JP3396418B2 - Temperature measurement system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring system for measuring the temperature of radiant heat received by a mesh formed by weaving thin gold-plated wires used for a radio wave reflecting surface of an antenna.

[0002]

2. Description of the Related Art A parabolic antenna used in an artificial satellite needs to be made lighter in weight in order to increase its size. Therefore, in such an antenna, as shown in FIG. 3, the mesh 30 produced by braiding fine wires is used.
1 is used as a reflection surface of a radio wave. Then, by connecting a wire to a predetermined position of the mesh 301 and pulling the wire in a predetermined direction, the surface of the mesh 301 has a predetermined curvature. As shown in the enlarged view of FIG. 3B, the mesh 301 is knitted with a fine wire 302 having a thin film of gold (gold plating) formed on the surface of a molybdenum wire so that the mesh size is, for example, about 2 mm. ing. In addition,
The size of the mesh (mesh) is appropriately changed according to the wavelength of the radio wave with which the antenna is symmetric.

As described above, the mesh constituting the reflecting surface is made by knitting fine metal wires having a mesh (mesh) size of about 2 mm. Therefore, if the fine wire surface is not slippery, the mesh should be uniformly knitted. Becomes difficult. Also,
At the intersections of the thin wires that form the mesh, the intersecting thin wires must be electrically connected to each other, and the contact state at the intersections must be good. Therefore, as described above, it is necessary to keep the gold thin film formed on the surface of the thin metal wire by plating or the like. By forming the gold plating film, slip between the thin wires is improved, and it becomes easy to uniformly knit the mesh. In addition, since no natural oxide film is formed on the gold surface, good contact can always be obtained at mesh intersections. That is, a gold thin film is formed on the surface of the thin wire in order to make the surface of the thin wire smooth so that the mesh can be easily knitted (facilitating manufacture) and to keep the contact state between the thin wires at the mesh intersections always good. I am trying.

By the way, since such an antenna is used in outer space outside the atmosphere, its mesh has a heat input due to radiation from the sun, and when it receives sunlight directly, the temperature is about 230 ° C. It is estimated that the temperature is high. As described above, when the temperature of the mesh becomes high, the cable or the like connected to maintain the shape of the mesh surface may melt, and the shape of the mesh surface may not be adjustable. Further, since the mesh temperature becomes high, the influence of the radiant heat from the mesh may act on other devices, resulting in a rise in their temperature. For this reason, it is necessary to measure in advance how high the mesh formed by the thin wire on which the gold thin film is formed becomes when the mesh is exposed to sunlight outside the atmosphere. In this temperature measurement, prepare a thermocouple with the same diameter as possible as the thin wires that make up the mesh, and make an experimental device arranged so that the thermocouple is entangled with the same mesh as that used for the antenna, The temperature was measured.

[0005]

However, the conventional method has a problem that the temperature of the mesh cannot be accurately measured. Although the mesh is composed of thin wires on which a gold thin film is formed, the surface of the thermocouple is a different metal that is not gold. Therefore, when this is exposed to sunlight, the measured temperature is significantly different from the actual mesh temperature because the surface characteristics are different. Then, heat is exchanged between the thermocouple wire and the mesh element wire, and the problem occurs because the measured temperature shows an intermediate value between the two temperatures.

The present invention has been made in order to solve the above problems, and when a fine wire mesh formed on the surface of a thin gold film used for the reflecting surface of an antenna receives radiant heat. The purpose is to be able to measure the temperature accurately.

[0007]

Means for Solving the Problems The temperature measuring system of the present invention has a mesh formed by weaving a thin wire having a predetermined wire diameter and a gold thin film formed on the surface, and a wire diameter similar to that of the thin wire. And a thermocouple with a gold thin film formed so as to cover the connection point part that will be the temperature measurement part, arrange the thermocouple so that the connection point is located on the surface of the mesh, and the thermoelectromotive force of the thermocouple The temperature of the radiant heat received by the thin wire is measured by measuring. With the above configuration, the state in which the connection point of the thermocouple receives the radiant heat is substantially the same as the state in which the thin wires forming the mesh receive the radiant heat.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram for explaining a temperature measuring system according to an embodiment of the present invention.
In this embodiment, first, experimental equipment for temperature measurement is manufactured as shown in FIG. This experimental device has a mesh 101 woven in a frame 100 in the same manner as the radio wave reflection surface of the antenna.
Is attached. The thermocouple 102 is arranged so as to be entwined with the mesh 101. The mesh 101 is formed by knitting a fine wire having a gold thin film formed on the surface of a molybdenum wire having a diameter of about 30 μm by plating so that the mesh size is about 2 mm. It has the same configuration as.

