EP0018143B1 - Air driven diaphragm pump - Google Patents
Air driven diaphragm pump Download PDFInfo
- Publication number
- EP0018143B1 EP0018143B1 EP80301083A EP80301083A EP0018143B1 EP 0018143 B1 EP0018143 B1 EP 0018143B1 EP 80301083 A EP80301083 A EP 80301083A EP 80301083 A EP80301083 A EP 80301083A EP 0018143 B1 EP0018143 B1 EP 0018143B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pump
- inlet
- air
- cavities
- outlet manifolds
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B43/00—Machines, pumps, or pumping installations having flexible working members
- F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
- F04B43/06—Pumps having fluid drive
- F04B43/073—Pumps having fluid drive the actuating fluid being controlled by at least one valve
- F04B43/0736—Pumps having fluid drive the actuating fluid being controlled by at least one valve with two or more pumping chambers in parallel
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L25/00—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means
- F01L25/02—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means by fluid means
- F01L25/04—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means by fluid means by working-fluid of machine or engine, e.g. free-piston machine
- F01L25/06—Arrangements with main and auxiliary valves, at least one of them being fluid-driven
- F01L25/066—Arrangements with main and auxiliary valves, at least one of them being fluid-driven piston or piston-rod being used as auxiliary valve
Definitions
- the present invention is directed to air driven diaphragm pumps.
- Air driven diaphragm pumps have found great utility in construction and industrial uses.
- the durable and reliable nature of these devices along with their ability to handle a wide variety of substances have made these pumps mandatory equipment in many applications.
- the portability of these devices is also a major advantage.
- the least durable part of the pump is most often the diaphragm or diaphragms used to alternately expand and contract the pumping chamber.
- Such diaphragms are expected to survive a high number of flexure cycles and a significant amount of abrasion due to the environment in which they are to operate. These conditions have been found to result in the diaphragms becoming the most frequently replaced components in such pumps.
- Actuator valves for such pumps and other such reciprocating pneumatically driven devices have been developed which employ a pilot valve or rod responsive to the position of the reciprocating element of the device and a pneumatically controlled valve piston responsive to the pilot rod position.
- the valve piston in turn controls the incoming flow of pressurized air to provide an alternating flow to the reciprocating element. This alternating flow forces the element to stroke back and forth thereby performing work and driving the pilot rod.
- Such actuator valves thus convert a relatively steady source of pressurized air into an alternating flow without need for any outside timing or control system.
- the source air pressure alone drives the valve as well as the working device.
- each axial passage on the control rod would vent only one end of the cylinder within which the valve piston operates through movement of the control rod inwardly until the axial passage becomes exposed to a valve piston vent.
- each axial passage must cross the 0-ring seals separating the air cavities of the reciprocating device from the vent passages through the actuator valve housing.
- a pump having opposed pump cavities, a pump drive assembly between said pump cavities forming an inner wall of each of said pump cavities, pump chamber housings meeting with said pump drive assembly to form the outer wall of each of said pump cavities, a respective diaphragm positioned between said pump drive assembly and each said pump chamber housing to divide each said pump cavity into a drive chamber and a pump chamber, an inlet manifold extending to and in communication with each of said pump cavities and an outlet manifold extending to and in communication with each of said pump cavities, said inlet and outlet manifolds being diametrically opposed, characterized by
- each said diaphragm is oriented in a plane parallel to the line of force drawing said inlet and outlet manifolds towards one another and is compressed by drawing said inlet and outlet manifolds towards one another.
- the basic pump configurations can be retained with a central actuator valve, opposed pump cavities with inner and outer pump chamber housings and diametrically positioned inlet and outlet manifolds which extend to each of the opposed pump cavities.
- the use of clamp bands for holding the housings together around the positioned diaphragms and the fasteners required to attach the inlet and outlet manifolds to the pump body are avoided. Instead, mechanisms are employed to forcibly draw the inlet and outlet manifolds towards one another, while the mating surfaces between the inlet and outlet manifolds and the pump chamber housings are at angles such that the drawing force on the inlet and outlet manifolds acts to compress the total assembly together.
- the tie rods may include hand tightened nuts and carriage bolt heads positioned in slots in the diametrically opposed manifolds. Because of the 0-ring type structure of the sealing rim of the diaphragms, it is necessary to create heavy sealing pressure. As pumping pressures within the pump cavities increase, the rims of the diaphragms are forced into greater sealing engagement with the pump housing. Consequently, hand tightening has been found to be sufficient.
- the slotted nature of the manifold attachments makes total unthreading unnecessary for disassembly.
- the carriage bolt heads in association with the slots make holding of the head unnecessary during assembly with the hand tightened nuts.
- the pump incLdes a central pump drive assembly consisting of two drive chamber housings 10 and 12 and an actuator valve 14 positioned between the drive chamber housing 10 and 12. Extending from the actuator valve 14 through the drive chamber housings 10 and 12 is control rod 15. Compressed air is alternately introduced to either side of the pump drive assembly through the actuator valve 14 as determined by the position of the control rod 15.
