US1525434A - Pneumatic displacement pump - Google Patents

Description

B. S. AIKMAN PNEUMATIC DISPLACEMENT PUMP Filed Oct. 29, 1921 4 Sheets-Sheet 1 hwmldr Feb. :10, 1925,

B. s. AIKMAN 25,434

PNEUMAT I C DI SPLACEMENT PUMP RESERVOI CDNTFOL 5 VlL/II/lllllllll l VIlII/I/ Mala m Feb. 10, 1925.

QWL W5 B. S. AIKMAN PNEUMATIC DISPLACEMENT rum? Filed 001%. 29, 1921 @a gufllllllllllllllli 4 Sheets-Sheet 4 nu k Patented Feb. 10, 1925.

UNITED STATES- PATENT OFFICE.

BURTON S. AIKMAN, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO NATIONAL BRAKE & ELECTRIC COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WIS- CONSIN.

PNEUIVIATIC DISPLACEMENT PUMP.

Application filed October 29, 1921. Serial No. 511,518.

To all whom it may concem: I 7

Be it known that I, BURTON S/AIKMAN, a citizen of the United States, residing at Milwaukee, in' the county of Milwaukee and State of Wisconsin, have invented a certain new and useful Improvement in Pneumatic Displacement Pumps (Case 43), of which the following is a'full, clear, concise, and exact description, reference being had to the accompanying drawings forming apart of this specification.

My invention relates to pneumatic displacement pumps, particularly of the type adapted for faucet control.- While I shall describe and illustrate the invention in connection with a closed or faucet controlled system, it is to be understoodthat the invention is not limited to faucet controlled systems but may be applied to open pumplng. j

It has been customary; in the mostusual form of pumpfor this purpose; to place the controlling yalves for compressed air or other motive fluid directly upon the head of the pump. Separate head pumps have alsobeen developed wherein the controlling valves for admitting and exhausting compressed air are located at the head of the well, but such installations have not been wholly satisfactory. One great difficulty that exists in the separate head type of pump as'previously constructed is the danger of the pump running away or having a blow-over of compressed air. In the separate head type of pump the control exercised by a float or other level responsive means in the pump can be transmitted only with great difficulty to the head of the pump. In fact in many pumps of this type no such control exists. According to my invention I- transmit this control through fluid pressure, preferably pneumatically, and hence thecontrol may be transmitted through a relatively great distance without difficulty. According to the present invention I control the operation of the main air valve mechanism by means responsive to the flow of motive fluid. Broadly my invention contemplates controlling the main air valve mechanism by means responsive to fluid flow either that of the motive fluid or that of the water. It is well known that during the cycle of operations of a pump of this character the following phenomena occur.

. 1. Upon filling (exhaust stroke) the air 1s expelled by the entering water which moves in by submergence pressure. I Vhen the pump is full, water ceases to flow in, and air ceases to flow out. Either of these two features may be employed as guides for shifting the main valve mechanism to close the exhaust and open the air admission valve.

.2. Upon discharge (discharge stroke) the air flows into the pump and the water flows out. By providing a low level controlled shut-off valve the outflowof water and the inflow of air may be stopped when the discharge is complete. Either of these two features may be employed as guides for shifting the main valve mechanism to close the admission valve and open theexhaust pipe. In each case ,the stoppage of flow of either the compressed air orthe water marks a control point to which the shifting of the main valve may be made responsive.

I provide as a means sensitive to said stoppage of flow, a suitable flow meter so arranged as to secure suitable shifting of the main valve mechanism, upon the occurrence of a predetermined rate of flow as measired by said flow meter. More specifically, I have applied the control of this flow meter to the exhaust valve construction of the pump, and have correlated certain other means cooperatin therewith for governing the admission va ve. As a further feature of novelty, I have arranged the flow metering device so as to be responsive, first, to inflow, and second, to outflow of motive fluid employing the reverse movement through a single orifice.

In the preferred form of the invention which I shall illustrate and describe hereafter the pump strokes are controlled by the flow of air to and from the pump chamber.

In order to acquaint those skilled in the art with the manner of constructing and using one form of my invention I shall now describe a specific embodiment in connection with the accompanying drawings, in which Figure 1 is a diagrammatic illustration of a system embodying my invcuiion in which the control of the main valve is exercised by means responsive to flow of the motive fluid;

Figure 2 is an enlarged elevational view of certain parts of the systemysaid'parts being shown as connected together;

Figure 3 tion of the cut-off valve;

Figure 4 is a similar view of the control valve;

Figure 5 is a similar view through the top.

1 of the paper in Fig. 3; showing the strainer:

and

Figure' 8 is a sectional view of anoveh form of floa-t which is particularly valuable in displacementpumps.

As'shown in Figure 1, the pump 1 is submerged in the water of the'well 2.

An air supply pipe 3 is'oonnected between the pump 1 and a. control valve mechanism l: which controls the admission and exhaust of motive fluid to and'from the pump 1 through the pipe 3. Compressed air is stored in a suitableu'eservoii 21I1C1'1S supplied through a' reducing and control valve 6 and a shut-elf valve 7 to'theniain valve mechanism 1. The reservoir 5*1S"C011l1(t 8(l through the reducer and'cdntrotva'lve 6 and pipe 8 to'the pressure"regulated'contreller 9 which-governs the 'openingatnd closing of thecircuit for the motor 10;w'hichmotor is belted or otherwise connected to the air compressor 11, this Compressorwlelivering air thr'oughthe valve body 12 to' the tank 5. "The pressure regulated controller '9 operates not only as a controller for the electric circuit of the motor'lO, but also as an unloader and shut-oft" va lve' for the compress-- 'sor -11.

