JPH05114460A - Heating apparatus - Google Patents

Abstract

PURPOSE:To reduce the number of wires for operating a heating apparatus to introduce electric power to a heating resistor by externally measuring the specific level of temperature in low temperature and very low temperature zones where a heat inflow from the outside causes a problem. CONSTITUTION:A heating apparatus 1 and a heater control section 2 are connected to each other via two wires 31 and 32, and a control circuit section 23 selectively actuates a temperature measurement circuit section 21 for measuring heater temperature, and a power circuit section 22 for introducing power to the heating apparatus, depending upon the level of the measured temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to controlling the electric power introduced into a heating resistor by measuring the temperature of a specific object from the outside in a low temperature range or an extremely low temperature range where heat inflow from the outside is a problem. The present invention relates to a heater that also functions as a temperature control sensor.

[0002]

2. Description of the Related Art Generally, when a heating resistor is energized and heated, a temperature sensor separately provided measures the temperature of the object to be heated and controls the electric power introduced into the object to be heated.
It secures the required temperature. In this case, as a matter of course, two sets (4 or more) of wirings for introducing electric power to the heating resistor and wirings for temperature measurement are required. This is sufficient for a heating operation under a general condition in an electric furnace using a nichrome wire or the like as a heating resistor, or a heater for home appliances, and there is almost no problem.

[0003]

According to the above-mentioned conventional method, the temperature of a specific object is measured from the outside in a low temperature region or an extremely low temperature region where heat inflow from the outside is a problem, and the temperature is applied to the heating resistor. It becomes a problem when operating and controlling the introduced power of. The reason is that it is necessary to suppress unnecessary heat inflow from the outside as much as possible in the low temperature region or the extremely low temperature region.
Therefore, it is necessary to reduce the number of external wirings to the heating resistor in the low temperature region or the extremely low temperature region as much as possible. This is also taken into consideration when controlling the temperature of a specific object in a vacuum and in a high vacuum from the outside by using a heating resistor. In this case, if the number of terminals introduced from the outside is small, the workability in the vacuum container becomes easier,
This is because it is advantageous in many points. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heater that reduces the number of wires to the heating element.

[0004]

In order to solve the above problems, the present invention uses the heater itself as a temperature sensor for measuring the temperature of an object to be heated and reduces the number of wirings. In this case, the material of the heating element is required to have a property that the resistance value changes linearly (linear function) or with a simple function with temperature in the temperature range of use, and therefore, platinum, nickel, molybdenum and Tungsten or the like is used. In addition, as the configuration of the heating resistor, it is required that heat exchange with the object to be heated is extremely fast and a thermal equilibrium state be easily achieved in order to function sufficiently as a temperature sensor as well as a heating element. Therefore, in the present invention, a heating resistor is formed in the form of a film on a ceramic such as alumina having a relatively large thermal conductivity at the temperature at which it is to be used as a heater.
Furthermore, this heating heater is connected to a heater control unit that measures temperature and outputs power by two wires,
The heater control unit measures the temperature of the heating heater and introduces electric power corresponding thereto at appropriate time intervals, and controls the temperature of the object to be heated to an appropriate temperature required.

In the heater control section, energization to the heater and temperature measurement are alternately switched at preset time intervals. Therefore, since the same wire can be used for both the temperature measurement of the heater and the introduction of electric power, the number of wires can be reduced.

[0005]

Embodiments will be described below with reference to the drawings. Figure 1
Shows the connection relationship between the heater 1 and the heater control unit 2 according to the present invention, in which the two heaters 31 and 32 are connected to the heater control unit. Then, the heater control unit measures the temperature of the heater, and the power supply circuit unit 22 for supplying electric power to the heating heater corresponding to the measured temperature.
And a control circuit unit for switching the temperature measurement and the electric power introduction at appropriate time intervals and also controlling the whole.
23 and a changeover switch 24.

The heater is made of a ceramic heater. The ceramics heater itself is well known, so although not shown in the drawing, 96% alumina
On the green sheet, pattern-print a heating resistor with a thick film printing method using platinum paste, and then print at about 1600 ℃
It was formed by firing at. The platinum paste used was a mixture of platinum powder with about 16% by weight of alumina powder.
It was prepared by adding an organic vehicle. In the ceramic heater after firing, the outer shape of the substrate is 8 cm in length, 4 cm in width,
With a thickness of 0.635 mm, the platinum heating resistor has a total length of about 10
It was formed with a thickness of 0 cm, a film thickness of about 16 μm, and a film width of about 0.4 mm, and the resistance value was about 60 Ω at room temperature. Furthermore, this ceramic
The heater is fixed in a copper container for the heater using an adhesive containing alumina, and the copper container for the heater has an outer length of 84 mm, a width of 44 mm, a height of 6 mm, and a copper thickness of 2 mm. there were.

