US3304126A

US3304126A - Material handling apparatus and methods

Info

Publication number: US3304126A
Application number: US432729A
Authority: US
Inventors: Warren E Rupp; Frank T Sakraida
Original assignee: Gorman Rupp Co
Current assignee: Gorman Rupp Co
Priority date: 1965-02-15
Filing date: 1965-02-15
Publication date: 1967-02-14
Anticipated expiration: 1984-02-14

Description

Feb. 14, 1967 w. E. RUPP ETAL 3,304,126

MATERIAL HANDLING APPARATUS AND METHODS Filed Feb. 15, 1965 5 Sheets-Sheet l Feb, 14, 1967 W. E. RUPP ETAL MATERIAL HANDLING APPARATUS AND METHODS Filed Feb. 15, 1965 5 Sheets-Sheet 2 United States Patent 3,304,126 MATERIAL HANDLING APPARATUS AND METHODS Warren E. Rupp and Frank T. Sakraida, both of Mansfield, Ohio, assignors to The Gonnan-Rupp Company Filed Feb. 15, 1965, Ser. No. 432,729 22 Claims. (Cl. 302-21) This invention relates generally to the art of material handling, and more specifically to apparatus and methods for transporting fiowable materials, including liquids and finely divided solids. The invention is particularly useful in handling pulverulent or particulate materials, such as Fullers earth, flour, powdered sugar or the like, that are capable of being gas-borne and transported through conveying ducts.

The new and improved material handling system which is provided makes it possible to transport fiowable materials faster with less energy and to elevate such materials to a greater height than has been possible with the techniques and apparatus of the prior art. It also overcomes the problems attendant to the handling of materials such as powdered sugar which tend to pack and thereby clog the conduits through which the material is conveyed.

In general, the preferred system comprises the steps of pneumatically pumping the material from a source and controllably introducing a gas into the material stream. The gas may be introduced to fluidize the material being handled and also to purge both the pumping apparatus and the conveying ducts should the material become clogged. The gas which is introduced into a stream of finely divided solids serves to lower the specific gravity of the material and to provide a gaseous conveying medium, whereby the material can be moved with less effort and to many times the height of dry materials which are free of gas. When pumping liquids, the gas may be eflfectively dispersed into the liquid and the liquid prevented from separating from the gas. It has been found that an intermingled liquid and gas stream can be elevated to approximately three times the height of a liquid which is free from gas under the same working pressure. This is due to the fact that the trapped gas bubbles reduce the specific gravity of the liquid. The continued expansion of the gas bubbles which occurs as the liquid stream is progressively elevated further reduces the specific gravity of the combined fluids and results in added irnpetuous to the stream at a constant conveying or working pressure.

In the preferred embodiment of the apparatus contemplated by this invention, there is provided a fluid operated diaphragm pump which includes a plurality of separate pumping chambers and pressure chambers. The intake sides of the pumping chambers may be connected by a manifold to an inlet duct and the outlet sides connected by another manifold to a discharge duct. Flexible diaphragms are interposed between the pressure chambers and pumping chambers. Each of these diaphragms is actuated in opposite directions alternatively to provide an intake or suction stroke for directing material into the associated pumping chamber and a pumping stroke for expelling the material into a discharge manifold or duct. The diaphragms may be connected and controlled in such a manner that one diaphragm moves through a pumping stroke while a connected diaphragm moves through its intake stroke. Since the oscillating diaphragms create a vacuum within the inlet side of the pump, the material to be pumped is picked up without the need of auxiliary feeding equipment.

The diaphragms are preferably actuated by a gas, such as air, under pressure which is selectively admitted into the pressure chambers to affect the pumping strokes and exhausted from the pressure chambers during the intake strokes. The pressure chambers are adapted alternately to be communicated to the discharge manifold during the intake strokes of the diaphragms. The operating medium, after causing the diaphragms to cycle and draw material into the pump, also may be used to fluidize and drive the material through associated discharge conduits by being exhausted into the discharge manifold. Selection of the proper cycling pressure will result in a volume of exhaust gas adequate to convey the material. Since, with certain materials and under some conditions it may not be desirable to introduce gas into the pumped material, the gas exhausted from the pressure chambers may be vented to the atmosphere.

According to one arrangement, the exhaust gas forced from the pressure chamber associated with one diaphragm may be directed into the pumping chamber associated with another diaphragm. This arrangement provides a means of positively forcing heavy materials out of the pump. The system is particularly advantageous when pumping materials, such as powdered sugar, which have a tendency to pack and stick, thereby fouling the material discharge valves of the pumping chambers. When the exhaust gas is alternately forced into each of the pumping chambers on the working sides of the diaphragms, the expansion of the gas adds to the working pressure and effectively blows the material through and away from the discharge valves, thereby preventing their malfunction.

An important feature of the invention is that the operating pressure on the pressure sides of the diaphragms is self-regulating in response to the pressure required to pump the material from the pumping chambers and to keep the material moving through the discharge ducts. In the preferred embodiment of the apparatus, a new and improved, pressure sensitive, directional flow control valve is provided for controlling the pressure in the pressure chambers. This valve may be adjusted so that each pressure chamber is selectively connected to a source of gas under pressure until the pressure in that chamber is sulficient to overcome the normal resistance to movement of the material in the pumping chamber and to cause the diaphragm to move through a pumping stroke. Thereupon, the valve shifts to connect the other pressure chamber to source. In this manner, the pressure sensitive control valve provides for automatic control of the pumping apparatus and prevents excessive pressures from being built up in the pressure chambers on the diaphragms.

