GB1603175A - Energy transfer devices - Google Patents

Description

(54) IMPROVEMENTS RELATING TO ENERGY TRANSFER DEVICES (71) I, CHARLES ALPHONSUS MUL VENNA, a Canadian Citizen, of 129, Cairn Grove, Kingston, Ontario, Canada, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed to be particularly described in and by the following statement:- This invention relates to an improvement in energy transfer devices of the type in which the velocity of a fluid containing conduit is varied along the length of the conduit to generate fluid flow or pressure.

BACKGROUND OF THE INVENTION The phenomenon of water hammer in a long column of fluid has long been recognized. It is produced by a change in the velocity of a fluid in a conduit and results from the conversion of fluid kinetic energy to a static pressure energy. An instantaneous change in velocity in an incompressible fluid causes an infinite pressure rise. In a real, compressible fluid, the pressure rise is finite but may be considerably greater than the normal working pressure of a system and is not instantaneous at all points along the fluid column, but rather progresses along a column as a wave with the velocity of sound in the column. Depending upon the end conditions of the column, the wave may be reflected as a positive or a negative wave. In a closed, tuned system, compounding of incident and reflected waves results in extremely high pressures.

This principle may be used as the basis of a fluid pump or other fluid energy transfer device. In a pump application, a portion of an elongated conduit, containing fluid, is supported for oscillatory movement. One end of the conduit is connected to a source of fluid while the other end is connected to an outlet. At least one flow restrictor, which may be a check valve, is placed anywhere in the conduit. Oscillation of a portion of the conduit will cause the velocity of the conduit to vary along its length. The velocity of the contained fluid, with respect to the adjacent conduit, will then vary along the length of the conduit thereby causing pressure waves to progress along the conduit resulting in a net fluid displacement in the direction permitted by the flow restrictor.

Such an arrangement gives rise to a number of difficulties. In practical terms there is the problem of oscillating one portion of a continuous conduit while another portion is fixed. There is the problem of dealing with gas liquid separation of the fluid column and there is the problem of theoretically predicting the output for design purposes.

United States Patent No. 2,936,713 granted to John C. Fisher on May, 17, 1960 described a fluid pump based upon the water hammer principle. Fisher describes a manner of supporting the conduit for both rectilinear and rotary oscillatory movement.

Fisher's approach to solving the first problem, that is of oscillating one portion of a conduit while another portion remains fixed, is to use flexible sections of tubing formed of polymeric materials such as nylon and those known by the trade marks Teflon and Saran. Such materials have limited physical properties and limit the pump to either low flows or low pressures.

The present invention is concerned with providing an improved method of oscillating one portion of a conduit while another portion remains fixed thereby providing an energy transfer device which retains the principal advantages of the Fisher pump but which, in addition, has a greatly extended life and range of application, is reliable, and has a predictable output.

The present invention may be broadly described as an energy transfer device comprising, a tube of selected length continuously coiled having at least a portion in the form of an open helix with at least one helical turn, said tube having at least one of its ends adapted for connection in fluid communication with an external fluid system; means fixedly anchoring the helical portion at a first position thereon to a supporting structure, said helical portion at a second position spaced from said first position axially along the tube being movable in an arc about the axis of the helix, and means for oscillating said tube at said second position about the axis of the helix whereby there results a progressive change in axial tube velocity along the helical portion of the tube from one to the other of said first and second positions.

The invention may be performed in a number of ways specific embodiments of which will now be described with reference to the accompanying drawings in which: Figures 1, 2 and 3, illustrate diagrammatically the spring connections in different applications; Figures 4 and 5 illustrate the manner in which the embodiment of Figure 3 may be connected to impact devices; and Figure 6 is a more detailed view illustrating a practical construction of a pump aspect of the energy transfer device.

Figure 1 illustrates, diagrammatically, a fluid energy transfer device as applied to a pump. It is comprised of an elongated fluid conduit 10 having an inlet section 11, a central section 12, and an outlet section 13.

