Patent ID: 6302139
Filing Date: 2001-10-16
Classification: B01D,F17C,Y10T

Abstract:
An auto-switching sub-atmospheric pressure gas delivery system, comprising:(a) a multiplicity of gas panels, each of which comprises gas flow circuitry including a product gas flow line coupleable to a sub-atmospheric pressure gas source for flow of dispensed gas therethrough, a purge gas line coupleable to a purge gas source for flow of purge gas therethrough, a pressure-controlled flow regulator in the product gas flow line, and selectively actuatable valves for selectively and independently isolating each of the product gas flow line and the purge gas line in the gas flow circuitry of the panel to prevent flow of gas therethrough;(b) a product gas manifold interconnecting the product gas flow lines in each of the gas panels, for discharge of product gas from the product gas flow line of an active dispensing one of said gas panels;(c) a purge gas manifold coupled in gas flow communication with the product gas flow lines and with the purge gas lines in each of the gas panels;(d) a selectively actuatable evacuation driver arranged to exhaust gas from the flow circuitry of a non-dispensing one of said gas panels through said purge gas manifold; and(e) a central processing unit (CPU) arranged to selectively actuate:(1) in each of the gas panels, the selectively actuatable valves, and(2) the selectively actuatable evacuation driver, so that each of the gas panels operates sequentially, alternatingly and repetitively in operational modes including (I) an active dispensing operational mode in which gas from the sub-atmospheric pressure gas source is flowed through the product gas flow line to the product gas manifold, (II) a purging operational mode in which purge gas from the purge gas source is flowed through the purge gas line and into the product gas flow line and purge gas manifold, (III) an evacuation operational mode in which the purge gas line, product gas flow line and purge gas manifold are evacuated under action of the evacuation driver, and (IV) a fill transition to active gas dispensing condition operating mode in which the product gas flow line is filled from the product gas manifold with product gas deriving from another gas panel in an active dispensing operational mode, said active dispensing operational mode of said another gas panel is terminated, and the pressure-controlled flow regulator in the product gas flow line operates to regulate flow of product gas from the sub-atmospheric pressure gas source through the product gas flow line to the product gas manifold for re-initiation of (I) the active dispensing operational mode, at a rate avoiding the occurrence of product gas pressure spikes.