16. The drive assembly according to claim 2, further comprising a
production assembly including a production chamber capable of
holding a fluid, the production chamber including at least one
fluid entry port for entry of external fluid; wherein the
production assembly includes a production piston connected to a
distal end of the piston rod and located within the production
chamber; the production assembly including a valve; wherein, as the
piston rod moves from its retracted position to its extended
position, the production piston forces fluid out of the production
chamber; simultaneous with this movement is the drawing of external
fluid into the production chamber through an at least one fluid
entry port located in the production chamber; wherein, as the
piston rod moves from its extended position to its retracted
position, the production piston moves back through the production
chamber and external fluid passes through the valve in preparation
for the next production stroke.
17. The drive assembly according to claim 16, wherein the at least
one fluid entry port allows fluid to enter the production chamber
but not to exit the production chamber, thereby ensuring passage of
fluid from the production chamber through the production piston
during the return stroke.
18. The drive assembly according to claim 16, wherein the
production chamber includes a distal valve that allows fluid to
exit the production chamber during the extend stroke but not to
enter the production chamber, thereby ensuring passage of fluid
from the production chamber through the production piston during
the return stroke.
19. The drive assembly according to claim 16, wherein the at least
one valve includes a valve to selectively allow pressurized fluid
to enter the flexible hose and another valve to vent pressure from
the flexible hose.
20. The drive assembly according to claim 16, wherein the at least
one fluid entry port includes multiple openings located along the
sides of the production chamber.
21. The drive assembly according to claim 16, wherein the housing
is a guide chamber located adjacent the production chamber, the
guide chamber holding the drive assembly, the piston rod extending
between the guide chamber and the production chamber through a
passageway extending therebetween.
22. The drive assembly according to claim 21, wherein the drive
assembly includes a spring located within the guide chamber, the
spring being held in compression between the flexible hose and the
guide chamber and urging the piston rod into the guide chamber.
23. The drive assembly according to claim 22, wherein the spring is
a coil spring wrapped around the piston rod.
24. The drive assembly according to claim 16, wherein the drive
assembly is adapted for use with a production conduit, the drive
assembly being immersed in a source of external fluid, a source of
fluid pressure being provided to the flexible hose, during the
extend stroke, the production piston forcing fluid out of the
production chamber and into the production conduit.
25. The drive assembly according to claim 24, wherein the
pressurized fluid used to enter the flexible hose is provided from
a column of fluid having an associated head pressure.
26. The drive assembly according to claim 25, further comprising a
fluid return path connected between the production conduit and the
at least one valve to selectively allow pressurized fluid to enter
the flexible hose, the column of fluid thus being provided from the
production conduit.
27. The drive assembly according to claim 24, wherein the
pressurized fluid used to enter the flexible hose is provided from
a secondary pressurized fluid source.
28. The drive assembly according to claim 24, wherein the fluid
used to drive the flexible hose includes at least one of fresh
water, oil, and saltwater.
29. The drive assembly according to claim 24, wherein the fluid
used to drive the flexible hose is a free flowing fluid.
30. In a device having a reciprocating member, an improvement
comprising a flexible hose connected to the reciprocating member to
drive the reciprocating member in at least one direction, the
flexible hose being formed of a nonexpandable material, the
flexible hose being capable of accepting and releasing pressure of
an incompressible fluid in order to move between extended and
retracted states.
31. In a device having a reciprocating member, an improvement
comprising a flexible hose connected to the reciprocating member to
drive the reciprocating member in at least one direction, the
flexible hose being formed of a nonexpandable material made in an
accordion shape, the flexible hose being capable of accepting and
releasing pressure of an incompressible fluid in order to move
between extended and retracted states.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to pumps and, more
particularly, to hydraulic cylinders that produce reciprocal
motion.
BACKGROUND OF THE INVENTION
[0002] There are currently a number of different types of hydraulic
cylinders that utilize an essentially incompressible fluid to drive
a piston in a reciprocating manner. These cylinders are typically
used to drive mechanical devices in a reciprocal linear or rotary
motion. In general, such cylinders require movement of hydraulic
fluid that is proportional to the size and stroke of the piston. A
pressure source, such as a pump that is driven by an electric or
internal combustion motor, is used to deliver the hydraulic fluid
to the cylinder.
