US2621608A

US2621608A - Apparatus for imposing pressure on liquid

Info

Publication number: US2621608A
Application number: US765101A
Authority: US
Inventors: Mcintyre Frederic
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-07-31
Filing date: 1947-07-31
Publication date: 1952-12-16
Anticipated expiration: 1969-12-16

Description

Dec. 16, 1952 F. MOlNTYRE APPARATUS FOR IMPOSING PRESSURE ON LIQUID 2 SHEETS-SHEET 1 Filed July 51. 1947 It: jizym Dec. 16, 1952 MCINTYRE 2,621,608

- APPARATUS FOR IMPOSING PRESSURE ON LIQUID Filed July 5]., 1947 2 SHEETSSHEET 2 j, 1," M1; a; 7% W I Patented Dec. 16, 1952 UNITED STATES PATENT OFFICE APPARATUS FORIHIPO LIQ 1-4 Claims. (Cl. 103- 223) The object of this invention is to furnish an apparatus by which pressure can be'imposed ona liquid through the agency of pumping means,

SING' PRESSURE ON UID.

Frederic McIntyre, Newton,- Mesa, assignor to Donald B. McIntyre, Wellesley, Mass.

Application July 371', i947, Serial No. 765,101

with protection of the pumping means from cor= rosion by such a liquid, substantial elimination of wearing of the moving parts of the pumping means, and protection of such liquidfrom the possibility of receiving foreign matter from the trolled means for furnishing beverages consisting mainly of water and including flavoring substances. The apparatus is useful also' for maintaining other liquids under constant pressure for For this and analogous uses, a.

other purposes. related object of the invention is to provide means controlled by the pressure head of'the' stored water or other liquid for causing the pumping equipment to operate when the pressure diminishes below'the prescribed degree, and

stopping or reversing the action of the" pumping means when the prescribed pressure has been attained or restored.

Mention has been made here of the use for storing water under pressure because of the fact that there is a present large demand for beverage dispensing units including a' container of water maintained under pressure greater than the usual water service pressure, and the fact that pump makers heretofore have been unsuc cessful in attempting to make a reliable water pump for this purpose. Iron and steel, the usual materials employed in making pumps, are subject to electrolysis or corrosion; and available materials which are immune to electrolysis and.

corrosion wear out quickly and cause endless trouble. They become leaky and unable to maintain the required pressure, and entail high cost for maintenance. The water passing through such pumps may be contaminated by the prod-- ucts of corrosion or wear...

Another illustrative use of the invention is that of delivering liquid which may be highly corro' sive or abrasive-or may contain abrasive solid matter in suspension. Such-liquids, when passed through the pump by which they are delivered, cause rapid wear and materially shortened useful life of the pump.

I have accomplished the objects of preventing corrosion and abrasion, and substantially-eliminating wear of the pumps for serving the foregoing and analogous purposes by isolating the pump elements from the liquid on which pressure is imposed, and interposing" between the pump and the liquid a flexible, impervious; noncorrodible'element and a pressure transmitting fluid which is acted upon directly by the pump and'is both non-corrosive and a lubricant.

"The invention comprises therefore the combi-' nation with a pump of a chamber having a flexible wall or liner, with inlet and outlet" connections for the liquid on which pressure is to be imposed, and connections organized to transmit pressure through a working fluid from the pump to the opposite surface of the flexible wall or liner from that which is exposed to the'liquid' acted upon. In one embodiment the invention further comprises auxiliary equipment for receiving liquid under pressure and controlling the operation of the pump and direction of flow of the working fluid in response to variations of the pressure head of the liquid.

In another embodiment the invention comprises the combination with a pump of a plurality or chambers of the type precedently "mentioned and meansfor directing the pressure" of the Working fluid to the several pressure chambersxin turn.

The accompanying drawings show the principles of the invention in several illustrative em bodiments, and therein.

Fig. 1 is a diagram showing the parts and their operative relationship of an apparatus organized:

to receive and increase the pressure of liquid and contain the liquid under augmented substantially constant pressure for dispensing;

Fig. 1a is a partial diagram of the apparatus shown in Fig. 1 with substitution of a modified fornrof flexible walled chamber and flow con nections thereto from a source and therefrom to the container;

Fig. 2 is a sectional view of a direction control valve iorming'part of this apparatus by which the movement of working fluid to and from the flexible walled chamber ofthe apparatus is controlled:

Fig. 3'isa detail view partly in section of the flexible walled portion, or lining,- of the chamber in which pressure is imposed on theli'quid;

Fig. 4--isa -view'similar in the main te -Fig. 1

but showing analternativemeans for controlling the operation of the pressure imposing means Fig. 5 is a diagrammatic view of the invention embodied in the combination of a pump with'two pressure delivering" chambers and means for a directing the working fluid to the several chambers alternately.

