US 3048121 A
Description (OCR text may contain errors)
Aug. 7, 1962 J. M. SHEESLEY 3,048,121
HYDRAULIC ACTUATED PUMP Filed April 14, 1960 2 Sheets-Sheet 2 John M Jfieea/e 4 INVENTOR.
BY @K ite flttes Filed Apr. 14, 1960, Ser. No. 22,233 3 Claims. (1. 103-152) This invention relates to new means for pumping fluids, and more particularly it relates to new valve actuating means for operation of hydraulically actuated flexible diaphragm pumps.
The pumps of this invention are particularly well adapted for use in handling highly corrosive and highly abrasive fluids at high pressures, and with maximum efficiencies. Pumps for such applications must normally be constructed of stainless steel or other corrosive resistant or abrasion resistant metals, but such materials are quite expensive. In other applications, foamy liquids are pumped, which tend to deposit air in the pumping system, thereby interfering with its operation. The pumps of this invention are also particularly useful as proportioning and metering pumps, in that the valve actuating means used allows extremely accurate control of the volume handled by the pump. According to the present in vention, such problems are avoid by utilizing a pump containing a diaphragm, preferably in the form of a flexible walled conduit, such as may be made of natural or synthetic rubber, so that the main body of the pump is isolated from the corrosive or abrasive fluid being pumped. A non-corrosive hydraulic fluid is applied to one side of the diaphragm, as to the outside of the flexible conduit, under pressure suflicient to flex the diaphragm to apply a pressure to the corrosive or abrasive fluid on the other side of the diaphragm, so that the corrosive or abrasive fluid is pumped. Also according to this invention, valving means are provided for alternately applying and releasing the pressure of the hydraulic fluid in a manner conducive to the most eflicient and economical operation of the pump. This is accomplished by providing valving means which is responsive to the degree of flexing of the diaphragm, as will be evident housing 12, closed at its ends by heads 14 and 16. Heads 14 and 16 are each provided with means for sealingly retaining a flexible diaphragm 18, which is in the form of an elongated tubular member. Tubular member 18 sealingly engages a boss 20 projecting axially from head 16, being secured thereto by means of a clamp ring 22. Similarly, the other end of tubular member 18 sealingly engages a boss 24 projecting axially from head 14, being secured thereto by a clamp ring 26.
Head 14 is provided with means for admitting pumped fluid to the interior of tubular member 18 and means for exhausting pumped fluid therefrom, such means constituting, in the embodiment shown in FIGURE 1, an axial passageway 28 having in communication therewith an inlet conduit 30, containing a check valve 32, and an exhaust conduit 34, containing a check valve 36.
Head 16 is provided with means for admitting hydraulic fluid to the annular space 38 formed between 3,848,121 Patented Aug. 7, 1962 "ice tubular conduit 18 and cylindrical housing 12, and for exhausting hydraulic fluid from said annular space. Such means comprises a fluid passageway 40 in communication with the annular space 38 and with a fourway valve 42, which provides means for controlling the direction of flow of hydraulic fluid through passageway 40.
Tubular member 18 is provided, intermediate its ends, with a flexible ring portion 44, containing an aperture 46 extending longitudinally thereof. A cable or wire, or other substantially non-elastic flexible member 48, extends through aperture 46, and longitudinally of the cylindrical housing 12, from a point of attachment, by means of element 50, to head 14, through an aperture 52 in head 16. Aperture 52 forms means for communication between annular space 38 and a pilot valve cavity 54 in head 16. A pilot valve 56 is slidingly and sealingly received in cavity 54, and is adapted to be moved longitudinally of cylindrical housing 12 and tubular member 18, by longitudinal movement of cable 48, the free end of which is attached to the valve. A pilot fluid opening 58 is provided in one side of pilot valve cavity 54, and is adapted to be closed by said pilot valve in one position of said pilot valve, and to be open in another position of said pilot valve. Pilot valve 56 is biased toward said one position wherein pilot fluid opening 58 is closed, by means of a spring 60, and is adapted to be moved to said other position, wherein the pilot fluid opening is opened, by means of application of tension to cable 48. Pilot valve 56 is provided with apertures 62 extending longitudinally therethrough to provide means for admitting fluid to the pilot fluid opening.
Means are provided for supplying the fluid to be pumped to tubular member 18 at relatively low pressure, say 10 to 25 p.s.i.g. Such means may comprise a low pressure centrifugal pump 64, which supplies fluid to inlet conduit 30.
