JPH0334640Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a hot isostatic pressurization device, which uses an inert gas of several hundred to several thousand atmospheres as a pressure medium, and simultaneously heats the temperature from several hundred degrees to 2000 degrees. It is used to generate high temperatures of 0.degree. C. or higher to sinter powder materials to high density, to improve local defects in cast products by crushing them, and to diffusion bond various materials.

(Conventional technology) Hot isostatic pressurization equipment (hereinafter referred to as HIP) is
Temperature control inside the furnace is important, and for this reason,
There is a technique disclosed in Japanese Utility Model Publication No. 58-13277.

This conventional technology installs a thermocouple to increase the temperature inside the furnace, which creates the Seebetzk effect.
The electromotive force generated at this time is taken out to the outside through a lead wire and converted into temperature. Examples of thermocouple wires include platinum-rhodium and tungsten-rhenium.

There is also a thermocouple housed in a capped cylindrical protective tube made of graphite, ceramic, or the like.

(Problems to be Solved by the Invention) In the above-mentioned conventional technology, if the HIP treatment is performed continuously or repeatedly, the temperature error becomes large.

This is because the physical quantity called electromotive force is easily influenced by the environment.

Therefore, in the high temperature and high pressure treatment of 2000° C. and 1000 atm or more in HIP, the life of the thermocouple is significantly shorter than that at low temperature and low pressure, which also poses a cost problem.

For example, under conditions of 2000°C and 1000 atm, deterioration of about 1% (20°C) occurs in about 1 hour.

This invention replaces the conventional method of measuring temperature inside a furnace based on electromotive force, and uses the thermal expansion of substances to measure the coefficient of linear expansion of the material, thereby determining the relationship between temperature and coefficient of linear expansion. In addition to knowing the temperature,
Due to the nature of HIP equipment, the temperature distribution inside the furnace tends to vary depending on the pressure, and in particular, the temperature gradient in the lower part of the furnace chamber varies greatly depending on the pressure, so we designed it to be able to compensate for the effect of the temperature gradient in that part. With the goal.

(Means for Solving the Problems) The present invention has a high pressure chamber 4 defined by a high pressure cylinder 1 and an upper cover 2 and a lower cover 3 that seal the upper and lower openings thereof. It has a furnace chamber 9 surrounded by a capped cylindrical heat insulating layer 6 and a heating element 8 arranged concentrically therein, and is equipped with a thermometer for measuring the temperature of the furnace chamber 9. The above object has been achieved in the hot isostatic pressurizing device by taking the following technical measures.

That is, in the present invention, a heat-resistant and linearly expandable temperature measuring rod 12 is placed at a radially corresponding position within the furnace chamber 9 and at approximately the same radial position as the heating element 8. It is provided along the height direction,
Sensor 1 that measures expansion and contraction due to linear expansion of temperature measuring rod 12
8 are provided at the same height position, and each of the sensors 18 is provided with a temperature measuring rod 12 having a different length.

(Function) During the HIP process, the temperature measuring rod 12 expands and contracts due to linear expansion depending on the temperature of the furnace chamber 9.

Due to this expansion and contraction, the electromagnetic induction sensor 18
At this time, the magnetic field changes and an induced electromotive force is generated. This electromotive force is transmitted to the outside of the furnace via lead wires and converted into temperature.

Further, when the sensor 18 uses the strain gauge 22, the amount of strain is transmitted to the outside of the furnace and converted into temperature.

Correction of the temperature measurement error due to the influence of the temperature gradient section in the lower part of the furnace chamber 9 becomes possible by measuring each of the plurality of temperature measurement rods 12 with the sensor 18.

That is, as shown in FIG. 9, the temperature of the A section can be measured by measuring the relative lengths of the sensor 18 at the X section and the sensor 18 at the Y section, and the temperature of the A section can be measured by measuring the relative lengths of the sensor 18 at the Y section and the sensor 18 at the Z section. It becomes possible to measure the temperature of part B by measuring the relative length of.

Therefore, it is possible to correct the influence of the temperature distribution below section A (and/or the influence of the temperature distribution below section B), making it possible to accurately measure temperature.

