JPS60142222A - Method for measuring temperature distribution in furnace in hot hydrostatic pressing apparatus - Google Patents

Abstract

PURPOSE:To measure a temp. distribution in a furnace precisely and stably for a long term by setting plural tubes, which are different in length and closed at the ends, to a high pressure furnace, detecting a thermal emission from an inner wall of said tubes at the opening hole parts thereof to perform arithmetic processing. CONSTITUTION:The tubes 12 whose ends are closed are set while penetrating a furnace wall 11 of a high-pressure vessel. Detectors 13 containing photoelectric converters are provided at the opening hole parts of said tubes to convert the thermal emissions from the top end parts of the tubes 12 to electric signals to amplify them by amplifiers 14, then said signals are introduced to a computer 15 to perform respective necessary arithmetic processings. Thereat, the temp. measurement error due to stray light from side walls of the end closed tubes is corrected to take out only the thermal emission power at the top end part of said tube and to measure the temp. distribution in furnace. Thereby, the temp. distribution in furnace can be measured precisely and stably for a long term.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for measuring temperature distribution in a furnace of a hot isostatic pressing (hereinafter abbreviated as HIP) device, particularly a closed This relates to the standard method for temperature distribution in the furnace of the device 31 described below, which utilizes optical fibers arranged in end tubes.

(Prior art) Currently, when measuring temperature distribution in a furnace, HIP equipment requires
The commonly used method is to install multiple thermocouples in different locations, but there are problems such as deterioration of the thermocouple wires due to the high temperature atmosphere of 1'600 to 2000 degrees Celsius, and temperature measurement errors due to shunt errors. .

On the other hand, as a new temperature distribution measurement method, there is an ultrasonic temperature measurement method that uses ultrasonic waves, which has the advantage of being able to measure one-dimensional temperature distribution with one sensor body. When installed in a high-temperature atmosphere inside a building, it has the disadvantage of poor durability and reliability.

However, under these current circumstances, the only device that can accurately measure the temperature distribution in the furnace of the H-P equipment over a long period of time is the H-P equipment.
This is a very important opening from the perspective of practical use of IP devices, and a means of measuring it is strongly desired.

Therefore, in order to respond to requests from both parties, we have developed various high-temperature and humidity devices other than thermocouples, such as gas thermometers, noise thermometers, fluid thermometers, and radiation thermometers. The suitability of its use was considered with regard to changes in the signal detection circuit and the degree of difficulty of the signal detection circuit. As a result, it was found that the radiation temperature method using an optical fiber is the most suitable and excellent method.

This method is disclosed, for example, in Japanese Unexamined Patent Publication No. 56-29827, and is a method in which radiation temperature is measured by guiding thermal radiation from a temperature-emitting object through an optical fiber.
Recently, its use has been attracting attention, but this method also has the disadvantage that if the optical fiber is placed under a high-temperature furnace inside the furnace, the optical fiber will be heated and melted by heat conduction and convection inside the furnace. It has been found that there is a fear that this may occur, and that it is still not perfect.

Therefore, the present inventors continued to study, combined the optical fiber with a closed-end tube, installed the closed-end tube in a HIP furnace, attached the optical fiber to the open end of the closed-end tube, and attached the optical fiber to the open end of the closed-end tube. We discovered a temperature measurement method in which the heat radiation from the furnace is transferred to the outside of the furnace through an 11iJ optical fiber and separately proposed.

(Objective of the Invention) The present invention is directed to a one-item tube using the closed-end tube according to the proposal.
We further developed the filling method by fixing a plurality of closed-end tubes of different lengths in a furnace, detecting heat radiation from the inner wall, and
By performing positive calculations, the temperature distribution in each heating zone in the furnace can be accurately and stably maintained over a long period of time.
The purpose is to determine l+.

(Structure of the Invention) Therefore, the measuring method of the present invention that achieves the above object is
In a HIF device in which a heat insulating layer and a heating device are arranged in an E-container to form a high-pressure furnace, the high-pressure ,
The tip is positioned and inserted in each heating zone so that heat radiation corresponding to each heating zone is radiated into the inside of the closed-end tube,
The input end of the optical fiber is inserted into the 1-1 section between each closed-end tube, so that it can receive the internally emitted light at the end of the closed-end tube, and the output end of the optical fiber is taken out of the high-temperature container and connected to the measurement system. Connect to detect the thermal radiation power from the inner wall of each closed X1li tube,
Then, correction calculation processing by subtraction is performed to derive only the temperature due to the thermal radiation power from the tip of each closed-end tube in each heating zone in the furnace, and the temperature distribution in each heating zone is measured.