The preferred construction of the directional flow contol valve includes magnetic or mechanical detent structure which is adjustable to provide cycling of the valve at any desired pressure. The output pressure from the valve is fed back to the valving member which will shuttle when the set pressure determined by the detent structure is reached. This valve obviates the need for pilot valves or other mechanical means which heretofore have been used to provide the cyling action by direct contact with the diaphragms inside the pump. As mentioned above, the cycling pressure can be selected to suit the pumping conditions. In certain instances, a reduced volume of gas will be required to operate the pump and in other situations an excess of gas may be provided.

In some instances, material may become temporarily clogged in the discharged system, thereby raising the effective Working pressures on the working sides of the diaphragms in the pumping chambers. When this occurs, automatic cycling of the main control valve serves to build up sufilcient pressure in the pressure chambers to balance the excessive pressure in the pumping chambers. Gas under pressure is then admitted into the discharge manifold to free the clogged material and purge the discharge system. Thereupon, the pressure in the pressure chambers is automatically reduced to that normally required to keep the material moving. It will thus be seen that the apparatus provided by this invention is selfcleaning and is capable of pumping materials which could not be handled successfully by pumping apparatus of the prior art.

Since the operating pressure of the preferred apparatus is self-regulating in response to the amount of pressure required to move the material, the pressure differential on each diaphragm is constant in all phases of operation. The diaphragrns essentially act as dividers between two fluids and are merely subjected to compression equal to the operating pressure of the gas in the pressure chambers and the working pressure of the material in the pumping chambers. As a result, the diaphragrns are prevented from being over-stressed and the apparatus is rendered susbtantially maintenance-free.

Other features and a fuller understanding of the invention will be had by reference to the following detailed description and the accompanying drawings.

In the drawings:

FIGURE 1 is a sideelevational view of the preferred diaphragm pump which comprises one aspect of this invention;

FIGURE 2 is a cross-sectional view taken on the line 22 of FIG. 1;

FIGURE 3 is a fragmentary, cross-sectional view taken on the line 3-3 of FIG. 1;

FIGURE 4 is a fragmentary, cross-sectional view taken on the line 44 of FIG. 2;

FIGURE 5 is a fragmentary, cross-sectional view taken on the line 55 of FIG. 1;

FIGURE 6 is an elevational view of the preferred main directional flow control valve;

FIGURE 7 is a diagrammatical, cross-sectional view of the preferred pumping apparatus and the fluid actuating systems therefor;

FIGURE 8 is a fragmentary, cross-sectional view of a modified portion of the apparatus;

FIGURE 9 is a fragmentary, cross-sectional view of still another modified construction; and

FIGURE 10 is a fragmentary, cross-sectional view of still another modified construction.

Referring now to the drawings, and to FIGS. 1-5 in particular, the preferred embodiment of the fluid-operated diaphragm pump of this invention is generally indicated by reference numeral 15. As shown, the pump 15 includes a housing 16 formed by

opposed covers

17, 18 which are secured to a central housing body 19 by bolts 20 and nuts 21. If desired, the pump may be constructed as a mobile unit by mounting the housing 16 on wheels 22. Struts 23 extend down from the housing 16 to support the pump 15 in the operative position illustrated in FIGS. 1 and 2.

A pair of

flexible diaphragrns

28, 29 are mounted within the pump housing 16 to extend across opposite sides of the central housing body 19. The diaphragm 28 is held in place by clamping its marginal edge between an outer radial surface of the housing body 19 and a rim 30 of the cover 17. The diaphragm 29 is similarly secured between a rim 31 of the cover 18 and an outer radial surface of the body 19.

In the illustrated construction, the housing body 19 is formed with a central wall section 33 and with opposed, inwardly dished cavities in its side faces. These cavities are closed by the

diaphragrns

28, 29 to define

pressure chambers

34, 35. The

covers

17, 18 are dished outwardly to form

separate pumping chambers

36, 37 in conjunction with the

diaphragrns

28, 29, respectively. The

chambers

34, 36 are'thus separated by the diaphragm 28 and the

chambers

35, 37 are separated by the diaphragm 29.

As shown most clearly in FIG. 7, each of the

pumping chambers

36, 37 has a material intake port 42 and a material discharge port 43 formed, in the

covers

17, 18. Preferably, the intake ports 42 are elevated above the bottoms of the

pumping chambers

36, 37 so that 9 1% terial drawn into the pumping chambers will drop away from the intake ports. The discharge ports 43 are below the intake ports near the lower portions of the pumping chambers to facilitate the discharge flow of material.

The intake ports 42 may be connected by an intake manifold 44 which is secured to the housing 16 by bolts 45 and nuts 46. The material discharge ports 43 may be connected by a discharge manifold 47 which is also bolted to the housing 16. The discharge manifold 47 has

fiow passages

48, 49 that respectively extend from the pumping

chambers

36, 37. A one-way, material flow control valve 50 is provided in each of the intake ports 42 and the discharge ports 43. The valves 50 are preferably flap-type valves in the form of flat plates, which, in their closed positions, engage against replaceable seats 51. Each of the seats 51 is held in place between two

gaskets

52, 53 by means of the bolts 45 and nuts 46.

