U.S. patent number 3,641,881 [Application Number 05/009,268] was granted by the patent office on 1972-02-15 for drive mechanism.
This patent grant is currently assigned to E-C Corporation. Invention is credited to Hadi T. Hashemi.
United States Patent |
3,641,881 |
Hashemi |
February 15, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
DRIVE MECHANISM
Abstract
A drive mechanism for using a high-pressure fluid to directly
impart rotation to a rotatably mounted body, the mechanism
including cylinders mounted concentrically around the axis of
rotation of the body and each containing a piston reciprocably
mounted in each cylinder for reciprocating movement in a direction
which is radial relative to the rotational axis of the body. A
piston rod or equivalent structure extends radially outwardly from
the piston and bears against a continuous surface which
eccentrically surrounds the rotational axis of the body. Fluid
passageways extend through the body and communicate with each
cylinder. A stationary structure is provided adjacent the openings
of the fluid passageways into the body, and is ported to
alternately admit fluid at relatively high pressure, and then fluid
at relatively lower pressure to each of the fluid passageways in
the body as the body is rotated about its axis. The sequence and
timing of those pressure variations in each fluid passageway, and
thus in each radial cylinder communicating therewith, is such that
relatively high-pressure fluid acts against each piston when its
piston rod, in contacting the continuous eccentric surface,
develops a reaction force which causes the body to rotate in one
direction, and relatively low-pressure fluid acts against each
piston when its piston rod, in contacting the continuous eccentric
surface, develops a reaction force which opposes rotation of the
body in said one direction.
Inventors: |
Hashemi; Hadi T. (Norman,
OK) |
Assignee: |
E-C Corporation (Dallas,
TX)
|
Family
ID: |
21736614 |
Appl.
No.: |
05/009,268 |
Filed: |
February 6, 1970 |
Current U.S.
Class: |
91/483; 91/492;
417/225 |
Current CPC
Class: |
F04B
9/1176 (20130101); F01B 13/062 (20130101); B01D
61/06 (20130101); F03C 1/2407 (20130101); F01B
3/0035 (20130101); F01B 3/0055 (20130101) |
Current International
Class: |
C02F
1/00 (20060101); B01D 61/02 (20060101); B01D
61/06 (20060101); F01B 13/00 (20060101); F01B
13/06 (20060101); F01B 3/00 (20060101); F04B
9/00 (20060101); F04B 9/117 (20060101); F03C
1/24 (20060101); F03C 1/00 (20060101); F01b
013/06 () |
Field of
Search: |
;417/225
;91/492,485 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Freeh; William L.
Claims
What is claimed is:
1. A drive mechanism comprising:
a cylindrical rotor having planar end faces and a rotational axis
extending centrally through said rotor between said end faces, said
rotor having fluid conveying axial bores extending therethrough
between the end faces and radially offset from the axis
rotation;
a movable piston element reciprocably mounted in each bore;
stationary structures positioned opposite each end face of the
rotor, and each having at least two spaced fluid ports therein
positioned for sequential periodic registry with each of the bores
through the rotor during the rotation of the rotor for alternately
introducing to each of said axial bores from the spaced fluid ports
in each of said stationary structures, first a relatively
high-pressure fluid and then a relatively low-pressure fluid, the
fluid ports in one of said stationary structures being aligned with
the fluid ports in the other of said stationary structure so that
two fluid ports at opposite ends of the rotor communicate
concurrently with each other through one of said axial bores each
time one of said axial bores registers with any one of the fluid
ports, whereby said relatively high-pressure fluid may be
introduced to each of said axial bores on one side of said movable
piston therein concurrently with the expulsion of relatively
low-pressure fluid from the same respective axial bore at a
location on the opposite side of said movable piston with said
introduction and expulsion taking place through two of said ports
concurrently aligned with said respective axial bore;
cylinders connected to said rotor for rotation therewith, and
including a pair of cylinders communicating with each of said bores
at locations on opposite sides of the movable piston element
reciprocably mounted in the respective bore, said cylinders thus
being positioned for receiving fluid under pressure from the
portions of each bore on opposite sides of the respective movable
piston element therein, all of said cylinders being disposed
radially outwardly relative to the axis of rotation of said
rotor;
piston means reciprocably mounted in each of said cylinders for
reciprocating movement in a direction extending radially from the
axis of rotation of said rotor; and
a continuous surface around said axis of rotation externally of
said cylindrical rotor, and having a portion which is eccentric
with respect to said axis of rotation, said continuous surface
being positioned radially outwardly from said cylinders and piston
means, said piston means contacting said continuous surface
continuously during rotation of said rotor and said cylinders
connected thereto for rotation therewith.
2. A drive mechanism as defined in claim 1 wherein the ports in
said stationary structures are arranged relatively to the
eccentricity of said continuous surface, and the location of said
cylinders and piston means located therein is, such that
high-pressure fluid may be introduced through at least one of said
ports to each of said axial bores at a time when the piston means
in the respective cylinder communicating with the respective bore
sustains a reaction force in contacting said eccentric surface
which causes the rotor to rotate in one direction, and such that
relatively lower-pressure fluid may be introduced through at least
one of said ports in the stationary structure at the opposite end
of said rotor to each of said axial bores at a time when the piston
means in the respective cylinder at that time communicating with
that respective axial bore sustains a reaction force in contacting
said eccentric portion of said continuous surface which opposes
rotation of the rotor in said one direction, whereby the net torque
imparted to said cylindrical rotor via said cylinders connected
thereto as a result of the reaction forces described is a torque
driving said rotor in rotation in said one direction.
3. A drive mechanism as defined in claim 1 wherein said continuous
surface has a semicylindrical portion which is concentrically
disposed relative to the axis of rotation of said rotor mounted
body.
4. A drive mechanism as defined in claim 1 wherein said continuous
surface is rotatable about the axis of rotation of said cylindrical
rotor whereby the distance separating any one of said cylinders at
a particular time during the rotation of said continuous surface,
from a point in said cylindrical surface, can be selectively varied
to vary the torque developed by said drive mechanism.
5. A drive mechanism as defined in claim 1 wherein said continuous
surface includes a pair of interconnected semicylindrical portions,
one of said semicylindrical portions being concentric to said axis
of rotation of the cylindrical rotor, and the other semicylindrical
portion being eccentric with respect to said axis of rotation of
the cylindrical rotor.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to drive mechanisms in which fluid pressure
is used to drive rotatably mounted bodies in rotation, and more
particularly, but without being limited thereto, to a hydraulic
drive system in which a pressurized liquid passing through an
energy exchange engine is utilized to supply the power for driving
the exchange engine.
2. Brief Description of the Prior Art
In U.S. Pat. No. 3,431,747, there is illustrated and described an
engine for exchanging energy between high- and low-pressure
systems. This engine includes a cylindrical rotor having axial
bores therethrough which, as the rotor is rotated, are periodically
communicated with the ports formed in seal plates disposed at
opposite ends of the rotor. A freely displaceable movable piston
element is located in each rotor bore, and through the ported seal
plates, high-pressure and low-pressure fluids are alternately
introduced to the bores as the rotor is rotated so that the
pressure energy of the high-pressure fluid is efficiently
transferred to the low-pressure fluid. The utilization of this
device in the production of fresh water from saline aqueous
solutions by exchange crystallization is described.
Since the energy requirement to recover fresh water from saline
aqueous solutions is of paramount importance to the economic
feasibility of any such process, the power required to drive the
rotor of the described energy exchange engine is a critical
consideration. As it is proposed to power the rotor forming a
portion of the energy exchange engine described in U.S. Pat. No.