' The tank 5 is'connected by'pipe 13 to the pressure reducing valve 6 and this valve in turn is connected to theshut-offvalve 7 thmugh pipe 14. The shut/off valve 7 in turn is connected to the main controller mechanism 4 througlrthe pipe 15.

On the water discharge side of the pump,

there is provided a connection through the pipe 16 to the steady flowchamber '17, which steady flow chamben'communicates pipe 18 which is the distributing pipe running to the outlets located in" the residence x or the like, these outlets inthis case being shown as a faucet 19 and a fire hose 20.

The compressed air reservoir 5 is further connected through asuit-able manually coniThe unloader and cut-off valve 91'2 specifically disclosed and claimed in my co- IS a longitudinal vertical secwith present invention, this being disclosed in detail and claimed in my co-pending application, Serial 493,566, filed August 19 1921. is

pending application No. filed March 30,1921.

The shut-off valve 7 is connected by a pipe 24 to the steady flow chamber 17 for the purpose of shutting off the flow of air to the pump 1 when the pressure in the steady flow chamber 17 rises to the predetermined value.

The pump l-is a single cylinder pump of the'type disclosed in my prior patent or in certain co-pending applications. It comprises an outer-cylindrical sleeve 25 of seamless brass or'bronze, although a-ny other material may be used; havin g the be ad casting 26-and the foot -east-ing"27securedto the ends thereof with suitable :gaskets' 2S and i 29. The head member 526M138 a central screw socket 3O fon'receiving the upper threaded end of the water discharge pipe :31 which pipe is connected at its lower end to the valve 1 box "32 which communicates 'tlirough'three po-rts'33 with the interior of the pump chamber. This valve box isclosed at' its 'lower'end' and is provided with a threaded boss 34 into which is threaded a stud 35', this stud passing through an axial bore and sleeve formed inthe foot cast ng 27 and having a suitable nut 36 threaded upon the lower end thereof to place the pipe 31 under tensionthus holding the head-and foot members 26--'2T' firmly upon the sleeve 25. Theupper'end of the stud 35 is-machined down to form a'guide for the inlet water check'valve37 which is provided with a conical spring 38 tending to close the valve 37 upon the annular seats 3940. Be

tweenthe annular- seats 39 and 40 is a Water -inlet port 41 for permitting the entry of water into the pumping chamber' formed on the inside of the sleeve 25. A metal screen 43' is held in place by the nut 36, this screen being preferably formed in conical shape and made out ofperforated sheet metal. The three water outlet. discharge passageways in the valve box :52 are adapted to be simultaneouslyclosed off uponthe occurrence of low level CO'Hdlt/lOII. in the liquids to be pumped, this sheath being continued at the upper and lower ends to form the connecting necks t9 and and the valve discs or members 45 and 51 being secured to said necks. Hard rubber sleeves 52 and 53 are mounted in the inner bore of said ill) float member for the purpose of guiding the same upon the water discharge pipe 31.

ks disclosed in my co-pending application. Serial No. 499.810, filed Sept. 10, 1921. the rubber valve discs 51 and 45 may be backed up by rings made of either metal or rubber.

The head member 26 is provided with a water discharge passageway 55 which communicates with the water discharge pipe 31 on the interior of the pump and through the valve box 32 with the pumping chamber itselt. At its upper end the discharge passageway terminates in a port which is controlled by the check valve 56, this check valve having a yielding face 57 engaging a suitable valve seat surrounding the valve port and having a guiding stem 58 projecting through said port A spring 59 tends to hold the check valve normally closed. At the upper end the check valve has a stem 60 guided in a suitable guide 01 mounted upon a spider threaded in the upper threaded socket- 62. The water discharge pipe 16 is threaded into said socket.

The head member 26 is further provided with a threaded socket ('33 into which is threaded the air pipe The air pipe 3 connnunicates with a passageway tit leading to a circular port surrounded by the annular valve seats (36-6T. These valve seats are adapted to be engaged by the upper valve member 51 carried on the float member 46 for the purpose of obstructing the passageway of water into the port The valves 45 and 51 need not be absolutely tight particularly for open pumping. It is sufficient that they merely obstruct or hinder the passageway of the fluids which they are intended to shut otl'.

The cut-oil alive 7 shown in detail in Figure 3 has an inlet passageway 68 comi'nunicating with the air pipe 11 coming from the reservoir and a discharge passageway 09 leading to the air pipe 17 which communicates with the main control valve mechanism 1. The main body 70 of the cut-otl valve 7 has a cap member T1 with a depending barrel 72 mounted in a central bore of the body 70. A, frame member 73 is secured to the bottom ot the valve body 70 by a threaded stud 74 which threads into a suitable socket in the bottom of the body 70 with a yielding gasket 75 interposed between the end of the stud and the bottom of the socket.

The barrel member 72 is provided with the ports 76 and with a central valve port 77 which comn'mnicates by way of a passageway 78 to a passageway 79 which leads back to the valve body 70 and colmnunicates with a passageway 80 Which forms a continuation of the inlet port 08. The valve seat T? is adapted to be controlled by a valve 81 which is mounted upon a sliding: piston 2 mounted in the cylinder T2. The lower edges of the piston 82 form a skirt which is adapted to engage the yieldable packing 7a to seal ofl the air space 81 which surrounds the depending cylinder 72 from the opening 87 through said packing 75.

