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
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.
-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
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