| 摘要 |
The present invention relates to a butterfly valve provided with an automatically opened auxiliary check valve therein. More specifically, a through-hole is formed to penetrate front and rear faces in a main disc of a butterfly valve. An auxiliary check valve is further installed in the through-hole. An inner end of one side shaft, which is connected to a shaft of a motor outside a valve body and rotates, is fixed to the rear face of one side of the main disc and is installed on a rotation shaft to open or close the main disc with the rotation of the motor. The other side shaft is fixed to the valve body on a fixed shaft to merely serve as a guide at the time of opening or closing the main disc. An auxiliary check valve operation plate to automatically close the auxiliary check valve when the main disc is completely closed is installed at the inner end of the fixed shaft. Accordingly, the pressure difference between the front and rear ends of the butterfly valve can be reduced in a short time, and it is possible to smoothly operate the valve. In addition, cavitation, which may occur at the rear end in a low orbit, can be prevented, and it is possible to drastically mitigate the impact applied to the entire butterfly valve. Accordingly, it is possible to drastically extend the service life of a product as well as each component, and it is possible to drastically reduce damage caused by cavitation noise. Particularly, it is possible to perfectly close the auxiliary check valve in a state where the main disc is completely closed without a separate stopper, and thus it is possible to drastically improve productivity and merchantability of a product and reliability of operation. |
