Suction shutoff valve

Abstract

A suction shutoff valve of a compressor which includes a modulating valve. The modulating valve includes a valve disk for covering a valve aperture, a bellows in sealed engagement with the egress end of a valve body, and a valve stem connecting the valve disk and the bellows. A bellows spring is disposed in the bellows for biasing the valve disk to open the valve aperture. When the pressure in the suction chamber decreases below a predetermined pressure, the bellows spring moves the bellows and the valve disk to open the valve aperture and increase fluid flow from the compression chamber to the bellows chamber to subsequently allow the valve piston to uncover the holes of the valve body and increase fluid flow through the suction shutoff valve to the suction chamber.

1 . A variable displacement axial piston compressor comprising:
 a suction passage for moving a gaseous fluid through said compressor;   a suction shutoff valve disposed in said suction passage for regulating gaseous fluid flow;   said suction shutoff valve including a valve body;   a valve piston slidably disposed in said valve body;   said valve body defining a chamber flange extending radially inward from said valve body and defining a compression chamber between said valve piston and said chamber flange;   said valve piston defining a valve orifice for restricting fluid flow through said valve piston;   said chamber flange defining a flange orifice for restricting fluid flow through said chamber flange; and   a modulating valve for variably and incrementally increasing fluid flow through said chamber flange from said compression chamber to said suction passage in response to a decrease in the pressure in said suction passage below a predetermined pressure.   
   
   
       2 . The modulating valve as set forth in  claim 1  wherein said chamber flange defines a valve aperture and said modulating valve includes a valve disk for covering said valve aperture in response to an increase in the pressure in said suction passage above said predetermined pressure and an actuator mechanism for moving said valve disk to open said valve disk in response to a decrease in the pressure in said suction passage below said predetermined pressure. 
   
   
       3 . The modulating valve as set forth in  claim 2  wherein said valve body extends between an inlet end and an egress end and defines a bellows chamber being closed and extending from said chamber flange to said egress end and said bellows chamber defining a discharge orifice larger than said flange orifice and smaller than said flange orifice combined with said valve aperture. 
   
   
       4 . The modulating valve as set forth in  claim 3  wherein said modulating valve includes a bellows closed and in sealed engagement with said egress end of said valve body at a bellows pressure below said predetermined pressure and extending axially from said egress end of said valve body to a bellows top and a valve stem extending axially from said bellows top through said valve aperture and connecting to said valve disk for opening and closing said valve aperture in response to axial incremental movement of said bellows top for variably and incrementally increasing fluid flow from said compression chamber to said bellows chamber. 
   
   
       5 . The modulating valve as set forth in  claim 4  wherein said modulating valve includes a bellows spring disposed in said bellows and interacting between said bellows top and said egress end of said valve body for biasing said valve disk axially upward from said valve aperture to open said valve aperture in response to a decrease in pressure in said bellows chamber below said predetermined pressure. 
   
   
       6 . The suction shutoff valve as set forth in  claim 5  wherein said suction shutoff valve includes a plurality of holes defined by said valve body and circumferentially spaced from each other in said compression chamber about said inlet end of said valve body, and a piston spring disposed in said compression chamber and interacting between said valve piston and said chamber flange for biasing said valve piston axially upward from said chamber flange to define a closed position covering said holes and compressible for allowing said valve piston to move axially from said closed position to a fully open position uncovering said holes to allow fluid communication from said inlet end of said suction shutoff valve to said suction passage. 
   
   
       7 . The suction shutoff valve as set forth in  claim 6  wherein said valve orifice is larger than said flange orifice for establishing a pressure in said compression chamber which is greater than the pressure in said suction passage in said closed position for biasing said valve piston axially upward from said chamber flange to define a closed position covering said holes. 
   