Referring again to FIG. 3, the

diaphragrns

28, 29 are movable in unison simultaneously to provide a pumping stroke which expels material through the discharge port 43 of one pumping chamber and an intake or suction stroke which draws material into the other pumping chamber through its intake port 42. The central portion of each diaphragm is clamped between plates '57, 58. Each set of

plates

57, 58 is secured to a reduced diameter end portion of a connecting rod 59 by means of nuts 60 screwed onto threaded portions at the ends of the rods. The diaphragm connecting rod 59 extends through a self-aligning seal ring assembly which includes a floating ring 61. I This ring is loosely mounted within an enlarged center opening 62 of the wall section 33 and is retained in the opening by plates 63 which are secured to opposite sides of the wall section. The plates 63 have aligned openings 64 which are larger than the diameter of the rod 59. The floating ring 61 carries an O-ring 65 which is fitted around the rod 59, and O-rings 66, are provided between the ring 61 and the inner faces of the seal-retaining plates 63. The described floating seal arrangement accommodates radial and angular displacement of the rod 59 and also prevents leakage of gas along the rod between the

pressure chambers

34, 35. In addition, the structure of the floating seal arrangement eliminates the need for bearings and the problem of maintaining lubrication.

Two fluid systems are provided in operative connection with the

diaphragrns

28, 29. The first of these fluid systems comprises the pressure chamber 34 and a communicating passage 67. The passage 67 is formed in the housing body 19 and is ported on an external flat face 68 of the body- The second fluid system comprises the pressure chamber 35 and a communicating passage 69 in the housing body 19 which is also ported on the face 68.

The two fluid systems are adapted tobe energized selectively by a main directional flow control valve assembly 70. This main control valve assembly is mounted externally of the housing .16 to provide quick and easy access to parts of the valve which may require service without the necessity of disassam'bling the basic pump construction. Referring particularly to FIGS. 3, 6 and 7, themain control valve assembly 70 is shown to comprise a valve housing 71 having a flat face 72 which mates against the face 68 of the central housing body 19. The valve housing 71 is formed with a longitudinal bore 73, a pressure port 74, and with spaced flow ports 7578 in the housing face 72. The ends of the bore 73 are closed by end caps 80.

The

flow ports

76 and 77 of the valve assembly 70 respectively communicate with the pressure

chamber connecting passages

67 and 69 in the pump housing body 19. The

flow ports

75 and 78 respectively communicate: with

exhaust passages

81 and 82 which are also cored in the pump housing body 19. The pressure connection: to the main control valve 70 is formed by another pas sage 83 in the member 19 which communicates with the port 74. The pressure passage 83 has an external port 84 and is adapted to be connected to a suitable source (not shown) of gas under pressure by means of a connecting element 85.

A pressure sensitive valve member in the form of a valve spool 90 is longitudinally slidable in the valve housing 71 and is adapted selectively to connect the pressure port 74 with the

flow ports

76, 77. As shown, the spool 90 has four heads which have a fluid-tight running fit in the bore 73 and cooperate with its walls to define spool chambers 91-93 (FIG. 7). In the first operative position of the spool 90 shown in FIG. 7, the pressure port 74 is communicated to the flow port 76 through the spool chamber 92, and the pump housing passage 69 is communicated to the exhaust passage 82 through the flow port 77, the spool chamber 93 and the port 78. When the spool 90 is shifted to the right, as viewed in FIG. 7, to its second operative position, the pressure inlet 74 is communicated to the fio-w port 77 through the spool chamber 92, and the pump housing passage 67 is communicated to the exhaust passage 81 through the flow port 76, the spool chamber 91 and the flow port 75.

The valve spool 90 is operatively disposed between the fluid systems comprising the

pump housing passages

67, 69 so that the spool is movable between its two operative positions in response to a fluid pressure differential in the

pressure chambers

34, 35. The heads adjacent the ends of the spool 90 cooperate with the Walls of the valve housing 71 to define

valve operating chambers

94, 95. These

valve operating chambers

94, 95 are respectively communicated with the

flow ports

76, 77 by channels 96, 97 (FIG. 6). The

channels

96, 97 are shown as being formed in the face 72 of the valve housing 71 and they are closed by the mating face 68 of the pump housing body 19. In the first operative position of the spool 90 shown in FIG. 7, the inlet pressure is transmitted to the valve operating chamber 94 via the flow port 76 and the communicating channel 96. At the same time, the pressure in the pressure chamber 35 is transmitted to the opposite valve actuating chamber 95 via the pump housing passage 69 and the channel 97. The spool 90 will therefore be prevented from shifting to its second operative position until the pressure in the

chambers

34, 94 exceeds the pressure in the

chambers

35, 95. When the spool 90 is in its second operative position, it will not return to the first position until the diaphragm actuating pressure in the

chambers

35, 95 exceeds the exhaust pressure in the

chambers

34, 94.

As contemplated by this invention, the main control valve 70 is provided with detent structure which engages and retains the spool 90 in either of its operative positions until the pressure differential in the

chambers

34, 35 reaches a predetermined level. In the embodiment best illustrated in FIGS. 3 and 7, the valve 70 is made of non-magnetic materials except for

magnetic heads

100, 101 which are provided on the ends of the valve spool 90. Cooperating

permanent magnets

102, 103 are mounted in recesses formed in the valve housing end caps 80 so as to be exposed at the ends of the bore 73. The

magnets

102, 103 are longitudinally movable in the housing 71 toward and away from the

magnetic heads

100, 101 of the spool 90 in order to provide a controlled detent action of the valve spool. This movement may be accomplished by means of screws 104 which are integral with the magnets and are threaded through the end caps 80. The screws are locked in adjusted positions by lock nuts 105.

In FIG. 7, the spool 90 is shown in one of its two operating positions wherein the magnetic head 100 of the spool is at the end of the housing 71 adjacent the magnet 102. The spool 90 will be retained in this position until the pressure in the valve actuating chamber 94 exceeds the pressure in the valve chamber 95 by an amount sufficient to overcome the cooperative detent action of the magnet 102 and the head 100. Thereupon, the spool will shift to the right, as viewed in FIG. 7, to its second operating position wherein the head 101 of the spool is adjacent the magnet 103. The spool 90 will be retained in this second operating position until the pressure in the valve chamber exceeds the pressure in the valve chamber 94 by an amount sufiicient to overcome the detent action of the magnet 103 so as to cause the spool to return to its first position. By adjusting the

magnets

102, 103 toward and away from the magnetic heads of the spool 90, it is possible to increase or decrease the detent action of the magnets and the effective pressure differential in the

chambers

34, 35 which is required to cause the spool to shift.