3,431,747, a motor is drivingly connected to a shaft which projects
from the rotor, and in actual practice, the rotor of this type of
exchange engine has heretofore been typically driven by a
2-horsepower electric motor in order to produce uniform and stable
rotation of the engine under varying tests and pilot plant
conditions. Less than one-quarter horsepower is actually needed,
however, to offset the friction loss generated by the seals and
bearings which hold the rotor in place and which permit the high-
and low-pressure fluids to be charged to the axial bores in the
rotor. The rest of the consumed power is lost in the necessary gear
reduction mechanism by which power is transferred from the motor to
the rotor shaft.
In energy exchange engines of the type described, several
disadvantages characterize the use of an electric motor as the
prime mover for the rotor. When this type of power source is
employed, the energy exchange engine is not self-sufficient-- that
is, it is dependent upon an external source of power in order to
operate in the manner required. There is, moreover, as indicated, a
considerable power loss which results from the necessary employment
of a gear reduction mechanism. Also, since the load generated by
the energy exchange engine is variable during its operation, an
electric motor utilized for driving the rotor must necessarily have
a substantially higher power rating than that which is required for
normal operation of the engine during the average load requirement.
Finally, the electric motor and gear reduction mechanism constitute
a substantial part of the capital and operating cost of the
engine.
BRIEF DESCRIPTION OF THE PRESENT INVENTION
The present invention constitutes a drive mechanism employing a
pressurized fluid as the ultimate energy source, and which can be
utilized for driving rotatably mounted bodies in rotation. The
drive mechanism is peculiarly well adapted for use in conjunction
with an energy exchange engine of the type described. In this
application, the pressurized fluids utilized for powering the drive
mechanism are the liquids or slurries between which pressure is
transferred in the engine.
Broadly described, and without respect to any specific application,
the drive mechanism of the present invention comprises a body
mounted for rotation about an axis extending therethrough and
having fluid passageways extending into the body from an exposed
surface thereof, with the openings to said fluid passageways spaced
radially outwardly from the axis of rotation of the body. At least
one, and preferably a plurality of cylinders are connected to the
body for rotation therewith, and are disposed radially outwardly
relative to the axis of rotation of the body. Such cylinders may be
merely cavities or bores formed in the body, or may be formed
separately and secured in any suitable manner to the body for
rotation concurrently therewith.
Each cylinder contains piston means which is reciprocably mounted
in the cylinder for movement radially with respect to the axis of
rotation of the body, and the passageways in the body each
communicate with one of the cylinders radially inwardly of the
piston means which is located therein. At least one continuous
surface is provided radially outwardly from the axis of rotation of
the body and on the opposite side of the cylinders from this axis,
and over at least a portion of its total extent, each of said
continuous surfaces is eccentrically shaped relative to the axis of
rotation of the body. The piston means in the several cylinders
each contact one of the continuous surfaces, and move across the
eccentric portion thereof during rotation of the body. A ported
structure is disposed adjacent the body and has a plurality of
ports formed therethrough in a position to register in sequence
with the fluid passageways in the body during rotation of the body,
and thus to alternately deliver relatively high-pressure fluid to
each passageway, and then lower-pressure fluid thereto. The
arrangement of these ports in relation to the cylinders and the
continuous surfaces is such that the relatively high-pressure fluid
acts against each piston means at a time when it contacts an
eccentric portion of one of said continuous surfaces at a location
such that a reaction force is developed which drives the body in
rotation in one direction, and the relatively low-pressure fluid
acts against the piston means either at a time when no torque is
developed by reaction forces, or when a reaction force is developed
which opposes rotation of the body in said one direction.
In a preferred embodiment of the invention, the rotatably mounted
body is the cylindrical rotor of an energy exchange engine, and the
ported structure utilized includes a pair of seal plates located at
each end of the rotor, and having high- and low-pressure ports
therethrough which alternately register with axial bores extending
over the length of the rotor and substantially parallel to its
rotational axis. The cylinders which carry the described piston
means are preferably formed in hydraulic drive units which are
interposed between each of the seal plates and the respective
adjacent ends of the cylindrical rotor. In this position, the inner
end of each of the piston means is exposed to the pressure of fluid
in the axially extending bores of the rotor, and the other end
projects radially outwardly into contact with the continuous
surface carrying the described eccentricity. The rotor is caused to
turn as a result of the torque generated by the pressure exerted on
the eccentric portion of the continuous surfaces by the piston
means at a time when those bores of the rotor which communicate
with the cylinders carrying these piston means are in communication
with one or more high-pressure ports through the seal plate.
From the foregoing broad description of the invention, it will be
perceived that an important object of the invention is to provide a
drive mechanism by which fluid pressure can be utilized for the
generation of torque in order to drive a rotatable body in
rotation.
An additional object of the invention is to provide a relatively
mechanically simple, inexpensively constructed drive mechanism,
using a pressurized fluid as an energy source, and having
relatively few moving parts.
A further and more specific object of the invention is to provide
an energy exchange engine for transferring pressure energy from a
relatively high-pressure fluid to a relatively low-pressure fluid,
which energy exchange engine is self-sufficient in providing its
own power for the purpose of rotating a rotor forming a portion
thereof.
Another object of the invention is to provide an energy exchange
engine which has no exposed moving parts and which requires no gear
reduction device in order to operate the engine.
An additional object of the invention is to provide an energy
exchange engine which includes a rotatably mounted rotor which can
be driven by the application of an easily and selectively variable
torque, at a selectively varied speed and in a manner which permits
a selected power output to be obtained.
Yet another object of the invention is to provide an energy
exchange engine of high efficiency in which the work of expansion
of the high-pressure liquid in the bores of a rotor forming a
portion of the engine is sufficient to generate the required torque
so that the power used to drive the rotor of the engine in rotation
can come from recovering at least a portion of the losses which
otherwise would occur due to sudden depressurization of the
high-pressure liquid which is charged to the engine.
In addition to the foregoing described objects and advantages,
additional objects and advantages of the invention will become
apparent as the following detailed description of preferred
embodiments of the invention is read in conjunction with the
accompanying drawings which illustrate the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view, partially in section and partially in elevation,
of an engine for exchanging energy between high- and low-pressure
systems, which engine incorporates the drive mechanism of the
present invention.
FIG. 2 is a sectional view taken along line 2--2 of FIG. 1.
FIG. 3 is a diagrammatic illustration of the manner in which torque
is developed by the drive mechanism of the present invention,
showing the relation of the drive mechanism to certain parts of an
energy exchange engine of the type depicted in FIG. 1 with which
the drive mechanism may be used.
FIG. 3A is a vector diagram illustrating the direction of applied
and reaction forces developed in drive mechanism illustrated in
FIG. 3.
FIG. 4 is a diagram illustrating the manner in which certain parts
of the drive mechanism of the invention can be varied in their
relation to each other in order to selectively control the torque
developed by the drive mechanism.
FIG. 5 is a view similar to the sectional view of FIG. 2, by
illustrating a portion of a modified embodiment of the
invention.
FIG. 6 is a diagrammatic illustration of the manner in which yet
another embodiment of the invention is constructed.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
In order to more clearly explain the operation principles of the
drive mechanism of the present invention, as well as to facilitate
description of a preferred application of this drive mechanism in
combination with certain additional structure constituting an
energy exchange engine for exchanging energy between high- and
low-pressure systems, reference will initially be made to FIG. 1
which shows an energy exchange engine of this type having the drive
mechanism of the present invention incorporated therein. The engine
includes a solid cylindrical rotor 10 which has a pair of spaced
end faces 12 and 14. Extending through the rotor 10 in an axial
direction are a plurality of circumferentially spaced,
substantially parallel fluid passageways or bores of generally
circular cross section. Two of these axially extending bores are
perceptible in FIG. 1, and are designated by reference numerals 16
and 18. It will be noted that the bores 16 and 18 each open at
their opposite ends in the end faces 12 and 14 of the rotor 10, and
this is characteristic of all of the axially extending bores, of
which there are a total number of eight spaced circumferentially
from each other around the rotor.
