Seven key issues of purification engineering design and construction:
1. Air duct requires both economy and efficiency
In the centralized or purified air conditioning system, the requirement of air duct is to supply air economically and effectively. The former requires low price, convenient construction, low operation cost and small resistance to internal surface smoothness. The latter refers to good tightness, no air leakage, no dust generation, no dust accumulation, no pollution, fire resistance, corrosion resistance and moisture resistance.
In operation, sometimes the local resistance of pipe fittings is much higher than the resistance along the air duct, which needs to be improved. Pipe fittings mainly include elbow, reducer tee and four-way pipe. The radius of curvature at the center of the bend shall be greater than the side length of the rectangular air duct, and the diameter of the circle shall be 1.25 times. Large section air duct shall be equipped with deflector in the pipe to reduce resistance. In the actual installation and construction, less such treatment. For reducer, it is not allowed to change the diameter suddenly. It is better to be a gradually expanding (shrinking) pipe. The expansion angle of each side of the gradually expanding pipe shall be greater than 15 °, and the contraction angle of each side of the gradually shrinking pipe shall be less than 30 °. The tee of the rectangular air duct shall be bent and divided along the air flow elbow, and the branch pipe shall also have a certain curvature radius. In case of 90 ° angle diversion, a deflector shall be added in the elbow.
2. Energy saving in air conditioning purification
Air conditioning purification is a large energy consumption, so energy saving measures should be paid attention to in design and construction. In the design, the division of system and area, the calculation of air supply volume, the determination of temperature and relative temperature, the determination of cleanliness level and air change frequency, the ratio of fresh air, the heat preservation of air duct, the influence of the bite form in the production of air duct on the air leakage rate, the influence of the connection angle of main pipe and branch pipe on the air flow resistance, whether the flange connection is air leakage, etc., and the selection of air conditioning box, fan, water chiller and other equipment are none One is not related to energy consumption, so these details must be taken into account.
3. Select air conditioning box according to climate conditions
As for the selection of air conditioning box, the climate environment should be considered. For example, in the north area with low temperature and large dust content in winter, the new air preheating section shall be added to the general air conditioning unit, and the water spraying air treatment mode shall be adopted, so that it can not only wash the air dust, but also generate the heat exchange to meet the required temperature and humidity. In the south of China, where the climate is humid and the dust concentration in the air is low, there is no need to preheat the fresh air in winter. The primary filter is used to filter the air and adjust the temperature and humidity. The surface cooling surface regulates the temperature and humidity. It can also strengthen the temperature and humidity reduction process, and then through the intermediate filter and terminal high-efficiency or sub high-efficiency filter. The air conditioning box is equipped with variable frequency fan, which can not only save energy, but also flexibly adjust the air volume and pressure.
4. Telephone and fire alarm equipment are indispensable
The clean workshop is equipped with telephone and intercom telephone, which can reduce people's walking in the clean area, reduce the amount of dust generation, and timely contact with the outside in case of fire, and create conditions for normal working contact. In addition, a fire alarm system shall be set up to prevent the fire from being easily found outside and causing significant economic losses.
5. Multiple chillers are more flexible
If the cooling capacity of the chiller is required to be large, it is not suitable to select a single machine, it is better to use multiple mechanisms, and the motor is better to use frequency conversion speed regulation to reduce the starting power. Multiple machines can be used flexibly, so as not to waste energy.
6. Automatic control device ensures full adjustment
At present, some manufacturers use the manual way to control the air volume and air pressure, but because the regulating valves controlling the air volume and air pressure are in the technical compartment, and the ceiling is also the soft ceiling of color steel plate, which is basically adjusted during the installation and commissioning. Since then, most of them have not been adjusted, and in fact, they cannot be adjusted.