Fluid supply surge control system

Claim 2

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: means for pumping the fluid from the reservoir, a manifold, pump outlet means communicating said pumping means with said manifold, outlet means communicating with said manifold for discharging the fluid, vent return means communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, high pressure sensing means communicating with said manifold, said high pressure sensing means having a sensing threshold, low pressure sensing means communicating with said manifold, said low pressure sensing means having a sensing threshold which is less than said sensing threshold of said high pressure sensing means, control means for said pumping means for energizing said pumping means in response to said low pressure sensing means when the pressure of the fluid in said manifold falls below said low pressure sensing means threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure sensing means threshold, and vent control means for closing said vent return means and opening said vent return means in response to said high pressure sensing means when the pressure of the fluid in said manifold exceeds said high pressure sensing means threshold, whereby the pressure of said fluid in said manifold is decreased to below said high pressure sensing means threshold wherein when the pressure sensed in said manifold is between said high and low pressure sensing means thresholds, said pumping means is deenergized and said vent return means is closed.

Claim 3

A fluid supply system according to claim 1 further comprising; said fluid supply system adapted for drawing fluid from more than one reservoir and said system further having a fluid source switching means for switching from one of the reservoirs to another of the reservoirs upon depletion of the fluid from one of the reservoirs.

Claim 4

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: means for pumping the fluid from the reservoir, a manifold, a pump outlet conduit communicating said pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a vent return line communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold which is less than said sensing threshold of said high pressure sensing means, control means for said pumping means for energizing said pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, and vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold is decreased to below said high pressure switch threshold wherein when the pressure sensed in said manifold is between said high and low pressure sensing means thresholds, said pumping means is deenergized and said vent return means is closed.

Claim 5

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: means for pumping the fluid from the reservoir, a manifold, a pump outlet conduit communicating said pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a vent return line communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold which is less than said sensing threshold of said high pressure sensing means, control means for said pumping means for energizing said pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, and vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold is decreased to below said high pressure switch threshold wherein when the pressure sensed in said manifold is between said high and low pressure sensing means thresholds, said pumping means is deenergized and said vent return means is closed.

Claim 6

A fluid supply system according to claim 3 wherein said high pressure switch threshold is adjustable.

Claim 7

A fluid supply system according to claim 3 wherein said low pressure switch threshold is adjustable.

Claim 8

A fluid supply system according to claim 3 further comprising a vent relief pressure valve in said vent return line, said vent relief pressure valve restricting the flow of the fluid in said vent return line.

Claim 9

A fluid supply system according to claim 3 wherein the restriction provided by said vent relief pressure valve is variable.

Claim 10

A fluid supply system according to claim 3 wherein said vent control means comprises; a pump vent control valve having a pneumatically actuated cylinder which actuates a fluid valve in said vent return line, and a vent control switch actuated by a signal from said high pressure switch and having a valve which controls the delivery of compressed air to said pump vent control valve cylinder.

Claim 11

A fluid supply system according to claim 3 further comprising a check valve in said pump outlet conduit to prevent reversed flow of the fluid in said pump outlet conduit.

Claim 12

A fluid supply system according to claim 3 further comprising a manual actuation circuit permitting bypassing of said manifold, said manual actuation circuit comprising, a first valve in said pump outlet conduit, a bypass conduit connecting said pump outlet conduit with said outlet conduit, a second valve in said bypass conduit, and a third valve in said outlet conduit.

Claim 13

A fluid supply system according to claim 3 further comprising; said fluid supply system adapted to drawing fluid from more than one reservoir and said system further having a fluid source switching means for switching from one of the reservoirs to another of the reservoirs upon depletion of the fluid from one of the reservoirs.

Claim 14

A fluid supply system according to claim 3 wherein both said high pressure switch and said low pressure switch are connected to said manifold such that the distance of the flow path therebetween is three inches or less.

Claim 15

A fluid supply system according to claim 3 wherein said pumping means comprises a pneumatically powered pump.

Claim 16

A fluid supply system according to claim 13 wherein said control means for said pumping means comprises; a pump control switch which controls the delivery of compressed air to said pump, said pump control switch including a pump control switch solenoid which is electrically connected with said low pressure switch to control the operation of a pump control switch valve.

Claim 17

A fluid supply system according to claim 3 wherein said high pressure switch and said low pressure switch are integrated into a single housing.

