US3905724A

US3905724A - Pneumatic pump

Info

Publication number: US3905724A
Application number: US440451A
Authority: US
Inventors: David W Strebel
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-02-07
Filing date: 1974-02-07
Publication date: 1975-09-16
Anticipated expiration: 1992-09-16

Abstract

A pneumatic pump comprising a vessel with inlet and outlet liquid ports. With a gas exhaust port open, the vessel is filled with the liquid in which it is immersed and a rising float operates a pilot valve to introduce a pressurized gas to a piston, driving it in one direction to close the gas exhaust port and uncover a gas charge port opening into the vessel whereby the gas forces the liquid from the vessel. A weight buoyed by the liquid in the vessel actuates the pilot valve in the other direction when the level falls to a predetermined low, closing the gas supply and venting the gas from the piston, enabling vessel gas pressure above the piston to drive the piston down first to close the gas charge port and then to open the exhaust port.

Description

United States Patent Strebel Sept. 16, 1975 PNEUMATIC PUMP [76] Inventor: David w. Strebel, 4380 Hall Rd., f

Sama Rosa Calif: 95401 ASSlStdlll Examiner-Leonard Smith Attorney, Agent, or FirmMelvin R. Stidham, Esq. [22] Filed: Feb. 7, 1974 21 Appl. No.: 440,451 [57] ABSTRACT A pneumatic pump comprising a vessel with inlet and outlet liquid ports. With a gas exhaust port open, the

[52] U.S. Cl.z 417/128; 417/133; 417/146 vessel is n with the liquid i which i i immersed [51] II.- Cl. .L F04F 1/06 and a rising float operates a pilot valve to introduce a [58] Fleld of Search 417/128, 133, 137, 146 pressurized gas to a piston, driving it in one direction to close the gas exhaust port and uncover a gas charge [56] 1 References Clted port opening into the vessel whereby the gas forces UNITED STATES PATENTS the liquid from the vessel. A weight buoyed by the liq- 533,22s 1/1895 Merrill 417/128 x uid in the vessel actuates the pilot valve in the other 1,213,707 1/1917 Swanstrom.. 417/128 X direction when the level falls to a predetermined low, 1,281,072 1918 g rs 7/ 8 X closing the gas supply and venting the gas from the 1,437,686 12/1922 sell" r r r 417/128 piston, enabling vessel gas pressure above the piston gogers Q to ive the piston down first to close the gas charge ogers.... 1,628,276 1927 Rogers 417/128 x port and to open the exhaust port 1,776,266 9/1930 McMillian 417/128 8 Claims, 6 Drawing Figures 2-74 L WL: 32 70 1mm;

' m s%tr 34 t I l P62 w l 64 :4 e 5' 1 BE PATENTEU I 5|975 3 905 724 FIGURE 3 FIGURE 2 PATENTEI] SEE I 6 i975 SQEET 3 BF 3 FIGURE 4 6 E R U W F FIGURE 5 PNEUMATIC PUMP BACKGROUND OF THE INVENTION There is a great demand, particularly among campers, hikers and the like for a pump which may be operated to deliver water from a source thereof in order to supplement fresh water being carried. In many camper vehicles, there is a storage vessel for a limited supply of drinking water. However, during extended stays away from a replenishing source, as during a protracted camping trip, it often becomes necessary to restrict the use of water other than for,drinking and cooking. Accordingly, it is highly desirable to have a supplementary source of water available for bathing, washing equipment and utensils, dousing camp fires and the like. Of course, when camping alongside a lake or stream, water is readily available for immersion or for carrying containers thereof. Still, however, it often is desirable to have water delivered to a site displaced from the lake or stream, such as to an improvised shower, or to a camp fire site for wetting down the area and/or dousing the fire.

OBJECTS OF THE INVENTION It is an object of this invention to provide a pneumatic pump which maybe immersed in a body of liquid to deliver streams thereof through a hose connected thereto.