Like reference characters designate the same parts wherever they occur in all the figures.

Referring to Fig. 1, it represents a tank or other recipient in which a supply of liquid, which for the purpose of the present description may be assumed to be water, is maintained under a predetermined pressure for dispensing. A pipe ll enters the side of tank It] for delivering water thereto and a pipe 12 is connected with the tank at a low point for delivery of the water. The tank is otherwise constructed to entrap air in its uppermost portion so that the air is compressed by inflowing water and caused to apply pr ssure to the water.

Water is supplied to the storage tank from any available source, such as the municipal water supply system, by means of a pipe i3. Between the supply pipe 13 and the delivery pipe ii is a compression chamber or accumulator comprising a substantially inextensible shell Hi and an internal flexible liner 55.

Preferably the shell it is made of metal with hemispherical ends and a short cylindrical intermediate portion, designed to withstand a substantially great internal fluid pressure without being distorted appreciably. It may be made as a sphere however, or of other shape provided its walls are adequately strong and stiff to resist rupture or distortion under the pressures encountered. In one embodiment of equipment which I have designed in accordance with this invention, the water pressure is increased from that of the source to 120 pounds per square inch, and the shell of the chamber It is designed to sustain hydraulic pressure of more than 209 pounds per square inch. These values, however, are illustrative and do not imply any limit to the pressure which may be imposed or the strength of the shell.

The liner 15, providing internal flexible walls for the pressure chamber, is a sac or bladder made, preferably, of so-called synthetic or artificial rubber, which is impervious to liquids and is not injuriously 'ailected by oil. It is preferably molded with the same shape and dimensions externally as the interior of the metal shell, so that, when placed in the shell, it will fit smoothly therein and bear evenly on the internal surfaces of the shell, when distended without being materially stretched. In the form shown in Fig. 3, it is provided at its opposite ends with tubular extensions IB and H which pass through nipples on the ends of the shell and the bores of which communicate with the interior space of the sac. Any suitable packing or sealing means, of known character, not necessary to be shown here, may be provided to prevent leakage of the working fluid from the shell around the said extension tubes. The extension it is connected with the inlet pipe ll of the tank through a check valve I8 and the extension ii is connected with the source pipe [3 through a check'valve la; these check valves being arranged to permit how of water from the source into the compression chamber and from the compression chamber into the tank, and prevent return flow of the water.

A variant of the pressure chamber or accumulator previously described, is shown in Fig. 1a, wherein the rigid shell MI is a sphere and the flexible walled sac or liner is likewise a sphere and is made with an external diameter substantially equal to the internal diameter of the shell so as to fit therein and fill the shell when distended without being materially stretched. This sac or liner is made with a single opening from which an extension tube 553 leads and is connected by a T connection with the supply pipe i3 and delivery pipe l, in which check valves i9 and it are connected substantially the same manner and with the same effect as the check valves previously described.

Working fluid is delivered into the shell i l (01' Ml) between the walls thereof and the flexible walls of the sac by means of a pump 28 through a pipe 2 i, a direction control valve and a pipe 23 which is connected to the shell i i, is at any convenient point. The working fluid is a liquid which does not corrode iron or steel, preierably oil of good lubricating quality. A suliicient supply for the purpose is contained in a tank it. The pump is connected to take oil from the tank and discharge it through the pipe 2 I. This pump may be located in any convenient relationship to the tank and be connected with it in any suitable but preferably it is located in the tank and more or less submerged in the oil; at least to the extent that its intake is so submerge-cl. This arrangement simplifies the construction by eliminating some piping and the necessity for several fluid tight joints.

Pump 2c is here illustrated as a gear pump; but it should be understood that a pump of any other type, such as one having one or more reciprocating pistons or plungers, may be used. It is driven by an electric motor 25 located outside of the oil tank, the power shaft of which extends into the tank to connection with one of the pump gears or the power receiving element of wha ever other type of pump may be used.