Claim 18

A fluid supply system according to claim 15 wherein said single housing defines a fitting which communicates with said manifold, said fitting having an internal bore having a diameter greater than approximately 0.1875 inch.

Claim 19

A fluid supply system for controlling the pressure of fluid delivery from either a first or a second fluid reservoir comprising, first pumping means for pumping the fluid from the first reservoir, second pumping means for pumping the fluid from the second reservoir, a manifold, a first pump outlet conduit communicating said first pumping means with said manifold, a second pump outlet conduit communicating said second pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a first vent return line communicating said manifold with the first reservoir for returning the fluid from said manifold to the first reservoir, a second vent return line communicating said manifold with the second reservoir for returning the fluid from said manifold to the second reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said first and second pumping means for energizing either of said first or second pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold is decreased to below said high pressure switch threshold, and fluid source switching means for switching from one of the reservoirs to the other of the reservoirs upon depletion of the fluid from a reservoir.

Claim 20

A fluid supply system for controlling the pressure of fluid delivery from either a first or a second fluid reservoir comprising, first pumping means for pumping the fluid from the first reservoir, second pumping means for pumping the fluid from the second reservoir, a manifold, a first pump outlet conduit communicating said first pumping means with said manifold, a second pump outlet conduit communicating said second pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a first vent return line communicating said manifold with the first reservoir for returning the fluid from said manifold to the first reservoir, a second vent return line communicating said manifold with the second reservoir for returning the fluid from said manifold to the second reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said first and second pumping means for energizing either of said first or second pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold is decreased to below said high pressure switch threshold, and fluid source switching means for switching from one of the reservoirs to the other of the reservoirs upon depletion of the fluid from a reservoir.

Claim 21

A fluid supply system according to claim 17 wherein said fluid source switching means comprises; a first pilot valve which includes a pneumatic valve which switches in response to fluid pressure in said first pump outlet conduit, a second pilot valve which includes a pneumatic valve which switches in response to fluid pressure in said second pump outlet conduit, a first pilot signal line connected to said first pilot pneumatic valve, a second pilot signal line connected to said second pilot pneumatic valve, a pump selective valve which switches in response to the presence of air pressure in either of said first or second pilot signal lines to switch between controlling either said first or said second pumping means, and a vent selector valve which switches in response to the presence of air pressure in either of said first or second pilot signal lines to switch the return of fluid from said manifold to either of the first or second reservoir.

Claim 22

A fluid supply system according to claim 17 wherein said high pressure switch threshold is adjustable.

Claim 23

A fluid supply system according to claim 17 wherein said low pressure switch threshold is adjustable.

Claim 24

A fluid supply system according to claim 17 wherein said vent control means comprises; a pump vent control valve having a pneumatically actuated cylinder which actuates a fluid valve in said vent return line, and a vent control switch actuated by a signal from said high pressure switch and having a valve which controls the delivery of compressed air to said pump vent control valve cylinder.

Claim 25

A fluid supply system according to claim 17 further comprising a check valve in said pump outlet conduit to prevent reserved flow of the fluid in said pump outlet conduit.

Claim 26

A fluid supply system according to claim 17 further comprising a manual actuation circuit permitting bypassing of said manifold, said manual actuation circuit comprising, a pair of first valves in said pump outlet conduits, a pair of bypass conduits connecting said pump outlet conduits with said outlet conduit, a pair of second valves in said bypass conduits, and a third valve in said outlet conduit.

Claim 27

A fluid supply system according to claim 17 wherein both said high pressure switch and said low pressure switch are connected to said manifold such that the distance of the flow path therebetween is three inches or less.

Claim 28

A fluid supply system according to claim 17 further comprising a vent relief pressure valve in said vent return line, said vent relief pressure valve restricting the flow of the fluid in said vent return line.

Claim 29

A fluid supply system according to claim 25 wherein the restriction provided by said vent relief pressure valve is variable.

Claim 30

A fluid supply system according to claim 17 wherein said pumping means is a pneumatically powered pump.

Claim 31

A fluid supply system according to claim 27 wherein said pump control means for said pumping means comprises; a pump control switch which controls the delivery of compressed air to said pumps, said pump control switch including a pump control switch solenoid which is electrically connected with said low pressure switch to control the operation of a pump control switch valve.

