| 摘要 |
PROBLEM TO BE SOLVED: To provide a usage of ball valve capable of obtaining a desired flow rate over a long period by using a low-cost ball valve. SOLUTION: When the ball valve 64 performing the opening and closing by rotating a valve element 74 with a timing motor is fitted to an automatic developer, the angleθof valve opening is set so as to obtain the desired flow rate while considering an error produced in rotation angle of the valve element. The axis line 82A of a fluid passage 82 in the valve element 72 is deviated to the direction opposite to the error producing direction by the angleθwith respect to an axis line 80A of a fluid passage 80 in the valve element 72. By repeating the opening and closing of the ball valve, the flow rate gradually increases, reaches the maximum flow rate and, thereafter, gradually decreases. Therefore, the flow rate more than the prescribed flow rate can be secured over a long period. COPYRIGHT: (C)2004,JPO&NCIPI
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