The pump motor 25 is automatically controlled by the pressure in the water tank it so as to run when that pressure drops below a predetermined degree and to stop when the pressure is raised to that degree. I have here shown conventionally one or" the possible means by which the motor may be controlled, consisting of a switch 28 in the electric circuit of motor 25, which is normally closed by a spring 2?, and is opened by deflection of a diaphragm 28 under pressure of air in the tank is, conducted from the air space thereof through a pipe 29 to a chamber iii} in which the diaphragm is located. Diaphragm 23 is coupled with the movable member of the switch by a link 3E, and the spring is disposed to press on the diaphragm in opposition to the air pressure. It may be understood, without illustration, that the spring may be adjustable so as to regulate and vary the degrees of pressure at which the switch will be opened and closed.

The direction control valve 22 comprises a casing with which the pipes 2i and 23 are connected in tandem with an internal flow passage 33. There is also a return passage 34 in the ca ing, into one end of which a return pipe 35, branching from the pipe 23, enters and from the other end of which a discharge pipe 35 leads to the tank 24. Two cross passages 3i and 38 extend from the flow passage 33 across the return passage 34 to the outer side of the valve casing. A piston valve 39 is contained in the passage 37 and is pressed toward a seat 4!! therein by a spring 4| abutting against a screw plug 32, which is screwed into the outer end of this passage. A relief valve 43 is contained in the passage and is normally held against a seat @4- therein by a spring 45 which reacts against a screw plug 46. e

The piston valve 39 is of a length such that,

whenin contact with its seat 40 (in the position shown in'Fig. 2), it leaves-the return passage 34 open and,when. displaced to the right from the position shown, it crosses and blocks the return passage. Spring M is powerful. enough .to hold the piston valve in the position shown when the pump is not operating, but not to prevent its displacement .under the pressure. developed by the pump, and it yields to permit placement of the valve across the return passage 34 when the pump is'runningto force fluid through passage 33. In installations wherethe connection of the. return pipe .35'with the pipe 23 is high enough above the valve .22, the pressure head of working fluid in the pipe 23 is sufiicient todisplace the piston valve in .the manner described before the fluid reaches the return pipe. But to guard against any possibilityof obstructive back pressure being developed in the return pipe. 35 andpassa'ge 34 before. the piston valve has been thus. shifted, which might prevent shifting of the piston valve far enough to close the returnpassage, an obstruction or constriction'may be inserted'in the pipe 23 at any convenient pointzbelow itsijunction with the pipe 35. Such constrictions may be of any suitable character to impede free flow of the working fluid and, by way of illustration, I have shown one such constriction in Fig. 2 as a ring 33I set into the bore of pipe 23.

A stem 41, projecting from the valve 39. is disposed to abut on the screw plug 42 and arrest the valve in position to obstruct the return passage when so displaced. An entrapment relief passage 48 runs from a point in the outer part of the cross passage 3'! beyond the arrested position of valve 39, to the return passage 34 at a point between the two cross passages.

Spring 45, which bears on the relief valve 43, is powerful enough to hold that valve seated against displacement'under fluid pressure'of any'less intensity than that required to be maintained in the supply tank I0, but yields to permit relief of excess pressure.

The apparatus thus described operates in the following manner. Assuming that the tank I is filled to the prescribed point with water and the air cushion in the tank is at the prescribed maximum pressure, the automatic control switch is open. Then the pump is stationary and the accumulator chamber liner I5 is full of water. When the air pressure in the tank is reduced, due to withdrawal of water, the automatic control switch closes and the motor 25 is started. The pump 20 then forces oil into the accumulator shell, displacing the piston valve 39 so as to obstruct the return passage of the direction control valve 22, and squeezing the sac or liner of the accumulator. Pressure is thus-imposed on the water in the accumulator which, being confined-by the check valve l9, isthereby forced into thetank l0. Flow of water into the tank continues until the air pressure therein becomes great enough to open the control switch of the motor circuit, whereupon the pump is stopped. Valve piston 39 in the direction. control valve is then shifted by spring 4| to open the return passage 34 and the oil in the accumulator shell isallowed to flow back to the container 24; and the accumulator is again filled with water under the pressure of the source. This action is re-' peated whenever water is withdrawn from the supply tank, and thereby a continuous supply of water at substantially constant pressure is automatically maintained in the tank.

