摘要 |
A flow rate controller is arranged such that a control circuit controls a proportional electromagnetic valve so that a flow rate detected by a flow rate sensor reaches a target flow rate. The proportional electromagnetic valve includes a coil supported in a holder, a bobbin and a fixed core, a valve element and a plate spring placed on a movable core, the valve seat, lead-in path, lead-out path, and orifice being formed in a body. The movable core is displaced by balance between an attractive force of the fixed core generated by excitation of the coil and an urging force of the plate spring, thereby adjusting the position of the valve element with respect to the valve seat to adjust the flow rate of a fluid. The orifice has an inside diameter set to a value of “&phgr;1 mm or more” and an axial length set to a value to have a ratio of “from 0.1 to 0.6 inclusive” to the inside diameter. The lead-out path has an inside diameter set to be larger than the inside diameter of the orifice.
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