CN1549653A - Self temperature control protective heater - Google Patents

Abstract

A self-temperature control protective heater is composed of a thick-film metallized substrate, a signal touch switch, a detection reference circuit, a control circuit, a signal amplifier circuit and a temperature setting circuit, wherein electric power is sent to the thick-film metallized substrate through the signal touch switch, an internal heating circuit of the thick-film metallized substrate is communicated with the signal receiving circuit to the temperature setting circuit, then the electric power is sent to a corresponding input end of the control circuit through the temperature setting circuit, the electric power of the power circuit is sent to the other corresponding input end of the control circuit through the detection reference circuit, and the output end of the control circuit is communicated with the touch end of the signal touch switch.

Description

Self temperature control protection heater

field of invention

The invention belongs to the field of electric heating technology, especially a self-temperature-controlled protection heater is formed by an innovative heating element and a temperature controller connected to it, which can instantly provide large energy, small area and high efficiency compared with traditional heaters. And it has the function of constant temperature self-protection.

Background technique

Heat energy is an indispensable energy source in the world. Natural heat sources such as geothermal heat and sunlight warm all kinds of organisms on the earth, so that our human ancestors discovered that we can use fire to cook food, drive away cold nights and wild animals, all rely on the benefits that heat energy brings to us.

Passively relying on natural heat sources to dissipate heat, or only lighting a fire to obtain heat, is no longer enough to satisfy the prosperous modern civilization. Nowadays, human beings have improved their ability to master energy technology, and can use scientific knowledge to industrially produce various heaters to make heat energy It is easier and more timely to obtain the required heat rating. With the popularization of artificial electricity all over the world, the most commonly used and mentioned heater often refers to an electric heating element that converts electric energy into heat energy. It is an important and necessary element in military affairs, industry or people's livelihood. The energy consumed by the heater accounts for a large proportion of the world's energy. It is everyone's goal to develop a high-efficiency and low-cost heating element.

There are various heaters on the market at present. However, for heaters powered by commercial power (alternating current), "electric heating wire" (nickel-chromium wire) is still the main type, as shown in the exploded view of the structure of the electric heating furnace in Figure 1, this type of electric appliance heated by electric heating wire 10, its electric heating wire A layer of metal heating body 30 must be placed outside the wire 10. The heated electric heating wire 10 passes through the surrounding space 20, heats the metal heating body 30, and then the metal heating body 30 contacts the heated object, although it has a low cost. , but there are many disadvantages as described below.

1. Low thermal efficiency

Since the heat transfer method can be divided into conduction, convection, radiation, and the conduction speed is conduction>convection>radiation in sequence, and because the heating wire is charged, it cannot directly contact the heated object, and the heat transfer method is mainly radiation. Convection is supplemented by heat convection between the gas in the surrounding space and the metal heating body, and then heat transfer to the metal heating body with radiation. The heat transfer path of the metal heating body cannot be as direct as the conduction method, and a lot of heat energy is dissipated to useless places. , and due to the low heat transfer rate, the temperature drop between the heating wire and the object to be heated is large. Considering that the heating wire will be burned, the heating wire cannot be increased blindly, so the power supply wattage is small and the time for the heated object to reach the required temperature Elongated, more heat energy will be dissipated to useless areas, and the efficiency will be lower. If another heating wire is wound on the insulator (mica sheet), and the mica sheet is used as an insulator on the outside, and attached to the object to be heated, this method is of course It can be in close contact, and will not leak electricity to the object to be heated, which meets the conductivity, but the mica sheet is not a good conductor of heat, and the heat transfer is still not easy.

2. Low security

Because the heating wire will burn red at high temperature, it is easy to generate a fire source and cause disasters, and it will burn the oxygen in the air, which will continue to cause a small amount of gas combustion pollution. The metal on the outer layer of the metal heating tube is easily heated and dissolved into the solution in a small amount, causing the drinker to gradually accumulate harmful metal substances.

In view of the above-mentioned various shortcomings of the existing heater, the inventor is actively researching ways to improve it, and after some arduous invention processes, he proposes the present invention.

