Refrigerator



Definitions of Terms

A refrigerator is equipment used for the storage of samples and reagents at low temperatures. Refrigerators are manufactured in different sizes. Some refrigerators have attached freezing compartments

Refrigerator
A picture of  Refrigerator

Types of Refrigerators

The types of refrigerators are:-

  • Electrical Refrigerators
  • Battery operated Refrigerator (12 V)
  • Kerosene Refrigerator (not recommended, difficult to control temperature and maintenance).

Parts of Refrigerator

  • Compressor
  • Relay
  • Thermo cut off
  • Condenser unit
  • Door gasket
  • Door switch
  • Temperature gauges
  • Hinges

1. Compressor

Function

-Pump for circulating refrigerant in the refrigeration cycle

2. Relay

Function

-Switches compressor ON/OFF

3. Thermo cut off

Function

-Compressor protection device against overheating

4. Condenser unit

Function

-Gas cooling device

5. Door gasket

Function

-Seal the door to preserve coldness

6. Door switch

Function

-Switches light in the fridge when the fridge’s door is open

4. Condenser unit

Function

-Gas cooling device

5. Door gasket

Function

-Seal the door to preserve coldness

6. Door switch

Function

-Switches light in the fridge when the fridge’s door is open

 Principle of Refrigerator

A refrigerator is an equipment, which transfers heat from an area of low temperature to one of a high temperature. It consists of a compressor and liquid refrigerant. The compressor pumps the liquid refrigerant, which turns into gaseous and exchanges heat at the surrounding/compartment.

Care of Refrigerator

Adhere to Biosafety precautions on handling biological specimens, laboratory articles including but not limited to wearing of laboratory coats, gloves, and other protective gears:

  • Do not expose condenser to the sunlight
  • Do not use sharp tools for defrosting.
  • Do not install the refrigerator near the wall (leave about 20cm from the wall)
  • Use stabilizer to prevent damage due to voltage fluctuation.

Uses of Refrigeratory

  • Always follow the manufacturer’s instructions.
  • Place the refrigerator sufficiently far from the wall (a minimum of 20 cm) so that air can flow past the condenser at the back.
  • The refrigerator door must seal perfectly to prevent warm air from entering the cooling chamber.
  • Set the correct temperature (2 – 8oC) for the refrigerator.
  • The temperature must be checked twice daily and recorded on a temperature chart.
  • Open and close the door gently to avoid disturbing the contents and do not leave it open unnecessarily.
  • Do not open the door again immediately after closing. A negative pressure is created inside the refrigerator after closing, requiring force to open the door, which may break the handle. 
  • Categorize the different laboratory items and store them separately, e.g. blood, microbiology specimens, and test kits.
  • Reagent inside must be placed in good order to allow good circulation of air inside

Limitation of Refrigarator

  • Must be cleaned outside daily
  • Should be defrosted and cleaned inside thoroughly once a month 
  • Should be defrosted by switching the power off and leaving the door open overnight. Never use sharp instruments to remove ice.
  • The compartment  should be disinfected with 70% alcohol when there is any contamination 
  • Dirt or dust from the coils and condenser should be removed using a brush.
  • The refrigerator must be protected from low voltages using a cutout device, e.G. Sollatek fridge guard.
  • The temperature must be checked twice daily and recorded on the temperature log.
  • The gasket (rubber lining on the door) must be washed with soapy water.
  • The gasket must be replaced when torn. Check the gasket by darkening the room, then placing a flashlight (torch) inside the refrigerator and looking for light leaks around the perimeter.
  • If the refrigerator is faulty, a qualified Biomedical Engineer must be consulted.

Basic Troubleshooting

1. Problem

-The refrigerator is working but has no cooling.

Causes

-Door gasket

Corrective Action

-Replace if it is damaged

Call engineer/ technician

2. Problem

-The refrigerator is working but has no cooling.

Causes

-Gas leakage

Corrective Action

-Replace if it is damaged

Call engineer/ technician

 3. Problem

-The refrigerator is working but has no cooling.

Causes

-Compressor

Corrective Action

-Replace if it is damaged

-Call engineer/ technician

4. Problem

-The refrigerator is not working.

Causes

-No power

Corrective Action

-Switch ON / call engineer/technician