SU922539A1 - Device for measuring temperature - Google Patents

Description

(54) DEVICE FOR TEMPERATURE MEASUREMENT

This invention relates to heat-engineering measurements and is primarily intended to measure the temperature of liquid media. A device for measuring the temperature of predominantly liquid media is known, comprising a light source, a temperature-sensitive element optically coupled to a photodetector, the output of which is connected to recorder C-11. The disadvantage of such a device is the accuracy of temperature measurement, which is caused by an uncontrolled change in the transmittance of the optical path, which includes a fiber, adhesive joints, connectors, etc. It is also known a temperature measuring device comprising a light source with an adjustable power supply, a light guide temperature sensor, two photodetectors, the outputs of which are connected to the input of a ratio circuit, and a recorder 21. Such a device significantly reduces the effect of a change in the optical transmittance of the optical path, but does not provide the required accuracy of measurement of fast-changing temperatures due to the significant inertia of the temperature-sensitive element. Closest to the proposed technical entity is a device for measuring temperature, containing a light source with an adjustable power supply, a temperature-sensitive element made in the form of a rod of optically transparent material with a reflective coating on one end and reinforced by another end to a fiber fiber bundle, two photo receivers , the relationship diagram and the recorder 131. However, such a device has low sensitivity, since about half of the luminous flux goes back to the light source, ie reaching the photodetectors.

The purpose of the invention is to increase the sensitivity of the device.

The goal is achieved by the fact that in the device containing a light source with an adjustable power supply unit a thermosensitive element made in the form of a rod of optically transparent material with a reflective cover on one end and fixed with another end to a fiber optic bundle, two photodetectors, a ratio circuit and a recorder the fiber optic cable is made with a common free end facing one of the photodetectors mounted within the aperture angle to its optical axis and directly to the ends of two additional light guides connected to a light source and another photodetector.

Making the fiber of the fiber bundle with a common free end, unlike the known one, in which the free end of the fiber optic bundle is ramified into two arms and introducing additional light guides, while maintaining the intensity of the constant component of the light flux past the temperature sensor and entering one of the photodetectors, the losses can be eliminated luminous flux carrying information about the temperature and arriving at the second photodetector.

The drawing shows a diagram of the device.

The device for measuring temperature contains a light source 1, photodetectors 2 and 3, a temperature-sensitive element 4 in the form of a rod of optically transparent material with a reflective coating 5 on one end, a fiber optic bundle 6, additional light guides 7, a ratio diagram 8 and a recorder 9.

The length of the additional light guides is selected in the range of 1-3% with respect to the length of the entire fiber optic path.

The device works as follows.

The light flux from the light source 1 is transmitted through the light guide 7 to the fiber optic bundle 6 and further to the thermosensitive element. Part of the rays falling on the side gras

no rod i | at an angle smaller than the critical angle of total internal reflection, it refracts and goes beyond it.

A portion of the луч rays is reflected only from the coating 5 and forms at the free end of the optical fiber bundle 6 a constant component of the luminous flux that does not depend on the measured temperature. This part of the rays arrives at the common end of the light guides 7 and about half of the luminous flux of the constant component goes to the photo-receiver 2.

Part of the rays that have passed through the rod C undergoes total internal reflection on its lateral faces and carries information about the magnitude of the measured temperature. This part of the rays comes out of the rod k through the same fibers of the harness 6, and the photoreceiver 3 receives not 50 of this part of the luminous flux, in the known device, but 100%.

Since the measured temperature is judged by the ratio of the intensities of the two components of the luminous flux (at the output of the ratio diagram 8) that has passed the thermosensitive element, the resulting sensitivity of the proposed device is twice as high as the known one.

Increasing the sensitivity of the device allows to significantly improve its metrological characteristics.

Claims (1)

Invention Formula A temperature measuring device containing a light source with an adjustable power supply, a temperature-sensitive element made in the form of a rod of optically transparent material with a reflecting coating on one end and reinforced with another end to a fiber-optic bundle, two photodetectors, a relationship diagram and a recorder, distinguished by that, in order to increase the sensitivity of the device, the fiber optic bundle is made with a common free end facing one of the photodetectors installed within the aperture angle and to its optical axis, and directly to the ends of two additional optical fibers connected to the light source and another photodetector. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 613215, cl. Q 01 K 11/00, 1975. 7 7 t TITgPtN2. USSR Author's Certificate in Application No. 27395 3 / 18-10, 03.20.79. 3. USSR author's certificate in application number 27630Y / 18-10, 10.05.79 (prototype). -five