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. 07, 1997
Filed:
Jun. 20, 1995
Masato Kuroda, Tokyo, JP;
Yamatake-Honeywell Co., Ltd., Tokyo, JP;
Abstract
An electropneumatic positioner includes an electropneumatic converter, an pilot relay, an operating unit, and a sensor. The electropneumatic converter includes a yoke having central and side leg portions, a permanent magnet arranged on the central leg portion, a pair of coils for exciting the side leg portions to have opposite polarities, a nozzle embedded in one side leg portion to spray air having predetermined pressure, a stopper arranged on the other side leg portion, and a flapper arranged to be swingable on a fulcrum near the central leg portion and serving to change a nozzle back pressure by controlling the amount of air sprayed from the nozzle in accordance with a swing. The electropneumatic converter receives a duty signal, as a driving signal for the coils, which signal is obtained by converting a deviation between an input signal and a feedback signal into a duty. The flapper is set to be parallel to the yoke when the deviation between the input signal and the feedback signal is zero. The pilot relay receives a nozzle back pressure and amplifies an air pressure. The operating unit converts an output air pressure from the pilot relay into a mechanical displacement amount. The sensor detects the displacement amount obtained by the operating unit and generates a feedback signal.