Contents of the invention

The present invention aims to provide a self-temperature-controlled protective heater, which is made by the method of "thick film metalized substrate (Thick Film Metalized Substrate), which is printed and sintered with thick film material on a flat ceramic (ceramic A12O3) substrate. The conductor is used as the wire, the resistor Rx is used as the heating element, and the temperature effect resistor (Rs) is printed with conductive ink or low-ohm value ink. The ceramic substrate (which is a good conductor of heat) is used as the insulator and heat transfer medium, which can be directly pasted On the object to be heated, a large wattage can be provided instantly (as shown in Figure 2, the size can be increased to 100W). Since the ink is sintered at 850°C, it can withstand a temperature of around 500°C without deterioration, and can directly conduct heat energy to The thermal efficiency of the object to be heated is higher than that of the existing heater, which is the main purpose of the present invention.

Furthermore, the self-temperature-controlled protective heater of the present invention has a low impedance ink (Thick Film Paste), especially a conductor ink (Conductor Paste) with a high temperature change rate (Temperature Coefficient Resistance TCR), and the change can be used to correspond to the temperature. The change of temperature makes the temperature regulation very flexible, and the temperature sensor in the thermostat is on the same substrate, plus the control circuit can accurately control the temperature of the substrate not to exceed the set maximum temperature, so the design can make the heater instantaneous It can provide a large wattage. When the substrate itself reaches the maximum set temperature, it will protect itself first. When the temperature on the substrate reaches the temperature of the object to be heated and the temperature drops, the electric heating power will be turned on, so that the temperature on the substrate can be kept at a certain setting. In terms of temperature, when the object to be heated reaches the required temperature, a signal is fed back to jointly control the conduction of the electric heating power supply, so as to achieve the functions of providing large wattage, self-protection and constant temperature control in an instant, which is another purpose of the present invention.

Furthermore, the self-temperature-controlled protective heater of the present invention can achieve a protection setting below 500°C without any transformer in the overall control circuit, has a wide range of withstand voltage, and is not easy to burn out due to high pressure and high temperature, and can be connected in series by a filter type rectifier to rectify the AC power supply circuit, a signal touch switch to control the conduction of the heater (that is, the ceramic conduction electric heat generator described later), a ceramic heater (the heater Rx + temperature sensing resistor Rs are printed on the substrate ), a signal amplification circuit, a temperature setting circuit, a detection reference circuit, and a control circuit to form a complete thermal temperature control system, the detailed composition will be described later, and it has the characteristics of easy implementation, which is the core of the present invention Another purpose.

In addition, the self-temperature-controlled protection heater of the present invention, because the ceramic itself has heat transfer and temperature resistance, and is an insulator, it uses ceramics to directly contact the heated object, so there is no need to worry about leakage of electricity to the heated object, and it is extremely safe to use. High, this is another object of the present invention.

Description of drawings

As for the detailed structure, application principle, function and effect of the present invention, a complete understanding can be obtained by referring to the following descriptions made in accordance with the accompanying drawings.

Fig. 1 is an exploded view of the electric furnace structure of the existing electric heating wire heater.

Fig. 2 is a schematic diagram of the structure of the planar ceramic substrate of the self-temperature-controlled protective heater of the present invention.

Fig. 3 is an overall circuit diagram of the self-temperature-controlled protection heater of the present invention.

Fig. 4 is another implementation circuit diagram of the self-temperature-controlled protection heater of the present invention.

The number and name of each graphic component are compared

10...Heating wire 211...Bridge rectifier

20...Surrounding space 220...Signal touch switch

30...Metal heating body 230...Detection reference circuit

100...Thick film metallized substrate 240...Control circuit

101...Heating resistor 250...Signal amplifier circuit

102...Temperature sensing resistor 260...Temperature setting circuit

200...Thermostat 300...Single-chip IC

210...power circuit

Detailed ways

Fig. 1 is a diagram showing the structure of an electric heating furnace of an existing electric heating wire heater. The structure shown in this figure and the defects caused by its use are as mentioned above, and will not be repeated here.

