The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 25, 1985
Filed:
Dec. 10, 1982
Richard L Kenyon, Irvine, CA (US);
Calvin E Kempton, Laguna Hills, CA (US);
Parker-Hannifin Corporation, Cleveland, OH (US);
Abstract
A hot air modulating valve for mixing hot air with cold air flowing in a duct, the modulating valve having a torque motor operated pilot valve to position the modulator valve to maintain a predetermined temperature of the hot air-cold air mixture. The temperature of the mixture is sensed by a thermistor which in conjunction with a tri-mode (proportional plus integral plus derivative) electronic controller which provides an input current signal to the torque motor to position the modulator valve in proportion to the input current signal, produces zero steady state errors, and provides an anticipation effect to compensate for control system time lags. The controller has auxiliary inputs which when exceeding predetermined values switch the air mixture temperature at the thermistor to a lower setting. The modulating valve has a relatively low gain during the initial portion of its opening stroke to improve system dynamic stability and has a position feedback to the torque motor operated pilot valve.