Modified vacuum actuated valve assembly and sealing mechanism for improved flow stability for fluids sub-atmospherically dispensed from storage and delivery systems

A vacuum-actuated valve assembly (10), comprising:

• a modified bellows (13) defined at least in part by an enclosed chamber (18) sealed to isolate said chamber (18) from an outside region (14) surrounding the bellows (13), said bellows (13) comprising side regions (31) configured to longitudinally expand in response to a predetermined vacuum condition surrounding the outside region (14) of the bellows (13), said bellows (13) having a top portion threadably engaged to a port body (21) along an outer diameter of the bellows (13), and said bottom portion of the bellows (13) substantially defined by a contact plate (19);
• a pin (17) having a top end extending towards the bottom portion of the bellows (13) and a bottom end extending through an opening (28) of a stationary thermoplastic seat (11) and an opening (29) in a top portion (16) of a stabber (12) to contact a surface of the stabber (12);
• the stationary seat (11) consisting essentially of a thermoplastic material and characterized by the absence of elastomeric material, said stationary seat (11) comprising the opening (28) extending from an outer surface (27) of the seat (11) to an inner sealing surface (26) of the seat (11), said seat (11) further comprising a grooved region (15) extending along said inner sealing surface (26) of said stationary seat (11);
• the stabber (12) comprising a body portion (30)and the top portion (16) each of which is situated within the interior of the stationary seat (11), said interior of the stationary seat (11) defined, at least in part, by an inner diameter greater than an outer diameter of the top portion (16) and an outer diameter of the body portion (30) thereby creating a passageway (20) between the stabber (12) and the seat (11);
• wherein said top portion (16) of the stabber (12) is abutted against said grooved region (15) of the stationary seat (11) so as to be maintained in mechanical engagement therealong when the bellows (13) is in a non-expanded state, said engagement creating a seal that blocks the passageway (20) and prevents the flow of fluid therethrough, thereby creating a closed configuration of the valve assembly (10);
• wherein expansion of the bellows (13) along the side regions (31) in a longitudinal direction in response to the predetermined vacuum condition surrounding the outside region (14) of the bellows (13) increases the length of the side regions (31) of the bellows (13) by an incremental amount sufficient to urge the contact plate (19) downward against the top end of the pin (17), thereby causing said bottom end of the pin (17) to push down against the surface of the stabber (12) and push the top portion (16) of the stabber (12) away from the grooved region (15) along the inner sealing surface (26) of the stationary seat (11), thereby mechanically disengaging the seal to unblock the passageway (20) and create a gap between the top portion (16) of the stabber (12) and the inner sealing surface (26) of the stationary seat (11) to create an open configuration of the valve assembly (10) for the fluid to pass therethrough.