Large-caliber plastic butterfly valve

Abstract

The invention belongs to the technical field of butterfly valves, and particularly relates to a large-caliber plastic butterfly valve which comprises a valve body and a valve plate, a through hole used for being communicated with a pipe is formed in the valve body, a transition part used for placing a pouring gate is arranged on the through hole and connected with the inner wall of the through hole, the valve plate is movably arranged in the through hole and matched with the inner wall of the through hole in a sealed mode, the transition part is an inclined block arranged in the circumferential direction of the through hole, one side of the inclined block is smoothly connected with the inner wall of the through hole, and the inclined block inclines in the direction away from the axis of the through hole. According to the large-caliber plastic butterfly valve adopting the scheme, the inclined block is arranged on the through hole of the valve body to serve as the transition part and can serve as the position where the pouring gate is arranged during injection molding, so that after injection molding is completed, residual materials flowing down from the pouring gate are cut off on the inclined block, connection between the through hole and the valve plate is not affected, turning machining does not need to be conducted on the inner surface of the through hole of the valve body after injection molding, production procedures are reduced, and the production efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of butterfly valves, and more specifically relates to a large-diameter plastic butterfly valve. Background technique [0002] At present, the large-caliber butterfly valve of PVC water supply plastic is produced by injection molding, and in order to ensure the out-of-roundness of the inner hole of the main body of the butterfly valve during the injection molding process, it is generally necessary to set the gate of the injection runner at the inner hole in the middle of the valve body to avoid the impact of the injection molding melt The surface of the inner hole caused by the core is not round, so after the injection molding is completed, the residual material of the gate will be left on the inner hole wall, resulting in uneven surface of the inner hole, and the inner hole of the butterfly valve produced in this way is less round. Large, after the sealing structure is installed, the extrusion of the valve p...

AI Technical Summary

Problems solved by technology

[0002] At present, the large-caliber butterfly valve of PVC water supply plastic is produced by injection molding, and in order to ensure the out-of-roundness of the inner hole of the main body of the butterfly valve during the injection molding process, it is generally necessary to set the gate of the injection runner at the inner hole in the middle of the valve body to avoid the impact of the injection molding melt The surface of the inner hole caused by the core is not round, so after the injection molding is completed, the residual material of the gate will be left on the inner hole wall, resulting in uneven surface of the inner hole, and the inner hole of the butterfly valve produced in this way is less round. Large, after the sealing structure is installed, the extrusion of the valve plate and the sealing structure is not smooth, and the sealing performance of the butterfly valve cannot be satisfied; for example, a butterfly valve disclosed in Chinese patent CN207195680U has several grooves on the inner surface of the valve body, so The outer surface of the bush is provided with several protrusions matching the groove to release the pressure generated during the extrusion process of the disc plate and the bush. Although the form of the groove can solve the problem of the valve plate and the sealing structure Extrusion is smooth, but because the valve body is still a traditional structure, the gate must be set on the inner wall of the through hole in the middle of the valve body when injecting the valve body, so as to ensure the out-of-roundness of the through hole, and the gate needs to be cut off after the injection molding is completed , At this time, burrs and residues will be left on the inner wall of the through hole, which will damage the sealing performance of the butterfly valve. Therefore, a turning process is added to level the inner wall of the through hole, but this will cause the valve body to be processed too complicated, with high cost and high production efficiency. Low

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