1、 Basic principles and methods of antifreeze
All liquids have“ Freezing point”, When the liquid temperature is lower than this“ Freezing point” When the temperature is high, it will solidify to form a solid, while the volume of deionized water or purified water will become larger during the solidification process, which will“ Broken” The pipes and sealing connections of the water cooling system are damaged. In order to avoid damage to the laser, output head and water cooler caused by solidification of cooling liquid, there are three solutions:
1. If there is absolutely no power failure in the local area, the water cooler will not be turned off at night. At the same time, to save energy, the temperature of low temperature and normal temperature water will be adjusted to 5~10 ℃ to ensure that the coolant is in circulation and the temperature is not lower than the freezing point.
2. Drain the cooling liquid in the laser, laser output head and water cooler after use every day.
3. Use antifreeze as coolant.
2、 Cooling water emptying method and pipeline design scheme reference
1. Schematic diagram of waterway connection:
2. Valve status in normal use (red off, yellow on):
3. Before shutdown, use the water cooler to actively drain:
When the water cooler is started, close the red valve and open the yellow valve. At this time, the water cooler actively pumps the water in the internal water tank into the water storage bucket until no large amount of water flows out.
4. Drain the residual water with low pressure air:
Close the red marker valve and open the yellow marker valve according to the requirements of the drawing, and supply clean compressed air or nitrogen no higher than 0.4Mpa (within 4kg) to point A until no water is blown out of the outlet at point B.
5. Water cooler outlet is normally open
Finally, open the drain port of the water cooler to drain the remaining water in the final water tank.
Note: All cooling water in the laser, laser output head, processing head and water cooler must be drained completely to effectively protect the whole set of water cooling pipeline and related devices!
3、 Use antifreeze
When the operating environment is frequently powered off and does not have the conditions to drain the coolant every day, antifreeze must be used. The base liquid of antifreeze is generally composed of alcohol and water. It requires high boiling point and flash point, high specific heat and conductivity, low viscosity at low temperature, no foaming, no corrosion to metal parts, rubber hoses, etc. When selecting or preparing antifreeze, its freezing point should be 5 ℃ lower than the lowest temperature of the use environment.
1. Use ethanol for short-term antifreeze:
If the power is cut off and the cooling water cannot be drained, and temporary short-term antifreeze is required, ethanol (alcohol) can be added to deionized or purified water, and the added amount cannot exceed 40% of the volume of the water tank. Because ethanol is highly corrosive, it can corrode grease, paint, rubber parts, and metal, so it cannot be used for a long time. It must be drained and cleaned with purified or deionized water within a week. If there are still anti freezing requirements, special antifreeze must be selected.
2. Use special antifreeze of professional brand:
It is recommended to select CLARIANT brand. There are two types of antifreeze suitable for laser system:
1) Antifrogen® N ethylene glycol water type (industrial product, toxic to human body)
2) Antifrogen® L propylene glycol water type (food grade, harmless to human body)
Note: Any antifreeze cannot completely replace deionized water and cannot be used for a long time all year round. After winter, the pipeline must be cleaned with deionized water or purified water, and the deionized water or purified water must be used as coolant again.
If conditions permit, we still suggest to improve the power environment, keep the chiller on, or upgrade the cooling water circuit design to make it easier and faster to drain the cooling water every day.
