US2557724A - Air charger for hydropneumatic systems - Google Patents

Description

June 19, 195] w, BURKS 2,557,724

AIR CHARGER FOR HYDROPNEUMATIC SYSTEMS Original Filed March 9, 1945' UIIID I EL 2155 Patented June 19, 1951 AIR CHARGER FOR HY DROPNEUMATIC SYSTEMS Arthur W. Burks, Decatur,

Ill., assignor to Decatur Pump Company, Decatur, 111., a, corporation of Illinois Original application March 9, 1945, Serial No.

581,829. Divided and this application April 28, 1949, Serial No. 90,066

6 Claims.

The present invention relates to an air charger for hydro-pneumatic systems, and more particularly to an air charger for supplying air to a hydro-pneumatic tank in response to the pneumatic pressure requirements of the system.

This application is a division of my earlier filed copending United States application for patent, Serial No. 581,829, filed March 9, 1945, now U. S. Patent No. 2,509,130, issued May 23, 1950.

The present invention relates to a novel and improved air charger mechanism for maintaining the pneumatic pressures in a hydro-pneumatic supply tank within the desired limits. The air charger of my invention operates to supply air to the hydro-pneumatic tank if required whenever the pump that supplies the hydro-pneumatic tank with water is operated.

An important feature of my invention is the provision of a Venturi-type eductor, or aspirator,

operated by a flow of water under pressure from the pump, when the air cushion in the tank re-- quires replenishing, to draw atmospheric air into the air charger casing for subsequent displacement into the hydro-pneumatic tank to replace losses of air from the tank and to build up the air pressure therein to within the desired limits. A float valve cooperates with the eductor, or aspirator, to eliminate, or at least reduce, the possibility of air drawn in by the eductor finding its way into the pump and causing the pump to become air bound. This has been one of the objections to previous hydro-pneumatic systems employing means, such as an eductor, aspirator, or Venturi nozzle, to draw air into the system under the action of the pump.

The air charger of my invention acts each time that the pump is started up, if the water level in the hydro-pneumatic tank is below its normal level, to introduce a charge of air into the tank. If no air is required in the hydropneumatic tank, no new charge of air is delivered into the tank, but air is merely withdrawn from the tank and expelled back thereinto. The device is thus full automatic and requires little, if any, attention.

It is, therefore, an important object of this invention to provide an automatically operating air charger for maintaining the desired pneumatic pressure Within a hydro-pneumatic tank of a water supply system, the air charger being responsive to the pumping operation when the level of the Water in the tank is above normal to introduce a charge of air into the hydro-pneumatic tank. The air charger includes a Venturitype eductor, or aspirator, for aspirating air into the system and a float controlled valve on the suction side of the pump for eliminating or reducing the possibility of such air being drawn into the pump to thereby lessen its efficiency.

It is a further important, object of this invention to provide an air charger, the operation of which depends upon the action of an eductor, or aspirator, actuated by the pressure discharge of water from the pump, in combination with a float controlled valve on the suction side of the pump to reduce the possibility of air getting back into the suction line and destroying the prime of the pump.

It is a still further important object of this invention to provide an air charger which, in addition to its function of maintaining the desired pneumatic pressure in a hydro-pneumatic tank, is so arranged and positioned as to serve as a prime for the pump, supplying the hydro-pneumatic tank. 7

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawmgs.

On the drawings the single figure is a fragmentary, broken sectional view partly in elevation, of an air charger embodying the principles I of my invention.