Hydraulic fluid for operating the pump of this invention is provided from a convenient source of high pressure fluid, such as a reservoir 66 and a pump 68. Pump 68 furnishes hydraulic fluid at high pressure to four-way valve 42, which contains a spool '70 which is biased toward the right by spring 71. At the position of the valve shown in FIGURE 1, hydraulic fluid at high pressure may flow through a fluid conduit 72 and through fluid passageway 40 into annular space 38.
In operation, tubular member 18 is filled with the fluid to be pumped by centrifugal pump 64 or other convenient low pressure source. When tubular member 18 is filled, pilot valve 56 and piston 70 of four-way valve 42 are in the position shown in FIGURE 1. Hydraulic fluid is then supplied to the annular space 38 by means of pump 68. This fluid will normally be supplied at a comparatively high pressure, say 1000 p.s.i.g. or higher. The force of this pressure on tubular member 18 will cause this member to begin to collapse, forcing out the fluid therein through valve 36 and exhaust conduit 34. As tubular member 18 collapses, flexible ring portion 44 also collapses, applying a lateral force to cable 48, which force is resolved into a tension on the cable, causing pilot valve 56 to move against its biasing spring 60. This movement is continued until pilot fluid opening 58 is exposed, so that hydraulic fluid flows through aperture 52, pilot valve cavity 54, apertures 62, pilot fluid opening 58, and pilot fluid conduit 74, into the end of fourway valve 42, whereby the spool 70 is moved to the left, as shown in FIGURE 1, against the biasing spring 71, closing off flow of high pressure fluid from pump 68 through conduit 72, and allowing the exhaust of hydraulic fluid from annular space 38 through fluid passageway 48, ports 76 and 77 of four-way valve 42, and through conduit 78 to reservoir 66. Fluid may also exhaust through the pilot valve and conduit 74. The release of this high pressure from annular space 38 allows pump 64 to refill tubular member 18 so that it can again expand, thereby relieving the force on cable 48 so that pilot valve 56 closes pilot fluid opening'58. Hydraulic fluid continues to flow from the annular space 38 until the force exerted on the right end of spool is less than the force exerted by spring 71, so that piston-70 moves back to the right. A small bleed-off line 79 is provided to allow movement of spool 70 all the way to the right. The cycle is then repeated.
It will be appreciated that the unique valving means of this invention, wherein the fluid control valve is made responsive to the movement of the diaphragm, e.g. sleeve 18, allows far more accurate control of the movement of the diaphragm, thereby avoiding the possibility of damage to the diaphragm by excessive flexing, and insuring that maximum volume per stroke, or pulsation, of the pump is obtained.
The embodiment shown in FIGURE 2 also utilizes the principle of controlling the flow of hydraulic fluid in response to the movement of the diaphragm. As shown in this figure, a pump 80 comprises a cylindrical housing 82 fitted with heads 84 and 86. A flexible tubular member 88 is sealingly engaged with bosses on heads 84 and 86, similarly as in the embodiment of FIG- URE 1. However, in this embodiment the inlet 90 to the tubular member is in head 86, and the exhaust 92 is in head 84, so that flow of the pumped fluid is longitudinally through tubular member 88. Check valves 91 and 93 respectively prevent reverse flow in conduits 90 and 92. In this embodiment, tubular member 88 is preferably closely adjacent one interior wall of cylindrical housing 82.
At approximately the longitudinal center of housing 82, a pilot valve housing 94 is affixed. Pilot valve housing 94- is provided with a bore 96 extending substantially perpendicularly of housing 82, and in communication with the space 98 between housing 82 and tubular member 88. The outer end of bore 96 is closed by a plug 180. A hollow cylindrical pilot valve 102 is slidingly and sealingly received in bore 96, and extends therefrom into space 98 and into contact with tubular member 88, a bearing flange 164 being provided on the end of the pilot valve. The pilot valve is biased toward the tubular member by means of a spring 186. An aperture 168 in the wall of the pilot valve and adjacent its lower end provides a passageway for the flow of hydraulic fluid through the passageway. A pilot fluid aperture in the wall of pilot valve housing 94 is positioned to be opened by movement of pilot valve 182 to one position, and to be closed by movement of said pilot valve to another position.
It will be seen that the embodiment of FIGURE 2 operates similarly as that of FIGURE 1. The tubular member 88 is filled with the fluid to be pumped, through inlet 98, this fluid being under a low pressure, so that it causes the tubular member to bulge outwardly, as shown in FIGURE 2. Alternatively, this bulging may be caused by the application of a vacuum on the space )8, through a fluid conduit 112. However, in the preferred embodiment, fluid conduit 112 is used to admit hydraulic fluid under high pressure to space 98, which causes the fluid in the tubular member to be exhausted through fluid conduit 92 at a high pressure. Check valve 93 is preferably in the form of a pressure relief valve, set to open at a pressure somewhat greater than the pressure of the fluid entering the tubular member from conduit 90.
