Patent ID: 7905254
Filing Date: 2011-03-15
Classification: F16K,Y10T

Abstract:
1. A shut-off valve in which a valve seat is provided in a flow passage of a valve casing equipped with a fluid inlet and a fluid outlet, and in which a valve body, supported at a forward end of a valve operating shaft connected to electromagnetic opening/closing means and adapted to move axially with respect to the valve seat, is urged by a compression spring to be brought into contact with the valve seat, and is separated from the valve seat by the electromagnetic opening/closing means, wherein the valve seat is composed of a first valve seat portion formed on an inlet side of a valve hole at a center, and a second valve seat portion formed on an outlet side of the valve hole and of a smaller diameter than the first valve seat portion, wherein the valve body is composed of two valve body portions separably superimposed one upon the other, that is, a first valve body portion with a large diameter in contact with the first valve seat portion, and a second valve body portion with a small diameter in contact with the second valve seat portion, wherein the first valve body portion is formed of an elastic material, whereas at least a portion of the second valve body portion other than a remaining portion thereof in contact with the second valve seat portion is formed of a rigid material wherein a through-hole through which the valve operating shaft is passed is formed at a center of the first valve body portion, wherein the forward end of the valve operating shaft passed through the through-hole is connected to the second valve body portion, wherein, between the first valve body portion and the valve operating shaft, a first valve body portion moving means is provided, which is adapted to make mutual engagement at the time of valve opening to cause a central portion of the first valve body portion to move away from the second valve body portion, and wherein, at the position where the forward end of the valve operating shaft and the second valve body portion are connected together, a second valve body portion valve opening operation delaying means is provided, which, at the time of valve opening, delays the valve opening operation of the second valve body portion, and gives priority to the operation of moving the first valve body portion by the first valve body portion moving means, wherein the portion of the second valve body portion in contact with the second valve seat portion is formed of an elastic material as a valve seat contact portion, and the remaining portion thereof is formed of a rigid material as a main body portion, and wherein an outer peripheral portion of a base portion of the main body portion retaining the valve seat contact portion does not hinder circulation of a fluid having passed through the through-hole of the first valve body portion at the time of valve opening.