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:
Jan. 25, 2000
Filed:
Jul. 02, 1998
Tadao Watanabe, Ibaraki-ken, JP;
SMC Kabushiki Kaisha, Tokyo, JP;
Abstract
An analog voltage signal V.sub.A generated from a command signal generating device is converted to a PWM signal V.sub.B by a converter, and a drive transistor is ON/OFF controlled by the PWM signal V.sub.B, whereby a current is conducted to a heater. When the heater is heated, a fluid filling a chamber of the valve device is caused to expand, whereby a membrane approaches a nozzle and a flow amount of pressurized air introduced to the valve device is restricted. As a result, energy consumed by the drive transistor is reduced and energy efficiency is improved. Further, because the generated heat from the drive transistor is small, the fluid is not affected thereby and raised in temperature by the transistor heat, whereby the flow amount characteristics of the valve device can be controlled in a stable fashion.