JPH04282593A - Cartridge heater - Google Patents

Abstract

PURPOSE:To provide a cartridge heater where the quick heating is possible and the quantity of power consumption is small. CONSTITUTION:The electric insulator pipe 2 to cover a heating part 1 is constituted of a ceramic baked body of AlN. This cartridge heater can quickly heat an object, having high thermal shock resistance, and can save powre consumption.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cartridge heater that is used as a heating source in a wide range of product fields in various industries, and relates to a cartridge heater that can rapidly raise the temperature.

0002

[Prior Art] Cartridge heaters generally have a heating element formed by coiling an electric heating element around a rod-shaped or plate-shaped electric insulator, and after inserting this into an electric insulator pipe, a terminal is attached to one end of the pipe. It is manufactured by providing a section and sealing both ends of the pipe with an insulator. Alternatively, print a resistance pattern such as W or Mo-Mn on a ceramic green sheet,
This ceramic sheet with resistor printing is wrapped around the outside of a bar-shaped or pipe-shaped ceramic molded body, and this is baked at high temperature to produce a heat generating part, which is then inserted into an electrical insulator pipe. .

Conventionally, cartridge heaters are simple and highly safe, and have been widely used as heating sources in various industries. Conventionally, alumina has been used as the electrical insulator pipe of such cartridge heaters. Alumina insulator pipes have low thermal conductivity, so it takes time to raise the internal temperature in order to transfer heat from the internal heat generating part to the outside, and in order to obtain a constant amount of external heat radiation, the inner surface is heated to a high temperature. This makes it difficult to handle applications that require rapid heating. Furthermore, there was a drawback that a large amount of power was used for this purpose.

0004

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a cartridge heater that can rapidly raise the temperature and consumes less power.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the present invention is characterized in that an AlN sintered body is used as an electrical insulator pipe of a cartridge heater.

[0006]

[Operation] In order to rapidly raise the temperature of the cartridge heater, an electrically insulating pipe with high thermal conductivity may be used. This is because in order to transfer the heat from the heat generating part to the outside, it is necessary to conduct heat efficiently through the electrical insulator. The AlN sintered body used in the present invention has a high thermal conductivity of about 150 W/m·K, which is about 10 times that of alumina.

[0007] Furthermore, the AlN sintered body has high thermal conductivity, excellent heat uniformity, and high strength, so it has excellent thermal shock resistance.
Rapid heating is possible. Therefore, when an AlN sintered body is used as the electrical insulator pipe of the cartridge heater, the temperature can be increased much more rapidly than when alumina is used. Further, since the AlN sintered body has high thermal conductivity, the difference between the temperature inside the cartridge heater and the surface temperature is small, and the power density and amount of power required for heating are reduced.

The AlN sintered body used as the electrical insulator pipe of the present invention can be manufactured by the following method. A
Appropriate amounts of sintering aid and forming aid are added to IN powder and wet mixed. Depending on the shape, molding is performed using various molding methods such as extrusion molding, injection molding, and press molding. Further, when printing the resistor paste on a ceramic green sheet and performing integral firing, the green sheet is created by a sheet molding method. After molding and degreasing, sintering is performed at a temperature of 1750°C to 1950°C in a nitrogen stream. For example, if Y2 O3 is used as a sintering aid, a sintered body with high thermal conductivity of about 150 W/m·K can be obtained.

[0009]

[Embodiment] An embodiment of the present invention will be described below based on FIG. FIG. 1 shows an example of the configuration of a cartridge heater. Ni
- Prepare a heat generating part 1 made of a rod-shaped sintered ceramic body wrapped around a heat generating element made of Cr, and insert this heat generating part 1 into an electrical insulator pipe 2 made of AlN with an inner diameter of 8 mm and an outer diameter of 10 mm. Both ends of the pipe were sealed with insulator 3 to produce a cartridge heater. As Comparative Example 1, a cartridge heater with the same specifications except that the pipe 2 was made of alumina was manufactured.

10V to these two types of cartridge heaters
FIG. 2 shows the change in heater surface temperature over time when a current of 3 A was applied. As can be seen from FIG. 2, the cartridge heater using the AlN sintered body was able to raise the temperature about five times faster than the cartridge heater made using alumina. Furthermore, since alumina has low thermal shock resistance, it broke at 300°C under these conditions.

Further, the surface temperature of the electric insulator pipe is 2
The amount of power used by the heater until the temperature reached 50°C was measured. A
The cartridge heater using IN used approximately 40% less power than the cartridge heater using alumina.

0012

Effects of the Invention Since the cartridge heater of the present invention uses an electrically insulating pipe made of AlN, rapid heating is possible and the amount of power consumed can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention.

FIG. 2 is a graph showing the effects of the present invention.

[Explanation of symbols]

1 Heat generating part 2 Ceramic pipe 3 Insulator

Claims (1)

[Claims] 1. A cartridge heater comprising an electrical insulator pipe made of an AlN sintered body.