• Categories:Industry News
• Author:Becky Su
• Origin:
• Time of issue:2023-05-27 11:08
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(Summary description)Compressed air for SMT SMT compressed air requirements: clean and dry Dust particles, oil and liquid water in the air can be removed by relying on high efficiency filters. Many users only install simple oil and water separators at the inlet end of their SMT equipment. These have a very low filtration efficiency (typically no higher than 90%) and do not provide the level of gas purification required for SMT equipment use. The principles used for gas and liquid filtration are completely different, as the behavioural patterns of particles in air and liquid are quite different. Liquid filtration is mainly based on "blocking", while air filtration has three different principles: one is "direct capture" of larger, heavier particles that move in a straight line; the second is "inertial collision", which is used to capture slightly smaller, lighter particles that change direction slightly with the air flow; and very small particles are filtered out due to "Brownian motion". Once the particles hit the fibres, they are held firmly in place due to van der Waals forces, electrostatic suction and vacuum suction. Filters with high efficiency should be made of filter materials with good performance (e.g. borosilicate fibres) to provide clean air. At present, there are many filters designed and manufactured according to different filtering principles, and the following principles should be followed in the selection: (1) the level of the filter should be selected according to the situation of the compressed air source and the requirements for the use of the production equipment (e.g. the requirements of the equipment for the quality of compressed air, the pressure and flow of gas, etc.); (2) the filters of different levels should be followed in order from the low level to the highest level when used in combination configuration, can not jump levels at will} (3) filter element working life should be as long as possible, filter element replacement and maintenance should be convenient and simple; (4) the pressure drop between the filter inlet and outlet should be as small as possible; (5) the design of the filter should meet the requirements of ** production. Now, having a filter is not enough because, the water vapour in the air cannot be removed using a conventional filter and must be removed using a special drier. At present, there is a wide range of drying equipment for compressed air. Although the traditional adsorption dryer is cheap, it is bulky, the adsorbent is easy to age, consumes a lot of energy, and the regeneration of the adsorbent is more troublesome to deal with, and the filtering effect on water vapour is poor. Refrigerated dryer is a kind of compressed air drying equipment which is widely used* and *economical. Compared with other drying equipment, it does not consume any desiccant during operation and has the characteristics of energy consumption* saving and simple operation and maintenance*. SMT production equipment is generally required to be used in the plant where air conditioning is installed. In the hot and humid season, due to the large temperature difference between inside and outside the plant, the humid air is pressed into the network system by the air compressor without adding drying, and a large amount of water will condense in the process of temperature drop, while the water vapour remaining in the compressed air will directly enter the production equipment and continue to precipitate water in the process of further cooling, causing equipment damage. It is therefore essential that the air is dried before it enters the air-conditioned plant to filter out the water vapour contained in the air.