Sections 11, 12 and 13 are formed into helical coils and are unitary. Central section 12, as shown in Figure 6 discussed below, is mounted for angular oscillation about the coil axis.

Inlet section 11 has an end 16, remote from section 12, connected to a source of fluid (not shown) and is adapted to be held stationary while section 12 is oscillated about the coil axis. Similarly, outlet section 12 has an end 17 remote from section 12 connected to an external fluid circuit (not shown) and held stationary while section 12 is oscillated about the coil axis. Inlet section 11 and outlet section 13 are each in the form of helical coils, as mentioned above, to provide a torsional spring connect in between their respective ports and central section 12.

The term spring connection is intended to refer to a mechanical contrivance which provides a required degree of flexibility regardless of the material of construction.

End 16 of inlet section 11 and end 17 of outlet section 13 are provided with the fluid rectifier means 18 and 19, respectively, which may be in the form of check valves or flow restrictors providing less resistance to flow in one direction than in the other direction.

Thus, oscillation of central section 12 about the coil axis will generate a pressure wave in the conduit and the fluid rectifiers 18 and 19 will permit a net flow of fluid from the inlet 16 to the outlet 17.

It is important to realise that in order to generate the wave in the conduit, the fluid velocity with respect to the adjacent conduit must vary along the length of the conduit.

This is achieved, in this embodiment, by fixing the remote ends 16 and 17 of inlet and outlet sections 11 and 13, respectively, while oscillating section 12 about the coil axis. As indicated later, however, only one end need be held. In so doing, the axial velocity of the conduit varies from zero at its ends to a maximum in the central section 12. As a result, the fluid velocity with respect to the adjacent conduit will vary along the length of the conduit.

It should also be appreciated that central section 12 need not be lengthy in relation to the overall length of the conduit or in relation to the length of the spring connections. It only need be as long as is required to be properly clamped to the oscillating device so that in practice it may be relatively short.

The spring connection provides improved design and operation since the position of every point on the conduit can be defined at any instant thereby allowing for accurate computation of output and of stresses at any point in the conduit wall. The connection permits the use of rigid materials. This considerably increases the capacity of the device in terms of flows or pressures. It has been found that in smaller pump units, the output can be increased by a factor of about four while in larger pump units, the output can be increased by a factor of about four while in larger pump units: the output can be increased by a factor of about ten. This results from the much higher sound velocity in the fluid contained in a rigid conduit as opposed to that of a flexible conduit and the ability of rigid materials to withstand greater stresses. Rigid ferrous materials, unlike polymers have a well defined fatigue stress limit and, thus, it is possible to design a conduit of infinite life. It follows that the range of applications can be vastly increased.

The use of polymer materials (even for end connections only) limits the device to maximum outlet pressures in the order of 150 psi and flow rates in the order of a few gallons per minute. In distinction, the use of spring connections using rigid materials enables any present pumping application to be covered - from thousands of gallons per minute at low pressures to thousands of pounds per square inch at low flows. The extended choice of materials permits high and low temperature applications, zero contamination applications and the handling of dangerous and exotic fluids.

Air liquid separation in a fluid column results from the fact that liquids contain dissolved gases and if the pressure on the liquid is reduced below atmospheric pressure, these gases separate from the liquid to form large bubbles. Since very low pressures are encountered in certain applications, the bubbles would form and act as energy absorbers and may result in a complete loss of pump output. This problem is solved by using a conduit winding having a continuous rise to permit the bubbles to move along the conduit out of the pump section. The simplest windings that permit a continuous rise in the conduit is a vertical helix as shown in Figure 1. A vertical conical spiral winding as shown in Figure 2 will permit a more compact design by reversing successive conical spirals and laying these on top of each other.

The spring inlet and outlet connections may be formed integrally with the central sections or may be made separately and connected to the central section. More importantly, the spring connections may be constructed of rigid materials and designed to provide the desired degree of flexibility.

Rigid ferrous materials have well defined fatigue stress limits and it is thus possible to design a unit of infinite life in accordance with recognised engineering methods.

Reference will now be made to Figure 6 which illustrates in greater detail the structure of the pump.