The piston 82 is adapted to be moved upwardly to close off the port to and to cause the valve 81 to close the port 77 by means of a rod 86 which passes through a tubular guide 87 mounted in the frame 73 and en gages at its lower end the movable piston head 88 which rests upon the diaphragm 89, this diaphragm closing the fluid pres' sure chamber 90 which communicates by way of passageway 91 and pipe Q-t with the steady flow chamber 17, the purpose of this connection being to close ott the cut off valve 81 when the pressurein the steady tiowchamb er rises to a predetermined maximum.

The rod 86 is threaded at its lower end as indicated at 92 into the spring plate 93. this plate being engaged by the end of the helical spring 94 which is compressed be tween said plate 93 and the upper plate 95. The upper plate 95 is threaded upon the tubular guide 87 and held in place by means of the lock nut 96, said plate 95 being provided with means in this case consisting of capstand sockets for adjusting the pressure which the spring applies to the piston plate 88. The plate and lock nut 96 on the threaded tubular guide 87 thus forms means for adjusting the cut-off valve for various pressures in the steady flow chamber.

The cap casting 7 has a transverse bore 98 which is closed at its outer end by a screw plug 99 hearing a screen 100 for the purpose of preventing impurities from passing with the compressd air into the pumping chamber 42 and there coming in contact with the water. This screen is removable for cleaning purposes.

The control valve 4 which performs the function of admitting air to and exhaust iug air from the pumping chan'iber 12 for each stroke of the pump has a con'ipound valve and motor structure serving first as an admission valve; second. as an exhaust valve. and third, means for shifting these values at the proper time. This structure comprises a housing made of two parts 101 and 102 having suitable flanges tor clamping be tween them a diaphragm member 103. The casing portion 101 contains a threaded socket 104 for connection with the air pipe 15. An air chamber 105 is formed in said casing section on the right hand side of the diaphragm 103 as shown in Figure at. A valve cage and piston member 100 is clamped on the right hand side of the diaphragm member 103 and a cooperating piston and guiding member 107 is secured on the opposite side of said diaphragm. The p ston member 106 is adapted to enter the cylinlit der portion 108 with which the piston portion 109 makes a close fit. Grooves 110. are cut longitudinally of the cylinder portion 108 to a point near the end of the same. The piston portion 110 is adapted. however, to overrun the ends of these grooves and form a seal between the admission chamber 111 and the diaphragm chamber 105. The piston member 109 is hollowed out to form a guide for a valve structure 112 which is provided with grooves or openings 113 to permit the movement of the exhaust air through the same to the atmosphere as will be described more in detail later.

The piston member 109 has a head portion 114; which has an exhaust passageway therethrough with a valve seat 116 surrounding the inner end thereof, this valve seat being adapted to be engaged by the exhaust. valve member 117 forming an axial extension ot the member 112.

An admission passageway 118 communicates with the air inlet pipe 15 and this passageway has a valve seat 110 adapted to cooperate with the admission valve 120. It will be noted that the admission valve 120 is in the. form of a plug or poppet valve which closes against the entering pressure.

The casing portion 102 has a diaphragm chamber 121 on the left side of the diaphragm 103 as viewed in Figure 1. this chamber communicating first with the diaphragm chamber 105 through a restricted port or passageway 122 formed through the cooperating flanges and the interposed diaphragm 103, the chamber 121 communicates furthermore with the pipe 3 which leads to the pump 1. It communicates also by way of a passageway 123 with a cylinder 124' in which lies a movable piston 125. The end or the cylinder is closed off by a cap 126. The piston 125 is arranged to engage it stop 127 to limit the movement thereof. The stem 128 ot the. piston 125 is adapted to engage a boss 129 which forms a continuation of the piston 130, this being an extension of the member 107. The piston member 130 tits in a cylinder in line axially with the cylinder 124, this piston being adapted to engage a stop member 131 for limiting the motion of the piston 130 and the diaphragm 103 to the left. as viewed in Figure 4. The boss 12!) is formed upon a head member 133 which is threaded into the end of the piston memler 130 and is provided with a plurality of passageways 13s for permitting the escape of the exhaust air into the space between said pistons 125 and 130 and out to atmosphere by way of the exhaust openings 132.

This head member 133 has an extension inwardly for limiting the motion of the member 112 and for guiding the spring 137 which lies between said head member 33 and the member 112.

The admission chamber 111 con'nnunicates with the diaphragm chamber 105 through a check valve construction comprising the passageways 138 and 139 connnunicating with said respective chambers and the valve port 140 formed in the removable plug 141. This valve port 140 is controlled by the ball check valve 141, the ball valve 141 being prevented from blocking the passageway 138 by means of a pin 142.

Assuming that the system is in correct condition for operation, the operation may be described as follows:

The compressor 11 discharges compressed air into the tank 5 until the same is brought to a suitable pressure after which the automatic controller anl unloader stops further operation of the compressor and unloads the same. Use of compressed air from the tank 5 either for the water supply system or for the tire hose 23 causes automatic rd charging of the same in a manner which is well understood by those skilled in the art.

The pressure reducing valve (3 normally maintains a suitable pressure upon the water .system, but this may be increased by operation of the by-passvalve 21, as explained in my co-pending application above enumerated.

