Modified vacuum operated valve assembly and sealing mechanism for improved flow stability for fluids dispensed below atmospheric pressure from storage and delivery systems

摘要

Modified vacuum operated valve assemblies and sealing mechanisms are provided for improved subatmospheric flow stability characterized by the absence of delivery pressure spikes and flow fluctuations. The valve assembly includes a non-fixed thermoplastic seat and a stabber. The stabber features an upper portion with a circular perimeter that is designed to mechanically engage and disengage with the inner sealing surface of the thermoplastic sheet. The sealing surface is coined to remove surface irregularities included in the sealing surface, thereby creating a relatively smooth coined mating inner sealing surface for the circular upper portion of the stabber. The valve assembly also includes a modified bellows that can fine tune the delivery pressure of the valve assembly.