Patent ID: 8262062

Claim:
A rotary valve comprising: a tubular housing having, at the side part, a port for communicating the inside and the outside thereof, and a tubular valve body which is contained within the housing rotatably in the circumferential direction and has, at the side part, an orifice hole capable of opposing to the port, wherein a flow channel area of the rotary valve formed by communicating the port and the orifice hole is changed by rotating the tubular valve body, wherein: the tubular valve body is configured to stop at a plurality of rotation stopping positions including a minimum rotation stopping position at which the flow channel area is minimized, a maximum rotation stopping position at which the flow channel area is maximized, and at least one intermediate rotation stopping position; an angle is formed between the tubular valve body at the minimum rotation stopping position and the tubular valve body at the maximum rotation stopping position; said at least one intermediate rotation stopping position equally divides said angle between the minimum rotation stopping position and the maximum rotation stopping position, such that each angle formed between two adjacent ones of said plurality of rotation stopping positions is the same; and each difference in pressure loss between two adjacent ones of said plurality of rotation stopping positions is the same, on condition that a passing flowing rate remains constant.