Claim 32

A fluid supply system according to claim 17 wherein said high pressure switch and said low pressure switch are integrated into a single housing.

Claim 33

A fluid supply system according to claim 29 wherein said single housing defines a fitting which communicates with said manifold, said fitting having an internal bore having a diameter greater than approximately 0.1875 inch.

Claim 34

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: means for pumping the fluid from the reservoir, a manifold, a pump outlet conduit communicating said pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a vent return line communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, a vent relief pressure valve in said vent return line, said vent relief pressure valve restricting the flow of the fluid in said vent return line, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said pumping means for energizing said pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, and vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold decreased to below said high pressure switch threshold.

Claim 35

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: means for pumping the fluid from the reservoir, a manifold, a pump outlet conduit communicating said pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a vent return line communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, a vent relief pressure valve in said vent return line, said vent relief pressure valve restricting the flow of the fluid in said vent return line, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said pumping means for energizing said pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, and vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold decreased to below said high pressure switch threshold.

Claim 36

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: a pneumatically powered pump for pumping the fluid from the reservoir, a manifold, a pump outlet conduit communicating said pump with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a vent return line communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said pump for energizing said pump in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, said control means including a pump control switch which controls the delivery of compressed air to said pump, said pump control switch including a pump control switch solenoid which is electrically connected with said low pressure switch to control the operation of a pump control switch valve, and vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold decreased to below said high pressure switch threshold.

Claim 37

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: a pneumatically powered pump for pumping the fluid from the reservoir, a manifold, a pump outlet conduit communicating said pump with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a vent return line communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said pump for energizing said pump in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, said control means including a pump control switch which controls the delivery of compressed air to said pump, said pump control switch including a pump control switch solenoid which is electrically connected with said low pressure switch to control the operation of a pump control switch valve, and vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold decreased to below said high pressure switch threshold.

Claim 38

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: means for pumping the fluid from the reservoir, a manifold, a pump outlet conduit communicating said pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a vent return line communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said pumping means for energizing said pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, and vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold decreased to below said high pressure switch threshold, said vent control means including a pump vent control valve having a pneumatically actuated cylinder which actuates a fluid valve in said vent return line, and a vent control switch actuated by a signal from said high pressure switch and having a valve which controls the delivery of compressed air to said pump vent control valve cylinder.

Claim 39

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: means for pumping the fluid from the reservoir, a manifold, a pump outlet conduit communicating said pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a vent return line communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said pumping means for energizing said pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, and vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold decreased to below said high pressure switch threshold, said vent control means including a pump vent control valve having a pneumatically actuated cylinder which actuates a fluid valve in said vent return line, and a vent control switch actuated by a signal from said high pressure switch and having a valve which controls the delivery of compressed air to said pump vent control valve cylinder.

Claim 40

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: means for pumping the fluid from the reservoir, a manifold, a pump outlet conduit communicating said pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a vent return line communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said pumping means for energizing said pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, and vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold decreased to below said high pressure switch threshold, and a manual actuation circuit permitting bypassing of said manifold, said manual actuation circuit including a first valve in said pump outlet conduit, a bypass conduit connecting said pump outlet conduit with said outlet conduit, a second valve in said bypass conduit, and a third valve in said outlet conduit.

Claim 41

A fluid supply system for controlling the pressure of fluid delivered from a fluid reservoir, comprising: means for pumping the fluid from the reservoir, a manifold, a pump outlet conduit communicating said pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a vent return line communicating said manifold with the reservoir for returning the fluid from said manifold to the reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said pumping means for energizing said pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, and vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold decreased to below said high pressure switch threshold, and a manual actuation circuit permitting bypassing of said manifold, said manual actuation circuit including a first valve in said pump outlet conduit, a bypass conduit connecting said pump outlet conduit with said outlet conduit, a second valve in said bypass conduit, and a third valve in said outlet conduit.

