Fiber Laser Source Antifreeze Guide

1. Antifreeze principle

The cooling water has a "freezing point". When the ambient temperature is lower than the "freezing point" of the coolant used in the chiller, the coolant will solidify, and it will expand when it solidifies. This causes the over-current components in the laser cooling system, such as water-cooled plates, water dividers, and other components to expand and deform, or even burst. For a high-power laser source, the core optical components are all mounted on the water-cooling plate. The expansion of the water-cooled plate will directly cause the laser to be returned to the factory for repair. Thereby bringing greater economic losses to users.

Therefore, anti-freezing measures for the laser must be done.

2. Antifreeze solution

    2.1 Keep the water chiller non-stop

When the local power supply is stable, the chiller can be kept running, and both low-temperature water and room temperature water are set to 5°C (to ensure that the cooling water is higher than the freezing point while saving electricity).

Note:

        (1) When the machine working environment temperature is ≥5°C, the water chiller could use the electrical heating mode (automatic intermittent opening);

         (2) When the machine working environment temperature is less than 5°C, the water chiller will needs to use continuous cooling mode (automatically and continuously open);

        (3) Regardless of the working model of the water cooler, the laser and laser (low pressure) need to be turned on to maintain the water circulation, and other auxiliary equipment can be turned off;

        (4) When the equipment is working normally, the water chiller must be kept in continuous cooling mode;

        (5) If the shutdown is for a long time, the water tank should be drained, and clean air should be used for deep emptying treatment, and the water in the water pump and the water cooler filter should be drained at the same time;

        (6) When the water temperature is lower than 18°C, the laser cannot work. You must wait for the water temperature to rise above 18°C before turning on the laser.

    2.2 Drain the cooling water in the machine

Drain the cooling water in the laser and water cooler after each use.

Drainage method:

         (1) Remove the water pipe of the water inlet from the chiller, and ventilate the water inlet (WATER IN) with compressed air until all the residual water in the chiller is blown out.

         (2) Then, remove the water pipe at the water inlet from the fiber laser source, and then ventilate the water inlet with compressed gas until all the residual water in the water-cooling pipe inside the laser source is blown out from the water outlet.

         (3) Plug the water inlet and outlet with water pipes (or rubber plugs) to prevent dust from entering the inside of the machine.

    2.3 Replace cooling water with antifreeze

When the circuits in the machine working environment are often power cut and do not have the conditions to drain the coolant every day. The machine must use antifreeze. The basic liquid of antifreeze is generally composed of water and alcohol. It requires a high boiling point and flash point, high specific heat, and good thermal conductivity. Low-temperature viscosity is small, not easy to foam, and does not corrode metal parts and rubber hoses. When selecting and deploying antifreeze, its freezing point should be 5 degrees Celsius lower than the minimum temperature of the equipment operating environment.

Note: any antifreeze cannot completely replace deionized water, cannot be used for a long time throughout the year, and the use volume accounts for 10%-20% of the water tank volume, not more than 20%. When winter passes, clean water or deionized water must be used to clean the entire waterway. The water path includes the cooling circuit of the laser, the filter of the chiller, the water path of the chiller, the cooling circuit of the laser head, all the water inlet pipes, and all the water outlet pipes. After cleaning, please use pure water or deionized water as the coolant, and replace it within 1-2 months.

3. How to choose antifreeze

The full name of antifreeze should be called antifreeze coolant, which means coolant with antifreeze function. Used to prevent freezing of water chillers in winter. The chiller has the following requirements for the performance of antifreeze:

     (1) Good antifreeze performance;

     (2) Anti-corrosion and anti-rust properties;

     (3) It has no swelling and corrosive performance to the rubber sealing tube;

    (4) Low-temperature viscosity is not too big;

    (5) Stable chemical properties.