- the operation of the actuator valve is disclosed in part in US-A-3,017,118, the disclosure of which is incorporated herein by reference.
- Drive chamber housings 10 and 12 abut the sides of the actuator valve 14 with appropriate gaskets 16 and 18 therebetween.
- Circular diaphragms 20 and 22 are associated with the drive chamber housings 10 and 12 to form air chambers 24 and 26.
- Outwardly of the diaphragms 20 and 22 are pump chamber housings 28 and 30 defining pump chambers 29 and 31.
- Piston assemblies are located about the center of each of the diaphragms 20 and 22 and each include an inner plate 32 and an outer plate 34 between which the diaphragms 20 and 22 are sandwiched.
- the inner plate. 32 and outer plate 34 of the piston assemblies is associated with the control rod 15 of the actuator valve 14 as can best be seen in Figure 3.
- the actutor valve 14 provides a source of alternating pressurized air and exhaust to each of the air chambers 24 and 26.
- the diaphragms move as a unit because of the rigid coupling provided by the control rod and piston assemblies.
- the actuator valve 14 supplies pressurized air to one air chamber while exhausting the other air chamber to drive one diaphragm outwardly toward an adjacent pump cavity and to pull the other diaphragm inwardly away from another adjacent pump cavity. In this way, there is an intake stroke in the right pump cavity and a pump stroke on the left pump cavity as the diaphragms move left. At the end of the stroke, the actuator valve reverses the flow and the pump functions are reversed as the diaphragms are forced to move to the right.
- the housing 36 includes two parallel mounting plates 38 and 40 having flat outer surfaces for mating with the drive chamber housings 10 and 12.
- the cross- section of the actuator 14 inwardly of the mounting plates 38 and 40 is best seen in Figure 4.
- Strengthening webs 42, 44 and 46 extend between the mounting plates 38 and 40.
- the air inlet, the valve piston and the means for directing air into and out of the reciprocating device are located in the upper portion of the casting.
- the control rod and bushing Centrally located in the housing 36 is the control rod and bushing.
- the valve piston 48 is positioned in a cylinder 50 formed within the housing 36.
- the valve piston 48 and cylinder 50 cooperates to provide two major functions. The first is to provide means for selectively directing incoming air to either air chamber 24 and 26 and exhausting the opposite chamber in an alternating manner.
- the valve piston 48 and cylinder 50 also cooperate to provide a means for directing incoming air to the ends of the valve piston 48 such that the piston is capable of shifting in response to the position of the reciprocating device.
- the air inlet 52 is directed to the cylinder at a central position spaced from the ends of the cylinder as can best be seen in Figures 4 and 5.
- the valve piston 48 includes an annular groove or channel 54 which cooperates with an arcuate passage 56 cut in the side of the cylinder 50 to direct air to one or the other of two air chamber ducts 58 and 60 as best seen in Figure 3.
- the channel 54 aligned with the air chamber duct 58, incoming air will pass through the air inlet 52, the arcuate passage 56, the channel 54 and into the air chamber duct 58.
- Each of the air chamber ducts 58 and 60 is aligned with a hole through the wall of the drive chamber housings 10 and 12. While air is entering one of the ducts 58 and 60, the other duct will operate as an exhaust passage.
- a cavity 62 exists in the center of the valve piston 48. This cavity enables the air flowing through the exhausting duct to flow through the cavity 62 and through ports 64 and 66 to one of two exhaust ducts 68 and 70.
- the exhaust ducts 68 and 70 extend to a ball check valve 72 as can best be seen in Figure 6.
- valve piston 48 and cylinder 50 The second main function performed by the valve piston 48 and cylinder 50 is the control of the location of the valve piston 48.
- the valve piston 48 has a diameter which is slightly smaller than the diameter of the cylinder 50.
- air is able to flow in the clearance to both ends of the valve piston 48 regardless of its positon in the cylinder 50.
- This clearance is not illustrated in the figures for simplicity.
- the holes 78 and 80 are spaced such that the distance from the inside edge to inside edge is the same as the width of the arcuate passage 56.
- valve piston vent passages 82 and 84 To initiate the shifting of the valve piston 48, one or the other of two valve piston vent passages 82 and 84 is opened to atmosphere. These vent passages are located at the ends of the cylinder 50 as can be seen in Figure 5. During normal operation, the vent passage at the end furthest from the valve piston 48 is vented. The valve piston 48 then moves toward that vented end of the cylinder. During the stroke of the air driven reciprocating device associated with the actuator valve 14, neither end of the cylinder 50 is vented. It is only at each end of the working stroke that venting takes place.
- the cylinder and valve piston tolerance and air passage dimensions are such that the ends of the cylinder 50 may be vented much faster than they are replenished with incoming pressurized air.
- a pressure imbalance is experienced by the valve piston 48.
- the shift chamber at the unvented end of the valve piston 48 has a reservoir of compressed air such that the venting of the other end releases the air spring to drive the valve piston 48 to the vented end of the cylinder.
