JPS59203930A - Method for measuring temperature - Google Patents

Abstract

PURPOSE:To make a thick wiring bundle unnecessary and to prevent the erroneous measurement by making a temp. measuring part to the structure capable of giving the deformation according to the temp. variation against an optical fiber by thermo-sensitive member actuating in accordance with the temp. variation. CONSTITUTION:A part for measuring temp. (temp. measuring part) 1 is arranged on the optical fiber positioned at the place where the temp. is to be detected. The optical fiber A is passed through a part 2 for guiding the optical fiber, entered the part 1, passed through a part 3 for guiding the optical fiber and led to an outer part. In the part 1, the fiber A is interposed between two sheets of bimetal 4. If the part 1 is heated in this case, the bimetals 4 are deformed, and the fiber A deforms corresponding to the deformation of the bimetals 4. In such a constitution, the thick wiring bundle is made unnecessary, and the erroneous measurement can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a temperature measurement method for measuring the temperature at a measurement point of a part having a location whose temperature is to be detected over a long period of time. For example, specifically, the present invention relates to a method of measuring temperature at multiple points over a long section, a method of measuring temperature inside a tunnel such as a coal mine, and the like.

DESCRIPTION OF THE PRIOR ART Measuring temperatures as described above has traditionally required the wiring of many thermocouples.

In particular, in order to measure the temperature at multiple points over a long section, a pair of thermocouples (compensating conductors) are required for each point, and it is necessary to bundle many wires and use them over a long section. It had been.

In addition, in order to add more measurement points, a new long section of thermocouple wiring was required.

In addition, thermal lightning pairs are susceptible to electrical induction, and as a result, there is a risk of erroneous measurements when measuring temperatures in locations susceptible to electrical induction. Generally speaking, it has been impossible to measure the temperature of current-carrying objects using conventional thermocouples due to their tendency to be easily influenced by electricity.

Purpose of the Invention This invention was made in view of the above-mentioned situation, and its main purpose is to eliminate the need for thick wiring bundles even when measuring temperature at multiple points over a long section, and to It is an object of the present invention to provide a ms6 method that allows new additions to be easily made, and that does not cause erroneous measurements even when measuring temperatures in places susceptible to electrical induction.

Simply put, this invention is a temperature method that measures temperature using an optical fiber that passes through a location where the temperature is to be detected.

The above objects and other objects and features of the invention will become more apparent from the following detailed description.

Structure and Effects of the Invention The temperature measuring method according to the present invention measures temperature using an optical fiber passing through a location where the temperature is to be detected.

Then, a temperature measuring section is placed on the optical fiber located at the location where the temperature is to be detected. This temperature measuring section is configured to be able to deform the optical fiber in accordance with changes in temperature by means of a temperature sensing member that operates in accordance with changes in temperature. In this way, the concentration at the measurement point is measured by measuring the loss of transmitted light or the change in reflected light caused by the deformation of the optical fiber in response to temperature changes.

As described above, according to the present invention, a side baffle portion having a structure capable of deforming an optical fiber in accordance with a temperature change is disposed on the optical fiber, and the side baffle portion is disposed on the optical fiber to prevent deformation caused by deformation of the optical fiber. This method measures temperature by measuring the loss of transmitted light or changes in reflected light, so even when temperature measurement is required at multiple points over a long period, it is not possible to There is no need for thick wiring bundles for thermocouples, just a compact fiber optic cable. Additionally, new measurement points can be easily added. This is because, in such a case, it is only necessary to place the temperature measuring part on the optical fiber located at the point to be measured. Furthermore, since the method uses an optical fiber to obtain one temperature, rather than using a thermal lightning pair as in conventional temperature measurement methods, electrical induction can be easily detected when measuring temperature. As a result, it becomes possible to reduce as much as possible the erroneous measurements that have occurred in the past. Furthermore, since optical fibers are not subjected to electrical guidance, it becomes possible to measure the temperature of current-carrying objects, which was previously considered impossible.

In one embodiment according to the invention, the temperature-sensitive member is operated by utilizing the shape-changing properties of the shape-memory alloy member due to changes in temperature. Preferably, a combination of a shape memory alloy member and a spring material is used as the temperature sensitive member. In this case, it is desirable that the combination of the shape memory alloy member and the spring material be adjusted so that the amount of displacement of the shape memory alloy member changes continuously in response to changes in temperature. This is because by doing so, the temperature measurement at the measurement point becomes more accurate.

In order to sensitively sense loss due to deformation of the optical fiber, the optical fiber used to carry out this invention has a refractive index difference of 4 between the maximum refractive index part at the center and the minimum refractive index part at the outer periphery. % or less is preferable.

Examples Example 1 As shown in FIG. 1, a measurement system was prepared for measuring temperature using an optical fiber A passing through a location where the temperature was to be detected. A temperature measuring section (temperature measuring section) 1 is arranged on the optical fiber located at a place where the temperature is to be detected. The structure of the temperature measuring section 1 is shown in FIG. As shown in the figure, the optical fiber A enters the temperature measuring section 1 through the optical fiber guide section 2, and is guided to the outside through the optical fiber guide section 3.

Inside the temperature measuring section 1, the optical fiber A is sandwiched between two bimetals 4. Bimetal 4 has a linear shape at room temperature, so two bimetal 4
The optical fiber A sandwiched between the two is in a linearly extended state at room temperature. The state shown in FIG. 2 is a state in which the temperature measuring section 1 is heated. As shown, when the temperature measurement part 1 was heated, the bimetal 4 was deformed. This amount of deformation increased as the heating temperature increased. The optical fiber A was deformed in accordance with the deformation of the bimetal 4. In this way, a loss began to occur in the optical fiber A, and by measuring this loss rate, it was possible to measure the temperature at the measurement point 1.

