Cooling liquid for plasma cutting system and preparation method thereof

Abstract

The invention belongs to the technical field of cooling liquid preparation, and particularly relates to cooling liquid for a plasma cutting system and a preparation method of the cooling liquid. The cooling liquid is prepared from the following components in percentage by mass: 25 to 65 percent of dihydric alcohol, 0.05 to 0.5 percent of a corrosion inhibitor, 0.02 to 0.2 percent of an antioxidant, 0.01 to 0.1 percent of a nonionic surfactant, 0.01 to 0.2 percent of a sterilizing agent, 0.001 to 0.01 percent of a de-foaming agent and the balance of water. The cooling liquid provided by the invention not only has the functions of heat dissipation, corrosion resistance and the like of the traditional cooling liquid, but also can keep the low conductivity of the cooling liquid, and meets the requirement of the normal operation life cycle of the plasma cutting system.

Description

Technical Field

[0001] The invention belongs to the technical field of coolant preparation, and in particular relates to a coolant for a plasma cutting system and a preparation method thereof. Background Art

[0002] Plasma cutting systems use plasma gas to transfer energy to a conductive workpiece material. Plasma gas is typically created by forcing a gas (such as nitrogen, oxygen, argon, or even air) through a narrow nozzle. An electric current generated by an external power source provides enough energy to ionize the gas stream, converting it into a plasma arc at temperatures approaching 20,000°C. The plasma arc cuts by melting the workpiece and blowing away the molten metal. The plasma in the plasma chamber can reach temperatures of tens of thousands of degrees Celsius and has an extremely high energy density, requiring efficient water cooling to remove the heat and ensure the proper operation of the plasma cutter.

[0003] The water cooling system for a plasma cutter is very similar to the water cooling system used in a car engine: Both use a circulating pump to force coolant through a heat exchanger to remove heat from a heat source. In a car, the heat source is the combustion chamber within the engine, which operates at temperatures exceeding 2000°F. In a plasma cutter, the heat source is the plasma chamber within the cutting torch, where arc temperatures can exceed 20,000°F.

[0004] If the coolant's conductivity is too high, the coolant in the cutting torch may become conductive, making it difficult to start the plasma arc when the torch triggers the arc between the electrode and the nozzle. Furthermore, when operating at high power, the plasma cutting power supply can draw up to 300-400 amps. If a component in the cooling system fails, causing a coolant leak, it could cause the equipment to short-circuit and burn the torch and cable, leading to a safety incident. Therefore, the cooling system of plasma arc cutting equipment requires the use of low-conductivity coolant to ensure safe and stable operation of the equipment. Conductivity is generally required to be less than 10μS / cm. Conventional engine coolants, which often contain inorganic salt or organic carboxylate corrosion inhibitors, have very high conductivity and are not suitable for plasma cutting systems.

[0005] However, considering that ion precipitation in the plasma cutting system and cooling pipes will increase the conductivity of the coolant, it is easy to make it difficult to start the plasma arc. Therefore, the plasma cutting system requires a special coolant that can not only perform the heat dissipation and corrosion protection functions of traditional coolants, but also maintain low conductivity.

[0006] It's worth noting that while water can be used as a coolant in the short term, long-term use can cause hard scale or dirt to form on the cutting head surface, affecting the machine's normal operation and lifespan. Therefore, a specialized plasma cutting machine coolant is required. Furthermore, when using a plasma cutting machine in winter, attention should be paid to antifreeze measures to ensure the proper operation of the cooling system. Summary of the Invention

[0007] The object of the present invention is to provide a coolant for a plasma cutting system and a preparation method thereof, wherein the coolant can not only play the heat dissipation and corrosion protection functions of traditional coolants, but also maintain the low electrical conductivity of the coolant.

[0008] In order to achieve the purpose of the present invention, the following technical solutions are specifically adopted:

[0009] A coolant for a plasma cutting system comprises the following components:

[0010]

[0011] Preferably, the diol is one of ethylene glycol, diethylene glycol, 1,2-propylene glycol, and 1,3-propylene glycol, or a mixture of two or more thereof. The diol in the present invention can be used as an antifreeze agent for the coolant to effectively lower the freezing point and increase the boiling point of the coolant.

