Discussion on lighting technology of clean workshop

The principles and methods of lighting design for clean workshops are expounded. In the lighting design process, the characteristics of the clean workshop should be combined with the reasonable selection of light sources and lamps to meet the requirements of illumination and lighting quality.

Clean workshop; lighting arrangement; lighting method; specification table 1 minimum illumination value on the working surface of the clean area without lighting window, minimum size d (mm) and location visual work classification brightness contrast illuminance (lx) level mixed lighting general lighting d ! 0. With the advent of the 21st century, clean technology has been widely used in pharmaceutical, electronics, food, precision instruments and other industries. As a marginal and comprehensive discipline, clean technology has attracted more and more attention from domestic and foreign technical experts, which puts higher requirements on the design of clean workshops. Here, the author clarifies some points about the design of the lighting in the clean room.

The lighting design of any building must first understand the characteristics of the building (including size, structure, building grade, decoration requirements, etc.) and the work, production conditions and lighting requirements. These are the illuminance standards, lighting methods, light sources and lamps. An important basis for selection and luminaire layout.

Lighting characteristics of clean workshops In clean workshops, there are often a large number of clean rooms or even clean areas in a windowless environment. They all require artificial lighting, even if the clean room is adjacent to the external wall and has a closed lighting exterior window. Since three shifts of continuous operation are conducive to maintaining and utilizing the purification environment, nighttime production must still rely entirely on artificial lighting, so artificial lighting is essential.

Light sources used in clean rooms require spectral distribution as close to sunlight as possible. However, other methods are needed to compensate for the lack of UV exposure in artificial lighting. From the perspective of purifying the air-conditioning environment, in order to stabilize the indoor airflow and reduce the cooling capacity, it is required to use a heat source as much as possible, and a gas source using a gas discharge is preferable. In a high-precision clean environment, in order to prevent local eddy currents and corresponding dust movements in order to prevent uneven heat distribution in the room, local illumination should also use less heat sources.

Regarding the illuminance standard, since the clean room has no window or is closed by a window, it may have a certain influence on the psychology and physiology of the person. Therefore, the illuminance standard of the clean room is increased by one level compared with the general workshop. China's "Clean Factory Design Code" stipulates the illuminance value on the working surface of the clean area without the lighting window, which should not be lower than the requirements in Table 1.

For general lighting in mixed lighting without clear window, the illuminance value should be determined according to the corresponding illuminance value of 101151 for each visual level, not less than 200lx. In the clean workshop, the spectral distribution of the light source is required to be close to sunlight, and the illumination is high. The heat generation is small, and the shape and structure of the lamp must be adapted to the characteristics of environmental purification. The thermoluminescent light source represented by incandescent lamps is difficult to meet the requirements in terms of luminous efficiency, heat generation and light color. Nowadays, a gas discharge light source represented by a fluorescent lamp is commonly used in a purification plant. The spectral curve of a fluorescent lamp, especially a fluorescent lamp with improved light color, is close to the spectral curve of natural light. Fluorescent lamps have high luminous efficiency, typically 34 times that of incandescent lamps. The clean house requires high illumination, and the number of lamps is often not limited due to the conditions of returning to the tuyere. Fluorescent lamps can better meet this requirement. In addition, it generates less heat and is beneficial to air conditioning. It is an ideal light source in China. The fluorescent lamps are mainly straight tube lamps, and the fluorescent tubes have higher luminous efficiency, longer life and more stable quality. Most of the self-ballasted fluorescent lamps have used rare earth trichromatic phosphors and electronic ballasts. Using rare earth trichromatic phosphors, the luminous efficiency is 151301 higher than that of ordinary fluorescent lamps, the light decay is smaller, the life is longer (up to 1200h), the color rendering index Ra is 85, and the mercury content is 801, which reduces the number of lamps in the clean room. The number of lamps, so it is widely used in clean workshops, especially for vertical laminar flow chambers where high-efficiency filters occupy a large area.

The arrangement of the luminaires Fluorescent luminaires can be divided into embedded and surface mounted according to different installation methods.

