About super long temperature sensor calibration standards developed by constant temperature trough

【 Abstract 】 In this paper, we put forward to develop a standard calibration can be super long temperature sensor thermostat design requirements and design train of thought, for research, hope to solve real super long temperature sensor for calibration of sensor is too long and submergence depth is insufficient. 1 introduction

thermostatic bath is a kind of can provide constant temperature field of the tub. Widely used in petroleum, chemical industry, medicine, food, biological engineering, factory laboratory and metering quality inspection departments, etc. As a contact temperature calibration work in the most basic form a complete set of equipment, all kinds of glass thermometers and temperature sensor calibration need it to complete. However, constant temperature trough work area currently used standard 450 mm, maximum depth general for super long ( Generally up to 2000 mm) Platinum thermal resistance, bimetallic thermometer, glass thermometer, armoured thermocouple used for oil, such as optical fiber thermometer used in nuclear power industry, chemical industry and other important place, as an important production safety monitoring and measuring instruments, accuracy of the numerical is an important means to ensure the normal operation of equipment. Using the existing standard thermostatic bath is usually can't satisfy the temperature sensing element exceed 500 m m part and for effective dissemination of traceability.

2 standard system components of thermostatic bath

thermostatic bath is mainly composed of tub, heating module, mixing mechanism, control system and other parts. Its general structure as shown in figure 1.

by internal resistance wire heating or use the compressor to refrigeration, coupled with high stability of platinum resistance P R a T or other temperature sensor, constant temperature trough with precise control at the same time as gentle automatic protection function. In addition, the standard of graphic thermostat for double barrel structure, which is the core of the constant temperature trough implementations of its technical performance. The device heating, mixing is separated from verification thermostatic bath is relatively independent. Inside the barrel is used for heating and stirring, outer barrel used to measure. Medium, barrel after agitator for strong agitation, make temperature is not uniform medium, barrel after full mixing and the medium from the bottom into the workspace (rarely by interference Outer barrels) In the workspace, forming a stable and uniform temperature of the liquid space, in order to obtain good performance.

3 super long temperature sensor calibration standard constant temperature trough the technical difficulties of super long temperature sensor calibration standard thermostat should not only meet the performance requirements for constant temperature trough as standard, and to realize the over-long sensor calibration requirements, will not be able to avoid the following several technical problems to overcome:

( 1) Super-long thermostatic bath tub design: under laboratory conditions, the design has a certain capacity and working depth of up to 2 m, because laboratory space environment at the same time, need tub try to reduce the amount of physical space.

（ 2) On performance parameters, it is necessary to meet the level of working face any two points temperature difference is less than 0. 01 ℃, any two points of different depth temperature difference is less than 0. 02 ℃, at any point in the slot volatility does not exceed 0. 02 ℃, i. e. , to meet platinum resistance verification regulation of constant temperature trough the strict technical requirements.

（ 3) Period of temperature of heating refrigeration and its control, realize temperature control, temperature compensation and satisfy the thermostatic bath as a standard, tub temperature uniformity, stability needs.

（ 4) Have heating, cooling, at the same time, stirring, shock absorption, thermal insulation, such as design, and has good comprehensive performance, can achieve rapid heating, cooling, constant temperature effect, achieve the job requirements of the laboratory.

4 super long temperature sensor calibration standard design idea of constant temperature trough

the ultra long temperature sensor calibration standard thermostatic bath is not completely subvert the traditional constant temperature trough, but through the optimization design and test verification, reference existing constant temperature trough structure, keep vertical tank structure solutions, side-by-side multipole tub design, through the main tank and parallel architecture, oblique opening mode of connection, as much as possible to reduce the increase in horizontal width, extend the working depth of the tub, so as to effectively meet the requirements of submerged depth of the sensor of large, in addition, the use of advanced temperature control device and the mixing technology, comprehensive methods of mechanical vibration, heat preservation, rapid heating, cooling, and temperature compensation, the precision temperature control device such as a modem control and ensure the verification or calibration of super long time to provide a stable temperature, uniform temperature field. The following is a simplified schematic diagram:

5 conclusion

discussed in this paper, the ultra long temperature sensor calibration standard thermostat development train of thought, is based on the measurement work to meet the actual demand. The standard tank can meet all kinds of super long thermometer and sensor calibration work requirements, and can develop standard thermostatic bath market, to reach the domestic advanced level, after the mature can be to the general requirements of measurement unit or organization, has good social and economic benefits, at home and abroad to fill gaps. Relevant product recommendations: magnetic level gauge