| 摘要 |
<p>A non-return valve comprises a valve body 1 which supports the upstream end of a valve closure means 2 formed by a sleeve of flexible but impermeable material. Closure support means 3 of a skeletal structure are positioned within the valve closure means 2. Forward flow through the valve is relatively unimpeded, but reverse flow causes the valve closure means 2 substantially sealingly to collapse upon the closure support means 3. In one of the principal applications of this non-return valve, the valve body 1 is the efflux duct of a fan.</p> |
