College】 【weak filters and air conditioning unit heat exchanger fouling treatment Results dust.

<br> 1 Introduction <BR> <BR> air conditioning unit (also known as air-conditioning box) filter dust phenomenon occurs after the end, will result in increased air resistance, fan efficiency variation; the heat exchanger in the event of Results dust, Results .scale phenomenon, will lead to the increase of thermal resistance. .<BR> <BR> By dirt and corrosion for a long time could easily lead to deterioration of pipe pressure resistance, and even the phenomenon of system leakage; and sprinkler system, after scaling, often cause nozzle clogging, seriously affecting the water chamber .heat exchange efficiency. .In order to improve the efficiency of air conditioning systems, extending equipment life, design a simple device to do periodic maintenance of air conditioning equipment easy maintenance is possible and necessary. .The device we have increased only an additional purchase of a solution spray pump tanks or replace the ordinary acid pump, so the actual maintenance process is extremely economical. .<BR> <BR> 2 air conditioner filters frequently used form of <BR> <BR> 2.1 <BR> <BR> the early effect of the early effect of filter commonly used metal mesh filter, ceramic rings, glass, coarse .polyurethane foam or a variety of man-made fibers as a filter layer, coupled with the network and the fixed framework of the composition of the filter. .In recent years, non-woven fabrics are being developed and utilized. .The filters are subject to manual cleaning and replacement, cleaning the filter in order to reduce workload and improve operating efficiency, you can drive around using paper filter. .This filter is mainly made of metal mesh (cloth) filter and filter volumes. .Filters in the transmission mechanism driven by a slow rotation, sticky self-cleansing in the oil bath, and continuous work. .<BR> <BR> 2.2 <BR> <BR> in effect filter that filters generally use a diameter of about lOp. .m around the glass fiber, the pore polyethylene foam or acrylic, polypropylene, polyester, etc. made for the media filter. .In different thickness and filtration rate, filter, will get a different filter effects. .In order to improve filtration efficiency, and enhance the air flow, drawer or bag often made of filter elements. .At present, the filter efficiency has been gradually by chemical fiber filter, this filter is made of felt-like, fiber density along the thickness direction of the different media, from coarse to fine. .Under the same conditions, the chemical fiber filter or glass fiber filter with the foam compared with high efficiency, small resistance. .Dust holding capacity and so on. .<BR> <BR> 2.3 <BR> <BR> HEPA filters mainly used for clean and efficient air-conditioning system requirements, for use as a final filter, which should be set before the beginning, intermediate, pre-filter. .This filter media is fine cotton, fine wool and so on. .These filter fiber diameter generally less than 1m, filter sheet made of paper. .In order to reduce flow resistance and increase the spread of dust effects, the low filtration rate (such as 2.0 ~ 2.5cm / s). .To this end the paper folded many times. .Ventilated area to filter area of 50 to 60 times. .This filter filter paper folded in the middle of the channel separated by corrugated sheet separation. .High efficiency filter can be used for non-toxic biological clean room requirements, to achieve an effective air capture bacteria particles. .<BR> <BR> 3 Results dust, scale and causes harm <BR> <BR> requirements in addition to clean air conditioning system, the general comfort of air conditioning units often use coarse filter. .In the course of the dust particles in the air adsorbed on the filter, and inevitably led to filter clogging, increased resistance to airflow, the efficiency of the fan, it will cause serious fan pressure head is insufficient to meet air requirements, so .filters should be cleaned regularly to meet the air conditioning unit operating conditions. .<BR> <BR> But in actual use of the process. .Neglected part of the construction unit and easy maintenance problems, and operators in maintenance and management of air conditioning units, they only consider how to facilitate and extend the air conditioning units in the single run time. .Sometimes even coarse filter removed. .This unit operation after a certain time, dust in the air conditioning unit on the adsorption between the heat exchanger fins, which led to decreased heat exchange efficiency, air supply plummeted. .In addition, because of dust in the fins on the bond, condensation water can not work towards the development of bead-like condensation dripping water tray can not be successful, this will increase the thermal resistance. .<BR> <BR> Dual hot and cold heat exchanger surface. .Using hot water or steam heating medium to the internal scaling is inevitable in the pipeline (mostly scale). .Steel wall of the heat exchanger larger thermal conductivity λ (λ ≌ 50w / m · k), while the small scale of the thermal conductivity λ (λ = 1.2 ~ 1.4W / m · k), only the former 2 .. 