[0012] Preferably, the corrosion inhibitor is one or a mixture of two or more of benzotriazole, 5-methylbenzotriazole, and 5-aminobenzotriazole. Using these azole compounds as corrosion inhibitors not only improves the corrosion resistance of the coolant itself, but also provides excellent corrosion protection for various metal materials used in plasma cutting systems, without causing metal ion leaching and increasing the coolant's conductivity.

[0013] Preferably, the antioxidant is one or a mixture of two or more of inositol, quercetin, xylitol, erythritol, sorbitol, mannitol, lactitol, maltitol, and isomalt. Using the above alcohol compounds as antioxidants can prevent the oxidation of diols.

[0014] Preferably, the nonionic surfactant is an aminoglycoside; more preferably, it is one or a mixture of two or more of acamycin, isopamicin, natilmicin, and gentamicin. Studies have shown that the addition of these aminoglycosides to the coolant of the present invention can effectively remove free ions from the coolant, maintaining a low electrical conductivity.

[0015] Preferably, the corrosion inhibitor is benzotriazole, the antioxidant is lactitol, and the nonionic surfactant is an aminoglycoside compound. Studies have found that the ternary synergistic system formed by benzotriazole, lactitol, and aminoglycoside can effectively inhibit ion precipitation in a plasma cutting environment.

[0016] Preferably, the bactericide is a mixture of glutaraldehyde and cinnamaldehyde; further preferably, the mass ratio of glutaraldehyde to cinnamaldehyde is 1:0.5-1.5. Studies have found that when glutaraldehyde and cinnamaldehyde are used in combination, they can produce an excellent bactericidal synergistic effect, which can prevent the growth of microorganisms in the coolant during long-term use in a high-temperature plasma environment.

[0017] Preferably, the defoaming agent is one or a mixture of two or more of an organosilicon defoaming agent, a polyether defoaming agent and a polyether-modified organosilicon defoaming agent, which has good defoaming and anti-foaming capabilities and is used to prevent the coolant from generating bubbles during operation.

[0018] Preferably, the coolant for the plasma cutting system is composed of the following raw materials in the following mass percentages:

[0019]

[0020]

[0021] On the basis of being in accordance with the common sense in this field, the above-mentioned preferred conditions can be combined with each other to obtain the preferred embodiments of the present invention.

[0022] The present invention also provides a method for preparing the coolant for the plasma cutting system, comprising the following steps:

[0023] (1) mixing diol and deionized water to obtain a diol solution;

[0024] (2) passing the glycol solution through an anion-cation mixed bed exchange resin (used to remove impurities such as anions and cations in the glycol solution and reduce the conductivity of the coolant);

[0025] (3) adding a corrosion inhibitor, an antioxidant, a nonionic surfactant, a bactericide, and a defoaming agent to the solution obtained in step (2), stirring until the solution is completely dissolved, and obtaining a coolant for a plasma cutting system.

[0026] Compared with the prior art, the fuel cell coolant of the present invention has the following advantages and effects:

[0027] (1) The coolant for the plasma cutting system provided by the present invention adopts a new non-ionic additive formula, which can not only play the heat dissipation and corrosion protection functions of traditional coolants, but also maintain the low electrical conductivity of the coolant, is suitable for the plasma cutting system, and meets the requirements of the normal operation life cycle of the plasma cutting system;

[0028] (2) The coolant for the plasma cutting system provided by the present invention can effectively remove free ions in the coolant and continuously maintain low conductivity of the coolant by adding a specific aminoglycoside compound as a non-ionic surfactant;

[0029] (3) In the coolant for a plasma cutting system provided by the present invention, the corrosion inhibitor is preferably benzotriazole, the antioxidant is lactitol, and the nonionic surfactant is an aminoglycoside compound. Studies have found that the ternary synergistic system formed by benzotriazole, lactitol, and aminoglycoside can effectively suppress the problem of ion precipitation in a plasma cutting environment;

[0030] (4) The coolant for the plasma cutting system provided by the present invention preferably contains a mixture of glutaraldehyde and cinnamaldehyde as the bactericide, which can produce an excellent bactericidal synergistic effect and can prevent the appearance of microorganisms in the coolant during long-term use in a high-temperature plasma environment;

[0031] (5) The coolant for plasma cutting system provided by the present invention is superior to the international advanced coolant level in preventing metal corrosion and maintaining low electrical conductivity. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions shall be followed.

