Apparatus for detecting flow amount of fluid in passage

Abstract

An apparatus for detecting the flow amount of a fluid passing through a passage. The apparatus comprises a scroll chamber having a circular horizontal cross section and having an inlet opening defined in a tangential direction of the scroll chamber and an outlet opening defined at a substantial center portion of a bottom surface of the scroll chamber. The fluid is introduced through the inlet opening and discharged from the outlet opening. In the scroll chamber, a conically protruding member is provided on a substantial center portion of the top surface of the scroll chamber so as to be protruded vertically and downwardly along the axis of the scroll chamber. A spheral member encased in the scroll chamber is turned about the protruding member and along a wall of the scroll chamber in response to introduction of the fluid through the inlet opening. The flow amount of fluid is measured by detecting the number of turns of the spheral member. The scroll chamber has a conical portion whose diameter decreases toward the upper side and is arranged so that the spheral member is turned with it being brought into contact with the tapered surface of the conical portion. This provides an extremely stable detection of the fluid flow.