There are many types of antifreeze: inorganic substances, such as calcium chloride (CaCl2), sodium chloride (NaCl), etc.; organic substances such as methanol (CH3OH), ethanol (C2H5OH, common name alcohol), ethylene glycol (C2H4 (OH) 2. Common name sweet alcohol), propylene glycol (C3H6(OH)2), glycerol (C3H5(OH)3, common name glycerin), diethylene glycol (C4H7(OH)3, common name diethylene glycol), etc. As the mother liquor of antifreeze. After adding an appropriate amount of pure soft water (water with no or a small amount of calcium and magnesium ions, unpolluted rainwater, snow water, etc., the total hardness content of the water quality is between 0-30ppm), it can become a general sense Of antifreeze.

Sodium chloride and other solutions are highly corrosive, methanol and ethanol are volatile, propylene glycol and diethylene glycol have moderate viscosity, but the price is relatively expensive, although glycerol is not expensive, the viscosity is too large, and the price of ethylene glycol is not high. Moderate but low toxicity. Most of the types of antifreeze used at home and abroad are water-based antifreezes of ethylene glycol and propylene glycol. The types of antifreeze currently available on the market have been prepared with a concentration of 100% antifreeze. This kind of antifreeze can be used directly. One is the mother liquid of antifreeze, that is, concentrated type. Concentrated antifreeze generally cannot be used directly, but should be adjusted to a certain concentration with demineralized water according to the temperature requirements. It should be noted that some of the brand types of antifreeze on the market are compound formulas, which are added with anti-corrosion and viscosity adjustment additives.

(1) Ethylene glycol water-based solution:

The freezing point of glycol type antifreeze changes with the concentration of ethylene glycol in the aqueous solution. When the volume concentration is below 56%, the ethylene glycol concentration in the aqueous solution increases, and the freezing point decreases, but when the volume concentration exceeds 56%. As the concentration of ethylene glycol increases, its freezing point shows an upward trend. When the concentration reaches 100%, its freezing point rises to -13°C. This is why concentrated antifreeze (antifreeze mother liquor) cannot be used directly the reason.

For example: in areas where the lowest temperature is -5℃, a glycol type antifreeze with a volume concentration of 12.8% can be used, and in areas where the lowest temperature is -10℃, a glycol type with a volume concentration of 22.0% can be used Antifreeze: In areas where the lowest temperature is -30℃, use a glycol type antifreeze with a volume concentration of 43.8%.

(2) Propylene glycol water-based solution:

The selection principle of propylene glycol water-based antifreeze and glycol water-based antifreeze is the same, not that the higher the concentration, the better the antifreeze effect, but the most suitable concentration should be determined according to the specific conditions of use.

(3) Ethanol water-based solution:

Ethanol and water can be mixed in any ratio to form antifreeze with different freezing points. The higher the ethanol content, the lower the freezing point. Ethanol is a flammable product. When the ethanol content in the antifreeze reaches more than 40%, it is easy to produce alcohol vapor and catch fire. Therefore, the ethanol content in the antifreeze should not exceed 40%, and the freezing point should be limited to about -30°C. Ethanol-based antifreeze has good fluidity, convenient materials, and simple preparation. The disadvantage is that it is easy to catch fire, low boiling point, and large evaporation loss. After the ethanol evaporates, the composition of the antifreeze will change and the freezing point will rise. It is not suitable to use ethanol type antifreeze in mountainous and plateau areas because the evaporation loss of ethanol is large.

Most of the antifreeze (ethylene glycol, propylene glycol, etc.) supplied on the market are suitable for the chillers supplied by our company. The greater the concentration of antifreeze, the greater the corrosion of the mechanical seal material of the pump. (For example concentration of glycol antifreeze. At 30%, the life of the pump mechanical seal will be shortened by more than half.) The greater the concentration of antifreeze, the greater its viscosity, and the load on the pump motor will increase. In some cases, the pump motor will be overloaded and damaged. Therefore, when the antifreeze performance is satisfied, the lower the concentration of the antifreeze, the better. The selection of antifreeze should also consider the specific application environment, (for example, semiconductor lasers and fiber lasers require the use of deionized water as the coolant, so it is not appropriate to add antifreeze);

Finally, summarize three important principles that need to be paid attention to during the use of antifreeze:

     (1) The lower the concentration, the better. Most antifreeze fluids are corrosive, and if the antifreeze performance is satisfied, the lower the concentration, the better.

