JPH0464015B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for measuring the temperature of an object to be processed in a hot isostatic pressing (hereinafter abbreviated as HIP) apparatus;
More specifically, the present invention relates to a method of measuring the temperature of an object to be processed in the above-mentioned apparatus using an optical fiber or the like. (Prior art) Currently, HIP equipment is equipped with temperature measurement means to detect the temperature inside the high-temperature and high-pressure furnace.
If the temperature inside the furnace exceeds ℃, W.5% Re− will be applied from the bottom of the furnace.
Measurement is performed by inserting a W.26%Re thermocouple into an insulating tube and then a protection tube, and fixing the hot junction at the height of the heater position in the furnace. However, with this measuring means, the thermocouple wire deteriorates significantly and reproducibility is poor, so the thermometer must be replaced after several charges, and the running cost is extremely high. Therefore, in order to eliminate such drawbacks, we have considered adopting high-temperature thermometers other than thermocouples, and have attempted to examine the suitability of each. That is, we will discuss gas thermometers, noise thermometers, fluid thermometers, and radiation thermometers as high-temperature thermometers other than the above-mentioned thermocouples, and examine the pressure resistance of the sensor bodies, changes in physical properties due to high temperature and high pressure atmospheres, and the characteristics of signal detection circuits. When we considered the difficulty level, we obtained the results shown in the following table, and found that the radiation thermometer was the best.

[Table] By the way, HIP conducted using a radiation thermometer
As for the temperature measurement inside the furnace, there is a report that the Battel Research Institute used a Saphire optical window to extract the light inside the furnace and perform radiation temperature measurement (DC Carmichael, PD
Ownby, ESHodge, “Hot Isostatic of
Graphite" BML-1746 (1965)). According to this, the window was damaged due to high temperature and high pressure, creating an extremely dangerous situation, so temperature measurements were not carried out continuously. Because heat radiation is guided out of the pressure vessel through the optical window attached to the pressure vessel components, the optical window is overheated by the transmitted radiation heat, which reduces the strength of the window and prevents it from breaking when high pressure is applied. This is because the installation of the above-mentioned optical window requires opening a hole in the pressure vessel, but such a hole naturally
This results in a decrease in the pressure resistance of the pressure vessel. In particular, in the case of a HIP device, since high-pressure gas is sealed inside the pressure vessel, damage to the optical window or the pressure vessel may cause a major accident and is a safety issue. On the other hand, existing radiation thermometers that use optical fibers as waveguides use bundled fibers to increase the amount of light in order to expand the temperature measurement range, so if they are inserted into a high-pressure container, there is a problem with the pressure seal. There is. Furthermore, it is difficult to use it in an atmosphere of 100° C. or higher without water cooling, and it cannot be said to be practical. Furthermore, as a general thermometer using optical fiber, a standard temperature emitting object attached to the input end of the optical fiber has been proposed in JP-A-56-129827, but this is because the optical fiber is Since the standard temperature radiating object is attached to the input end as described above, there is a drawback that when the temperature radiating object becomes high temperature, the optical fiber melts or devitrifies, making temperature measurement impossible. In other words, this method is intended to indirectly measure the temperature of a temperature-measuring object by increasing the temperature of the temperature-emitting object through heat radiation from the temperature-measuring object, and to measure the temperature of a high-temperature atmosphere. That is virtually impossible. However, in HIP equipment, maintaining the inside of the furnace under the required high-temperature atmosphere is an extremely important issue in terms of processing, and an appropriate temperature measurement method for this is a current issue that is equally desirable as the HIP equipment is put into practical use. It is. (Object of the invention) The present invention addresses the above-mentioned actual situation and problems, and
Our goal is to provide a temperature measurement method suitable for detecting the temperature of a processed object in a HIP device, and we focus on the use of optical fibers, particularly using metal-coated fibers, fiber bundles, or rod-shaped optical materials with the same effect. Using a radiation thermometer, guide the metal-coated optical fibers through a hole in the sample stage in a high-temperature, high-pressure furnace.
The object is to directly receive thermal radiation power from an object to be measured, take it out of the furnace, and perform radiation temperature measurement without requiring a temperature measuring element inside the furnace. (Structure of the Invention) The present invention, which achieves the above object, is characterized by the use of metal-coated optical fibers, optical fiber bundles, or equivalent rod-shaped optical materials (hereinafter referred to as optical fibers, etc.). The tip is inserted into the high-pressure furnace of the HIP device so as to receive the heat radiation inside the furnace, and the light is guided out of the container through the high-pressure container lid, and a hole is opened in the sample stage on which the object to be processed is placed. The measurement system connected to the optical fiber detects the heat radiation power from the temperature-measuring object transmitted by the optical fiber, etc. by observing the bottom part from the tip of the optical fiber, and It's in the method of measuring temperature. Here, the means for coating the optical fiber or the like with metal may be either a metal coat or a metal sheath. The metals used for metal coating are:
Examples include Al, Cu, Co, Ni, MoW, Pd, Pt, etc., which are stable alloys with Si in optical fibers made of _SiO2 .
