explosion-proof light fixtures are mainly used in dangerous and harsh environments with flammable gas and dust. Since the lamps themselves are electrical products that convert electrical energy into light energy, when encountering overload conditions such as short circuits, electricity may generate flammable gases that can ignite and detonate. The high temperature of dust and electric spark, so "explosion-proof" means that it can only prevent the high temperature generated by the lamp itself or the electric spark under the action of oxygen in the air, igniting the combustible gas, dust and oxygen in the air and causing an explosion accident, and May prevent explosion caused by equipment or factors other than the luminaire itself.
Generally speaking, explosion-proof light fixtures mainly realize explosion-proof through the working principles of flameproof Flame Proof and increased safety.
A. The working principle of flame-proof explosion-proof light fixtures
Flame proof lighting allows explosions inside the lamp. At the same time, the working principle is to physically isolate the parts that generate high temperature and electric sparks in a flameproof enclosure. Flame proof lighting is to prevent the explosion inside the lamp from spreading to the lamp. External to achieve the principle of explosion-proof protection.
When the explosive gas mixture penetrates into the flameproof casing of the lamp and is ignited and an internal explosion of the lamp occurs, because the flameproof casing of the lamp can withstand the internal explosion pressure, the flameproof casing of the lamp can resist the pressure and explosives generated by the internal explosive gas. In the flameproof shell, the thermal energy generated by the explosion can be transmitted to the external environment of the lamp through the flameproof path designed in advance. When the thermal energy is transmitted to the external environment of the lamp, the thermal energy is not enough to detonate the external environment, so as to achieve the purpose of explosion-proof. , Explosion-proof type is the most common type of explosion-proof type, referred to as "Ex d".
The exterior of explosion-proof type of explosion-proof light fixtures is usually constructed of metal materials, so that the lamps have a very good performance in terms of heat dissipation, shell strength and durability. Moreover, common parts (lamp sockets, interlocking lights, etc.) will adopt explosion-proof structure design.
B. Working principle of increased safety explosion-proof light fixtures
The increased safety explosion-proof light fixtures do not allow explosions inside the lamps. At the same time, the working principle is that after taking enhanced safety measures for parts that may generate high temperature or electric sparks, it is not enough to cause internal explosions in the lamps. Explosion to achieve the principle of explosion-proof.
When the explosive gas mixture intrudes into the safety-enhancing shell of the lamp, since the components are made of materials with better insulation properties, the creepage distance in the shell is optimized in advance, and when the circuit fails, it will basically not cause high temperature or electric sparks. Therefore, it is impossible to ignite the combustible gas and dust inside the lamp housing. Of course, it is impossible to cause an explosion of the surrounding environment outside the lamp housing, so as to achieve the purpose of explosion-proof. The increased safety type is also the most common type of explosion-proof type, referred to as "Ex e".
explosion-proof light fixtures and lampshades have the function of automatic power off when they are opened, but because the interlocking design is more troublesome, most lamps are not set up. Usually, warning messages such as "It is strictly forbidden to open with electricity" are set in the obvious parts of the shell.
Try not to open the protective lampshade when the explosion-proof light fixture is just powered off, because the surface of the bulb still has a high temperature after the power is turned off. At this time, opening the explosion-proof light fixtureshade rashly will still have the possibility of igniting the explosive gas mixture, so when we use some surfaces with When the light bulb is at a high temperature, you should pay attention to this problem when you open the protective cover.
When replacing lamps or bulbs, care should be taken to protect the flameproof joint surface of explosion-proof light fixtures, and not be easily damaged; after cleaning, the flameproof surface should be treated with anti-rust and anti-corrosion (coating with phosphating paste or 204-1 anti-rust oil). ), can not be easily treated with other paints; the rust layer should not appear on the explosion-proof surface. If there is slight rust, the corresponding treatment should be made in time.
It is very important for explosion-proof light fixtures to use dust-proof and waterproof sealing rings and ensure that the surface is intact. If the sealing ring used for protection is broken or lost and other conditions, spare parts of the same specification and material should be selected for replacement. At the same time, during the replacement process, attention should be paid to check whether there is any abnormality inside the lampshade. If there is cracking or corrosion, it should be replaced replace.
explosion-proof light fixtures should be regularly maintained and repaired in time during use.
1. The maintenance and repair personnel of explosion-proof light fixtures need to undergo on-the-job training to understand the performance of explosion-proof light fixtures and clarify the use requirements. Maintenance personnel must have professional knowledge and be familiar with the product structure of explosion-proof light fixtures.
2. Regularly remove dust and dirt on the shell of explosion-proof light fixtures, and improve the light efficiency and heat dissipation performance of explosion-proof light fixtures. The cleaning method can be based on the protection capability of the explosion-proof light fixture housing, using water spray (marked on the lamp above IP65) or wiping with a damp cloth. When cleaning with water spray, the power supply should be cut off, and it is strictly forbidden to wipe the plastic casing (transparent part) of the explosion-proof light fixture with a dry cloth to prevent the generation of static electricity.
3. Check whether the plastic shell (transparent part) of the explosion-proof light fixture has serious discoloration. If the discoloration is serious, it means that the plastic has been aged. Check whether the transparent parts have been impacted by foreign objects, and whether the protective net is loose, desoldered, corroded, etc. If so, stop using it and repair and replace it in time.
4. If the light source of explosion-proof light fixtures is damaged, the light should be turned off in time, and the replacement should be notified to avoid long-term abnormal state of electrical components such as ballasts due to the inability of the light source to start.
5. If there is accumulated water in the lamp cavity of explosion-proof light fixtures and lanterns used in humid environments, it should be removed in time, and the sealing parts should be replaced to ensure the protective performance of the shell.
6. When opening the lampshade of explosion-proof light fixtures, the cover should be opened after the power supply is cut off according to the requirements of the warning sign.
7. After the explosion-proof light fixture is opened, check whether the explosion-proof joint surface is in good condition, whether the rubber seal becomes hard or sticky, whether the wire insulation layer is green and carbonized, and whether the insulating parts and electrical components have deformation and scorch marks. If these problems are found, they should be repaired and replaced in time.
8. The model, specification, size and performance of the light source, parts and electrical components after repair and replacement of explosion-proof light fixtures should be exactly the same as the light source, parts and electrical components before the repair and replacement.
9. Before closing the cover, use a damp cloth (not excessively wet) to wipe the back light and transparent parts of explosion-proof light fixtures lightly to improve the light efficiency of explosion-proof light fixtures. A thin layer of 204-1 replacement type anti-rust oil should be applied on the flameproof joint surface, and attention should be paid to whether the sealing ring plays a sealing role in the original position when closing the cover.
10. The sealed part of explosion-proof light fixtures should not be disassembled and opened frequently.
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