FIG. 2 shows an experimental apparatus used to test the characteristics of the heater, and the heater is constructed so as to have a low temperature in vacuum. That is, the heater 1 was fixed on a jig 33 made of copper having good heat conductivity, and the fixed portion was placed in the vacuum container 34. Also, the opposite end of the copper jig is cooled with liquid nitrogen in order to cool the heater to a low temperature.
It was inserted into an outer container 36 filled with 35. Reference numeral 37 is a thermocouple for measuring the temperature in the experiment, 2 is the above-mentioned heater control unit, which is connected to the heater 1 by wires 31 and 32. As a result, the heater will have a vacuum of about 0.1 to 0.001 To.
At rr, the surface temperature was kept at about 80K with no power input. The surface temperature of the heater is measured by the thermocouple 37.

FIGS. 3 and 4 show the experimental results concerning the heater according to the present invention, and FIG. 3 shows the value of the current flowing from the heater control section to the heater when switching between temperature measurement and power introduction. Shows the change of. That is, the temperature is measured by applying a current of about 30 mA to the heating heater for about 0.5 seconds, and the heating operation of the heating heater is performed by applying a current of about 1.5 A (heating amount of about 2.5 W at a temperature of 80 K) for about 3 seconds. It is done by things. If the temperature measured during these operations reaches a value above the upper limit set temperature (100 K in this experiment), power is not introduced for the heating operation of the heating heater and the temperature is measured. When the temperature reached the lower limit set temperature (98 K in this experiment), the exothermic operation was performed again for about 3 seconds. Figure 4 shows the above set temperature
The change of the surface temperature of the heater when the ON-OFF operation of the electric power introduction to the heater is performed. As a result,
The surface temperature could be controlled between the upper limit of about 100K and the lower limit of about 97K.

[0009]

As described above, according to the present invention, the heating resistor itself of the heater is also used as the temperature sensor for temperature control, so that the following effects can be obtained. Since the temperature measurement and the power introduction can be done with the same wiring, only two wirings for the heater are required. When the above heater is used in a low temperature range or an extremely low temperature range, the number of wirings is small, so that unnecessary heat inflow from the outside can be reduced. When used in a vacuum or a high vacuum where airtightness with the outside is a problem, the number of introduction terminals to the vacuum container can be reduced, which is advantageous in many aspects such as workability and operability. Also, by reducing the number of terminals, etc., vacuum break (leakage) with the outside
The risk of can also be reduced. Ceramics such as alumina, green sheet substrate,
It can be mass-produced at low cost by producing it on a ceramics sintered substrate by a thick film printing method. In addition, heaters of various shapes such as circular, square, donut-shaped, crescent-shaped, and pipe-shaped can be manufactured according to the application. A heater having an appropriate response speed can be configured by using ceramics having a large thermal conductivity or ceramics combined with a metal having a large thermal conductivity.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a heater according to the present invention.

FIG. 2 is a diagram of an experimental apparatus used to test the characteristics of a heater.

FIG. 3 is a time chart explaining each switching operation of temperature measurement and electric power introduction.

FIG. 4 is a diagram showing a change in surface temperature of the heater when an ON-OFF operation for introducing power to the heater is performed.

[Explanation of symbols]

 1 Heater 2 Heater control unit 21 Temperature measurement circuit unit 22 Power supply circuit unit 23 Control circuit unit 24 Changeover switch 31, 32 Wiring 33 Copper jig 34 Vacuum container 35 Liquid nitrogen 36 Container 37 Thermocouple

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Shimizu Kenji Shimizu 5310 Sangejiri, Kumagaya-shi, Saitama Chihuabu Cement Co., Ltd. Huain Ceramics Division (72) Ryozo Akihama 5310 Mikkaji, Kumagaya, Saitama Chichibu Huain Ceramics Division, Cement Co., Ltd. (72) Inventor, Tomio Okada, 5310, Sangejiri, Kumagaya, Saitama Prefecture Chichibu Sentence Co., Ltd., Huain Ceramics Headquarters, Chikabu, 5310, Chikaji, Abo, Kumagaya, Saitama 5353 Address: Huain Ceramics Headquarters, Chichibu Cement Co., Ltd. (72) Inventor, Osamu Mochida, Osamu, Kumagaya City, Saitama Prefecture, 5310 Address: Chichibu Cement Corporation, Huain Ceramics Headquarters, (72) Masanobu Ichikawa, Kumagaya, Saitama 5310, Mikkajiri Se in the Instrument Co., Ltd. off Ain ceramic try this portion

Claims (4)

[Claims] 1. A heating heater characterized in that the heating resistor also serves as a temperature sensor for controlling the heat generation of the heating resistor itself. 2. The heater according to claim 1, wherein the heater is used in a low temperature region and an extremely low temperature region where heat inflow from the outside poses a problem. 3. The heater according to claim 1, wherein the heater is used in a vacuum or a high vacuum where airtightness with the outside is a problem. 4. The heater according to claim 1, wherein a heating element is formed on the ceramic in order to improve thermal contact with the object to be heated.