Laboratory Refrigerator is one of the most important equipment. Its function is to maintain, in a controlled environment (refrigerated space), various fluids and substances, so that they are kept in good condition the lower the temperature, the less chemical and biological activity. Achieving this requires that the interior temperature of the refrigerator be below the ambient temperature.
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- 1 Types of Laboratory Refrigerators
- 2 Operation and Operation
- 3 Maintenance of a Refrigerator
- 4 Sources
Types of Laboratory Refrigerators
Various kinds of refrigerators are used in the laboratory, which could be grouped within the following temperature ranges:
- Conservation Coolers – Works in the 0 ° C to 8 ° C range.
- Low temperaturerefrigerators : they work in the range of 0 ° C to -30 ° C.
- Ultra low temperature coolers: they work in the range of 0 ° C to -86 ° C.
Operation and Operation
For their operation, refrigerators require the following provisions:
1.Electrical power supply with a ground pole suitable for the voltage and frequency requirements of the equipment. In general, refrigerators, depending on their capacity, can be obtained in versions that operate with 115 V, 60 Hz; 208/230 V, 60 Hz. It must be foreseen that the electrical connections comply with the national or international electrical regulations used by the laboratory.
2.If more than one refrigerator is installed that depends on the same electrical circuit, it must be verified that the electrical power and the safety of the same are adequate to supply the power that the refrigerators demand.
3.Connect the refrigerator directly to the electrical outlet. Never install a refrigerator in an electrical outlet that is overloaded or has voltage deficiencies. If possible, avoid using electrical extensions. The electrical outlet should not be more than 2m from the selected place to install the refrigerator.
4.Install the refrigerator on a level surface, providing that there is a free space around the equipment. The refrigerators in the base have a leveling system that allows adjusting the small differences in level that the floor may have. It is customary to leave a free space of 15 cm on the sides, and at the back to facilitate ventilation of the condenser.
5.Avoid installing the refrigerator in direct sunlight or near heat sources such as radiators or heaters. Remember that the greater the temperature difference between the environment and the condenser , the heat transfer will be more efficient.
Operation of conservation coolers is generally very simple and is outlined below: 1.Connect the refrigerator power cord to a grounded electrical outlet capable of supplying the required voltage and power.
2.Turn on the ignition switch.
3.Select the temperature by turning the knob to the desired temperature.
4.Wait for the refrigerator to reach operating temperature, before storing any product.
5.Charge the refrigerator according to the capacity established by the manufacturer. 6. Distribute the loads evenly inside the refrigerator . The uniformity of the temperature depends on the free circulation of air inside the refrigerator.
7.Avoid opening the door for long periods of time, to avoid the entry of thermal energy and humidity – present in the air – into the refrigerated environment, since ice forms and increases the working time of the refrigeration system. Open only to place or remove stored items.
Refrigerators are equipment that in general are not very demanding from a maintenance perspective, although they are demanding in relation to the quality of electrical power systems. If they are connected to good quality electrical circuits and verified to have good ventilation around the equipment, they can work for years without demanding specialized technical services. The refrigeration circuit is factory sealed and does not have components that may require routine maintenance. The most common maintenance routines are described below.
Internal cleaning (Frequency: every 3 months)
1.Disconnect the power supply cable.
- Verify that the interior shelves of the refrigerator are clean. They are generally made of metal mesh, to which a coating is applied to prevent corrosion. To clean them, any material that could interfere with the cleaning work must be removed from the refrigerator. Move the empty shelves forward and remove them. Apply a mild detergent with a damp cloth, gently rub the upper and lower surfaces. Dry and relocate in the original position.
3.After the shelves are removed, clean the interior walls of the refrigerator, using a mild detergent. Dry before mounting the interior accessories.
Condenser cleaning (Frequency: every 6 months)
1.Disconnect the power supply cable .
2.Check the position where the condenser is installed. Manufacturers place it primarily at the bottom and at the rear of the computer. Some refrigerators have it installed on top.
3.Remove the protection grille and the condenser protection filter, (not all manufacturers provide a filter).
4.Remove dirt and dust deposited on the surface of the condenser. Use a vacuum cleaner equipped with a suction brush. Run the entire surface of the condenser to remove dirt or accumulated dust.
- Verify that both the surface of the tubes and the surface of the heat conducting fins are clean. Also vacuum the filter (if this element is available). 6.Reinstall the cover.
7.Connect the refrigerator to the electrical connection.
Check the door packing
The door gasket is a component that must remain in good condition for the refrigerator to operate properly. To verify its status, proceed as follows:
1.Open the door.
2.Insert a strip of paper about 5 cm wide, between the door gasket and the lip of the refrigerator body where the gasket is housed.
3.Close the door.
- Gently pull the paper from the outside. The paper must have a resistance to being displaced outwards. If the paper can be removed without resistance, the packaging should be replaced. Perform this procedure every 10 cm around the entire perimeter on which the packaging acts. A packaging in poor condition causes several inconveniences in the operation of the refrigerator:
- Allows moisture to enter, which condenses and freezes inside the evaporator.
- Increases the compressoroperating timeto maintain the selected temperature.
- It affects the conservation of temperature.
- Increase operating costs.