| 摘要 |
PURPOSE:To prevent occurrence of clog or bite-in by making the tip of a three- way opening/closing valve furnished at the bottom outlet of a hopper for ready mixed concrete in the form of small wall thickness having a curvature, and furnishing a valve seat having a sharp tip at the inner wall surface of valve box and in the neighborhood of the bottom outlet from the hopper. CONSTITUTION:A three-way opening/closing valve 4a reducing its wall thickness gradually toward the tip 4c and having curvatures 4d, 4e is installed on a shaft 4a borne by a valve box 2a. On the other hand, a valve seat 2c with angle- shaped profile having curvatures 2e, 2f with which said tip 4c of three-way opening/closing valve 4a can contact or separate therefrom, is provided at the bottom of this valve box 2a, while another valve seat 17 having a tip 17a with which said curvature 4d of three-way opening/closing valve 4a can contact with a certain angle held, is furnished in the neighborhood of the bottom outlet 1a from the hopper 1. This eliminates risk of biting-in of aggregate in ready mixed concrete when the three-way opening/closing valve 4a is opened or closed, and clogging occurring with it can be prevented.
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