The selection and maintenance of ultra-low temperature chiller

Today, a customer came to inquire about our need for a small laboratory water chiller. The specific working condition is to reduce the materials in the 20L stainless steel reactor from normal temperature to minus 30 ℃ in more than one hour. This product is too simple for us. The LT-50 series chiller can easily meet all the operating conditions. For model selection, please remember the basic formula: tank volume (or material weight) * material specific heat * temperature difference/second.

Then, maintenance plays a key role in the stable operation of the equipment. After shutdown, start to use the refrigerant recovery device to recover refrigeration.

After the refrigerant is recovered, open the end cover of the water chamber, clean the circulating water system, and replace the oil filter element; After maintenance and installation, vacuum the system with a vacuum pump and maintain the pressure for 24 hours to ensure good airtightness. In the process of filling refrigerant, it is found that the refrigerant cannot be inhaled. It is confirmed that the system is leaking water, and then find the leak point. First, close the inlet and outlet valves at the water side of the evaporator and condenser. After the water inside the machine is drained, open the covers at both ends of the water side of the evaporator and condenser and fully close the outlet valve of the compressor to form a closed space. Refill refrigerant and mark the leakage point. Then, the evaporator and condenser are dried to remove the residual air in the system. Repeat this for many times to ensure that all the air in the system is discharged. Open the bottom corner valve to drain the residual liquid water in the system. Repeat flushing until no residual liquid water is discharged; Finally, the compressor shall be treated by removing the motor first and then drying it, and the withstand voltage test shall be carried out by professionals; Then conduct overall inspection and maintenance, replace damaged parts, and then assemble the compressor as a whole.

The above is about the selection and maintenance of ultra-low temperature chiller. Later, we will talk about the matters needing attention during installation and use.