Order this information in Print

Order this information on CD-ROM

Download in PDF Format

     

Click here to make tpub.com your Home Page

Page Title: SECTION III TECHNICAL PRINCIPLES OF OPERATION
Back | Up | Next

Click here for a printable version

Google


Web
www.tpub.com

Home


   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Combat
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
USMC
   
Products
  Educational CD-ROM's
Printed Manuals
Downloadable Books
   

 

TM 9-4120-389-14 SECTION III TECHNICAL PRINCIPLES OF OPERATION 1-10.  REFRIGERATION CYCLE. a.  Cooling cycle.  Unit operation with mode selector switch set on COOL and the temperature control thermostat set to DECREASE. Compressor (3) Figure 1-3 starts. The compressor (3) takes cold, low pressure refrigerant gas and compresses it to a high temperature, high pressure gas.  This gas flows to the condensor. coil (5) and receiver (8). The  condenser  fan  draws  outside  ambient  air  over  and  through  the  condenser  coil  (5).    The  high temperature, high pressure gas from the compressor (3) 's cooled by the flow of air and is changed into a high pressure liquid. The cooler, high pressure liquid refrigerant flows through the dehydrator (filter drier) (9) and removes any moisture (water vapor) or dirt that may be carried by the liquid refrigerant and to the sight glass (11), which indicates the presence of moisture and quantity of refrigerant in the system. The liquid line solenoid valve (10) is controlled by the temperature control thermostat on the control panel.    This  valve  will  shut  off  the  flow  of  refrigerant  to  the  evaporator  section  when  the  temperature  in  the conditioned area reaches the set point. The expansion valve (12) controls the amount of pressure of liquid refrigerant to the restrictor (13) and evaporator coil (14).  The expansion valve (12) senses the temperature and pressure of the frigerant as it leaves the evaporator coil.  By use of a sensing bulb and "external equalizer line" the valve constantly adjusts the flow of liquid refrigerant to the evaporator coil (14). As the liquid refrigerant leaves the expansion valve (12) it passes thru a restrictor (13) and enters the evaporator  coil  (14).    As  the  liquid  enters  the  coil  at  a  reduced  pressure,  the  reduction  in  pressure  and  the warmer air being forced across the tubes of the coil cause the refrigerant to boil and change to a as (vapor). The evaporator fan circulates the warm air from the conditioned space over and through the evaporator coil. Refrigerant absorbs heat when it changes from a liquid to a gas. As the air from the conditioned spaces comes in contact with the evaporator coil (14), the air is cooled. The low pressure refrigerant gas is then drawn back through the accumulate (1) to the compressor (3) and the cycle is repeated. b.  Bypass cycle. This unit has a bypass cycle which allows cooling operation at low cooling loads without cycling the compressor (3) on and off. In bypass, the refrigerant is piped from the discharge (high side) to the suction (low side) of the compressor, bypassing the evaporator coil (14). 1-8

Privacy Statement - Press Release - Copyright Information. - Contact Us - Support Integrated Publishing

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business