Assume that the faucet 19 opened and the pressure in the steady flow chamber 17 is reduced, the cut-off alve T will be opened. admitting air to the control valve 1 which in turn causes intermittent expulsion of .water from the pumping chamber in the pump 1. Vhen the pressure in the steady flow chamber 17 drops to a predetermined value, the sprin 94 overcomes the pressure on the diaphragm 89 (see Fig. 3) permitting the air entering by way of the pipc 14., passageways (39, 80 and '79 to open the valve 81 and force the piston 82 downward ly. As soon as the valve 81 is cracked away from its seat, the air entering the (llflliilk-r above the piston 82 tones the same down quickly because of the increased-area upon which said air operates. immediately uncovering the ports 76 to permit the t-Mliijt of air to the. surroui'idiug space 84' and the passageway 09 which leads to the control valve 4. When the piston 82 is forced downwardly, the skirt 83 cooperates with the yielding gasket 75. closing off the escape of air through the opening 85 through which the rod 80 projects. Due to the ditlerence in area of the two closures, namely, the valve 81 and the skirt 83, the valve 81 will not be opened until a material drop of pressure in the chamber 90 has occurred. this drop of pressure being responsive to the drop o." pressure in the steady tlow chamber 17. In a similar manner, the closing of the valve 81 will be retarded by the relatively large area of the skirt. 83 on the acking 75 until the pressurein the steady lbw chamber 17 l'lSO-a ltlt) lid to a predetermined value which may be appreciably higher. In other words. the minor variations in flow such as may occur between pump strokes and the drawing oti' of small amounts of water, such as may occur due to leakage or the drawing of an occasional glass of water. will not necessarily compel he system to start the operation of the pump 1.

Assume, however. that the faucet 19 is wide open and is drawing water from the steady flow chamber 17 to such an extent as to cause opening of the cut-off valve 7, air will pass from the air reservoir through pipe 14 through the cut-off valve 7 through th pipe 15 to the control valve 1 from which it will be periodically shut 01f and admitted to the pump 1. The operation of the control valve 1 is follows:

Air enters by way of the pipe 1.5 and passageway 118 tending to open the admission valve 120. A small amount of air will leak past this valve. quickly raising the pressure in the chamber 111. acting upon the piston head 111 and forcing the diaphragm 103 towards the left as viemed in Figure 4. This permits live air to pass by way of the groove 110 into the diaphragm chamber 105, still further tending to force the same to the left as shown in Figure -1, and to hold the same so that air may be freely admitted. The engagement of the piston member 130 with the stop 131 limits the motion of the diaphragm 103 to the left. Live air passes through the port 122 of which one. or more may be provided. entering the diaphragm chamber 121 and passing through the pump chamber 12. The entry of this air into the diaphragm chamber 121 quickly builds up the pressure there n and in the pumping chamber -12 tending to expel the mater therefrom. At this time we will as- M11110 that the pumping chamber 42 is full and that the float and connected valve structure is at the upper end of the pumping chamber. This pressure in the diaphragm chamber 121 and pump chamber 12 also operates in the cylinder 124 against the piston men'iber 125 tending to shove the diaphragm and connecting structure to the right, as shown in Figure 4. However, so long as there is a flow of air due to the ditference in pressure between the two sides of the diaphragm 103, this piston will be inetfective to close the admission valve 120.

The exhaust valve 117 is held closed during these operations by the spring 137. The pressure of the air upon the relatively small area of the exhaust valve being insutficient to cause opening of the same. As soon as the Water has been expelled from the pumping chamber. the tloat 17 will have lowered to the low level position causing the valve member to shut off the valve ports 33, whereupon further expulsion of water from the pumping chamber 42 will cease and further inflow of air will also cease as the pressure in the pumping chamber 42 tends to rise to the pressure of the incoming air. tonsetpiently, the difference in pressure which has heretofore existed upon the two sides of the diaphragm 103 will substantially disappear the pressures equalizing, and the admission valve 120 will begin to close. The parts are so proportioned that an absolute equality of pressure upon the two sides of the diaphragm does not need to exist, in fact, the operaticn which shall now be described is desirable before actual equalization does occur in order that there may be a margin of operation over which the device may operate. The piston 125 having greater pressure operating thereupon than Was previously available. now forces the diaphragm 103 to the right, closing off the admission valve 120 by engagement with its seat 119. It will be noted that the pressure of the piston 125 is transmitted through its stem 128, through the stem 129, to the head member 133 of the piston member 130, and this pressure is transmitted to the piston member 109 which has the valve seat 116 cooperating with the exhaust valve 117. The piston 125 moves over to the right. engaging the stop 12? and holding the exhaust valve seat 116 away from the exhaust valve 117. but holding the admission valve 120 against its seat 119. The result is, that the opening of the ex haust valve permits the pressure in the chamber 111 to be reduced and the pressure in the chamber 105 is quickly reduced due to the passage of the air through the check valve structure 140-141, th ough the chamher 111, pastthe valve seat 116, out through the passageways 113. through the passageways 134 in the head member 133 and out the exhaust passageways 132. The result of. this reduction of pressure on the right hand side of the diaphragm 10?) over the pressure existing on the left hand side of the same results in continued holding of the diaphragm in its righthand position whereby the exhaust valve 116-417 is maintained in open position until such difference of pressure is substantially equalized. Air from the pun'ipin'g chamber 42 passes up through the pipe 3 into the diaphragm chamber 121 through the restric ed opening 122 and out through the check valve and exhaust valve structures as previously de scribed. As soon as the pressure in the pumping chamber 42 drops below the submergence pressure, Water begins to enter the pumping chamber and raises the float member with its connected valves causing the float 416 to rise and close off the annular passageway so that further movement of air out through the pumping chamber 42 is prevented, or at least materially reduced.

l pon this occurrence of stoppage of flow, the pressures upon the two sides of the diaphragm 103 tend to equalize with the result that the spring 137 overpowcrs the piston 125 and the pressure on the diaphragm 103, that is, in the chamber 121, causing the diaphragm 103 and piston 125 and connected parts to move to the left, thereupon closing off the exhaust valve 116-417. This is accompanied immediately by a swinging of the admission alve 120 to the left as previously explained, and the making of an admission stroke in the pumping chamber 42. The pump thus continues to operate taking in and expelling water until the pressure inthe chamber 17 rises to a value where the cut-off valve 7 operates. This valve operating with a snap motion, positively stops further admission of motive fluid to the control valve 4 and leaves the pump standing free of pressure and it qu ckly fills with water for the next stroke.

