TEMPERATURE CONTROLLER OF ELECTROMAGNETIC INDUCTION HEATER AND ITS START SYSTEM

摘要

A temperature controller is used for an electromagnetic induction fluid heater including a heat generation member (12) made of a magnetic material and disposed in a fluid passage, a coil (13) disposed round the heating member and an RF current generator (5) for the coil (13), wherein the magnetic material of the heating member (12) makes a magnetic transition in which magnetization abruptly decreases when the temperature becomes high. This temperature controller comprises a current detector (31) for measuring a current flowing from the RF current generator (5) to the coil (13) to determine that the temperature of the magnetic material of the heating member (12) rises near the point of magnetic transition, and a current limiter (32) for limiting the current flowing through the coil (13) on the basis of the output from the current detector (31). When the temperature of the heating member (12) rises and reaches near the magnetic transition point, the detector (31) detects the rise in current and the current limiter (32) limits the increasing current. A method of starting the electromagnetic induction fluid heater described above comprises the following steps 1 to 4: 1. filling a fluid passage (11) with a fluid so that the heating member (12) is immersed in the fluid in the stationary state; 2. setting a predetermined temperature by a temperature adjuster (2) and supplying current from the RF current generator (5) through the coil (13); 3. pre-heating the heating member (12) and the fluid while limiting the current preferentially to the command of the temperature adjuster (2) when the temperature of the magnetic material rises near the magnetic transition point and the current flowing through the coil (13) increases; and 4. starting the fluid to flow through the fluid passage.