| 摘要 |
<p>A method of forming an injection moulded lining on a valve body comprises the step of defining a cavity having a main portion which when filled with lining material forms the desired lining, and an extension portion continuous with an edge of the main portion. Lining material is injected into the extension portion until the cavity is filled. Any sprues produced by the injection are on the tab formed by the material in the extension portion and not on the lining proper. Thus, there is no danger of damaging the lining as sprues are removed, and they do not cause local stress in the lining.</p> |