Although the technical interlayer on the upper part of the clean plant creates conditions for the embedded installation, the construction and maintenance are more complicated, and the construction lamp hole and the embedded lamp are not easy to form a gap. Surface mounted luminaires include both suspension and ceiling. Although the suspended luminaire itself is not a dust source, it is not good for indoor viewing and airflow organization. Therefore, the current "Clean Factory Design Code" stipulates that: the general lighting fixtures in Jijing are ceiling mounted. If the luminaire is embedded in the ceiling, the installation gap should have reliable sealing measures. At present, most clean workshops tend to use closed-cell ceiling fluorescent lamps, which require a streamlined cover that is not easy to accumulate, and can be opened for inspection from below, and the switch is set outdoors.

The lighting method in the clean room is based on the different illumination requirements of the production, the indoor building plan form, the layer height, the air flow and the technical interlayer. There are three types of lighting: the light strip, the scattered light and the light ceiling. Although the light-emitting ceiling can obtain uniform high illumination on the work surface, it often produces strong diffused light, which makes the parts lack the necessary shadow and three-dimensional sense, which is unfavorable for high-precision vision and therefore is not commonly used. Light-emitting strips and dispersion arrangements are more common, with the light-emitting strips being the most used.

The turbulent flow clean room ceiling area has a considerable amount of space, it is easy to arrange the lamps, and the horizontal laminar flow room is easier. The ceiling of the vertical laminar flow chamber is the most complicated. When the area of ​​the high-efficiency filter arranged in the ceiling reaches 60080 of the total area, the arrangement of the lamps will have a large conflict with the high-efficiency filter and the airflow stratosphere, which needs to be comprehensively solved.

In the case of low layer height, in order to obtain the laminar airflow on the working surface, the allowable interval width between the high-efficiency filters is very narrow, and it is often difficult to achieve high illumination requirements with general illumination, and mixed illumination is required. When the vertical laminar flow chamber area is small and the ceiling portion is inconvenient to set the luminaire, it may be considered to provide horizontal corner belt illumination along the top of the side wall.

(1) There is a turbulent clean room with a height of 5.5m and a ceiling height of 2.6m. The ceiling of the ceiling is provided with a ceiling-type fluorescent lamp belt and a static pressure box air supply plate. The four walls are decorated with light gray color steel plate. The light source is 2X36W. Fluorescent tubes, lamps are replaced from below the ceiling. At 220V, the average illuminance of 35 test points on the 0.75m elevation plane is 9001x, and the test points with illuminance above 7001x account for 800. As shown: there is a turbulent clean room with a height of 5.5 and a ceiling height of 2.7. ,. The ceiling is provided with a static pressure box orifice plate for air supply. The ceiling-mounted luminaires are arranged in a distributed manner, and the four walls are decorated with light gray color steel plates, and the light source is a 2X36W fluorescent tube. The average illuminance of the 0.75m working face is determined to be 3381x, the highest value is 4511x, and the lowest value is 2701x. The ceiling layout and plane measurement results are as shown, the illuminance uniformity reaches 0.8. From the first example, it can be seen that the illuminating lamp strip arrangement is compared. It is suitable for large areas where high illumination is required, but the clean room ceiling should have enough free space to ensure its installation. The second example shows that the dispersion arrangement is more suitable for applications where the illuminance requirements of the work surface are not too high, but require higher illumination uniformity. Different clean rooms should adopt different lighting methods, and at the same time, comprehensive consideration of the surrounding environmental factors can produce better lighting effects.

6 Emphasis on standby lighting and evacuation lighting The standby lighting should be set up in the clean room. The standby lighting should meet the minimum illumination of the necessary places and parts for the necessary activities and operations. Alternate lighting generally uses accident lighting with an inverter. It is usually powered by 220V AC. When the power is off, the inverter automatically turns on the accident power supply or the battery works, and the illumination lasts for more than 30 minutes.

At the same time, emergency lighting for evacuation should be provided in the clean room. Evacuation signs shall be set at the corners of the safety exits and evacuation passages in accordance with the current national standards. In order to avoid the blockage of smoke during the fire, the light is generally installed along the channel at a distance of 0.81m from the ground. In order to ensure the safety of firefighters, the lighting voltage is generally 36V. Emergency lighting along the passage, stairwell to outdoor safety exit, set aside every 15m, and attached to the corner of the corridor and the stairwell or outdoor exit Evacuation direction mark.

To sum up, the rationalization of lighting arrangements and lighting methods in clean workshops should first be carried out in accordance with the relevant national regulations, strictly enforced, and at the same time be adapted to local conditions, combined with the characteristics of buildings, and with the production process, HVAC and other majors. Unification and coordination, using advanced and scientific design methods, can adapt to the development direction of the newly developed clean factory.

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