JPS634503Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an electric heating device in a hot isostatic pressing device.

Pressure sintering. A small hot isostatic press device (hereinafter abbreviated as HIP device) used for processes such as diffusion bonding.
The demand for has increased rapidly in recent years,
In order to minimize equipment costs, most HIP equipment uses a heating device consisting of a heater that is operated by a single power supply and control device. It is quite difficult to heat uniformly regardless of the temperature.

This is because the mode of heat transfer in the furnace varies considerably depending on the two parameters in hot isostatic pressing, namely pressure and temperature. For example, at high temperature and low pressure, heat transfer is mainly due to radiation. On the other hand, at low temperatures and high pressures, heat transfer by convection plays a major role, so there is a big difference between the two.

Therefore, it has been extremely difficult to ensure heat uniformity over the entire range of 100 to 2,000 atm and 1,000 to 2,000° C. using a heater with a single control and single power supply system.

This invention eliminates the defects of conventional HIP equipment of this type, lowers equipment cost and improves operating economy, and also ensures heat uniformity despite using a single control and single power supply system. It was devised with the aim of making it possible to do this, and in particular, the heating device for heating the processing chamber of the HIP device is equipped with an electric heater made of a material with a positive temperature coefficient of resistance. The electric heater is configured to be supplied with power from a single power source, and the electric heater includes a main heater section mainly arranged around the processing chamber, and a main heater section arranged below the processing chamber. , is characterized by a configuration in which an auxiliary heater part having a higher resistance than the main heater part is connected in parallel, and as the temperature in the upper part of the processing chamber increases, the resistance of the main heater part increases accordingly. The amount of heat generated in the auxiliary heater section increases relatively, and as a result, the temperature in the lower section rises in a self-balancing manner, resulting in excellent heat uniformity, thus achieving the desired purpose. This led to the conclusion that

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a high-pressure vessel, in which a capped cylindrical heat insulating layer 2 and a hearth 3 are disposed, and both members 2 and 3 define a processing chamber 4.

As a heating device for heating the processing chamber 4, an electric heater that is supplied with a single power source and has a single control method is used. A cylindrical main heater section 5 mainly arranged around the main heater section 5 and a processing chamber 4.
A cylindrical auxiliary heater section 6 arranged at the lower part of the
It is made up of.

The material used for the above-mentioned electric heater must have a positive temperature coefficient of resistance near normal operating temperatures and a working temperature range of 500 to 2000°C, and a suitable material is molybdenum. Examples include graphite.

The main heater section 5 and the auxiliary heater section 6 are made of a plate-like or cylindrical body made of graphite, for example, and vertical slits are cut alternately at appropriate intervals from the upper and lower edges thereof. By doing this, a plate or cylinder having a zigzag surface is formed, and in the case of a plate, this is arranged in a cylinder shape,
In addition, the cylindrical body is configured as a cylindrical heating element having a zigzag surface, and is shaped so that it can uniformly heat the object placed on the hearth 3 from around it. It is preferable.

Both heater sections 5 and 6 are connected in parallel so that a single power source can be supplied as shown in FIG.

Therefore, in the example shown in FIG. 1, the auxiliary heater section 6 is arranged concentrically inside the lower end portion of the main heater section 5,
In addition to this, the device example of the present invention also has a third
The structure shown in FIG. 3 and FIG. 4 may be used, and the structure shown in FIG. The structure shown in FIG. It has a well-arranged structure.

What these examples have in common is that the main heater section 5 surrounds the object to be processed mounted on the hearth 3 from the entire side circumference, while the auxiliary heater section 6 surrounds the object to be processed mounted on the hearth 3. Both heater parts 5 and 6 are arranged at the lower part in order to ensure heat uniformity, which will be described later.
They agree that it is working.

It should be noted that when comparing the electrical resistances of the main heater section 5 and the auxiliary heater section 6, the former is small and the latter is large, and the heating capacity of the main heater section 5 is much larger. .