, The capacity of the accumulator is'made, great enough to transfer into the supply tank, with each operation, enough water to compress the air entrapped in the tank as much as may be needed to open the control switch. Initial filling of the tank may be accomplished by alternately starting and stopping the pump motor manually until-the desired pressure has been obtained. Imposition of too great-pressure is made impossible by the relief valve 43, which opens the bypass passage 38 from the pressure line 2| to the return line 36 when the pressure developed by the pump becomes excessive. 1

Evidently the apparatus precedently described, and equivalents thereof, can be used for imposing pressure on, and holding under a prescribed pressure head, other liquids than-Water, wherefore the references to water in the foregoing description are to be understood as illustrative and not limiting of the scope of the invention.

Other' means for controlling the direction of flow of the working fluid are within the scope of the'invention, one of which is shown in Fig-g4;

This embodiment is not dependent on initial pres sure at the source from which the water is derived for filling. the accumulator chamber with water,

but is capable of inducing flow into the chamber.- Here a reversible motor 25a is substituted for theing to the direction inwhich the pump is driven.

Withdrawal of the working fluid from the shell of course produces a vacuum effect which causes liquid to enter the accumulator. For instance, water can be taken from a well or from atank at a lower level than the accumulator to be stored under pressure in the tank I0.

Reversing means for the motor are indicated here as a reversing switch 50 and a pressure chamber 30 like that shown in Fig. 1, connected to actuate the switch. It may be understood without specific'illustration that any suitable means of known character may be applied by thedesigner of electrical equipment efiective to start the motor when the pressure head drops in the storage tank, operate the motor in reverse when the prescribed degree of pressure is attained, and stop the motor when the accumulator is filled by the suction eiiect of the pump. A torque motor may be used in this connection.

An alternative combination within the scope of the invention comprises two or more accumulator chambers with connections and direction control means organized to direct the pressure fluid to the several accumulators in turnso as to en-- able each to be refilled when the other, or others, are being discharged and to maintain an'unim terrupted delivery flow. An embodiment of this combination is illustrated in Fig. 5-. Twoaccumulator chambers, I4 and [4a, each having an inlet connection l3 with interposed check'valve [9, are connected through check valves I8 and 18a with a common'delivery pipe 5!. A pump 20 in a tank 24 containing oil is connected by a delivery pipe 2 lb with the casing of a four way valve from which connection pipes 23c and 23b lead to the accumulator chambers l4 and [4a, respectively. A return pipe 36a leads from the valve casing back to the tank 24. A- valve .ele-

ment 52 in the four way valve casing is provided with passages suitably related to the before named pipe connections to connect the pump delivery with the accumulator Ma and connect the accumulator [4 with the return pipe 36a when in the position shown in the drawing; to connect accumulator Hi with the pump and accumulator [4a. with the return pipe when rotated through an angle of 90, and to reverse these connections when turned through further steps of 90 each. Thus each accumulator may be filled with liquid while the other is being discharged.

It is desirable in some of the uses to which this equipment may be put that the direction control valve be shifted from each of its positions to the next as rapidly as possible so that there will be no appreciable interruption to the flow of liquid through the pipe I have shown here an illustrative means which accomplishes that result at definite intervals of time. The rotary valve element is rigidly connected with a ratchet 53 having four teeth, and a pawl 54 cooperating with the ratchet is carried by a pawl carrier 55, to which a pinion 56 is connected. An endwise movable rack bar 5'! meshes with the teeth of pinion 56 and is normally pressed by a spring 58 against an abutment 59. The pump driving motor is coupled to drive a worm 60 meshing with a worm wheel 6!, to which is connected a disk 62 having a tooth 63 disposed to engage a shoulder 64 on the rack bar in the course of its rotation. Tooth B3 and shoulder 54 are arranged to cause the rack bar to be shifted away from abutment 59, with compression of spring 53, in

the course of rotation of the disk 62, and to release the rack bar when the gear 56 has been rotated a quarter turn and enough more to carry the pawl 54 into engagement with the next succeeding tooth of the ratchet 53. Reaction of the spring when tooth 63 passes away from the shoulder 64, causes instantaneous rotation of the ratchet and valve cock through the angle needed to reverse the connections of the pump with the accumulator chambers.

