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:
Mar. 21, 1978
Filed:
Jan. 28, 1977
Paul G Szymaszek, Milwaukee, WI (US);
Vilter Manufacturing Corporation, Milwaukee, WI (US);
Abstract
A variable capacity rotary screw compressor driven by an electric motor and having an adjustable slide valve for varying compressor capacity is provided with a control system for adjusting the slide valve to regulate compressor capacity and thereby maintain a variable system condition, such as gas inlet or outlet pressure or temperature, within a predetermined range. The control system comprises first means including a current transformer for sensing changes in motor current as compressor capacity varies and a current converter connected to the current transformer for providing a first electrical signal proportional to compressor capacity. The control system also comprises means for sensing changes in the particular system condition being monitored and for providing a second electrical signal proportional thereto. The control system further comprises means including a proportioning relay for receiving and comparing the aforesaid first and second electrical signals and for providing a third signal to control operation of the adjustable slide valve to thereby regulate compressor capacity and maintain the system condition within a predetermined range.