A specific example of the structure of both heater parts 5 and 6 is as follows:
Main heater part 5 has a diameter of 15 mm and a length of 405 mm.
By connecting 18 graphite round rods in series in an arrangement that divides the periphery of the processing chamber 4 into 18 equal parts,
A heater with a total resistance of about 0.501Ω is formed, while
The auxiliary heater part 6 has a diameter of 5 mm and a length of 105
A heater with a total resistance of 1.886 Ω is formed by arranging 30 mm graphite round rods to be equally divided into 30 pieces and connecting them in series.
If a common single power supply of about 140V is applied to the heaters 6 and 6, the amount of heat generated by the main heater section 5 will be about 40KW, and the amount of heat generated by the auxiliary heater section will be about 10KW.

As described above, the ratio of the calorific value of both heater parts 5 and 6 is suitably about 4:1 to 3:1.

The HIP device configured as described above performs heating with an electric heater in an inert high-pressure gas atmosphere and operates under pressure and temperature conditions of several hundred to 1,000 atmospheres and 500°C to 2000°C. When heat transfer is the main component, the workpiece present on the hearth 3 in the processing chamber 4 is surrounded by the main heater section 5, so the surface temperature in each part of the main heater section 5 is uniform. Since there is almost no difference in the amount of radiant heat between the top and bottom, excellent heat uniformity can be obtained.

In this case, since the radiant heat is not directly radiated from the auxiliary heater section 6 to the object to be processed, there is no adverse effect such as local heating, and therefore, heating operation can be performed while ensuring uniformity of temperature throughout.

On the other hand, when heat transfer is mainly due to low-temperature, high-pressure convection, the convection is extremely intense and a large amount of heat is carried upwards within the processing chamber 4, causing the temperature in the upper part of the processing chamber 4 to rise. As a result, the electrical resistance of the main heater section 5 increases, and as a result, the amount of heat generated by the auxiliary heater section 6 in a lower temperature range increases relatively, causing the temperature of the lower part to rise in a self-balancing manner. Heating operation is performed while maintaining uniform heat.

As described above, according to the present invention, when heat transfer is performed mainly by radiation, the radiation from the main heater part 5 arranged around the processing chamber 4 contributes to heating, and the auxiliary heater part in the lower part Since the radiation from the main heater section 5 hardly contributes to direct heat transfer, by keeping the temperature of each part of the main heater section 5 equal, it is possible to maintain the same temperature evenly in the upper and lower parts and obtain thermal uniformity. In addition, when heat transfer is performed mainly by convection, the temperature difference between the upper and lower parts can be eliminated by the heat generated by the auxiliary heater section 6, and it is possible to achieve the same heat uniformity performance. Thus, excellent heating operation can be performed under a wide range of temperature and pressure conditions.

Furthermore, the present invention has an auxiliary heater section 6 concentrically with respect to the main heater section 5. It has a simple structure of just installing it coaxially and connecting it in parallel, and it also has the economical advantage of keeping the equipment cost low because it has a single control and single power supply system as a whole. .

[Brief explanation of the drawing]

Fig. 1 is a schematic structural diagram of a HIP device according to one embodiment of the device of the present invention, Fig. 2 is a wiring diagram of the heating device in Fig. 1, and Figs. 3 and 4 are each embodiment of the device of the present invention. 1 is a schematic structural diagram of a HIP device according to the present invention. 4...Processing chamber, 5...Main heater section, 6...Auxiliary heater section.

Claims (1)

[Scope of utility model registration request] A heating device for heating the processing chamber 4 of the hot isostatic pressurizing device is equipped with an electric heater made of a material having a positive temperature coefficient of resistance, and power is supplied to the electric heater from a single power source. In addition, the electric heater includes a main heater section 5 mainly arranged around the processing chamber 4, and an auxiliary heater section arranged below the processing chamber 4 and having a higher resistance than the main heater section 5. 6 connected in parallel, a heating device in a hot isostatic pressurizing device.