[0003] One of the disadvantages of known hydraulic cylinders is the
inefficiency between the amount of energy required to move the
piston and the amount of energy delivered to the driven mechanical
device. As such, a need exists for a hydraulic cylinder that is
more efficient, and particularly one that requires a reduced amount
of energy to drive the piston than is generally found. The present
invention is directed to fulfilling these needs and others as
described below.
SUMMARY OF THE INVENTION
[0004] The present invention is directed to a pumping mechanism
having a number of unique aspects. In one embodiment, the drive
assembly includes a flexible hose capable of holding a pressurized
fluid, a housing for supporting the hose, one or more valves to
regulate pressure within the flexible hose, and a production
assembly including a reciprocating member connected to the flexible
hose. By inputting fluid pressure into the flexible hose, it
extends and accomplishes a production stroke. The extension of the
hose causes the reciprocating member to translate. Venting pressure
from the flexible hose allows the flexible hose and reciprocating
member to return to their initial positions. The translation of the
reciprocating member may also be used to drive other components in
a linear or rotary manner. Various other arrangements are described
that make use of the flexible hose hydraulic cylinder and fluid
pressure design. As will be appreciated upon reading the following,
the flexible hose hydraulic cylinder may be used for driving
various types of mechanical devices, such as crankshafts,
mechanical arms, lifting mechanisms, and pumps.
[0005] In accordance with aspects of this invention, in one
embodiment, a drive assembly includes a tubular chamber with fixed
ends and a flexible hose that is positioned inside the tubular
chamber. One end of the flexible hose is attached to one end of the
tubular chamber, and the other end of the flexible hose is attached
to a piston rod. The piston rod slides through a passageway in the
second, fixed end of the tubular chamber. The flexible hose piston
assembly is biased in a retracted position by a coiled spring. A
source of fluid pressure introduced to the flexible hose piston
causes the flexible hose piston to extend and drive the piston
assembly in an outward direction.
[0006] In accordance with other aspects, in one embodiment, a
production piston is attached to the distal end of the piston rod
and is used to push fluid from a production chamber. As the piston
rod moves from its retracted to its extended position, the
production piston forces fluid out of the production chamber. In
one embodiment and simultaneous with this movement, is the drawing
of external fluid into the production chamber through a fluid entry
port in the chamber. As the piston rod moves from its extended to
its retracted position, the production piston moves back through
the production chamber. External fluid passes through a valve in
the production piston in order to fill the outer regions of the
chamber in preparation for the next production stroke.
[0007] In accordance with still further aspects, in one embodiment,
a column of fluid head pressure provides the fluid pressure to the
hydraulic cylinder. In another embodiment, the apparatus is
immersed in a body of fluid and the production chamber is in fluid
communication with a production conduit. Head pressure in the
conduit drives the drive assembly, while the conduit also provides
an outlet for the pumped fluid. This arrangement results in only a
minimum amount of energy needed to raise a substantial amount of
fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The foregoing aspects and many of the attendant advantages
of this invention will become more readily appreciated by reference
to the following detailed description, when taken in conjunction
with the accompanying drawings, wherein:
[0009] FIG. 1 is a cross-sectional schematic side view of one
embodiment of a flexible hose hydraulic cylinder formed in
accordance with the present invention;
[0010] FIG. 2 is a cross-sectional schematic side view of another
embodiment of a flexible hose hydraulic cylinder formed in
accordance with the present invention;
[0011] FIG. 3 is a cross-sectional side view of yet another
embodiment of a flexible hose hydraulic cylinder attached to a
production assembly and in a retracted position, both formed in
accordance with the present invention;
[0012] FIG. 4 is a cross-sectional side view of the device of FIG.