The pump 40 includes a housing shown in part as reference numeral 42, and a shaft 44 vertically mounted in the housing for oscillatory movement about its axis. The shaft is journalled in the housing in bearings section 46 and 48. The shaft is formed with a stepped portion or drum 50 to which is secured central section 54 of a fluid conduit 52. As with Figure 1, the conduit is formed with integral inlet section 56 and outlet section 58. The conduit, formed into a vertical helix, may be secured to the drum 50 by being received in a helical groove in the drum or by means of a conduit clamping bar 60 which overlies the coils of the central section 54 of the conduit 52 and is secured to the drum by means of screws 62. Any other suitable means may be used to secure the conduit to the drum provided the oscillatory movement is efficiently transmitted.

Any suitable means may be used to oscillate shaft 44 and in this connection reference is made to the Fisher patent.

Figure 6 shows a crankarm 64 secured to the lower end of shaft 44. Crankarm 64 may be connected to a motor (not shown) by way of a connecting rod in a manner well known to those skilled in such field.

It will be seen that the ends 70 and 72 of inlet and outlet sections 56 and 58, respectively, remote from the central section 54, are secured to housing 42 by means of brackets 74, 76. Furthermore the' inlet and outlet sections are free of the drum and are thus free to elastically deform in response to the oscillations. A check valve 78 connects end 70 to a supply of fluid while a check valve 80 connects end 72 to an external circuit or to an outlet port.

As mentioned earlier, only one of the conduit need be fixed while the central section is oscillated in order to produce the desired pressure wave in the fluid.

An arrangement such as that described above may be used to pump slurries or to transfer power. The latter would be the hydraulic analogy of a D.C. electrical generator.

A similar arrangement, without check valves, may also be used to transfer power.

Oscillation of the central section will result in alternating forward and reverse fluid flow. The reverse is also true, i.e., forward and reverse fluid flow in the conduit will cause oscillation of the central section and, thus, the output may be used to drive a similar unit that acts as a motor. In this mode, the unit is the hydraulic analogy of a single phase A. C. electrical generator. A number of units may be used to generate multi-phase power.

An arrangement without check valves may be used to generate alternating forward and reverse fluid flow and corresponding application of a force against a closed end of the conduit as applied for example to a jack hammer or stamping press. As shown in Figure 3, such a unit would include an elongated conduit 90 having one closed end 92 and the other end 94 connected to an impact device. The conduit has a first portion 96 adapted to be oscillated and a second portion 98 interposed between end 94 and portion 96 formed to provide the spring connection. As with the previous embodiment, the conduit is a vertical helical coil.

End 94 may be closed as shown in Figure 4, by the face 100 of a piston 102 reciprocably mounted in a cylinder 104 located in the same or separate housing. The piston is biased in one direction, by a spring 106. An impact device is connected to the other end 108 of piston 102. It will be understood that oscillation of the first portion of the conduit will generate pressure waves which will impart a force upon piston 102.

Alternatively end 94 of the conduit may be closed as shown in Figure 5 and serve as the impact device itself.

It will be understood that, as with the previous embodiment, the reverse operation is true.

WHAT I CLAIM IS: 1. An energy transfer device compris

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (22)