Fig. 2 is a schematic structural diagram of the planar ceramic substrate of the self-temperature-controlled protective heater of the present invention, and its composition is as described above, and will not be repeated here.

FIG. 3 is an overall circuit diagram of the self-temperature-controlled protective heater of the present invention. It can be seen from the figure that it consists of a thick-film metallized substrate 100, a power supply circuit 210, a signal touch switch 220, and a detection reference circuit 230. , a control circuit 240, a signal amplifying circuit 250, and a temperature setting circuit 260, the control circuit 240 can be a single chip with matching functions, and the power circuit 210 can be rectified by a bridge rectifier 211 to output the alternating current For the overall required power supply, the circuit 210 can also be composed of a filter (commonly used components, not shown in the figure) connected in series with the bridge rectifier 211, so that the power of the power supply circuit 210 is sent to the thick film through the signal touch switch 220 The metallized substrate 100 , and the internal heating circuit of the thick film metallized substrate 100 . The signal amplification circuit 250 is connected to the temperature setting circuit 260, and then sent to the corresponding input terminal of the control circuit 240 by the temperature setting circuit 260, and the power of the power supply circuit 210 is sent to another corresponding input of the control circuit 240 through the detection reference circuit 230. terminal, and the output terminal of the control circuit 240 is connected to the touch terminal of the signal touch switch 220 . As for the internal heating circuit of the thick film metallized substrate 100, as shown in the figure, one end of a heating resistor 101 can be connected in series with a temperature sensing resistor 102 to the ground potential, and the signal amplifying circuit 250 is connected between the heating resistor 101 and the temperature sensing resistor 102. The other end of the heating resistor 101 is connected to the signal touch switch 220 , so that the bridge rectified power supply, the signal touch switch 220 , the heating resistor 101 and the temperature sensing resistor 102 form a series circuit.

Because heating resistance 101 printing ink TCR is low (≤1100PPM), temperature change is little to loop current change, though the TCR of temperature sensing resistance 102 has 1000PPM, resistance value is too small (with respect to test condition, make heating resistance 101 be 200 ohms, temperature The sensing resistance 102 (0.20 ohms) has little effect on the current, and the entire heating resistance 101 is connected in series with the temperature sensing resistance 102, and the overall resistance value changes little when the temperature changes. If a value can be set as a detection point in the voltage reference of each cycle of the sine wave, the detection point can be regarded as a constant voltage point per cycle (detection point setting circuit), and the current at this constant voltage point is fixed. It is not affected by temperature, and because the current at this constant voltage point (this constant voltage point is referred to as VL) is multiplied by the resistance value of the temperature sensing resistor 102, the signal sent to the signal amplifier circuit 250 (abbreviated as VRS), and due to the current at VL point Fixed, VRS will change with the change of temperature. When the temperature rises, the value of the temperature sensing resistor 102 increases, and VRS increases proportionally. Otherwise, the temperature decreases, and VRS decreases.

Then the VRS signal is amplified by the signal amplification circuit 205 to increase its discrimination ability, change the reference DC voltage reference of a comparator, and compare it with VRS at the VL point. When the temperature is higher than the set value, the controller 240 is here A signal will be received at the time point (the signal is referred to as H1). When the temperature is lower than the set value, the controller 240 will receive a signal L0 (the signal is referred to as L0) opposite to H1 at this time. According to the control circuit 240 When the input signal is detected at VL point is H1 or L0, and then output a signal to control the signal touch switch 220, if the control circuit 240 detects the signal L0 at the VL point, then trigger the switch 220 to keep the heating resistor 101 turned on , so that the heating resistor 101 continues to heat up to increase the temperature, and if the control circuit 240 detects the signal H1 at the VL point of the subsequent radio wave cycle, it will trigger the switch 220 to turn off, suspend the conduction of the heating resistor 101, and make the temperature no longer When it is raised and lowered, the temperature can be maintained and the effect of constant temperature control can be achieved.