3, shown in an extended position;
[0013] FIG. 5 is a cross-sectional side view of still another
embodiment of a flexible hose hydraulic cylinder attached to a
production assembly and in an extended position, both formed in
accordance with the present invention;
[0014] FIG. 6 is a cross-sectional schematic side view of another
embodiment of a flexible hose hydraulic cylinder attached to a
production assembly in a retracted position, both formed in
accordance with the present invention;
[0015] FIG. 7 is a cross-sectional side view of an alternative
production assembly formed in accordance with the present
invention; and
[0016] FIG. 8 is a cross-sectional schematic side view of a
dual-hose drive assembly formed in accordance with the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] The present invention is a pumping mechanism having a number
of unique aspects that may be used separately or in combination to
result in improved pumping efficiencies. In general, described
below are two main aspects--a drive assembly 20 and a production
assembly 22. The drive assembly is also referred to herein as a
"flexible hose hydraulic cylinder" or, simply, "hydraulic
cylinder". The drive assembly 20 provides a power stroke, while the
production assembly 22 uses the stroke to accomplish some specific
reciprocating work. FIGS. 1, 2, and 8 illustrate various
embodiments of a flexible hose hydraulic cylinder. FIGS. 3-7
illustrate specific embodiments of a production assembly that take
advantage of a hydraulic cylinder stroke. As will be appreciated
upon reading the materials, there are numerous configurations
possible using these teachings.
[0018] Referring to FIGS. 1 and 2, the flexible hose hydraulic
cylinder 20 is arranged to produce a reciprocating motion. In these
embodiments, the cylinder 20 includes a flexible tube or hose 24, a
guide chamber 26, a pushing plate 28, an optional biasing member
30, and one or more valves 32. The pushing plate moves in a linear
manner and places a force against an adjoining object. In this way,
the pushing plate itself is a type of "piston", unique to this
invention. A source of fluid pressure is provided to the cylinder,
such as from an incompressible fluid, e.g., hydraulic fluid, water,
etc. The term "incompressible fluids" means those fluids that are
absolutely incompressible as well as those that are essentially or
substantially incompressible. The amount of compression permissible
may depend on the particular circumstances in which the apparatus
is being used.
[0019] In FIG. 1, the hose 24 has a tubular shape. In FIG. 2, the
hose has an accordion shape. In both instances, the hose is
preferably made of a flexible, though nonexpandable, material.
Example materials include, but are not limited to, a synthetic, a
natural or manmade rubber, a thermal plastic, a high-strength
bidirectional fabric (e.g., aramid bidirectional fabric),
Kevlar.TM., and others. The rubber or other material may be
reinforced by fabric or fibres, such as carbon fibres. Further, in
some embodiments, the hose may include a metal material component.
As used herein, the term "nonexpandable material" includes those
materials that are absolutely nonexpandable as well as those that
are essentially or substantially nonexpandable. The amount of
expansion permissible may depend on the particular circumstances in
which the apparatus is being used.
[0020] The hose 24 further includes a first end 40 closed off by
the pushing plate and a second end 42 anchored to the guide chamber
or other support structure. Alternatively, the flexible hose 24 may
include a middle pushing plate 44, thereby allowing both ends of
the drive assembly to produce a production stroke. See, for
example, FIG. 8, in which two flexible hoses are positioned end to
end and are arranged to operate in alternative fashion. A piston
rod 50 or other energy transmitting component is attached to, or in
communication with, a moving end of the flexible hose 24. In FIGS.
1 and 2, the flexible hose hydraulic cylinder is housed and
supported within the guide chamber 26, the second end of the hose
being fixedly attached to the bottom of the chamber. An opening 52
at the top of the chamber provides a passageway through which the
piston rod 50 may extend. In FIG. 8, the hoses are positioned
within a guide chamber and an elongated piston rod 50 is connected
to the middle support member that divides the hoses. The rod 50
extends out of the opening 52 at one end of the chamber 26. Various
seals and sealants may be used throughout. (See, for example, FIG.
6, item 53.)
[0021] In some embodiments, a biasing member may be used to push
the piston rod 50 and flexible hose 24 to a desired position.
Various types of biasing methods are known and may be incorporated
into the present invention. For example, FIGS. 1 and 2 show a coil
spring 54 held in compression between the upper wall of the guide
chamber and the top surface of the pushing plate 28. The spring 54
continuously pushes the piston rod 50 toward its retracted
position.
[0022] During use, the flexible hose 24 moves the piston rod 50
between extended and retracted positions in response to the
pressure within the flexible hose. This is accomplished using one
or more valves that selectively allow pressurized fluid to enter
and exit the flexible hose. There are many different combinations
of valves that can be used to accomplish these tasks.
