A regulator is adapted to connect to a gas cylinder, particularly at a location upstream of a cylinder valve, and the regulator may include at least one of a filling slide component, oscillation damper, charge port, and a reset assembly. The regulator includes a body enclosing a cavity, and an inlet passage configured to attach to an associated gas cylinder and an outlet passage configured to attach to an associated cylinder valve, the inlet and outlet passages in selective fluid communication with one another. A flexible diaphragm/bellows is interposed between the inlet and outlet passages. A poppet assembly is located between the inlet and outlet passages that selectively seals with a poppet seat to regulate fluid flow between the inlet and outlet passages.

A modified vacuum actuated valve assembly and sealing mechanism is provided for improved sub-atmospheric flow stability characterized by the absence of delivery pressure spikes and flow excursions. The valve assembly includes a non-stationary thermoplastic seat and a stabber. The stabber is characterized by a top portion having a circular periphery designed to mechanically engage and disengage with an inner sealing surface of the thermoplastic seat. The sealing surface is coined to eliminate surface irregularities contained therein, thereby producing a relatively smooth coined mating inner sealing surface for the circular top portion of the stabber. The valve assembly also includes a modified bellows capable of fine tuning the delivery pressure of the valve assembly.

A modified vacuum actuated valve assembly and sealing mechanism is provided for improved sub-atmospheric flow stability characterized by the absence of delivery pressure spikes and flow excursions. The valve assembly includes a non-stationary thermoplastic seat and a stabber. The stabber is characterized by a top portion having a circular periphery designed to mechanically engage and disengage with an inner sealing surface of the thermoplastic seat. The sealing surface is coined to eliminate surface irregularities contained therein, thereby producing a relatively smooth coined mating inner sealing surface for the circular top portion of the stabber. The valve assembly also includes a modified bellows capable of fine tuning the delivery pressure of the valve assembly.