Example 2 The two bimetals 4 shown in the second factor were made into two members made by overlapping shape memory copper alloy (Cu-zn-A I-alloy) and phosphor bronze (usually spring vI). Replaced. The reverse transformation temperature of the shape memory alloy member is 30° C., and this member is subjected to shape memory treatment so that it bends at right angles on the high temperature side.

However, the @temperature member, which is a combination of a shape memory alloy member and a spring material, normally operated so that the bending angle gradually increased as the temperature rose when the temperature was 30° C. or higher due to the presence of the spring material. In this way, as in Example 1, from 30°C to
It was possible to measure the temperature in a temperature range of 90°C by measuring the loss rate of the optical fiber.

Example 3 A concentration measuring section shown in FIG. 3 was manufactured. In the figure,
The optical fiber A enters the temperature measuring section 1 through the optical fiber guide section 2 and is guided to the outside through the optical fiber guide section 1 3. The optical fiber A located in the temperature measuring part 1 is adapted to be deformable by the moisture sensitive member B and the fixed support part 5. The temperature-sensitive member B is made of shape memory base metal (Ni Ti
It is a combination of a coil 6 made of a stainless steel spring material and a coil 7 made of a stainless steel spring material, and has a moving point 8 for bending deformation at the tip thereof, and further has a screw 9 for fine coil length adjustment. There is.

The shape memory alloy coil 6 has its reverse Il temperature set at minus 50° C., and is subjected to shape memory treatment so that a contractile force is generated when the temperature exceeds this temperature. The stainless steel coil spring 7 generates a force in the direction of extension, and the balance of force between the coil spring 7 and the shape memory alloy coil 6 is adjusted by a minute coil length adjustment screw 9.

In this way, when the temperature at the measurement point was changed in the range of -50°C to room temperature, the bending deformation moving point 8 attached to the tip of the temperature sensitive member B was deformed in accordance with the change in the optical fiber Ar of 8 degrees. By measuring the loss in the optical fiber that occurs at this time using a measurement system as shown in FIG. 1, it was possible to measure the temperature at the measurement point.

A large number of temperature measurement units 1 as shown in FIG. 4 were arranged at regular intervals on the same optical fiber cable A. In FIG. 4, the optical fiber A is bent so as to make one rotation within the temperature measuring section 1. In FIG. A protective round bar 11 is arranged inside the bent portion 10. The curvature of the bent portion 10 of this protective round bar 11 is reduced, and therefore the optical fiber A
It works to prevent the kink from breaking.

As shown in the figure, the temperature-sensitive member B was arranged so that the curvature of the bent portion 10 could be changed. The temperature-sensitive member B is a combination of a shape memory alloy coil 12 and a normal spring material coil 13, and the force balance between the shape memory alloy coil 12 and the normal spring material coil 13 is achieved by an adjustment screw 14. . The shape memory alloy coil 12 is Cal-7n.
-An Al-based shape memory alloy was used. The temperature sensing member B is
It was set so that its length would increase when the temperature reached 100°C or higher. In this way, by transmitting pulsed light from one end of the optical fiber and receiving the reflected light, it was possible to determine measurement points where the temperature was 100° C. or higher.

In principle, shape memory alloys are sensitive to temperature at one point, but if the structure is such that a spring material blocks the recovery force of the shape memory alloy that occurs at a temperature higher than the reverse transformation point of the shape memory alloy, the reverse The amount of the shape opening Ii can be changed according to the increase in moisture level from the transformation point.

[Brief explanation of the drawing]

1 to 4 are diagrams for explaining the present invention in detail. FIG. 1 is a diagram showing an example of a temperature measuring device that measures temperature using an optical fiber that passes through a location where the temperature is to be detected. FIG. 2 is a diagram showing an example of a humidity measuring section disposed on an optical fiber. FIG. 3 is a diagram showing another example of a temperature measuring section disposed on an optical fiber. FIG. 4 is a diagram showing still another example of a temperature measuring section disposed on an optical fiber. In the figure, A is an optical fiber, B is a temperature sensitive member, 1 is a temperature measuring part, 4 is a bimetal, 6 is a shape memory alloy coil, 7
Shows a spring material coil. Patent applicant Sumitomo Electric Industries, Ltd. Z1 diagram

Claims (4)

[Claims] (1) A temperature measurement method that measures temperature using an optical fiber passing through a location where the temperature is to be detected, in which a temperature measurement unit is placed on the optical fiber located at the location where the temperature is to be detected, and 11 above. The section is structured to be able to deform the optical fiber according to the change in temperature by a temperature-sensitive member that operates according to the change in temperature, and measures the loss of transmitted light caused by the deformation of the optical fiber. A method for measuring temperature, characterized in that 8i degrees is measured by measuring changes in reflected light. (2) The temperature measuring method according to claim 1, wherein the temperature sensing member is operated by utilizing the shape change characteristics of the shape memory alloy member due to temperature changes. (3) The shape memory alloy member is provided in combination with a spring material so that the amount of displacement thereof changes continuously according to changes in humidity. Temperature measurement method. (4) The optical fiber has a refractive index difference of 4% or less between the maximum refractive index part at the center and the minimum refractive index part at the outer periphery of the optical fiber. 111m method according to any one of.