Unloader valve assembly

Claim 2

AN UNLOADER VALVE ASSEMBLY FOR AIR COMPRESSORS OR THE LIKE COMPRISING A VALVE BODY HAVING A LONGITUDINAL PASSAGE THERETHROUGH FROM ONE END THEREOF, CONSTITUTING ITS INLET END, TO THE OTHER END THEREOF, CONSTITUTING ITS OUTLET END, AN INTERMEDIATE PORTION OF SAID PASSAGE CONSTITUTING A CHAMBER, SAID BODY HAVING AN EXHAUST PORT EXTENDING FROM SAID CHAMBER TO THE EXTERIOR OF SAID BODY, A MAIN VALVE MEMBER AXIALLY SLIDABLE IN SAID PASSAGE BETWEEN A RETRACTED POSITION AND AN ADVANCED POSITION RELATIVE TO THE OUTLET END OF SAID BODY, SAID MAIN VALVE MEMBER HAVING AN AXIAL PASSAGE THERETHROUGH FROM ONE END THEREOF TO THE OTHER, A FIRST PORTION THEREON AXIALLY MOVABLE IN SAID CHAMBER FOR BLOCKING SAID EXHAUST PORT WHEN SAID MAIN VALVE MEMBER IS IN ITS SAID ADVANCED POSITION AND UNBLOCKING SAID EXHAUST PORT WHEN SAID MAIN VALVE MEMBER IS IN ITS SAID RETRACTED POSITION, AND A SECOND PORTION IN THE VALVE BODY PASSAGE ADJACENT ITS OUTLET END FOR CLOSING THE LATTER, SAID MAIN VALVE MEMBER FURTHER HAVING A TRANSFER PORT PROVIDING FOR COMMUNICATION BETWEEN THE AXIAL PASSAGE THEREIN AND SAID CHAMBER, AND AUXILIARY VALVE MEANS FOR SAID MEAN VALVE PASSAGE, SAID AUXILIARY VALVE MEANS BLOCKING FLOW OF AIR THROUGH SAID MAIN VALVE PASSAGE AT A POINT BETWEEN THE OUTLET END OF SAID MAIN VALVE PASSAGE AND SAID TRANSFER PORT WHEN THE MAIN VALVE MEMBER IS IN ITS SAID RETRACTED POSITION, AND CONTINUING TO BLOCK FLOW OF AIR THROUGH SAID MAIN VALVE PASSAGE UNTIL THE MAIN VALVE MEMBER, IN MOVING TO ITS ADVANCED POSITION, BLOCKS SAID EXHAUST PORT, AND THEN OPENING SAID MAIN VALVE PASSAGE.

Claim 3

An unloader valve assembly as set forth in claim 1 wherein said auxiliary valve means comprises a valve seat in said main valve member passage adjacent the outlet end thereof and an auxiliary valve member extending axially through said main valve member passage engageable at its end toward the outlet end of this passage with said seat when the main valve member is retracted.

Claim 4

An unloader valve assembly as set forth in claim 2 wherein said auxiliary valve member is axially slidable in the valve body passage and in the main valve member passage between a retracted position and an advanced position relative to the outlet end of the valve body, and being engageable with said main valve passage seat when both it and the main valve member are retracted, and open off the seat when both it and the main valve are advanced.

Claim 5

An unloader valve assembly as set forth in claim 3 wherein both the main and auxiliary valve members are movable between their retracted and advanced positions by differential air pressure at the inlet and outlet ends of the valve body.

Claim 6

An unloader valve assembly as set forth in claim 4 having interengageable means on the auxiliary valve member and said valve body for limiting the axial movement of the auxiliary valve member.

Claim 7

An unloader valve assembly as set forth in claim 1 having resilient means for biasing said main valve member to its retracted position.

Claim 8

An unloader valve assembly as set forth in claim 6 wherein said main valve is subject to axial vibrational movement in response to fluctuations in fluid flow through the valve and wherein said first portion of the said main valve member is sLidable as a piston in said chamber for dampening said axial vibrational movement.

Claim 9

An unloader valve assembly as set forth in claim 3 wherein said auxiliary valve member is a needle valve having a head which is slidable within the main valve member at its inlet end, and a stem extending axially from said head within said main valve member passage engageable with said valve seat therewithin when the main valve member is retracted.

Claim 10

An unloader valve assembly as set forth in claim 8 wherein said needle valve head has a recess therewithin in communication with the inlet end of said valve body and a port providing for communication between said inlet end and said main valve passage.

