Patent ID: 8511337
Filing Date: 2013-08-20
Classification: F16K,G05D,Y10T

Abstract:
1. A flow rate controller comprising a proportional electromagnetic valve of a non-sliding type for adjusting a flow rate of a fluid which is a gas, a flow rate sensor for detecting the flow rate of the fluid, and a control circuit for controlling the proportional electromagnetic valve so that the flow rate detected by the flow rate sensor reaches a predetermined target flow rate of 11 to 100 L/min, wherein the proportional electromagnetic valve includes: a bobbin on which a coil is wound; a fixed core fixed in a hollow of the bobbin; a holder supporting the coil, the bobbin, and the fixed core; a movable core placed to face an end face of the fixed core and adapted to be attracted by the fixed core; a valve element fixed to an end face of the movable core; a body combined with the holder; a valve chamber formed in the body, in which the valve element is placed; a valve seat formed in the body and placed in the valve chamber in correspondence with the valve element; a lead-in path formed in the body to lead the fluid into the valve chamber; a lead-out path formed in the body to lead the fluid out of the valve chamber via the valve seat; an orifice formed immediately downstream of the valve seat in the body; and a spring urging the valve element in a direction to come into contact with the valve seat, the movable core is to be displaced by balance between an attractive force of the fixed core generated when the coil is excited by energization and an urging force of the spring, to adjust the position of the valve element with respect to the valve seat, and the orifice has an inside diameter set to a value of φ1 mm or more and an axial length set to a value having a ratio of from 0.1 to 0.6 inclusive to the inside diameter of the orifice, and the lead-out path has an inside diameter set to be larger than the inside diameter of the orifice.