DE3113006A1 - Temperature-regulation circuit for irons - Google Patents

Abstract

A temperature-regulation circuit for irons or the like having a sensor resistor which responds to the temperature of the iron heater or of the iron soleplate. In order that the temperature-regulation circuit responds quickly to temperature deviations or changes and thus ensures rapid regulation, and exact maintenance of the set iron temperature is ensured, a zero-voltage switch (10), which is known per se, is provided with a high-impedance NTC temperature sensor (11), which is connected in a bridge, and a potentiometer (12) connected in series thereto, in each case one resistor (14 or 15 respectively) being additionally connected in parallel with the NTC temperature sensor (11) and potentiometer (12). <IMAGE>

Description

Temperature control circuit for iron

The invention relates to a temperature control circuit for irons Od. Like. With an iron heater or soleplate to the temperature of the iron appealing sensor resistance.

Temperature control circuits for electric irons that use the Switch off the power supply to the iron heater as soon as a preset or preselected one Temperature is reached are well known. With such temperature control circuits bimetals are usually still used as temperature sensors, which can be turned by turning a temperature selector knob can be set according to the item to be ironed can. Such temperature control circuits have several disadvantages, essentially based on the fact that bimetals are relatively inert and precise Compliance with the well-chosen temperature for a particular bracket is not guaranteed is because when using metals, the control play is up to +/- 200C tolerance. Because of this.

large control play must therefore be based on the optimal ironing temperature large safety distance must be maintained.

The invention is based on the object of a temperature control circuit Specify for irons that respond quickly to temperature deviations or changes responds and thus ensures fast regulation and exact compliance of the set or selected temperatures, so that even for sensitive The most suitable and optimal ironing temperature for the fabrics is set very precisely and can also be adhered to.

The inventive solution to this problem is the characteristic Part of the claim can be found.

The proposed solution has the advantage that the tolerance while maintaining the ironing temperature is only +/- 10C. That achieved Control accuracy now makes it possible to find the one that is just tolerable for every type of fabric Adjust the ironing temperature as precisely as possible.

Such an ironing temperature provides for the type of fabric in question or fabric always the best ironing result in terms of smoothing. Further there is the possibility of making the ironing temperature selector or adjuster more user-friendly to design and arrange.

In the following, the 1Crfin (llar3rr based on an achaltunffaskizze explained in more detail.

The circuit diagram shows one for the purpose mentioned above particularly suitable two-position controller with superimposed proportional behavior, designed as a monolithically integrated eight PIN (1 to 8) zero voltage switch 10 is. For the purpose of temperature measurement or

detection is a high impedance switched as part of a bridge NTC temperature sensor 11 is provided for temperatures up to 3200C suitable and conveniently arranged in the central area of the soleplate is. An excessive bridge current is generated by a temperature sensor designed in this way avoided. A potentiometer 12 with a series connected to it serves as a setpoint transmitter Resistor 13. The NTC temperature sensor 11 and the potentiometer 12 is useful a resistor 14 or 15 connected in parallel, which is responsible for the linearization of the exponential NTC characteristic. The bridge voltage is an internal comparator fed in the zero voltage switch 10. The control pulses of a triac 16 with resistance 17 are only generated if PIN 3 is positive compared to PIN 4. One over one Resistor 18 connected to PIN 4, known staircase generator, causes the proportional behavior this circuit. By changing the resistor 18, the proportional influence can be varied. The generator frequency is determined via a capacitor 19. To achieve good control behavior, this two-point temperature controller is requires a high generator frequency. A resistor 20 is used at PIN 8 the zero voltage synchronization and the adjustment of the output pulse width. With a diode 21 is referred to, to which a resistor 22 is connected. In series a further capacitor 23 is located for this purpose. The reference numerals 24, 25, 26 identify further resistors, the resistors 25,26 in series and parallel to the potentiometer 12 and the NTC temperature sensor 11.

With the help of the temperature control circuit described, the ironing temperature according to the setpoints set on potentiometer 12 with a tolerance of +/- 100 almost exactly adhered to. To set the target temperature, you can also use one Potentiometer also slide switch or Push buttons are used. The temperature control circuit shown can be in the iron handle or in the terminal compartment of the iron. Blank page

Claims (1)

Claim temperature control circuit for iron or the like. with a temperature sensitive to the iron heater or iron soleplate Sensor resistance, characterized by a zero voltage switch known per se (10) with a high-resistance NTC temperature sensor (11) connected in a bridge and in series with this potentiometer (12) and one each parallel to the NTC temperature sensor (11) and potentiometer (12) connected resistor (14 or 15).