The invention relates to the field of variable displacement pumps. In particular, the invention relates to an oscillating variable displacement ring pump that draws and delivers substances, such as liquids, into and out of a pump chamber by movement of a displacement ring.
BACKGROUND
Displacement pumps can take the form of gear pumps, vane-type pumps and oscillating slide pumps. With these forms of pumps, the volume of substances displaced or delivered is typically fixed due to the physical dimensions of the pumps and cannot be easily varied. It is, therefore, desirable to provide a pump that can be easily changed to vary the amount of substances displaced or delivered.
SUMMARY
An oscillating variable displacement ring pump is provided. In one embodiment, the pump can have a housing circumscribing a pump chamber. The pump chamber includes an inlet port and an outlet port. The pump chamber encases an oscillating variable displacement ring. A valve within the pump chamber contacts the ring to help isolate the outlet port from the inlet port and to separate incoming substances from outgoing substances. The pump draws and delivers substances by movement of the displacement ring within the pump chamber. When the pump chamber is sealed, ring oscillation creates a vacuum on the inlet port and pressure on the outlet port. The vacuum draws substances into the pump chamber through the inlet port while driving substances out of pump chamber through the outlet port.
In one embodiment, a crankshaft rotatably disposed within the pump housing drives ring oscillation. In this embodiment, the crankshaft comprises an input shaft and an offset shaft whereby rotation of input shaft rotates the offset shaft. The offset shaft is located inside the pump chamber and is encircled by the ring. A spacer, such as a bearing, is set on the offset shaft and rolls inside the ring as the crankshaft rotates. The diameter of the spacer and the width of the ring sidewall is chosen such that there is minimal clearance between the ring and the spacer and between the ring and the chamber sidewall.
In another embodiment, the housing can form a pump face, which opens into the pump chamber. A cover plate can attach to the housing to cover the pump face and to form an airtight seal with the pump chamber. The cover plate can attach to the housing, by attaching means including, but not limited to, bolts and screws.
In one embodiment, the pump can comprise a valve that has an anchored end and a free end. The anchored end can be pivotally attached to the pump chamber's inside wall at a position between the inlet port and the outlet port. The free end extends toward the pump chamber's centre. The valve can pivot into a recess in the pump chamber's inside wall in order to make the valve flush with the inside wall surface. During pumping, the valve free end contacts the ring and follows the ring's oscillating movement. In response to ring contact, the free end is cyclically pushed into the recess until the pushing force from the oscillating ring has passed. The ring and the valve separate the inlet port from the outlet port. The valve can be of various types or styles, including but not limited to a flapper valve, a sliding valve, a wedge valve, a reed valve and a rocking valve.
In another embodiment, the pump can include adjustable internal by-pass protection means to prevent over-pressuring and to control the output pressure of substances being pumped. The by-pass protection means can comprise, but is not limited to: (a) a check valve, a needle valve or a poppet valve located in a passageway connecting the outlet port to the inlet port, or (b) a spring mounted directly on the offset shaft to limit the pressure applied to ring against the internal wall of the pump chamber allowing substances to by-pass internally in the pump chamber past the ring. In another embodiment, the passageway valve can be controlled by a spring-loaded mechanism, such as a thumbscrew or other suitable means, to adjust and set the pressure at which the valve will open.
The pump on/off means can include, but is not limited to, an electric clutch or a mechanically engaging a gear or shaft operatively coupled to the crankshaft.
In one embodiment, the pump can provide both positive and variable displacement, wherein the volume of substances displaced by the pump can be varied, by increasing or decreasing ring diameter without affecting ring thickness or any other pump dimensions. The volume displaced by the pump is calculable and, therefore, the ring dimensions required for delivering an exact volume per revolution can also be calculated. The volume of substances displaced by the pump per crankshaft revolution is inversely proportional to the ring diameter. As the ring diameter is increased, the volume available for substances in the chamber decreases.
In another embodiment, the pump can be used with a ring of a customized size. Furthermore, the pump can be used with a kit, wherein the kit contains rings of differing diameters, allowing user to change the volume of substances displaced by the pump in order to provide the desired pumping rate.
In representative embodiments, the pump can have few moving parts to promote ease of repair. The pump can be designed with little friction loss in order to lengthen the duration of time the pump stays in calibration and to help ensure long, dependable substance delivery. To reduce wear and to help prevent unwanted or accidental adjustment, the pump can be internally adjustable and can have no exposed parts.
