| 摘要 |
This invention relates to a closure for the outlet of a fan. A fan has an outlet opening 12 in a fan case volute 10 which is closed by a hinged flap 13, the weight of the flap being compensated by a counterweight arm 15. When the flap 13 closes opening 12, counterweight arm 15 is latched by latch 32 carried by spring 26 which must deform before the flap can open. Alternatively, the latch 32 is itself a resilient spring. The flap will only open sufficient static pressure is applied by the fan, and the resilient latch 25,32 prevent "flutter" which might be otherwise caused by outside air currents. |
