초록 ▼

A novel pressure swing type desiccant dryer for separating a gas fraction such as water vapor from a gas mixture, and a novel demand control system and method for controlling the operating cycle of such a dryer by variation of the time duration of a drying or a regeneration cycle portion in a manner

A novel pressure swing type desiccant dryer for separating a gas fraction such as water vapor from a gas mixture, and a novel demand control system and method for controlling the operating cycle of such a dryer by variation of the time duration of a drying or a regeneration cycle portion in a manner to satisfy prescribed conditions of energy transfer, as indicated preferably by temperature variations which occur over time in the drying and regeneration cycle portions.

대표청구항 ▼

In an apparatus for extracting a gas from a gas mixture wherein a flow control means is selectively operable to pass a stream of such a gas mixture in a given flow direction through a gas flow path which includes a desiccant mass in a repetitive sequence of gas drying cycles to adsorb such a gas fro

In an apparatus for extracting a gas from a gas mixture wherein a flow control means is selectively operable to pass a stream of such a gas mixture in a given flow direction through a gas flow path which includes a desiccant mass in a repetitive sequence of gas drying cycles to adsorb such a gas from such a gas mixture during each such gas drying cycle, and the flow control means being further operable between sequential ones of such gas drying cycles to direct a stream of gaseous medium in a reverse flow direction opposite said given flow direction through the desiccant mass to regenerate the desiccant mass by removing therefrom at least a portion of the product formed upon adsorption of such a gas by such a desiccant mass to thereby permit the desiccant mass to be effective for further gas adsorption in a subsequent gas drying cycle, a control system for limiting the duration of such a subsequent gas drying cycle comprising: a first detector means adapted to be positioned at a selected location in such a gas flow path; a second detector means adapted to be positioned in such a gas flow path upstream, with respect to said given flow direction, from said first detector means; said first and second detector means being operable to generate control signals in response to temperatures detected thereby in such a flow path; a control means operable to process control signals generated by said first and second detector means, and means for providing operative communication between said first and second detector means, respectively, and said control means; said control means including processor means which is operable to compute a first control parameter that is proportional to the difference between the control signal generated by said second detector means at initiation and at termination of such a regeneration cycle, and to repeatedly compute a second control parameter comprised of the difference between the control signal generated by said first detector means at initiation of such a subsequent gas drying cycle and the control signal generated thereby at intervals during said subsequent gas drying cycle; said processor means being further operable to repeatedly compare said first and second control parameters; said control means being further operable to actuate such flow control means to terminate said subsequent gas drying cycle when the magnitude of said second control parameter exceeds the magnitude of said first control parameter.