CS244316B1 - Heating element especially for soldering guns with tip temperature automatic regulation - Google Patents

Abstract

The invention provides a design of a heating element bodies, especially for solders with automatic tip temperature control where temperature control is based on principle thermoelectric voltage sensor. Function a separate thermocouple here a connection at one of the heating element outlets. The resulting thermoelectric strains is captured in pauses between half-waves transformed and rectified network voltage, intended to power the heater telieska. Said heating element is can also be advantageously used in other applications with the need for a precise defined temperature. Typically, a suitable example is spray paint heating where defined course of temperature of its various parts is achieved by using several heaters bodies with a suitable set temperature.

Description

The invention solves a design of a heating element, especially for soldering irons with automatic tip temperature control, where the temperature control is based on the principle of a thermoelectric voltage sensor. The function of a separate thermocouple here is replaced by a joint on one of the heater outlet. The thermoelectric voltage generated here is sensed in pauses between the halfwaves of the transformed and rectified fly-off voltage intended to supply the heater.

Said solution of the heating element can be advantageously used also in other applications requiring a precisely defined temperature. Typically a suitable example is, for example, heating of the spray molds, where a defined temperature profile of the various parts thereof is achieved by using several heating elements with a suitable set temperature.

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The invention relates to a heating element intended, in particular, for soldering irons with automatic tip temperature control, wherein the automatic control is based on the principle of sensing thermoelectric voltage.

Previously known solders with automatic temperature control have a separate thermocouple in the front part of the heating element. Such a solution is demanding in design with the following disadvantages:

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—Necessity of use and appropriate mounting of a separate thermocouple - the issue of routing the thermocouple leads through a heating element - the necessity of using at least a four-core power cord.

SUMMARY OF THE INVENTION The invention is based on a design of a heating element in which a joint on one of the terminals of the heating element takes over the function of a separate thermocouple. Since this outlet is made of constantane and its own heating coil of cantalum, there is a necessary thermoelectric voltage at the connection point, which is sensed at pauses between the halfwaves of the transformed and rectified mains voltage intended to supply the heating element.

This solution brings the following advantages:

- simple design of the heater essentially corresponding to the design, but without temperature regulation - a two-core cord is sufficient - simple and easy replacement of the heater - the design of the ter16 urine eliminates the effect of thermal inertia and the problem of temperature overshoot Above the set border.

The attached drawing shows the design of the heating element.

The cantate wire heater spiral 3 is embedded in the three longitudinal holes of the pyrostatic tube 4. The constant wire wire 2 is embedded in the longitudinal surface groove of the pyrostatic tube 4 and is welded to the front outlet of the spiral 3, forming a thermocouple at the joint. in a stainless steel tube 1, the outlet 2 being supported on this tube over the entire length. When the temperature reaches the set temperature, the thermocouple T is intensively heated from the actual coil 3 and at the same time cooled to the surface temperature of the pipe 1. Due to the thermal gradient from the coil 3 through the thermocouple T to the surface of the pipe 1 the heating is switched off about 50-40 ° C before the set temperature. When the heater is switched off, the thermocouple T cools down rapidly until the heater is switched on again. As the temperature difference between the set surface temperature of tube 1 decreases, the on-off intervals become shorter until a steady-state condition is maintained where the surface temperature of the tube 1 is maintained with an accuracy of + 3% of the set temperature.

Said solution of the heating element can be advantageously used also in other applications requiring a precisely defined temperature. A typical example is the heating of the spray molds, where a defined temperature profile of the various parts thereof is achieved by using several heating elements with a suitable set temperature, and where the application of the above principle would result in structural simplification.

Claims (2)

SUBJECT Heating element, in particular for soldering irons with automatic tip temperature control, in which the temperature control is based on the principle of sensing the thermoelectric voltage, characterized in that the thermocouple (Tj is realized by a connection at the outlet of the spiral heater). rests on the trumpet (lj throughout its length. Heating element according to claim 1, characterized in that the outlet (2j) is of a constant wire and the heating coil (4) of a cantalum wire.