Explosion-proof camera explosion-proof structure
Electric sparks and arcs can ignite explosive mixtures. The gap-proof structure established by Germany is a reliable method for preventing arcing and the like from igniting the surrounding explosive mixture. Explosion-proof structure of electrical equipment re-explosion dangerous area is widely used, it can not only prevent the explosion of fire, but the shell can withstand a certain overpressure. It has a sufficiently strong outer casing that withstands 1.5 times the maximum explosion pressure of the internal explosive gas mixture and must not be less than 3.5 × 105 Pa, ensuring no deformation or damage, no permanent deformation, and a certain structural clearance for the injection. The resulting combustion products are cooled to a temperature below the autoignition temperature of the external explosive mixture by a certain flange length. The structural gap may be composed of a plane joint surface or a cylinder joint surface, and may also be composed of a curved path, a thread or a barrier structure. Other than that. Structures such as micropores, mesh covers, laminations, and sand filling are also explosion-proof forms of this principle. Explosion-proof electrical equipment used in underground coal mines must be more robust.
For the equipment of Class I mining face, the outer casing shall be made of steel plate or cast steel; the equipment of Class I non-mining working face shall be made of the shell of not less than HT25-47 gray cast iron; Class I portable equipment and For Class II equipment, the casing may be made of a light alloy having a tensile strength of not less than 117.6 N/mm2 (12 kg/mm2) and a magnesium content of not more than 0.5% by weight.
Increased safety structure of explosion-proof camera
Increased safety mechanisms are also widely used in explosion-proof electrical equipment, such as motors, transformers, lamps, and electrical equipment with inductive coils. It uses a series of safety measures on the equipment, such as the use of high-quality insulation materials, lowering the temperature rise, increasing the clearance, improving the quality of the wire connection, etc., so as not to cause sparks, arcs or dangerous temperatures to the maximum extent. Or the use of effective protective components to produce sparks, arcs or temperatures that do not ignite explosive mixtures for explosion protection purposes.
There is also a non-sparking type similar to the increased safety type explosion-proof measures. It is an electrical device that does not generate sparks and dangerous high temperatures during normal operation, nor can it cause a detonation failure. Compared with the increased safety type, there is no provision for additional measures to improve the safety and reliability of the equipment. Therefore, the non-sparking type of safety is lower than the increased safety type and can only be used in the hazardous environment of Zone 2.
Positive pressure structure
The explosion-proof principle of the electrical equipment of this structure is to ensure that the internal protective gas pressure is higher than the surrounding to prevent the explosive mixture from entering the outer casing, or a sufficient amount of protective gas passes through the outer casing to lower the concentration of the internal explosive mixture below the lower explosion limit.
Under normal circumstances, there must be no ventilation angles inside the electrical equipment that affect safety. During normal operation, the air pressure or inflation pressure of the air outlet shall not be lower than a certain value, otherwise an alarm will be issued or the power will be cut off immediately. Sparks and arcs inside the equipment are not allowed to blow out from any gaps or at the outlet.
The positive pressure type structure is not related to the level of explosive substances in use, and is often used in equipment or large electrical equipment where internal components are easily damaged, or it is difficult to make electrical equipment in other explosion-proof structures with self-ignition points T4 and T5. on.
Sand-filled structure
The sand-filled structure is a powder material filled with sand or other specified characteristics in the outer casing so that under the specified conditions of use, the arc or high temperature generated in the casing cannot ignite the surrounding explosive gas environment.
When the medium used makes the granular solid (usually quartz sand) as the isolation medium, it is called the sand-filled electrical equipment; and the medium used as the solidified material filler (general epoxy resin), the ignition source is encapsulated in Inside the packing, when isolated from an explosive mixture outside, it is also called a potting type electrical equipment.
Intrinsically safe structure of explosion-proof cameras
The intrinsically safe structure is only suitable for weak current circuits, such as small electrical equipment such as test instruments and control devices. Either the spark or dangerous temperature generated under normal conditions or under abnormal conditions will not detonate the explosive material, thus making the explosion-proof structure with higher safety, in which the surface temperature of all components on the circuit or equipment must be less than the specified To prevent ignition caused by thermal effects.
The intrinsically safe explosion-proof electrical circuit must be isolated from other circuits to prevent electromagnetic or electrostatic induction of the hybrid line. In particular, wiring outside the structure must be carefully measured to ensure the explosion-proof performance of electrical equipment and wiring.
Explosion- proof oil-filled structure of explosion- proof camera
The explosion-proof and oil-filled structure is independent of the level of explosion in use and is suitable for small operation switches. The oil to be filled should have high chemical stability. In order to observe the height of the oil level, the equipment should be equipped with an oil level indicator or an oil level signal device.
Oil-immersed explosion-proof structure switches, controllers and other equipment, due to oil degradation or leakage, etc., equipment damage is difficult to repair, need special attention. In addition, the equipment can no longer be used when the explosion-proof performance is impaired due to the inclination or the shaking of the oil surface.
Explosion -proof structure of explosion- proof camera in explosive dust environment
Dust-proof electrical equipment is designed to limit the maximum surface temperature of the enclosure and to use a “dust-tight†or “dust-proof†enclosure to limit dust ingress to prevent ignition of flammable dust. This type of equipment installs live parts in a housing with certain protective capabilities, which limits the entry of dust and isolates the ignition source from dust to prevent explosions. The equipment is divided into Type A equipment or Type B equipment according to the difference in the dustproof structure of the equipment. According to the dustproof level of the equipment casing, the equipment is divided into 20, 21 and 22 grades, which are suitable for dust hazardous areas in Zone 20, 21 or 22 respectively.
Zhoushan Jinsheng Bimetallic Plastic Machinery Factory , https://www.jinshenggalloy.com