- the incoming pressurized air also acts to force the valve piston 48 against the opposite side of the cylinder. This is accomplished even during low flow conditions because the ports 64 and 66 are vented. With these areas of lower pressure, a pressure imbalance is created such that the inlet air pressure will hold the piston against the opposite wall.
- This biasing of the piston is beneficial because the axial paths created by the valve piston clearance is more uniform and the valve piston can thus seal the air chamber ducts 58 and 60 and exhaust ducts 68 and 70 where appropriate.
- valve piston is contained within the cylinder 50 by means of the drive chamber housings 10 and 12 which define the ends of the valve piston chamber 50. Furthermore, a pin 90 extending into the bore 76 maintains the angular orientation of the valve piston 48.
- a control rod 15 is used.
- the control rod is fixed to reciprocate with the air driven reciprocating device by either a direct attachment or some conventional form of linkage.
- the control rod is positioned in a passageway through the housing 36.
- the control rod 15 further extends into the air chambers 24 and 26 to retain the diaphragm pistons at a fixed spaced distance from one another and in alignment.
- a bushing 94 fixed to the housing 36 and forming part of the housing provides a guide for the control rod 1 5.
- valve piston vent passages 82 and 84 extend from the ends of the cylinder 50 to circular grooves 96 and 98.
- the valve piston vent passages 82 and 84 cross over as can best be seen in Figure 8.
- Either the valve piston vent passages 82 and 84 or the air chamber ducts 58 and 60 should cross over to opposite ends of the actuator valve 14 so that air flow through the cavity 62 in the valve piston 48 will be toward the end which is abutting the end wall of the cylinder 50.
- On either side of each of the circular grooves 96 and 98 are circular seats which each contain an O-ring seal 100 through 106 to seal these circular grooves 96 and 98.
- the control rod 15 includes an axial passage 110.
- the axial passage 110 includes truncated conical sections with a central cylindrical section having a reduced diameter from the main body of the control rod 15. This axial passage 110 is positioned between the circular grooves 96 and 98 such that when either of the inner O-rings 102 and 104 are encountered, air communication between the valve piston vent passages 82 and 84 and the axial passage 110 is achieved.
- control rod vent passages 112 and 114 extend to atmosphere.
- the control rod vent passages may be in any configuration between the inner seals 102 and 104.
- one continuous passageway may be employed as flow only occurs when the axial passageway moves across one of the seals at 102 or 104.
- the outer seals at 100 and 106 are never disturbed by the axial passage 110. Thus, a constant seal is maintained to prevent any matter from entering into the bushing 94 from the air chambers 24 and 26.
- the operation of the actuator valve is in the nature of a feedback control system. That is, the location of the valve piston 48 determines the movement of the air driven reciprocating device. The movement of the air driven reciprocating device in turn controls the location of the control rod 15. The control rod location determines the position of the valve piston.
- the control of the stroke of the air driven reciprocating device is the width of the axial passage 110 and the distance between the seals at the O-rings 102 and 104. Roughly, the distance between the seals 102 and 104 minus the length of the axial passage 110 equals the stroke length of the reciprocating device.
- the drive chamber housings 10 and 12 are associated with pump chamber housing 28 and 30 to form opposed pump cavities. These cavities are most conveniently circular and are of sufficient depth to accommodate the full stroke of the pump.
- the diaphragms 20 and 22 divide each of the opposed pump cavities into air chambers 24 and 26 and pump chambers 29 and 31.
- the diaphragms 20 and 22 have a circular bead about the periphery of the diaphragm.
- Each bead 116 is positioned in two channels, one in the drive chamber housings 10 and 12 and one in the pump chamber housing 28 and 30. The bead acts to seal the chambers and to locate the housings relative to one another.
- the combination of the piston assemblies and the control rod 15 maintain the alignment of the diaphragm, contribute to uniform flexure and provide a feedback input to the actuator valve 14.
- the pump chamber housing 28 and 30 define the outer walls of the opposed pump cavities forming pump chambers with the diaphragms 20 and 22.
- Each pump chamber housing 28 and 30 includes an inlet port 118 and an outlet port 120.
- the inlet port 118 is located at the lower end of the pump chamber housing and includes a ball check valve located therein.
- the ball check valve includes a ball 122, a seat 124 and ribs 126.
- the ribs 126 simply act to retain the ball 122 in the ball check valve.
- the seat 124 is conveniently positioned at the outer end of the inlet port 118 so that it can be easily replaced if necessary.
- the inlet port 118 terminates in a surface which is in a plane at roughly at 45° angle to the axis of the control rod 15.
- the outlet port 120 is simply a hole through the wall of the pump chamber housings 28 and 30 which terminates in a surface which is also at an angle relative to the control rod 15 of approximately 45°.
- the inlet manifold 128 extends from a central inlet 130 outwardly to the inlet ports 118 associated with each pump chamber housing 28 and 30.
- the inlet manifold 128 conveniently includes feet 132 in order that the pump will stand independently.
- An inlet passageway 134 extends from the inlet 130 to each of the inlet ports 118 such that a mating surface is provided adjacent each of the inlet ports 118 which will meet the surface extending at 45° relative to the control rod 15, the inlet manifold 128 being outwardly, with respect to said pump drive assembly of the inlet ports 118.
