JPS6069527A - Apparatus for displaying limit temperature - Google Patents

Abstract

PURPOSE:To display the excess of a limit temp. of an instrument by utilizing a magnetic transfer of a ferrite at Curie point to pull apart a magnet mechanically based on a loss of an attracting force between the ferrite and the magnet when the temp. of the instrement whose limit temp. is to be measured attains to Curie point in the course of the temp. rising. CONSTITUTION:A substrate 30 is stuck to a bottom wall 1 of the instrument whose temp. is to be measured. The magnet 3 is attracted to the ferrite 2 through a spacer 33, and whole or a part of the magnet 3 is shielded by a shielding plate 31. When the temp. of the instrument is elevated above limit temp. by overheating, the ferrite 2 receives a heat through the substrate 30 having high thermal conductivity and the temp. exceeds Curie point, and the magnet 3 falls down on an enclosure 32 by its own weight. Because of this, the magnet 3 is displayed against the outer part. Since the magnet 3 is pulled apart thoroughly from the magnetic wall of the instrument by the substrate 30, mulfunctions are not caused, and the damages of the ferrite are prevented by a spacer 33.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting and displaying the limit temperature of equipment that requires overheating prevention.

Background of the Invention Heavy electrical equipment such as power transmission and distribution, substation, electric motors, home appliances, heating and cooling equipment, kitchen equipment, combustion equipment, chemical reaction equipment, etc.
There is a risk of destroying a part of the device due to overheating, and in this case, the overheating status is displayed.
Display devices that require a power source and display devices that do not have a power source are used. However, since it is desirable that this type of display device be without a power source, various types have been proposed. Among these, contact types include liquid expansion thermometers, temperature-indicating paints, and thermolabels, and non-contact types include infrared thermometers. In addition, liquid expansion thermometers are
It is unsuitable for viewing the temperature of devices located far away, such as transformers or pole transformers, from a distance. Temperature-indicating paints and thermolabels have a wide range of displayed temperatures. Although infrared thermometers can be used to measure temperature remotely, they not only require large-scale equipment but also have the disadvantage of low measurement accuracy.

Purpose of the Invention The present invention provides that when the temperature of a device reaches a critical temperature even once,
An unpowered limit that responds to this by indicating that the temperature of the device has risen above the limit temperature, and can continue to indicate that the limit temperature has been reached even if the wet ash in the device subsequently drops to normal temperature. The purpose is to provide a temperature display device.

Another object of the present invention is to provide an unpowered limit temperature display device whose measurement results can be easily identified even remotely.

It is a further object of the present invention to provide an unpowered limit temperature display device that is more precise than conventional measuring devices.

Summary of the Invention and Effects The device of the present invention uses a ferrite and a permanent magnet as functional components, and utilizes the magnetic transition of the Curie point of the ferrite to increase the temperature of the limit temperature regulator. , when the ferrite in thermal contact with this device reaches the Curie point,
This is a power-free display device that, when the attractive force between the ferrite and the magnet is lost, causes the magnet to be mechanically separated by 1 inch due to gravity, a spring, a pressure difference, etc., and indicates that the temperature limit of the device is exceeded.

According to this device, the Curie point of the ferrite is always constant, so it is possible to display temperature much more accurately than conventional temperature-indicating paints, labels, or infrared thermometers.
Moreover, once the limit temperature is detected, this device keeps the magnet separated from the ferrite, so it has the advantage of displaying that the limit temperature has been reached until proper maintenance and inspection of the device being measured is carried out. . Moreover, since the magnet physically changes its position, the display state can be easily identified even from a distance, such as in circuit breakers, pole transformers, etc., and no power source is required.

However, after careful consideration, it was found that the above-mentioned missing device which utilizes the Curie point of ferrite has several problems. First of all, A4 board is generally used for the outer walls of many power equipment and electrical equipment such as transformers and circuit breakers, and its Curie point is much higher than its limit temperature.
Even if the ferrite loses its magnetism at temperatures above its cue point, the outer walls of the device remain highly magnetic. Furthermore, since ferrite has low thermal conductivity, increasing the thickness will reduce temperature sensing accuracy, so it cannot be made thicker. For these reasons, the attractive force between the outer wall of the device and the permanent magnet was large, causing malfunctions.

