JPS624872Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to improvements in a hot isostatic press (hereinafter abbreviated as HIP) device, and particularly to improvements in the arrangement and configuration of thermocouples in the heating device of the device.

Recently, HIP processing has attracted attention and is being put into practical use for purposes such as high-density sintering of metal or ceramic powder, removal of casting defects, and removal of residual pores in sintered parts. The equipment used is
It has the function of heating the processed product to 500 to 2000℃ in a high-pressure inert gas atmosphere of 1000 to 3000 atm and molding it into a specified shape by isotropic compression.It is usually placed in a high-pressure container whose outer surface is water-cooled. The reactor is equipped with a graphite heater or a resistance wire heating type heater, and a furnace structure consisting of a heat insulating structure that prevents the heat generated from the heater from being immediately transmitted to the high-pressure vessel. In this device, argon, helium, nitrogen, etc. are generally used as the inert gases used for pressurization, but these gases have high density and low viscosity under high pressure, so intense natural convection occurs. Therefore, in order to control this natural convection and equalize the temperature inside the processing chamber, the heater is usually divided into multiple zones in the vertical direction, so that the power input to each zone can be controlled independently. Designed.

FIGS. 1 and 2 show examples of such a HIP device, and in both examples, an upper lid 2 and a lower lid 3 are airtightly fitted to the upper and lower parts of a cylindrical high-pressure container 1 via seal rings 4 and 5, respectively. The workpiece support stand 3' of the lower cover 3
The object to be processed M is placed thereon, and an inert gas is introduced and discharged through the passage of the upper lid 2, and a heating element, that is, a heater element, is mounted in three or two stages 7a in an internal support cylinder 8. , 7b, 7c, and a heating device is basically installed inside the high-pressure container 1 and the upper lid 2 with a heat insulating structure 9 interposed therebetween. In this case, the temperature uniformity check,
That is, for temperature measurement, at least as many thermocouples 10 as the number of zones of the heater element are used,
These thermocouples 10 are connected to lead wires 11 and arranged in an annular space formed by the heating device and the object to be treated.

By the way, this annular space is small but sufficient compared to a furnace used under normal pressure or vacuum because it is relatively difficult for temperature distribution to occur in the horizontal direction due to the nature of the gas body, which is high temperature and high pressure. It has been found that, especially when designing with use under high pressures of 1,000 to 3,000 atm in mind, extra space leads to an increase in the size of the high-pressure container, so it is preferable from the viewpoint of safety and manufacturing cost. do not have.

However, with the arrangement of thermocouples as described above,
Since the annular space accommodates the thermocouple, there are constraints on its performance, and it does not necessarily meet the above requirements.

Therefore, consideration was given to reducing the installation space by grouping the thermocouples in each zone, but it is necessary to prevent short circuits between the wires of each thermocouple and ensure electrical insulation from the holding cylinder, etc. In order to obtain a satisfactory thermocouple arrangement and configuration, there are conditions such as the need to take into consideration the prevention of contamination by impurities in the atmosphere gas and components generated by volatilization from the object to be processed. I haven't reached it yet.

In view of the above circumstances, and in order to further solve the above problems, the present invention considers the appropriate arrangement and configuration of thermocouples, utilizes the gaps between adjacent heater element lead parts, and uses insulating tubes and protective tubes. The purpose of this invention is to provide a heating device that meets the above requirements by providing insulation and protection, and to provide an improved HIP device.

In other words, the feature of the present invention is that, in the heating device of a HIP device, a thermocouple is inserted into the gap between adjacent heater element lead parts pulled out downward, the thermocouple wire is passed through an insulating tube, and the entire The main feature is that it is housed and inserted into a protective tube.

Hereinafter, the present invention will be further explained in detail based on a specific example shown in the accompanying drawings.

Figure 3 shows an example of a heating device that includes a thermocouple arrangement according to the present invention, and shows a Fe-Al-Cr ₂ heating element used in a temperature range up to about 1250℃, and a heating device used in a temperature range below 1000℃. An overview of a heating device using a Ni-Cr heating element as a heater element is shown.

The structure of the furnace chamber containing the above-mentioned heating device is not particularly restricted, but basically the
Since it is illustrated in FIG. 2 and FIG. 2, it will be omitted here.

In FIG. 3, 7 is a heating element, that is, a heater element, as in FIG. 1 and FIG.
It is divided into two zones, each consisting of a longitudinally corrugated strip. Each of the heater elements 7a, 7b, 7c is suspended from a support cylinder 8 made of heat-resistant metal via an electrical insulator 12, and both ends of each heater element 7a, 7b, 7c are pulled out downward to generate heating power. Lead portions 7'a, 7'b, and 7'c for supply are formed.

In this configuration, the thermocouple 10, which forms the essential part of the present invention, is inserted and arranged in the space formed by the lead portions 7'a at both ends of the upper heater element 7a.

The thermocouple 10 is passed through an insulating tube 13 having two holes 14 in order to prevent a short circuit between the pair of two wires and to ensure electrical insulation with the supporting cylinder 8. 13 is fixed to the support cylinder 8 with a heat-resistant metal wire or the like. The material of the insulating tube 13 is usually alumina, beryllia, thoria, boron nitride, etc., and ceramic is preferable.

One or more pairs of thermocouples passed through the insulating tube 13 as described above are further housed in one protection tube 15 as shown in the figure.