It will be appreciated at once that the high and low level-valve mechanism in the pumping chamber cooperates with the diaphragm 103 and connected part to cause a shifting of the diaphragm 103 to the right or to the left as the case may be. whenever the stoppage of air into or out of the pump, as the case may be, occurs. In other words, the high and low level control are trans mitted pneumatically through the column of air which performs the operation of pumping to cause the individual pump strokes.

The diaphragm 103 is the main motor for operating the valve mechanism and the ac tion of this diaphragm is supplemented in one direction, namely, to open the a ln1ission'valve by the piston head 114 which serves as an auxiliary motor. and in the other direction for closing the admission valve and for opening the exhaust valve by the piston 125 which serves also as an auxiliary motor member. These auxiliary motor members serve to initiate motion of the valves in one direction or the oth r. and the main diaphragm or motor member 103 serves to complete the motion or hold the valve in the direction determined by the action of the motor mechanism. This controlling valve 4 may be made very sensitive because of the relatively great area which is or may be exposed to the compressed air either on admission or exhaust. In fact. theoretically. itmay be made as sensitive as desired.

For open-pumping the cut-off valve 7 may be omitted and a hand controlled valve may be substituted therefor. or the stopping and starting of the pump 1 may be controlled by stopping and starting of the compressor 11.

In Fig. 8 I have indicated a metallic float member 150 which is made preferably of thin sheet metal. A float of metal. when subjected to pressure,is apt to crush. weight of metal required to make a lloat strong enough not to collapse under the pressures to which it may be subjected renders thefloat relatively heavy and greatly reduces the buoyancy thereof. I propose to make a float of very thin stock and per mit the pressures to equalize upon the two sides thereof. This is feasible, since air, even when compressed, is much lighter than the water at the same pressure. In Fig. 8 l have shown a thin metallic float having the valve discs 51 and 45 at the upper and lower ends thereof respectively for co-operating with the high level and low level ports 65 and 33,respectively. These valves are mounted upon necks 151 and 152. which hold the valve discs 51 and 15' relatively loosely to permit them to seat upon the re spective ports. The main body of the valve is made of light weight stock and is completely sealed oil with the exception of an opening formed by a small tube 153 passii-ig through the top wall of the float and extending down to a point adjacent the bottom of the hollow part of the floatv It will be seen at once that the tube 153 which permits communication between the interior and the exterior of the float will allow the pressures to equalize, substantially submergence pressure of water within the pumping barrel 25 over the corresponding level of water on the inside of the float 150. Hence, it can be seen. since the float 1S relatively short, that the pressure tending to drive any water through the float into the interior thereof, would be less than the height of the float in inches of water. Thus, assume that the float 150 were floating rehe tively low in the water, as indicated by the water level 154, and assuming that there were a leak somewhere in the walls of the float, the greatest pressure that could prevail tending to force this water into the float, would be the height of the level 15 above the leak in the float.

Assuming that some water did [ind its way into the float and stood at the level indicated at the line 155. During the pres sure stroke of the pump. the interior of the float would be filled with compressed air under the same pressure as prevails outside the float. Then, as soon as the exhaust valve opens, the pressure of the air in the pumping chamber is quickly reduced and the air contained within the float member 150 expands. If any water has leaked into the float, it will naturally tend to seal the lower end of the pipe 153 and the expansion of the air in the float will drive said water out by pneumatic displacement. The float its-elf thus becomes a small pneumatic pump operating in parallel with the main pump to keep the interior of the float pumpedont.

The i till The ltmdamental idea involved is that of metering the rate of air inflow, and when the rate of inflow drops to a predetermined minimum. to shift the main control valve from admission to exhaust condition. Then, in turn. I meter the rate it outflow of the exhaust. and when said rate of exhaust drops to a predetermined minimum. I shitt the main control valve "from exhaust to admis sion position.

The flow restricting orilice r22 serves the same purpose as the orifice ot a flow meter in setting up difl'erences in pressure responsive to flow. The diaphragm 103 is a member responsive to said differences in pressure. and the main valve is shifted to one position or the other under the control of the meter, which meter is a true gauge or indication of emptying and filling of the main chamber, because the movement of the float to low level position shuts off further discharge of liquid from the pumping chamber. and hence. shuts off further entrv of live air. That is to say. the rate of air inflow drops to snbstantialh zero at that point. The flow meter is responsive to this. and it closes the admission valve and opens the exhaust valve.

Then the air flows out. The same flow meter no w measures the outflow of air. This outflow of air continues until the liquid has again filled the pumping hamber. lVhen the float 4G shuts ofl' the further entry of liquid and. hence. the outflow of air to through the meter drops to substantially zero. The flow meter then responds to this condition and closes th exhaust valve.