The thermocouple 102 has a terminal 103.
Is connected to the compensating lead wire 104 and is connected to a device (thermocouple potential measuring device) for measuring thermoelectromotive force, which is not shown in the figure. Further, the terminal 103 is provided with a thermocouple 105 for measuring the temperature at that location. Further, in this embodiment, the gold thin film is formed so that at least the joint portion of the connection point 102a, which is the temperature measuring portion of the thermocouple 102, is entirely covered. This gold thin film may be formed by plating, for example. Then, the gold thin film is formed to have a thickness of 1/10 or less of the diameter of the thermocouple. Experiments have revealed that an error occurs in the thermoelectromotive force if a gold thin film is formed too thick at the connection point 102a of the thermocouple 102, but the error does not occur if formed thin as described above.

By the way, the thermocouple can be manufactured by welding two kinds of metal wires, but it is not easy to weld a metal wire having the same thinness as the thin wire of the mesh 101. In order to weld such a thin metal wire, the amount of metal dissolved at the time of welding must be controlled in units of μm. Also,
Even if welding is possible, the welded portion becomes a ball shape, and the metal wire is easily broken at the root of the ball-shaped welded portion. On the other hand, by making a thermocouple as shown below, it becomes possible to easily make it as thin as a thin wire.

A method for manufacturing the copper-constantan thermocouple will be described below as an example. First, FIG. 2 (a)
As shown in FIG. 5, a rectangular copper plate 201 and a constantan plate 202, which is an alloy of Ni 45% and Cu 55%, are welded on one predetermined side. Here, due to the welding, the weld boundary 203 portion rises. Next, as shown in FIG. 2B, the surface of the copper-constantan plate 204 is made substantially flat by cutting the raised portion.

Next, as shown in FIG. 2C, the thickness of the copper-constantan plate 204 is reduced to 30 μm by rolling.
To a degree. Then, as shown in FIG. 2D, if the copper-constantan plate 204 is cut into a width of about 30 μm in a direction perpendicular to the line segment of the welding boundary 203, the copper-constantan having a wire diameter of about 30 μm is obtained. Line 205 is formed. Further, the connection point 203a of the copper-constantan wire 205 does not have a ball shape, and a state of a wire diameter of 30 μm is continuously formed from the conductor wire portion to the constantan wire portion.

Then, the obtained copper-constantan wire 2
05, gold plating may be formed on the surface so as to have a film thickness of about 3 μm and used as a thermocouple. The gold plating may be formed so that at least the connection point 203a portion is coated, but it is preferable that the entire area of the copper-constantan wire 205 is plated with gold. Since it is not easy to determine the portion of the connection point 203a in the obtained copper-constantan wire 205, it is more difficult to apply gold plating only to the connection point 203a portion. Further, if the entire area of the copper-constantan wire 205 is plated with gold, the copper-constantan connection point is formed even if the copper wire portion and the constantan wire portion of the copper-constantan wire 205 come into contact with each other except at the connection point 203a. It will not be done.

By the way, the copper-constantan wire 205 has a very small wire diameter of about 30 μm. For this reason, it is not realistic to extend the thermocouple formed by the copper-constantan wire 205 to a thermoelectromotive force measurement location that is separated to some extent. Therefore, as described above, it is better to replace it with the compensating lead wire from the middle and lead it to the measurement site of the thermoelectromotive force. Below, using the experimental equipment shown in FIG. 1, the thermocouple 1
No. 02 will be described for temperature measurement when the entire area is gold-plated and the compensation lead wire 104 is used. First, the mesh 101 of the experimental equipment shown in FIG. 1 is arranged so as to directly hit the sunlight, and the compensating lead wire 104 and the thermocouple 1 are arranged.
05 is connected to a thermocouple potential measuring instrument.