As generally discussed above, an important feature of this invention is that the operating medium for the pump may be used to fluidize the material being pumped :and to drive it through the connected conduits (not shown).

In the preferred embodiment of the invention, this is accomplished by an arrangement in which the gas alternately exhausted from the pressure chambers 34, '35 may be directed into the

discharge passages

48, 49 of the manifold 47 or into the pumping

chambers

36, 37 in order positively to force the material being handled from the pump and also to purge the apparatus should the material become clogged. To this end, the exhaust passage 81 of the pump housing body 19 may be connected by a conduit (FIG. 5) to a three-position, directional flow control valve 111 which is mounted externally on the manifold 47. This valve maybe a conventional plugtype valve which is operable selectively to communicate the conduit 110 with valve outlet openings 112-114. The outlet opening 112 is vented to the atmosphere, the outlet opening 113 is ported into the discharge passage 48 of the manifold 47, and the outlet opening 114 is communicated to the pumping chamber 37 by a conduit 115. The discharge passage 82 of the pump housing body 19 is similarly connected by a conduit 116 to a plug valve 117 on the manifold 47. The valve 117 is identical to the valve 111 and includes outlet openings 118-120. The outlet opening 118 vents to the atmosphere, the opening 119 is ported into the passage 49 of the manifold 47, and the opening 120 is connected to the pumping chamber 36 by a conduit 121.

In operation of the preferred diaphragm pump 15, the

magnets

102, 103 of the main control valve 70 may be adjusted so that the pressure required to shift the valve spool 90 is slightly greater than the pressure which is required in the

pumping chambers

34, 35 to over-come the resistance of the material to movement and to affect pumping strokes of the

diaphragms

28, 29. For example, if an operating pressure of approximately 4 p.s.i. is required to pump the material from the pumping

chambers

36, 37, the main control valve 70 may be adjusted so that it will shift at a pressure differential of 5 p.s.i. in the

valve actuating chambers

94, 95. Referring to FIG. 7, gas under pressure is admitted into the spool chamber 92 through the presurse passage 83 of the pump housing body 19 and the communicating pressure port 74 of the main control valve 70. With the valve spool 90 in the illustrated position, the gas under pressure is conducted from the spool chamber 92 via the communicating pump housing passage 67 to the pressure chamber 34. The gas under pressure which is directed to the pressure chamber 34 forces the diaphragm 28 to move toward the cover 17 in a pumping stroke. This movement of the diaphragm 28 discharges material from the pumping chamber 36 through the discharge valve 50 into the passage 48 of the discharge manifold 47.

The diaphragm 29 moves with the diaphragm 28 because of the rod 59 which is connected between the two members. Movement of the diaphragm 28 in a pumping stroke causes the connected diaphragm 29 to move in an intake stroke away from the cover 18, thereby drawing material through the intake manifold 44 and the valve 50 in the intake opening 42 into the pumping chamber 37. Thus, the material is picked up without the need of any auxiliary feeding equipment. An the diaphragm 29 moves in its intake stroke, gas is exhausted from the pressure chamber 35 through the passage 69 formed in the pump housing body 19 and the flow port 77 in the main control valve 70 into the spool chamber 93. With the flow control valve 117 set in the position illustrated in FIG. 7, the exhaust gas from the spool chamber 93 is directed through the pump housing passage 82, the conduit 116 and the valve 117 into the passage 49 of the discharge manifold 47. The gas directed into the manifold passage 49 mixes with the material to reduce its specific gravity and add to its velocity. Thus, the material is fluidized so that it can flow readily from the manifold 47 through the connected discharge duct (not shown).

The

diaphragms

28, 29 move through their respective pumping and intake strokes until the diaphragm 28 is adjacent the cover 17 in the broken line position illustrated in FIG. 7. At this point, the clamping plate 58 of the diaphragm 29 contacts an annular stop 125 which is formed on the wall section 33 of the pump housing body 19, thereby preventing further movement of the connected diaphragms. The pressure will therefore build up in the pressure chamber 34 and the communicating pump housing passage 67. Since the

channels

96, 97 formed in the face 72 of the main control valve housing 71 respectively communicate the

pasasges

67, 69 with the

valve actuating chambers

94, 95, it will be seen that the main control valve 70 senses the pressure differential created in the

pressure chambers

34, 35. This pressure differential will increase until it is sufiicient to overcome the detent action of the

magnetic elements

100, 102. Thus, if the main control valve is set to operate at p.s.i. pressure dilferential as assumed above, the spool 90 will shift to the right, as viewed in FIG. 7, away from the magnet 102 when the pressure in the pressure chamber 34 exceeds the pressure in the chamber 35 by five pounds. Due to the increasing attraction of the magnet 103 and the decreasing attraction of the magnet 102, the valve movement will be rapid and positive until the spool 90 contacts the end cap 80 on the right of the housing 71 which acts as a stop for the spool so that it is retained adjacent the magnet 103. This shifting of the valve spool 90 of the main control valve completes the first half cycle of operation.

