| 摘要 |
<p>A gate valve includes a valve body (106), a bonnet (62) for mounting on the body and a compressible seal (108) for location therebetween. A retainer (110) is inserted between the body and bonnet on an initial compression of the seal (108) by relative axial movement of the body and bonnet, the retainer maintaining a lesser degree of compression on the seal on release of the initial compression. The bonnet (62) has an enlarged end portion adjacent the body (106) which accommodates an axially-fast collar carried by a valve stem. Ribs (160, 162, 164) on the gate valve closure member (144) cooperate with bearing surfaces on the valve body. In order to prevent damage to the valve, an end cap (180) having a weakened portion (192) may be secured over the valve stem. <IMAGE></p> |