As shown on the drawing:

The reference numeral I0 refers generally to a hydro-pneumatic tank, which, as is customary, is partially filled with water maintained under the pressure of an air cushion above the water level. Water is supplied to the hydro-pneumatic tank ID by a pump ll, preferably of the centrifugal type, which is connected through a suction intake pipe l2 leading through a foot valve I3 and a strainer I 4 to a water supply pipe [5. The pump II is directly connected to the bottom of the tank l0 through a discharge pipe [6,

An air charger indicated generally by the reference numeral I1 is connected by a pipe l8 to the pump discharge l6 through a fitting I9, which is in controlled communication through a port 20 with the intake side of the pump above the foot valve l3. Said air charger I1 is also connected at its top by means of a pipe 2| through a check valve fitting 22 to the tank In at or about its normal water level, as indicated by the dot-dash line N. The fitting 22 is provided with an enlarged bore 23 opening at its inner end into the tank It) and its outer end merging into a reduced bore 24. A conical ball seat 25 is formed between the enlarged and reduced bores 23 and 24, respectively, and a ball 26 is positioned in the enlarged bore 23 for the purpose of seating against the conical seat 25 and closing off the reduced bore 24 under certain conditions. A stop 21 prevents the ball 28 from becoming displaced entirely from the bore 23.

This arrangement of the ball valve fitting 22 is such as to permit flow of air through the fitting in either direction, but prevents the flow of water from the tank through the fitting into the conduit 2|. The latter is prevented by reason of the fact that the ball 28, in response to a flow of water from the tank through the fitting 22, rises against and seats upon the seat 25, thus closing off the reduced bore 24.

The air charger 11 provides a float chamber 28 in which is positioned a 30 attached thereto by stem 3i for controlling the port 20. The stem 3| passes freely through an apertured plug 32 in the upper wall 33 of the fitting I9. The apertured plug 32 thus provides a guide for the valve stem 3 l.

The air charger I1 is further provided with an offset upper chamber 34, in the lower wall of which is positioned an air intake valve 35. The air valve 35 includes a plug 36 having a small diameter bore 31 extending therethrough and terminating at its other end in a counterbore for receiving a resilient seat 38. A ball valve 39 normally seats upon the seat 38. The valve 39 has a stem 40 passing through the bore 31 and terminating in an enlarged head 4| that projects beyond the plug 36.

The fitting l9 houses a Venturi-type eductor 42 having an intake nozzle 43 for receiving water under pressure through the pipe l8 connected to the discharge pipe H; of the pump II and a discharge nozzle 44 opening into the interior 45 of the fitting IS. The eductor 42 is provided with an apertured, constricted throat 46 which is in communication with the float chamber 28 through a passage 41 in the upper wall of the fitting IS. The operation of the air charger illustrated in Figure 2 will now be explained.

When the pump II is started, assuming the water level in the tank I!) to be at or above the normal water level N, for instance, at the level indicated by the reference character H, the ball check fitting 22 prevents the flow of water through the piping 2! into the air charger H. The float chamber 28 is, however, filled with water from the end of the previous cycle. Accordingly, the float 29 holds the valve 30 oil of its seat 20 to permit the water in the float chamber 28 toserve as a primefor the pump ll. As soon as the pump starts pumping, it creates a sufficient suction in the intake l2 to open the foot valve l3 and draw in water through the intake supply pipe IS.

The water discharged from the pump through the discharge pipe 16 flows partly into the tank In and partly through the piping l8 into the eductor 42. The reduced pressure at the throat 46 of the eductor 42 causes water to be drawn from the float chamber 28 through the opening 41, thus lowering the water level within the float chamber 28 and effecting a reduction in the pressure above the water. Such reduction in pressure causes the air intake valve 35 to open and air to be drawn into the offset chamber 34.

When the water level in the float chamber 28 had dropped sufliciently to allow the float control valve 29 to close the port 29, the continued flow of water through the eductor 42 now flows through the throat aperture 43, through the opening 4'! and into the float chamber 28. The continued flow of water into the float chamber float 29 having a valve 28 effects the displacement of the air therefrom into the tank It; through the piping 2i and the ball check valve fitting 22. The float valve 23 remains seated because of the difference in pressure between that in the float chamber 28 and that in the pump intake piping !2. Water continues to flow from the throat of the eductor into the chamber 28 until'pressures are balanced within the float chamber 23 and the tank It, after which flow through the eductor ceases.

