Information about freezer warehouses and freezer machines used in ships is provided.
Modern end-of-the-day cold-storage vessels are thought of as fully flexible, multi-purpose reefer vessels and are transported to the world as freight chests and pallets. Cold-water vessels are particularly large four-cornered warehouses with a wide range of cooling temperatures from -30 to 13 in terms of transport of bananas, citrus fruits, eggs, chickens and frozen meat.
Reefer ships also carry containers of 40 feet of self-cooled electric power from 30 tons at full load on the hatch covers as a deck load. The grenade has the ability to evacuate very quickly with its own cryosphere. For this purpose, the hatch covers have the possibility of locking them securely.
Containers are manufactured from steel sheets, 20-40 feet long, 8 feet and 8 feet high. The modern cold weather warehouses can go 19-20 mph, as the reefer vessels carrying bananas make 22-25 mph.
In cold weather storage vessels, it is the most important task to discharge the load very quickly. In terms of providing quickness in the pouring and the banana evacuation, the gates are unloaded from the openings on the banks, from the wide hatches to the crayons and conveyors.
Preservation of heat in warehouses
Warehouses, warehouse curtains and glass bottoms under the hatch cover are laid in the warehouses to prevent heat losses.
Freezer Machines
Salt water is circulated through the pipes. In the storage rooms, aluminum pipes are wrapped around the salt water pipes in the warehouses. Cold air is distributed around with powerful fans.
Properties of Oil Used in Freezing Machines
In compressors under 75 kW, the bearing lubrication is achieved by impact. In larger iceboxes and compressors, bearing lubrication is provided by a gear pump. In this case, the heated oil passes through the oil valve and is cooled down to 50ºC. It is essential to use the appropriate number of oil in refrigerating compressors. The cooling compressor oil must carry the following characteristics.
– Do not enter the chemical reaction with the refrigerant in any way.
– Do not make carbons in piston rings in compressor valves.
– The viscosity should not change so that good bearing lubrication can be achieved.
– The oil should not be able to clog the thin holes by waxing at low temperature (-10, -20).
– There should be no moisture inside.
Oils used in refrigeration compressors are more expensive than other oils and sold in decisive containers. The oils recommended by the producer company should be used.
Compressor Oil Installation
– Suction valve closed.
– The sucking manometer is operated at least slightly above the atmospheric pressure, that is, until it shows approximately zero.
– Stop the compressor.
Oil Seperators
In larger systems, an oil separator is installed on the outlet side of the compressor to get more oil from the system. Excess oil must be drained from the separator chamber. Oil separators usually have a return line to the compressor casing, which is controlled by a float. If the oil consumption increases, it is checked whether the float valve is working correctly and whether the oil return line is blocked. Oil must be separated from freon gas. Because oil weakens heat transfer.
Mixing of Air to Cooling System
If air or other non-condensing gases accumulate in the system, they form an insulation layer in the condenser, causing the outlet temperature and pressure to rise. For efficient operation, the facility should be cleaned to remove air. For taking air from the cooling system;
– The fluid valve after the tank is switched off and the compressor is operated for a few minutes.
– The compressor is stopped and the outlet shutoff valve is closed.
– To allow air to accumulate in the highest area, the system is left for a while before the compressor is started.
– The blind cap is removed and the discharge valve at the highest point of the system opens in a controlled manner (usually on the condenser).
– It is ensured that the system is evacuated for approx. 30 seconds.
– The process is repeated until all air is evacuated.
– At the end of the work the blind lid is closed again.
– The system is operated for a period of time to check the suction and discharge pressures and temperature ratings after the release of the air and the completion of the load. The indicators may indicate that the system is underloaded or overloaded.
– The liquid temperature at the outlet of the condenser is controlled and this value is compared with the saturation temperature corresponding to the outlet pressure. If there is a noticeable difference, then there is air in the system.
Moisture Effect
After installation and repair, humidity traces remain on the system and cause internal corrosion. For this reason, it is necessary to purify the nod before giving gas. A low pressure environment is created to provide water evaporation.
Filter dryers are used to hold moisture residues in the cooling system.
Source: SVET