- the valve seat 124 is positioned at the surface of each of the inlet ports 118 to hold the seat 124 in place by placement of the inlet manifold 128 as can best be seen in Figure 1.
- An outlet manifold 136 is positioned above the main part of the pump and is diametrically opposed to the inlet manifold 128.
- the outlet manifold 136 also includes a central port 138 and a passageway 140 extending to each of the pump chamber housings 28 and 30.
- the outlet manifold 136 includes outlet port ball check valves each including a ball 142, a seat 144 and placement ribs 146. The ball check valve is placed in the outlet manifold rather than in the pump chamber housings 28 and 30 such that the seat 144 may be at the joint between the pump chamber housings 28 and 30 and the outlet manifold 136 as can best be seen in Figure 1.
- each of the pump chamber housings 28 and 30 mating with the outlet manifold 136 is angled, as mentioned above, at 45°.
- the mating surfaces of the outlet manifold 136 are similarly angled such that the outlet manifold is outwardly, with respect to said pump drive assembly, of the pump chamber housings 28 and 30.
- tie rods 148 extend between the inlet manifold 128 and the outlet manifold 136. As can be seen in Figure 2, a pair of tie rods are positioned at one end of the pump. As can be seen in Figure 1, a second pair of tie rods 148 is positioned at the other end of the pump as well.
- the tie rods 148 include carriage bolts 150 threaded at one end to receive hand tightened nuts 152. These tie rods 148 act as means for forcibly drawing the inlet manifold 128 and the outlet manifold 136 together and provide a drawing line of force along the rods.
- the manifold 128 and 136 have open ended slots 154 for receiving the tie rods 148 without completely separating the nut 152 from the bolt 150.
- the mating surfaces between both manifolds and the pump chamber housings 28 and 30 are at acute angles relative to the direction of force imposed by the tie rods 148.
- the manifolds 128 and 136 are drawn together. This movement in turn forces the pump chamber housings 28 and 30 toward one another. Compression in the main body of the pump is then experienced to hold the diaphragms 20 and 22 between the drive chamber housings 10 and 12 and the pump chamber housings 28 and 30.
- the drive chamber housings 10 and 12 may also be retained in this compressed assembly against the actuator valve 14.
- four tie rods 148 are capable of holding the entire pump assembly together.
- the angle of the mating surfaces to the tie rods is shown to be 45°. However, a 45° angle is not critical and may be increased or decreased depending on the amount of compression per unit of tension in the tie rods which may be desired.
- an improved air driven diaphragm pump assembly which is easy to assemble and which employs a minimum of parts. Consequently, diaphragms, check valves and the valve actuator may be changed very quickly with a minimum of down time and a minimum of potential assembly error.
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- Reciprocating Pumps (AREA)
Description
- The present invention is directed to air driven diaphragm pumps.
- Air driven diaphragm pumps have found great utility in construction and industrial uses. The durable and reliable nature of these devices along with their ability to handle a wide variety of substances have made these pumps mandatory equipment in many applications. In many constructions and maintenance operations, the portability of these devices is also a major advantage.
- In pumps of this nature, the least durable part of the pump is most often the diaphragm or diaphragms used to alternately expand and contract the pumping chamber. Such diaphragms are expected to survive a high number of flexure cycles and a significant amount of abrasion due to the environment in which they are to operate. These conditions have been found to result in the diaphragms becoming the most frequently replaced components in such pumps.
- In spite of the need to periodically replace diaphragms in such devices, the diaphragms are located by necessity in positions where the major portion of the pump must be disassembled to effect their replacement. The outer pump cavity housings must naturally be removed. Furthermore, the inlet and outlet manifolding associated with those outer housings also must be detached. Heretofore, clamp bands have been employed to hold the diaphragm chamber housings together; and separate attachment mechanisms have been used to secure the manifolds. To provide repeated easy access to the diaphragm, a substantial number of bolts, clamp bands and associated fasteners have been required. Naturally, with each additional component, the pump gains in weight, cost and complexity. At the same time, the difficulty of disassembly and reassembly increases the possibility of error becomes greater. Thus, it has long been a goal of the pump manufacturers to reduce the number of components and potential trouble spots associated with such pumps.
- The foregoing difficulty is greatly aggravated in certain industries and uses where frequent dismantling is required. In brewing, all system components handling yeast or mixtures containing yeast, including pumps, must be broken down daily for cleaning. In pumping certain substances, it may also be necessary to frequently clean the pump chambers to prevent product build up and the like. Therefore, there are many situations where the pumps must be disassembled far more frequently than would be required to replace a diaphragm which has failed. Naturally, the possibilities for error are greatly increased with such frequent dismantling.
- Actuator valves for such pumps and other such reciprocating pneumatically driven devices have been developed which employ a pilot valve or rod responsive to the position of the reciprocating element of the device and a pneumatically controlled valve piston responsive to the pilot rod position. The valve piston in turn controls the incoming flow of pressurized air to provide an alternating flow to the reciprocating element. This alternating flow forces the element to stroke back and forth thereby performing work and driving the pilot rod. Such actuator valves thus convert a relatively steady source of pressurized air into an alternating flow without need for any outside timing or control system. The source air pressure alone drives the valve as well as the working device.