Pressed into the two end portions of each of the bores are ball
stops. The ball stops at the opposite ends of the elongated,
axially extending bore 16 are designated by reference numerals 20
and 22, and those at the opposite ends of the elongated axially
extending bore 18 are designated by reference numerals 24 and 26. A
small spherical member or ball 28 is rollably mounted in each axial
bore and effectively forms a free piston reciprocably located in
the bore and dividing the bore into two chambers.
Surrounding the cylindrical rotor 10 is a housing 32. The housing
32 has an internal cylindrical wall 32a which is positioned in
contact with the cylindrical outer peripheral wall of an eccentric
sleeve 34. The eccentricity of the sleeve 34 refers to the
configuration and location of its inner peripheral surface 34a with
respect to the rotational axis of the rotor 10 which extends
through the rotor and coaxially along a pair of stub shafts 33 and
35 extending from the opposite end faces 12 and 14 of the rotor. It
will be noted in referring to FIG. 1 that the housing 32 is of
greater axial length than the rotor 10 so that it projects beyond
the end faces 12 and 14 of the rotor.
A pair of end or closure plates 39 and 36 are secured to the
housing 32 by axially extending bolts 37. The closure plate 39 is
provided with a centrally located bore 38 into which the stub shaft
33 extends. A suitable O-ring seal 40 is provided in an
accommodating groove in the bore 38 and seals around the stub shaft
33. An annular bearing 42 is seated in a counterbore 44 formed in
the closure plate 34 and journals the stub shaft 33. In like
manner, the closure plate 36 has a bore 46 disposed centrally
therein, and has a groove 48 formed in this bore to accommodate a
seal 50 which seals around the stub shaft 35. A counterbore 52 is
formed in the closure plate 36 and receives an annular bearing 54
which rotatably journals the stub shaft 35.
In an annular recess 56 formed in the closure plate 39 around the
bore 38 is located a ported seal plate designated generally by
reference numeral 58. The seal plate 58 sealingly contacts a wear
plate 60 which is seated in a counterbore 62 formed in the closure
plate 39. In an annular recess 64 formed around the bore 46 through
the closure plate 36, a ported seal plate designated generally by
reference numeral 66 is located, and sealingly engages a wear plate
68 which is positioned in a counterbore 70 formed in the closure
plate 36. The wear plates 60 and 68 are secured to, and sealingly
engage, a pair of hydraulic drive units designated generally by
reference numerals 72 and 74 and hereinafter described in greater
detail. The hydraulic drive units 72 and 74 constitute drive
mechanisms constructed in accordance with the present invention and
are each secured by bolts or other suitable securing devices to the
end faces 12 and 14, respectively, of the rotor 10. Thus, the
hydraulic drive units 72 and 74 and the wear plates 60 and 68
rotate with the rotor 10.
It should be here pointed out that the wear plates 60 and 68 and
the seal plates 58 and 66 form no part of the present invention
except as they are used in combination with the drive mechanisms of
the invention, and these elements of the energy exchange engine
depicted in FIG. 1 are described in detail in copending U.S.
application Ser. No. 773,837 assigned to the assignee of the
present application. Before proceeding to a detailed description of
the hydraulic drive units 72 and 74 which are constructed in
accordance with the present invention, however, it will be helpful
to the subsequent description to point out that the closure plate
36 has extending therethrough, a pair of fluid passageways or
ports, these being a low-pressure fluid inlet passageway or port 80
formed through the closure plate and a high-pressure fluid
discharge passageway or port 82 also formed through the closure
plate 39 on the opposite side thereof from the low-pressure fluid
discharge port 80. In similar fashion, an elongated, high- pressure
fluid inlet port or passageway 84 extends through the closure plate
39 in a direction substantially parallel to the bore 38 through
this closure plate, and a low-pressure fluid discharge passageway
or port 86 is formed on the opposite side of the closure plate 39
and extends parallel to the high-pressure inlet port 84. Suitable
conduits 88 and 90 deliver low-pressure fluid to the port 80, and
receive high-pressure fluid from the port 82, respectively.
Similarly, suitable conduits 92 and 94 deliver high-pressure fluid
to the port 84 and receive low-pressure fluid from the port 86,
respectively.
The high-pressure inlet passageway or port 84 in the closure plate
39 communicates with a high-pressure port 95 through the seal plate
56, which high-pressure port is bounded by an arcuate seal plate
retainer flange 96. Similarly, the low-pressure discharge
passageway or port 86 communicates with a low-pressure port 97
through the seal plate 56, which port is bounded by an arcuate seal
plate retainer flange 98. The seal plate retainer flanges 96 and 98
aid in retaining the seal plate 58 in the illustrated position and
bound the high- and low-pressure ports 95 and 97 through the seal
plate. The ports 95 and 97 are of arcuate configuration as
illustrated by the dashed lines illustrating similar ports in FIG.
3. The high-pressure discharge passageway or port 82 communicates
with the interior of an arcuate seal plate retainer flange 100
shaped substantially identically to the shape of the arcuate seal
plate retainer flange 96, and bounding a high-pressure port 101 in
the seal plate 66. The low-pressure discharge passageway or port 80
communicates with the zone inside an arcuate seal plate retainer
flange 102 which is also shaped like the retainer flanges 96, 98
and 100, and which bounds the arcuate low-pressure port 103 in the
seal plate 66. Positioned in alignment with the several axial bores
which extend through the rotor 10 are openings formed through the
wear plate 60, the two which are visible in FIG. 1 being designated
104 and 106. Similarly, circumferentially spaced openings are
formed through the wear plate 68 and are aligned with the bores
through the rotor 10.
The construction of the hydraulic drive units 72 and 74 may be best
understood by referring to FIG. 2 in conjunction with FIG. 1. It
will here be noted that each of the identically constructed
hydraulic drive units 72 and 74 includes a disk block 112 which is
secured to the respective end face 12 or 14 of the rotor 10 by
means of screws or bolts 114, and which is keyed to the respective
stub shaft 33 or 35 by means of a suitable key 116 which is fitted
in mating grooves in the respective stub shaft and the disk block
112. Each of the disk blocks 112 of the two hydraulic drive units
72 and 74 is thus secured flatly against the adjacent end face of
the rotor 10 and rotates with the rotor. Suitable O-ring seals 118
are provided between the face of the disk block 112 of the
hydraulic drive unit 72 and the end face 12 of the rotor 10 around
each of the elongated, axially extending bores which extend through
the rotor, so that no fluid is permitted to leak between the disk
block and the end face of the rotor. In similar fashion, O-ring
seals 119 are provided around the openings to each of the
elongated, axially extending bores in the rotor at the end face 14
thereof for establishing a seal between this end face and the disk
block 112 of the adjacent hydraulic drive unit 74. Seals 120 and
121 are also provided between the wear plates 60 and 68 and the
hydraulic drive units 72 and 74.
Each of the disk blocks 112 of the two hydraulic drive units 72 and
74 has a plurality of circumferentially spaced openings or ports
122 formed therethrough in a position spaced radially outwardly
from the axis of rotation of the rotor 10, and positioned for
registry with the several elongated, axially extending bores which
are formed through the rotor. Thus, fluid flowing to and from the
axial bores in the rotor 10 enters the respective aligned port 122
formed in the adjacent disk block 112 of the respective hydraulic
drive unit 72 or 74. Each of the disk blocks 112 of the two
hydraulic drive units is provided with radially extending
cylindrical bores 124 which each intersect one of the ports 122
extending through the disk block. There are further provided in
each disk block 112, a series of counterbores 126, with each of
these counterbores communicating with one of the bores 124.
