Explosion-proof electrical equipment housing
The purpose of using fabric sandwiched rubber sealing material is to increase the stiffness and strength of the sealing ring, prevent rubber extrusion, and make it suitable for high pressure. At the same time, in the process of wear, rubber wears ahead of fabric. When the rubber of the parts with high contact pressure wears off, the wear extends to the parts with low contact pressure, so that the wear of the whole sealing surface tends to be uniform, but the friction does not change significantly. However, the lip of the rubber sealing ring sandwiched with fabric can easily scrape off the oil film on the sliding surface, so the lubricity is worse than that of leather and polytetrafluoroethylene. DG Zhongxingshun Sealing Products Factory , https://www.zxs-seal.com
a. 1, IIA device is 200μJ;
b. IIB device is 60μJ;
c. The IIC device is 20 μJ.
(2) The time interval between the de-energization and opening of the electrical equipment enclosure with built-in electric heaters and snap-action door or cover structure shall be greater than the time required for the heater temperature to fall below the maximum allowable surface temperature of the electrical equipment.
For specified time intervals, a warning sign must be provided.
(2) Plastic Enclosures If the electrical device is a plastic enclosure, its plastic enclosure must be able to withstand a variety of performance tests: it is subjected to an impact test as specified. The second test is for thermal stability test. In order to ensure the normal operation of the plastic shell, do not accumulate dangerous static electricity, the determination of the insulation resistance of the plastic shell. The insulation resistance value of the tested plastic surface must not exceed 1×109Ω. Other measures may also be adopted, such as: reasonable design of the housing size, shape, arrangement, etc., grounding of the housing, and the like. Plastic housings must also be made of non-flammable materials.
(3) Cases for type I portable or stand-type drills (and their accompanying latches), portable instrumentation instruments, lamps, etc., of aluminum alloy enclosures and enclosures for type II electrical devices, with tensile strength not less than 120 MPa and magnesium content not Made of greater than 0.5% (weight ratio) of aluminum alloy. It is also possible to protect the surface of the casing with a certain thickness of a synthetic resin film with strong durability, or to protect the casing in a holster so as to avoid the occurrence of dangerous mechanical sparks.
The aluminum alloy housing must also withstand the specified impact test.