Manual seal coupler

A coupler for connecting the service port of a refrigeration fluid-containing system to an exit conduit, said apparatus comprising:

• (i) an elongated coupling body having
• (a) a hollow axially aligned service port collar disposed at one end of said coupling body and operable to sealably receive the service port of the refrigeration fluid-containing system in fluid-tight relationship, and
• (b) a hollow exit collar proximate the other end of said coupling body and operable to sealably receive said exit conduit in fluid-tight relationship;
• (ii) a stem threadably attached to the coupling body for axial movement within the coupling body between a first open position when fully advanced and a second closed position when fully retracted, said stem having
• (a) an axially aligned elongated cylindrical chamber defined within said stem,
• (b) means communicating between said cylindrical chamber and said service port collar,
• (c) means communicating between said cylindrical chamber and said exit collar, and
• (d) a seat surface circumferentially and inwardly defined on the inside wall of the cylindrical chamber between said exit collar communication means and said service port collar communication means;
• (iii) sealing means disposed within the cylindrical chamber between said exit collar communication means and said seat surface and complementing the seat surface so as to provide a substantially fluid-tight seal between the exit collar communication means and the service port collar communication means;
• (iv) spring means biasing the sealing means against the seat surface into a normally closed position;
• and
• (v) a rigid plunger axially extending from said sealing means into said service port collar and operable when said stem is in substantially fully advanced position within the coupling body to engage the service port of a refrigeration fluid-containing system in said service port collar and unseat said biased sealing means while assuming a retracted position insufficient to unseat said biased sealing means when said stem is threadably retracted from a substantially fully advanced position.