**WARNING** start of CLMS field may overlap end of DESC **. dangerous and exotic fluids. Air liquid separation in a fluid column results from the fact that liquids contain dissolved gases and if the pressure on the liquid is reduced below atmospheric pressure, these gases separate from the liquid to form large bubbles. Since very low pressures are encountered in certain applications, the bubbles would form and act as energy absorbers and may result in a complete loss of pump output. This problem is solved by using a conduit winding having a continuous rise to permit the bubbles to move along the conduit out of the pump section. The simplest windings that permit a continuous rise in the conduit is a vertical helix as shown in Figure 1. A vertical conical spiral winding as shown in Figure 2 will permit a more compact design by reversing successive conical spirals and laying these on top of each other. The spring inlet and outlet connections may be formed integrally with the central sections or may be made separately and connected to the central section. More importantly, the spring connections may be constructed of rigid materials and designed to provide the desired degree of flexibility. Rigid ferrous materials have well defined fatigue stress limits and it is thus possible to design a unit of infinite life in accordance with recognised engineering methods. Reference will now be made to Figure 6 which illustrates in greater detail the structure of the pump. The pump 40 includes a housing shown in part as reference numeral 42, and a shaft 44 vertically mounted in the housing for oscillatory movement about its axis. The shaft is journalled in the housing in bearings section 46 and 48. The shaft is formed with a stepped portion or drum 50 to which is secured central section 54 of a fluid conduit 52. As with Figure 1, the conduit is formed with integral inlet section 56 and outlet section 58. The conduit, formed into a vertical helix, may be secured to the drum 50 by being received in a helical groove in the drum or by means of a conduit clamping bar 60 which overlies the coils of the central section 54 of the conduit 52 and is secured to the drum by means of screws 62. Any other suitable means may be used to secure the conduit to the drum provided the oscillatory movement is efficiently transmitted. Any suitable means may be used to oscillate shaft 44 and in this connection reference is made to the Fisher patent. Figure 6 shows a crankarm 64 secured to the lower end of shaft 44. Crankarm 64 may be connected to a motor (not shown) by way of a connecting rod in a manner well known to those skilled in such field. It will be seen that the ends 70 and 72 of inlet and outlet sections 56 and 58, respectively, remote from the central section 54, are secured to housing 42 by means of brackets 74, 76. Furthermore the' inlet and outlet sections are free of the drum and are thus free to elastically deform in response to the oscillations. A check valve 78 connects end 70 to a supply of fluid while a check valve 80 connects end 72 to an external circuit or to an outlet port. As mentioned earlier, only one of the conduit need be fixed while the central section is oscillated in order to produce the desired pressure wave in the fluid. An arrangement such as that described above may be used to pump slurries or to transfer power. The latter would be the hydraulic analogy of a D.C. electrical generator. A similar arrangement, without check valves, may also be used to transfer power. Oscillation of the central section will result in alternating forward and reverse fluid flow. The reverse is also true, i.e., forward and reverse fluid flow in the conduit will cause oscillation of the central section and, thus, the output may be used to drive a similar unit that acts as a motor. In this mode, the unit is the hydraulic analogy of a single phase A. C. electrical generator. A number of units may be used to generate multi-phase power. An arrangement without check valves may be used to generate alternating forward and reverse fluid flow and corresponding application of a force against a closed end of the conduit as applied for example to a jack hammer or stamping press. As shown in Figure 3, such a unit would include an elongated conduit 90 having one closed end 92 and the other end 94 connected to an impact device. The conduit has a first portion 96 adapted to be oscillated and a second portion 98 interposed between end 94 and portion 96 formed to provide the spring connection. As with the previous embodiment, the conduit is a vertical helical coil. End 94 may be closed as shown in Figure 4, by the face 100 of a piston 102 reciprocably mounted in a cylinder 104 located in the same or separate housing. The piston is biased in one direction, by a spring 106. An impact device is connected to the other end 108 of piston 102. It will be understood that oscillation of the first portion of the conduit will generate pressure waves which will impart a force upon piston 102. Alternatively end 94 of the conduit may be closed as shown in Figure 5 and serve as the impact device itself. It will be understood that, as with the previous embodiment, the reverse operation is true. WHAT I CLAIM IS:

1. An energy transfer device compris

ing, a tube of selected length continuously coiled having at least a portion in the form of an open helix with at least one helical turn, said tube having at least one of its ends adapted for connection in fluid communication with an external fluid system; means fixedly anchoring the helical portion at a first position thereon to a supporting structure, said helical portion at a second position spaced from said first position axially along the tube being movable in an arc about the axis of the helix, and means for oscillating said tube at said second position about the axis of the helix whereby there results a progressive change in axial tube velocity along the helical portion of the tube from one to the other of said first and second positions.

2. A device as claimed in claim 1, including first and second fluid flow restrictors in said tube respectively at opposite sides of said helical portion.