Therefore, in the present invention, this problem can be solved by attaching the display device to the wall of the device via a plate or sheet made of a thermally conductive non-magnetic material. In addition, in this device, the limit temperature is displayed by placing the permanent magnet between the ferrite and the limit temperature, so it was found that it was not possible to make a sufficient judgment from a distance due to the distance the permanent magnet had moved. Therefore, another feature of the present invention is to provide a shield for the permanent magnet so that when the permanent magnet is attracted to the ferrite, it is completely shielded from the outside, and when the permanent magnet is separated, the permanent magnet is set to ntb. Solve this problem with leverage.

Furthermore, ferrite made by sintering (and in some cases, permanent magnets are also made of ferrite material) is relatively brittle against external forces, so if it collides with the magnet due to an impact from an external force during assembly, continuous shooting, installation, operation, etc., the ferrite will (or the permanent magnet if the permanent magnet is made of ferrite material). Another feature of the invention solves this problem by providing a spacer between the ferrite and the permanent magnet. Note that the present invention does not need to have all of the above features, but only needs to have at least one feature.

3. Detailed description of the invention The invention will be explained in detail with reference to examples.

The ferrite used in the present invention is a soft magnetic sintered ferrite that sharply loses its magnetism at the Curie temperature during the heating process. Some examples are shown in FIG. These are TDK
It is commercially available under product names such as temperature sensitive core TC40NTC150 (manufactured by TDK Corporation), and the Curie point error is 11.
Generally, an accuracy of ±3°C from 0°C to +150°C, and an accuracy of ±1°C or less is possible depending on the design. It is easy to manufacture ferrite with a Curie point that matches the temperature limit of the equipment under test that requires protection against overheating.

On the other hand, the permanent magnet is selected from magnets such as other sintered magnets such as llalmitzerite or metal magnets such as alnico, whose Curie point is sufficiently higher than that of temperature-sensitive ferrite. For example, Ba ferrite generally has a Tuer point of 400° C. or higher, which is much higher than that of temperature-sensitive ferrite.

Embodiment 1 FIGS. 2 and 3 show a limit temperature display device according to a first embodiment of the present invention. In the figure, numeral 1 indicates the bottom wall of equipment to prevent overheating, such as a circuit breaker or a pole transformer, and is made of a steel plate. 5o is a substrate made of a non-magnetic and highly thermally conductive material that constitutes a part of the display device holder; for example, a metal plate such as brass or aluminum, a thermally conductive plastic plate or sheet, or a thermally conductive material. 2 is a plate-shaped ferrite fixed to a thermally conductive non-magnetic substrate 30, which is defined above and corresponds to the temperature limit of the equipment. and has a predetermined Curie temperature. 3 is a plate-shaped permanent magnet selected from any magnetic material such as Ba ferrite. 7 A non-magnetic shielding plate 3 is placed around the elite 2 and the permanent magnet.
1 as part of the holder. This shielding plate 61 is made of opaque plastic, ceramic, aluminum, or the like. At the lower end of this shielding plate 51 is a transparent glass,
A transparent enclosure made of plastic or the like or an enclosure 32 with a see-through window is provided, and a hole 34 is provided in a portion to serve as an operation hole for the magnet 3. Furthermore, the spacer 33 is connected to the ferrite 2 from the shielding plate 31.
protrude along the surface. As a result, a gap of approximately α5 to 1 mm is formed between the ferrite and the magnet.

In use, first, the substrate 50 of the display device is attached to the bottom wall 1 of the device whose temperature is to be measured using a strong heat-resistant adhesive or other means.
sticks to. Further, the magnet 3 is attracted to the ferrite 2 via the spacer 33 (FIG. 2). At this time, magnet 3
are all or partially shielded by the shielding plate 31. When the temperature of the device rises beyond the limit temperature due to overheating, the ferrite 2 receives heat through the highly thermally conductive substrate 30, and the temperature exceeds the cue point, causing the white dot to rise above the enclosure 32 as shown in FIG. Fall. Therefore, the magnet 3 will be displayed to the outside. Since the substrate 30 sufficiently distances the magnet 6 from the magnetic wall of the device, there is no possibility of malfunction. Also, because of the spacer, there is no damage to the ferrite.