Here, the closed-end tube is usually made of a heat-resistant material such as tungsten, molybdenum, boronite, or graphite. When the optical fiber can be removed, the opening is held using a holding jig, etc.; Since the viewing angle (viewing angle) is approximately 24 degrees, the optical fiber receives not only thermal radiation from the closed-end tube tip but also thermal radiation from the closed-end tube side wall.

Of course, it is conceivable to provide a collimator, lens, etc. close to the end of the closed-end tube in order to prevent thermal radiation from the side wall of the closed-end tube from entering the optical fiber, but in the present invention, this will be described later. By eliminating the temperature measurement error through correction, a field-of-view limiting means such as a collimator or a lens is not used at the tip of the optical fiber, and the optical fiber is used as it is as polished.

By the way, in the measurement method of the present invention, it is important to extract the thermal radiation power from the tip of the closed-end tube and to know the temperature based on this. This will result in an error.

Therefore, in the case where only the tip is heated by the heating device, that is, if there are N closed-end tubes or closed-end tubes for the lower heating zone, the temperature of each tip is Tl + T2 · from the shorter one. ...Assuming TN-i + TN, 'r1<'r+t<...<TIJ-1
In the case of the relationship <jlJ, the temperature of the side wall is sufficiently lower than the temperature of the tip, so by shortening the detection wavelength of the radiation temperature d1 to 5 degrees so that the heat radiation from the side wall can be ignored, the heat from the tip can be reduced. Extracting only the radiation provides nJ capability, allowing accurate temperature measurement.

However, when a closed-end pipe is divided into two or more heating zones and has a corresponding length, the middle or upper heating zone is heated by the lower or middle heating zone, so the side wall The temperature may be higher than the tip temperature. In that case, the temperature of the side wall with the highest humidity, instead of the tip, is determined to be f:1 Instead, specify a value close to T.

Therefore, it is necessary to correct this error, but in order to perform such correction, it is necessary to subtract the thermal radiation incident on the optical fiber from the side wall from the total thermal radiation incident on the optical fiber, and Mfj' ( Subtract the output due to thermal radiation from the side wall at a temperature of '1' from the output of the detector corresponding to 2. However, in this case, assume that the tip temperature of the shortest closed-end tube is higher than the side wall temperature. However, it is assumed that the true value of T is superior.

And, when T2 lives in this way, next time I”
, , T2 is used to correct the output of the next detector to obtain '1゛3, and by repeating this operation, from the temperature T at the tip of the shortest closed-end tube to the humidity TN at the tip of the longest closed-end tube, can be measured with high precision.

To help understand the above method, the following will be explained with reference to drawings. In Fig. 1, in the closed-end tube (Hl) with the shortest length, Since the thermal radiation power (Wl) incident on the optical fiber is only the thermal radiation from the tip, W+-fIR(TI)...
1) holds true. Here, fl is the view factor when looking at the tip of the shortest closed-end tube (Hl) from the input end face of the optical fiber, and R(TI) is the thermal radiation power from an object at temperature T1.

Therefore, using equation (1), since w1+fI is known, R(T,) can be calculated.

Next, to calculate the temperature T1 from R(T,), use the following relational expression (2).

f11shi1. l, , z2 are the upper and lower limits of the detection wavelength.

λ is the wavelength of heat radiation.

0,. 02 is the blank 1st. Second radiation constant.

However, this formula (2) cannot be immediately reduced to 11γr with respect to T, but by making a numerical table of the relationship between R(T,) and T1, R(T,)
However, it is easy to claim blackness T.

In this way, in the case of the closed-end tube (H3), the tip temperature (T,) can be determined with high accuracy only from the data of the thermal radiation power (W,) incident on the optical fiber.

Note that the view factor f is 31 m from the length and inner diameter of the closed-end tube (Hl) and the core diameter of the optical fiber.

However, in general, this view factor is expressed as fi, which is determined by the following formula depending on the shape of the tip of the closed-end tube. (f) If the tip is flat, (see Figure 2 (a))
However, L: Length of the cylindrical part of the closed-end tube 2r; Inner diameter of the closed-end tube 2a; Core diameter of the optical fiber (same below) (0) If the tip is spherical, (see Figure 2 (b))
×Cσノφdφ (c) If the tip is conical (see Figure 2 (c)) -
, (X2-4-2L7.X-rt) ta fear, (/l
= 'l' □ The tip temperature (T2
) is measured using the power (W2) incident on the optical fiber from the closed end q=' (H2).

