| 摘要 |
The present invention relates to a butterfly valve having a pressure difference reduction function when a disc is open. Especially, according to the butterfly valve of the present invention, a through-hole is punctured on a main disc of the butterfly valve to penetrate a front and a rear of the disc, and a subsidiary check valve is further installed in the through-hole. An inner part of a shaft in one side rotating by being connected to a shaft of a motor in the outer side of a valve body is fixed to a rear of one side of the main disc and is installed as a rotation shaft in order for the main disc to be opened or closed in response to the rotation of the motor. A shaft of the other side is fixed to the valve body as a fixed shaft in order to play a role of guide when the main disc is opened or closed. A subsidiary check valve operation plate making the subsidiary check valve be closed automatically when the main disc is completely closed is installed in an inner part of the fixed shaft. Therefore, the present invention can perform operation of the valve smoothly by mitigating pressure difference between a front part and a rear part of the butterfly valve in a short time, and also can prevent cavitation in advance which can occur at a rear part at a low orbit. Thus, the present invention can mitigate impact applied to the whole butterfly valve highly. Therefore, life span of not only each component but also the whole product can be extended sharply, and damage due to cavitation noise can be reduced sharply. Especially, because the subsidiary check valve can be closed completely under the state that the main disc is closed completely without a separate stopper, the butterfly valve can improve productivity, marketability and operation reliability of the product sharply. |
