This standard specifies the explosion-proof technical requirements, test methods, inspection rules, packaging and storage of industrial thermocouples and thermal resistors (hereinafter referred to as thermocouples and thermal resistors). This standard is applicable to thermocouples and thermal resistors used in factory explosive gas mixtures with an ambient temperature of -20 to 60°C, a relative humidity of no more than 90%, and an atmospheric pressure of 86 to 106KPA. JB 5518-1991 Industrial Thermocouple and Thermal Resistor Explosion-proof Technology JB5518-1991 Standard Download Decompression Password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Technical Conditions for Flameproofing of Industrial Thermocouples and Thermal Resistor Subject Content and Scope of Application
JB5518-91
This standard specifies the flameproofing technical requirements, test methods, inspection rules, packaging and storage of industrial thermocouples and thermal resistors (hereinafter referred to as thermocouples and thermal resistors).
This standard applies to thermocouples and thermal resistors used in factory explosive gas mixture places with ambient temperature of -20～+60℃, relative humidity not more than 90%, and atmospheric pressure of 86～106kPa. 2 Reference standards
GB2900.35
Electrical terminologyExplosion-proof electrical equipment for explosive atmospheresGB3836.1
GB4208
GB6987.16
GB6987.17
GB2829
ZBY301
ZBN11002
ZBN11010
General requirements for explosion-proof electrical equipment for explosive atmospheresExplosion-proof electrical equipment for explosive atmospheresClassification of flameproof electrical equipment "d" enclosure protection level
Basic environmental test procedures for electrical and electronic productsTest Db; Alternating damp heat test methodMetal tension Tensile test method
Chemical analysis method for aluminum and aluminum alloys Determination of magnesium content by CDTA-titration method Chemical analysis method for aluminum and aluminum alloys Determination of magnesium content by atomic absorption spectrophotometry Periodic inspection counting sampling procedure and sampling table Technical conditions and graduation table for industrial platinum thermal resistors Technical conditions for industrial thermocouples
Technical conditions and graduation table for industrial copper thermal resistors JB/T5582-91 Armored thermocouples
ZBY003
3 Terminology
Technical conditions for instrument packaging
The terms used in this standard shall comply with the provisions of ZBY301, ZBN11002, ZBN11010, JB/T5582-91 and GB2900.35 standards.
4 Technical requirements
Thermocouples and thermal resistors shall comply with the requirements of this standard and shall be manufactured and inspected according to the drawings and technical documents approved by the prescribed procedures. 4.1 Appearance and assembly quality
4.1.1 The surface of the junction box shell of the thermocouple and thermal resistor should have the following signs: a. The outside of the junction box should be equipped with a grounding bolt of not less than M4 and marked with the grounding symbol "=b. A clear permanent embossed mark "Ex" and an explosion-proof mark should be set in a conspicuous place on the junction box; C. There should be a clear permanent embossed warning message "Open the cover after power off" on the cover. 4.1.2 The assembly quality of the thermocouple and thermal resistor should meet the following requirements; a. The locking device of the box cover is reliable and effective;
The Ministry of Machinery and Electronics Industry approved JB5518-91 on July 16, 1991bzxz.net
b. The content of the nameplate is correct and the fixation is reliable. The nameplate is made of copper plate or stainless steel plate with a thickness of not less than 0.5mm; 4.2 Shell protection
The shell protection of the thermocouple and thermal resistor should comply with the provisions of GB4208IP54 protection level. 4.3 Wet heat test|| tt||After the alternating damp heat test, the flameproof surface of the thermocouple and thermal resistor should not be rusted. 4.4 Flameproof joint surface structural parameters
4.4.1 Plane, cylinder and stopper flameproof structure 4.4.1.1 The maximum or diameter difference W of the plane, cylinder and stopper flameproof joint surface (see Figure 1) and the minimum effective length L of the flameproof joint surface, and the minimum effective length L from the edge of the bolt through hole to the edge of the flameproof joint surface shall comply with the provisions of Table 1. W
Plane type
bCylinder type
When f≤1.0
Stop type
Otherwise L,=a
L,=a+b
Joint surface form
Plane, cylinder, stop structure
Note: ①The IIC level in the table is applicable to places that do not include acetylene. ②The IIC level shall not adopt a plane explosion-proof structure. JB5518-91
Enclosure volume V(1)(0.1
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