[0023] In the embodiments of FIGS. 1, 2, 6, and 8, a single
three-way valve 56 fills and relieves fluid pressure in the
flexible hose 24. When filled, the internal pressure in the
flexible hose 24 causes the hose to extend. In doing so, it pushes
the piston rod 50 outward. Turning valve 56 to its second position
relieves pressure from the flexible hose 24, which results in the
rod 50 returning to its retracted position by force of the biasing
member 30. In the embodiments of FIGS. 3, 4, 5, and 7 separate
two-way valves (items 58 and 60) are used to fill and relieve fluid
pressure.
[0024] Referring to the embodiment of FIGS. 3 and 4, the production
assembly 22 is adapted to push fluid out of a production chamber 70
and into a production conduit 72. The production chamber 70 is an
enclosed volume capable of holding a desired amount of fluid. The
production chamber 70 is in fluid communication with the lower end
of the production conduit 72, though separated by a wall having a
first one-way valve 74. In the embodiment of FIG. 3, a fixed plug
76 is positioned near the top of the production chamber 70 and a
series of holes 78 are drilled through the plug 76 to allow fluid
to pass through the plug. The first one-way valve 74 is a flapper
valve that releases fluid into the production conduit 72 during the
production stroke.
[0025] Still referring to FIGS. 3 and 4, the piston rod 50 is
located in a generally upright orientation and includes a proximal
end and a distal end. A production piston 84 is connected to the
proximal end of the piston rod 50. The production piston 84 is
located within the production chamber 70, preferably in a sealed
relationship with the inner surfaces of the production chamber side
walls 70.
[0026] One or more external fluid entry ports 86 are located in the
production chamber 70 at a location below the production piston 84.
Ports 86 are in fluid communication with a source of static fluid,
such as water in a ground well. The production piston 84 is located
between the fluid entry ports 86 and the first one-way valve 74.
When the production piston 84 is in a retracted position, it is
located closer to the ports 86. When the production piston 84 is in
an extended position, it is located closer to the first one-way
valve 74. The ports 86 allow fluid to be drawn into the production
chamber 70 during the production stroke. FIG. 7 illustrates an
alternative method of inputting fluid into the production chamber
70 in which the fluid entry ports 86 are made through the upper
wall of the guide chamber 26 and into the lower end of the
production chamber 70.
[0027] Referring back to FIGS. 3 and 4, a second one-way valve 90
is located at the production piston, thereby permitting fluid to
travel in an outward direction. In one arrangement, the second
one-way valve 90 is a rubber flapper valve fitted over a series of
holes drilled through the production piston 84. The flapper is
located on the external side surface of the production piston 84.
The holes and valve allow fluid to pass into the production chamber
70, through the production piston 84 when the production piston 84
is moving from its extended position to its retracted position.
[0028] The guide chamber 26 is located adjacent the production
chamber 70. In the embodiment shown, these chambers 70 and 26 are
connected to one another with the piston rod 50 extending
therebetween. The guide chamber 26 is an upright enclosure having
an upper end and a lower end. The upper end includes the passage 52
for holding the piston rod 50 and supporting it therein during
reciprocation. In this embodiment, the flexible hose 24 is a
flexible tube with a lower end fixedly attached to the bottom of
the guide chamber 26. FIG. 5 shows a similar arrangement with the
flexible hose 24 formed in an accordion or bellows shape. The guide
chamber 26 may be open to the surrounding fluid source.
[0029] As described with reference to FIGS. 1 and 2, the drive
assembly 20 of FIGS. 3 and 4 includes the flexible hose 24, which
is in communication with a source of pressure. During use, the
flexible hose 24 pushes against the distal end of the piston rod 50
so that reciprocating motion of the flexible hose 24 causes similar
reciprocating motion of the production piston 84. In this manner,
the device may be used to easily move fluid from one elevation to a
second, higher elevation.
[0030] As stated above, the piston rod and drive assembly have a
retracted position (see FIG. 3) and an extended position (see FIG.
4). In the embodiment shown, these assemblies are biased in the
retracted position by a compressed coil spring 54 surrounding the
production piston rod 50. The spring 54 extends between the upper,
inner surface of the guide chamber 26 and the upper, outer surface
of the flexible hose 24.