Aluminum (Al) is the most common. The metals used for the metal sheath are Fe, Ti, Cu,
Zn, Pb, Sn, Al, Cr, Co, Ni, Mo, W, Pd,
All metals such as Pt can be used. In addition to quartz or sapphire, the rod-shaped optical materials include materials having the same effective thermal radiation power transmission ability as optical fibers, and these rod-shaped optical materials are also coated with the metal. Next, the optical fiber, etc. must be inserted so that at least its tip is present in the high-pressure container of the HIP device, and in that case, the position of the tip is basically a heater, Since a heat insulating layer and a sample stand on which the object to be processed is placed are provided, these are used as the object to be measured, so depending on the selection of each object to be measured, the temperature at the tip, that is, the thermal radiation power ( Set the incident end of radiant energy). Although the optical fibers and the like may be taken out of the furnace through the upper lid of the high-pressure container, they are usually taken out through the lower lid and connected to a radiation thermometer provided outside. In this case, a seal is required between the high-pressure vessel and the optical fiber, etc., but since the optical fiber is coated with metal, it is possible to braze or weld directly to the flange, etc., making it possible to seal the high-pressure can be carried out easily and reliably. Note that even if it is necessary to use fibers in a bundle due to insufficient light intensity or insufficient strength of the fibers, high-pressure sealing is possible by combining metal-coated fibers with brazing or welding techniques. (Actions and Effects of the Present Invention) As described above, the present invention provides HIP for the tip of an optical fiber, etc.
This is a method in which the temperature inside the furnace is detected by inserting it into the device, transmitting the thermal radiation power from the object to be measured, and taking it out of the furnace. The principle of detecting the temperature of an object is already known as described in Japanese Patent Laid-Open No. 129827/1983. The present invention uses a temperature detection method based on such a known principle to directly measure the temperature of an object to be processed, particularly in a closed high-pressure container called a HIP device. It becomes possible to directly measure the temperature of the object to be processed using an optical method. In other words, the heat radiation from the inside of the HIP device's furnace is led out of the furnace through a metal-coated optical fiber or optical fiber bundle, or an equivalent rod-shaped optical material, which is much safer than an optical window. It becomes something. Since the optical fiber or the like is coated with metal, high-pressure sealing can be performed easily and reliably. In other words, this coating metal can be brazed and/or welded to the lid or a member to be attached to the lid. With this configuration and by drilling a hole through the sample stage on which the object to be processed is placed, this hole also functions as a black body, allowing for accurate temperature measurement of the object to be processed. The temperature of the processing body can be controlled with high precision. In this way, compared to temperature measurement using conventional thermocouples, there is no need for a temperature measurement element inside the furnace, so it is possible to measure temperature stably for a long period of time, and the temperature can be easily measured even at the temperature measurement upper limit of thermocouples. Moreover, since it does not require anything like an optical window, there are no safety problems, and it is extremely effective as a temperature measurement means for HIP equipment that has high-pressure gas sealed inside. (Aspects of Implementation) Hereinafter, each aspect for implementing the method of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 shows the basic configuration of a HIP device to which the method of the present invention is applied. It is constructed by arranging the layer 4 and the heater 5 to form a furnace, and installing a sample stage 6 on which the object to be processed is placed on the lower lid 3. Figure 2 shows the temperature measurement of the optical fiber, etc., when the heat radiation of the object to be processed M in the furnace is guided to the outside using an optical fiber, etc., and the radiation power is detected to measure the radiation temperature in the HIP device as described above. An example of the arrangement of optical fibers, etc. corresponding to the target is shown.
An optical fiber or the like 7 is embedded therein so that the bottom of the object to be processed M is used as a temperature measurement target. This has the advantage that the temperature of the object M to be processed can be directly measured, and is extremely effective. Further, the optical fiber etc. 7 shown in the above example can be used with collimators 8a to 8a as shown in FIGS.
By attaching 8d, stray light incident from sources other than the temperature measurement target can be removed, and only heat radiation from the target object, that is, the object to be temperature measured, can be reliably extracted, and the temperature of the target object can be measured with higher accuracy. Incidentally, the arrangement shown in FIG. 3B can prevent dust from accumulating on the collimator 8b and reducing the amount of light incident on the optical fiber or the like 7. Furthermore, the collimator 8c in FIG.