The piston 125 and the piston 109 are auxiliaries working in connection with the flow meter. more speciticall for assisting in the operation of the admission valve.

I wish to call attention to the fact that the present control mechanism for making the individual strokes of the pump is not to be limited to an air displacement pump. but could be employed in a motor in which a piston is driven down by the entering; air and which is returned by some means, either a iv-wheel. a. spring or the like. for exp-elliunthe air on the exhaust stroke.

I do not intend to be limited to the details shown and described.

I claim:

I. In combination. a pumping chamber. a source of motive fluid. a flow r-estrictioi'i between said source and said chamber. a main valve mechanism for motive fluid. and means responsive to the flow of motive fluid with respect to the pumping chamber for shifting said main valve mechanism to exhaust position said means comprising a diaphragm subject on opposite sides to the pressure prevailing upon opposite sides of the flow restriction.

2. In combination. a pumping chamber, a

source of motive fluid, a flow restriction bc tween said source and said pumping chamber, a main valve mechanism for motive fluid. means responsive to the flow ot motive fluid tor shitting said main valve mechanism to exhaust position, said means comprising a diaphragm subject on opposite sides to the pressures prevailing upon opposite sides of the flow restriction. and level controlled means governing said How responsive means.

In combination. a pumping chamber, a source of motive fluid. a flow restriction between said source and said chamber, a main valve mechanism for motive fluid. means responsiv e to the flow 0t motive fluid tor shitting said main valve mechanism, said means comprising a diaphragm subject on opposite sides of the pressure prevailing upon opposite sides of the flow restriction, and means responsive to low level condition in the pumping chamber for controlling said re sponsiv-e means to shift the main valvc mechanism to exhaust position.

4. In combination. a pumping;- chamber. a source of motive fluid. a flow restriction be tween said source and said pumping chamber. a main 'alve mechanism. level controlled means in the pumping chamber for changing; the rate of flow into and out of the pumping chamber, and means responsive to pressure diflerence corresponding to the rate of flow into and out of the pumping chamber for shifting the main alve mechanism.

5. In combination, a reciprocator pressure operated device comprising a chamber. a sour e of motive fluid. a flow restriction between said source and said chamber. a main valve mechanism. said reciprocatorv device having means for changing the rate of flow into and out of the device. and means responsive to pressure ditlerence corresponding to the rate of flow into and out of the device for shifting the main valve mechanism, said means con'iprisingr a diaphragm subject on opposite sides to the pressure prevailing upon opposite sides of the How 1e striction.

6. In a device of the class described. a re ciprocatory device actuated by pressure fluid, a main valve mechanism for admitting and exhausting pressure fluid to and from the device, said device having means for stopping the flow of pressure fluid at the end of a stroke. and a motor member controlled by stoppage of the pressure fluid for shifting the valve mechanism.

7. In a device of the class descr bed. a reciprocatory device actuated by pressure fluid, a main valve mechanism for admitting: and exhausting pressure fluid to and from the device. said device having means for stopping the flow of pressure fluid at the end of a stroke. and a motor member con trolled by stoppage of the pressure fluid for iii shifting the valve mechanism, and auxiliary motor means for increasing the power of the motor in one direction.

8. In a device of the class described, a diaphragm having a pair of chambers on opposite sides, said chambers having a constantly open restricted connection between them a main valve structure actuated by said diaphragm, said diaphragm having two stages of motion in each direction. one stage of motion in the first direction closing the admission valve, the second stage 01": motion opening the exhaust valve, spring means for opposing the second stage of motion independently ot the first stage.

9. In a device of the class described, a diaphragm having a pair of chambers on opposite sides, a restricted passageway between said chambers, said passageway being invariably open, a main valve structure controlled by movement of said diaphragm, said diaphragm having two stages of motion in each direction, one stage of motion in the first direction closing the admission valve, the second stage of motion opening the exhaust valve, and spring means for opposing the second stage of motion independently of the first stage of motion.

10. In a device of the class described, a diaphragm having a pair of chambers one on each side, a restricted passageway between the chambers, said passageway being open, a main valve structure controlled by said diaphragm, said diaphragm having two stages of motion in each direction, one stage of motion in the first direction closing the admission valve, the second stage of motion opening the exhaust valve, and spring means for opposing the second stage of motion independently ot the first, one stage of motion in the reverse direction serving to close the exhaustvalve, and the second stage of motion in the reverse direction serving to open the admission valve.

11. In a device of the class described, a diaphragm having a pair of chambers one on each side, a restricted passageway between the chambers, said passageway being open, a main valve structure controlled by said dia r hragm, said diaphragm having two stages of motion in each direction. one stage of motion in the first direction closing the admission valve. the second stage of motion opening the exhaust valve, and spring means for opposing the second stage. of motion independently of the first, one stage of motion in the reverse direction serving to close the exhaust valve, and the second stage of motion in the reverse direction serving to open the admission valve, and a reciprocatory device connected on one side of the diaphragm and a source of motive fluid connected on the other side of the diaphragm througn the admission valve.

12 In combination, a diaphragm. a din" phragm chamber on each side of the (laphragm, a restricted passageway normally open between the chambers, an auxiliary chamber, a source of motive fluid, an admission valve movable by said diaphragm for connecting the source of motive fluid to said chamber, auxiliary motor means for connecting the auxiliary chamber with one diaphragm chamber an exhaust valve member connected to the admission valve. a cooperating exhaust valve member movable with rc spect to said first member and connected to the diaphragm for connecting said auxiliary chamber with atmosphere, and a check valve connection between the one diaphragm chamber and the auxiliary chamber.