In a representative embodiment, the pump can have a simple design, which allows the pump: (a) to be manufactured at low cost, compared to other pumps in the field; (b) to be used for a variety of applications; and (c) to be made small and light relative to the substance it can inject. In other embodiments, the pump can be made mostly out of plastic for use in small, every day public applications such as soap injectors or agricultural chemical injectors. In further embodiments, the pump can be made with extreme precision with materials to be used in applications including but not limited to medicine, aerospace, or military applications.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational cross-section view depicting a housing of one embodiment of an oscillating ring pump.
FIG. 2 is a front elevational cross-section view depicting one embodiment of an oscillating ring pump.
FIG. 3 is a side elevational cross-section exploded view depicting the pump of FIG. 2.
FIG. 4 is a front elevational cross-section view depicting a first alternate embodiment of an oscillating ring pump.
FIG. 5 is a front elevational cross-section view depicting a second alternate embodiment of an oscillating ring pump.
FIG. 6 is a front elevational cross-section view depicting a third alternate embodiment of an oscillating ring pump.
FIG. 7 a front elevational cross-section view depicting a fourth alternate embodiment of an oscillating ring pump.
FIG. 8 is a front elevational cross-section view depicting a fifth alternate embodiment of an oscillating ring pump.
FIG. 9 is a top cross-sectional plan view depicting a pressure relief/bypass valve on the ring pump of FIG. 2.
FIG. 10 is a front elevational view depicting the oscillating ring pump of FIG. 2 with the ring located near top dead centre (“TDC”).
FIG. 11 is a front elevational view depicting the oscillating ring pump of FIG. 2 with the ring rotated about 80° from TDC.
FIG. 12 is a front elevational view depicting the oscillating ring pump of FIG. 2 with the ring rotated about 175° from TDC.
FIG. 13 is a front elevational view depicting the oscillating ring pump of FIG. 2 with the ring rotated about 240° from TDC.
FIG. 14 is a front elevational view depicting the oscillating ring pump of FIG. 2 with the ring rotated about 270° from TDC.
FIG. 15 is a front elevational cross-section view depicting a sixth alternate embodiment of an oscillating ring pump.
DETAILED DESCRIPTION OF EMBODIMENTS
Shown in FIG. 1 is a representative embodiment of housing 12 of pump 10. Housing 12 comprises pump chamber 14 having sidewall 13. In this embodiment, chamber 14 can be substantially circular in cross-section. Pump 10 comprises inlet and outlet ports 14 and 16 that provide communication between exterior side 11 of pump 10 and chamber 14. Inlet port 16 terminates in chamber inlet 17 in chamber 14. Outlet port 18 terminates in chamber outlet 19 in chamber 14. In the illustrated embodiment, pump 10 can comprise flapper valve 22 that comprises fixed end 32 and free end 30. Valve 22 can be pivotally attached to housing 12 at pivot point 34 between inlet port 16 and outlet port 18 thereby allowing valve free end 30 swing towards and away from the center of chamber 14. Housing 12 can further comprise recess 15 whereby valve 22 can swing into recess 15 and be substantially flush with chamber sidewall 13.
Referring to FIG. 2, an embodiment of pump 10 is shown with crankshaft 24 disposed at the center of chamber 14. Crankshaft 24 has a longitudinal axis that is substantially perpendicular to chamber wall 7 and is coaxially aligned with the center of chamber 14. Disposed on crankshaft 24 is offset shaft 26. Offset shaft 26 has an axis that is offset and substantially parallel to the longitudinal axis of crankshaft 24 such that offset shaft 26 moves in a circular path within chamber 14 as crankshaft 24 rotates. Annular spacer 28 is placed on offset shaft 26 and can freely rotate about offset shaft 26. In one embodiment, spacer 28 can comprise a roller bearing. In other embodiments, spacer 28 can comprise a needle bearing, a bushing or any other suitable bearing member that can rotate about offset shaft 26 as would be obvious to those skilled in the art. Disposed within chamber 14 is annular pump ring 20 such that it is placed about spacer 26. Ring 20 comprises sidewall 21 that has a thickness that can be equal to or less than the minimum distance separating the outer edge of spacer 28 and chamber sidewall 13 whereby there is minimal clearance between spacer 28 and ring 20 and between ring 20 and sidewall 13. In this manner, ring 20 can freely rotate or oscillate within chamber 14 as crankshaft 24 rotates yet maintain contact between spacer 28 and sidewall 13. In another embodiment, ring sidewall 21 can have a rectangular cross-section to maximize the contact with spacer 28 and sidewall 13.