Claim 42

A fluid supply system for controlling the pressure of fluid delivery from either a first or a second fluid reservoir, comprising: first pumping means for pumping the fluid from the first reservoir, second pumping means for pumping the fluid from the second reservoir, a manifold, a first pump outlet conduit communicating said first pumping means with said manifold, a second pump outlet conduit communicating said second pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a first vent return line communicating said manifold with the first reservoir for returning the fluid from said manifold to the first reservoir, a second vent return line communicating said manifold with the second reservoir for returning the fluid from said manifold to the second reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said first and second pumping means for energizing either of said first or second pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold is decreased to below said high pressure switch threshold, and fluid source switching means for switching from one of the reservoirs to the other of the reservoirs upon depletion of the fluid from a reservoir, said fluid source switch means including, a first pilot valve which includes a pneumatic valve which switches in response to fluid pressure in said first pump outlet conduit, a second pilot valve which includes a pneumatic valve which switches in response to fluid pressure in said second pump outlet conduit, a first pilot signal line connected to said first pilot pneumatic valve, a second pilot signal line connected to said second pilot pneumatic valve, a pump selective valve which switches in response to the presence of air pressure in either of said first or second pilot signal lines to switch between controlling either said first or said second pumping means, and a vent selector valve which switches in response to the presence of air pressure in either of said first or second pilot signal lines to switch the return of fluid from said manifold to either of the first or second reservoir.

Claim 43

A fluid supply system for controlling the pressure of fluid delivery from either a first or a second fluid reservoir, comprising: first pumping means for pumping the fluid from the first reservoir, second pumping means for pumping the fluid from the second reservoir, a manifold, a first pump outlet conduit communicating said first pumping means with said manifold, a second pump outlet conduit communicating said second pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a first vent return line communicating said manifold with the first reservoir for returning the fluid from said manifold to the first reservoir, a second vent return line communicating said manifold with the second reservoir for returning the fluid from said manifold to the second reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said first and second pumping means for energizing either of said first or second pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold is decreased to below said high pressure switch threshold, and fluid source switching means for switching from one of the reservoirs to the other of the reservoirs upon depletion of the fluid from a reservoir, said fluid source switch means including, a first pilot valve which includes a pneumatic valve which switches in response to fluid pressure in said first pump outlet conduit, a second pilot valve which includes a pneumatic valve which switches in response to fluid pressure in said second pump outlet conduit, a first pilot signal line connected to said first pilot pneumatic valve, a second pilot signal line connected to said second pilot pneumatic valve, a pump selective valve which switches in response to the presence of air pressure in either of said first or second pilot signal lines to switch between controlling either said first or said second pumping means, and a vent selector valve which switches in response to the presence of air pressure in either of said first or second pilot signal lines to switch the return of fluid from said manifold to either of the first or second reservoir.

Claim 44

A fluid supply system for controlling the pressure of fluid delivery from either a first or a second fluid reservoir, comprising: first pumping means for pumping the fluid from the first reservoir, second pumping means for pumping the fluid from the second reservoir, a manifold, a first pump outlet conduit communicating said first pumping means with said manifold, a second pump outlet conduit communicating said second pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a first vent return line communicating said manifold with the first reservoir for returning the fluid from said manifold to the first reservoir, a first vent relief pressure valve in said first vent return line, said first vent relief pressure valve restricting the flow of the fluid in said first vent return line wherein the restriction provided by said first vent relief pressure valve is variable, a second vent return line communicating said manifold with the second reservoir for returning the fluid from said manifold to the second reservoir, a second vent relief pressure valve in said second vent return line, said second vent relief pressure valve restricting the flow of the fluid in said second vent return line wherein the restriction provided by said second vent relief pressure is variable, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said first and second puming means for energizing either of said first or second pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold.

Claim 45

A fluid supply system for controlling the pressure of fluid delivery from either a first or a second fluid reservoir, comprising: first pumping means for pumping the fluid from the first reservoir, second pumping means for pumping the fluid from the second reservoir, a manifold, a first pump outlet conduit communicating said first pumping means with said manifold, a second pump outlet conduit communicating said second pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a first vent return line communicating said manifold with the first reservoir for returning the fluid from said manifold to the first reservoir, a first vent relief pressure valve in said first vent return line, said first vent relief pressure valve restricting the flow of the fluid in said first vent return line wherein the restriction provided by said first vent relief pressure valve is variable, a second vent return line communicating said manifold with the second reservoir for returning the fluid from said manifold to the second reservoir, a second vent relief pressure valve in said second vent return line, said second vent relief pressure valve restricting the flow of the fluid in said second vent return line wherein the restriction provided by said second vent relief pressure is variable, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said first and second puming means for energizing either of said first or second pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold.