Embodiment 2 FIGS. 4 to 5 show an unpowered limit temperature display device according to a second embodiment of the present invention. In the figure, 1 is the wall of the equipment that should prevent overheating. Reference numeral 30 denotes the non-magnetic and highly thermally conductive substrate described in connection with FIGS. 2 to 5, and is attached to the wall 1 with a strong heat-resistant adhesive or non-magnetic screws. The substrate 60 is partially provided with a holder for holding the plate-like 7-elite 2. In the case of a pole-mounted transformer, the 7ELITE 2 is made of a material having a cue temperature of 105 DEG C. and a sharp transition property as shown in FIG. 1, corresponding to its temperature limit. The ferrite 2 has two holes for accommodating the springs 5, and also has gold, (. These balls 4 protrude downward from these holes.The ends of the balls 4 are stoppers 6 to prevent the magnets 6 from falling off.The strength of the springs 5 is such that the ferrite 2 reaches the Curie point. 0.5-1 for lower temperatures
Magnet 3 is set at a sufficient V with the spacing of the cod! Furthermore, the length of n6 is such that once the ferrite 2 is separated, it will not attract the magnet 3 against the force of the spring 5 even if the temperature reaches below the cue point and the magnetism is restored. It is stipulated that Further, an opaque shielding plate 7 is provided around the ferrite 2 and the permanent magnet 3 as part of the holder, and a spacer 35 is placed along the ferrite 20 surface.

In use, first, the permanent magnet 3 is manually pressed against the ferrite 2 and attracted near the surface of the ferrite 2 by magnetic force. As long as the temperature of the wall 1 of the device under test remains below the cue temperature of the ferrite 2, that is, below the limit temperature of the device under test, the magnet 3 remains in an attracted state (Fig. 4); When the temperature exceeds the limit temperature, the ferrite 2 reaches the curie moisture level and loses its magnetism, so the magnet 3 is separated from the ferrite 2 by the spring 5. (Figure 5). Even if the temperature of the device falls below the limit temperature due to a reduction in power consumption, etc., the magnet 3 will not be returned to its original position because it is sufficiently far away from the 7elite 2 or because of the presence of the spring 5. It is possible to continue displaying that an abnormality has occurred. Therefore, the magnet 32 can only be removed manually after maintenance and inspection.
It can be returned to the original suction position. Further, the function of the board 6o eliminates the cause of malfunction. Moreover, the shielding plate 7 makes the display very easy to see. Further, the ferrite is protected by the function of the spacer 35. As an example, the size of ferrite 2 and magnet 3 is about 30m x 40w, and the thickness is 1Q.
tm, 8tra, the diameter of the two holes of the ferrite 2 is 10 steps ψ, the non-magnetic material 4 is 8 steps ψ, the non-magnetic spring 5'f is used, and the distance between the ferrite 2 and the magnet 3 is α5~
When the temperature was reduced to one, a display device that responded sensitively to the temperature limit was obtained.

Embodiment 3 As shown in FIGS. 6 and 7, a non-magnetic metal plate or a plastic plate 8.
9 are each fixed with a strong heat-resistant adhesive, and one end of the plates 8 and 9 is connected in a hinge manner with a pivot axis of 1°. On the other hand, a stopper 11.12 is provided at the other end G of the plate 8.9, and the distance between the ferrite 2 and the magnet 3 is determined to be about 0.5 to 1. Then, the opposite side of the ferrite 2 is adhered to the non-magnetic gold coin substrate 3°, and the substrate 30 is further attached to the bottom wall 1 of the device with a heat-resistant adhesive. In this example, the same functions and effects as in Example 1 can be obtained. In addition, when the magnet 3 separates from the surface of the ferrite 2, it vertically displays a large area as shown in Fig. 5, which increases the display effect and makes it easier to identify the status of the device from a distance. I can do it.

Example 4 In this example, the weight of the permanent magnet is used without using a spring.

