Title: Method of operating a control system

Abstract: A system having a vacuum source, a pressure source and a pressure operated control device. A pneumatically operated control unit is provided for increasing a pressure signal from the pressure source to the device as the value of the pressure of the pressure source increases from a first value to a second value and for thereafter decreasing the pressure signal from the pressure source to the device as the value of the pressure of the pressure source further increases from the second value thereof to a third value thereof, the control unit producing the signal in substantially the same manner but at different values for different levels of vacuum at the vacuum source thereof. The control unit can include a temperature responsive valve for substantially linearly changing the magnitude of the signal to the device in relation to a certain temperature range.

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Inventors: Brakebill, Harold G. (Concord, TN, US)

Application Number: 895775
Filing Date: 1978-04-12
Publication_date: 1979-10-02
Assignee: Robertshaw Controls Company (Richmond, VA)
Primary Class(es): 137/14 137/84, 137/85, 137/624.11
Other Classes:
US Patent Ref:

3819113	Jun, 1974	Puster	137/85.
4022237	May, 1977	Wertheimer	137/85.
4099539	Jul, 1978	Brakebill	137/84.

Other Refs:
Primary Examiner: Cohan, Alan
Assistant Examiner:
Attorney: Candor, Candor & Tassone