This is to prevent contamination of the thermocouple by impurities in the inert atmosphere gas and components volatilized from the processed articles. The protection tube 15 is usually
Molybdenum, alumina, glassy carbon, boron nitride, graphite, etc. are used, but boron nitride is the most effective, considering that it can be machined to form threads and join in the longitudinal direction.
In particular, in the case of a protective tube made of ceramics such as alumina, which is susceptible to thermal shock and easily cracks, a molybdenum tube is placed on the inside or outside for double protection. Further, in order to prevent the above-mentioned contamination, it is preferable to use a protective tube whose upper end is sealed.

Of course, in order to perform accurate temperature control, it is preferable to use at least the same number of thermocouples 10 passed through the insulating tube 13 as the number of zones of the heater element, and usually two or more pairs of thermocouples are incorporated. In this case, one pair of thermocouples may be accommodated in one protection tube 15 as described above, or two or more pairs of thermocouples may be accommodated in one protection tube 15.

FIG. 4 shows another embodiment of the heating device including a thermocouple according to the present invention. The heating device shown in this figure is a graphite heating element that can be used even at high temperatures around 2000°C.

In this heating device, there are 2 heater elements.
The heater elements 7d, 7 have a zone configuration, and are formed into a longitudinal waveform by dividing a cylindrical graphite into two in the vertical axis direction and cutting vertical slits alternately from the upper and lower edges.
It is written as e.

Each of the heater elements 7d and 7e is provided with a protrusion 16 extending in the circumferential direction and having a width of an appropriate size in the thickness direction of the element at both end portions of the upper edge. A hole is drilled through it and is engaged at the hole by a graphite rod 17 and held in a suspended position. The graphite rod 17 is made of metal such as copper, molybdenum, graphite, etc., with fins 18 for shielding radiant heat and holes arranged alternately to suppress downward heat conduction as necessary, although it is not clear in the figure. Lead portions 7'd and 7'e are erected and fixed to a holding member made of a material, and are supplied with heating power.
Configure. In this case, heating power is independently supplied to each of the two divided heater elements.

Thus, in this embodiment, the thermocouple 10 is arranged in the gap between the lead portions 7'd at both ends of the upper heater element 7d. Particularly, as the thermocouple 10 capable of measuring high temperatures around 2000° C. as in this embodiment, an alloy of tungsten and rhenium with a different composition to form a positive wire and a negative wire is preferably used. Then, these thermocouple wires are connected to the insulating tube 1 in the same manner as shown in FIG.
3 and is housed in a protective tube 15 fixedly supported by a retaining ring 19.

The materials for the insulating tube 13 and the protective tube 15 are as described above, and ceramics such as boron nitride are most commonly used.

In particular, it is difficult to obtain long protection tubes, especially those made of graphite or ceramics, with large diameters, so it is better to accommodate two or more pairs of thermocouples in one protection tube to save space and cost. Preferable from the viewpoint of reduction.

The present invention has the above-mentioned configuration, and if such a heating device is placed in the furnace chamber defined by the cylindrical high-pressure container and the upper and lower lids, HIP processing can be performed in the same way as in the conventional method. , the processing object accommodation space is substantially
The thermocouple arrangement can be utilized, which is very effective in obtaining a large processing object storage space or achieving miniaturization of the apparatus.

As described above, the present invention is a heating device for a HIP device, in which a thermocouple is placed in the gap between the adjacent heater element leads pulled out downward, the wires of the thermocouple are passed through an insulating tube, and the entire body is housed in a protective tube. By placing the thermocouple in the gap between the heater element leads, it is possible to reduce the annular space conventionally provided for the thermocouple device. The internal volume of the high-pressure vessel can be made small relative to the furnace chamber dimensions. Therefore, the volume of the pressure medium gas in the high pressure container, ie, the energy of the gas pressure stored inside the pressure container, becomes smaller, making it possible to provide a safer HIP device. In addition, manufacturing costs are reduced as the dimensions of the high-pressure vessel are reduced in the production of the device, increasing practicality and improving economic efficiency during operation. It exhibits excellent performance such as shortening the time required.

In particular, in this invention, since the thermocouple wire is passed through the insulating tube, it is easy to arrange the thermocouple using the gap, and there is no risk of short circuit between the two wires, improving safety. In addition, the use of a protective tube has the advantage of preventing contamination of the thermocouple by impurities and components volatilized from processing objects, etc., and ensuring accurate temperature control.
The industrial and economic benefits of the HIP device as a temperature control device are enormous.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional schematic diagrams showing typical examples of HIP equipment including the arrangement of general thermocouple equipment;
The figure is a schematic perspective view of a heating device including the arrangement of thermocouples, which constitutes the essential part of the present invention, and Figures 4A, 4B, and 4 are schematic partial cross-sectional views of the front side showing other embodiments of the heating device of the present invention. FIG. 7a~7e...Heater element, 7'a~
7'e... Heater element lead section, 10...
Thermocouple, 13...Insulation tube, 15...Protection tube, 19
...Retaining ring.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A hot isostatic press device installed in the furnace chamber of a hot isostatic press device that pressurizes and heats a workpiece in a high-temperature, high-pressure gas atmosphere, in which a heater element lead portion is connected to an adjacent heater element lead portion. In the heating device that is pulled out downward with a gap between them, a thermocouple is inserted into the gap between the adjacent heater element leads, the thermocouple wire is passed through an insulating tube, and the entire body is housed in a protective tube. A hot isostatic press device characterized by being inserted. 2. The hot isostatic press apparatus according to claim 1, wherein one or more pairs of thermocouples are housed in the protective tube. 3. The hot isostatic press apparatus according to claim 1 or 2, wherein the upper end of the protective tube is sealed. 4. The hot isostatic press device according to claim 1, 2, or 3, wherein the protective tube is fixed to a holding cylinder or ring that fixes the heater element.