The flameproof enclosure is a mechanical structure made of non-metallic materials such as steel plates or cast steels, cast irons, aluminum alloys, stainless steels, and plastics with a certain strength, and has a certain resistance to explosion. However, the form of the interface between the flameproof enclosures is various. The article briefly introduces the flameproof enclosure joint structure and the flameproof enclosure design requirements.
Explosion-proof explosion-proof equipment production requirements
1. The explosion-proof electrical equipment must pass the examination of qualified explosion-proof electrical equipment inspectors to check its safety performance and obtain a certificate of conformity.
2. The cable junction box and cable introduction device are in good condition, complete parts and components, no defects, and the cable connection is firm and reliable. A cable entry device connects only one cable. The difference between the outer diameter of the sealing ring and the inner diameter of the cable-introducing device shall meet the following requirements:
1 When the outer diameter of the seal ring is not more than 20ran3, the inner diameter difference is not more than 1.0rnnl;
2 When the outer diameter of a 124-coal mine electric safety ring is greater than 20mm and not greater than 60mm, the difference in inner diameter between the two is not greater than l. 5mm;
3 When the outer diameter of the seal ring is greater than 60mm, the difference in inner diameter is not greater than 2.0mm. The difference between the inner diameter of the seal ring and the nominal outer diameter of the cable is not greater than 1.0mm.
It is forbidden to pack other things between the cable and the sealing ring. Unused cable entry devices are blocked with steel plates with a thickness of not less than 2.0 mm.
3. The interlocking device has complete functions, ensures that the power supply is turned on without opening the cover, and the cover is opened and cannot be powered on; the internal electrical components and protection devices are intact and reliable.
4. Clearances and creepage distances between the exposed conductive cores in the terminal box shall be specified. The conductive core shall be free of burrs. When the connection nut is tightened, the insulating material cannot be pressed; the internal parts of the enclosure must not be increased.
5. The shell is intact, without cracks and deformation.
6. The flameproof electrical enclosure fasteners, seals, grounding parts are all intact.
7. The gap, effective width and surface roughness of the flameproof joint are in conformity with the regulations, and the screwing depth and engagement count of the screw flameproof structure comply with the regulations.
8. After the power is turned off at the output side of the device, if there are still live parts in the case, install a protective insulating cover on it, and mark the words “charged†to prevent personal electric shock.
9. The grounding wire in the junction box must be longer than the conductive core wire. Even if the wire is pulled off, the grounding wire remains connected; the junction box is kept clean, free of debris and conductive 10. The explosion-proof electrical equipment is installed at the location Dripping water, water, surrounding rock solid; equipment placed perpendicular to the ground plane, the maximum angle of inclination shall not exceed 15.
Flameproof enclosures have a variety of geometries. A large number of theoretical studies and practices have proved that in a flameproof enclosure with the same volume and different shapes, the explosion pressure in non-spherical enclosures is lower than that in spherical enclosures, that is, the explosion pressure of spherical enclosures. The largest, and the cuboid shell explosion pressure is minimal, the explosion pressure within the shell changes with the shape of the container. This is because the explosive pressure is reduced as the surface area of ​​the heat sink is increased. Therefore, it is advisable to use a rectangular shape for the flameproof enclosure so that the explosion resistance of the enclosure can be improved.
The volume of the flameproof enclosure is also the key to designing a flameproof enclosure. Theory and practice have proved that: under all other conditions, the volume of the flameproof enclosure has nothing to do with the explosion pressure inside the enclosure, and the volume has little effect on the pressure. Therefore, in the design and manufacture of flameproof enclosures, it is possible to reduce the volume of the flameproof enclosures on the premise of satisfying the technical requirements of the devices. This not only ensures the explosion resistance of the enclosure, but also reduces the volume, reduces the weight, and is more convenient in the coal mine. Used in special underground environments.
Explosion-proof explosion-proof equipment production requirements
1. The explosion-proof electrical equipment must pass the examination of qualified explosion-proof electrical equipment inspectors to check its safety performance and obtain a certificate of conformity.
2. The cable junction box and cable introduction device are in good condition, complete parts and components, no defects, and the cable connection is firm and reliable. A cable entry device connects only one cable. The difference between the outer diameter of the sealing ring and the inner diameter of the cable-introducing device shall meet the following requirements:
1 When the outer diameter of the seal ring is not more than 20ran3, the inner diameter difference is not more than 1.0rnnl;
2 When the outer diameter of a 124-coal mine electric safety ring is greater than 20mm and not greater than 60mm, the difference in inner diameter between the two is not greater than l. 5mm;
3 When the outer diameter of the seal ring is greater than 60mm, the difference in inner diameter is not greater than 2.0mm. The difference between the inner diameter of the seal ring and the nominal outer diameter of the cable is not greater than 1.0mm.
It is forbidden to pack other things between the cable and the sealing ring. Unused cable entry devices are blocked with steel plates with a thickness of not less than 2.0 mm.
3. The interlocking device has complete functions, ensures that the power supply is turned on without opening the cover, and the cover is opened and cannot be powered on; the internal electrical components and protection devices are intact and reliable.
4. Clearances and creepage distances between the exposed conductive cores in the terminal box shall be specified. The conductive core shall be free of burrs. When the connection nut is tightened, the insulating material cannot be pressed; the internal parts of the enclosure must not be increased.
5. The shell is intact, without cracks and deformation.
6. The flameproof electrical enclosure fasteners, seals, grounding parts are all intact.
7. The gap, effective width and surface roughness of the flameproof joint are in conformity with the regulations, and the screwing depth and engagement count of the screw flameproof structure comply with the regulations.
8. After the power is turned off at the output side of the device, if there are still live parts in the case, install a protective insulating cover on it, and mark the words “charged†to prevent personal electric shock.
9. The grounding wire in the junction box must be longer than the conductive core wire. Even if the wire is pulled off, the grounding wire remains connected; the junction box is kept clean, free of debris and conductive 10. The explosion-proof electrical equipment is installed at the location Dripping water, water, surrounding rock solid; equipment placed perpendicular to the ground plane, the maximum angle of inclination shall not exceed 15.
Flameproof enclosures have a variety of geometries. A large number of theoretical studies and practices have proved that in a flameproof enclosure with the same volume and different shapes, the explosion pressure in non-spherical enclosures is lower than that in spherical enclosures, that is, the explosion pressure of spherical enclosures. The largest, and the cuboid shell explosion pressure is minimal, the explosion pressure within the shell changes with the shape of the container. This is because the explosive pressure is reduced as the surface area of ​​the heat sink is increased. Therefore, it is advisable to use a rectangular shape for the flameproof enclosure so that the explosion resistance of the enclosure can be improved.
The volume of the flameproof enclosure is also the key to designing a flameproof enclosure. Theory and practice have proved that: under all other conditions, the volume of the flameproof enclosure has nothing to do with the explosion pressure inside the enclosure, and the volume has little effect on the pressure. Therefore, in the design and manufacture of flameproof enclosures, it is possible to reduce the volume of the flameproof enclosures on the premise of satisfying the technical requirements of the devices. This not only ensures the explosion resistance of the enclosure, but also reduces the volume, reduces the weight, and is more convenient in the coal mine. Used in special underground environments.
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