Reciprocably positioned in each of the cylindrical bores 124 is a
piston 128 which has its outer periphery sealingly engaged by
suitable sealing elements 130 to prevent fluid bypass of the
piston. The radially outer end of each piston 128 bears against a
roller block 132 which is reciprocably mounted in the counterbore
126. In the illustrated embodiment of the invention, both the
roller block 132 and the counterbore 126 are of substantially
rectangular cross-sectional configuration. Rollably journaled in
each roller block 132 is a roller 134. Each of the rollers 134 is,
as shown in FIG. 2, in contact with the inner peripheral surface of
the eccentric sleeve 34. It will be noted in referring to the
cross-sectional configuration of the eccentric sleeve 34 as
illustrated in FIG. 2 that the outer peripheral surface of this
sleeve which engages the internal surface 32a of the housing 32 is
formed concentrically with respect to the rotational axis of the
rotor 10 as extended through the stub shaft 35. The internal
peripheral surface of the eccentric sleeve 34, however, is formed
eccentrically with respect to this axis so that that portion of the
sleeve which is located near the left side of FIG. 2 is of lesser
thickness than the portion of the sleeve located toward the right
side of FIG. 2. Stated differently, the center of curvature of the
eccentric inner surface 34a of the eccentric sleeve 34 is displaced
laterally from the center of curvature of its external surface, and
from the center of curvature of the inner and outer cylindrical
surfaces of the housing 32.
The operating principles of the drive mechanism of the invention
can best be explained by reference to FIG. 3 of the drawings. Here
a disk block forming a part of a drive mechanism similar to the
hydraulic drive units 72 and 74 illustrated in FIG. 1 is
schematically depicted, and is designated by reference numeral 140.
The disk block 140, it will be understood, is secured to and
movable with a rotating body (not shown), such as the rotor 10 of
the energy exchange engine depicted in FIG. 1. The disk block 140
has one or more openings or ports 142 each formed therethrough in
alignment with a bore or fluid passageway formed through the
rotating member and alternately receiving relatively high-pressure
fluid and relatively low-pressure fluid as the rotating member is
rotated. Such bores thus correspond to the axially extending bores
(such as 16 and 18) formed in the rotor 10 of the energy exchange
engine shown in FIG. 1, with these latter bores acting at various
times to convey relatively high- and relatively low-pressure fluids
in a manner hereinafter explained.
The opening 142 in the disk block 140 communicates with a radially
extending cylinder 144 which is formed in the disk block, and which
slidingly and reciprocably receives a piston 146. The piston 146
has projecting radially outwardly therefrom, a piston rod 148 which
bears at its outer end against a cylindrical surface 150 which is
disposed eccentrically with respect to the axis of rotation of the
rotating body and of the attached disk block 140. This axis of
rotation extends through point O which is the center of curvature
of the outer peripheral surface of the disk block 140. The center
of curvature of the cylindrical surface 150, on the other hand, is
designated by reference numeral O' and is seen to be displaced or
offset from the point O. The cylindrical surface 150 constitutes
the inner peripheral surface of an eccentric member 152, such as
the eccentric sleeve 34 utilized in the energy exchange engine
depicted in FIG. 1. The eccentric member 152 is shown as confined
within a cylindrical housing 154 which may be likened to the
housing 32 depicted in FIG. 1.
Shown in dashed lines in FIG. 3 are the outlines of a pair of
arcuate openings, these being referred to as a high-pressure
opening or port 156 and as a low-pressure opening or port 158.
These ports are like those formed through the seal plates 58 and 66
and bounded by the arcuate seal plate retaining flanges formed on
the closure plates 39 and 36 in FIG. 1, and function to supply a
fluid at relatively high pressure (in the case of the port 156) and
a fluid at relatively lower pressure (in the case of the opening
158) in alternating sequence to the bores provided through the
rotatably mounted body secured to the disk block 140, such fluids
being conveyed to and from these bores through openings which are
provided in the disk block 140. Thus, it will be noted that the
opening 142 is positioned in the disk block 140 for registry in
alternating sequence with the high-pressure port 156 and the
low-pressure port 158 as the rotor and the disk block 140 carried
thereby are rotated about the rotational axis which extends through
point O. It will be understood, of course, that for purposes of
explaining the operating principles of the present invention, the
schematic drawing of FIG. 3 illustrates only a single opening 142,
a single-cylinder bore 144, and a single-piston element 146, even
though a plurality of these elements would be provided in the disk
block 140 in operating embodiments of the invention, similar to the
number of equivalently functioning elements provided in the
embodiment depicted in FIG. 2 of the drawings.
When a bore through the rotor is communicated through one of the
openings 142 in the disk block 140 with the high pressure port 156
formed through, for example, a seal plate which is adjacent the
disk block 140, the high pressure of the fluid will force the
piston 146 outwardly in the cylinder 144 so that the piston rod 148
bears continuously against the cylindrical surface 150. This
surface is, of course, eccentric with respect to the axis of
rotation of the disk block 140 and any rotatably mounted body
attached thereto. The magnitude of the force which is applied
through the piston rod 148 to the surface 150 is equal to p.sub. 2
.sup.. A where A is the piston area, and p.sub. 2 is the pressure
of the relatively high-pressure fluid at the high-pressure port
156. This pressure, of course, acts in the opening 142 and in the
cylinder 144 radially inwardly of the piston 146. Opposing the
applied force directed against the surface 150 by the piston rod
148 is a reaction force developed by the eccentric surface. This
reaction force acts radially inwardly with respect to the center of
curvature O' of the eccentric surface. The direction of the
outwardly acting force applied to the eccentric cylindrical surface
150 through the piston rod 148 is thus angled with respect to the
direction in which the reaction force acts, the angle separating
the directions of action of the two forces being designated as
.theta.'.
The reaction force which acts along a radius, R, of the eccentric
surface 150 can be broken into two force components. One of these
extends exactly opposite the force applied through the piston rod
148 to the eccentric surface 150, and the other acts perpendicular
to the direction of this applied force. The force component acting
perpendicular to the applied force generates a torque which causes
rotation of the disk block and the rotatably mounted body attached
thereto. Thus, the torque, T, generated by the radially moving
piston 146 and piston rod 148 in an angular position .theta.
(measured with respect to a line projected through the points O and
O') is given by,
T= p.sup. . A.sup. . l tan .theta.' (in.-lb.) (1)
where
p = bore pressure and pressure in cylinder 144 (p.s.i.)
A = area of piston face exposed to fluid pressure (square
inches)
l =distance between center of rotation, O, and the point of contact
between the piston and the eccentric circle (inches)
.theta.' = the angle between the applied force and the reaction
force (radians)
For the purposes of explanation, it may be considered that the
fluid at relatively high pressure P.sub. 2 from port 156 acts on
the piston 146 for the condition O .theta. .pi., and that the fluid
at relatively low pressure P.sub. 1 from port 158 acts on the
piston 146 for the condition .pi. .theta. 2.pi.. When .theta.=0,
.theta.' is also zero, and there is at this time no net torque. As
.theta. increases, the resultant torque also increases to a
maximum, and then declines to zero again when
.theta.=.pi.(180.degree.). For .pi. .theta. 2.pi., the piston 146
is pushed inwardly against the pressure acting in the opening 142
and within the cylinder 144 at this time.
If the eccentricity of the surface 150 is properly related to the
geometric orientation of the high-pressure and low-pressure ports
156 and 158, respectively (as it is in FIG. 3), the relatively
low-pressure fluid (at pressure P.sub. 1) can be made to act upon
the piston 146 at this time. In this region, there is a negative
resultant torque (since the perpendicular component of the reaction
force acts now in the opposite direction from the direction of
rotation), and this negative torque, of course, resists rotation of
the rotor. This negative torque is zero at .theta.=.pi. and
.theta.=2.pi., and it reaches a maximum absolute value as .theta.
is increased from .pi. toward 2.pi.. The value of the resultant
torque at any time is, however, a function of the pressure p acting
on the piston 146 as shown by Equation (1). Therefore, the negative
torque which is applied to the disk block 140 during the time that
the angle .theta. is between .pi. and 2.pi. is smaller than that of
the positive torque generated as .theta. is being increased from
zero to .pi. at a time when the opening 142 in the disk block 140
is aligned with the high-pressure port 156. In other words, since
the pistons 146 are pushed inwardly against relatively low pressure
fluid during the time when the eccentricity of the surface 150
results in the generation of a negative torque, the absolute value
at the resultant negative torque for a value of .theta. between
.pi.O O'2.pi. is smaller than that of the resultant positive torque
generated in the region where .theta. has a value of between 0 and
.pi. by a factor of P.sub. 2 /P.sub. 1.
