Automatic temp. controller for shower mixer taps - has spindle driven by motor controlled by switching circuit and thermistor forming part of resistor bridge

摘要

The automatic temperature controller for shower mixing taps provides an accurate control which is independent of press. and temp. variations in the feed water supply lines. The mixer chamber (1) with hot and cold water inlets (2, 3) has a horizontal cylindrical control tube (6) which regulates the mixture to the outlet orifice (4). The control tube is rotated by a phase-controlled motor. The water temp. in the outlet pipe is detected by a thermistor probe (20). The thermistor forms part of a resistor bridge which also contains a potentiometer, controlled from the water temp. setting knob. With the aid of a zero voltage switch, comparator and thyristor circuit, the motor is controlled so that the correct hot water/cold water mix is always obtained.