In this case, if the (Ll) part of the closed-end tube (H2) is at the temperature T1, then there is w2-T
2 R(”2) + 9HR(TI) ・・・・・・−(
3) thermal radiation power is incident. However, f2+′! Is l the above closed end from the input end face of the fiber? The shape of the tip of J (H2) and the side wall of the (L2 Ll) part is determined by the number of threads, the length of the closed-end tube (H2), the inner diameter, and the core diameter of the optical fiber, and the second (see figure).

Equation (3) for the manure is determined by knowing W2 + T2 + 'l, and according to the above description, R from the shortest closed-end pipe (Hl).
Since (TI) is known, R(T2) can be determined, and the tip temperature (T2) can be calculated similarly to equation (2).

Furthermore, considering the method of measuring using the power (W3) incident on the optical fiber from the closed-end tube (H3), the tip temperature (T3i) of the closed-end tube (H3) with the third length L3), in this case , (L3 [12) part temperature (T2)
, (L12"+) is at temperature (T1), the optical fiber has the following properties: W3-fa R(T3) 4-92 R(T2)+7°R(T1)... ...The power of (4) is incident. However, T3 + T2 is the view factor when looking at the tip of the third closed-end tube (H3) and the side wall of the portion (L3-L2) from the optical fiber input end surface. This is a constant determined by the length and inner diameter of the closed-end tube (L, ) and the core diameter of the optical fiber.

However, in equation (4), W3 + T3 + li'□
, ri, is known, and the closed i7W /i'l',' (H
By knowing R(TI) and R(T2) from +1 and (H2), R(T, ) can be determined, and from there, the temperature ('r3) can be determined in the same way.

Below 1-. By performing radiation temperature measurement in consideration of heat radiation from the side walls, the temperature of the upper, middle, and lower three zones (
'T+)(']12)(13) can be measured with high accuracy.

Note that when formulas (1), (3), and (4) above are written using matrices, the above is for three zones, but when there are four or more heating zones, or more precisely, In other words, when increasing the number of closed-end tubes for temperature measurement and measuring the temperature at position n using nine closed-end tubes of different lengths, the above formula (5) can be generalized. The equation is 0, and after all, the temperature at position n can be measured from this equation.

The correction method explained above is shown in FIG.
The temperature of the (L2 Ll) part is TI + (L
The temperature at the part 3 L2) was corrected by assuming that the temperature at the side wall of the closed-end tube was step-like, such as T2, but in reality, this assumption does not necessarily match. Furthermore, we consider correction methods based on assumptions that are closer to reality.

This assumption, shown in FIG. 31(b), assumes that the temperature of the side wall portion of (L2 Ll) increases linearly from '1'2 to T3.

Based on this assumption, the amount of thermal radiation incident on the fiber from the (L2 TJI) portion can be expressed as 7. of equation (3) above. R
In place of (1', ), we introduce a function G1 (1'l, ']'2) that takes into account the temperature gradient between (L2 +,).

2r; inner diameter 2a of closed gjM tube; core diameter λ of SOC fiber; wavelength λ1 of thermal radiation. λ2: Lower limit of detection wavelength, upper limit 0; Angle at which the side wall is viewed from the center of the optical fiber incidence angle (
viewing angle) c,, G2: 1st. This becomes the second radiation constant. That is, the above equation (3) is W2 = f2R(T2) 10l (TI, T2)
・−・・・(3) can be written. Similarly (4
) formula is W3 = f3R (T'3) + G + (TI, "2
) ]-G0 (T2.TA) ・ ・ The tip humidity Tn of (4) can be claimed.

Each of the above-mentioned correction methods is performed by a processing computer, and the corrected tip temperature of each closed-end tube is displayed on the display, and the temperature distribution in the furnace of the HIP device υ is can be defined as iin+.

(Example) Next, a system for carrying out the measurement method according to the present invention will be described.

First, Figure 4 shows an example of the furnace wall of a pressure vessel (Ill.
When a closed 9iM tube 02) is installed through the closed-end tube 02), a detector (13) including a photoelectric converter is installed at the IZJ section between the closed-end tubes, and converts the thermal radiation from the tip of the closed-end tube θ2) into an electrical signal. After converting and amplifying it with an amplifier (14), it is introduced into a computer 05) and subjected to the above-mentioned necessary arithmetic processing, that is, calculation of equation (3), R
(T) is converted to T, and the humidity temperature of the tip HB of each closed-end tube (12) is displayed on the display respectively.

However, when the furnace pressure is actually high (up to 2,000° C. and 2,000 atmospheres), it is nearly impossible to extend the closed-end tube out of the furnace through the furnace wall (II) from the viewpoint of EE Cassir.