13. In combination, a diaphragm, chainbers on opposite sides of the diaphragm having arestricted passageway between them, an admission and an exhaust connection to one of said chambers, a connection leading to a reciprocatory device on the other chamber. and a valve device for said admission and exhaust connection, sa d valve device being connected to the diaphragm, said diaphragm being shifted by preponderance of pressure on admission to close the exhaust valve and open the admission, and being shifted by substantial equili- Zat on of pressure or failure to maintain said preponderance to connect the first chamber to exaust.

14. In combination, a pair of diaphragm chambers, a diaphragm separating said chamber, an admission and exhaust valve device for admit-ting motive fluid to and from one of said chambers. said valve mechanism being operated by said diaphragm, a restricted connection between said chamber. and a working chamber for receiving and exhausting motive fluid connected to the other chamber.

15. In combination, a pair of diaphragm chambers, a working chamber connected to one of said diaphragm chambers, said chainbers having a normally open restricted pas sageway between them and a diaphragm separating the chambers, main admission and exhaust valve mechanism connected to the diaphragm and having cooperating ports communicating with the second diaphragm chamber.

16. In combination. a pair ot' diaphragm chambers, aworking chamber connected to one of said diaphragm chambers. said chambers having a normally open restricted passageway between thorn and a diaphragm separating the chambers, main admission and exhaust valve mechanism connected to the diaphragm and having cooperating ports communicating with the second diaphragm chamber, and means for initiat ng motion of the valve mechanism for admit ting pressure to the first chamber.

17. In combination, a pair of diaphragm chambers, a working chamber connected to one of said diaphragm chambers, said chambers having a normally open restricted passageway between them and a diaphragm separating the chambers, main admission and exhaust valve mechanism connect-d to the diaphragm and having cooperating ports communicating with the second diaphragm chamber, and auxiliary motor means to assist the diaphragm to close the admission valve and open the exhaust valve.

18. In a shut-otl valve, an admission port, an admission valve, a piston tor said valve, a spring loaded diaphragm, a thrust rod from said diaphragm to said piston, an exhaust passageway about said rod, and a. seat about said passageway, said piston having a skirt for engaging said seat to close ofl' said passageway.

19. In a shut-off valve, a main body portion, a cap portion, and a yoke portion, said yoke portion having a diaphragm and a connection on one side of the yoke providing a passageway communicating with the diaphragm, a guide mounted in the upper portion of the yoke member, a spring surrounding said guide and opposng the diaphragm, a rod connected to the diaphragm passing up through said guide, a yieldable seat about said rod, a cylinder in the main body portion of the cut-ofl valve, a piston in said cylinder having a skirt for engaging the seat about said rod, a valve mounted on the piston, a valve port controlled by said valve, a passageway from said port throu h said cap member, and a removable cylin rica-l screen mounted in the cap member.

20. In a shut-off valve, an air inlet connection, an air outlet connection, a piston and valve lying between said connections, a cap member for the valve, said cap member having a passageway therein. and a cyl ndrical screen obstructing said passageway, and a plug member screwed into the wall of the cap member supporting said cylindrical screen.

21. In combination. a diaphragm, a pair of chambers for the diaphragm, a constantly open restricted communication between said chambers, a working chamber connected to one of said diaphragm chambers and admission and exhaust valves connected to the other of said diaphragm chambers, said re stricted communication between the diaphragm chambers being adapted to convey all of the motive fluid to and from the working chamber.

22. In a pumping system, a pumping chamber, an exhaust passageivay, an exhaust valve therefor, a flow meter connected in said passageway and controlling the exhaust valve to close the same when the rate of flow out of the exhaust passageway drops to a predetermined value.

23. In a device of the class described, a fluid passageway, a flow meter connected to said passageway, and a valve for closing off the passageway when the flow therethrough drops below a predetern'iined value, said valve being controlled by said meter.

24. In combination, a chamber, a source of fluid pressure, a passageway between said source and said chamber, and a flow meter comprising means responsive to a pressure difference corresponding to a. predetermined rate of flow for shutting oil the source of fluid pressure from the chamber.

In combination, a. chamber, a source of fluid pressure, a passageway between said source and said chamber, an exhaust passageway, and a flow meter comprising means responsive to a pressure difference correspond,- ing to a predetermined rate of flow through the exhaust passageway for shutting oit the exhaust passageway. 7

26. In a. pumping system, a pumping chamber, an exhaust passageway, an exhaust valve therefor, a flow meter connected in said passageway and controlling the exhaust valve to close the same when the rate of flow of motive fluid out of the exhaust passageway drops to a predetermined value, and means in the pumping chamber for controlling the rate of liquid flow out of the chamber.

27. In a. pumping system, a working chamber, a source of fluid pressure, an exhaust connection, a main air valve for connecting the chamber alternately to pressure and exhaust, and a fluid meter sensitive to pressure difference corresponding to fluid flow controlling said main air valve.

28. In a pumping system, a pumping chamber, a source of fluid pressure, an exhaust connection, a main air valve for connecting the chan'iher alternately to pressure and to exhaust, a fluid flow meter for con trolling said main valve, and level controlled means within said pumping chamber for controlling fluid flow.

29. In combinatioi'i, a pumping chamber, a source of motive fluid, an admission valve therefor, a. flow meter in the connection between the source of motive fluid and said chamber, and means controlled by the flow meter for holding the admission valve open while liquid is being discharged from the pump.

