| 摘要 |
<p>At least one of a pair of valve members which control the flow in a valve is composed substantially of silicon carbide (SiC). Preferably, the silicon carbide valve member is produced by the Lagan SiC process. It is possible to use a single silicon carbide valve member cooperating with a valve member of conventional ceramic material, or both cooperating valve members may be made of silicon carbide. Preferably, materials of different surface hardness are used for the cooperating valve members. In addition, one of the cooperating valve members preferably is softer and has a less smoothly polished surface than the other valve member. The silicon carbide material has a low friction coefficient even in the absence of lubrication and does not give rise to excessive adhesion between pieces of high surface finish and thus ensures the maintenance and the smoothness of operation for long periods of time with respect to the known ceramics.</p> |
