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    질문 Is there a problem in efficiency of the dryer under overcooling in the condenser?

    There may be a problem.


    The role of the condenser in refrigerated air dryer is to discharge heat absorbed by refrigerant through the condenser into the air (air cooling type) or cooling water (water cooling type), maintaining balance of the refrigeration system.


    However, overcooling in the condenser means that the refrigerant is discharging more heat than it absorbed. This implies imbalance of the refrigeration system and can therefore be problematic.


    Also, there had been occasional reports from installation sites on troubles caused by suction of liquid refrigerant by the compressor from excessive overcooling.

    질문 Is the after cooler essential part at the front end of refrigerated air dryer?

    It is economically feasible to install an after cooler at the front end of desiccant and refrigerated air dryers.


    Since heat load and moisture load of compressed air are proportional to temperature, reducing temperature of compressed air at the front end of the air dryer using low-priced after cooler can greatly reduce size of the air dryer at the rear end.


    This is the reason why front end after cooler is economically feasible. However, a separator and drain valve that perform definite functions need to be installed on the back of the after cooler. For your reference, after cooler is classified as air dryer with high dew point.

    질문 I am using two air dryers with the same capacity, and one has hot refrigerated compressor and the ot

    There is a problem in the air dryer with hot refrigerated compressor.


    Please check the following matters.


    1) If the two air dryers are installed in parallel, incorrect air pipe composition (especially with selection of the header) can result in leaning of air flow to one of the dryers. This dryer will be overloaded and its refrigerated compressor becomes hot.


    2) If the two air dryers are installed in series, refrigerated compressor of the front end dryer may become hot.

    Except in special cases, it is desirable to avoid serial composition.


    3) If the two air dryers are independently installed, compare capacity of the connected air compressor, pressure, temperature at the dryer entrance and surrounding temperature with rated conditions of the air dryer.

    When the operating conditions do not deviate from rated conditions, you must contact the place of purchase for service since there is a problem in the refrigeration system.

    질문 Can moisture inside compressed air at the site be completely removed by installing a filter?

    It cannot be removed.


    There are three types of moisture.


    In other words, it is classified into bulk liquid (condensed moisture affected by gravity), aerosol (condensed moisture particle with extremely small particle unaffected by gravity) and vapor (vapor in gas state). Only bulk liquid and aerosol can be removed using filter.


    Moisture in vapor state cannot be removed because it exists in molecular state.

    On one hand, the type of moisture that causes problems at the site is vapor, and mechanisms for removal of vapor include heat transfer and mass transfer. These are the very mechanisms of the air dryer.


    Therefore, only the air dryer can remove moisture in vapor state. Accordingly, installation of filters (particle filter and sealing filter) without an air dryer only removes a portion of moisture and can never completely remove moisture.

    질문 Why should refrigerated air dryer be continuously operated, unlike a refrigerator that can be starte

    It is desirable to continue operating refrigerated air dryer.


    Since refrigerated air dryer is a device that dehumidifies compressed air, compressed air that passes through the air dryer moves at a very high velocity.


    Therefore, if the dryer is stopped when compressed air passes through the air dryer, large volume of compressed air will pass through without being dehumidified. Furthermore, the refrigeration system cannot instantly reduce temperature as soon as it is started. To put it in another way, some time is required for the refrigeration system to be stabilized.


    On one hand, a refrigerator has its refrigeration system refrigerate / freeze an enclosed space and does not have a drastic fluctuation in load as in air dryer.


    This is why we use compressor on/off control method, the most inexpensive method among refrigerated compressor capacity control methods.

    질문 Why is dew condensation formed on the pipeline at the rear end of small refrigerated air dryer?

    Since small refrigerated air dryer only has air-to-refrigerant heat exchanger and does not include precooler / reheater (air-to-air heat exchange), pipe temperature of compressed air dehumidified by small refrigerated air dryer is low.


    here, when temperature of pipe is lower than dew point of surrounding air, dew condensation is formed on the pipe. This is why dew condensation is commonly formed on the pipe during summer season, when atmospheric dew point is high.


    On the contrary, dew condensation is not formed on the pipe during winter season as atmospheric dew point is low.

    질문 Is it necessary to operate refrigerated air dryer during winter?

    It is better to operate the air dryer during winter.


    However, you must be careful to prevent freezing of condensate. Pressure dew point (PDP) of a high-performance refrigerated air dryer is 4~10°C under pressure of 7kgf/cm2G, and it is converted to atmospheric dew point (ADP) of -21~-17°C.


    Meanwhile, ADP is low during winter because atmosphere is dry. On an extremely dry day with ADP of -21°C or below, there is no need to operate the refrigerated air dryer.


    The situation changes when operating pressure exceeds 7kgf/cm2G. For reference, there are not very many winter days with dew point of -21°C or below in Korea.

    질문 How are SCFM and CFM different?

    CFM and SCFM are units of volume flow rate.


    CFM stands for cubic feet per minute or ft3/min, and SCFM stands for standard cubic feet per minute.

    Therefore, these are units of flow used in the United States, a country that uses feet-pound unit system. CFM is a unit of air flow in ambient temperature, pressure, relative humidity and density. For examine, it is used as a unit of fan flow in an air-cooled condenser.


    SCFM is a unit of flow used in the field of compressed air. This unit is used to indicate flow of air dryer and air filter since flow of an air compressor is indicated as standard air.

    Standard air of pneumatic fluid power industry defined in ANSI/B93.45M is an air with temperature of 68°F (20°C), pressure of 14.7lb/in2 (1.01 bar) and relative humidity of 36% (0.0750 lb/ft3). Standard air temperature in gas industry is 60°F (15.6°C).

    질문 Reverse phase or reverse rotation of motor occurs

    (1) Kyungwon screw compressor
    0080 alarm occurs in the controller and it cannot be started. Check whether the reverse phase relay lamp inside the control box is turned on. If this lamp is turned off, switch the two main power cables after removing power supply.


    (2) Kyungwon scroll compressor
    Scroll compressor creates noise. In this case, immediately stop the compressor and switch the two main power cables after removing power supply.


    (3) Kyungwon reciprocating compressor
    Check the rotating direction attached to belt cover after power input. Since there is a serious problem in cooling when operated in reverse direction, stop the compressor and switch the two main power cables after removing power supply.

    질문 Can I remotely run load / no-load operation?

    Remote load / no-load operation is effective when load / no-load operation is to be simultaneously carried out on multiple compressors. Multiple compressors can undergo same operation using common contact point of pressure switch.


    This is a matter that requires internal wiring connection.
    Please contact our headquarters or agency for details.