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:
Oct. 21, 1997
Filed:
Dec. 21, 1995
Toshiaki Iwabuchi, Yabutsukahonmachi, JP;
Benkan Corporation, Tokyo, JP;
Abstract
An improved vacuum exhaust valve is disclosed for vacuum-operated exhaust lines of chemical vapor deposition equipment, which includes a sheathed heater made of hollow metal tube spirally formed into a coil and heating wire inserted into the spiral tube, the sheathed heater being mounted to sealingly shroud a reciprocally disposed valve disk. The sheathed heater is provided inside a bellows that is mounted to shield the core valve portion against the flow of chemical vapor flowing through the valve disk. Also, the sheathed heater is vertically expandably disposed for synchronization with the vertical movement of the valve disk as the latter is driven by an actuator to move into abutting contact or away from a valve seat between an inlet port and outlet port. In addition, a thermocouple is mounted inside the sheathed heater for measuring the temperature of the latter and operatively connected to a temperature control device for controlling the sheathed heater. With this arrangement, the temperature of the bellows, valve disk and valve seat is kept at a predetermined stable temperature range so as to minimize adhesion or deposition of chemical substance to their surfaces.