4 ~ 2.8%. .This results in increased thermal resistance of heat exchanger, so that the effect of decreased air conditioning units. .On the washer, the knot dust, scaling also has a serious impact. .We can affect the spray chamber from the following factors to heat exchange efficiency analysis: <BR> <BR> (1) the quality of the air flow rate of up (u is air velocity, m / s; p is the air density, kg / m) .. .When the filter or heat exchanger fins is blocked, through air conditioning units to reduce the air mass flow, air flow rate decreased. .Experiments show that the reduction due to air mass flow and air flow rate decreased, the heat exchange efficiency washer worse. .<BR> <BR> (2) water coefficient μ. . Coefficient of water is used for treatment ofair per kg of water. .If the air flow through the washer for the G (kg / la), the total water volume W (kg / h), the water coefficient μ is expressed as: <BR> <BR> thinner when the system pipe scale, nozzle clogging ., which led to the decline in water content lead to reduced water coefficient. .Practice has proved that water coefficient within a certain range will cause spray chamber to reduce heat exchange efficiency decreased. .<BR> <BR> (3) spray chamber characteristics. .Washer nozzle mainly refers to the structural characteristics of the form of aperture, the nozzle arrangement density, rows, pipe spacing, water spray chamber direction and the cross-section dimensions. .Experiments show that, other things being equal, small diameter nozzles spray droplets are small, increasing the contact area with air, so a good heat exchange efficiency. .However, the smaller the nozzle diameter, the more likely to cause nozzle clogging, but once the cause scaling of the nozzle clogging, can not be guaranteed to meet the design requirements, advantages and is not reflected in the. .<BR> <BR> 4 Results dust, scaling approach <BR> <BR> 4.1 <BR> <BR> processing filters filter the air conditioning unit basically using removable, so cleaning .or replacement are more convenient, general wash-water can be used. .However, oil-use environment such as the existence of dust, washing with water is often not very effective, when required CHANGSHA COMMUNICATIONS (a washing liquid) to deal with. .The specific method is: the Muddy Remove dust filter soaked with water after thoroughly dry water. .And then evenly pour the right amount of liquid (or spray) in the filter, so that the liquid penetration of their own 3 to 5 minutes. .Finally, rinse with water until all dirt is removed to resume normal operation. .<BR> <BR> 4.2 Treatment of water pipes and nozzles <BR> <BR> we can washer system, the highest point and lowest point of an inlet valves were set, and a drain valve. .Set in the air conditioning unit at the top of a solution tank. .Operation, first turn off the spray pump before the valve, open the drain valve to release water to make water pipes and the nozzle closed. .The preparation of a good scale scavenger (such as the gram scale) from the solution tank full of piping through the inlet valve. .When you reach the scheduled time (usually 3 to 4 hours), open the drain valve will be excluded liquid, and finally then washed with water 2 or 3 times to Sin. .If the acid used in jet pump is the pump (you can also install other acid pump), we can set up a water pump backward solution preparation tank and connecting pipes to form a loop. .Use of water through the first water drain valve plate removed, and then into the preparation of a good scavenger scale circulation tank, start the jet pump forced circulation 1 to 2 hours, and finally with water circulation 2 to 3 times. .<BR> <BR> 4.3 <BR> <BR> heat treatment of the surface heat exchanger fin to make full and liquid contact with the surface of the heat exchanger loop spray drying should be adopted, and its internal use .forced circulation. .Composed of two cycles can use the same tank, flow through the respective valve adjustment. .Liquid nozzle rows according to the size of the heat exchanger frontal area and a single nozzle spray drying area to determine other parameters such as the pump head, flow, pressure spray nozzle, diameter, etc. can be spray nozzle performance charts from the convenience check .too. .Specific operation, the first surface fin heat exchanger with water spray, to be fully wet fin surface dust has not dripping, it begins to spray drying liquid, liquid and fin full access to 10 to 15 minutes, with water .thoroughly wash-it. .<BR> <BR> 5 Conclusion <BR> <BR> 5.1 for cleaning and cleaning of equipment and piping installation should be considered in advance, If you have not considered the specific operation in the temporary installation, .After operating the equipment and pipelines do not have to remove, re-use until the next operation. .<BR> <BR> 5.2 after cleaning and cleaning operations, be sure to rinse to prevent the residual liquid corrosive liquid. .<BR> <BR> 5.3 Maintenance of air conditioning units generally opt for the Spring and Autumn seasons. .Through this method on a regular basis in the economic, effective conservation, we can ensure the unit's heat and moisture exchange efficiency and fan pressure head and purification requirements while extending the life of the unit to improve the economic efficiency of enterprises. .<BR> <BR>.