Patent ID: 7159611

Claim:
Inline flow control apparatus, comprising a housing having an upper end, a tubular portion and an axial bore having an inlet for pressurized fluid and opening through housing tubular portion and the housing upper end, the housing bore having an axially intermediate bore portion, a fitting removably mounted to the housing and having a top portion, an outlet opening through the top portion and an axially elongated tubular portion extending downwardly from the fitting top portion and having a lower end portion, a piston axially movably extended within the intermediate bore portion and in fluid sealing relationship to the housing wall defining the housing bore, the piston having a top surface and an axially opposite bottom surface within the housing intermediate bore portion portion to which the intermediate bore portion opens, the piston being axially movable along the fitting tubular portion between a fluid flow open position and a fluid flow blocking position and having a first axial bore portion, and a second bore portion having the fitting tubular portion extending therein in both of the piston positions and being in fluid communication with the piston first bore portion, first spring means for resiliently urging the piston to move to its blocking position, the spring means being in abutting relationship to the piston bottom surface, means for applying pressure to the piston top surface for forcing the piston to move from it blocking position to its open position, the fitting tubular portion having a fluid passageway opening to the outlet and to the piston bore second portion, a valve seat mounted to the fitting tubular portion lower end portion and being abuttable against the piston to block fluid flow from the inlet to the passageway when the piston is in its blocking position and to permit fluid flow from inlet to the fitting passageway when the piston is in its open position, and cooperating means for applying pressurized fluid from the inlet to at least part of the piston bottom surface and to the fitting tubular portion passageway when the piston is in its open position and pressurized fluid is being applied at the inlet and blocking the application of fluid under pressure from the inlet to the at least part of the piston bottom surface and to the fitting tubular portion passageway when the piston is in its blocking position, the cooperating means at least in part being defined by the piston and at least one of fitting and the housing.