How can I prevent the evaporator from freezing?

How can I prevent the evaporator from freezing?

1. Low pressure control switch

The focus of the low pressure control switch is to set the low pressure of the refrigerant and to warn of the leakage of the refrigerant. When the system is in operation, the control switch senses that the essential pressure is lower than the set pressure, it stops the shrink machine from running to prevent the pressure from falling continuously. When the evaporating pressure of the refrigerant decreases, the relative saturation evaporation temperature also decreases, increasing the likelihood of ice forming on the ice and water side, i.e. the low pressure control switch is also set to have an anti-freeze function. If the refrigerant temperature is below 0°C and the machine is shut down, the ice and water side of the ice and water may burst the plate.

2. Refrigerant-side anti-freeze switch

The performance of the anti-freeze switch is the same as the low pressure control switch, the difference is that the freeze switch is set for temperature rather than pressure, the refrigerant in the evaporator is the lowest temperature part of the freezing cycle system, if the refrigerant temperature control does not fall below 0 degrees, then the ice and water side that is no danger of freezing.

3、Water-side temperature control anti-freeze switch

Plate heat exchanger for evaporator, excluding the control of cold temperature to prevent the water side of the ice, but also directly control the water temperature to prevent freezing. The design of the ice and water side of the outlet to add a temperature-controlled anti-freeze switch to control the temperature of the cooling circulating water. Concern: The temperature sensor should be installed at the outlet of the chilled water of the evaporator. As the water side temperature sensor is not vivid than the cold side, so usually the water temperature control in more than 4 degrees, the water temperature is lower than the set temperature that line jump machine.

4、Flow switch

The key performance of the flow switch is to set the flow rate of the water side. When the water flow is lower than the set value when the system is closed to prevent the water from freezing in the heat exchanger, thus forming a split in the heat exchanger due to continuous freezing. The main reasons that can normally create a shortage of water are a broken pump and a split water pipe leak. Water pipes are pressed into. Choked water side piping, choked filters, no water in the ice and water tank, etc. Insufficient water will form the water side of the entrance and exit temperature difference becomes large, the refrigerant evaporation temperature drop, if the cycle continues, so that the water side of the temperature drops lower and lower, and the lack of water to form the flow field dispersion is uneven, easy to occur in the low flow rate area icing phenomenon.