Study On The Cleaning And Maintainess Technology Of Center Air Conditioner

In central air-conditioning system, water is a kind of good and cheap cooling medium. After water treatment dissolved materials, gases, suspended materials and colloid still remain in water. Due to the increase of water temperature, the change of water flow speed, water evaporation, the concentration of impure substance, the dust entering into cooling towers which expose to outdoor sunshine, rain and wind, the equipment structure and material, etc, problems such as sediment,system corrosion and rapid growth of microorganism will occur which leads to block up pipelines. This will threaten and even damage the safe and economical operation of central air-conditioning system. In order to solve the above problems, the water must be treated and the system periodically cleaned.Chemical cleaning is the only way to remove the scales in the system. But the cleaning is technologically and operationally so difficult that improper treatment or choice of inhibitor could cause serious corrosion. The article aimed at studying cleaning chemicals in the water system and cleaning technics. From experiments conclusions could be drawn that for the seriously scaled,corrosive and adheresive central air-conditioners, cleaning methods such as water washing—soft clay removing--infiltration activating--acid washing--water washing--passivation was chosen at normal temperature while for not so serious ones, water washing—acid washing—water washing—passivation was used. For the given water, cleaning formulas were as follows:2%～3% hydrochloric acid,0.3% inhibitor,0.5%～1.0% passivation liquid. In the process of cleaning, the corrosive rate of Cu pipelines and Carbonized steel pipelines met the demands of HG/T2387—92 standard. The inside walls were cleaned and smooth. Velums were also equably compact and integrated.After the treatment problems such as scales,corrosion and microorganism could be temporarily solved. But in the long run these problems always existed and affected the normal operation of cooling systems. So the following water treatment after cleaning was necessary. It was designed that circulating cooling water treatment wasn't to remove impure substance while inhibitor,inhibiting scaling agent germicide would be added to achieve stable water quality. The study investigated water treatment chemicals and operation conditions. Composite water treatment chemicals as the main medicament were used in the mew system which kept the advantages of single finishing agent. Dynamic simulant experiments showed that on the conditions of adding 6.0 mg/L composite water stabilizer to feed water (adjust feed water alkalinty to 1.55 mmol/L with 190.0 mg/L vitriol)and keeping concentrated rate at three times, annual dirt thermoresistance and corrosive rate of stainless steel and copper alloy indicators were lower than the standard value of《Industrial Circulating cooling Water Treatment Design Specifications》(GB50050-95). SS,COD,pH,NH₃-N,total Phosphor and Zn,Cu,Mn in circulating sewage water were much lower than the specific standard.