As shown in FIGS. 8 and 9, a non-magnetic material 6 having a nut-shaped stopper 6 at the lower end is fixed at the center of the plate-shaped ferrite 2, and this ball passes through the center hole of the plate-shaped permanent magnet 3 at a true speed. Slidingly guides the permanent magnet. The plate 6 has a stopper 13 on the lower surface of the ferrite 2 with a thickness of about 0.5 to 1 inch. A non-magnetic shielding plate 7 is fixed to the same area of the ferrite 2, and a stopper 14 having the same thickness as the stopper 13 is protruded from the inner surface of the shielding plate. The shield plate has magnet 3 and 7
It has a length that hides the periphery of the magnet 3 at the position where it is attracted to the elite. 7 Elite 2 is the substrate 30 mentioned on the other side
It is supported by a strong heat-resistant adhesive and is bonded to the machine 1 of the equipment to be prevented from overheating.

In use, the stone 3 is manually drawn onto the surface of the ferrite 2. At this time, the spacing between the magnet and the ferrite is determined to be approximately 0.5 to 1 inch by the action of the stoppers 13 and 14 (FIG. 8). When the temperature of the device exceeds the limit temperature, the attractive force between the magnet 3 and the ferrite 2 disappears, and the magnet 3 falls due to its own weight.

As a result, the magnet 3 is completely exposed from the shielding plate 7.
The device status is displayed. The advantages of this example are the same as those of the previous example, as well as the advantage that no spring is required.

Example 5 Please refer to FIGS. 10-12. Arc-shaped permanent +a stones 5 are arranged along the inner circumference of the sintered ferrite 2 formed in an arc shape at intervals of 0.5 to 1 m4Jii degrees, and these are housed in a shallow circular non-magnetic gold 111 case 15. do.

That is, the metal case 15 is provided with an enlarged diameter portion 16 in which the arc-shaped 7elite 2 is housed, and a support pin 17 is stacked in the center of the nurse 15 and a coil spring 18 is fixed around this. Extending spring @19.20
Both ends of the magnet 3 sliding on the cylindrical surface 2° of /r-7, 15 are held down by the magnet 3. The inner peripheral surface of the ferrite 2 is set back a little from the cylindrical surface 20 of the case to create a gap between it and the magnet 6.

A window 21 is formed in the cylindrical part of the case 15, a stopper 22 for the magnet 3 is provided protruding near one end of the window 21, and the elasticity of the spring 18 is appropriately determined so that the magnet 6 is separated from the influence of the ferrite 2. Sometimes it hits the stopper 22 and the window 21
so that it is exposed to The attractive force between the ferrite 2 and the magnet 3 is determined so that when the ferrite 2 is at a temperature below the Curie point and the two are brought close to each other, they will sufficiently attract each other against the force of the spring 18.

Attach the flat side of this display device to the wall of the overheating prevention device using strong adhesive. When the temperature rises beyond the limit temperature of the device, the magnet moves from the position shown in FIG. 10 to the position shown in FIG. 11 due to the magnetic transition of the Curie point of the ferrite 2, and is exposed to the window 21 to display the temperature. Other effects, coloring, display using light using switches, electricity, sound, etc. are the same as in the previous examples.

