Charging system
Before any charging of the refrigerant enters the system, it must be carefully pressure-tested for leaks both the low and high side compressor. Anhydrous carbon dioxide, should be used for this and all joints and connections carefully examined soapy water used for bladder test. Watch the gauges will indicate if a serious leak is present. After that a small amount of refrigerant should be added to the system, and all of the joints, pipes and connections, switched from hallide torch. (This is the trace technique for the detection of leaks, if fluorinated hydrocarbons are used. Any escaping refrigerant reacts with the flame of a torch, to produce green color.)
The system is considered to be free from leakage if after it was left under the pressure within 24 hours, with no variation is observed in a vacuum gauge, due attention is paid to ambient temperature variations that will change the gauge readings.
When the system is free from leaks, it must be dehydrated. This is achieved with the help of an auxiliary vacuum pump (never refrigeration compressor itself)to completely remove the hard vacuum the entire system.
Dehydration can only be achieved if liquid water in the system is made to a boil, then the couple be written off. 20C vapour pressure-2.337 kPa absolute. That is, vacuum around 99 kPa. The application of external heat to the system can help achieve the required amount of dehydration.
After the above testing and dehydration procedures, support systems must be configured to operate. This refers to the associated air treatment and water supply of the plant, together with their automatic controls. Cannot charge and began to work in cooling system if not already done. For example, if cooling water circulation pump sufficient volumes of water through condenser refrigerant plant will fail constantly high pressure cut-out.
The system must be removed from the tank or drum of the refrigerant through the dryer. For any given system, if the design of a duty to be received, only one mass of the refrigerant is correct amount for his work between the design of condensation and evaporation pressure. For packaged enterprise of known size and performance measured mass of the refrigerant must provide the requested operation. However, to plant more individualised nature, inspection glass and sensor points can be used to advantage in estimating the charges.
The location of the charging point varies depending on the size and type of plant. Very small piston engines may not have a special point for charging; then it must be done through the sensor connect the suction valve. In this case, it is important that only the pair (i.e., without liquid) refrigerant charged. For large installations, the charging point or expansion valve and the evaporator or in liquid line or liquid receiver. In these cases, the fluid may be filed in...
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Refrigerants