Therefore, in such a case, the entire closed-end tube (22) is covered with a heat insulating layer (2
7) The internal crystal [(fixed in the furnace, the closed-end tube (2) and the optical fiber (attached to the closed-end tube opening)
24) to the outside of the furnace through the container lid (in the figure, the lower lid C231), and the detector C25) and computer (
The temperature is measured by a series of measurement systems including 2[il].

In this case, the temperature of the heat radiation led outside the furnace is measured by a radiation temperature sensor having a photoelectric conversion element, usually consisting of an Sb photodiode, etc., and the temperature is converted by known means such as brightness/humidity conversion or two-color temperature calculation. .

In addition, the detection wavelength for radiation temperature drop is 0.3 μm ~
A range of 0.6 μm is effective for temperature measurement.

Figure 6 is a block diagram showing the details of 2(i), which is a calculator θ5 for temperature distribution calculation in the reporter system, which detects the apertures receiving heat radiation from each closed-end tube, and It is shown that the temperature is calculated in divisors using the required electrical and electronic calculation processing circuits according to the configuration and is displayed as temperature.

FIG. 7 particularly shows an example of a heating device in a three-zone heating type H-P apparatus, in this case upper and middle zones.

In order to control the power input to the heaters in the lower three zones, it is necessary to measure the temperature of each zone. Therefore, it is preferable to insert a closed-end tube using the conventionally used thermocouple insertion section. (31+ (35) C, 4(i) set up so that the tips are at 14 points at each excretion level 1; A cavity with a length corresponding to each of the 11I11 wet positions in the second, middle, and bottom three zones (38) (39) (/Itl)
A heat-resistant 4A size (37) equipped with the above-mentioned three closed-end pipes is installed in place of the three closed-end pipes. In particular, the latter has excellent mechanical strength and is easy to pick up and handle.

Fig. 8(a)(b)(c)b] - Fig. 8(a) is a diagram showing an example of manufacturing the closed-end tube shown in Fig. 7(b);
0) is a '-side view.

(c) is a side view, in which the support (4I) is divided into a plurality of parts (41a, ) (4], b) (4], c) (4], cl,
) These are integrally fitted with each other in a concave and convex manner to form an integral closed end tube.

The above is a block diagram of each device part in the measurement method of the present invention, in which a closed IM tube is arranged according to each side as described above, and a detector is directly attached to the opening, or an optical fiber is attached. The measuring method of the present invention is carried out by leading the tube outside the furnace and connecting it to a detector, but the general procedure is as shown in Figure 9. By checking, the temperature at the tip of the closed end tube (er) is displayed, and the start is started again. It is effective in ensuring temperature control in HIP processing by guiding and continuously measuring.

Below is an example of a simulation experiment in which numerical values were actually determined.

Length 17n, inner diameter 10mm, SoC fiber core diameter 4
Using a 00 μm closed-end tube, the temperature at the tip is 2000°C, the end opening temperature is 500°C, and the side wall temperature is from 500°C to 2000°C.
We investigated the case where the temperature changes linearly to °C.

The result is that when converting the thermal radiation power (energy) for the tip and side wall base into the optical fiber into a net temperature, the detection wavelength is 0.9 μm for a tip temperature of 2000°C.
At about 200°C, a temperature measurement error of about 20°C occurred at a detection wavelength of 0.4 μm. However, it has been found that by using the correction method described above, these errors can be eliminated and the influence of the sidewalls can be eliminated.

In addition, the temperature at the lower end of the closed-end tube is fixed at 300°C, and the humidity gradient shown in the dotted line in Figure 10, which connects the temperature at the lower end of the closed-end tube in a range of 1000°C to 2500°C, and the 1:' end temperature in a plane line. Suppose you have .

The results were as shown by the dotted line in Figure 11.

Therefore, when calibrating the entire zero-wet yarn, a realistic calibration curve corresponding to the dotted line in Figure 11 will be obtained, and we will consider the case where the center of the closed-end tube is heated 200°C more than the tip. For example, when the temperature at the tip is 1500° C., the radiation power at 111 indicated by (-) in the figure increases due to central heating, and comes to the position shown by the solid line in FIG. 11.

Therefore, if this increased radiant energy, ie, radiant power, is directly converted to the temperature using the dotted line curve in Figure 11 without compensating for it, the temperature will be approximately 1'700°C.

In other words, the temperature output is 1y, which approximately corresponds to the humidity in the central part,
This results in an error of -12001:: with respect to 500 DEG C. of the tip, making it impossible to obtain an accurate temperature distribution in the furnace, resulting in non-uniformity of the 111P treatment temperature.