   
       8 . A variable displacement axial piston compressor comprising:
 a cylinder housing, a valve plate, and a cylinder head;   said cylinder housing defining piston cylinders;   said cylinder head defining an electronic control valve cavity for receiving an electronic control valve;   said cylinder head defining a suction port and a valve chamber and a suction chamber and discharge ports all disposed serially for moving a gaseous fluid through said compressor and said valve chamber and said suction chamber together making up a suction passage;   said valve plate disposed between said cylinder housing and said cylinder head for controlling fluid communication between said suction chamber and said piston cylinders and said discharge ports;   said suction port having an entry diameter followed axially by said suction port having a middle diameter less than said entry diameter and an outlet diameter less than said middle diameter;   said valve chamber having a constant valve chamber diameter greater than said outlet diameter to define a shoulder there between for receiving the gaseous fluid from said outlet diameter of said suction port;   a suction shutoff valve disposed in said valve chamber and aligned on an axis for regulating gaseous fluid flow to said suction chamber;   said suction shutoff valve including a valve body extending between an inlet end and an egress end and having a valve flange extending radially outward from said inlet end and in engagement with said valve chamber diameter and said shoulder;   said valve body being tubular to define a tube diameter less than said valve chamber diameter and defining an annular space in fluid communication with said suction chamber;   a valve retainer ring disposed in said inlet end of said valve body;   said valve body defining an inner diameter and a plurality of holes circumferentially spaced from each other and disposed axially adjacent said valve flange and said valve retainer ring for establishing fluid communication between said inner diameter of said valve body and said annular space about said valve body;   a valve piston slidably disposed in said inlet end of said valve body and having a base and a skirt extending axially from said base and engaging said inner diameter of said valve body;   said valve body defining a chamber flange extending radially inward from said inner diameter of said valve body and defining a compression chamber being closed between said valve piston and said chamber flange;   a piston spring disposed in said compression chamber and interacting between said valve piston and said chamber flange for biasing said valve piston axially into engagement with said valve retainer ring to define a closed position covering said holes and compressible for allowing said valve piston to move axially from said closed position to a fully open position uncovering said holes to allow fluid communication from said inlet end to said annular space;   said valve body defining an annular stop extending radially inward from said inner diameter of said valve body for limiting movement of said valve piston to said fully open position;   said chamber flange presenting a spring seat extending axially from said chamber flange into said compression chamber for radially positioning said piston spring in said compression chamber;   said valve piston defining a mound extending axially into said piston spring in said compression chamber for radially positioning said piston spring in said compression chamber;   said chamber flange defining a flange orifice disposed radially from said axis and having a flange orifice diameter of 1.8 mm to present a flange orifice area for restricting fluid flow through said chamber flange;   said base of said valve piston defining a valve orifice disposed on said axis and having a valve orifice diameter of 2.4 mm to present a valve piston area for restricting fluid flow through said valve piston; and   characterized by a modulating valve for variably and incrementally increasing fluid flow through said chamber flange from said compression chamber to said suction chamber in response to a decrease in the pressure in said suction chamber below a predetermined pressure;   said modulating valve including a bellows chamber defined by said valve body and being closed and extending from said chamber flange to said egress end;   said bellows chamber including a discharge orifice disposed in said egress end of said valve body and radially offset from said axis and having a discharge orifice diameter of 2.8 mm to present a discharge orifice area for restricting fluid flow from said bellows chamber to said suction chamber;   said modulating valve including a bellows being closed and in sealed engagement with said valve body to establish an internal bellows pressure of 0 psia and extending axially from said egress end of said valve body to a bellows top and having a bellows diameter less than said inner diameter of said valve body;   said modulating valve including a valve aperture defined by said chamber flange defining a valve aperture adjacent said bellows top;   said modulating valve including a valve disk for covering said valve aperture in said closed position and a valve stem extending axially from said valve disk through said aperture and connecting to said bellows top for opening and closing said valve aperture in response to axial incremental movement of said bellows top for variably and incrementally increasing fluid flow from said compression chamber to said bellows chamber;   said modulating valve including a bellows spring disposed in said bellows and interacting between said bellows top and said egress end of said valve body for biasing said valve disk axially upward from said valve aperture to open said valve aperture in response to a decrease in pressure in said bellows chamber below said predetermined pressure; and   whereby fluid flows through said valve orifice and said flange orifice and said discharge orifice in said closed position and whereby said bellows spring axially moves said bellows and said valve disk to open said valve aperture in response to a decrease in the pressure of said suction chamber below said predetermined pressure to increase the fluid flow from said compression chamber to said bellows chamber and through said discharge port to said suction chamber and thereby expose said valve piston to the decreased suction chamber pressure to overcome the force of said piston spring and move said valve piston axially to uncover said holes of said valve body and increase fluid flow through said suction shutoff valve to said suction chamber.   
   
   
       9 . A suction shutoff valve for deposition in a variable displacement axial piston compressor, said suction shutoff valve comprising:
 a valve body;   a valve piston slidably disposed in said valve body;   said valve body defining a chamber flange extending radially inward from said valve body and defining a compression chamber between said valve piston and said chamber flange;   said valve piston defining a valve orifice for restricting fluid flow through said valve piston;   said chamber flange defining a flange orifice for restricting fluid flow through said chamber flange; and   a modulating valve for variably and incrementally increasing fluid flow through said chamber flange from said compression chamber to the suction passage in response to a decrease in the pressure in the suction passage below a predetermined pressure.   
   
   
       10 . The modulating valve as set forth in  claim 9  wherein said chamber flange defines a valve aperture and said modulating valve includes a valve disk for covering said valve aperture in response to an increase in the pressure in the suction passage above said predetermined pressure and an actuator mechanism for moving said valve disk to open said valve disk in response to a decrease in the pressure in the suction passage below said predetermined pressure. 
   
   
       11 . The modulating valve as set forth in  claim 10  wherein said valve body extends between an inlet end and an egress end and defines a bellows chamber being closed and extending from said chamber flange to said egress end and said bellows chamber defining a discharge orifice larger than said flange orifice and smaller than said flange orifice combined with said valve aperture. 
   
   
       12 . The modulating valve as set forth in  claim 11  wherein said modulating valve includes a bellows closed and in sealed engagement with said egress end of said valve body at a bellows pressure below said predetermined pressure and extending axially from said egress end of said valve body to a bellows top and a valve stem extending axially from said bellows top through said valve aperture and connecting to said valve disk for opening and closing said valve aperture in response to axial incremental movement of said bellows top for variably and incrementally increasing fluid flow from said compression chamber to said bellows chamber. 
   
   
       13 . The modulating valve as set forth in  claim 12  wherein said modulating valve includes a bellows spring disposed in said bellows and interacting between said bellows top and said egress end of said valve body for biasing said valve disk axially upward from said valve aperture to open said valve aperture in response to a decrease in pressure in said bellows chamber below said predetermined pressure.