Common auxiliary equipment and functions of refrigeration systems

                Common auxiliary equipment and functions of refrigeration systems

1. Oil separator

By utilizing the different densities of oil and refrigerant, when the channel cross-section suddenly increases and the flow rate drops sharply (from 10-25m/s to 0.8-1m/s), heavier oil droplets fall under the action of gravity; Changing the direction of gas flow inside the oil or utilizing centrifugation to separate high-density oil droplets; Using refrigerant liquid or cooling water pipes to cool the mixed gas and condense the oil vapor carried in it into larger oil droplets; Use filtering equipment to filter. From the perspective of appearance structure, it can be divided into vertical oil separation and horizontal oil separation.

2. Vapor-liquid separator

The function of the vapor-liquid separator is to prevent liquid droplets that have not evaporated in the evaporator from entering the compressor with the airflow, causing liquid hammer. Its structure is similar to that of an oil separator, and it also utilizes changes in velocity to cause droplets with greater gravity to settle down. Low pressure circulation drum is also a type of gas-liquid separator, which is an important equipment for gravity liquid supply system and pump liquid supply system. During operation, a certain liquid level must be maintained. Systems with different evaporation temperatures should be equipped with separate vapor-liquid separators.

3. Air separator

Another important equipment in the ammonia system is the air separator, which is used to discharge non condensable gases such as air in the system, especially for systems that often operate at low temperatures or below atmospheric pressure. For small and medium-sized Freon systems, air separators are usually not added, but are directly discharged from high-pressure equipment such as condensers.

4. Reservoir

A liquid reservoir is used in a refrigeration system to store the refrigerant liquid condensed by the condenser; Adjust the supply and demand relationship of refrigerant liquid between the condenser and evaporator; Preventing the refrigerant gas from the high-pressure system from leaking into the low-pressure system (liquid seal) is called a high-pressure reservoir.

5. Discharge bucket

Mainly used in gravity liquid supply systems to accommodate refrigerant liquid discharged during hot air defrosting. Its structure is the same as that of a high-pressure liquid storage tank.

6. Low pressure circulation drum

The low-pressure circulation bucket is a key equipment in the pump supply system. Its function is to store and maintain a certain amount of liquid, stabilize the low-pressure refrigerant liquid required for the circulation pump, and also act as a vapor liquid separator. If necessary, it can also serve as a discharge bucket. The structure is basically similar to that of a gas-liquid separator.

7. Oil collector

The oil collector is an important equipment in the ammonia system, used to recover and discharge lubricating oil accumulated in various equipment in the system. The oil collector consists of a barrel body, an oil inlet valve, an oil drain valve, a return valve, an oil sight glass, and a pressure gauge.

8. Oil cooler

The lubricating oil separated from the oil increases in temperature (close to the exhaust temperature) due to the absorption of frictional heat and gas heat. The normal operating temperature of lubricating oil is 30-60 ℃. If the oil temperature is too high, the viscosity will decrease, weaken the sealing effect, increase internal leakage, and reduce the efficiency of the compressor. Therefore, lubricating oil must be cooled before it can be recycled. The oil cooler serves to cool the oil.

9. Oil filter

To protect the normal operation of the oil pump, impurities are filtered out through a coarse oil filter before lubricating oil enters the pump. The filter is composed of a shell and a metal filter screen, and there is a refueling valve on the shell, which is used for initial refueling. Refueling can be done through the system vacuum pumping or through the oil pump. For the initial operation of the machine, the cleanliness of the crude oil filter should be checked after the initial operation, and the filter screen should be regularly disassembled and inspected according to the system cleanliness.

10. Suction filter

The suction filter mainly consists of a shell and a metal filter screen. The suction filter is used to eliminate impurities in the medium and protect the normal use of valves and equipment

11. Oil pressure regulating valve

The function of the oil pressure regulating valve is to regulate the fuel injection pressure of the compressor. If the oil pressure entering the compressor is too high, it will cause excessive fuel injection, which not only affects the suction volume of the compressor, but also increases the power consumption of the compressor, and also increases the possibility of shaft seal oil leakage; If the oil pressure is too low, it will cause the fuel injection to be too small, weakening the effect of lubricating oil.

12. Regulating station

In ammonia refrigeration systems, especially for large and medium-sized cold storage units (over 500t), the refrigeration system usually has multiple evaporation temperatures and multiple liquid supply pipelines. In order to meet the requirements of refrigeration technology, throttle valves need to be installed on each evaporation temperature or supply pipeline to control liquid and gas. The regulating station is actually a valve group that centralizes all throttle valves for easy operation. The regulating station includes the overall liquid regulating station in the computer room and the liquid and gas sub regulating station in the warehouse.

13. Supply pump

Supply pumps, especially solution pumps, play an important role in ammonia refrigeration systems. Main function: Provide normal circulation flow, ensure the absorption of ammonia in the absorber, and improve the efficiency of the refrigeration system. Improve the efficiency of the refrigeration system.

14. Evaporator pressure regulating valve

Also known as the evaporative pressure regulating valve or pressure reducing valve, it is a key component in the steam system. Its main function is to maintain the stability of the evaporation pressure in various parts of the refrigeration system and prevent the evaporator pressure (and evaporation temperature) from dropping below the specified value. In some cases, the evaporator pressure regulating valve is also used to adjust the load of the evaporator to adapt to changes in system load.

15. Oil pressure protector

Used to monitor and protect the pressure of lubricating oil to prevent damage to the system caused by low or high oil pressure.