In addition, because the single-chip IC of analog/digital (A/D) and digital/analog (D/A) is very mature, the above-mentioned three parts of the circuit can be put into the circuit 250, the temperature setting circuit 260, and the detection circuit 260. The point reference circuit 230, as shown in another implementation circuit diagram of Fig. 4, can be integrated in the same single chip IC (300) inside (the scope of the diagram mark 300 frame) to simplify the circuit, and the comparator (the diagram mark mark) of its temperature setting Op2) can also input a changed DC voltage reference and compare it with the amplified VRS, and the signal to turn on the heating touch switch 220 is implemented by a silicon-controlled rectifier (SCR), and the circuit 240 is at the VL voltage reference time point (notified by the I2 terminal of the circuit 240) to detect the above-mentioned voltage (into the I1 terminal voltage of the circuit 240), and then control the silicon-controlled rectifier (SCR) by the output terminal O1 of the circuit 240, and control the heating conduction, and The output terminal O1 of the circuit 240 can be designed by an internal program to conduct at least one small power conduction in each cycle to detect VRS, and then control the conduction of the silicon-controlled rectifier (SCR) according to the voltage (I1) to achieve constant temperature protection or constant temperature control. The I3 end of the circuit 240 is used to cooperate with the signal sent back by the temperature sensor circuit on the heated object. When I3=H1/L0 (H1, L0 see the above description) it represents that the heated object has reached or not reached the required temperature. I3 jointly controls the silicon-controlled rectifier (SCR), to achieve the self-protection of the maximum temperature of the heater and the control of the constant temperature of the heated object.

From the above, it can be seen that the self-temperature-controlled protective heater of the present invention can provide more energy instantaneously than traditional heaters, has a smaller area, and has constant temperature self-protection, and does not conduct heat through metal heating tubes, and will not cause metal damage. Dissolving into the solution harms the safety function of the human body, and has not been used publicly, which is in line with the provisions of the patent law.

The above descriptions are preferred specific embodiments of the present invention. If changes are made according to the conception of the present invention, and the functional effects produced by it do not exceed the spirit covered by the description and illustrations, all should be included in the rights of the present invention. within the required range.

Claims (5)

1, a kind of self-temperature control protection heater comprises:

A rectification circuit is responsible for providing DC power supply;

A thick-film metalliz substrate, wherein substrate is provided with two resistance, a heating resistor and a temperature sense resistance;

A signal touch switch, this signal touch switch can be electronic type or mechanical switch, forms series circuit with above-mentioned rectification circuit, heating resistor, temperature sense resistance, is responsible for the power supply supply of control heating resistor and temperature sense resistance;

A signal amplification circuit is responsible for acting on the ohmically voltage signal of temperature sense and is amplified;

A temperature setting circuit is used for design temperature;

A control circuit is responsible for detecting, is ordered this signal touch switch running, and

A detecting point reference circuit is responsible for providing the detecting time point to give this control circuit;

Wherein above-mentioned rectification circuit, switch, heating resistor, and temperature sense resistance form series circuit.

2, self-temperature control protection heater as claimed in claim 1; wherein signal touch switch, heating resistor, temperature sense resistance configuration become: signal touch switch one end is connected power supply; the other end connects heating resistor one end, and the other end of heating resistor connects temperature sense resistance.

3, self-temperature control protection heater as claimed in claim 1; wherein signal touch switch, heating resistor, temperature sense resistance configuration become: heating resistor one end is connected power supply; the other end connects signal touch switch one end, and the other end by the signal touch switch connects temperature sense resistance again.

4,, self-temperature control protection heater as claimed in claim 1; wherein signal touch switch, heating resistor, temperature sense resistance configuration become: heating resistor one end is connected power supply; the other end connects an end of temperature sense resistance, and the other end by temperature sense resistance connects the signal touch switch again.

5,, self-temperature control as claimed in claim 1 protection heater, described signal amplification circuit, temperature setting circuit, detecting point reference circuit can be integrated into a single-chip IC.

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