Key Points of Screw Chiller Maintenance!
The temperature difference at the end of the screw machine is the basis for judging whether the shell and tube is too dirty. If you don't know the temperature difference at the end, it is difficult to judge whether the shell and tube are fouled? Does it affect the heat exchange of the unit? Does it need to be cleaned? After learning the calculation method of the end temperature difference, you have learned the judgment standard.
First check the operating parameters through the controller
Check the operating parameters of the unit after starting up, focusing on the chilled water inlet and outlet temperature, the chilled water inlet and outlet temperature, the condensing pressure and the evaporation pressure.
Calculating terminal temperature difference
Convert the condensation pressure and evaporation pressure into the corresponding condensation saturation temperature and evaporation saturation temperature. If the condensation temperature and evaporation temperature can be queried on the touch screen, this value is the corresponding condensation saturation temperature and evaporation saturation temperature.
If the end temperature difference is greater than 5°C, it can be preliminarily judged that the heat exchanger has scaled. When the end temperature difference is greater than 7°C, the scale will be serious.
Example: Condensing end temperature difference = 36°C-32.3°C = 3.7°C, evaporation end temperature difference = 12.1°C-9.7°C = 2.4°C, it can be seen that the condensation end temperature difference and the evaporation end temperature difference are both small, and the shell and tube heat exchange effect is better, basically no Scaling.
If the temperature difference at the calculation end is too large, the water quality can be checked:
1. Check the water quality of the cooling tower to be clear and free of deposits, floating objects, algae and other impurities. If you check that the cooling water is turbid and the filler is fouling, and the temperature difference between the ends is greater than 5°C, it can be confirmed that the heat exchanger shell and tube are fouling.
2. Frozen water quality: Use a clean transparent water bottle to take water from the chilled water outlet and observe whether it is turbid. Shake the water bottle to see if there are suspended particles. Leave it to observe whether there is deposits on the bottom of the water bottle.
If the chilled water is turbid and the temperature difference between the ends is greater than 5℃, it can be confirmed that the heat exchanger shell and tube are fouling.