Claim 46

A fluid supply system for controlling the pressure of fluid delivery from either a first or a second fluid reservoir, comprising: a first pneumatically powered pump for pumping the fluid from the first reservoir, a second pneumatically powered pump for pumping the fluid from the second reservoir, a manifold, a first pump outlet conduit communicating said first pump with said manifold, a second pump outlet conduit communicating said second pump with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a first vent return line communicating said manifold with the first reservoir for returning the fluid from said manifold to the first reservoir, a second vent return line communicating said manifold with the second reservoir for returning the fluid from said manifold to the second reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, and control means for said first and second pumps for energizing either of said first or second pumps in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, said control means including a pump control switch which controls the delivery of compressed air to said pumps, said pump control switch including a pump control switch solenoid which is electrically connected with said low pressure switch to control the operation of a pump control switch valve.

Claim 47

A fluid supply system for controlling the pressure of fluid delivery from either a first or a second fluid reservoir, comprising: a first pneumatically powered pump for pumping the fluid from the first reservoir, a second pneumatically powered pump for pumping the fluid from the second reservoir, a manifold, a first pump outlet conduit communicating said first pump with said manifold, a second pump outlet conduit communicating said second pump with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a first vent return line communicating said manifold with the first reservoir for returning the fluid from said manifold to the first reservoir, a second vent return line communicating said manifold with the second reservoir for returning the fluid from said manifold to the second reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, and control means for said first and second pumps for energizing either of said first or second pumps in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, said control means including a pump control switch which controls the delivery of compressed air to said pumps, said pump control switch including a pump control switch solenoid which is electrically connected with said low pressure switch to control the operation of a pump control switch valve.

Claim 48

A fluid supply system for controlling the pressure of fluid delivery from either a first or a second fluid reservoir, comprising: first pumping means for pumping the fluid from the first reservoir, second pumping means for pumping the fluid from the second reservoir, a manifold, a first pump outlet conduit communicating said first pumping means with said manifold, a second pump outlet conduit communicating said second pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a first vent return line communicating said manifold with the first reservoir for returning the fluid from said manifold to the first reservoir, a second vent return line communicating said manifold with the second reservoir for returning the fluid from said manifold to the second reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said first and second pumping means for energizing either of said first or second pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold is decreased to below said high pressure switch threshold, said vent control means including a pump vent control valve having a pneumatically actuated cylinder which actuates a fluid valve in said vent return line, and a vent control switch actuated by a signal from said high pressure switch and having a valve which controls the delivery of compressed air to said pump vent control valve cylinder, and fluid source switching means for switching from one of the reservoirs to the other of the reservoirs upon depletion of the fluid from a reservoir.

Claim 49

A fluid supply system for controlling the pressure of fluid delivery from either a first or a second fluid reservoir, comprising: first pumping means for pumping the fluid from the first reservoir, second pumping means for pumping the fluid from the second reservoir, a manifold, a first pump outlet conduit communicating said first pumping means with said manifold, a second pump outlet conduit communicating said second pumping means with said manifold, an outlet conduit communicating with said manifold for discharging the fluid, a first vent return line communicating said manifold with the first reservoir for returning the fluid from said manifold to the first reservoir, a second vent return line communicating said manifold with the second reservoir for returning the fluid from said manifold to the second reservoir, a high pressure switch communicating with said manifold, said high pressure switch having a switching threshold, a low pressure switch communicating with said manifold, said low pressure switch having a switching threshold, control means for said first and second pumping means for energizing either of said first or second pumping means in response to said low pressure switch when the pressure of the fluid in said manifold falls below said low pressure switch threshold, whereby the pressure of said fluid in said manifold is increased to above said low pressure switch threshold, vent control means for closing said vent return line and opening said vent return line in response to said high pressure switch when the pressure of the fluid in said manifold exceeds said high pressure switch threshold, whereby the pressure of said fluid in said manifold is decreased to below said high pressure switch threshold, said vent control means including a pump vent control valve having a pneumatically actuated cylinder which actuates a fluid valve in said vent return line, and a vent control switch actuated by a signal from said high pressure switch and having a valve which controls the delivery of compressed air to said pump vent control valve cylinder, and fluid source switching means for switching from one of the reservoirs to the other of the reservoirs upon depletion of the fluid from a reservoir.