Abstract: A plastic gate valve including a plastic valve casing having a passage and a valve chamber therein; a spindle extending in the valve chamber and rotatably supported by the valve casing; a handle connected with the spindle and rotating it; and a plastic valve body engaged with the spindle and moving along an inner wall of the valve chamber in response to the rotation of the spindle whereby the valve body opens and shuts the passage. The valve body is made of heat-resistant rigid vinyl chloride resin and covered with rubber-like elastic material by means of vulcanization adhesion so as to be integral with the valve body.

Abstract: A gate valve comprising a valve casing having a valve chamber therein, a valve body moving up and down in the valve chamber so as to open and shut a valve passage, and a spindle engaged with the valve body and moving up and down in accordance with rotation of a handle so that the valve body moves up and down in the valve chamber. A cover is mounted above the valve chamber so as to seal and isolate the valve chamber. An upper threaded portion of the spindle passes through the cover. A guide ring having projections therearound is attached to the spindle. The projections of the ring are fitted into vertical lead grooves arranged on the inner wall of the cover.

Abstract: A diaphragm valve suitable for the food industry, including a valve body (1) and body caps (2) connected to opposite ends thereof in a detachable but water-tight manner. Sealing between the valve body (1) and the body cap (2) is provided by an annular groove (16) recessed on the end surface of the valve body (1) and/or the body caps (2) and packing rings (17) having an inner diameter corresponding to that of the valve body (1) and provided with an annular protrusion (18) fitted to the groove (16). By this sealing, a gap between the opposite surfaces of the valve body (1) and the body cap (2) is completely eliminated.