- One such actuator valve used primarily on air driven diaphragm pumps is disclosed in US-A-3,071,118, the disclosure of which is incorporated herein by reference. This pump system has included air driven diaphragms positioned on either side of an actuator valve in an arrangement substantially identical, outwardly of the actuator valve and pilot or control rod, to the pump shown in Figure 1 herein. In the earlier actuator valves employed with these pumps, the valve piston has been oriented vertically and the pilot rod has included two axial passages for selectively venting the appropriate ends of the chamber within which the valve piston is to operate. Vents for the axial passages have been positioned outwardly of the valve piston vents along the passageway through which the control rod extends. In this way each axial passage on the control rod would vent only one end of the cylinder within which the valve piston operates through movement of the control rod inwardly until the axial passage becomes exposed to a valve piston vent. Thus, each axial passage must cross the 0-ring seals separating the air cavities of the reciprocating device from the vent passages through the actuator valve housing.
- It is an object of the present invention to provide an improved structure for an air driven diaphragm pump.
- According to the invention there is provided a pump having opposed pump cavities, a pump drive assembly between said pump cavities forming an inner wall of each of said pump cavities, pump chamber housings meeting with said pump drive assembly to form the outer wall of each of said pump cavities, a respective diaphragm positioned between said pump drive assembly and each said pump chamber housing to divide each said pump cavity into a drive chamber and a pump chamber, an inlet manifold extending to and in communication with each of said pump cavities and an outlet manifold extending to and in communication with each of said pump cavities, said inlet and outlet manifolds being diametrically opposed, characterized by
- means for forcibly drawing said inlet and outlet manifolds towards one another;
- said inlet and outlet manifolds and said pump chamber housing including mating surfaces therebetween lying in planes at an acute angle to the line of force drawing said inlet and outlet manifolds towards one another, said inlet and outlet manifold mating surfaces each being outwardly, with respect to said pump drive assembly, of each associated pump chamber housing mating surface.
- Preferably each said diaphragm is oriented in a plane parallel to the line of force drawing said inlet and outlet manifolds towards one another and is compressed by drawing said inlet and outlet manifolds towards one another.
- The basic pump configurations can be retained with a central actuator valve, opposed pump cavities with inner and outer pump chamber housings and diametrically positioned inlet and outlet manifolds which extend to each of the opposed pump cavities. The use of clamp bands for holding the housings together around the positioned diaphragms and the fasteners required to attach the inlet and outlet manifolds to the pump body are avoided. Instead, mechanisms are employed to forcibly draw the inlet and outlet manifolds towards one another, while the mating surfaces between the inlet and outlet manifolds and the pump chamber housings are at angles such that the drawing force on the inlet and outlet manifolds acts to compress the total assembly together. In this way, simple tie rods between the inlet and outlet manifolds may act to hold all of the pump components in place. Thus weight, complexity and the chance of errors in disassembly and reassembly all are reduced. All of these effects are very advantageous to the utility of such devices.
- The tie rods may include hand tightened nuts and carriage bolt heads positioned in slots in the diametrically opposed manifolds. Because of the 0-ring type structure of the sealing rim of the diaphragms, it is necessary to create heavy sealing pressure. As pumping pressures within the pump cavities increase, the rims of the diaphragms are forced into greater sealing engagement with the pump housing. Consequently, hand tightening has been found to be sufficient. The slotted nature of the manifold attachments makes total unthreading unnecessary for disassembly. The carriage bolt heads in association with the slots make holding of the head unnecessary during assembly with the hand tightened nuts.
- By way of example an embodiment of the invention will now be described with reference to the accompanying drawings, of which:
- Figure 1 is an elevation of a pump of the present invention with portions cut away from clarity.
- Figure 2 is a side view of the pump of Figure 1.
- Figure 3 is a cross-sectional elevation of an actuator valve shown in assembly with the diaphragms of the air driven diaphragm pump of Figure 1.
- Figure 4 is a cross-sectional view taken along line 4-4 of Figure 3.
- Figure 5 is a cross-sectional view taken along line 5-5 of Figure 4.
- Figure 6 is a cross-sectional view taken along lines 6-6 of Figure 4.
- Figure 7 is a cross-sectional view taken along lines 7-7 of Figure 5.
- Figure 8 is a cross-sectional view taken along line 8-8 of Figure 7 with a portion of the control rod bushing broken out for clarity.
- Turning in detail to the drawings, an air driven diaphragm pump is illustrated. The pump incLdes a central pump drive assembly consisting of two
drive chamber housings actuator valve 14 positioned between thedrive chamber housing actuator valve 14 through thedrive chamber housings control rod 15. Compressed air is alternately introduced to either side of the pump drive assembly through theactuator valve 14 as determined by the position of thecontrol rod 15. The operation of the actuator valve is disclosed in part in US-A-3,017,118, the disclosure of which is incorporated herein by reference. - An overview of the operation and elements of the pump may be best viewed from Fig. 1.