Referring back to Equation (1), and to FIG. 3A, it will be noted
that l and .theta.' are both functions of the angular position,
.theta., the eccentricity, e, (i.e., the distance 0 0') and the
radius, R, of the eccentric surface 150. Thus, the following
expressions may be obtained:
where
e = distance 00' (eccentricity), in inches
p(.theta.) = the pressure acting on the pistons at an angular
position .theta., in p.s.i.
T(.theta.) = the torque developed when pistons are at the angular
position .theta., in inch-lbs
Assuming that the speed of rotation is s revolution per minute
(r.p.m.) and that
p(.theta.) = p.sub. 2 for 0 .theta. .pi.
= p.sub. 1 for .pi.<.theta.<2.pi. ##SPC1##
The average torque, T, is then,
T = P/2.pi.s= e.sup. . A.sup. . (p.sub. 2 -p.sub. 1)/.pi. inch-lbs
(6)
As an example, let e=1/4 inch, and let A=.pi./16 in..sup.2, and let
p.sub. 2 in.-lb. p.sub. 1 =2500 p.s.i. Then
T= 1/4.sup.. .pi./16.sup. . 2500.sup. . 1/.pi.=2500/64= 39.1 in-lb.
and
For s=60 r.p.m., the average power output per piston becomes 0.0372
hp. per piston.
If a piston is located at each end of each rotor bore, and there
are eight bores, the total net torque is 625 in.-lb., and the total
power output becomes 0.645 hp.
OPERATION
The drive mechanism of the present invention will be seen from the
foregoing description to provide a device by which hydraulic or
pneumatic pressure can be utilized for developing torque applied to
a rotatably mounted body. Thus, the hydraulic drive units 72 and 74
illustrated in conjunction with the energy exchange engine in FIG.
1 are utilized to drive the rotor 10 in rotation, and function to
replace a motor which would otherwise necessarily be connected for
driving purposes to an extension of one of the stub shafts 33 or
35. Such motor driven operation is described in U.S. Pat. No.
3,431,747.
When the hydraulic drive units 72 and 74 are employed for driving
the rotor 10 of the energy exchange engine in rotation, the manner
in which the structure depicted in FIGS. 1 and 2 functions is as
follows. Let it be assumed at the outset that two process liquids
which shall be called liquid A and liquid B are available in an
industrial process at pressures P.sub. 2 and P.sub. 1,
respectively. Let it be assumed that the pressure P.sub. 1 of
liquid B is substantially greater than the pressure P.sub. 2 of
liquid A. It is not material what two liquids are employed and, in
fact, both of the liquids may be a slurry. Gases may also be
employed, although the preferred and most advantageous use of the
pressure exchange engine occurs when liquids or pumpable slurries
are utilized.
With a source of liquid A at pressure P.sub. 2 available, this
source is connected to the low-pressure fluid inlet passageway 80
through the conduit 88 so that liquid A at pressure P.sub. 2 may
enter this passageway, and from this passageway be passed through
the low-pressure arcuate port through the seal plate 66 and defined
by the arcuate seal plate retainer flange 102. From the
low-pressure arcuate port in the seal plate 64, the liquid A at
pressure P.sub. 2 passes through openings such as the opening 110
in the wear plate 68 and enters one or more of the openings 122
formed through the disk block 112 of the hydraulic drive unit 74,
as such openings through the disk block may at that time be in
registry with the low pressure arcuate port in the seal plate 66
through the aligned or registering openings 122 in the wear plate
68. Thus, the liquid A at the relatively low pressure P.sub. 2
comes to act upon the inner face of the pistons 128 which project
into the openings or ports 122 then aligned to receive such
relatively low-pressure liquid. The low-pressure liquid also passes
into the axial bores, such as bore 18, through the rotor 10 which
are aligned with the ports 122 through the disk block 122, which in
turn are aligned with the low-pressure arcuate port through the
seal plate 66. Relatively low-pressure fluid is concurrently acting
outwardly on the pistons 128 so as to force the rollers 134
outwardly against the inner peripheral surface of the eccentric
sleeve 34. From the previous discussion herein, it will be
understood that the portion of the inner surface 34a of the
eccentric sleeve 34 against which the rollers 134 at this time bear
is that portion over which the distance separating this surface
from the external peripheral surface of the rotor 10 is decreasing
(or, stated differently, the portion of the inner peripheral
surface 34a of the eccentric sleeve 34 over which the angle .theta.
is increasing from .pi. to 2.pi. as previously described). Thus,
the inward motion of pistons 128 against the force of the low
pressure fluid generates negative torque. The passageway 86 through
the closure plate 39 is connected to a relatively low-pressure
zone, in most instances, at atmospheric pressure. Thus, the balls
28 will be reciprocated in the axial bore 18 and similarly located
rotor bores toward the left as viewed in FIG. 1 under the impress
of the relatively low-pressure fluid entering this bore from the
passageway 80 in the closure plate 36 via the seal plate 66, the
wear plate 68 and certain of the ports 122 formed in the disk block
112 of the hydraulic drive unit 74.
The high-pressure inlet passageway 84 in the closure plate 39
receives the liquid B from the conduit 92, this liquid being at the
relatively high pressure P.sub. 1. Finally, the high-pressure
discharge passageway 82 is connected to suitable liquid confining
means which can retain a liquid under pressure, and can permit the
liquid under pressure to be pumped thereinto from the high-pressure
fluid discharge passageway 82 via the conduit 90.
After the relatively high-pressure liquid B passes from the
passageway 84 through the arcuate high-pressure port provided in
the seal plate 58, and through the series of registering ports 104
provided through the wear plate 60, this high-pressure liquid then
enters the particular group of the ports 122 through the disk block
112 of the hydraulic drive unit 72 which are also in alignment or
in registry with the arcuate high-pressure port in the seal plate
58. The group of radial cylinders 124 formed in the disk block 112
of the unit 72 which communicate with the ports 122 receiving
high-pressure liquid B at this time are thus also filled with this
high-pressure liquid, and the pistons 128 reciprocably mounted in
these respective cylinders are forced radially outwardly by the
high-pressure liquid. The rollers 134 are thus caused to develop a
force acting on the eccentric cylindrical surface 34a of the
eccentric sleeve 34, and by proper arrangement of the sleeve, as
hereinbefore described, a net positive torque is developed tending
to cause the rotor 10 to undergo rotation. This net positive torque
is, of course, of greater magnitude than the negative torque
developed as a result of the action of pistons 128 against the
relatively low pressure liquid A on certain others of the pistons
128 due to the higher magnitude P.sub. 1 of the pressure at which
the liquid B is introduced to the hydraulic drive unit from the
passageway 84.
After passing through the ports 122 in the disk block 112 of the
hydraulic drive unit 72, the high-pressure liquid B enters the
axial bores in the rotor 10 which at that time communicate through
the ports 122 with the high-pressure arcuate port in the seal plate
58. The ball 28 is thus forced to the right in these bores so as to
displace liquid located in the axial bore to the right of this
ball, and force this liquid into the confining means previously
described so as to build up the pressure of the liquid contained in
such confining means. Due to the confinement of the liquid
discharged from the high-pressure discharge passageway 82 and the
conduit 90 connected thereto, the liquid contained in the axial
bores 16 of the rotor 10 on the right side of the ball 28 is also
at relatively high pressure in comparison to the relatively
low-pressure liquid A which is passing into the axial bores 18, and
also in comparison to the liquid being discharged from these latter
bores. Thus, a relatively high pressure acts redially outwardly
against the inner ends of the pistons 128 which are carried in
cylinders 124 at that time in communication with certain ports 122
which are in registry through the ports 108 in the wear plate 68
with the arcuate high-pressure port through the seal plate 66.