When the valve spool 90 of the main control valve 70 has been shifted to the right, as viewed in FIG. 7, it will be seen that the pressure port 74 will be connected to the flow port 77 and that both of the

flow ports

75, 76 in the housing 71 will be placed in communication with the spool chamber 91. Thus, the operating gas under pressure is directed into the passage 69 of the pump housing body 19 and into the pressure chamber 35. This causes the diaphragm 29 to move in a pumping stroke toward the cover 18, thereby expelling material from the pumping chamber 37 through the discharge valves50 int-o passage 49 of the manifold 47. The diaphragm 28 moves with the diaphragm 29 to exhaust gas from the pressure chamber 34 through the passage 67 of the pump housing body 19 and the communicating port 76 of the main spool valve 70 into the spool valve chamber 91. The exhaust gas from the spool chamber 91 may be directed through the port 75, the communicating passage 81 of the pump body 19, the conduit 110 and the flow control valve 111 into the passage 48 of the discharge manifold 47. When both diaphragms have moved back to the position illustrated in FIG. 7 so that the clamping plate 58 of the diaphragm 28 contacts a stop 126, the pressure in the diaphragm chamber 35 will build up until the pressure, which is transmitted into the valve actuating chamber 95 via the pump housing passage 69 and the channel 97, is sufficient to overcome the detent force of the magnet 103 and the pressure in the opposite valve chamber 94. The valve will then shift to the position shown in FIG. 7 to complete one cycle of operation.

It will be apparent from the foregoing description that the main control valve 70 functions in response to the difference of pressure in the

pressure chambers

34, 35 and that the pressure created in both chambers is only that which is needed normally to keep the material moving in the discharge manifold 47 and connected ducts. The exhaust gases which are alternately directed into the

passages

48, 49 of the exhaust manifold 47 from each

pressure chamber

34, 35 automatically fluidizes the material being handled in the manner described above.

Asgenerally described above, the operation of the diaphragm pump comprising this invention is such that the pump is self-cleaning and will purge itself in the event that material becomes clogged in the discharge manifold 47 or ducts connected thereto. This self-cleaning effect may be explained by assuming a hypothetical situation in which a material, which normally requires a pumping pressure of 4 p.s.i. to overcome its resistance to movement, becomes clogged, thereby requiring an effective working pressure of 20 p.s.i. in the manifold 47. With the main control valve 70 adjusted to operate at a pressure differential of 5 p.s.i. and in the position illustrated in FIG. 7, a pressure of 5 p.s.i. will be created in the pressure chamber 34 and in the valve actuating chamber 94 through the pressure sensing channel 96. At this point, the valve spool will shift to the right, as viewed in FIG. 7, until a pressure of 10 p.s.i. is created in the pressure chamber 35 and in the valve actuating chamber 95. This alternate increase of pressure in each of the

pressure chambers

34, 35 will continue due to the shuttling of the main control valve'spool 90 until a pressure of 25 p.s.i. exists in the pressure chamber 34 and a pressure of 20 p.s.i. exists in the pressure chamber 35. Neither of the

diaphragms

28, 29 will move in a pumping stroke as the pressure is alternately increased, since there is only a five pound diflierential between the

pressure chambers

34, 35 and since the material requires an effective pumping pressure of 20 p.s.i. before it will move.

Further shuttling of the spool 90 will tend incrementally to build pressures in the

chambers

34, 35 which are in excess of the 20 p.s.i. resistance pressure in the manifold 47 and the

pumping chambers

36, 37. These excess pressures will be alternately transmitted from each pressure chamber to the

manifold passages

48, 49. Thus, when the spool 90 moves to energize the chamber 35 and establish a pressure of 30 p.s.i., the five pound excess pressure differential in the chamber 34 will be transmitted to the discharge passage 48. During the next half cycle of operation, the chamber 34 will be energized to establish a pressure of 3S p.s.i. and the ten pound excess pressure differential in the chamber 35 will be transmitted to the discharge passage 49. This alternate transmittal of excess pressures into the discharge manifold 47 will continue until the pressure in the manifold is 20 p.s.i. At this point, the clogged material will be blown free and the pump will have purged itself.

When the resistance of the material to movement has been thus reduced to that normally required, the pressure in

pressure chambers

34, 35 will drop back to that normally required to move the material.

It will be seen that during this self-cleaning operation, no material will be discharged from either of the

pumping chambers

36, 37, and that no material will be drawn into the chamber so as to add to the already congested condition. Instead, the material is merely compressed on the pumping strokes of the diaphragms and allowed to expand on the intake strokes. It will also be apparent that the diaphragm pump is self-regulating as to the amount of pressure which is required in the pressure chambers relative to the amount of pressure which is required to move the material. Further, at no time is there a greater pressure differential between the two pressure chambers than that which is adjusted by the main flow control valve. Consequently, the diaphragm 9 will not be overstressed even though resistance to movement of the material may become abnormally high.

As generally described above, there are some materials, such as powdered sugar or the like, which tend to pack and stick. Such materials are capable of clogging the

pumping chambers

36, 37 and their discharge valves 50. When pumping such a material, the flow control valves 111, 117 can be adjusted to direct the exhaust gases from the

pressure chambers

34, 35 directly into the pumping

chambers

36, 37. valve 111 can be adjusted to direct exhaust gases from the pressure chamber 34 into the pumping chamber 37. Similarly, the flow control valve 117 can be adjusted to direct exhaust gases from the pressure chamber 35 into the pumping chamber 36. The effect of the exhaust gases when directed into the pumping chambers is substantially the same as that when directed into the manifold 47 except that the gases will blow the materials through and away from the discharge valves to prevent their malfunction.

If desired, the exhaust gases may be merely vented to the atmosphere through the flow control valves 111, 117. In this operation, the gases from the

pressure chambers

34, 35 which are exhausted on the intake strokes of the diaphragms flow through the communicating passages and the flow control valves 111, 117 into the atmosphere without passing into either the discharge manifold 47 or the

pumping chambers

36, 37. This positioning of the flow control valves 111, 117 may be used whenever it is desired to prevent the gases from mingling with the pumped material.

