Changeover valve and gas transportation pipe system

Abstract

It is an object of the present invention to provide a changeover valve which is capable of preventing granular material from being crushed when the granular material is transported by gas through a pipe system, and more particularly a changeover valve which is capable of preventing grain from being crushed, broken, and chipped when the grain such as rice is transported by gas through the pipe system. It is another object of the present invention to provide a gas transportation pipe system for grain to which the changeover valve is applied. The changeover valve according to the present invention comprises: a valve disc in a cylinder shape including on a side part thereof a through passage which is connected to transportation passages on an upstream side and a downstream side and which is in an eccentric position deviated from a center of the cylinder; a casing for rotatably accommodating the valve disc therein; and a pair of discharge passages which are provided in the casing and connected to the through passage of the valve disc, and an inside diameter of an introducing passage of the changeover valve at an output end thereof is smaller than an inside diameter of the through passage of the valve disc and an inside diameter of the introducing passage in an output side part has a shape gradually decreasing in size toward the downstream side while an inside diameter of each of the pair of the discharge passages at an input end thereof is larger than the inside diameter of the through passage of the valve disc and an inside diameter of each of the pair of the discharge passages in an input side part has al shape gradually increasing in size toward the upstream side.