Claim 11

An unloader valve assembly for air compressors or the like comprising a valve body having a longitudinal passage therethrough from one end thereof, constituting its inlet end, to the other end thereof, constituting its outlet end, said valve body comprising an inlet section having an internal flange intermediate its ends and an outlet section threaded in said inlet section from the outlet end of the inlet section, said outlet section being formed to define a chamber at its inlet end, said internal flange defining one end of said chamber, said outlet section having a shoulder intermediate its ends defining the other end of said chamber, said valve body having an exhaust port extending from said chamber to the exterior of said body, a main valve member axially slidable in said passage between a retracted position and an advanced position relative to the outlet end of said valve body, said main valve member having an axial passage therethrough from one end thereof to the other, a first portion thereon axially movable in said chamber for blocking said exhaust port when said main valve member is in its said advanced position and unblocking said exhaust port when said main valve member is in its retracted position, a second portion in the valve body passage adjacent its outlet end for closing the latter, and a transfer port providing for communication between the axial passage therein and said chamber, and said valve assembly further having auxiliary valve means for said axial passage in said main valve member, said auxiliary valve means blocking flow of air through said main valve passage at a point between the outlet end of said axial passage and said transfer port when the main valve member is in its retracted position, and continuing to block flow of air through said main valve passage until the main valve member, in moving to its advanced position, blocks said exhaust port, and then opening said main passage.

Claim 12

An unloader valve assembly for air compressors or the like comprising a valve body having a longitudinal passage therethrough from one end thereof, constituting its inlet end, to the other end thereof, constituting its outlet end, said valve body comprising an inlet section having an internal flange intermediate its ends and an outlet section threaded in said inlet section from the outlet end of the inlet section, said outlet section being formed to define a chamber at its inlet end, said internal flange defining one end of said chamber, said outlet section having a shoulder intermediate its ends defining the other end of said chamber, said valve body having an exhaust port extending from said chamber to the exterior of said body, a main valve member axially slidable in said passage between a retracted position and an advanced position relative to the outlet end of said valve body, said main valve member having an axial passage therethrough from one end thereof to the other, a first portion thereon axially movable in said chamber for blocking said exhaust port when said main valve member is in its said advanced position and unblocking said exhaust port when said main valve member is in its retracted position, a second portion in the valve body passage adjacent its outlet end for closing the latter, and a transfer port providing for communication between the axial passage therein and said chamber, and said valve assembly further having auxiliary valve means for said axial passage in said main valve member, said auxiliary valve means blocking flow of air through said main valve passage at a point between the outlet end of said axial passage and said transfer port when the main valve member is in its retracted position, and continuing to block flow of air through said main valve passage until the main valve member, in moving to its advanced position, blocks said exhaust port, and then opening said main passage.

Claim 13

An unloader valve assembly as set forth in claim 10 wherein said main valve member second portion has a sliding sealing fit with a portion of said valve body adjacent its outlet end, the last-said portion of said valve body constituting a check valve seat, and said main valve member second portion has a seal secured thereto engageable with said check valve seat when said main valve member is in its retracted position for blocking the backflow of air through the unloader valve assembly.

Claim 14

An unloader valve assembly as set forth in claim 11 wherein said valve body passage downstream from said check valve seat is flared.

Claim 15

An unloader valve assembly as set forth in claim 10 wherein said auxiliary valve means comprises a valve seat within said main valve passage and a needle valve member, the latter having a head and a needle valve stem extending axially from said head within said main valve passage, said needle valve member being carried by said internal flange for axial sliding movement relative thereto and for axial sliding movement in the main valve passage between a retracted position and an advanced position relative to the outlet end of the valve body, said needle stem engaging said valve seat in said main valve passage when said needle valve member and said main valve member are in their respective retracted positions, said needle valve member being movable With said main valve member with said needle valve stem remaining seated on said main valve passage valve seat until said exhaust port is blocked, and then said main valve member being movable relative to said needle valve member to displace said main valve passage valve seat away from the needle valve stem to permit air to flow therethrough.

Claim 16

An unloader valve assembly as set forth in claim 13 having interengageable means on said needle valve and said valve body for limiting the axial movement of said needle valve member relative to said main valve member.

Claim 17

An unloader valve assembly as set forth in claim 14 wherein said interengageable means comprises a flange adjacent the inlet end of said needle valve member head engageable with said internal flange to limit the downstream movement of said needle valve member and a removable ring secured to said head downstream from the flange, said ring being engageable with said internal flange to limit the upstream movement of said needle valve member.