Pumping system

Claim 2

A pumping unit comprising: a pump for moving a fluid; drive means for driving the pump; a pressure responsive member; means defining a valve seat; conduit means for providing communication between the discharge side of said pump and the valve seat; means for mounting said pressure responsive member for movement between a low pressure position in which said pressure responsive member engages said valve seat and a first area of said pressure responsive member is exposed to the fluid pressure and a high pressure position in whicH said pressure responsive member is moved away from said valve seat to expose a second area of the pressure responsive member to the fluid; yieldable means for urging said pressure responsive member toward the low pressure position, said second area having a greater effective area than the first area whereby the pressure responsive member is moved from the low pressure to the high pressure position in response to a first pressure level and cannot return from the high pressure position to the low pressure position until the pressure level drops below the first pressure level; first means responsive to movement of the pressure responsive member to the low pressure position for causing said drive means to drive said pump and responsive to movement of the pressure responsive member to the high pressure position for causing said drive means to cease driving said pump; and said conduit means including a restricted passage section of relatively small cross sectional area intermediate said pressure responsive member and the pump discharge to thereby interpose a time delay between the instant at which a change in the pressure of the fluid on one side of said restricted passage section occurs and the instant at which such change occurs on the other side of said restricted passage section.

Claim 3

A pumping unit as defined in claim 1 wherein said restricted passage section includes means defining a circumscribing passage section.

Claim 4

A pumping unit as defined in claim 1 including a restrictor member in said conduit means defining said restricted passage section, said restricted passage section circumscribing said restrictor member, said first means including a switch having an actuating member engageable with said pressure responsive member at least in said high pressure position, a flexible valve element mounted on said restrictor member adjacent the upstream end of said restricted passage section, means defining a valve seat against which the flexible valve element can bear, and a support member on the upstream side of said flexible valve element for supporting the latter, said support member having means defining an opening therethrough.

Claim 5

A pumping unit as defined in claim 1 including a housing, a first wall dividing said housing into an inlet chamber and an outlet chamber, said pump being in said housing and having an inlet and an outlet communicating with said inlet chamber and said outlet chamber, respectively, said pressure responsive member being at a sensing zone, a second wall separating said sensing zone from said outlet chamber, said second wall having an aperture therein and said first wall having a restrictor member thereon projecting into said aperture to define said restricted passage section between said outlet chamber and said sensing zone.

Claim 6

A pumping unit comprising: a pump for moving a fluid; drive means for driving the pump; means defining a fluid passage for conducting the fluid from the discharge side of said pump; wall means defining a conduit leading from said fluid passage; a restrictor member in said conduit and spaced from said wall means by a radially narrow clearance space which substantially circumscribes the restrictor member to define a restricted passage section, said conduit on the side of said restricted passage section downstream from said fluid passage defining a sensing zone with said restricted passage section causing a time delay for the transmission of pressure changes between said sensing zone and the other side of said restricted passage section; and means responsive to a first fluid pressure level at said sensing zone for causing said drive means to drive said pump and responsive to a second fluid pressure level at said sensing zone for causing said drive means to cease driving said pump, said second level being higher than said first level.

Claim 7

A pumping unit comprising: a pump for moving a fluid; drive means for driving the pump; means defining a fluid passage for conducting the fluid from the discharge side of said pump; wall means defining a conduit leading from said fluid passage; a restrictor member in said conduit and spaced from said wall means by a radially narrow clearance space which substantially circumscribes the restrictor member to define a restricted passage section, said conduit on the side of said restricted passage section downstream from said fluid passage defining a sensing zone with said restricted passage section causing a time delay for the transmission of pressure changes between said sensing zone and the other side of said restricted passage section; and means responsive to a first fluid pressure level at said sensing zone for causing said drive means to drive said pump and responsive to a second fluid pressure level at said sensing zone for causing said drive means to cease driving said pump, said second level being higher than said first level.

Claim 8

A pumping unit as defined in claim 5 including a flexible valve element mounted on said restrictor member adjacent the upstream end of said rEstricted passage section, means defining a valve seat against which the flexible valve element can bear, and disc-like support means mounted on the upstream side of said flexible valve element for supporting said flexible valve element against substantial movement in the upstream direction whereby said flexible valve element serves as a check valve to prevent reverse flow to the pump, said support means having means defining at least one opening therethrough.

Claim 11

A device as defined in claim 7 wherein said control device includes a switch having an actuating member for causing the switch to perform said control functions, said pressure responsive member being engageable with said actuating member in said high pressure position.

Claim 12

A device as defined in claim 7 including a restrictor member in said conduit and spaced from the wall of said conduit to define said restriction, said restriction circumscribing said restrictor member.

Claim 13

A pumping unit comprising: a pump for moving a fluid; drive means for driving the pump; a pressure responsive member; means defining a valve seat; conduit means for providing communication between the discharge side of said pump and the valve seat; means for mounting said pressure responsive member for movement between a low pressure position in which said pressure responsive member engages said valve seat and a first area of said pressure responsive member is exposed to the fluid pressure and a high pressure position in which said pressure responsive member is moved away from said valve seat to expose a second area of the pressure responsive member to the fluid; yieldable means for urging said pressure responsive member toward the low pressure position, said second area having a greater effective area than the first area whereby the pressure responsive member is moved from the low pressure position to the high pressure position in response to a first pressure level and cannot return from the high pressure position to the low pressure position until the pressure level drops below the first pressure level; first means responsive to the pressure responsive member being in the low prEssure position for causing said drive means to drive said pump and responsive to the pressure responsive member being in the high pressure position for causing said drive means to cease driving said pump; means defining a fluid passage leading from the pump discharge for carrying the fluid from the pump discharge; a check valve seat in said fluid passage; a flexible washer-like valve element; means for mounting said flexible valve element in said fluid passage so that said flexible valve element can bear against said check valve seat; and a disc-like support member mounted on the upstream side of said flexible valve element for supporting said flexible valve element against substantial movement in the upstream direction wherein said flexible valve element serves as a check valve to prevent backflow to the pump, said support member having means defining at least one opening therethrough.

Claim 14

A pumping unit comprising: a pump for moving a fluid; drive means for driving the pump; a pressure responsive member; means defining a valve seat; conduit means for providing communication between the discharge side of said pump and the valve seat; means for mounting said pressure responsive member for movement between a low pressure position in which said pressure responsive member engages said valve seat and a first area of said pressure responsive member is exposed to the fluid pressure and a high pressure position in which said pressure responsive member is moved away from said valve seat to expose a second area of the pressure responsive member to the fluid; yieldable means for urging said pressure responsive member toward the low pressure position, said second area having a greater effective area than the first area whereby the pressure responsive member is moved from the low pressure position to the high pressure position in response to a first pressure level and cannot return from the high pressure position to the low pressure position until the pressure level drops below the first pressure level; first means responsive to the pressure responsive member being in the low prEssure position for causing said drive means to drive said pump and responsive to the pressure responsive member being in the high pressure position for causing said drive means to cease driving said pump; means defining a fluid passage leading from the pump discharge for carrying the fluid from the pump discharge; a check valve seat in said fluid passage; a flexible washer-like valve element; means for mounting said flexible valve element in said fluid passage so that said flexible valve element can bear against said check valve seat; and a disc-like support member mounted on the upstream side of said flexible valve element for supporting said flexible valve element against substantial movement in the upstream direction wherein said flexible valve element serves as a check valve to prevent backflow to the pump, said support member having means defining at least one opening therethrough.