It is a further object of this invention to provide a pump which may be immersed in a lake or stream to deliver water therefrom without requiring an electric motor or internal combusion engine.

It is a further object of this invention to provide an immersible pneumatic pump which is compact and portable and simple and reliable in operation.

It is a further object of this invention to provide an immersible pneumatic pump which realizes efficient use of the available compressed gas with a wide range of pressures.

It is a further object of this invention to provide an immersible pump which produces a rapid and complete liquid fill cycle.

It is a further object of this invention to provide a pair of pneumatic pumps with slave operation enabling them to be operated in tandem for constant liquid flow.

It is a further object of this invention to provide a pneumatic pump which is simple and inexpensive to manufacture and service, but reliable in operation.

Other objects and advantages of this invention will become apparent from the description to follow when read in conjunction with the accompanying drawings.

BRIEF SUMMARY OF THE INVENTION In carrying out this invention, there is provided a vessel which is adapted to be immersed in a body ofliquid whereby, when not under gas pressure, the vessel is filled by the liquid in which it is immersed. A rising float in the liquid operates an over-center mechanism to provide snap-action of a pilot valve. The pilot valve when so operated, closes a cylinder in the valve block to a vent passage and opens it to a gas supply. The gas drives the piston against a spring to close a large capacity exhaust port, sealing off the main vessel, and opening a large capacity gas charge port delivering the gas supply to the vessel, The gas supply then commences to drive the liquid out through a one-way checkvalve outlet until it reaches a predetermined low level wherein a weight of a material of approximately the specific gravity of the liquid, which is normally buoyed by the liquid, is suspended with the unsupported weight sufficient to overcome the spring-loaded over-center mechanism, pulling it back down to move the pilot valve in the opposite direction. This closes the servo cylinder to the gas supply and opens it to the atmosphere in a primary exhaust, whereby the vessel gas pressure above the piston forces it back down to close off the gas charge port and then open the vessel exhaust port, allowing the liquid once again to fill the vessel and further exhaust the gas.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical section view of a pneumatic pump embodying features of this invention;

FIG. 2 is an enlarged partial section showing particularly the gas valve operating means;

FIG. 3 is a section view taken along Lines 33 of FIG. 2;

FIGS. 4 and 5 are enlarged partial section views showing the gas valve mechanism in different stages of operation; and

FIG. 6 is an enlarged section view of a slave mechanism constituting a feature of this invention.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2 with greater particularity, the pneumatic pump 10 of this invention comprises a main pump vessel or chamber 12 on which may be carried an optional pump volume tank 14 of a predetermined volume. The pump volume tank may be mounted by simply sliding it over the vessel with suit able seals, such as O-rings l6 sealing around the ends of the volume tank 14. The pump volume tank 14 may be of selected sizes and shapes but, in all cases the top of it should not be above the operating level of the float to be described. In any event, when the pump volume tank 14 is applied, a series of ports 18 in the wall of the main pump vessel 12 are unplugged to provide for free flow of liquids and gases between the pump vessel and the volume tank. In any event, the pump 10 is adapted to be immersed in a body of liquid W, as for example, a lake or river to a level W.L. at least to the top of the pump chamber 12 to insure filling of the chamber and volume tank under liquid pressure head.

At the bottom of the pump vessel 12 there is provided a large capacity, liquid intake check valve assembly 20, which allows free entry of the liquid into the chamber to its own level or until the vessel is gas charged, as hereinafter described. As in cases when the liquid is water to be delivered from a lake or stream, a liquid screen and sand baffle 22 may be provided around ports 24 in the depending skirt 12a of the pump vessel to preclude entry of sand and debris. Weights 26 may be carried at the bottom of the skirt 12a to stabilize the pump 10 in the body of liquid W.

Opening from a lower level of the pump chamber 12 is a pump liquid discharge check valve assembly 28 which enables discharge of liquid under gas pressure, as will be described, but precludes the entry of liquid into the pump chamber therethrough. A suitable line 29, such as a hose or the like with a shutoff valve 29a therein, may be attached to the discharge check valve assembly 28.

