Importance

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Abstract

An injection device is operable to force a treatment fluid into a refrigerant circuit having an R-134a service fitting thereon and includes a tubular container in which the treatment fluid is disposed. The container has an outlet structure with a body section adapted to sealingly receive and open the service fitting, and a rotatable nut portion operative to deform the body section and releasably lock it onto the service fitting. A hollow plunger member is threaded into the container and may be (1) threadingly advanced into the container to force the treatment fluid outwardly therefrom into the refrigerant circuit, or (2) serve as a conduit through which a pressurized driving fluid may be forced into the container to drive the treatment fluid into the refrigerant circuit. Inlet and outlet check valve structures are incorporated into the device to prevent undesirable fluid backflow therethrough. The inlet check valve structure includes an annular elastomeric sleeve member that has a flat cross-sectional shape around its periphery, circumscribes a tubular outlet portion of the plunger member, and functions to block side wall outlet openings therein in a manner preventing fluid backflow therethrough, while at the same time being fluid pressure-expandable in a radial direction to permit fluid flow through the outlet openings in the desired operative direction.

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First Claim