[0031] A relief valve 60 is connected to the upper end of the
flexible hose 24. The relief valve relieves fluid pressure from the
interior of the flexible hose 24 via a relief passage 102. A fluid
return path 104 extends between the production conduit 72 and a
head pressure fluid entry port 106 in the guide chamber 26. A third
valve 58 is provided at the fluid entry port 106. The third valve
58 selectively allows fluid pressure to alternately be opened or
closed from entering the fluid return path 104 into the flexible
hose 24. Example valves that may be used are two-way electrical
valves, pneumatic valves, manual valves, etc. The optimal valve
type will depend on the particular application. In alternative
embodiments, placements of the third valve 58 and the relief valve
60 may be switched. Alternatively, these components may both be
placed on top of the flexible hose 24, or both could be located on
the bottom of the flexible hose 24. The fluid entry port 106 and
the fluid return path 104 would change locations
commensurately.
[0032] Fluid is pumped by opening the third valve 58. When this
happens, fluid pressure from the fluid return path 104 is permitted
to enter into the flexible hose 24, thus causing the flexible hose
24 to extend fully. In doing so, the upper end of the flexible hose
24 drives the production piston and rod, 84 and 50, respectively,
upward, against the compressive force of the biasing spring 54. In
general, the diameter of the flexible hose is larger than the
diameter of the production piston 84 in order to overcome the
various forces acting on the piston 84.
[0033] Upward movement of the production piston 84 causes fluid in
the production chamber 70 to flow out of the chamber 70 and into
the production conduit 72. In the embodiment of FIG. 3, the fluid
flows through the first one-way valve 74. In the embodiment of FIG.
7, fluid flows through the ball valve 126. During this upward
movement, the second one-way valve 90 is closed. Driving the
production piston 84 upward causes fluid within the production
conduit 72 to spill out of its upper end. Simultaneous with fluid
moving out of the production chamber 70 is the inward flow of
external static fluid into the production chamber 70 through the
fluid entry ports 86. In creating an arrangement for a particular
application, the flexible hose 24 should have a piston area of
sufficient size that when pressurized, the force generated is
greater than the combined forces of the head pressure pushing
against the production piston 84, the biasing spring 54, and any
friction. In this way, the force generated by the flexible hose is
always greater than the opposing forces during the intended
production stroke.
[0034] Once the production piston 84 has reached the end of its
stroke, the third valve 58 is closed, completely shutting off head
pressure in the fluid return path 104 to the flexible hose 24. The
two-way relief valve 60 is momentarily opened to vent pressure in
the flexible hose 24. In doing so, biasing spring 54 expands and
drives the production piston 84 downward toward its retracted
state. The outflow of fluid pressure from the flexible hose 24
enables it to return to its original serpentine, coiled, or other
folded configuration. The elimination of pressure should be to an
extent necessary to allow movement of the flexible hose 24 to its
retracted state. During this movement, the second one-way valve 90
allows the newly entered external static fluid to move through the
production piston 84 and into the upper regions of the production
chamber 70. Fluid in the production conduit 72 is prohibited from
reentering the production chamber by the orientation of the first
one-way valve 74.
[0035] In the retracted position, the production piston 84 is
located just above the fluid entry ports 86. A stop ledge 110 may
be used on the piston rod 50 (or alternatively along the production
chamber walls) to prohibit the production piston 84 from moving
below the ports 86. In the retracted position, the third valve 58
is closed. The production chamber 70, the production conduit 72,
and the fluid return path 104 are each filled with fluid. A maximum
head pressure is felt at the third two-way valve 58. The flexible
hose 24 is in a flexed state, and the two-way relief valve 60 is
closed.
[0036] Pressure to drive the drive assembly may be provided from
various sources. In the embodiment of FIG. 3, fluid head pressure
available in the production conduit 72 via the fluid return path
104 is used to move the drive assembly. Thus, during use, the
production conduit 72 should be filled enough to provide sufficient
head pressure to the drive assembly. In another embodiment,
pressure is provided from a pressurized vessel having a pressurized
gas over fluid. In such an arrangement, the fluid may need to be
replenished periodically. As will be appreciated by those skilled
in the art, the invention can use any number of pressure means as a
way to fully extend the flexible hose 24.