Pump 10 can further comprise inlet check valve 42 and outlet check valve 44. Check valve 42 can include ball 46 and spring 50. Spring 50 urges ball 46 to rest on valve seat 48 thereby sealing off inlet port 16. Check valve 42 acts to prevent substances from prematurely entering chamber 14. The spring constant of spring 50 determines the required pressure to lift ball 46 off of valve seat 48 and allow substances to enter chamber 14. Similarly, check valve 44 acts to prevent substances from prematurely exiting chamber 14. The spring constant of spring 56 determines the required pressure to lift ball 52 off of valve seat 54 and allow substances to exit chamber 14. In representative embodiment, check valve 42 can be configured with a release pressure of approximately 2 p.s.i. whereas check valve 44 can be configured with a release pressure of approximately 10 p.s.i.
In further embodiments, housing 12 can comprise o-ring groove 8 and boltholes 6. An o-ring seal can be placed in groove 8 to provide a seal between housing 12 and a cover (not shown) that can be bolted to housing 12 using bolts engaging boltholes 6.
In operation, ring 20 can be an oscillating variable displacement ring. The movement of ring 20 pumps substances in and out of chamber 14 via inlet port 16 and outlet port 18, respectively. Crankshaft 24 rotates to move offset shaft 26 in a circular path. Rotation of offset shaft 26 causes ring 20 to oscillate within chamber 14. Oscillation of ring 20 creates vacuum pressure on inlet port 16 to draw substances into pump chamber 14. The vacuum pressure is greater than the release pressure of check valve 42 thereby allowing substances to enter chamber 14 via chamber inlet 17. As ring 20 moves within chamber 14, substances are pushed towards chamber outlet 19 and check valve 44. The pressure on the substances being pumped will exceed the release pressure of check valve 44 and allow substances to then exit via outlet port 18. All the while, the pressure of the substances in chamber 14 will urge free end 30 of flapper valve 22 to maintain contact with ring 20 so as to provide a barrier that prevents substances from moving towards chamber inlet 17.
By maintaining contact with ring 20, free end 30 can be pushed into recess 15 by the movement of ring 20 until ring 20 has cyclically moved past recess 15. Fixed end 32 is positioned on sidewall 13 such that flapper valve 22 covers chamber outlet 19 when pushed into recess 15 by ring 20 thereby closing off chamber outlet 19.
Referring to FIG. 3, an exploded side view of pump 10 is shown. In this embodiment, crankshaft 24 can be operatively coupled to input shaft 29 that passes through opening 27 in housing 12 and can be supported by a pair of bearings 31. Bearings 31 can be of the tapered roller variety or any other suitable replacement such as ball bearing, needle bearing, bushing or any other bearing as well known to those skilled in the art. Pump 10 can further include seal 25 disposed around crankshaft 24 to seal off chamber 14. When assembled, spacer 28 is set upon offset shaft 26 and ring 20 is set upon spacer 28. O-ring 7 can be placed in groove 8. Cover 33 is placed against o-ring 7 on housing 12 to enclose and seal chamber 14. Cover 33 can be secured into position with retainer ring 35 fastened to housing 12 by bolts 5 threaded into boltholes 6. Cover 33 can be made of any suitable material that can withstand the pressure of substances being delivered by pump 10. In a representative embodiment, cover 33 can be made of transparent plexiglas of suitable thickness so as to enable visual inspection of pump 10 when in operation.
Referring to FIG. 4, another embodiment of pump 10 is shown. In this embodiment, flapper valve 22 can further include reed valve 36. Reed valve 36 has fixed end 40 and free end 38. Reed valve 36 can be positioned between flapper valve 22 and ring 20. Reed valve 36 can be made of flexible material, such as spring steel or other suitable materials as known to those skilled in the art. The inclusion of reed valve 36 can enhance the seal made by flapper valve 22 when it contacts ring 20.
In another embodiment, pump 10 can include biasing means to urge flapper valve 22 to contact ring 20. In one embodiment, the biasing means can comprise spring 23 or it can be any other suitable mechanism as known to those skilled in the art.
Referring to FIG. 5, another embodiment of pump 10 is shown. In this embodiment, pump 10 can use wedge 58 as a valve as described above. Wedge 58 has fixed end 62 that is pivotally attached to housing 12 at pivot point 64 and free end 60 that contacts ring 20. In this embodiment, spring 66 urges wedge 58 towards ring 20. Spring 66 is secured in place by spring sleeve 68 and bolt 70 threaded into opening 74 in housing 12. Shim 72 can be placed between spring 66 and bolt 70. Shim 72 can be varied in thickness to vary the pre-load tension on spring 66, that is, thinner shims will reduce the tension whereas thicker shims will increase the tension.