This explanation of control means is illustrative of the principle rather than a limitation to specific means. Various other means within the competence of the skilled mechanic may be applied for effecting the same ends. The same principles may likewise be applied in combina tions of a pump with more than two accumulator chambers. The driving gear between the motor 25 and the disk 62, or equivalent initiator of valve displacement, may be designed to cause shifting of the valve after any desired number of revolutions of the pump gears or strokes of a pump of other type.

A common feature of all embodiments of this invention is the exclusion of the liquid on which pressure is imposed from the pump which develops the pressure, and the provision of a flexible wall or liner in a substantially rigid chamber as the means for effecting such exclusion. Thereby corrosion and abrasion of the pump parts by the liquid subjected to pressure, or by matter carried in suspension by the liquid, is prevented. In addition, wear due to rubbing of the parts of the pump on one another is substantially eliminated, or very greatly reduced, by the empioyment of a. good lubricant as the working fluid through which pressure is transmitted from the pump to the accumulator chamber. By running the pump in oil, an almost unlimited length of service is assured.

A secondary, but important, feature of the invention is the specific type of accumulator described herein, consisting of an inflexible shell and a highly flexible sac or liner substantially fitting the interior of the shell and having suitable connections for inflow and outflow of liquids. The sac is protected by the shell against danger of rupture, and it can be collapsed without harm by the working fluid to the extent that substantially all of the liquid contained within it is expelled. The form of accumulator shown in Fig. 1a, and its flow connections, can be used in any of the combinations represented in Figs. 1, 4 and 5, as well as the accumulators and connections there shown; and in other combinations also.

Another generic feature of the invention is direction control means by which working fluid is caused or allowed to flow into and out of the shell of the accumulator. This feature is shown here in three embodiments; the direction control valve 22, Figs. 1 and 2, the means for reversing the pump motor, exemplified by Fig. 4, and the reversing valve 52, exemplified by Fig. 5.

What I claim is:

1. An apparatus for imposing pressure on liquid comprising a pump, an accumulator having a substantially rigid shell and an interior flexible member dividing the shell into two spaces with inflow and outflow means for conducting liquid into and out of one of said spaces, a conduit between the pump and the other of said spaces, a container for working fluid with which the pump is in receiving connection, means for operating said pump to cause transfer of working fluid from the container to the second named space in the accumulator, and provisions for causing return flow of Working fluid from the last named space to the container.

2. An apparatus for imposing pressure on liquid comprising a pump, an accumulator having a substantially rigid shell and an interior flexible member dividing the shell into two spaces with check-valve-controlled flow means for conducting liquid into and out of one of said spaces, a conduit between the pump and the other of said spaces, a container for working fluid with which the pump is in receiving connection, means for operating said pump to cause transfer of working fluid from the container to the second named space in the accumulator, and valve means shiftable to eifect flow communication from the pump to the second named accumulator space and from such space to the fluid tank, respectively.

3. An apparatus for imposing pressure on liquid comprising a pump, an accumulator having a substantially rigid shell and an interior flexible member dividing the shell into two spaces with flow means for conducting liquid into and out of one of said spaces, a conduit between the pump and the other of said spaces, a container for working fluid with which the pump is in receiving connection, means for operating said pump to cause transfer of working fluid from the container to the second named space in the accumulator, and means for driving the pump reversibly whereby to propel working fluid into the second named space of the accumulator when the pump is driven in one direction, and to withdraw the fluid from such space when the pump is driven in the opposite direction.

4. An apparatus for maintaining a supply of liquid under augmented pressure comprising the combination of a tank, an accumulator connected to receive liquid from a source and deliver such liquid into the tank, said accumulator including an internal flexible element dividing its interior into a space in receiving connection with the source and delivering connection with the'tank, for the liquid on which pressure is to be imposed and a space for a workingrfluidg-a motor driven pump coupled with the last named spacefiof said accumulator for delivering working". fluid thereto, and means controlledby pressure'inthe tank for operating said pump to cause flow of working fluid into and out of such space.

5. An apparatus of the character described, comprising a liquid storage tank having an air space wherein air is compressed by accretions of liquid forced into the tank, combined with connections for flow of liquid leading to the tank including an accumulator having a flexible wall arranged to be moved by applied fluid pressure and to apply pressure to liquid in progress toward the tank when so moved, a container for a non-corrosive lubricant fluid, a pump connected to take fluid from said container and deliver it in pressure exerting contact with said flexible member, and control means for said pump operable by fluctuations in pressure head of the liquid in the tank to cause intermittent application by the pump of working fluid pressure against said flexible member.

