WZP-74A WZP2-74A WZP-84A WZP2-84A Explosion proof RTD

WZP-74A WZP2-74A WZP-84A WZP2-84A Explosion proof RTD

System composition of WZP-74A WZP2-74A WZP-84A WZP2-84A Explosion proof RTD
(1) Thermal resistance temperature measurement system is generally composed of thermal resistance, connecting wire and display instrument. The following two points must be noted:
① The graduation numbers of thermal resistance and 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. See Chapter III of this chapter for details.

(2) Armored thermal resistance armored thermal resistance is a solid body composed of temperature sensing element (resistor), lead wire, insulating material and stainless steel sleeve. Its outer diameter is generally φ 1~ φ 8mm, min φ mm。 Compared with ordinary thermal resistance, it has the following advantages:
① Small volume, no air gap inside, small measurement lag in terms of thermal inertia;
② Good mechanical performance, vibration resistance and impact resistance;
③ Flexible and easy to install
④ Long service life.

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

(4) Through the junction box with special structure, the explosive mixed gas inside the shell of the flameproof thermoelectric resistance will be broken due to the impact of sparks or arcs. The length of the resistance wire must be changed to affect the resistance value. Therefore, it is better to replace the new resistance body. If welding repair is adopted, it can only be used after it is verified to be qualified after welding.

Working principle of WZP-74A WZP2-74A WZP-84A WZP2-84A Explosion proof RTD
The explosion-proof thermal resistance uses the gap explosion-proof principle to design the junction box and other components with sufficient strength to seal all parts that will produce sparks, electric arcs and dangerous temperatures in the junction box cavity. When an explosion occurs in the cavity, it can extinguish and cool through the gap of the joint surface, so that the flame and temperature after explosion cannot be transmitted outside the cavity, so as to measure the temperature.

Installation requirements of WZP-74A WZP2-74A WZP-84A WZP2-84A Explosion proof RTD
Attention shall be paid to the installation of thermal resistance, which is conducive to accurate temperature measurement, safety and convenient maintenance, and does not affect the equipment operation and production operation To meet the above requirements, pay attention to the following points when selecting the installation position and insertion depth of thermal resistance:
1. In order to ensure sufficient heat exchange between the measuring end of the thermal resistance and the measured medium, the position of the measuring point shall be reasonably selected, and the installation of thermal resistance near the dead corner of valves, elbows, pipes and equipment shall be avoided as far as possible
2. The thermal resistance with protective sleeve has heat transfer and heat dissipation loss. In order to reduce the measurement error, the thermocouple and thermal resistance should have sufficient insertion depth:
(1) For the thermal resistance for measuring the fluid temperature in the center of the pipe, the measuring end should generally be inserted into the center of the pipe (vertical installation or inclined installation) If the pipe diameter of the measured fluid is 200mm, the insertion depth of thermal resistance shall be 100mm;
(2) For the temperature measurement of high temperature, high pressure and high-speed fluid (such as main steam temperature), in order to reduce the resistance of the protective sleeve to the fluid and prevent the fracture of the protective sleeve under the action of fluid, the shallow insertion of protective tube or hot sleeve thermal resistance can be adopted The shallow plug-in thermal resistance protection sleeve shall be inserted into the main steam pipe at a depth of not less than 75mm; The standard insertion depth of thermal sleeve resistance is 100mm;
(3) If it is necessary to measure the temperature of flue gas in the flue, although the flue diameter is 4m, the insertion depth of thermal resistance is 1m
(4) When the insertion depth of the measuring element exceeds 1m, it shall be installed vertically as far as possible, or a support frame and protective sleeve shall be installed