Referring to FIG. 6, another embodiment of pump 10 is shown. In this embodiment, slider valve 76 can be used to separate or isolate inlet 16 from outlet 18. Slider valve 76 comprises valve face 77 that contacts ring 20. Slider valve 76 is slidably disposed in valve guide opening 80 in housing 12 that is configured to receive slider valve 76. Spring 78 can be disposed within opening 80 and valve 76 as illustrated to provide biasing means to urge slider valve 76 to the center of chamber 14 and to have slider valve face 77 maintain contact with ring 20. In this embodiment, slider valve 76 can be configured to be substantially perpendicular to exterior surface 11 of housing 12.
Referring to FIG. 7, another embodiment of pump 10 is shown. In this embodiment, pump 10 can have slider valve 82 slidably disposed in valve guide opening 90 disposed in housing 12 to receive slider valve 82. Slider valve 82 can further comprise ball end 84 with valve shoe 86 rotatably coupled thereon. Shoe 86 can rotate on ball end 84 to maintain contact with ring 20 as ring 20 oscillates within chamber 14. Spring 88 can be disposed within opening 90 and valve 82 as illustrated to provide biasing means to urge slider valve 82 to the center of chamber 14 and to have slider valve shoe 86 maintain contact with ring 20.
Referring to FIG. 8, another embodiment of pump 10 is shown. In this embodiment, slider valve 92 and valve guide opening 94 disposed at an angle with respect to exterior surface 11 of housing 12. In a representative embodiment, slider valve 94 and opening 94 are canted at an angle of approximately 10° off of vertical. In this embodiment, slider valve 92 can include opening 97 configured to receive valve shoe 98 that maintains contact with ring 20 as it rotates within chamber 14. In this embodiment, shoe 98 can be semi-circular in cross-section and can have a concave contact surface for contacting ring 20. Spring 96 can be disposed within opening 94 and valve 92 as illustrated to provide biasing means to urge slider valve 92 to the center of chamber 14 and to have slider valve shoe 98 maintain contact with ring 20.
Referring to FIG. 9, another embodiment of pump 10 is shown. In this embodiment, pump 10 can comprise passageway 100 disposed in housing 12 to provide means for controlling the output pressure or amount of substances delivered by pump 10. In the illustrated embodiment, housing 12 can comprise passageway 99 that provides communication between passageway 100 and the passageway that connects chamber outlet 19 to output port 18. Passageway 99 can further comprise valve seat 108 for receiving ball valve 106. Biasing means can be provided to urge ball valve 106 against valve seat 108 to close off passageway 99. In the illustrated embodiment, the biasing means can include thumbscrew 104, spring 110 and spring sleeve 112. Spring 110 and spring sleeve 112 can be slidably disposed within opening 114 of thumbscrew 104. The output pressure of substances delivered by pump 10 is dependent on the pressure required to lift ball valve 106 off of valve seat 108. The more thumbscrew 104 is threaded into housing 12, the more spring 110 is compressed to increase the pressure required to open ball valve 106. The more thumbscrew 104 is threaded out of housing 12, the less spring 110 is compressed thereby decreasing the pressure to open ball valve 106. In a further embodiment, passageway 100 can comprise access port 101 and plug 102 to close off port 101 during operation of pump 10. It should obvious to those skilled in the art that means other than a ball valve can be used to control the output pressure of substances delivered by pump 10 such as a needle valve as well as any other suitable means.
Referring to FIGS. 10 to 14, operation of an embodiment of pump 10 is illustrated. In FIG. 10, pump 10 is shown with ring 20 at approximately top dead center (“TDC”). For the purpose of these illustrations, substances are contained in pump chamber 14 in this initial condition. Pump 10 begins to operate when input rotational power is applied to crankshaft 24. The input rotational power is applied to an input shaft (not shown) operatively attached to crankshaft 24. The input rotational power can be obtained from any suitable source such as a motor or from rotating shafts that are operatively coupled to the input shaft, either by meshed gears, a belt and pulleys, a chain and sprockets or any other suitable means as well known to those skilled in the art. In the illustrated embodiment, crankshaft 24 can rotate clockwise as shown in chamber 14 thereby allowing flapper valve 22 to move away from recess 15. It should be obvious to one skilled in the art, however, that pump 10 can be assembled in a mirrored configuration whereupon crankshaft 24 can rotate in a counter clockwise direction.
Referring to FIG. 11, ring 20 is at approximately 80° rotated from TDC. In this position, flapper valve 22 has moved away from recess 15 to expose chamber outlet 19. Substances in pump chamber 14 are forced through chamber outlet 19 and exit through check valve 44 and output port 18. As ring 20 rotates clockwise, pump chamber inlet side 14a is formed and begins to create a vacuum to draw in substances through inlet port 16, check valve 42 and chamber inlet 17.