The application of high pressure hydraulic fluid to the space 98, and the consequent reduction of the bulge in tubular member 88, causes pilot valve 102 to move downwardly, under the urging of spring 106, until aperture 118 is opened, whereupon the flow of high pressure fluid therethrough results in the actuation of a four-way 4 valve, as in the embodiment of FIGURE 1. Upward movement of the pilot valve causes reversal of the fourway valve, so as to again allow movement of the high pressure fluid into space 98.
In the embodiment disclosed in FIGURES l and 2, the flow of hydraulic fluid into the space 38 or 98 is initiated as a result of the pressure in the space being decreased to the extent that it can no longer overcome the force of the spring 71 in four-way valve 42, so that the spool 70 is moved. The exhausting of this hydraulic fluid is initiated by the movement of the tubular member 18 or 88, in that such movement opens one of pilot fluid apertures 58 or 110 so that fluid under pressure may cause the four-way valve to open to exhaust.
In another embodiment of the invention, both the admission and the exhaust of hydraulic fluid is directly responsive to the movement of the flexible tubular member. An example of this embodiment is disclosed in FIGURE 3, wherein the four-way valve is solenoid operated.
Thus the tubular member 88 is within a cylindrical housing 82, to which a pilot plunger housing 114 is attached, as in the embodiment of FIGURE 2. A pilot plunger 115 is slidably received in the bore 116 of the pilot plunger housing. The outer end of the bore 116 is closed by a plug 118 which has an axial bore providing a guide for an actuating stem 120 attached to pilot plunger 115. A spring 122 resiliently biases pilot plunger 115 downwardly toward tubular member 88.
Actuatingstem 120 is provided with two spaced-apart fingers 123, 124 which are positioned to operate a single pole, single throw switch 126 upon axial movement of stem 120. Switch 126 is rigidly positioned with respect to pilot plunger housing 114, in that it is aflixed to a bracket 128 which is attached to the pilot plunger housing. Switch 126 is adapted to close a circuit containing a source of electric current 128 and a solenoid 130 which, upon energization, causes longitudinal movement of the spool 132 of fluid control valve 134. Thus when stem 120 is moved to the position shown in FIGURE 3, finger 123 operates switch 126, whereby fluid control valve 134 is actuated to allow flow of hydraulic fluid into the space 98 between tubular member 88 and cylinder housing 82. The pressure of this fluid collapses the flexible tubular member and forces out the pumped fluid, at the same time allowing downward movement of pilot plunger 115 and stem 120, so that finger 124 actuates switch 126 to move the spool 132 of fluid control valve 134 to a position allowing exhaust of the hydraulic fluid from space 98.
A preferred embodiment of this invention is the utilization of a plurality of pumping units as shown in FIG- URES 1, 2, or 3 in parallel, so as to obtain smooth, con tinuous flow of the pumped fluid. One embodiment of such an arrangement is depicted in FIGURE 4, wherein two pumping units having piloting means similar to that shown in FIGURE 1 are used in parallel.
In this embodiment, a first pumping unit has a pumped fluid inlet 152 to which the fluid to be pumped is supplied at low pressure, e.g. 10 to 25 p.s.i.g., by a pump 154. The pumped fluid is exhausted from. pumping unit 150 through outlet 156 and conduit 158. A second pumping unit 160 has a pumped fluid inlet 162 to which fluid to be pumped is supplied at low pressure by pump 154. The pumped fluid is exhausted, at high pressure, from pumping unit 160 through outlet 1'64 and conduit 15%.
The flow of hydraulic fluid to and from pumping units 150 and 160 is controlled by a fluid control valve 166, which in turn is actuated by pilot fluid valve 168 in pumping unit 150, and pilot fluid valve 170 in unit 160.
High pressure hydraulic fluid for operation of both the first and second pumping units is supplied by a pump 172 from reservoir 174. This fluid flows into the first pumping unit through a fluid conduit 176, and into the second pumping unit through a fluid conduit 178. Flow into the first pumping unit causes tubular member 180 therein to collapse and open pilot fluid valve 168, so that pilot fluid flows through pilot fluid conduit 1182 into the right end, as shown in FIGURE 4, of the fluid control valve 166. The pressure of this pilot fluid moves the spool 184 to the left, thus connecting conduit 176 to exhaust conduit 186, so that the hydraulic fluid is exhausted from pumping unit d. At the same time, conduit 173 leading to the second pumping unit 160 is connected to the supply of hydraulic fluid provided by pump 1172, so that tubular member 1% is compressed. When this compression is suflicient to cause the opening of pilot fluid valve 1 7%, pilot fluid flows through conduit 192 to the fluid control valve 166, causing the spool 184 to shift again so that the cycle is repeated. Bleed-otf lines 194 and 1% provide means for relieving the pressure of fluid trapped in the respective ends of the fluid control valve.
it will be appreciated that when a plurality of pumping units are used, the hydraulic fluid supply pump may be allowed to run continuousl alternately supplying hydraulic fluid to first one pumping unit and then other. Ft hen only one pumping unit is operated, the hydraulic fluid pump must be of the type which can operate with closed discharge, or else some means for pressure relief must be provided, as is well known in the art. In addition, when more than one pumping unit is used, continuous, substantially non-pulsating flow of the pumped fluid can be obtained.