Variations In all of the above examples, the operating state of the magnet can be more easily identified if the surface of the magnet is colored in a different color than the surrounding elements. Furthermore, if a mirror is attached to a part of the magnet, the state of light reflection changes depending on the position of the magnet, making identification easier. Furthermore, in the example shown in FIGS. 4 and 5 in which a coil spring is used as the spring, the difference in air pressure may be utilized. Further, in the example shown in FIGS. 4 and 5, the spring can be omitted when the device is attached to the bottom wall of the device, and conversely, in the example shown in FIGS. 6 and 7, the spring may be used together with the hinge. In the examples shown in Figures 2 to 6 and 5 to 9, if the display device is used on a part other than the bottom wall of the device, a coil spring or a 9-magnitude spring can be used. The change in position itself was used for display. However, this position change Q
Instead of this display, the present study also includes converting this position change into an electrical signal and displaying it by another means. For example, by switching a switch inserted into a part of an electric circuit by the movement of a permanent magnet, it is possible to light a lamp, issue a buzzer, and operate other control components or safety devices. These display methods can also be used in conjunction with the display of the illustrated embodiment.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the initial magnetic permeability and temperature of temperature-sensitive ferrite used in this book. Figure 2 is a cross-sectional view of the limit temperature display device according to the first embodiment of the present invention. The figure is a cross-sectional view of the display device of the fifth embodiment in which the display device of FIG. 2 is activated, FIG. 7 is a cross-sectional view showing the display device of FIG. 6 in an activated state, and FIG. 8 is the display of the fourth embodiment. Cross-sectional view of the device, No. 9
The figure is a cross-sectional view showing the operating state of the display device of FIG. 8, FIG. FIG. 12 is a perspective view of the display device. The main parts in the figure are as follows. 2: Temperature-sensitive ferrite 6: Permanent magnet 4: Magnet guide rod 5: Spring 7: Shielding plate 8.9: Non-magnetic plate 10: Pivot 11.12.13.14: Stopper 15: Case 17: Shaft 18: Spring 19 .20: Spring end 21: Window 22: Stopper 30: Non-magnetic high heat conductive plate Name of agent: Yui Kurauchi, Hirodo Kurahashi, Akira Kurahashi Figure 2 Figure 3 Figure 12 Procedure amendment patent dated November 4, 1982 Indication of the case of Mr. Yoshio Waka, Director General of the Agency 1981 Patent Application No. 176451, title of the invention Relationship with the case of person correcting limit temperature display device Name of patent applicant (306) TDC Co., Ltd. Agent 〒103 Address □ Contents of Kusunoki's amendment to Detailed Description of the Invention/Brief Description of Drawings in Lr3 of the Small Ja Book The description is amended as follows as shown in the attached sheet. 1. On page 10, line 13, add ``Non-magnetic'' next to ``Support j''. 2. On page 13, line 12 and line 14, correct "6" to "4". 5. In lines 14, 16, and 17 of the same page, the word "stopper" is corrected to "spacer." 4. In the first line of page 14, correct the word ``side'' to read ``example.'' 5. In the fourth line of the same page, replace "stopper" with "spacer"
I am corrected. B In the third line from the bottom of the same page, add ``Non-magnetic'' next to ``J''. Z On page 15, line 15, it says "on a flat surface" and then "
"via the board mentioned in the other example." 8 Divide "13.14" by nu on page 18, line 10. 9 On the 10th line of the opposite page, there is "Stopper", followed by ", 13.
14 nispaca,” he said with zero strength. Figures 4 and 5 have been deleted from the drawings and replaced with Figure 4 of the attached sheet.
Add Figure and Figure 5. Figure 4 Figure 5 5 Procedural amendment November 60, 1988 Director-General of the Patent Office Kazuo Wakasugi Indication of the case 1981 Patent application No. 176451, title of invention Related Patent Applicant Name (306) TDC Co., Ltd. Agent 103 Address Oil and Fat Industry Hall, 3-13-11 Nihonbashi, Chuo-ku, Tokyo Phone: 273-6436 ・1 Name (6781) Patent Attorney Motoki Kurauchi Hiroshi...
−)′・−1−−− Same address Same address as above zJ 忰一→市” 21 sato power increase l mock− Subject of amendment〒Tou I bowl cultivation or boat heat ←l=−1 Invention of the specification→ Contents of amendments to the detailed description of the invention in the Hozen-Seika Harunaga 0 Handbook As shown in Attachment 1, in the 5th line of page 15 of the specification, after ``Move backward'', ``
"By spacer 26," said one person 02. Figures 10 and 11 of the drawings are corrected as shown in the attached sheet. 2″-

Claims (1)

[Claims] 1. A display device that is attached to a part of a device to be measured to measure and display the limit temperature of the device, the device being attached to the device is made of a non-magnetic and highly thermally conductive plate material. a holder including a ferrite attached to the surface of the non-magnetic material and having a Curie point corresponding to the limit temperature of the measuring device; a permanent magnet that is attached to the ferrite so as to be able to be freely attracted to the ferrite; A non-power supply limit temperature display device that displays a limit temperature based on the position of the permanent magnet, the device comprising means for separating the permanent magnet from the ferrite plate when the ferrite loses its magnetism. 2. The limit temperature display device according to the 182nd aspect, wherein the holder includes a shielding plate that shields the permanent magnet at the attraction position and causes N to be emitted at the false position. 5. The permanent magnet is installed in the ferrite with a small distance gi.
1. The limit temperature display device according to claim 1 or 2. 4. The limit temperature display device according to item 2 or 6 above, wherein the permanent magnet is coral-colored. 5. The limit temperature display device according to item 1 or 3, wherein the limit temperature is displayed by an electric signal, light, or sound depending on the position of the permanent magnet.