Referring to FIG. 12, pump ring 20 is shown at approximately 175° rotated from TDC. In this position, pump chamber inlet side 14a is approximately the same volume as pump chamber outlet side 14b. As ring 20 rotates clockwise, the volume of pump chamber outlet side 14b decreases thereby forcing substances through chamber outlet 19 to exit through check valve 44 and outlet port 18. Flapper valve 22 acts as a barrier between pump chamber outlet side 14b and pump chamber inlet side 14a. As crankshaft 24 continues to rotate clockwise, pump chamber inlet side 14a increases in volume thereby drawing in more substances in through chamber inlet 17.
Referring to FIG. 13, pump ring 20 is shown at approximately 240° rotated from TDC. In this position, the volume of pump chamber outlet side 14b has decreased and flapper valve 22 has begun to retreat back into recess 15 to close off chamber outlet 19. The volume of pump chamber inlet side 14a continues to increase to draw in more substances through chamber inlet 17.
Referring to FIG. 14, pump ring 20 is shown at approximately 270° rotated from TDC whereby the volume of pump chamber outlet side 14b has been decreased to nearly zero. Flapper valve 22 is almost fully retracted into recess 15 to close off chamber outlet 19. As pump ring 20 continues to move clockwise to TDC, the pumping process continues in the manner described whereby substances are drawn into and pumped out of pump chamber 14 simultaneously with each revolution of crankshaft 24. The volume of substances displaced by pump 10 in each revolution of crankshaft 24 is a function of the diameter of ring 20. As the diameter of ring 20 is increased, the amounts of substances drawn in and expelled by pump 10 decreases as the available volume for pump chamber inlet and outlet sides 14a and 14b has decreased. Similarly, as the diameter of ring 20 is decreased, the amounts of substances drawn in and expelled by pump 10 increases as the available volume for pump chamber inlet and outlet sides 14a and 14b has increased.
In another embodiment of pump 10, pump 10 can be provided with a kit having a multiple number of rings 20 in various diameters but all having sidewall 21 of the same thickness. In this fashion, pump 10 can be easily configured to change the amount of substances it can displace or deliver simply by changing ring 20 of one diameter for another ring 20 having a different diameter. In this regard, a pump having variable displacement can be provided.
Referring to FIG. 15, a side view of pump 10 is shown. In this embodiment, crankshaft 24 can be operatively coupled to input shaft 29 that passes through opening 27 in housing 12 and can be supported by a pair of bearings 31. Disposed on the end of offset shaft 26 is opening 128 that can receive offset shaft 126 disposed on crankshaft 120. Crankshaft 120 can be rotatably disposed within housing cover 116 that can be, in turn, fastened to housing 12 using bolts, screws or any other suitable means. O-ring 7 can be placed between housing 12 and housing cover 116 to seal off chamber 14. Crankshaft 12 can be operatively coupled to output shaft 122 which can be supported in shaft opening 118 of housing cover 116 by bearings 124. Bearings 31 and 124 can be of the tapered roller variety or any other suitable replacement such as ball bearing, needle bearing, bushing or any other bearing as well known to those skilled in the art. Output shaft 122 can be used in any number of ways to provide rotational power to other devices. In one embodiment, one or more pumps 10 can be connected in tandem whereby the input shaft of one pump 10 is operatively coupled to the output shaft of a previous pump 10. In this fashion, different substances can be pumped simultaneously at the same, one substance per pump in the tandem.
In another embodiment, two or more pumps can be connected in tandem to pump the same substance thereby increasing the amount of substances that can be delivered per revolution of the pump crankshafts.
In a further embodiment, an input manifold, as well known to those skilled in the art, can be used to collectively feed the input ports of the tandem-connected pumps from a single source of substances.
In yet another embodiment, an output manifold can be used to connect the output ports of the tandem-connected pumps to a single output whereby all of the pumped substances are delivered from a single output port.
In yet a further embodiment, the offset shafts of the tandem-connected pumps can be rotationally spaced apart from one another with respect to the longitudinal axis of the crankshafts. For example, in a two tandem pump configuration, the offset shafts can be spaced approximately 180° apart. For a three tandem pump configuration, the offset shafts can be spaced approximately 120° apart, and so on. By configuring the offset shafts in this manner, especially when using an output manifold, the pulsing of delivered substances that naturally occurs with a single pump can be reduced or smoothed out in the delivery of substances exiting the output manifold.
Although a few embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention. The terms and expressions used in the preceding specification have been used herein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims that follow.
Patent Application
20070297919