A modified embodiment 70a of the main control valve is shown in FIG. 8. In this modified embodiment, one end of the housing 71a is closed by an end cap 135 and the other end is closed by a wall of a spring detent chamber 136. An extension 137 from the valve spool 90a projects through the end cap 135 and may be used to manually actuate the valve. An opposite end extension 138 projects into the detent chamber 136. Toggle arms 140 engage the end extensions 138 within the detent chamber 136. These toggle arms are adapted to provide a controllable detent action similar to that described in connection with the valve construction 90 and to pass through a dead center position when the spool 90a is shuttled by fluid pressure between its two operative positions. As shown, the arms 140 are loaded by springs 141. These springs are retained between movable washers 142 which engage the ends of the toggle arms and the heads of adjusting screws 143. The screws 143 extend through opposite wall portions of the detent chamber 136 are locked in adjusted positions by nuts 144.

The toggle arms 140' serve to hold the spool 90 in the position illustrated in FIG. 8 until the pressure in the valve actuating chamber 94a overcomes the loading force of the springs 141. The pressure in the chamber 94a then causes the spool to shift to the right, as viewed in FIG. 8, and the toggle arms 140 to pass through a dead center position. The toggle arms will retain the spool in its shifted position until the pressure in the valve chamber 95a overcomes the springs 141, whereupon the spool will again shift to the left and cause the toggle arms to return to the position shown in FIG. 8. Adjustment of the screws 143 will increase or decrease the spring force on the toggle arms 140 and will correspondingly change the pressure differential which is required to shift the valve spool and force the toggle arms through a dead center position.

FIGURES 9 and illustrate modified embodiments of the invention in which the flow control valves 111, 117 and their communicating conduits are eliminated. In the embodiment of FIG. 9, the exhaust flow passage 81 in the pump housing body 19 is communicated directly to the discharge passage 48 of the manifold 47 by a conduit 160. In a similar manner, the exhaust flow passage 82 of the pump housing body 19 is communicated to the For example, the flow control- 1t) passage 49 of the discharge manifold by a conduit 161.

FIGURE 10 illustrates still another embodiment in which the

exhaust flow passages

81, 82 are communicated either directly to the atmosphere or to the

pumping chambers

36, 37. According to this embodiment, a fitting having a blind end 166 and an arm extension 167 is mounted between the manifold 47 and the passage 81 of the pump housing body 19. The arm 167 of the fitting 165 may be connected either to the pumping chamber 37 or vented to the atmosphere. The passage 82 in the body 19 communicates with a similar fitting 170. This member 170 has a blind end 171 and an arm extension 172 which may be vented to the atmosphere or connected to the other pumping chamber 36. It will be understood that operation of the embodiments of both FIGS. 9 and 10 is the same as that discussed above in connection with the embodiment of FIGS. 1-7.

Still other modifications and variations of the invention will be apparent to those skilled in the art in the light of the foregoing detailed disclosure. Therefore, it is to be understood that, within the scope of the appended claims, the invention can be practiced otherwise than as specifically shown and described.

What is claimed is:

1. Pumping apparatus comprising:

(a) housing means,

(b) first and second pumping means in said housing means,

(c) said pumping means cooperating with said housing means to define first and second pumping chambers,

(d) said pumping chambers having intake and discharge openings,

(e) a first fluid system operatively connected to said first pumping means for applying fluid pressure thereto and causing material to be pumped from said first pumping chamber,

(f) a second fluid system operatively connected to said second pumping means for applying fluid pressure thereto and causing material to be pumped from said second pumping chamber, and,

(g) pressure sensitive control valve means for selectively energizing said fluid systems,

(h) said control valve means including a valving member which is operatively disposed between said fluid systems and which is movable between two positions in response to a fluid pressure differential between said systems, said valving member being operable in one position to energize said first fluid system and in another position to energize said second fluid system.

2. The apparatus as claimed in claim 1 wherein said control valve means is accessibly mounted on an external portion of said housing means.

3. Pumping apparatus as claimed in claim 1 including one-way flow valve means for controlling the flow of material through said intake and discharge openings.

4. Pumping apparatus comprising:

(a) housing means,

(b) first and second pumping means in said housing means,

(d) said pumping chambers having intake and discharge openings,

(e) first and second fluid systems respectively connected to said first and second pumping means for applying fluid pressure thereto, each of said systems including a pressure chamber in said housing means and communicating fluid passages, and,

(f) means connected to said fluid passages for selectively energizing said fluid systems, said connected means including means for alternately increasing the pressures in said pressure chambers by a predetermined amount, and means for varying the predetermined amount of alternately increased pressure.

5. Pumping apparatus comprising:

(a) housing means,

(b) first and second pumping means disposed for actuation in said housing means,

(c) said pumping chambers having intake and discharge openings,

(d) diaphragm interposed between said pumping chambers and said pressure chambers,

(c) said housing means and pumping means defining (e) means connecting at least two of said diaphragm first and second pumping chambers, together,

(d) said chambers having intake and discharge open- (f) a first fluid passage connected to a first of said i pressure chambers,

(e) discharge means communicating through said dis- (g) a second fluid passage connected to a second of charge openings with said first and second pumping said pressure chambers, and, h b (11) control valve means for selectively admitting fluid (f) a fi t fl id system operatively t d. t id under pressure into said passages so as alternately to fi t pumping means, pressurize said first and second pressure chambers (g) means forming a first fluid path between said first and h r y cycle S id i phragms through intake fluid system and one of said pumping chambers, 15 and discharge strokes,