6. The combination with a receiving tank of an accumulator having a rigid shell and a flexible wall sac in the shell, such sac having connecf tions with the tank to deliver liquid thereto and with a. source of liquid for receiving liquid therefrom, and being otherwise impervious to liquid, check valves in said connections disposed to prevent back flow of liquid from the tank to the sac and from the sac toward the source, a pump having receiving connection with a container of working fluid and delivering connection with the interior of said shell externally of said sac, and

control means operable by the internal pressure in said tank for causing the pump to force working fluid into the shell when the tank pressure diminishes below a predetermined degree and to cease so doing when the tank pressure rises above that degree.

7. The combination set forth in claim 6, in combination with means for releasing the pressure fluid from the shell when the pump ceases to force working fluid into the shell.

8. The combination set forth in claim 6, in T which the control means include means for reversing the directional action of the pump whereby the pump is caused to pass fluid into and out of the shell according tothe direction of its action.

9. The combination of a pump with a plurality of accumulator chambers, each such chamber having an interior flexible wall dividing its interior into a space for liquid to be operated on and a space for working fluid, means for conducting liquid into and out of the first of said spaces, a container for working fluid with which the pump is associated to take working fluid therefrom, flow connections including a selective valve between the pump and each of the accumulator chambers opening at the working fluid receiving side of the internal flexible element thereof, and means for shifting said valve to connect the pump with each accumulator in turn and to release working fluid from the other acelement displaceable to vary the volume of such space, a container for working fluid, a pump disposed to take fluid from said container, and a direction control device arranged to receive working fluid from the pump and deliver the same into the accumulator at the opposite side of said flexible wall from the liquid, holding space of the accumulator, said direction control device having a return flow passage and including valve means disposed to block said return passage when the pump is in operation and to open the passage when the pump is inactive.

11. An apparatus for imposing pressure on liquid comprising an accumulator shell of substantially inflexible construction, a flexible liquid-impervious sac in said shell, liquid conducting means connected with said sac for inflow and discharge of liquid, a container for working fluid, a pump disposed to take working fluid from said container, a direction control device having a passage coupled with the pump to receive fluid therefrom and coupled with the accumulator to deliver fluid thereinto externally of the sac, said direction control device having a return passage connected with the accumulator for permitting outflow of working fluid therefrom and having an internal valve element movable across and aside from said return passage and being exposed to pressure in the flow passage of the control device so as to be shifted by such pressure into obstructing relation to the return passage.

12. A directional flow control device for liquids comprising a casing having a flow passage and a return passage through it with provisions at both ends of each passage for connection with liquid conductors, the casing having also a cross passage communicating with both the flow and return passages, a valve element located in said cross passage in exposure tothe fluid pressure existing in the flow passage, arranged for movement from a position between the flow and return passages to a position in which it obstructs the flow passage, and a spring acting on said valve element with tendency to hold the element in the first named position and being yieldable to permit shifting of the valve element into the second named position when a fluid pressure is imposed in the flow passage sufficiently intense to overcome the force of the spring.

13. An apparatus of the character described, comprising a liquid storage tank having an air space wherein air is compressed by accretions of liquid forced into the tank, a pump for forcing liquid into said tank, and means for applying the force effect of the pump to such liquid and preventing direct contact of the liquid with the pump; said means comprising a shell, a flexible member contained in the shell arranged to divide the interior of the shell into non-communicating spaces, one of said spaces being connected to receive liquid from a source and to discharge liquid into the tank, a check valve arranged to prevent flow of liquid from said space toward the source, a check valve arranged to prevent back flow of liquid into said space from the tank, a flow connection for working fluid between the other of said spaces within the shell and the delivery side of the pump, and a container for Working fluid with which the other side of the pump is in flow connection.

14. The apparatus set forth in claim 13, combined with a driving motor connected with the pump for actuating it, and pressure controlled means for stopping and starting said motor connected with the air space in the tank to be actuated by varying pressures therein.

FREDERIC MCINTYRE.

REFERENCES CITED 5 Number 12 UNITED STATES PATENTS Name Date Northey July 6, 1886 Martin Oct. 1, 1940 Carpenter Nov. 5, 1940 Herman July 20, 1943 Teeter Apr. 25, 1944 Tannehill Dec. 3, 1946