| 摘要 |
<p>Ball-cock comprises a ball sealingly encased in a cast body; an inlet and an outlet duct both of which adapted to be coupled to a (pipe)line and connected to the ball. The casing is made of a synthetic rubber, being cast as a single-piece component about the ball which is made of harder material than the casing e.g. a nylon or a polyurethane. The coefft. of thermal expansion of the ball is at least equal to that of the cast body. The ball-cock is made up of the smallest possible number of components, can therefore be simply and inexpensively mfd.</p> |