Furthermore, when using at almost the same pressure all the time, the temperature gradient at the bottom will always be the same if the temperature of the temperature measuring part is the same, so by calibrating with other methods such as thermocouples, The top is fully usable.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In FIG. 1, 1 is a high-pressure cylinder, which is a cylindrical body having upper and lower openings.

2 is an upper lid, and 3 is a lower lid, which seals the upper and lower openings of the high-pressure cylinder 1, and has a high-pressure chamber 4 defined by the high-pressure cylinder 1, the upper lid 2, and the lower lid 3. .

Note that the upper lid 2 and the lower lid 3 can be inserted and removed freely, and the press axial force can be supported by engaging the press frame 5. be.

Reference numeral 6 denotes a heat insulating layer, which has a capped cylindrical shape with a sealed upper part, is supported by a hanger 7 on the upper lid 2, and is arranged concentrically within the high pressure chamber 4.

A heating element 8 is arranged concentrically inside the heat insulating layer 6, and has a furnace chamber 9 surrounded by the heating element 8 and the heat insulating layer 6, and a hearth in the lower part of the furnace chamber 9. 10, this hearth 10 is a sample stand, and in this embodiment, the object to be processed 11 can be freely inserted and removed from the lower part.

Note that the heating element 8 may be provided in multiple stages.

Reference numeral 12 denotes a temperature measuring rod, and as shown in FIG. 2, it is arranged concentrically with the heating element 8 (approximately the same position in the radial direction) at a radially corresponding position in the furnace chamber 9, and the rod's longitudinal direction is radially corresponding to the heating element 8. 9 along the height direction.

The temperature measuring rod 12 is made of a heat-resistant and linearly expandable material such as tungsten or ceramics, and is supported by the structure shown in FIGS. 3 and 4.

That is, as shown in FIG. 3, a female thread 14A is formed on the top of a crested cylindrical protection tube 14 which is detachably attached to the sample stage 10 with a screw 13 as shown in FIG. It is attached by screwing in the top male thread 15 of the rod 12 or by a pin 16 as shown in FIG.

The protective tube 14 may be made of graphite, graphite, or the like, and may be attached to the sample stage 10 using screws 17 as shown in FIG.

Further, the pin 16 is made of tungsten, ceramics, or the like.

18 is a sensor, and in the embodiment shown in FIGS. 5 and 6, a coil 20 is wound around a cylindrical magnet 19. The magnet 19 is attached to the sample stage 10 with a support (not shown), and a , as shown in FIG. 7, is constructed by inserting the lower end of the temperature measuring rod 12.

Therefore, in the embodiments shown in FIGS. 5 and 6, HIP
Due to temperature changes in the furnace chamber 9 during processing, the temperature measuring rod 12 expands and contracts linearly, and this expansion and contraction changes the magnetic field, generating an induced electromotive force, which is transmitted to the outside of the furnace through lead wires, etc. , which will be converted into temperature.

Furthermore, as shown in FIG. 8, the sensor 18 may be such that a strain gauge 22 is attached to a metal plate 21 and the expansion and contraction of the temperature measuring rod 12 on the metal plate 21 is read as strain.

That is, the sensor 18 may be a sensor using electromagnetic induction as shown in FIGS. 5 to 7, or a strain gauge as shown in FIG.

Furthermore, the measurement by the sensor 18 can be taken out of the furnace through the lower lid 3 using a lead wire or the like.

Figure 9 shows a sensor 18 that can correct temperature measurement errors due to the influence of the temperature gradient section at the bottom.
The positions of are the same, and the length of the temperature measuring rod 12 is marked A,
By measuring the relative length A between the X and Y positions of the sensor 18 and the relative length B between the Y and Z positions of the sensor 18, the error can be eliminated. It can be corrected.

In other words, due to the nature of HIP equipment, pressure tends to cause differences in temperature distribution within the furnace. In particular, the temperature distribution in the lower part of the furnace chamber varies greatly depending on the pressure. In the case of the thermometer using linear expansion of the present invention, this difference in temperature distribution in the lower part of the furnace chamber has a large effect on the accuracy of temperature measurement. That is, the elongation of the temperature measuring rod 12 differs depending on the temperature gradient in the lower part of the furnace chamber. In order to compensate for the influence of the temperature gradient in the lower part of the furnace chamber, the sensors 18 are installed at the same height as shown in FIG. When installed individually like this, sensors X,
Sensor Y makes it possible to measure the temperature at the relative height (length) A, and sensors Y and Z make it possible to measure the temperature at the relative height (length) B. Become. Therefore, it is possible to correct the influence of the temperature distribution below section A (and/or the influence of the temperature distribution below section B), making it possible to accurately measure temperature.

