| 摘要 |
A butterfly valve disk is rotatably mounted within a passageway formed in the valve body and an annular seal fitted in the valve body projects within the passageway. A peripheral annular bearing surface formed on the valve disk is applied against the annular seal in the closed position. The valve disk carries a stop which is brought to bear on an internal surface of the valve in order to prevent rotational displacement of the valve disk beyond its normal position of closure. |