Mounted on the top of the pump chamber 12 is a gas charge and valve mechanism 30 which is operated under control of a pressure balanced, low capacity pilot valve 32. As will hereinafter be described in greater de' tail, when the pilot valve 32 is moved down to the position shown in FIG. 1, the pump chamber 12 is exhausted of gas and allowed to fill with liquid. When it.

is moved to its upper position, the pump chamber is charged with gas froma suitable source 33 such as a compressor, gas bottle-or the like, through a pressure regulator 33a, if desired,.to force discharge of liquid through the outlet 28.

Pivotally carried at opposite sides of the pump chamber near the top thereof is an over-center mechanism 34 including a pilot control arm 36 and a spring loaded arm 38 carrying inwardly directed pins 40 (FIG. 3) which bear against spaced

collars

42 and 44 on the pilot valve 32. The spaced

collars

42 and 44 enable some pivotal movement of the pilot control arm 36 without moving the pilot valve 32. Then, when the midway position of the over-center mechanism is reached, the spring loaded arm 38 will drive the mechanism through its full stroke for snap-action operation of the pilot valve. The upper collar 44 engages the undersurface 46 of a servo valve block 48 to define the upper position of the pilot valve 32. A stop collar 50 on the upper end of the pilot valve 32 engages the servo block upper surfac e 51 to define the lower positionshown in FIGS. land 2. The servo block cover 52 is secured to the servo block 48 and the main vessel 12 by any suitable means such as cap screws 53 (FIG. 4).

Extending over the top of the over-center mechanism 34 isa rod loop 54 carrying a weight cup 56 at its lower ends so that, when the tank is substantially empty, it pulls-the over-center'mechanism down to the position shown in FIG. 1. The weight 56 is made of a suitable material-which is substantially of the specific gravity of the liquid so that, immersed in the liquid, it provides very little downward pull on the mechanism, insufficient to overcome the spring loaded arm 38. However, when the tank empties, leaving the weight unsupported, it is heavy enough to pull the over-center mechanism down to the position shown in FlGS.-l and 2. With aweight cup configuration, the weight is augmented-by the weight of a-quantity of water in the suspended cup. ''As the tank 12 fills, liquid enters the weight cup 56 through ports 58 so that it still has no effect on the overcenter mechanism 34. Even should it become relatively buoyant, the rod loop 54 would simply'tend to rise above the over-center mechanism and produce no action'thereof. However, as the tank empties, the water flows out of the weight cup 56 throughthe-ports 58 leaving a relatively small amount of liquid at the bottom of the bowl. It is only when the level of liquid in the cup can overcome the over-center spring 38 that the'pilot valve 32 is pulled down to the position shown in FIGS. I and 2. Hence, the main vessel 12 is almost completely emptied before the refill cycle commences.

Immediately below the over-center mechanism 34 is a float 60, preferably of the inverted cup type. The float is carried within a guide and baffle chamber 62 having a plurality of orifices 64 through which the weight cup support and actuating rods 54 extend. The orifices retard entry of fluid into the float chamber to insure maximum filling of the pump tank 12 before the float becomes buoyant. As previously described, the spacing of the

collars

42 and 44 on the pilot valve 32'enable some flotation of the float 60 until the over-center mecha nism is moved by engagement ofipush bars 66 on the top of the float with a cross rod 67 at the pivot point of the mechanism 34, substantially to its halfway point before the pilot valve is operated. Just as some buoyancy of the weight cup 56 has no :effect on the overcenter mechanism, dropping ofthe float merely causes it to fall away from the linkage. The float 60 and the weight 56 each operate the linkage in only one direction, the float 60 to push it up and the weight 56 to pull it down;