In this example, a cavity is formed by making the diaphragm 10 into two stages, and the amount of stray light is reduced compared to other types. Next, FIG. 4 is an example of taking out the optical fiber etc. 7 out of the furnace, and the illustration of the optical fiber etc. 7 passing through the hole in the sample stage 6 is omitted, but the lower cover 3 of the HIP device
The radiation thermometer 11 is taken out to the outside and connected to a measurement system consisting of a radiation thermometer 11. In this case, if the lower lid 3 is composed of both an upper lid and a lower lower lid as shown in the figure, it is necessary to seal between the two with an O-ring 12 or the like.
In addition, the high pressure container and the optical fiber 7 also need to be sealed. 7A, 7B, and 7C show various forms of sealing between such a high-pressure container and an optical fiber, etc., and since the optical fiber 7 is coated with a metal coating 13 on its outer surface, this metal coating Using 13, a metal plate 14 is brought into contact with the outer surface of the high-pressure cylinder 1 wall, and brazing or welding 15 is performed between the two, and if the metal plate is thick, a bolt 16 and a nut 17 are also used in addition. Seal. Also, as shown in FIG.
It may be used in combination with 5. The above-mentioned sealing means are similarly applicable to both the case where the optical fiber is a focused fiber bundle and the case where the optical fiber is a rod-shaped optical material. In this way, the optical fiber etc. 7 is taken out of the furnace,
It is connected to a radiation thermometer 11 to detect and measure the temperature. FIG. 5 is a block diagram of such a radiation thermometer 11. In order to increase the light receiving sensitivity of the photoelectric conversion element, the signal light is chopped and the timing is clarified. In order to do this, a reference electrical signal is sent from the chopper to a lock-in amplifier, where it is processed in accordance with the electrical and electronic processing circuit shown in FIG. 6 and displayed as temperature. Of course, the radiation thermometer light temperature conversion section is a normal radiation thermometer, and a Si photodiode or the like is used as the photoelectric conversion element, but its configuration is not particularly intended by the present invention, so details thereof will be omitted. (Another Embodiment) Each aspect regarding the arrangement and installation of the optical fiber etc. in the method of the present invention is as described above, but in the above explanation, the optical fiber etc. has been explained as a single member. However, optical fibers etc. do not necessarily have 1
It is not necessary to set multiple objects to be measured at different locations in the furnace, and use multiple optical fibers at the same time to target them. In this case, the temperature measurement of each optical fiber, etc. Out of the furnace location to the target,
By changing the height, it becomes possible to detect the distribution situation in the vertical direction all at once. In addition, when using optical fibers as a bundle, it is also possible to spread out the incident part at the tip in an octopus shape to transmit the thermal radiation power of each target and measure the temperature. Furthermore, in each of the above embodiments, the optical fibers and the like are led out of the furnace through the lower lid, but it goes without saying that the same can be done through the upper lid. Furthermore, it goes without saying that the present invention can also be applied to a pressure sintering furnace having the same function as a HIP device.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing the basic configuration of the HIP device, Fig. 2 is a sectional view of main parts showing an example of the arrangement of optical fibers, etc. in the present invention, and Fig. 3 A to D are optical fibers with various collimators attached. FIG. 4 is a schematic cross-sectional view of the main part showing how the optical fiber is taken out of the furnace. FIGS. 5 and 6 are a radiation thermometer used in the present invention and its lock-in. Each block diagram of the amplifier and FIGS. 7A to 7C are schematic cross-sectional views showing the sealing structure of optical fibers and the like. DESCRIPTION OF SYMBOLS 1...High pressure cylinder, 2...Upper lid, 3...Lower cover, 4...Insulating layer, 5...Heater, 6...Sample stand, 7...Optical fiber etc., 8a-8d...Collimator, 11... ...radiation thermometer, 13...metal coating.

Claims (1)

[Claims] 1. Insert a metal-coated optical fiber or optical fiber bundle or a rod-shaped optical material with the same effect into a high-pressure furnace of a hot isostatic pressurization device so that its tip entrance part can receive the heat radiation inside the furnace, The output side of the rear end is guided to the outside of the high-pressure container through the lid of the high-pressure container, and the lid of the high-pressure container made of a metal material or the attachment member to the lid and the optical fiber coated with the metal are fixed by brazing and/or Or by welding, in the temperature measurement system of a hot isostatic pressurization device with a measurement system connected to the output end, the temperature of the object to be processed is measured through a hole opened in the sample stage on which the object to be processed is placed. A method for measuring the temperature of an object to be processed in a hot isostatic pressurizing apparatus, characterized in that the temperature measurement method is carried out by observing the bottom of the object from the tip entrance section.