3. An energy transfer device as claimed in claim 1 wherein the other end of said conduit is closed and wherein said one end connects to the external fluid system.

4. An energy transfer device as claimed in any one of the preceding claims further including a shaft journalled on the supporting structure for oscillatory movement about an axis co-incidental with the axis of the helix and means securing said helical portion of said tube at said second position to said shaft for movement therewith.

5. An energy transfer device as claimed in claim 4 wherein said helically coiled tube continues beyond said second position to a third position and wherein the tube between said second and third positions is rigidly secured to said shaft for movement therewith.

6. An energy transfer device as claimed in claim 5 as dependent on claim 3 wherein said continuing portion of the helically coiled tube terminates in a closed end of said tube and wherein the one end of said tube is adapted for connection in fluid flow communication with a fluid power impact device.

7. An energy transfer device as claimed in claim 5 wherein said helically coiled tube continues beyond said third position to a fourth position and wherein said tube, at said fourth position, is fixedly secured to said supporting structure.

8. An energy transfer device as claimed in claim 5 as dependent on claim 2 wherein the first and second fluid flow restrictor means are adjacent respectively said first and fourth positions.

9. An energy transfer device as claimed in claim 8 wherein said fluid flow restrictor means comprise one-way flow check valves.

10. A device for use in transferring energy from one to the other of a tube and a fluid therein comprising: (a) a supporting structure; (b) a tube having respective first and second opposite ends and sufficiently rigid so as not to expand radially during normal operating pressure of a fluid in the tube, at least a major portion of the length of said tube being in the form of an open helix providing first and second contiguous helical coil portions on a common axis and each consisting of a selected length of said tube;; (c) means associated with said supporting structure and said first helical portion alternately torsionally twisting such helical portion in opposite directions a limited amount about the axis of the helix, said torsional twisting progressively increasing and decreasing the radius of curvature of the tube in such helical portion from one end to the other thereof whereby there results a progressive change in axial tube velocity; and (d) means associated with said second helical portion and said frame preventing bending of the tube in said second helical portion.

11. An energy transfer device as defined in claim 1, the other end of said conduit being closed whereby longitudinal oscillation of said portion of said conduit resulting in alternating forward and reverse fluid flow.

12. An energy transfer device as defined in claim 1, the other end of said conduit being closed whereby alternating forward and reverse fluid flow resulting in longitudinal oscillation of said portion of said conduit.

13. An energy transfer device as defined in claim 1, the other end of said conduit being open and adapted to be in fluid communication with an external fluid system whereby longitudinal oscillation of said portion of said conduit resulting in alternating forward and reverse fluid flow.

14. An energy transfer device as defined in claim 1, the other end of said conduit being open and adapted to be in fluid communication with an external fluid system whereby alternating forward and reverse fluid flow resulting in longitudinal oscillation of said first portion of said conduit.

15. An energy transfer device as defined in claim 1, said first and second portions of said conduit being unitary and helically coiled and said second portion forming a torsional spring connection.

16. An energy transfer device as defined in claim 6, further including: a housing; a pivotable shaft journalled in said housing and defining a pivot axis; a drum concentrically mounted on said shaft for movement therewith; said portion being coiled on said drum and secured thereto for movement therewith; said one end of said conduit being secured to said housing.

17. An energy transfer device as defined in claim 16, said drum having on its peripheral surface a helical groove for receiving said helically coiled first portion.

18. An energy transfer device as defined in claim 17, said drum having on its circumferential surface a series of steps, each step having a helical groove for receiving said first portion of said conduit.

19. An energy transfer device as defined in claim 18, said one end of said conduit extending outwardly of said housing and adapted to be connected to an impact tool.

20. An energy transfer device as defined in claim 18, the other end of said conduit extending outwardly of said housing and adapted to be connected to an impact tool for driving same.

21. An energy transfer device as defined in claim 18, both ends of said conduit extending outwardly of said housing and adapted to be connected to an impact tool for driving same.

22. A fluid energy transfer device substantially as described with reference to the accompanying drawings.