Drive chamber housings actuator valve 14 withappropriate gaskets Circular diaphragms drive chamber housings air chambers diaphragms pump chamber housings pump chambers diaphragms inner plate 32 and anouter plate 34 between which thediaphragms outer plate 34 of the piston assemblies is associated with thecontrol rod 15 of theactuator valve 14 as can best be seen in Figure 3. - In the context of the air driven diaphragm pump illustrated in Figure 3, the
actutor valve 14 provides a source of alternating pressurized air and exhaust to each of theair chambers actuator valve 14 supplies pressurized air to one air chamber while exhausting the other air chamber to drive one diaphragm outwardly toward an adjacent pump cavity and to pull the other diaphragm inwardly away from another adjacent pump cavity. In this way, there is an intake stroke in the right pump cavity and a pump stroke on the left pump cavity as the diaphragms move left. At the end of the stroke, the actuator valve reverses the flow and the pump functions are reversed as the diaphragms are forced to move to the right. - Looking specifically to the
actuator valve 14, a unitary casting is employed in the preferred embodiment ashousing 36. Thehousing 36 includes twoparallel mounting plates drive chamber housings actuator 14 inwardly of the mountingplates webs plates housing 36 is the control rod and bushing. - The
valve piston 48 is positioned in acylinder 50 formed within thehousing 36. Thevalve piston 48 andcylinder 50 cooperates to provide two major functions. The first is to provide means for selectively directing incoming air to eitherair chamber valve piston 48 andcylinder 50 also cooperate to provide a means for directing incoming air to the ends of thevalve piston 48 such that the piston is capable of shifting in response to the position of the reciprocating device. To accomplish these functions, theair inlet 52 is directed to the cylinder at a central position spaced from the ends of the cylinder as can best be seen in Figures 4 and 5. - In providing a means for charging and exhausting the air chambers of the reciprocating device, the
valve piston 48 includes an annular groove orchannel 54 which cooperates with anarcuate passage 56 cut in the side of thecylinder 50 to direct air to one or the other of twoair chamber ducts 58 and 60 as best seen in Figure 3. With thechannel 54 aligned with theair chamber duct 58, incoming air will pass through theair inlet 52, thearcuate passage 56, thechannel 54 and into theair chamber duct 58. Each of theair chamber ducts 58 and 60 is aligned with a hole through the wall of thedrive chamber housings ducts 58 and 60, the other duct will operate as an exhaust passage. Acavity 62 exists in the center of thevalve piston 48. This cavity enables the air flowing through the exhausting duct to flow through thecavity 62 and throughports 64 and 66 to one of two exhaust ducts 68 and 70. The exhaust ducts 68 and 70 extend to aball check valve 72 as can best be seen in Figure 6. When thevalve piston 48 is shifted from one end to the other of thecylinder 50, the flow through theair chamber ducts 58 and 60, thecavity 62 and theports 64 and 66 is reversed. The shift in thevalve piston 48 also causes one of the exhaust ducts 68 and 70 to become blocked off while the other is opened for exhausting the alternate one of theair chambers - The second main function performed by the
valve piston 48 andcylinder 50 is the control of the location of thevalve piston 48. To this end, thevalve piston 48 has a diameter which is slightly smaller than the diameter of thecylinder 50. Thus, air is able to flow in the clearance to both ends of thevalve piston 48 regardless of its positon in thecylinder 50. This clearance is not illustrated in the figures for simplicity. There are also two axial paths allowing a greater amount of air to selectively flow to one end of the other of thevalve piston 48. These axial paths each include abore 74 and 76 and ahole 78 and 80 drilled into the respective bore. Theholes 78 and 80 are spaced such that the distance from the inside edge to inside edge is the same as the width of thearcuate passage 56. Thus, only one of theholes 78 and 80 may be exposed directly to the incoming air in thearcuate passage 56 at one time. This selective direction of air through theholes 78 and 80 provides an effective anti-stall feature better described in the earlier patent US-A-3,071,118. - To initiate the shifting of the
valve piston 48, one or the other of two valvepiston vent passages cylinder 50 as can be seen in Figure 5. During normal operation, the vent passage at the end furthest from thevalve piston 48 is vented. Thevalve piston 48 then moves toward that vented end of the cylinder. During the stroke of the air driven reciprocating device associated with theactuator valve 14, neither end of thecylinder 50 is vented. It is only at each end of the working stroke that venting takes place. - During the working stroke of the air driven reciprocating device, air flows through the clearance between the
valve piston 48 and thecylinder 50 and through one of the paths in thevalve piston 48. Once pressure has built up at both ends, there is substantially no flow axially in thecylinder 50. Twobosses 86 and 88 form spacers on either end of thevalve piston 48 such that an annular air space is created at the ends of thevalve piston 48. This air space has been referred to as a shift chamber and acts as a potential energy storage mechanism to effect the shifting of thevalve piston 48. - The cylinder and valve piston tolerance and air passage dimensions are such that the ends of the
