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AssigneeSCI Systems, Inc.
InventorsDennis A. Sierk, Ronald R. DuRoss, Stephen G. Geist, Gregory L. Hays
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Gas flow control units in cabinets are connected to distribute process gas, on demand, to a plurality of utilization locations known as "tool" locations in a semi-conductor manufacturing plant. Each gas flow control cabinet has an exhaust duct which connects to an exhaust duct in the plant through which waste gases from the cabinet are exhausted by a fan to the atmosphere. Low flow alarm signals are generated if the exhaust flow is below a desired level. A programmable controller is provided for controlling the alarm function according to the size of the exhaust ducting from the plant so as to facilitate installation and operation of each cabinet in a variety of locations with different duct sizes.
A cabinet for housing process gas flow control means, said cabinet comprising, in combination, a housing, process gas flow control means in said housing, an exhaust outlet for said housing, an exhaust duct connected to said outlet, an exhaust fan for exhausting the gas from said housing to a remote location, measurement means for producing signals indicating the rate of gas flow through said exhaust duct, said measurement means including means responsive to operator control for setting a duct constant corresponding to the size of said exhaust duct, computing means for computing said flow rate as a function of the duct constant selected, and alarm means for comparing said signals with a pre-determined minimum level corresponding to a pre-determined gas flow and producing an alarm if said signals are below said level.
A method of installing process gas flow control cabinets in a plant having existing exhaust ducts of one or more sizes and fans to exhaust gas from said cabinets through said exhaust ducts, said method comprising, in combination, the steps of
Dependencies are inferred from the claim text.