1. How to maintain the refrigeration unit of the cold storage?
(1) In the early stage of the operation of the refrigeration unit, pay attention to whether the oil level of the compressor is at 1/2 from the oil sight glass; whether the cleanliness of the lubricating oil is good. If it is found that the oil level drops beyond the standard or the lubricating oil is too dirty, it should be solved in time to avoid poor lubrication.
(2) For the air-cooled unit: clean the surface of the air-cooler frequently to keep it in a good heat exchange state.
(3) For the water-cooled unit: the turbidity of the cooling water should be observed frequently. If the cooling water is too dirty, it should be replaced.
(4) Pay attention to check whether the cooling water supply system of the unit is running, running, dripping or leaking. If there is, it should be dealt with in time.
(5) Whether the working state of the water pump is normal; whether the valve switch of the cooling water system is effective; whether the working state of the cooling tower and the fan is normal.
(6) For the air-cooled evaporator: it is necessary to check whether the defrosting state is normal; whether the defrosting effect is good, and if there is a problem, it should be dealt with in time.
(7) Pay attention to observe the running state of the compressor, check whether the exhaust temperature and pressure value are within the normal range, and deal with it in time if there is any problem.
2. Determine whether the working state of the condenser is normal
If you do not know whether the working state of the condenser is normal, you can check whether it is working normally by detecting the temperature difference between the condenser and the cooling medium. The condensing temperature of the water-cooled condenser is 4~6℃ higher than the cooling water outlet temperature, and the condensing temperature of the evaporative condenser is related to the temperature of the air, which is about 5~10℃ higher than the outdoor wet bulb temperature. The condensing temperature of the air-cooled condenser is 8~12℃ higher than the air temperature.
3. Compressor suction temperature control range
The suction superheat of the compressor in the refrigeration system should generally be controlled within the range of 5 to 15 °C, and the suction temperature of the compressor in the Freon refrigeration system should generally be about 15 °C higher than the evaporating temperature, but in principle, it should not exceed 15 °C. Because the evaporating temperature of the refrigeration system of different cold storages is different, the suction temperature value is also different.
4. The danger of compressor suction temperature that is too high or too low
If the suction temperature of the compressor is too high, the suction specific volume of the compressor will increase, the cooling capacity will decrease, and the exhaust temperature will increase;
If the suction temperature of the compressor is too low, too much liquid may be supplied to the refrigeration system, and the liquid refrigerant will not be fully vaporized in the evaporator, which will cause a wet stroke. Pay attention to adjustment at any time.
5. What should I do if the refrigeration system of the cold storage is deficient in fluorine?
During the operation of the refrigeration system of the cold storage, in many cases, the refrigerant is leaked due to the lack of tightness of the system or during maintenance operations (such as oil change, air release, filter dryer replacement, etc.), resulting in insufficient refrigerant in the refrigeration system. At this time, it should be supplemented in time to ensure the normal operation of the refrigeration system.
The refrigeration system is supplemented with refrigerant, and the preparation before charging is the same as the main point of charging a new refrigeration system, except that there is refrigerant in the system before charging, and the compressor can still run.
The refrigeration system is supplemented with refrigerant, which is generally charged from the low-pressure side of the compressor.
The operation method of the cold storage refrigeration system is deficient in fluorine: when the compressor is stopped, place the refrigerant cylinder on the ground, use two fluorine pipes when filling the refrigerant, connect a repair valve in series between them, and then Connect one end of the fluoride pipe to the cylinder, and the other end to the multi-purpose channel of the suction valve of the compressor. First open the valve of the freon cylinder, use the refrigerant vapor to drain the air in the fluorine pipe, and then tighten the interface between the fluorine pipe and the multi-purpose channel of the compressor suction valve.
Open the multi-purpose channel of the compressor suction valve into a three-way state. When the pressure gauge on the repair valve is seen to be stable, temporarily close the freon cylinder valve. Start the compressor to run for about 15 minutes, and observe whether the operating pressure is within the required range. If the operating pressure cannot be met, the freon cylinder valve can be opened again, and the refrigerant will continue to be replenished into the refrigeration system until the operating pressure is reached. Since this method of replenishing the refrigerant is that the refrigerant is charged in the form of wet vapor, it is necessary to open the valve of the Freon cylinder properly to prevent the compressor from liquid hammer. When the charging meets the requirements, immediately close the freon cylinder valve, and then let the refrigerant remaining in the connecting pipe be sucked into the system as much as possible, and finally close the multi-purpose channel, stop the compressor operation, and the refrigerant charging work is basically over. This method has a slower charging speed, but has good safety when the refrigerant in the refrigeration system is insufficient and needs to be replenished.
6. What should I do if I want to regenerate the silica gel desiccant?
The moisture absorption rate of silica gel desiccant is about 30%. It is a non-toxic, odorless and non-corrosive translucent crystal block with coarse pores, fine pores, primary color and discoloration. Coarse-pored silica gel absorbs moisture quickly, is easy to be saturated, and has a short use time: fine-pored silica gel absorbs moisture slowly and has a long use time; color-changing silica gel is sea blue when it is dry, and gradually changes to light blue, purple-red, and finally brown after moisture absorption Red and loses hygroscopic ability.
The regeneration of silica gel desiccant can be done by placing the silica gel ready to be dried and regenerated into an oven for heating and regeneration. Set the oven temperature to 120~200°C, and set the heating time to 3~4h. After regeneration treatment, the silica gel desiccant can remove the moisture absorbed inside and restore it to its initial state. After sieving off the broken particles, it can be put into a drying filter for repeated use.
Post time: Jun-21-2022