30. In combination, a pumping chamber, a source of motive fluid, an admission valve therefor, a flow meter in the connection brtween the source of motive fluid and the chamber, and means controlled by the flow meter for holding the admission valve open while motive fluid is flowing into said pumping chamber.

31. In combination, a pumping chamber, a source of motive fluid, an exhaust valve for the chamber, an exhaust passageway controlled by said alve, a flow meter in said exhaust passageway, and means controlled by said flow meter for holding the exhaust valve open While liquid is entering the pump.

32. In a pumping system, a pumping chamber, a source. of fluid pressure, an exhaust connection, an air valve for connect ing the chamber alternately to pressure and exhaust, and a fluid pressure actuated means responsive at a predetermined rate of fluid tow out of the chamber to hold the exhau1zt valve open, and responsive to a predetermined rate of fluid flow into the chamber to hold the pressure connection open.

33. In combination, a pumping chan'ibcr, a source of compressed air, means for step ping the outflow of compressed air at low level or liquid in the pumping chamber, a pressure sensitive element, a flow restricting orifice between opposite sides of the chamber, and valve mechanism for admitting or exhausting compressed air to or from the chamber, said mechanism being controlled by diflerenices in pressure upon opposite sides of the chamber.

34. In combination, a. pun'iping chamber, a. source of compressed air, a. valve box, a movable pressure responsive element dividing the box into two chambers, a restricted connection between the chambers, an air admission valve opened by superior pressure in the second diaphragm chamber.

35. In combination, a pumping chamber. a. source of compressed air, a valve box, a movable pressure responsive element dividing the box into two chambers, a secoml movable pressure responsive element between one of said chambers and atmosphere, a restricted connection between said chambers, an air admission valve opened by superior pressure in the second diaphragm chamber, and an air exhaust valve opened by a substantial equalization of pressures in said chamber, and held open by an excess ot' pressure in said second chamber over atmosphere.

236. In combination, a source of fluid pressure. a pumping chamber. a. main. valve for the pun'iping chamber, a fluid meter rcspoir sive to pressure difference corresponding to the rate of fluid flow into or out of the pump ing chamber and independent of the fluid pressure controlling said main valve.

37. In combination. a closed casing having an inlet: and an outlet, means for passing fluid through said casing, means comprising a flexible plate disposed in said casing and containing a flow restricting orifice for said fluid, and a valve controlled by movement of said plate.

38. In combination, a source of fluid pressure, a conduit for conveying a flow of fluid from said source, a casing in said conduit, a flexible diaphragm having a flow restricting orifice therein, and means moved by said diaphragm upon the occurrence of a predetermined fluid flow through said orifice.

39. In combination, a substantially closed chamber, a source of fluid pressure, a con duit for connecting said source and said chamber, a valve in said conduit, a device responsive at a predetermined mininmm flow of fluid through said conduit for closing off said valve.

40. In combination, a chamber adapted to contain fluid under pressure, a conduit leading therefrom, a valve in said conduit, means holding said valve open, and means for closing said valve when the rate of flow drops to a predetern'iined minimum.

41. In combination, a working chamber having a movable piston, a source of fluid pressure, a conduit connecting said chamber to said source, a valve in said conduit, and means in said conduit for shutting ofl said valve when the flow is reduced to a predetermined minimum.

&2. In combination, a sealed chamber, a source of fluid pressure, a conduit from the source to the chamber, a valve in said conduit, an exhaust valve for the chamber, and means in the conduit for shutting off said first valve and opening the second valve upon a predetermined flow of fluid through the conduit.

43. In combination, a chamber, a source of fluid pressure, a conduit from the source to said chamber, a valve in said conduit, and a movable diaphragm in said conduit having a flow restricting orifice, said diaphragm controlling the closing of said valve upon occurrence of a predetermined minimum dit' ference of pressure upon opposite sides thereof.

44. A device sensitive to fluid pressure diflerence corresponding to flow comprising a flexible diaphragm having a flow restricting orifice therethrough.

45. A device sensitive to fluid pressure difference corresponding to flow comprising a flexible diaphragm having a flow restricting orifice therethrough, and means to oppose the movement of said diaphragm.

e6. In combination, a source of motive fluid under pressure, a chamber, a connection for conducting motive fluid to the chamber, a valve controlling said connection, a flow restriction in said connection, and pressure responsive means governed by differences in pressure which correspond to a predetermined rate of flow through the restriction for shifting said valve.

47. In combination, a source of motive fluid, a chamber, a passageway leading from the chamber, a reversible control valve. a connection to the source of motive fluid. and a connection to exhaust, both connections leading to said valve and being alternately opened to and cut off from said passageway, and means responsive to a pressure difference corresponding to a predetermined rate of flow of motive fluid through said passageway into said chamber for shifting said control valve to one position and responsive to a pressure difference corresponding to a predetermined rate of flow of motive fluid through said passageway out of said chamber for shifting said control valve to the reverse posit-inn.

48. In a device of the class described, a working chamber, a source of fluid pressure, an exhaust connection, a main fluid valve for connecting the chamber alternately to pressure and exhaust, and a controlling member comprising a movable member actuated b pressure differences corresponding to flui into and out of the working chamber controlling said main air valve.

49. A device sensitive to fluid pressure difference corresponding to flow comprising a flexible diaphragm having a flow restricting orifice therethrough, means to oppose the movement of said diaphragm and means connected to the diaphragm and movable by said diaphragm and by said first named means.

In Witness whereof, I hereunto subscribe my name this 24th day of October, 1921.

BURTON S. AIKMAN.

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