These particular pistons 128 are thus forced radially outwardly
with respect to the rotor 10 by the relatively high-pressure liquid
acting thereon, and due to the arrangement of the eccentric sleeve
34 in relation to the high-pressure arcuate port of the seal plate
66, a relatively high magnitude positive torque is developed by the
contact of the rollers 134, positioned radially outwardly of these
pistons, with the inner peripheral surface of the eccentric
sleeve.
From what has been described relative to the manner in which the
high-pressure liquid B and the low-pressure liquid A pass through
the closure plates 39 and 36, the seal plates 58 and 66, and the
two hydraulic drive units 72 and 74, it will be perceived that at
all times, a net positive torque will be developed which will cause
the rotor 10 to be rotated about its axis. The energy exchange
engine is thus actuated through the utilization therewith of the
drive mechanism of the present invention. The structure thus
provided can be utilized for efficiently transferring substantially
all of the pressure energy from the relatively high-pressure liquid
B to the relatively low-pressure liquid A. Having set the rotor 10
in rotational motion due to the reaction forces developed and
acting through the pistons 128 of the hydraulic drive units 72 and
74, the axial bores, of which the bores 16 and 18 depicted in FIG.
1 are typical, are, in consecutive sequence, brought into axial
alignment through the registering ports in the disk blocks of the
two hydraulic drive units with the arcuate high-pressure and
low-pressure ports formed in the seal plates 58 and 66, and
diagrammatically illustrated in FIG. 3 of the drawings. With the
alignment of the axially extending bores 16 and 18 depicted in FIG.
1, which may be considered as a typical alignment which will occur
with respect to the other axially extending bores formed through
the rotor 10, the relatively low-pressure liquid A at pressure
P.sub.2 enters the bores aligned as is bore 18 to the right of the
ball 28 via the low-pressure fluid inlet passageway 80, and the
ports through the wear plate, and the ports through the hydraulic
drive unit 74. At the same time, some of liquid B which has been
previously entrapped in the part of the bore 18 to the left of the
ball 28 in these same bores is placed in communication with a vent
or low-pressure environment, and can be discharged through the
low-pressure fluid discharge passageway 86 and the conduit 94 as
the balls 28 are displaced to the left in these bores by the
impress of the relatively low-pressure liquid A entering the right
sides of these bores.
In the case of bores located similarly to the axially extending
bore 16 at the instant depicted in FIG. 1, the relatively
high-pressure liquid B at pressure P.sub. 1 which enters the left
side of these bores from the high-pressure fluid inlet passageway
84 drives the balls 28 toward the right. This displaces the
entrapped liquid A which is disposed in the right side of these
bores as a result of its entry into these bores at a previous time
when the bores occupied positions similar to that shown as occupied
by the bore 18 in FIG. 1. This occurred, of course, at a time
earlier in the rotational movement of the rotor 10. Continued
impress of the high-pressure liquid B upon the left side of the
balls 28 eventually drives the balls to the right side of these
bores and completely displaces the relatively low-pressure liquid A
from these bores at a pressure which is here only slightly less
than that of the high-pressure liquid B as a result of the
confinement of the fluid A being discharged via the conduit 90.
It may thus be seen that as the rotor 10 continues to rotate, the
net effect is that, in being depressurized from its elevated
pressure P.sub.1 to atmospheric pressure, the high-pressure liquid
B is made to transfer effectively its energy of pressurization to
the relatively lower-pressure liquid A. The transfer is highly
efficient due to the minimum energy requirement to displace the
balls 28 in their respective bores, and no valving is included in
the system which can become choked or clogged by any entrained
material carried in the liquids between which the energy transfer
is to take place. Thus, relatively thick slurries of high solids
content can be successfully passed through the pressure exchange
engine without damage to it, despite its use over extended periods
of time for transferring pressure energy between such slurries.
A relatively small amount of the pressure energy of the
high-pressure liquid is dissipated in forcing the pistons 128 of
the hydraulic drive units 72 and 74 outwardly so that the rollers
134 contact the inner peripheral surface of the eccentric sleeve 34
and drive the rotor in rotation. Moreover, it will be perceived
that there are no exposed moving parts and no gear reduction
devices required when the drive mechanism of the present invention
is used for driving the energy exchange engine. As will be
subsequently shown, by adjusting the position of the eccentric
sleeve 34, a wide range of torque or power output can be obtained
with the system which is illustrated. No external source of power
is required to provide a driving force for the rotor 10. The work
of expansion of the high-pressure liquid in the bores is sufficient
to generate the required torque for driving the rotor so that the
power used by the hydraulic drive units 72 and 74 can come from the
recovering of losses due to sudden depressurization of the
high-pressure liquid. This will also be explained in greater detail
hereinafter.
TORQUE AND SPEED VARIATION
The arrangement depicted in FIG. 3 in one in which the line 00'
(interconnecting the center of curvature of the cylindrical surface
150, and the center of curvature of the rotor and disk block 140)
exactly divides the zones of high-pressure fluid action and
low-pressure fluid action as such fluid pressures are brought to
bear upon the piston 146 over periods each roughly approximating
one-half the period required for one revolution of the rotor. The
manner in which the average net torque developed by the drive
mechanism, as well as the speed of the rotor, can be selectively
varied will now be discussed, aided by reference to FIG. 4. In this
schematic illustration, the eccentric surface is designated by
reference numeral 160, and the outer peripheral surface of the
rotor and, more importantly, of a disk block attached thereto, is
designated by reference numeral 162. The center of curvature of the
eccentric circle surface 160 is designated again by reference
numeral 0', and the center of rotation of the cylindrical outer
periphery of the rotor and the disk block is designated by
reference character o. The line C--C is the boundary line
demarcating that portion of the rotational cycle of the rotor and
disk block during which relatively high-pressure fluid acts on the
radially reciprocable pistons hereinbefore described, from that
portion of the rotational cycle of the rotor over which relatively
low-pressure fluid acts on these pistons. It will thus be seen
that, in this instance, instead of the axis 00' coinciding with the
boundary line dividing the high-pressure and low-pressure zones
from each other, the 00' axis extends at some angle .theta." with
respect to the boundary C--C between the high- and low-pressure
zones. With this arrangement, the average net torque output per
piston is given by
T= 2 eA (P.sub. 2 -P.sub. 1) cos .theta." (7)
where, as has been indicated, .theta." is the angle of rotation of
the axis 0-0' relative to the boundary line C--C separating the
high-pressure and low-pressure regions.
For a given drive system, the areas A of pistons upon which the
pressurized fluids will act will generally be fixed (constant), and
the pressure differential (P.sub. 2 -P.sub. 1) between the
high-pressure fluid and the low-pressure fluid should be maintained
at such value as may be required by the operating conditions. With
regard to the latter statement, it will be understood that in such
applications as the employment of the present drive mechanism in
the energy exchange engine used in the desalination of sea water as
described in U.S. Pat. No. 3,431,747, certain pressure
differentials between the high-pressure and low-pressure fluid will
generally prevail so that it may be assumed that for a given
system, the pressure differential P.sub.2 -P.sub.1 will be a
relatively constant condition, or at least will be a parameter not
susceptible to control for purposes of varying the torque and speed
of the rotated body as hereinafter described.
With the piston areas fixed, as well as the pressure differential,
the average net torque output will, as indicated by Equation (7),
be variable by either adjusting the angle .theta." by rotating the
axis 0-0' (that is, by shifting an eccentric sleeve or other
eccentric surface in relation to the rotated body), or by shifting
the position of the eccentric cylindrical surface 160 so as to vary
the distance, e, which separates the points 0.xi.and o'. It will be
apparent, for example, that the distance, e, can be reduced to zero
so as to result in no net torque--that is, the eccentricity of the
surface 160 then no longer exists. Similarly, if .theta." is
increased to .pi./2, the net torque will become zero. Both of the
variables .theta." and e can be readily and easily varied to attain
any desired torque level or speed.