However, the correction method according to the present invention solves this problem.

(Effects of the Invention) As described above, the present invention installs a plurality of closed-end tubes of different lengths in a high-pressure furnace of a HIP device, detects heat radiation from the inner wall of the closed-end tubes at the opening of the closed-end tubes, and performs arithmetic processing. This method corrects the temperature measurement error caused by stray light from the side wall of the closed-end tube, extracts only the thermal radiation power at the tip of the closed-end tube, and measures the temperature distribution inside the furnace. pair 1
It is possible to accurately measure temperature over a long period of time by using the HIP device's 1jli' as a temperature distribution measuring means, without having to set the temperature element r- to 11. Since it is determined only by the material, the temperature is about 3000℃! It is possible to get wet, and it is a high school 1! It is extremely effective as a temperature distribution measuring means for AMr river furnaces.

Moreover, since the optical fiber is attached to the closed-end tube opening inside the furnace and guided out of the furnace, it is highly safe.
By adding a correction calculation that eliminates temperature measurement errors due to stray light from the side wall of the closed-end tube, the uL difference is reduced, further improving accuracy and making the temperature distribution in the furnace more uniform in the HIP device. It is the second most useful of all, as it encourages the generalization of HIP in the future.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram to explain the correction method in the measurement method of the present invention, Figure 2 (A), (0), and (C) are explanatory diagrams showing each side of the closed-end tube tip shape, and Figure 3. (a) and (b) are graphs showing revised changes in the side wall crystallinity of closed-end tubes, and Figures 4 and 5 are temperature distributions in the furnace for each role of closed-end tubes.
11jl Block diagram of the fixed system, Figure 6 is a block diagram of the word calculator used in the above system, Figure 7 (a) (b)
(・A schematic perspective view showing an example of installing a closed-end pipe in the three-zone heating method and a perspective view showing another example of the closed-end pipe, Figure 8 (a) middle) (c) In the manufacturing example of the integrated closed i7W tube shown in Figure 7), (a) is a front view, (b) is a top view, and (c) is a side view. Also, Fig. 9 is a flowchart for measuring 1'lF outside temperature in the measurement method of the present invention, Fig. 10 is a diagram showing the relationship between the distance from the end opening of a closed-end tube and temperature, and Fig. 11 shows that there is a high temperature region in the middle part. It is a chart showing the relationship between the incident power and the thermal radiation power incident on the fiber in a certain case. (1, 1) (2++... Furnace wall of high pressure vessel. (+2) (231 (34) (', 351 (36)
...Closed end tube. (12)...Detection W, Q→...Amplifier. (+5) (26)...Word calculator. (3]+ (321+33)... Heater. (41)... Support body. Figure q

Claims (1)

[Claims] 1. High 1. A heat insulating layer and a heating device are placed in the E container,
In a hot isostatic pressurizing apparatus configured to form a Viceroy furnace for accommodating a workpiece and subjecting the workpiece to hot isostatic pressing (E-processing), a 1iJ distribution furnace is equipped with a plurality of closed ends of different lengths. Insert and install the tubes, and keep the tip of each closed-end tube in equilibrium with the surrounding temperature.
In addition, each heating zone is positioned so as to radiate heat radiation into the inside of the closed-end tube, and the tip entrance part of the optical fiber is placed at the opening of each closed-end tube, so that the light radiated from the inner wall of the tip of the closed-end tube is placed. The light receiving FRF capacity is set, and the rear end of the output side is taken out of the high-temperature container, and the thermal radiation power from the inner wall of each closed-end tube is detected by a measurement system connected to the end of each output section, and the power is input into each optical fiber. A correction calculation process is performed to subtract the thermal radiation power from the inner wall of the closed-end tube, and the temperature due to the heat radiation power from the tip of the closed-end tube in each heating zone in the furnace is extracted and the temperature is calculated by the heat radiation power in the furnace. A method for measuring the humidity distribution in a furnace in a hot isostatic pressurizing device, which is characterized by measuring the temperature distribution in a zone. 2. The closed-end pipe is inside the high-pressure vessel.”5. middle, bottom
. 2. A method for measuring temperature distribution in a furnace in a hot isostatic press apparatus according to claim 1, wherein the distal end portion is located in each heating zone corresponding to the separately installed heating apparatus. 3. A method for measuring the temperature distribution in the furnace in the hot isostatic pressurizing device according to item 1 or 2, in which the closed-end tube is made of heat-resistant mutually bonded material.