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  • HUMIDIFICATION - 3

    humidification spinning mill
  • FANS:

    In any air handling system the fan is a key conponent. It is a device which moves the air. This is achieved
    by pressurising the air, the resultant pressure difference makes the air to move. Fans can be classifed as follows

    1. Classification by air movement-1. centrifugal fan 2. Axial flow fan
    2. Classification by housing design -1. Scroll fans 2. Tubular fans
    3. Classification by pressure range- 1. high pressure 2. medium pressure and 3. low pressure
    4. Classification by Blade configuration - 1.forward curved blades 2.backward curved blades

     

    From the fan laws the following relationship can be arrived

  • CFM is directly proportional to fan RPM
  • Pressure is directly proportional to sqaure of RPM
  • Shaft power is directly proportional to cube of RPM

    AIR WASHER:

    Basic factors that determine the size of air washer are

  • Velocity of air through the washer
  • Type of nozzle used
  • Water quantity in circulation
  • No.of spray banks

    The main components in an Air washer are

  • Distribution plates
  • Distribution Louvers
  • Water pipes
  • discharge headers
  • stand pipes
  • nozzles
  • Eliminators

    REFRIGERATION:
    Air conditioning is a process to remove the heat from the place to be conditioned and reject the heat to
    a place where it is not objectionable. In other words, a heat pump is required to accomplish the same. The
    heat pump is called the refrigeration machine.

    There are three types of refrigeration machines classified according to their type of operation. They are

    1. vapour compression system
    2. absorption system
    3. vacuum

    Majority of the airconditioning systems used for commercial purposes work on vapour compression cycle.
    The main components used in the mechanical compression machines are

    1. compressor
    2. condenser
    3. metering device
    4. evaporator
    5. operating controls
    6. safety controls
    7. accessories

    THE COMPRESSOR:
    Under atmospheric temperature and pressure the refrigerant is in gaseous form. It is true that
    the cooling takes place when liquids evaporate to become gas. Therefore the gas refrigerant must be transformed
    into the liquid form. Most gasses can be made into the liquid form by raising its pressure (and cooling it,
    which is handled by the condenser). The equipment that increases the pressure of the gas by compressing it,
    is called the Compressor. Different types of compressors are

    1.Reciprocating 2.Centrifugal 3.Rotary and 4.screw

    THE CONDENSER:
    During compression however the refrigerant becomes hot. This is because of two reasons:

    1. Because of the work done on it (remember how warm the hand pump became when pumping air into your bicycle tires?) and
    2. Because the refrigerant is converted from gas to liquid releasing its latent heat

    This heat has to be removed to enable the gas to condense into a liquid easily. The equipment that removes
    the heat is called the Condenser. Different types are

    1.Air cooled 2.water cooled and 3.evaporative condenser

    EVAPORATOR:
    The Evaporator ('Cooling Coil' to most of us): From the condenser we now have the liquid refrigerant ready to go to work. This refrigerant can remove heat when it starts evaporating. The liquid refrigerant from the condenser is injected through a metering device called the capillary or expansion valve into  the cooling coil which is a bundle of tubes.

    Inside the cooling coil the pressure is low, because of the metering/throttling device on one side and the compressor suction on the other side. In the low pressure, the liquid refrigerant Starts evaporating rapidly. While evaporating it needs sensible heat to transform itself from the liquid to the gas state. So it soaks up heat from the surrounding tubes, and from the air, with which the tubes are in contact.
    This is what causes the cooling.

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