Thus, the amount of torque derived from the high-pressure fluid
acting in the system can be varied either by changing e or by
changing .theta.". In other words, the drive mechanism of the
invention can be made to have a maximum design torque output which
is several times higher than is required by the rotor or other
rotatably mounted body which is to be driven in rotation by the
drive mechanism, but the power consumption will always be exactly
equal to the power which is required. Such overdesigning can be
done at no appreciable additional cost.
Applying the foregoing considerations relative to selected
variation of speed and torque control to the system which is
depicted in FIGS. 1 and 2, it will be perceived that selective
control of these parameters can be easily obtained by providing for
any suitable means for rotating the position of the eccentric
sleeve 34 within the housing 32. For example, a simple gear drive
might be provided to the eccentric sleeve 34 and controllable from
outside the housing 32 to cause the eccentric sleeve to be rotated
to a selected position within the housing so as to vary the value
of the angle .theta.", and thus adjust the net torque developed and
the speed of the rotor as may be desired.
Another embodiment of the present invention is depicted in FIG. 5
of the drawings. Here a disk block 164 is provided and is adapted
for securement to a rotatably mounted body so as to concurrently
rotate about a rotational axis extending through point 0. The disk
block has a series of circumferentially spaced ports 166 formed
therethrough with the ports being radially spaced outwardly from
the axis of rotation by equal distances. The ports 166 are aligned
with fluid passageways extending into the rotor or other rotatable
body (not shown) to which the disk block is attached for receiving
relatively high-pressure fluid and relatively low-pressure fluid
therefrom during rotation of the body. Each port 166 communicates
with a cylindrical bore 168 which extends inwardly from the outer
peripheral surface 170 of the disk block. Each cylindrical bore 168
intersects a counterbore 172 formed in the outer peripheral
surfaces of the disk block, such counterbore being threaded to
receive a piston stop cap 174.
Disposed within each cylindrical bore 168 is a piston 176 which has
an O-ring seal 178 secured therearound for sealingly engaging the
wall of the cylindrical bore. Each of the pistons 176 has a
semispherical recess 180 formed in the radially outer surface
thereof to receive a ball 182 secured to one end of a tie rod 184.
Each tie rod 184 projects through an opening 186 formed in the
respective piston stop cap 174, and the opening 186 is sufficiently
large that each tie rod can swivel or pivot about its respective
ball 182. At its outer end, each of the tie rods 184 carries a
second ball 188 which is pinned by a pivot pin 190 to an eccentric
ring or sleeve 192 which eccentrically surrounds the disk block
164, and is eccentric with respect to the axis of rotation of both
the disk block and the rotatable body to which it is secured. Thus,
the center of curvature upon which the inner peripheral surface 194
of the eccentric ring 192 is formed is indicated by reference
character 0' in FIG. 5. The radius of the circle upon which the
several points of connection of the tie rods 184 to the eccentric
ring 192 are located is designated by reference character R in FIG.
5, and the radial distance between the center of the disk block 164
(rotational axis of the disk block and rotating body), and the
contact points between a piston 176 and its respective tie rod 184
is designated by reference character r. The length of the tie rods
is indicated by reference character d.
Surrounding the eccentric ring 192 is a cylindrical or annular
bearing member 198. The annular bearing member 198 is
concentrically located with respect to the eccentric ring 192, and
a suitable bearing race 200 is provided between the annular bearing
member and the eccentric ring so that the eccentric ring may rotate
within the bearing member. Finally, a cylindrical housing 202 of
the type hereinbefore described is provided outside of the annular
bearing member 198.
In the operation of the embodiment of the invention partially
depicted in FIG. 5, the force exerted on the eccentric ring 192 by
the pistons 176 through the tie rods 184 causes the eccentric ring
to rotate within the annular bearing member 198, and in undergoing
such rotation, to pull the disk block 164 and the rotor secured
thereto along with it. When each piston 176 has traveled the full
length of its respective cylinder, it is stopped by the respective
piston stop cap 174 partially closing the opening to that cylinder,
and its respective tie rod 184 is then pulled out by the action of
the other pistons which still have room left for outward movement.
It is this pulling action against the piston stop caps 174 by the
tie rods 184 which creates the necessary torque for turning the
disk block 164 and an associated rotatable body, such as the rotor
of an energy exchange engine.
One advantage of the use of the drive mechanism of the present
invention in a device of the type such as the energy exchange
engine is that the drive mechanism requires the diversion of a
relatively small amount of the pressurized fluid in comparison to
the total fluid throughput through the engine. For example, using
hydraulic drive units in conjunction with a typical energy exchange
engine, the bores in such an engine will typically be one-half inch
in diameter by 24 inches in length (in a pilot or laboratory size
device). The amount by which fluid is displaced by these bores into
a pair of radial cylinders forming a part of two hydraulic drive
units, and communicating with each bore at each end thereof is
about one-fourth inch each. Therefore, the percent of pressurized
liquid which is, in a sense, diverted from the uninterrupted
throughput (which would otherwise occur in the exchange engine) for
the purpose of operating the hydraulic drive units becomes
100.times. 1/4.times. 2/24 which is approximately 1 percent. As the
exchange engine is scaled up to a larger size, this percentage
becomes substantially smaller. The amount of expansion of water
when its pressure is reduced from 2,500 p.s.i.a. to 30 p.s.i.a. is
about 0.8 percent. Therefore, the hydraulic drive units can derive
a substantial part of their energy requirements from the available
work of expansion of the relatively high-pressure liquid.
Yet another embodiment of the present invention is diagrammatically
illustrated in FIG. 6 of the drawings. In this arrangement, a fixed
semieccentric sleeve 204 is placed radially outwardly of a disk
block 206 which is secured to, and rotatable with, a rotor or other
rotatably mounted body, about an axis of rotation passing through
the point 0. The direction of rotation of the disk block 206 and
rotor is indicated by the curved arrow extended around the point 0.
Close observation of the semieccentric sleeve 204 will reveal that
one-half of the inner surface 208 of the sleeve 204 is formed about
the same center of curvature 0 as is the outer peripheral surface
210 of the disk block 206. The other half of the inner peripheral
surface 208 of the semieccentric sleeve 204 is, however,
eccentrically disposed with respect to the axis of rotation of the
disk block 206 and its associated rotor, and therefore has its
center of curvature displaced from the point 0. When this
structural arrangement is employed, it is utilized in a particular
relationship to the fluid ports and passageways through the rotor
or other rotating body, which ports and passageways feed high- and
low-pressure fluid to the cylinders (not shown) disposed around the
outer periphery of the disk block 206 in the manner hereinbefore
described. Thus, this arrangement may be described as being such
that during about one-fourth of one rotational cycle of the rotor
and disk block 206, high-pressure fluid is acting upon the pistons
carried in the cylinders at the outer periphery of the disk block
206, and this portion of the rotational cycle may be referred to as
the high-pressure zone. Another quarter cycle of the rotor and disk
block 206 transpires at a time when relatively low-pressure fluid
has been passed through passageways or bores in the rotor and into
the cylinders located at the outer periphery of the disk block, and
this fraction of the rotational cycle may be referred to as a
low-pressure zone. These zones are schematically illustrated in
FIG. 6.