In addition, as shown in FIG. 1, it is equipped with means for supplying and discharging a pressure medium (inert gas such as argon), etc.

Furthermore, necessary components for HIP such as a power supply circuit for the heating element are naturally provided, and the detection by the sensor 18 is communicated to the calculation section (measurement control section) etc. through an amplifier or the like.

(Effects of the invention) According to the invention, when measuring the temperature inside the furnace (room), a temperature measuring stick is not used, unlike the conventional example, in which the physical quantity of electromotive force caused by a thermocouple is easily influenced by the environment. The relationship (proportional relationship) between temperature and linear expansion coefficient can be determined by measuring the linear expansion coefficient of the material using the thermal expansion of It also enables stable temperature measurement and has good reproducibility, so it can have a long service life.

In addition, since the temperature measuring rod is placed radially at the same position as the heating element (on a concentric circle), the space required for temperature measurement can be reduced, resulting in more efficient use of the volume of the furnace chamber. becomes.

Furthermore, due to the nature of HIP equipment, pressure tends to cause differences in temperature distribution within the furnace. In particular, the temperature distribution in the lower part of the furnace chamber varies greatly depending on the pressure. In the case of the thermometer using linear expansion of the present invention, this difference in temperature distribution in the lower part of the furnace chamber has a large effect on the accuracy of temperature measurement. That is, the elongation of the temperature measuring rod 12 differs depending on the temperature gradient in the lower part of the furnace chamber. In order to compensate for the influence of the temperature gradient in the lower part of the furnace chamber, in the present invention, the sensor 18 is installed at the same height, and the temperature measuring rods 12 of different lengths are placed separately as shown by the symbols A and B. By installing sensors
It becomes possible to measure the temperature at a portion of relative height (length) A, and it becomes possible to measure the temperature at a portion of relative height (length) B using sensors Y and Z. . Therefore, since it is not possible to correct the influence of the temperature distribution below part A (and/or the influence of temperature distribution below part B), it is possible to accurately measure temperature.

Therefore, since the problems specific to HIP devices can be solved, the present invention has unique significance, unlike ordinary temperature measuring devices that utilize linear expansion.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a vertical sectional elevation view, FIG. 2 is an enlarged cross-sectional view taken along lines from FIG.
Figures 5 and 4 are cross-sectional views showing two examples of temperature measuring rod attachment (support part), Figures 5 and 6 are cross-sectional views showing two examples of the sensor part, Figure 7 is a perspective view of the sensor, 8
The figure is an elevational view showing another example of the sensor, and FIG. 9 is an explanatory diagram showing an example of the arrangement of temperature measuring rods. DESCRIPTION OF SYMBOLS 1... High pressure cylinder, 2... Upper cover, 3... Lower cover, 4... High pressure chamber, 6... Heat insulation layer, 8... Heating element, 9... Furnace chamber, 12... Temperature measuring rod, 18... …sensor.

Claims (1)

[Claims for Utility Model Registration] A high-pressure chamber 4 defined by a high-pressure cylinder 1 and an upper cover 2 and a lower cover 3 that seal the upper and lower openings of the cylinder has a crested cylindrical shape whose upper part is sealed. A hot isostatic press having a furnace chamber 9 surrounded by a heat insulating layer 6 and a heating element 8 arranged concentrically therein, and equipped with a thermometer for measuring the temperature of the furnace chamber 9. In the pressure device, a heat-resistant and linearly expandable temperature measuring rod 12 is installed at a radially corresponding position in the furnace chamber 9 and at approximately the same position in the radial direction as the heating element 8 . A plurality of sensors 18 are provided along the longitudinal direction and measure the expansion and contraction due to linear expansion of the temperature measuring rod 12. A plurality of sensors 18 are provided at the same height position, and temperature measuring rods 12 of different lengths are attached to each of the sensors 18. A hot isostatic pressurizing device characterized in that it is separately provided.