(h) a second fluid system operatively connected to said (i) said control valve means including:

second pumping means, (i) a housing having a pressure port, a first flow (i) means forming a second fluid path between said port connected to said first fluid passage, a first second fluid system and the other of said pumping valve chamber communicating with said first chambers, and, fluid passage, a second flow port connected with (j) actuating means for alternately pressurizing and ex said second flow passage, and a second valve hausting said systems to cycle said pumping means chamber communicating with said second flow and thereby draw material into said pumping champ g bers and then force it into said discharge means, said a VaiViIlg m m r reciprocal in Said housing, actuating means being operably connected to said Said Valvillg 11161111351 having axially P P first and second fluid paths and including means for t S sposed in said first and second valve alternately discharging exhaust fluid from said sysc ers so that said member is movable betems into said pumping chambers to act on the m tween two positions in response to a differential terial being pumped. fluid pressure in said valve chambers,

6. A fluid actuated pumping apparatus wherein the opd Va vi g member having a first position erating medium may be used to drive the material bewherein said pressure port is communicated to ing pumped through conveying ducts, said apparatus com- Said first flow port so as to pressurize said first prising; pressure chamber and to said first valve cham- (a) housing means having an intake side and a disand Whafehl Said Second flow P is charge ide, municated to said second valve chamber so as (b) one-way material flow' valves located at the intake t0 @Xeri a biasing force on Said Valving and discharge ide f aid hou i means, ber tending to maintain it in said first position,

(0) supply means communicating with the intake side and said valving member having a second of said housing means, position in which said pressure port is communi- (d) discharge means communicating with the discharge 40 Gated Said Second flow P S0 as P sside of said housing means, surize said second pressure chamber and to said (e) pumping mean disposed for a t ti i id second valve chamber, and wherein said first housing means, said pumping means being actuatable flOW P r is C mImiCatcd to said first valve to create suction at said intake side to draw matechamber as to 674611 a biasing force on d rial into said housing and to force the material into 4.5 Valvhlg member tending to maintain i i Said said discharge means, second position,

(f) means for actuating said pumping means, said ac- Said ValVihg member being movable from Said mating means including; first to said second position when the pressure (i) fluid pressure chambers in said housing means, in said first Valve and Pressure Chambers (ii) a main directional flow control valve for sup- 50 Weds the Pressure in Said Second Valve and P plying an actuating fluid under pressure to said Sure chambers, and from Said ScCOIld 0 a d chambers, said control valve having means refirst P0sition when the Pressllffi in Said 86001161 sponsive to a fluid pressure differential in said Valve and Pressure chambers eXceeds the P h b so as lt t l t pressurize t djfsure in said first valve and pressure chambers. ferent chambers and thereby cycle id pump- 8. The apparatus as claimed in claim 7 including a i means t ff t i t k d di h strokes, floating seal assembly in said housing around said con- (iii) passagemeans connecting said control valve fleeting meansto said chambers within said housing means, said The apparatus as claimed in claim 7 including control valve having a first position in which s e Passages communicating With Said discharge p fl id under pressure i communicated through 1ngs, a fluid connection between said first pressure chamid passage means to one chamber and ber and one of said discharge passages, and a fluid conh d f another chamber and a second nection between said second pressure chamber and ani i i hi h fl id under pressure is other of said discharge passages so that the working fluid i d to i other h b and exhausted supplied to said pressure chambers to cycle said diafrom id one h b phragms can be mixed with the material pumped into (g) and means providing a fluid flow path between sald dlscharge Passagessaid chambers and said discharge means so that the The apparatqs as dimmed in claim 7 including operating fluid can be exhausted from said chambers Charge Valves. assoclated Said discharge openings and and directed into Sai d discharge means to act on the fluid connections between said pressure chambers and said material being pumped. pllmpmg chambers 50 that the Working fluid pp t0 7. Pumping apparatus comprising: saldpressure chambers. to cycle Sald dlaphragms can b6 admitted to sald pumping chambers to act on the mate- (a) housing means, rial therein (b) said housing means having pressure chambers and 11. Pumping apparatus as claimed in claim 7 wherein pumping chambers, said control valve means includes detent means engageable with said valving member to retain it in each of said first and second positions until the difference in pressure between said valve chambers reaches a predetermined level.

12. A pneumatically operated diaphragm pump comprising:

(a) means forming a housing body having cavities in opposite sides thereof,

(b) first and second flexible diaphragms mounted on opposite sides of said body to form first and second pressure chambers,

(c) covers mounted over said diaphragms to form first and second pumping chambers,

(d) said pumping chambers having intake and discharge ports,

(e) means connecting said diaphragms so that they are movable together with one diaphragm moving to effect a pumping stroke while the diaphragm moves to elfect an intake stroke,

(f) structure forming first and second discharge passages respectively communicating with said first and second pumping chambers through said discharge ports,

(g) one-way flow valves mounted in said intake and discharge ports,

(h) first and second fluid systems respectively communicating with said first and second pressure cham bers, and,

(i) actuating means connected between said fluid systems for alternately admitting gas under pressure into each pressure chamber,

(j) said actuating means including a main directional flow control valve having a first valve chamber and a first flow port connected to said first system, a second valve chamber and a second flow port connected to said second system, a pressure port, and a movable valving member extending between said valve chambers, said member being movable in response to a predetermined pressure diflerential in said valve chambers and having a first operative position in which said pressure port is connected to said first flow port and a second operative position in which said pressure port is connected to said second flow port.

13. The apparatus as claimed in claim 12 wherein said main directional flow control valve includes detent means engageable with said valving member to retain it in each operative position until the difference in pressure between said valve chambers reaches a predetermined level.