Referring now to FIG. 4, when the pilot valve 32 is moved to its upper position shown therein, the primary exhaust port 68 is closed off and gas is permitted to flow from the gas inlet 70 and through the servo load duct 71 in the servo block 48 around the pump charge valve 72, which depends from a servo piston 74. In the position shown in FIG. 4, the pump charge valve closes off the port 76 opening into the pump chamber 12, but the gasmay flow around it and through the pilot valve flow passage 80 to the intake port 82 of the servo cylinder 84 in which the-piston 74 is slidably carried. The pressure in the cylinder overcomes the spring 86 carried between the piston 74 and a muffler cover 88 and forces the piston 74 upward to the position shown in FIG. 5 wherein sealing means 90 on a pump exhaust valve 92 carried on th'e'piston 74 enters into the 'vessel exhaust port94 and precludes further exhuast of the pump chamber. After the vessel exhaust port is closed off, the pump charge valve 72 carried on the other side of the piston 74 clears the pump charge port 76 and flow from the gas inlet 70 is directed into the main pump chamber 12 to force the liquid therein out through the water discharge port 28 (FIGQl).

Water discharge continues until outlet valve 29a is closed or until the main pump chamber 12 is nearly emptied, at which time the weight cup 56 is suspended with a quantity of liquid sufficient to overcome the spring loaded over-center mechanism 34 and commences to pull it down. Again the clearance between the

pilot valve collars

42 and 44 permits some free movement of the weight without actually actuating the pilot valve until the over-center mechanism reaches approximately its midpoint. This insures maximum water discharge. Then, the pilot valve is snapped down into the position shown in FIGS. I and 2. In this position, the pilot valve 32 closes off the servo cylinder port 82 to the gas inlet 70 and opens it to the exhaust port 68 to commence the primary exhaust. If desired, the rate of exhaust may be pre-adjusted by a control screw 98. In anyevent, when the servo cylinder 84 is exhausted to the pointthat the pressure of vessel gas below the servo cover 52 overcomes the exhausted gas pressure below the piston 74, the pump exhaust valve 92 is moved to the position shown in FIG. 2 wherein the exhaust port 94 isopen. Hence, the secondary exhaust commences and gas in the main vessel 12 is evacuated through vent passages formed in the servo block 48, and out through the main exhaust port 94. The spring 86 holds the piston in the retracted position. This secondary evacuation of gases continues in this manner as the'liquid fills the chamber and the float 60 ultimately moves the pilot valve upward again to the position shown in FIG. 4. The exhaust cycle finally terminates when the piston 74 reaches the position shown in FIG. 5. The muffler 88 (FIG. I) diverts the gas stream to silence the exhaust and also covers the otherwise exposed servo piston 74."

As an optionalfeature of this. invention, the servo block covert52 may be' drilled and tapped at 106 (FIGS. 1 and6) to accommodate a slave cylinder 108 which enables operation of two of my pneumatic pumps 10 in tandem, through a single source 33 of gas pressure. A slave control duct 110 opens into the servo cylinder 84 of each pump 10 and is brought into communications with the cylinder head port 112 to operate the slave piston 114 of the otherpump. Hence; a servo cylinder 84 under pressure is the master, and the pressurized gas therein will force the slave piston 114 of the other down against itsspring 116 to hold the pilot valve 32 of the slave pump 10 in its lower-position, shown in FIG. 1, even though the pump chamber 12 may be completely filled. Then, when the servo cylinder 84 of the master pump is evacuated as previously described, the slave cylinder 108 is also evacuated, and its spring 116 overcomes the slave piston 1 l4 and allows the pilot valve 32 to snap into its chargingposition shown in FIG. 4. This pump then becomes the master and its slave control duct 110 pressurizes the slave cylinder 108 on the other pump, holding its piston 114 depressed until the second pump servo piston is evacuated.

While this invention has been described in conjunction with a preferred embodiment thereof, it is obvious that modifications and changes therein may be made by those skilled in the art without departing from the spirit and scope of this invention.