     (2) The shorter the use time, the better. The antifreeze fluid will deteriorate to a certain extent after it is used for a long time. After the antifreeze fluid deteriorates, it will be more corrosive and the viscosity will also change. Therefore, it needs to be replaced regularly, and the replacement cycle is recommended to be replaced once a year. Use pure water in summer and replace it with new antifreeze in winter.

     (3) Not suitable for mixing. Try to use the same brand of antifreeze. Even if the main components of different types of antifreeze are the same, their additive formulas will be different. They should not be mixed to avoid chemical reactions, precipitation, or bubbles.

It is recommended to use professional antifreeze brands. Please refer to the following content for matching when using the CLARTANT brand. If you use other brands of antifreeze, please do not use it with water.

The CLARTANT, the antifreeze suitable for the laser system has the following two models:

     (1) Antifrogen R N -- Ethylene glycol -- water type (industrial products, harmful to humans);

     (2) Antifrogen R L -- Propylene Glycol -- water type (food grade, harmless to humans).

The ratio of the CLARTANT antifreeze is based on the lowest temperature each year, combined with the actual usage, and the following conclusions are drawn after testing: (for buyers' reference only)

     (1)6:4 (60% antifreeze, 40% water) minus 42°C - minus 45°C;

     (2)5:5 (50% antifreeze, 50% water) minus 32°C - minus 35°C.

Note: If the machine is shut down for a long time (such as Christmas holidays) or the laser is transported, the cooling water in the equipment must be drained. And use compressed air to blow out the residual water in the equipment (including the laser and the chiller), so that the internal ice will damage the device.

4. Precautions for laser chiller

     It is strictly forbidden to start the water machine without water, and it is strictly forbidden to short-circuit the signal line of the water machine. The machine must be placed in a dry, ventilated place and not exposed to direct sunlight. The air outlet of the integrated water machine must not be blocked. The front is 1 meter. There should be no obstacles within the area, and the water pipes should not be broken to ensure ventilation, heat dissipation, and smooth water flow.

The normal temperature of the water machine is set in the range of 23-24°C. The water machine will give a low-temperature alarm due to the weather. The correct way is to turn on the water machine first and let the water machine energize for a period of time, or you can use a heater to properly boil it. Water, in this case, the machine heats up considerably faster, or the temperature of the place where the water machine is placed must be kept above 12°C.

5. Recommendations for storage of the chiller when not working in the cold winter:

     5.1 If the equipment is shut down for a short period of time, it is recommended to start the chiller separately and let it run continuously to maintain normal working water temperature. And always pay attention to the running status of the chiller to prevent power failure.

     5.2 If the equipment does not work at night, and if it is determined that there will be no power failure, please start the chiller separately. For energy saving considerations, set the water temperature of the low-temperature system and high-temperature system to 5～10℃ (single temperature The same applies to chillers). Ensure that the coolant is in a circulating state and the water temperature is not lower than the freezing point.

     5.3 If the machine is shut down for a long time, be sure to drain the coolant inside the chiller and drain the coolant inside the water tank, heating rod housing, water pump, filter, and heat exchanger with nitrogen. (If the cooling liquid cannot be discharged due to environmental constraints, please refer to step 2 to ensure that the cooling liquid is in a circulating state and the water temperature is not lower than the freezing point)

PS: If the water chiller that drains the water is started for the first time after adding water, the air in the pipe may cause a low flow rate and then a water flow alarm. If this happens, please use the exhaust hole of the water pump to circulate the water Exhaust operation, or restart the pump several times at intervals of 10-20 seconds.

Name: Arisa Yin

Email: arisa@leapion.com

WeChat/WhatsApp: +86 153 1541 6150  https://api.whatsapp.com/send?phone=8615315416150