1.) The principle of antifreeze
As we all know, at a standard atmospheric pressure, the freezing point of pure water is 0°C.
The laser source and its output QBH/QD are mainly cooled by circulating cooling water to ensure it works stably and reliably. The minimum temperature in winter is lower than zero degrees Celsius in most areas and regions. If the cooling water inside the laser source freezes and expands in volume, it will cause catastrophic damage to the laser source, increase your laser source maintenance and repair cost, and may even stop your production activities.
Ethylene glycol is a colorless, slightly viscous liquid with a boiling point of 197.4°C and a freezing point of -11.5°C. It can be mixed with water in any proportion. After mixing, the freezing point is significantly lowered due to the change in the vapor pressure of the cooling water. Therefore, water-based antifreeze based on ethylene glycol is widely used.
The typical values of the corresponding freezing point temperatures of ethylene glycol and deionized water at different volume percentages (ethylene glycol: deionized water) are shown in the table below:
|
ethylene glycol/deionized water (%)
|
Freezing temperature (°C)
|
| 10 |
-4.10
|
| 20 |
-7.50
|
| 30 |
-14.10
|
| 40 |
-22.90
|
| 50 |
-33.00
|
| 60 |
-50.00
|
Note 1: When ethylene glycol/deionized water (%) is about 60%, freezing point temperature of ethylene glycol aqueous solution is the minimum (about -50°C). Different ethylene glycol/deionized water ratio (%) will lead to different freezing point temperatures, which may not meet your use of your laser source.
Note 2: If ethylene glycol/deionized water ratio (%) is too large, the heat dissipation will be worse.
2.) How to use antifreeze
When using the laser cutting machine, if the minimum enviroment temperature is lower than 0°C, appropriate antifreeze measures must be taken. There are three main methods of antifreeze treatment in winter:
1. Keep the water chiller continuously running without stopping.
Under the circumstance that there is no power outage, if the minimum environment temperature is between -10°C and 0°C, the water chiller that supplies water to the laser
laser and QBH can be kept continous running to ensure that the temperature inside the laser source is higher than 0°C.
If the water chiller is shut down due to equipment failure or human factors, there will be a risk of damage to the laser source.
2. Replacing cooling water with antifreeze
When it is not possible to run the water chiller uninterrupted every day, the water chiller must be with antifreeze. The proportion of antifreeze must be correct and ensure that the antifreeze freezing point temperature is 5°C lower than the minimum enviroment temperature where the equipment is located.
It is recommended to use professional brand antifreeze. For example, Clariant has two models: Antifrogen® N ethylene glycol-water and Antifrogen® L propylene glycol-water.
When using antifreeze, proceed as follows:
Remove the water pipes of the fiber laser source inlet and outlet, then inject clean compressed gas from the laser source water inlet to drain all the cooling water inside the
laser source from the water outlet; use clean compressed gas less than 0.1 MPa to drain all the water inside the QBH. Excessive pressure should be avoided to damage the optical fiber.
Drain the cooling water in the water chiller and its pipes, and then pour the mixed antifreeze into the water chiller; connect the laser source and the water chiller, QBH and
the water chiller, and start the water chiller.
Note:
1. Please choose the ratio of antifreeze reasonably.
2. Any antifreeze is not suitable for long-term use throughout the year, so after winter, please replace it with normal deionized water in time, and clean the antifreeze in all waterways before replacing.
3. If the laser cutting machine is not used for a long time, it is necessary to drain clean coolant.
If the laser cutting machine is not used for a long time, the coolant in the laser source and QBH fiber must be drained completely. The detailed operations are as follows:
Remove the water pipes of the fiber laser source inlet and outlet, then inject clean compressed gas from the laser source water inlet to drain all the cooling water inside the
laser source from the water outlet. After no water flows out from the water outlet, keep blowing gas for 2 minutes to ensure that water is completely drained;
Inject clean compressed gas less than 0.1 MPa from the water inlet of the QBH, and drain the water stored in the QBH. Please avoid damage to the optical fiber due to excessive gas pressure.
Block the water inlet and outlet of the laser sorce and QBH to prevent dust from entering the laser source.
If you have any questions, feel free to contact our after-sales support.