In the configuration of the experimental equipment shown above, the thermocouple 102 includes the connection point 102a which serves as a temperature measuring section and the thermocouple 1.
02 generates a thermoelectromotive force proportional to the temperature difference from the reference point connected to the compensating lead wire 104. Here, the reference point is virtually provided in the thermocouple potential measuring device, and the thermoelectromotive force of the thermocouple at 0 ° C. is set at this virtual reference point. Then, by converting the thermoelectromotive force difference into temperature, the temperature of the radiant heat received from the sun at the thermal connection point can be measured.

First, the thermocouple 10 at the connection point 102a.
The electromotive force of 2 is E1 = Eb (TH-TM), and the electromotive force at the connection point between the thermocouple 102, the compensating lead wire 104 and E2 is E2.
= Ea (TM-TC). Here, TC is the temperature at the reference point, which is 0 ° C. here. Further, TM is a connection point between the thermocouple 102 and the compensating lead wire 104 (terminal 1
03 position), and TH is the temperature at the connection point 102a. Also, Ea is the relationship between the temperature difference between the thermocouple 102 and the compensating lead wire 104 and the electromotive force, and Eb is the relationship between the temperature at the connection point 102a of the thermocouple 102 and the electromotive force.

Therefore, in the thermocouple potential measuring device, the potential E obtained from the compensation lead wire 104 is E = E1 + E2 =
It becomes Eb (TH-TM) + Ea (TM-0). Here, the electromotive force E2 = Ea (TM-0) at the connection point between the thermocouple 102 and the compensating lead wire 104 is also the electromotive force at the temperature measurement point (connection point) of the thermocouple 105. Therefore, thermocouple 1
By measuring “E2 = Ea (TM-0)”, the temperature T at the position of the terminal 103 was measured.
M is required. Since "E = Eb (TH-TM) + E2" according to the potential measurement result of the thermocouple 105, its temperature TM, and the potential obtained from the compensation lead wire 104, the temperature of the connection point 102a is "TH = ( E-E2) / E
b + TM ”.

[0018]

As described above, according to the present invention, a mesh formed by weaving a thin wire having a predetermined wire diameter and a gold thin film formed on the surface thereof, and a wire having the same wire diameter as the thin wire are formed. It has a thermocouple with a gold thin film formed so that the connection point that will be the temperature measurement part is covered.The thermocouple is arranged so that the connection point is located on the mesh surface, and the thermoelectromotive force of the thermocouple is measured. By doing so, the temperature of the radiant heat received by the thin wire was measured. With the above configuration, the state in which the connection point of the thermocouple receives the radiant heat is substantially the same as the state in which the thin wires forming the mesh receive the radiant heat. As a result, according to the present invention, it is possible to accurately measure the temperature when the mesh formed by the thin wire formed on the surface of the gold thin film used for the reflecting surface of the antenna receives the radiant heat.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining a temperature measuring system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a method for producing a thermocouple.

FIG. 3 is an explanatory diagram showing a mesh used for a radio wave reflection surface of a parabolic antenna.

[Explanation of Codes] 100 ... Frame, 101 ... Mesh, 102 ... Thermocouple, 10
2a ... Connection point, 103 ... Terminal, 104 ... Compensation lead wire, 105 ... Thermocouple.

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-2-219307 (JP, A) JP-A-4-192379 (JP, A) JP-A-61-105300 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G01K 7/02 G01K 1/14 H01Q 19/12

Claims (2)

(57) [Claims] 1. A mesh formed by weaving a thin wire having a predetermined wire diameter and a gold thin film formed on the surface, and a connection point portion formed to have a wire diameter similar to the thin wire and serving as a temperature measuring section. A thermocouple in which a gold thin film is formed so as to be covered, the thermocouple is arranged so that the connection point is located on the surface of the mesh, and the thin wire is obtained by measuring the thermoelectromotive force of the thermocouple. A temperature measurement system characterized by measuring the temperature of radiant heat received by a user. 2. The temperature measurement system according to claim 1, further comprising a compensation lead wire connected to the thermocouple, and measuring the electromotive force of the thermocouple via the compensation lead wire.