1 claim:

1. In a pneumatic pump comprising:

a vessel adapted to be immersed in a body of liquid;

liquid inlet and outlet one-way check ports near the bottom of said vessel; and

gas valve means for discharging liquid from said vessel comprising:

a servo valve body;

a gas exhaust port in said body connected between said vessel and a zone at low pressure;

a gas charge port in said body in alignment with said exhaust port and connected between the interior of said vessel and a source of pressurized gas;

an exhaust stop valve and a charge stop valve operative to close said gas exhaust and charge ports, respectively;

a gas chamber in said valve body;

a gas pressure-responsive member mounted in said chamber for movement therein in opposite directions;

said exhaust and charge stop valves being carried on said pressure-responsive member and movable together therewith, said stop valves being so disposed that a force on one side of said pressure-responsive member moves said exhaust and charge stop valves together to close said exhaust port and open said charge port and a force on the other side of said pressure-responsive member moves said stop valves together to open said exhaust port and close said charge port;

a load vent duct opening into said chamber on said one side of the pressure-responsive member;

biasing means of said other side of said pressureresponsive member;

a primary vent duct connecting said load-vent duct to a low pressure zone;

a gas load duct adapted to be connected to a source of pressurized gas;

a pilot valve flow passage connecting said gas load duct and said primary vent duct'to said load-vent duct; I

a two-position pilot' valve movablejin said valve flow passage betweenone position wherein it blocks the connection between said load-ventduct and said primary vent ductfand the other position wherein it blocks the connection between said loadvent duct and said gas load duct; and

means operative when liquid in said vessel reaches a predetermined'high level *to move said pilot valve to said one position and means operative when liquid in said vessel reaches a predetermined low level to move said pilot valve to said other position.

2. In the pneumatic pump defined by claim 1 wherein:

said exhaust and charge stop valves'are carried on opposite sides of said pressure-responsive member;

said stop valves are relatively dimensioned so that sealing contact of said charge stop valve and said gas charge port is retained until after sealing contact of said exhaust stop valve and said exhaust port is established when said one side of the pressure-responsive member is exposed to a pressurized-responsive member is exposed to a pressurized gas.

3. In the pneumatic pump defined by claim 1 including:

means sealing said pilot valve and valve flow passage from said vessel.

4. In the pneumatic pump defined by claim 1 wherein the two last-named means comprise:

a float in said vessel adapted to move said pilot valve to said one position at said predetermined high level; and

a weight cup in said vessel adapted to move said pilot valve to said other position at said predetermined low level.

5. In the pneumatic pump defined by claim 4 including:

a spring loaded over-center device pivotally mounted in said vessel;

spaced members on said pilot valve engagable by said over-center device and moved thereby between said one position and said other position in response to pivotal movement thereof;

portions on said float engaging said device to spring it upward and move said pilot valve to said one position; and

means suspending said weight cup from said overcenter device.

6. in combination with the pneumatic pump defined by claim 4, a second pneumatic pump as defined thereby, and including:

a slave cylinder on each of said pneumatic pumps;

a piston slidable in said cylinder and disposed to en gage the pilot valve in said second pneumatic P p a port in said slave cylinder disposed so that pressurized gas therein forces said piston in one direction against said pilot valve to hold said pilot valve in said other position;

means biasing said piston in the other direction to free said slide valve; and

duct means connecting said slave cylinder port to the gas chamber of the other pneumatic pump.

7 7. [n the pneumatic pump defined by claim 1 whercinz said pilot valve isa rod movable axially in said valve flow passage; and including: first and second seal means in said valve flow passage between said load-ventduct and said primaryvent duct and betweensaid load-vent ductand said gas load duct, respectively; and i a sealing portion on said rod in sealing engagement with said first seal means in said one position and with said second seal-means in said other position. 8. In the pneumatic pump defined by claim 7 including: s

spaced collars on said pilot valve rod;

a spring load over-center arm pivotally mounted in only when not buoyed by fluid in said vessel.

