公开(公告)号：US3556142A

公开(公告)日：1971-01-19

申请号：US3556142D

申请日：1969-05-13

Applicant: UNITED AIRCRAFT PROD

Inventor： SABIN LE ROY J ,  HUGHES PAUL R

IPC: F04D29/46 ,  F16K17/30 ,  F01B25/00

CPC classification number: F16K17/30 ,  F04D29/464 ,  Y10T137/7869 ,  Y10T137/86019

Abstract: Apparatus in a heat transfer system or the like. The open end of a duct normally supplied with air at high flow rates is controlled by a valve biased to a position of minimum restriction. Under conditions of high airflows, a created pressure difference moves the valve toward a position of maximum restriction. A fan, located in the duct to induce air flow in the absence of the normal supply, is protected thereby from damage caused by excessive windmilling.