Apparatus for detecting flow amount of fluid in passage

An apparatus for detecting a flow amount of a fluid, comprising:

• a body;
• a scroll chamber defined in said body, said scroll chamber having a circular horizontal cross section and having an inlet opening defined in a tangential direction of said scroll chamber and an outlet opening defined at a substantially center portion of a bottom surface of said scroll chamber, the bottom surface located downstream of the inlet opening, said fluid being introduced through said inlet opening and discharged from said outlet opening, said scroll chamber having a conical portion whose diameter is decreased toward an end of the chamber having the inlet opening and said inlet opening being defined in the tangential direction of said conical portion;
• a protruding member provided on a substantially center portion of a top surface of said scroll chamber so as to be partially protruding downstream along the axis of said scroll chamber but positioned at a distance removed from the outlet opening;
• a spheral member encased in said scroll chamber so as to turn about said protruding member and along a wall of said scroll chamber in response to introduction of said fluid through said inlet opening, said turning spheral member being brought into contact with the wall surface of said conical portion wherein an axial component of force on the spheral member due to the introduced fluid maintains the spheral member in stable motion along the bottom chamber surface and out of registry with the inlet opening;
• and
• a detecting unit for detecting the number of turns of said spheral member to measure a flow amount of said fluid.