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. 19, 1985
Filed:
Apr. 07, 1980
Robert E Alloca, Melville, NY (US);
Meyer I Mazon, Flushing, NY (US);
Grumman Allied Industries, Inc., Melville, NY (US);
Abstract
In a two-stage vacuum pumping system having a single drive motor powering both stages, a by-pass line connected between the container being evacuated and the interstage line between the two stages for relieving excess pressure in the interstage line during the initial pressure pull-down of the container. This reduces the load on the second stage pump and thereby lowers the power requirements of the drive motor. A pressure switch actuated solenoid valve in the by-pass line, which is in the open position during the pull-down procedure, is closed when the container is evacuated to a set-point pressure. When the by-pass line is closed off the two stages work together to pump down the container to a desired pressure below the pressure switch set point.