cylinder 50 may be vented much faster than they are replenished with incoming pressurized air. Thus, when venting occurs at one end of thevalve piston chamber 50, a pressure imbalance is experienced by thevalve piston 48. The shift chamber at the unvented end of thevalve piston 48 has a reservoir of compressed air such that the venting of the other end releases the air spring to drive thevalve piston 48 to the vented end of the cylinder. Once thevalve piston 48 reaches just past half way in its shift through thecylinder 50, the shifting is aided by the axial path of thevalve piston 48 extending to the unvented end of thecylinder 50. This mechanism insures a complete shift. - The incoming pressurized air also acts to force the
valve piston 48 against the opposite side of the cylinder. This is accomplished even during low flow conditions because theports 64 and 66 are vented. With these areas of lower pressure, a pressure imbalance is created such that the inlet air pressure will hold the piston against the opposite wall. This biasing of the piston is beneficial because the axial paths created by the valve piston clearance is more uniform and the valve piston can thus seal theair chamber ducts 58 and 60 and exhaust ducts 68 and 70 where appropriate. - The valve piston is contained within the
cylinder 50 by means of thedrive chamber housings valve piston chamber 50. Furthermore, apin 90 extending into thebore 76 maintains the angular orientation of thevalve piston 48. - To achieve the shifting of the
valve piston 48 at the appropriate time, acontrol rod 15 is used. The control rod is fixed to reciprocate with the air driven reciprocating device by either a direct attachment or some conventional form of linkage. The control rod is positioned in a passageway through thehousing 36. Thecontrol rod 15 further extends into theair chambers bushing 94 fixed to thehousing 36 and forming part of the housing provides a guide for the control rod 1 5. - The valve
piston vent passages cylinder 50 tocircular grooves piston vent passages piston vent passages air chamber ducts 58 and 60 should cross over to opposite ends of theactuator valve 14 so that air flow through thecavity 62 in thevalve piston 48 will be toward the end which is abutting the end wall of thecylinder 50. On either side of each of thecircular grooves ring seal 100 through 106 to seal thesecircular grooves - The
control rod 15 includes anaxial passage 110. Theaxial passage 110 includes truncated conical sections with a central cylindrical section having a reduced diameter from the main body of thecontrol rod 15. Thisaxial passage 110 is positioned between thecircular grooves rings piston vent passages axial passage 110 is achieved. - Between the inner O-
rings rod vent passages inner seals axial passage 110. Thus, a constant seal is maintained to prevent any matter from entering into thebushing 94 from theair chambers - Through the use of the single
axial passage 110, there is no direct blow-by where pressurized air is lost through open seals. Thus, the air actually needed to fill theair chambers diaphragms valve piston 48 is substantially all that is used by the present device. - In overview, the operation of the actuator valve is in the nature of a feedback control system. That is, the location of the
valve piston 48 determines the movement of the air driven reciprocating device. The movement of the air driven reciprocating device in turn controls the location of thecontrol rod 15. The control rod location determines the position of the valve piston. The control of the stroke of the air driven reciprocating device is the width of theaxial passage 110 and the distance between the seals at the O-rings seals axial passage 110 equals the stroke length of the reciprocating device. - Looking in greater detail to the pump itself, the
drive chamber housings pump chamber housing diaphragms air chambers pump chambers diaphragms bead 116 is positioned in two channels, one in thedrive chamber housings pump chamber housing control rod 15 maintain the alignment of the diaphragm, contribute to uniform flexure and provide a feedback input to theactuator valve 14. - The
pump chamber housing diaphragms pump chamber housing inlet port 118 and an outlet port 120. Theinlet port 118 is located at the lower end of the pump chamber housing and includes a ball check valve located therein. The ball check valve includes aball 122, a seat 124 andribs 126. Theribs 126 simply act to retain theball 122 in the ball check valve. The seat 124 is conveniently positioned at the outer end of theinlet port 118 so that it can be easily replaced if necessary. Theinlet port 118 terminates in a surface which is in a plane at roughly at 45° angle to the axis of thecontrol rod 15. The outlet port 120 is simply a hole through the wall of thepump chamber housings control rod 15 of approximately 45°. - The
inlet manifold 128 extends from acentral inlet 130 outwardly to theinlet ports 118 associated with eachpump chamber housing inlet manifold 128 conveniently includesfeet 132 in order that the pump will stand independently. Aninlet passageway 134 extends from theinlet 130 to each of theinlet ports 118 such that a mating surface is provided adjacent each of theinlet ports 118 which will meet the surface extending at 45° relative to thecontrol rod 15, theinlet manifold 128 being outwardly, with respect to said pump drive assembly of theinlet ports 118. The valve seat 124 is positioned at the surface of each of theinlet ports 118 to hold the seat 124 in place by placement of theinlet manifold 128 as can best be seen in Figure 1. - An
