Working principle

The structure and principle of explosion-proof or intrinsically safe thermal resistors are basically the same as those of prefabricated thermal resistors. The difference is that the explosion-proof or intrinsically safe product junction box (housing) adopts a special explosion-proof structure in the design. The junction box is made of high-strength aluminum alloy die-casting and has sufficient internal space, wall thickness, and mechanical strength. The thermal stability of the rubber sealing ring meets the national explosion-proof standards. So, when the explosive mixed gas inside the junction box explodes, its internal pressure will not damage the junction box, and the resulting heat energy cannot spread or explode outward.

Specification

Range specifications

Note: "t" is the measured temperature of the temperature sensing element,

thermal response time

When there is a step change in temperature, the time required for the output of the thermocouple to change to 50% of the step change is called the thermal response time, represented by T0.5.

nominal pressure

Generally refers to the static external pressure that the protective tube can withstand at room temperature without breaking, and the test pressure is generally 1.5 times the nominal pressure. In fact, the allowable working pressure is not only related to the material, diameter, and wall thickness of the protective tube, but also to its structural form, installation method, insertion depth, as well as the flow rate and type of the measured medium.

Thermocouple insulation resistance

The test voltage for insulation resistance at room temperature is DC 500 ± 50V.

The atmospheric conditions for measuring insulation resistance at room temperature are: temperature of 15-35 ℃, relative humidity of 45%, and atmospheric pressure of 86-106kPa.

For thermocouples with a length greater than 1 meter, the product of the insulation resistance value at room temperature and its length should not be less than 100 M Ω M is: Rr · L>100 M Ω· m L>1m, where: Rr - the insulation resistance value of the thermocouple at room temperature, M Ω; L - the length of the thermocouple, m

For thermocouples with a length ≤ 1 meter, the insulation resistance value at room temperature should not be less than 100 M Ω

Explosion proof type and level group

Explosion proof level group: dIIBT4 or dIICT4, dIIBT6 or dIICT6

Intrinsic safety group: ia Ⅱ BT4 or ia Ⅱ CT4 (multi pair)

Ia Ⅱ BT6 or ia Ⅱ CT6 (multi pair)

Shell protection level IP65

principle structure

The structure and principle of explosion-proof or intrinsically safe thermal resistors are basically the same as those of prefabricated thermal resistors. The difference is that the explosion-proof or intrinsically safe product junction box (housing) adopts a special explosion-proof structure in the design. The junction box is made of high-strength aluminum alloy die-casting and has sufficient internal space, wall thickness, and mechanical strength. The thermal stability of the rubber sealing ring meets the national explosion-proof standards. So, when the explosive mixture gas inside the junction box explodes, its internal pressure will not damage the junction box, and the resulting heat energy cannot diffuse outward for explosion transmission.

Due to the use of the above-mentioned explosion-proof special structure, the product fully complies with the explosion-proof categories of dIIBT4 to dIICT6, ibIIBT4, iaIIBT4, and iaIICT6. As long as users follow the product usage rules, the product can achieve reliable explosion-proof effects.

Model representation