Page 88 - The Veterinary Laboratory and Field Manual 3rd Edition

The selection, use, maintenance and quality control of laboratory equipment and supplies 57

dIGItaL car rEFrIGEratorS • Defrost and clean refrigerators regularly.
Digital car refrigerators run on electricity. Either • Do not use a knife or metal to remove ice
a 12 V source, if plugged in to a motorbike or formation in the freezing compartment.
car, or 220 V if plugged in to a mains supply. • Use a voltage stabilizer of at least 4 amps.
Smaller size cool boxes can be used on a motor- • Do not place hot material inside the refrig-
bike while the larger (Figure 2.16) ones can be erator.
used in a car. 3 • Never overload a refrigerator, the air inside
The more sophisticated car refrigerators can the refrigerator must be able to move freely,
be adjusted to 37°C. In a cold climate, these cool otherwise the cooling capacity is not optimal.
box/incubators can be used to store whole blood Therefore, never put items against the back
samples (the clotting of blood is a biological wall of the refrigerator.
process that needs at least room temperature) • Make sure that the refrigerator ventilation
otherwise the serum-production will be very grill is not blocked or obstructed.
poor if the whole blood samples are kept at 4°C. • Check the amount of ice forming around the
freezer compartment.

For solar-powered cooling equipment the fol-
lowing are also relevant.

• Check the indicator lights and any other
meters.
• Clean the solar panel.
• Check for shadowing of the solar panel.
• If the batteries are of the sealed type, no
maintenance is needed, if open (non-sealed)
batteries are used, the level of the electrolyte
(acid mixture) in any of the cells in the bat-
Figure 2.16 Digital cool box, larger size, can be used teries has to be checked and filled up with
in cars. Photo: Dometic company. distilled water if the level has dropped.

Care and maintenance Quality assurance

Bear in mind the following when maintaining • Check daily the inside minimum and maxi-
cooling equipment. mum temperature of the refrigerators/freezers
(at the same time each day, for example, in
• If parts need to be replaced try to ensure the morning when entering the laboratory)
that the correct specifications are met before (use the form ‘FORM-SOP-LABORATORY-
installation. EQUIP-05–01 Temperature registration min
• While transporting, keep refrigerators in an max thermometer’).
upright position if possible. • Keep the temperature probe in a small 100 ml
• Wait 24 h before switching on the refrigerator plastic bottle filled with water and covered
after transportation. with a lid. This will avoid measuring tem-
• Do not place the refrigerator with its backside perature fluctuations when opening the
against the wall. Keep a gap of at least 10 cm. refrigerator.

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