Application and maintenance of factory explosion-p

2022-06-10
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Application and maintenance of factory explosion-proof lamps

according to relevant data, 60% of explosion accidents caused by electrical equipment are caused by lighting lamps, and more than 80% of them are caused by portable lamps. Therefore, the use safety of explosion-proof lamps used in factories has a significant impact on the safe operation of production units in petrochemical enterprises

1 Classification and selection of explosion-proof lamps

explosion proof lamps are generally classified according to the selected light source, explosion-proof structure type and use mode. According to the light source classification, there are explosion-proof incandescent lamp, explosion-proof high-pressure mercury lamp, explosion-proof low-voltage fluorescent lamp, mixed light source lamp, etc; According to the explosion-proof structure type, there are explosion-proof lamps, increased safety lamps, composite lamps, etc; Classified according to the mode of use, there are fixed explosion-proof lamps and portable explosion-proof lamps

first, select the light source of explosion-proof lamps. Although incandescent lamps are still widely used, they are gradually replaced by other light sources due to their low luminous efficiency and short service life. Among them, single plug non starter fluorescent lamp, self ballasting high-pressure mercury lamp and high-pressure sodium lamp are widely used

single plug starter free fluorescent lamp is a cold cathode gas discharge lamp. The luminous principle is to use the discharge between electrodes to generate ultraviolet radiation of mercury atoms, so as to stimulate the fluorescent substances on the inner wall of the lamp tube to emit light. This kind of fluorescent lamp has high luminous efficiency (about three times that of incandescent lamp), long service life, no starter is required for starting (usually there is a conductive layer on the lamp wall, called the Glow layer, which is used to complete the glow of fluorescent lamp; when the lamp tube breaks, the Glow layer is also damaged, and the lamp goes out), and low cathode temperature (about 200 ℃), so it is a safe and practical light source, which is very suitable for making increased safety lighting lamps

self ballasted high-pressure mercury lamp is a hybrid light source lamp that uses high-pressure mercury vapor discharge and incandescent and fluorescent substances to emit light. It has the advantages of high brightness, simple structure and fast starting speed. It changes the disadvantage of adding ballast to the previous high-pressure mercury lamp, uses tungsten wire to limit the current, and improves the light color at the same time. The disadvantage is that the service life is shorter than that of ordinary fluorescent high-pressure mercury lamp. High pressure sodium lamp is a kind of high pressure sodium vapor discharge lamp, which has the advantages of high luminous efficiency, low power consumption, strong fog permeability, long service life and so on

single plug non starter fluorescent lamp and self ballasting high-pressure mercury lamp are mainly used in the production unit of the author. When the original fixed explosion-proof incandescent lamps meet the minimum distance between the bulb and the transparent cover specified in the regulations and are approved by relevant units, they use the original lamps to replace the incandescent bulbs with self ballasting high-pressure mercury bulbs. Although high-pressure sodium lamp has certain energy-saving effect, due to its poor color rendering, we generally do not use it in production devices, but only in road lighting. Sometimes, in order to improve the straight white light color emitted by high-pressure mercury lamp, some high-pressure sodium lamps can also be mixed in the production device. For places requiring high-intensity lighting with good color rendering (such as on-site maintenance of large unit equipment), explosion-proof projection lamps can be selected. The light source is generally metal halide lamps, and the rated power can reach more than 1000W

the explosion-proof structure type of explosion-proof lamps shall be determined according to the regional level and scope of explosive gas environment. For example, explosion-proof lamps must be used in zone 1; Fixed lamps in zone 2 can be explosion-proof and increased safety, and mobile lamps must be explosion-proof. The level or group of explosion-proof lamps selected shall not be lower than that of explosive mixture in explosive hazardous environment. At the same time, the impact of environment on explosion-proof lamps shall be considered, and the requirements of various environments such as ambient temperature, air humidity, corrosive or polluting substances shall be met. The protection grade and anti-corrosion grade of lamps shall be selected according to different environmental requirements. Especially when there is corrosive gas in explosive gas environment, it is very important to select lamps with corresponding anti-corrosion performance

previously, in petrochemical enterprises, explosion-proof lighting lamps were mainly used in explosion-proof places. With the wide application of increased safety electrical equipment in zone 2 explosion hazardous places, increased safety and composite lighting lamps are increasingly used with excellent performance price ratio and reliable quality. On the basis of certain explosion-proof performance, compared with explosion-proof lamps, increased safety lamps have the advantages of light weight, low price, convenient installation and maintenance, long service life and so on. The most common composite electrical equipment used in petrochemical enterprises is the increased safety and explosion-proof composite explosion-proof electrical equipment, which is generally composed of explosion-proof parts, increased safety wiring terminals and increased safety shell. It not only has the safety performance of explosion-proof type, but also has the advantages of increased safety type