14. The apparatus as claimed in claim 13 wherein said detent means includes means for varying the effective retaining force on said valving member.

15. The apparatus as claimed in claim 13 including a first fluid connection between said main control valve and said first discharge passage, and a second fluid connection between said main control valve and said second discharge passage, said valving member being effective in its first operative position to connect said second fluid system to said second fluid connection and in its second operative position to connect said first fluid system to said first fluid connection.

16. The apparatus as claimed in claim 13 including first and second directional flow control valves, said first control valve having outlet ports connected to said first discharge passage and to said second pumping chamber, an inlet port connected to said main control valve so that said valving member is operable in its second position to connect said first fluid system to said inlet port, and an operating member operable selectively to connect said inlet port to said outlet ports of said first control valve; and said second control valve having outlet ports connected to said second discharge passage and to said first pumping chamber, an inlet port connected to said main control valve so that said valving member is operable in its first operative position to connect said second fluid to said inlet port of said second control valve, and an operating member operable selectively to connect said inlet port to said outlet ports of said second control valve.

17. In a material handling system including separate pumping chambers, pumping means associated with each chamber and structure forming intake and discharge passages communicating with each chamber, the method comprising alternately applying a gas under pressure to each pumping means, controlling the gas pressure on each pumping means in relation to the resistance to movement of the material from the pumping chambers, and alternately exhausting the gas from each pumping means.

18. The method of claim 17 including the step of directing the exhaust gas into the discharge passages.

19. The method of claim 17 including the step of directing the exhaust gas into the pumping chambers.

20. A method of transporting flowable materials comprising drawing a quantity of material into a first pump ing chamber, pressurizing the material in the first pumping chamber, drawing another quantity of material into a second pumping chamber and pressurizing the material in that chamber, and controlling the application of pressure so that the pressure is alternately applied to the material in each chamber when the pressure on the material in the other chamber is at a predetermined level.

21. In a fluid actuated pumping apparatus including first and second pressure chambers, first and second pumping chambers having intake and discharge openings, and first and second diaphragms interposed between said pressure chambers and pumping chambers for drawing material into said pumping chambers through said intake openings and then discharging the material through said discharge openings, the improvement comprising a system for supplying an operating fluid to said pressure chambers to cycle said diaphragms and exhausting the operating fluid from said pressure chambers into communication with the material being pumped, said system including structure forming a first fluid flow path communicating with said first pressure chamber and with a first portion of said apparatus through which material is moved by actuation of one of said diaphragms, structure forming a second flow path communicating with said second pressure chamber and with a second portion of said second apparatus through which material is moved by another of said diaphragms, and valve means in said first and second flow paths for alternately admitting fluid under pressure to said first pressure chamber while exhausting fluid from said second pressure chamber into said second portion of said apparatus and then admitting fluid under pressure to said second pressure chamber while exhausting fluid from said first pressure chamber into said first portion of said apparatus.

22. Pumping apparatus comprising:

(a) housing means,

(b) said housing means having:

(i) an external surface,

(ii) pressure chambers,

(iii) pumping chambers having intake and discharge openings,

(iv) fiuid passages which communicate with said pressure chambers and which are ported on said external surface,

(c) diaphragms interposed between said pumping chambers and pressure chambers, said diaphragms being actuatable to draw material into said pumping chambers through said intake openings and to discharge material from said pumping chambers through said discharge openings, (d) and a control valve mounted on said external surface of said housing means, (c) said housing means including:

(i) a pressure port, (ii) flow ports communicating with said fluid passages of said housing means,

(iii) and a movable valving member operable in 2,427,703 2/1947 Berkey 103 5 one position to communicate said pressure p011 2,625,886 1/ 1953 Browne 103-152 X with a first of said pressure chambers and in 2,954,737 10/1960 Hoover. another position to communicate said pressure 3,001,306 9/1961 M k 277 173 X port with a second of said pressure chambers. 5 3 1 4 101 1 19 5 Nederynen 3,203,439 8/1965 Beckett 91-318 X Refe'ences C'ted by the Examme 3,218,935 11/1965 York et a1 91-318 UNITED STATES PATENTS 2,307,566 1/ 1943 Browne 103-'152 R BERT M. WALKER, Primary Examiner. 2,342,855 2/ 1944 Green 1035 10 v UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,304,126 February 14, 1967 Warren E Rupp et a1 It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 7, line 3, for "An" read As column 12, lines 3 and S, for "diaphragm", each occurrence, read diaphragms "a Signed and sealed this 17th day of October 1967.

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BREDINER Attesting Officer Commissioner of Patents

Claims

1. PUMPING APPARATUS COMPRISING: (A) HOUSING MEANS, (B) FIRST AND SECOND PUMPING MEANS IN SAID HOUSING MEANS, (C) SAID PUMPING MEANS COOPERATING WITH SAID HOUSING MEANS TO DEFINE FIRST AND SECOND PUMPING CHAMBERS, (D) SAID PUMPING CHAMBERS HAVING INTAKE AND DISCHARGE OPENINGS, (E) A FIRST FLUID SYSTEM OPERATIVELY CONNECTED TO SAID FIRST PUMPING MEANS FOR APPLYING FLUID PRESSURE THERETO AND CAUSING MATERIAL TO BE PUMPED FROM SAID FIRST PUMPING CHAMBER, (F) A SECOND FLUID SYSTEM OPERATIVELY CONNECTED TO SAID SECOND PUMPING MEANS FOR APPLYING FLUID PRESSURE THERETO AND CAUSING MATERIAL TO BE PUMPED FROM SAID SECOND PUMPING CHAMBER, AND,