LED explosion-proof lamps and lanterns design and manufacturing

Electrical equipment used in explosive environments is divided into Class I, Class II and Class III. Class II and Class III non-mining LED explosion-proof lamps are mainly used in industries where flammable and explosive gases or dusts exist, such as petroleum, petrochemicals, chemicals, pharmaceuticals and so on. According to the analysis of explosion-proof electrical equipment, the main use of explosion-proof, increased safety and composite type. At present, the explosion-proof type is the mainstream lighting fixtures. This paper analyzes the views and conclusions of the design and manufacturing process of explosion-proof LED explosion-proof lighting products.

I. LED performance characteristics

   First of all, energy saving.LED lamps and lanterns have low operating voltage under constant current drive. In the same lighting effect, power consumption is incandescent 1/10, fluorescent 1/2. Industrial environments often require long-term lighting, energy saving effect is more significant.

Secondly, environmental protection, LED is a durable light-emitting body, impact resistance, unbreakable, recyclable waste, no pollution. Light source is small, can be combined at will, is an easy to develop, easy to install and maintain compact lighting products. LED light source is currently more expensive than conventional light sources, but from the perspective of energy saving, with a year of energy saving to recover the investment in light sources, can produce energy saving net value of several times the profit.

Again, high luminous efficiency. LED after decades of development, luminous efficiency has improved greatly. Conventional light source luminous efficiency of 12-24 lm / W, fluorescent lamps 50-70 lm / W, sodium lamps 90-140 lm / W, most of the power consumption is heat loss. Improved LED luminous efficacy of 80-200 lm/W, good optical monochromaticity, narrow spectrum, can directly emit colored visible light without filtering.

Finally, long service life. The use of electronic light field radiation luminescence, filament luminescence is easy to burn, thermal evaporation, light attenuation, etc. LED lights are small, light weight, epoxy resin encapsulation, can withstand high-intensity mechanical shock and vibration, and is not easy to damage. The average life expectancy of 100,000 hours. the service life of LED lamps and lanterns can be up to 5 to 10 years, greatly reducing the maintenance cost of lamps and lanterns, to avoid the problem of frequent replacement of lamps and lanterns.

II. Explosion-proof LED explosion-proof lamp explosion-proof principle

   Explosion-proof LED explosion-proof lamp is the light source, power supply and other components that may ignite explosive gases are all enclosed in a shell, in the event of an explosion, the shell can withstand any joints or structural gaps through the shell into the shell of the explosive mixture within the internal explosion without damage, and will not cause the external formation of an explosive gas by a variety of gases to ignite the explosive gas environment, so as to achieve the purpose of explosion-proof. purpose.

III. Explosion-proof LED explosion-proof lamps and lanterns design and manufacture

3.1 product structure

    Lamp shell needs to be able to withstand the impact of the internal explosion, according to the combination of heat dissipation and cost-effective, the shell is usually made of light metal alloy (ZL102) castings, explosion-proof joints are often threaded, flat, cylindrical and other ways; explosion-proof surface roughness is not allowed to be greater than 6.3 μm, and the length of its explosion-proof joints and the size of the internal volume of the explosion-proof cavity and explosion-proof gap is closely related.

Explosion-proof lamps are usually composed of light source cavity, power supply cavity, wiring cavity.

    The light source cavity includes the shell, light source, transparent cover, reflector and so on. Light source cavity is the light part of the entire lamp, but also the key part of the heat generated, so the light source cavity in addition to a certain degree of strength, should also have a good heat dissipation function, so that the temperature of the lamps and lanterns to meet the requirements of the corresponding temperature group. Transparent cover is generally made of tempered glass, the more common way is to seal the transparent cover with epoxy resin in the light source cavity shell, and use the pressure ring fixed to achieve the effect of explosion-proof.

The power supply cavity includes the shell, driving power supply, and wiring terminals.

Wiring cavity is the cavity of the lamps and lanterns and external interaction, its focus is on the design and use of the introduction device. Cable introduction device for the most commonly used in the introduction of explosion-proof lamps and lanterns, the most common is the use of sealing ring introduction and packing seal introduction. The introduction of the sealing form of the device needs to be matched with the sealing ring size of the cable, and with the compression screw fully compressed to ensure the explosion-proof performance of electrical equipment.

3.2 Power supply design

   According to the LED light source power supply, there are usually two solutions, a multi-group power supply to provide multiple constant current sources, each constant current source individually for each LED power supply, these combinations are flexible. The failure of one LED will not affect the work of other LEDs. The other, an all-in-one constant current power supply, lacks flexibility meaning that a failure of one LED will affect the operation of another. From a system point of view, based on the principles of reliability and analysis, a simple series-parallel connection between components is not recommended. Taking into account the impact of relevant factors, making full use of the components to fully improve the utilization of the entire light source is the primary consideration. Therefore, DC centralized power supply solutions based on multiple constant-current modes and high-voltage DC centralized power supply solutions have received widespread attention. DC centralized power supply is characterized by high system reliability, high efficiency and low cost. The systematic, modular and intelligent design greatly improves the system’s ease of use and maintainability, and significantly reduces the management and maintenance costs.

3.3 Light source design

   According to the classification of light-emitting materials, the light source is divided into two categories: solid-state light source and gas discharge light source. In recent years, with the rapid development of science and technology, semiconductor light-emitting diode (LED) development is rapid. LED light source is used in industrial and mining, schools, hospitals, roads and other indoor and outdoor lighting in various fields. In the analysis of the principle of light emission, gas discharge light source in the use of a variety of inert gases to regulate the light performance of the light source, such as luminous flux, color temperature, color rendering and so on. For light emitted from solid-state light sources, there is no need to adjust the relevant photoelectric parameters.The temperature of the LED light source must not exceed 80 ℃. As the temperature rises, the light output and life expectancy decreases.LED light output ratio indicates that the LED junction temperature at about 50 ℃, the relative light output ratio of the lamp is 100%.

   Currently more commonly used light source from the package: integrated COB, 2835, 3030, 3535, 5050, 5054, 7070, the use of small packages, first and then string, light source decentralized design, friendly interface, large heat dissipation area, heat distribution, will not be localized overheating, and effectively improve the life of the LED lamps and lanterns.

Explosion-proof LED explosion-proof lamps as a mainstream explosion-proof lamps and lanterns, in the explosion-proof field has been widely used. However, there are still many problems that need to be solved using new technologies. In addition, the use of explosion-proof LED explosion-proof lamps need to reduce costs, further optimize the heat dissipation method, choose a reasonable constant current drive power supply, which is the key to design a good explosion-proof LED explosion-proof lamp.