Four types of safety protection measures for refrigeration compressors

Four types of safety protection measures for refrigeration compressors

As the most important component of the chiller, the motor for the refrigeration compressor plays an important role in the after-sales maintenance of the chiller. Moreover, the maintenance cost of the chiller compressor is relatively high. In order to reduce the maintenance cost of the chiller, Najin Machinery protects the chiller compressor from the following four aspects. In order to achieve the purpose of reducing the maintenance cost of the chiller.

　　 One, prevent liquid shock

Under normal working conditions, the refrigeration compressor of an industrial chiller should inhale the dry vapor of the refrigerant. If the refrigerant flow is large, the heat load changes too quickly, or the operation is improper, it may inhale wet vapor, or liquid refrigerant, or even worse. If lubricating oil enters the cylinder, if too much liquid enters and is too late to be discharged from the exhaust valve, the pressure in the cylinder will rise sharply to form a liquid hammer, which will damage the cylinder, valve, piston, connecting rod and other parts. Therefore, various protective measures can be taken, such as installing a gas-liquid separator to separate the liquid entrained in the low-pressure vapor to ensure the dry stroke of the compressor; installing an oil heater to add lubricating oil before the compressor starts to reduce the solubility The amount of refrigerant in the lubricating oil; or the air valve assembly is pressed tightly on the end of the cylinder with a spring to form a false cover.

　　 2. Pressure protection

　　 1. Control of suction and exhaust pressure: that is, what we often call high and low pressure controllers, composed of a high pressure control part and a low pressure control part. If the discharge pressure exceeds a given value, the high-pressure control part cuts off the compressor power supply and the compressor stops; if the suction pressure is lower than the given value, the low-pressure control part cuts off the compressor power supply to stop the compressor and sends an alarm signal.

　　2. Safety valve: In order to prevent the refrigerant from leaking to the atmosphere, a closed safety valve is generally used. The safety valve is set on the pipeline between the discharge cavity and the suction cavity of the compressor of the chiller.

3. Safety diaphragm: The safety diaphragm is installed between the suction and exhaust chambers. When the pressure difference between suction and exhaust exceeds the specified value, the diaphragm will rupture and the exhaust pressure will decrease (a filter must be installed on the side of the suction chamber to prevent breakage. The diaphragm falls into the suction cavity).

4. Lubricating oil pressure difference controller: connect the inlet and outlet of the hydraulic pump to the low pressure inlet and high pressure outlet of the lubricating oil pressure difference controller. When the pressure difference between the outlet and inlet of the hydraulic pump is too high or too high When it is low, the controller will cut off the compressor power and the motor will stop running to protect the compressor.

　　 Three, the protection of the built-in motor

Overheating protection, in order to further ensure that the motor is not overheated, in addition to correct use and maintenance, an overheating relay can also be installed; there is also phase loss protection. If the commonly used three-phase motor lacks phase, the motor cannot be started or overloaded. Overload can be used The relay prevents the motor from being damaged due to lack of phase.

　　 Four, temperature protection

　　 The temperature mentioned here refers to the exhaust temperature and the temperature of the industrial chiller casing. The exhaust temperature protection method is mainly to place the thermostat close to the exhaust port. When the exhaust temperature is sensed, the thermostat will cut off the circuit; if the temperature of the casing of the unit is too high, it will affect the life of the compressor. It is caused by insufficient heat exchange capacity of the condenser, so check whether the air volume or water volume and water temperature of the condenser are appropriate. And check whether air or other non-condensable gas is mixed in the refrigeration system, or the temperature is too high, etc., should be observed and tested.