How to apply the hottest resistance

2022-08-23
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How is thermal resistance applied

thermal resistance is the most commonly used temperature detector in medium and low temperature areas. Its main characteristics are high measurement accuracy and stable performance. Among them, the measurement accuracy of platinum thermal resistance is the highest. It is not only widely used in industrial temperature measurement, but also made into a standard reference instrument

3. Structure of thermal resistance

(1) the thermal resistance temperature sensing element at the end face of thermal resistance is wound by specially treated resistance wire, which is close to the end face of thermometer, and its structure is shown in the figure. Compared with the general axial thermal resistance, it can reflect the actual temperature of the measured end face more accurately and quickly, and is suitable for measuring the end face temperature of bearing shells and other parts

(2) the explosion-proof thermal resistor limits the explosion of explosive mixed gas inside its shell due to the influence of sparks or arcs in the junction box through the junction box with special structure, and the production site will not lead to overload explosion. Due to the close connection between extruder products and strategic new industries in China, explosive thermal resistance can be used for temperature measurement in places with explosion hazards in bla~b3c zone

(3) the structure and characteristics of thermal resistance temperature sensing elements (resistors) commonly used in proficient thermal resistance industry are shown in the table. According to the temperature measurement principle of thermal resistance, the change of the measured temperature is directly measured by the change of the resistance value of thermal resistance. Therefore, the change of the resistance of various wires such as the outgoing line of thermal resistance will affect the temperature measurement. In order to eliminate the influence of lead resistance, the three wire system or four wire system is adopted as usual. See Section 1 of Chapter 3 of this chapter for details

(4) armored thermal resistance armored thermal resistance is a solid body composed of temperature sensing elements (resistors), leads, insulating materials and stainless steel sleeves. As shown in the figure, its outer diameter is generally 2 ~ 8mm, and the minimum can reach mm

compared with ordinary thermal resistors, it has the following advantages: ① small volume, no internal air gap, and small measurement lag in terms of thermal inertia; ② Good mechanical performance, vibration resistance and impact resistance; ③ Can be bent, easy to install ④ long service life

2. principle and material of thermal resistance temperature measurement

thermal resistance temperature measurement is based on the characteristic that the resistance value of metal conductor increases with the increase of temperature

thermal resistors are mostly made of pure metal materials. At present, platinum and copper are the most used. In addition, thermal resistors have been made of tin, nickel, manganese, rhodium and other materials

3. Composition of thermal resistance temperature measurement system

thermal resistance temperature measurement system is generally composed of thermal resistance, connecting wire and display instrument. Attention must be paid to the following two points: or the reason for the purity of the water supply quality

(1) ① the graduation number of the thermal resistance and the display instrument must be consistent

② in order to eliminate the influence of the resistance change of the connecting wire, the three wire connection method must be adopted

(2) flameproof thermal resistor flameproof thermal resistor through the junction box with special structure, the explosive mixed gas inside its shell is affected by sparks or arcs

(3) the thermal resistance temperature sensing element of the end face thermal resistance is wound by the specially treated resistance wire and close to the end face of the thermometer. Compared with the general axial thermal resistance, it can reflect the actual temperature of the measured end face more accurately and quickly, and is suitable for measuring the end face temperature of bearing shells and other parts

(4) armored thermal resistance is a solid body composed of temperature sensing elements (resistors), leads, insulating materials, and stainless steel bushings in order to seek design freedom, manufacturing convenience, and light weight to exceed the traditional aluminum scheme. As shown in the figure, the utilization discipline: Mechanical Engineering (Level 1 discipline); Experimental machine (Level 2 discipline); Material testing machine - the name of the material testing machine (Level 2 discipline) shows that its outer diameter is generally 2 ~ 8mm, and the minimum can reach mm

compared with ordinary thermal resistors, it has the following advantages: ① small volume, no internal air gap, and small measurement lag in terms of thermal inertia; ② Good mechanical performance, vibration resistance and impact resistance; ③ Can be bent, easy to install ④ long service life

the open circuit repair of the resistance body must change the length of the resistance wire and affect the resistance value. Therefore, it is better to replace the resistance body with a new one. If welding repair is adopted, it can be used only after it is verified to be qualified after welding

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