Claims

1. In a pneumatic pump comprising: a vessel adapted to be immersed in a body of liquid; liquid inlet and outlet one-way check ports near the bottom of said vessel; and gas valve means for discharging liquid from said vessel comprising: a servo valve body; a gas exhaust port in said body connected between said vessel and a zone at low pressure; a gas charge port in said body in alignment with said exhaust port and connected between the interior of said vessel and a source of pressurized gas; an exhaust stop valve and a charge stop valve operative to close said gas exhaust and charge ports, respectively; a gas chamber in said valve body; a gas pressure-responsive member mounted in said chamber for movement therein in opposite directions; said exhaust and charge stop valves being carried on said pressure-responsive member and movable together therewith, said stop valves being so disposed that a force on one side of said pressure-responsive member moves said exhaust and charge stop valves together to close said exhaust port and open said charge port and a force on the other side of said pressure-responsive member moves said stop valves together to open said exhaust port and close said charge port; a load vent duct opening into said chamber on said one side of the pressure-responsive member; biasing means of said other side of said pressure-responsive member; a primary vent duct connecting said load-vent duct to a low pressure zone; a gas load duct adapted to be connected to a source of pressurized gas; a pilot valve flow passage connecting said gas load duct and said primary vent duct to said load-vent duct; a two-position pilot valve movable in said valve flow passage between one position wherein it blocks the connection between said load-vent duct and said primary vent duct, and the other position wherein it blocks the connection between said loadvent duct and said gas load duct; and means operative when liquid in said vessel reaches a predetermined high level to move said pilot valve to said one position and means operative when liquid in said vessel reaches a predetermined low level to move said pilot valve to said other position.

2. In the pneumatic pump defined by claim 1 wherein: said exhaust and charge stop valves are carried on opposite sides of said pressure-responsive member; said stop valves are relatively dimensioned so that sealing contact of said charge stop valve and said gas charge port is retained until after sealing contact of said exhaust stop valve and said exhaust port is established when said one side of the pressure-responsive member is exposed to a pressurized-responsive member is exposed to a pressurized gas.

3. In the pneumatic pump defined by claim 1 including: means sealing said pilot valve and valve flow passage from said vessel.

4. In the pneumatic pump defined by claim 1 wherein the two last-named means comprise: a float in said vessel adapted to move said pilot valve to said one position at said predetermined high level; and a weight cup in said vessel adapted to move said pilot valve to said other position at said predetermined low level.

5. In the pneumatic pump defined by claim 4 including: a spring loaded over-center device pivotally mounted in said vessel; spaced members on said pilot valve engagable by said over-center device and moved thereby between said one position and said other position in response to pivotal movement thereof; portions on said float engaging said device to spring it upward and move said pilot valve to said one position; and means suspending said weight cup from said over-center device.

6. In combination with the pneumatic pump defined by claim 4, a second pneumatic pump as defined thereby, and including: a slave cylinder on each of said pneumatic pumps; a piston slidable in said cylinder and disposed to engage the pilot valve in said second pneumatic pump; a port in said slave cylinder disposed so that pressurized gas therein forces said piston in one direction against said pilot valve to hold said pilot valve in said other position; means biasing said piston in the other direction to free said slide valve; and duct means connecting said slave cylinder port to the gas chamber of the other pneumatic pump.

7. In the pneumatic pump defined by claim 1 wherein: said pilot valve is a rod movable axially in said valve flow passage; and including: first and second seal means in said valve flow passage between said load-vent duct and said primary vent duct and between said load-vent duct and said gas load duct, respectively; and a sealing portion on said rod in sealing engagement with said first seal means in said one position and with said second seal means in said other position.

8. In the pneumatic pump defined by claim 7 including: spaced collars on said pilot valve rod; a spring load over-center arm pivotally mounted in said vessel and extending between said collars; said collars being engagable by said over-center arm and moved thereby between said one position and said other position in response to pivotal movement thereof; a float in said vessel; said over-center arm being in the vertical path of movement of said float to be moved thereby to said one position; and a weight in said vessel suspended from said over-center arm of sufficient mass to pull said arm down only when not buoyed by fluid in said vessel.