From what has been previously said in describing the operation of
the energy exchange engine depicted in FIG. 1, and from the dashed
line illustration of the high-pressure and low-pressure ports, 156
and 158, respectively, in the seal plates as schematically
illustrated in FIG. 3, it will be appreciated that between the time
that relatively high-pressure fluid if introduced to, and
discharged from, one of the axially extending bores or passageways
through the rotor of an energy exchange engine, and the time that
relatively low-pressure fluid is introduced to and discharged from
the same axially extending bore in the energy exchange engine, a
period of transition may be said to occur during which this bore in
the rotor is isolated from communication with either the source of
high-pressure fluid or the source of low-pressure fluid (such as
the high-pressure and low-pressure ports 156 and 158 formed in the
seal plate may be considered to be). These zones of transition from
high to low pressure may be though of as corresponding to the
island zones lying between the high-pressure and low-pressure ports
156 and 158 depicted in FIG. 3, these being denominated by
reference numerals 212 and 214 in that figure. In other words, as
each axial bore of the rotor or other rotatable body attached to a
disk block of a drive mechanism of this invention passes across an
island area between the ports used to alternately introduce high-
and low-pressure fluid to this bore, it may be thought of as
passing through a transition zone between a high-pressure zone and
a low-pressure zone.
FOr purposes of illustration, in the schematic illustration of FIG.
6, these zones of transition have been depicted as occurring during
one quarter of a complete revolution of the rotor and disk block
206, and the two zones of transition are schematically illustrated.
For this portion (one-fourth) of a complete cycle of the rotor and
disk block 206 to be utilized in traversing the two zones of
transition, it would actually be necessary to make the ports
through which high- and low-pressure fluids are introduced to the
rotor and drive mechanism (such as the ports 156 and 158 shown in
FIG. 3) of a size to communicate with each rotor bore during only
one-fourth of one period of revolution of the rotor.
It will be noted in referring to FIG. 6 that during the period of
time that cylinders and their respective pistons disposed at the
outer periphery of the disk block 206 are located opposite the
noneccentric portion of the inner peripheral surface 208 of the
semieccentric sleeve 204, no torque can be developed by reaction
forces generated by contact of piston rods with such surface since
no eccentricity is encountered during this period. The absence of
eccentricity in the inner peripheral surface 208 of the sleeve 204
is purposely made to be encountered by the pistons carried in the
peripheral cylinders of the disk block 206 at a time such that the
respective cylinders are either receiving high-pressure fluid from
a communicating high-pressure fluid port in a seal plate or the
like, and thus are in transit of the high-pressure zone, or,
alternatively, are isolated from both high- and low-pressure fluid
sources, and are in the process of moving from registry with a
relatively low-pressure fluid port toward registry with a
relatively high-pressure fluid port.
At such time as the peripheral cylinders on the disk block 206 and
the pistons reciprocably located therein are opposite the zone of
transition from high- to low pressure, the eccentricity of the
inner peripheral surface 208 of the semieccentric sleeve 204 is
such that the pistons can move outwardly, and reaction forces are
developed which tend to drive the disk block 206 in rotation in the
direction indicated by the arrow surrounding the point 0. At this
time, the cylinders at the outer periphery of the disk block 206
contain a relatively high-pressure fluid, and both they and their
communicating fluid passageways in the rotatable body attached to
the disk block 206 are isolated from the sources of the relatively
high-pressure fluid and the relatively low-pressure fluid. The
rotatable body is, however, approaching a position during its
rotational cycle such that the bores communicating with these
cylinders will next become aligned with the low-pressure port, and
low-pressure fluid will be introduced into the bores to drive out
or exhaust the high-pressure fluid to the atmosphere as has been
explained in referring to the operation of the energy exchange
engine shown in FIG. 1.
The described arrangement (in which the positive torque is
developed for driving the disk block 206 and associated rotatable
body in rotation at a time when the fluid passageways or bores in
the rotatable body are in the described transition zone between
high- and low-pressure fluid) offers the advantage that some of the
work of expansion of the relatively high-pressure fluid which would
otherwise be lost (as this fluid is exhausted to atmospheric
pressure by displacement by the entering relatively low-pressure
fluid at such time as communication is established with the
low-pressure fluid ports) is, in fact, recovered by using a portion
of such work of expansion to drive the pistons in the peripheral
cylinders outwardly against the diverging eccentric portion of the
inner peripheral surface 208 of the semieccentric sleeve 204.
Moreover, by using a part of this work of expansion for this
purpose at this time, a gradual depressurization of the relatively
high-pressure fluid-- at this time isolated in the bores or
passageways of the rotor or other rotatable body--is effected prior
to the time that these bores or passageways are placed in
communication with the low-pressure port through the seal plate,
and thus a smoother operation of the energy exchange engine or
other device in which rotational movement is developed by the drive
mechanism of the invention is effected. Also, as will be seen
momentarily, this gradual depressurization during the transiting of
the transition zone reduces the amount of negative torque which
will be developed during transit of the low-pressure zone, since
the effect of such depressurization at this stage is to lower the
pressure acting in the peripheral cylinders of the disk block 206
during the time that the eccentricity of the semieccentric sleeve
is such that negative torque is developed.
The peripheral cylinders and the pistons therein are rotated
opposite the converging eccentric portion of the inner peripheral
surface 208 of the semieccentric sleeve 204 at a time when the
bores or passageways communicating with these cylinders are
receiving relatively low-pressure fluid. Thus, as has been
described in referring to the energy exchange engine shown in FIG.
1, the axially extending bores through the rotor 10 will, at this
time, be communicated with the relatively low-pressure ports in the
seal plates at opposite ends of the rotor, so that the relatively
high-pressure fluid which has previously been entrapped in the bore
will at that time be discharged to atmospheric pressure under the
impress of relatively low-pressure fluid moving into the bore from
the registering low-pressure fluid port in the aligned seal plate.
It is during the occurrence of this type of fluid flow through
certain bores in the rotor and into communicating peripheral
cylinders on the disk block 206 that these cylinders and the
pistons which they carry may be said to be transiting the
low-pressure zone. As has been previously described, the converging
eccentricity of the surface 208 at this time develops a reaction
force producing negative torque which tends to oppose rotation of
the disk block 206 and the rotor associated therewith in the
desired direction of rotation as indicated by the arrow. However,
due to the relatively low pressure applied to the cylinders at this
time, this negative torque is small in comparison to the positive
torque developed during the passage of the peripheral cylinders and
their pistons through the transition zone from high to low pressure
as previously described. Moreover, the pressure acting on the
pistons has been even further reduced than would normally be the
case with a drive system of the type depicted in FIGS. 1, 2 and 4,
in that some of the pressure energy has been expended during the
passage of the zone of transition from high to low pressure for the
purpose of forcing the pistons outwardly at that time.
When the work of fluid expansion is more than is required to
operate the drive mechanism of the invention, the semieccentric
sleeve 204 can be further modified with respect to the
configuration of the inner peripheral surface 210 so as to allow
partial inward movement of the pistons as they pass through the
zone of transition from low pressure to high pressure. This
arrangement allows partial compression of the fluid in the bores
due to inward movement of the pistons in the peripheral cylinders
prior to the time that the bores in the rotating body are placed in
communication with the high-pressure ports through the seal plates
at opposite ends of the body. Alternatively, one can use the
hydraulic drive unit to precompress the low-pressure liquid to the
full pressure prior to communication with this high-pressure port
if the eccentricity and stroke of the pistons and piston rods moved
thereby are sufficiently dimensioned. With an arrangement of this
type, the movements of the pistons when the bores of the rotor or
other rotatable body are in communication with a high-pressure
source will provide the necessary energy which may be required to
rotate the rotor. The expansion work is utilized to precompress the
low-pressure fluid.
Although certain preferred embodiments have been herein described
in order to provide examples of the manner in which the drive
mechanism of the present invention may be constructed and, more
importantly, of the operating principles which underlie such drive
mechanism, it is to be understood that a number of changes in the
arrangement of structural elements, and in their relationship to
each other, can be made without departure from the basic principles
of the invention. Changes and innovations of this type are
therefore deemed to be circumscribed by the appended claims or
reasonable equivalents thereof.
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