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:
Jul. 28, 1998
Filed:
Apr. 01, 1997
Tamami Takahashi, Tokyo, JP;
Yuichi Usami, Kanagawa-ken, JP;
Ebara Corporation, Tokyo, JP;
Abstract
A water hydraulic proportional control valve comprising: a valve body having a supply port, a control port and a return port; a spool axially movably disposed in the valve body for changing a direction of the working fluid and a flow rate of the working fluid; a direct driving mechanism which directly converts electric signals into a driving force for moving the spool, the valve opening of the control valve is controlled by means of a proportional control of the amount of a displacement of the spool from a neutral position thereof toward one direction or another according to an input signal supplied to the direct driving mechanism; spool side chambers provided on both sides of the spool; and drain channels formed in communication to each of the spool side chambers; wherein a water is used as the working fluid, and a flow passages is provided for introducing a pressurized fluid into said spool side chambers, whereby water filling the chamber is constantly replaced by a fresh water thereby preventing generation of microorganisms and decay of the water.