As soon as the pump stops, the foot valve 53 closes and pressure is equalized between the tank and the suction side of the pump through the pump itself, thereby permitting the float 29 again to rise and open the port 20. The charger is now ready to repeat the cycle when the pump again starts up.

If, however, the water level in the tank in slow the normal water level, as for instance, at the level indicated by the dot-dash line L, air is preferentially drawn in through the check valve fitting 22 and the piping 2| into the float chamber 28 and no atmospheric air is taken in through the air intake valve 35. The air so taken into the float chamber 28 is displaced back into the tank l0 whenever the chamber 28 fills with water, as when the pump stops or the valve 36 is seated. However, no atmospheric air is introduced into the tank l8 when the water level is below the normal water level.

f'hus, only when the pressure demand of the hydro-pneumatic tank In requires it is atmospheric air introduced into the tank through the air intake valve assembly 35.

It will thus be readily appreciated that the present invention contemplates the employment of a Venturi-type eductor for drawing in at mospheric air when the water level in the tan is at or above the normal level, and the use of a float valve for controlling the flow of water from the air charger to the intake side of the pump so that the eductor can operate when the pump is operating to draw a flow charge of air into the charger and subsequently effect the displacement of such air into the hydro-pneumatic tank. Also, the air charger serves as a prime for the pump because of its being positioned above the intake of the pump and because of the arrangement whereby pressures equalize themselves Within the air charger and within the hydropneumatic tank and the air charger fills up with water upon the pump being stopped.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. In a hydro-pneumatic system including a hydro-pneumatic tank and a pump for supplymg water to the tank through a discharge line, an air charger for supplying air to the tank in accordance with the level of water therein as maintained by the pump, said charger comprising a casing having an opening, a valve-con-- trolled connection from said opening to the tank at about the normal water level therein to permit air flow through the opening in either direction and water flow therethrough only in the direction of the tank, said casing having a fluid flow opening for connection to the suction side of the pump, a valve-controlled air intake for admitting atmospheric air into said casing, an

aspirator having an inlet connected to the pump discharge line and an outlet in flow communication with the pump intake line through said fluid flow opening for connection to the suction side of the pump, said aspirator having a conopening for connection to the suction side of the pump controlled by afloat in said casing, said valve being interposed between the discharge of said aspirator and the pump intake line, whereby provided the water level of the tank is above said normal water level, when the pump is started up, said float-controlled valve being at that time open, a flow of water under pressure through said aspirator draws atmospheric air through said intake for introduction into the casing and subsequent displacement therefrom into the tank through the valve-controlled connection to the tank upon the further flow of water into said aspirator and through the vent in the throat portion into said casing.

2. In a hydro-pneumatic system including a hydro-pneumatic tank and a pump for supplying Water to the tank, an air charger for supplying air to the tank in accordance with the level of Water therein as maintained by the pump, said charger comprising a casing, a valve-controlled connection from the casing to the tank at about the normal water level therein, the connection permitting air flow therethrough in either direction and Water flow only in the direction of the tank, said casing having a fluid flow opening for connection to the suction side of the pump, a valve-controlled air intake for admitting atmospheric air into said casing, an aspirator receiving water under pressure directly from said pump and discharging water into the intake side of said pump through said fluid flow opening for connection to the suction side of the pump and having a constricted throat portion vented directly to the interior of said casing for withdrawing water from said casing and drawing air into said casing upon the flow of water through said aspirator, and a float-controlled valve controlling said opening for connection to the suc tion side of the pump controlled by a float in said casing.