[0037] As will also be appreciated from a reading of the above,
using the present invention to raise a column of fluid has a number
of distinct advantages. The drive assembly itself performs as a
piston, while requiring only a very small movement of fluid within
the flexible hose. When sufficient pressure is introduced into the
flexible hose 24 by opening the third valve 58, the head pressure
in the column of liquid is introduced to the flexible hose 24. The
hose 24 then straightens and moves in an upward direction, causing
the production piston 84 to move similarly. When the hose 24 has
reached the end of the stroke, the third valve 58 is closed,
shutting off the head pressure to the hose 24. When the pressure is
released from the flexible hose 24 by opening the relief valve 60,
the flexible hose 24 returns to its unextended state from the
pushing force of the compressed coil spring 54. Because fluid is
essentially incompressible and because the flexible hose 24 is
constructed of minimally expanding materials, only a very small
amount of fluid is lost when the pressure is released. The spring
force required to reset the flexible hose 24 is that force
necessary to overcome the friction in the seals and to overcome the
resistance of the flexible hose 24 to return to its unextended
configuration.
[0038] Using only one conduit for both power and production has
benefits as well. Simpler and more efficient construction is
possible, which enables the return of the small amount of fluid
lost in the flexible hose when pressure is released from the
flexible hose. The energy required to operate the device is
essentially the energy used to open and close the relief valve and
the third valve. These energy requirements remain essentially the
same, regardless of how high the column of fluid happens to be.
Therefore, the higher the head, the more efficient the device
becomes. Other known pumps using a column of fluid as a power
source all have similar problems--they either have to raise two
volumes of fluid and use one volume to reset the piston, or they
have to increase the pressure on the power side equal to the force
to lift one volume of fluid to the surface. Therefore, there is no
saving of energy in these prior art devices.
[0039] FIG. 6 illustrates an embodiment of a drive assembly and
production assembly for use in lifting sucker rods in fluid wells.
Instead of using the extended position of the piston rod 50 to
define the production stroke, the piston rod 50 is connected to the
hydraulic cylinder 20 such that extension of the flexible hose 24
causes retraction of the piston rod 50. In this embodiment, the
piston rod 50 is elongated to pass through the hose 24 and to
extend the length of the hose when pressurized. The result is that
the hydraulic cylinder 20 pulls the rod 50 inward, into the hose
24, in order to draw fluid from a source. The combined weight of
the piston rod 50 and the sucker rods returns the flexible hose 24
to its bent position once pressure is relieved in the flexible
hose.
[0040] FIG. 7 illustrates an alternate method of biasing the
device. Other methods may be used as well. In FIG. 7, an elongated
reset tube 120 extends from the exterior side surface of the
production piston 84. The reset tube 120 includes an inner delivery
channel 122. A series of openings 124 are provided at the base of
the reset tube 120 and provide fluid communication between the
production chamber 70 and the delivery channel 122. The opposite
end of the reset tube 120 includes a ball check valve or other
one-way valve 126. The openings 124 and valve 126 allow fluid in
the production chamber 70 to flow into the channel 122, out of the
reset tube 120, and into the production conduit 72 during the
production stroke. The reset tube 120 passes through the wall or
plug 76 that separates the production chamber 70 from the
production conduit 72. The valve 126 is located in the production
conduit 72 at all times. Once the production stroke is complete and
pressure is relieved from the flexible hose 24, head pressure on
the valve 126 is sufficient to reset the production piston 84 to
its retracted position. (Head pressure is generally defined as the
fluid force or pressure present at the lower end of a fluid column,
calculated as fluid density times column height times the
gravitational constant, g.)
[0041] In an alternative embodiment, the flexible hose has a length
of approximately 10 feet with a stroke in the range of about 5 to 6
inches. In another embodiment, the hose is nominally formed in a
coil shape to increase the stroke length.
[0042] While the preferred embodiment of the invention has been
illustrated and described, it will be appreciated that various
changes can be made therein without departing from the spirit and
scope of the invention. For example, the mechanisms are shown in an
upright orientation. They may also be oriented laterally and still
work effectively for some configurations, e.g., lying on the bottom
of a tank, lake, or other body of fluid. Various types of sealants
may be used throughout.
[0043] In addition, the present invention may find use in many
different applications, such as irrigation, dewatering mines, power
generation, water wells, oil wells, reverse-osmosis systems,
driving crankshafts, and others. The present invention is
particularly well suited for use in oil or water fluid production
wells (i.e., free-flowing fluid environments) as a replacement to
the motor of the lifting mechanism. The present invention may also
be used for driving crankshafts or other mechanical devices to
obtain rotary or linear movement.
* * * * *