2 maintenance and overhaul of explosion-proof lamps

before installation, the explosion-proof lamps shall be checked from the nameplate and product manual: explosion-proof type, category, level and group; Degree of protection of enclosure; Installation method and fastener requirements for installation. The installation of explosion-proof lamps shall ensure firm fixation, the fastening bolts shall not be replaced arbitrarily, and the spring washers shall be complete. The sealing ring for dust-proof and water-proof shall be placed as is during installation. At the cable inlet, the cable and sealing washer shall be closely matched, the cross section of the cable shall be circular, and the sheath surface shall be free of concave convex and other defects. The excess inlet shall be blocked according to the explosion-proof type, and the compression nut shall be tightened to seal the inlet

in daily maintenance, the following points should be noted:

the power supply of explosion-proof lamps and Lampshades should be cut off automatically before opening. However, due to the complexity of setting interlocking device, it is not easy to realize, Therefore, most lamps are only equipped with warning signs with the words "no live opening" at the obvious part of the shell. In addition, because the surface temperature of the bulb is still very high after power failure, if the lampshade is opened immediately, there is still a risk of igniting explosive gas mixture (mainly refers to flameproof structure) Therefore, attention should be paid to incandescent lamp, high-pressure mercury lamp and high-pressure sodium lamp, which are light sources with high surface temperature and can quickly open the cover. Cey-1 explosion-proof fluorescent lamp, which is widely used by the author's unit, has an interlocking mechanism for opening the cover and cutting off power, which provides convenience and safety guarantee for maintenance work. Since the fluorescent lamp is a cold light source lamp, there is no high surface temperature, the cover can be opened immediately after power failure

when replacing the bulb (tube), the flameproof joint surface of explosion-proof lamps shall be properly protected from damage; The cleaned flameproof surface shall be coated with phosphating paste or antirust oil, and other paints are strictly prohibited; There shall be no rust layer on the flameproof surface. If there is slight corrosion, there shall be no pitted surface after cleaning. The sealing ring used for dust prevention and waterproof must be intact, which is very important for increased safety lamps. If the sealing ring is seriously damaged, the sealing ring with the same specification, electronic universal testing machine operation scale and the same material shall be replaced, and the whole lamp shall be replaced if necessary. During maintenance, pay attention to whether the lampshade is intact. If it is broken, replace it immediately

portable lamps are divided into feed power supply and self-contained power supply. For lamps powered by power feed, rubber sheathed cable shall be used from explosion-proof junction box (box) or explosion-proof plug to lamps, and its grounding or neutral wire core shall be in the same sheath; The cables shall be YC and YCW heavy rubber sheathed cables with the minimum allowable cross section of the main core of 25 mm2. It should be emphasized here that the cables of portable lamps are not allowed to have intermediate joints. The author's unit once had such an accident: the ethylene delivery pump was repaired one night, and two temporary explosion-proof lights were connected, with the explosion-proof sign of diict4. When the fitter picked up the lamp and looked close to the pump body, he ignited the ethylene gas leaked from the pump body and burned one of them on the face. After inspection, the explosion-proof performance of the lamp is normal, and the problem lies in the cable of the lamp. Originally, there was a cable joint 1.5m away from the lamp, which was wound with insulating wrapping cloth. When connecting and leading the lamp cable, it was dragged on the ground to expose the cable core. When the fitter lifted the lamp to illuminate the pump body, the exposed cable core touched the channel steel of the equipment foundation, so it ignited the ethylene mixture to the ground. The accident exposed a loophole in our explosion-proof safety management. After the accident, we carefully inspected all portable lamps and their cables, and eliminated the hidden danger of similar accidents. This accident tells us that there must be no fluke in the safety management of electrical explosion-proof. We must do it in strict accordance with relevant regulations and requirements in order to be safe

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