3. In a hydro-pneumatic system including a hydro-pneumatic tank and a pump supplying water to the tank, an air charger for supplying air to the tank in accordance with the level of water therein as maintained by said pump, said charger comprising a casing, a valve-controlled connection from the casing to the tank at about the normal water level therein, the connection permitting air flow therethrough in either direction and water flow only in the direction of the tank, said casing having a fluid flow opening for connection to the suction side of the pump, a valve-controlled air intake for admitting atmospheric air into said casing, a Venturi-type aspirator receiving water under pressure directly from said pump and discharging water into the intake side of said pump through said fluid flow opening for connection to the suction side of the pump and having a constricted throat portion vented directly to the interior of said casing, and a float-controlled valve interposed between the discharge of the aspirator and the suction side of the pump controlling fluid flow through said opening for connection to the suction side of the pump Said valve being controlled by a float in said casing, said aspirator functioning, upon said float-controlled valve being open, to withdraw water from said casing and draw air into said casing and said aspirator functioning upon continued water flow therethrough and the closing of said float-controlled valve, to introduce water through its vented throat portion into the interior of said casing to displace air into said tank through said valve-controlled connection thereto.

4. In a hydro-pneumatic system including a hydro-pneumatic tank and a pump for supplying Water to the tank through a discharge line, an air charger for supplying air to. the tank in ac cordance with the water level therein as maintained by said pump, said charger comprising a casing having a first opening, a valve-controlled connection from the first opening to the tank at about the normal water level therein, the valve-controlled connection permitting air flow therethrough in either direction of water flow only in the direction of said tank, said casing having a second fluid flow opening for connection to the pump intake, a valve-controlled air intake for admitting atmospheric air into the casing, an aspirator having an inlet receiving water directly from the discharge line of the pump and an outlet discharging water into the suction side of the pump through said second fluid flow opening, said aspirator also having a constricted throat portion vented directly into the interior of said casing to cause atmospheric air to be drawn into the casing upon water flow therethrough, a float-controlled valve in said second fluid opening for controlling discharge of Water from the aspirator into the intake side of the pump and a float in said casing for controlling said float-controlled valve, said casing being above the pump intake to provide a source of priming water for the pump.

5. In a hydro-pneumatic system including a hydro-pneumatic tank and a pump for supplying water to the tank through a discharge line, an air charger for supplying air to the tank in accordance with the water level therein as main tained by the pump, said charger comprising a casing having a first fluid flow opening, a valvecontrolled connection from said first opening to the tank at about the normal water level therein permitting air flow therethrough in either direction and water flow only in the direction of the tank, said casing having a second flu flow opening for connection to the intake side of the pump, a valve controlled air intake, an aspirator connected directly to the discharge line of the pump and discharging into said casing adjacent said second flow opening, said aspirator having its low pressure throat zone vented in direct flow communication with the interior of said casing, and a float-controlled valve in said second fluid flow opening with its float in said casing, whereby fluid flow through said aspirator will withdraw water from the interior of said casing when said float-controlled valve is open, thus opening said air intake to replace water removed from the casing with air and continued flow of water through the vented throat of said aspirator when said valve is closed refilling the casing with water and displacing air therefrom into the tank.

6. In a hydro-pneumatic system including a hydro-pneumatic tank, a pump for supplying water thereto, and a water supply pipe to said pump having a foot valve therein, an air charger having a first fluid flow opening, a connection from the first fluid opening to the tank at about the normal water level therein and a second fluid flow opening for connection to the intake side of the pump, a check valve controlling the connection from said first fluid opening to permit air flow in either direction but preventing water flow from said tank to said charger, an air intake communicating with the interior of said charger, a Venturi-type aspirator having a vented constricted throat in direct communication with the interior of said casing, said aspirator receiving water directly from the discharge line of said pump and. discharging water to the intake side of said pump through said second fluid flow opening, a float-controlled valve controlling fluid flow through said second fluid flow opening and interposed between the discharge of said aspirator and the intake side of the pump, said aspirator withdrawing water through its vented throat from the interior of said casing when said float-controlled valve is open and Water flow through said aspirator is established, thus drawing air into the casing, and said aspirator discharging water through its vented throat into the interior of the casing, when said float-controlled valve is closed and water flow through the aspirator continues, to displace the air from the casing into the tank through said first fluid flow opening.

ARTHUR W. BURKS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,172,057 Burks Sept. 5, 1939 2,172,097 Burks 1 Sept. 5, 1939 2,457,863 Burks Jan. 4, 1949 2,509,130 Burks May 23, 1950

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