The means used for controlling the flow of hydraulic fluid to and from the pumping units of this invention makes possible extremely accurate control of the degree of flexing of the diaphragms of these pumping units, thereby greatly reducing the possibility of over-stressing and rupturing the diaphragm. Simultaneously, since the degree of flexing of the diaphragm is directly related to the rate of flow of the pumped fluid, the valve actuating means of this invention inherently results in the ability to obtain close control over this rate of flow. This is often particularly important in chemical process applications, where the fluids handled require the use of corrosion resistant materials such as can be used in -a diaphragm type pump, and where the accurate proportioning of these fluids fed to chemical processes is extremely critical.
Although several embodiments of this invention have been shown and described herein, the invention is not limited to these specific embodiments, but only as set forth by the following claims.
1. A hydraulic fluid actuated pump comprising an enclosed housing, a tubular diaphragm in said housing dividing the enclosure into an actuating fluid space and a pumped fluid space, conduit means in communication with said pumped fluid space for supplying and exhausting pumped fluid, conduit means in communication with said actuating fluid space for supplying and exhausting actuatin g fluid, whereby said diaphragm is caused to flex and to admit and discharge pumped fluid, a pilot fluid operated fluid control valve in the actuating fluid conduit actuable to control the flow of actuating fluid to and from the actuating fluid space, a pilot fluid valve operably connectcd to said fluid control valve to supply actuating fluid thereto, a flexible non-elastic member in said housing extending longitudinally of said diaphragm and having an end fixed, an intermediate portion attached to said diaphragm, and the other end attached to said pilot valve, and means biasing said pilot valve to a position causing a tension to be imposed on said flexible member and preventing flow of actuating fluid to said fluid control valve.
2. A hydraulic fluid actuated pump comprising a housing; a tubular diaphragm in said housing dividing the space therein into an actuating fluid space and a pumped fluid space; conduit means communicating with said pumped fluid space to supply a fluid to be pumped into said space; conduit means in communication with said pumped fluid space through which pumped fluid may be exhausted therefrom; pump, valve, and conduit means in communication with said actuating fluid space to supply an actuating fluid thereto, whereby said diaphragm is caused to flex in a direction to force pumped fluid from the pumped fluid space; conduit and valve means in communication with said actuating fluid space for releasing actuating fluid therefrom, whereby said diaphragm is caused to flex in a direction to allow entry of pumped fluid into said pumped fluid space; a flexible ring circumscribing said tubular diaphragm intermediate its ends; a substantially non-elastic flexible member extending longitudinally of said tubular diaphragm through said flexible ring; a pilot valve attached to one end of said flexible member, the other end being rigidly fixed; means biasing said pilot valve toward a first position in which a tensile force is applied to said flexible member; and conduit means communicating said pilot valve with the valve means to conduct fluid to the valve means upon flexure of said diaphragm.
3. A diaphragm pump comprising a housing, a tubular diaphragm dividing said housing into a pumped fluid space and an actuating fluid space, conduit means communicating with said pump fluid space for supplying and exhausting pumped fluid, conduit means communicating with said actuating fluid space for supplying and exhausting actuating fluid, pilot fluid operated valve means in said lastnamed conduit means for controlling the flow of actuating fluid to and from said actuating fluid space, a pilot valve attached to said housing, means biasing said pilot valve toward a first position, a substantially non-elastic flexible member attached to said pilot valve and to said diaphragm, whereby flexure of said diaphragm in one direction causes movement of said pilot valve against said biasing means to a second position, a port in said housing positioned to be closed by said pilot valve in said first position and opened by said pilot valve in said second position, and conduit means from said port to said pilot fluid operated valve means.
References Cited in the tile of this patent UNITED STATES PATENTS 2,313,551 Hul'bert Mar. 9, 1943 2,47 8,568 Coe Aug. 9, 1949 2,673,525 Lucas Mar. 30, 1954 2,703,055 Veth et a1. Mar. 1, 1955 2,843,050 Harper July 15, 19 58