outlet manifold 136 is positioned above the main part of the pump and is diametrically opposed to theinlet manifold 128. Theoutlet manifold 136 also includes acentral port 138 and apassageway 140 extending to each of thepump chamber housings outlet manifold 136 includes outlet port ball check valves each including aball 142, a seat 144 andplacement ribs 146. The ball check valve is placed in the outlet manifold rather than in thepump chamber housings pump chamber housings outlet manifold 136 as can best be seen in Figure 1. The surface of each of thepump chamber housings outlet manifold 136 is angled, as mentioned above, at 45°. The mating surfaces of theoutlet manifold 136 are similarly angled such that the outlet manifold is outwardly, with respect to said pump drive assembly, of thepump chamber housings - To tie the pump assembly together,
tie rods 148 extend between theinlet manifold 128 and theoutlet manifold 136. As can be seen in Figure 2, a pair of tie rods are positioned at one end of the pump. As can be seen in Figure 1, a second pair oftie rods 148 is positioned at the other end of the pump as well. In the present embodiment, thetie rods 148 includecarriage bolts 150 threaded at one end to receive hand tightened nuts 152. Thesetie rods 148 act as means for forcibly drawing theinlet manifold 128 and theoutlet manifold 136 together and provide a drawing line of force along the rods. The manifold 128 and 136 have open endedslots 154 for receiving thetie rods 148 without completely separating thenut 152 from thebolt 150. - As can be seen in Figure 1, the mating surfaces between both manifolds and the
pump chamber housings tie rods 148. As the tie rods are drawn together, themanifolds pump chamber housings diaphragms drive chamber housings pump chamber housings drive chamber housings actuator valve 14. In this way fourtie rods 148 are capable of holding the entire pump assembly together. The angle of the mating surfaces to the tie rods is shown to be 45°. However, a 45° angle is not critical and may be increased or decreased depending on the amount of compression per unit of tension in the tie rods which may be desired. - Thus, an improved air driven diaphragm pump assembly is disclosed which is easy to assemble and which employs a minimum of parts. Consequently, diaphragms, check valves and the valve actuator may be changed very quickly with a minimum of down time and a minimum of potential assembly error.
Claims (5)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US29619 | 1979-04-13 | ||
US06/029,619 US4247264A (en) | 1979-04-13 | 1979-04-13 | Air driven diaphragm pump |
US06/038,685 US4242941A (en) | 1979-05-14 | 1979-05-14 | Actuator valve |
US38685 | 1979-05-14 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0018143A1 EP0018143A1 (en) | 1980-10-29 |
EP0018143B1 true EP0018143B1 (en) | 1984-01-18 |
Family
ID=26705152
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP80301083A Expired EP0018143B1 (en) | 1979-04-13 | 1980-04-03 | Air driven diaphragm pump |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0018143B1 (en) |
AU (1) | AU540381B2 (en) |
BR (1) | BR8002292A (en) |
DE (1) | DE3066127D1 (en) |
MX (1) | MX151052A (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3261533D1 (en) * | 1981-06-06 | 1985-01-24 | Selwood Ltd William R | A pump |
DE3206242A1 (en) * | 1982-02-20 | 1983-09-22 | Rudolf 4670 Lünen Leinkenjost | Double chamber diaphragm pump |
JP4330323B2 (en) | 2001-10-24 | 2009-09-16 | 株式会社タクミナ | Reciprocating pump |
DE60327117D1 (en) * | 2002-10-09 | 2009-05-20 | Tacmina Corp | Displacement pump with two diaphragms |
CN108087235B (en) * | 2018-01-18 | 2023-09-01 | 浙江想能睡眠科技股份有限公司 | Air pump control device of mattress with intelligent control of softness and hardness |
CN114922801B (en) * | 2022-04-27 | 2023-11-28 | 上海侠飞泵业有限公司 | High-pressure pneumatic diaphragm pump |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB191111068A (en) * | 1911-05-08 | 1912-03-28 | Wilhelm Goert Boonzaier | An Improved Combination Single- and Double-action (Vertical or Horizontal) Reversible One-cylinder Pump for Raising Water and for other purposes. |
US2625886A (en) * | 1947-08-21 | 1953-01-20 | American Brake Shoe Co | Pump |
GB1379594A (en) * | 1971-05-25 | 1975-01-02 | Morrison Pumps Ltd | Hydraulically actuated diaphragm pumps |
US4019838A (en) * | 1975-09-03 | 1977-04-26 | Fluck Henry T | Air pressure-actuated double-acting diaphragm pump with means to produce a selected start-up position |
-
1980
- 1980-04-03 DE DE8080301083T patent/DE3066127D1/en not_active Expired
- 1980-04-03 EP EP80301083A patent/EP0018143B1/en not_active Expired
- 1980-04-10 AU AU57344/80A patent/AU540381B2/en not_active Ceased
- 1980-04-11 MX MX181947A patent/MX151052A/en unknown
- 1980-04-11 BR BR8002292A patent/BR8002292A/en unknown
Also Published As
Publication number | Publication date |
---|---|
AU540381B2 (en) | 1984-11-15 |
AU5734480A (en) | 1980-10-16 |
MX151052A (en) | 1984-09-18 |
DE3066127D1 (en) | 1984-02-23 |
EP0018143A1 (en) | 1980-10-29 |
BR8002292A (en) | 1980-12-02 |
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