[0033] In the following examples, the organosilicon defoaming agent used is from Dow Chemical.

[0034] Example 1

[0035] The composition and content of the plasma cutting coolant are as follows: 50 wt% of diol, 0.2 wt% of benzotriazole, 0.1 wt% of lactitol, 0.1 wt% of acamylamine, 0.05 wt% of glutaraldehyde, 0.05 wt% of cinnamaldehyde, 0.01 wt% of silicone defoaming agent, and the balance is ultrapure water.

[0036] First, add diol and ultrapure water into a preparation kettle and mix them evenly. Then, pass the diol aqueous solution through an anion and cation mixed bed exchange resin purification column. Then, add benzotriazole, lactitol, acamylamine, glutaraldehyde, cinnamaldehyde, and silicone defoamer into the preparation kettle in sequence. After stirring at 60° C. for 30 minutes to completely dissolve, cool the mixture to obtain the plasma cutting coolant of this embodiment.

[0037] Conductivity was tested using a conductivity meter. Aluminum sheets (3A21, 5A05, 6063, and brazing sheets) were connected, separated by a polytetrafluoroethylene gasket. The test sheets were then immersed in the plasma cutting coolant of the present invention and placed in an 80°C oven. After immersion for 168 hours, the conductivity was retested using a conductivity meter.

[0038] Example 2

[0039] The composition and content of the plasma cutting coolant are as follows: 50 wt% of diol, 0.2 wt% of benzotriazole, 0.1 wt% of lactitol, 0.1 wt% of acamylamine, 0.1 wt% of glutaraldehyde, 0.1 wt% of cinnamaldehyde, 0.01 wt% of silicone defoaming agent, and the balance is ultrapure water.

[0040] First, add diol and ultrapure water into a preparation kettle and mix them evenly. Then, pass the diol aqueous solution through an anion and cation mixed bed exchange resin purification column. Then, add benzotriazole, lactitol, acamylamine, glutaraldehyde, cinnamaldehyde, and silicone defoamer into the preparation kettle in sequence. After stirring at 60° C. for 30 minutes to completely dissolve, cool the mixture to obtain the plasma cutting coolant of this embodiment.

[0041] The conductivity was tested using a conductivity meter. 316L stainless steel was immersed in the plasma cutting coolant of this embodiment and placed in an 80° C. oven. After immersion for 168 hours, the conductivity was retested using a conductivity meter.

[0042] Example 3

[0043] The composition and content of the plasma cutting coolant are as follows: 50 wt% of diol, 0.2 wt% of benzotriazole, 0.1 wt% of lactitol, 0.1 wt% of acamylamine, 0.1 wt% of glutaraldehyde, 0.1 wt% of cinnamaldehyde, 0.01 wt% of silicone defoaming agent, and the balance is ultrapure water.

[0044] First, add diol and ultrapure water into a preparation kettle and mix them evenly. Then, pass the diol aqueous solution through an anion and cation mixed bed exchange resin purification column. Then, add benzotriazole, lactitol, acamylamine, glutaraldehyde, cinnamaldehyde, and silicone defoamer into the preparation kettle in sequence. After stirring at 60° C. for 30 minutes to completely dissolve, cool the mixture to obtain the plasma cutting coolant of this embodiment.

[0045] Conductivity was tested using a conductivity meter. One piece of brass and one piece of copper were connected together, separated by a polytetrafluoroethylene gasket. The pieces were immersed in the plasma cutting coolant of this embodiment and placed in an 80°C oven. After immersion for 168 hours, the conductivity was retested using a conductivity meter.

[0046] Example 4

[0047] The composition and content of the plasma cutting coolant are as follows: 50 wt% of diol, 0.2 wt% of benzotriazole, 0.1 wt% of lactitol, 0.1 wt% of acamylamine, 0.1 wt% of glutaraldehyde, 0.1 wt% of cinnamaldehyde, 0.01 wt% of silicone defoaming agent, and the balance is ultrapure water.

[0048] First, add diol and ultrapure water into a preparation kettle and mix them evenly. Then, pass the diol aqueous solution through an anion and cation mixed bed exchange resin purification column. Then, add benzotriazole, lactitol, acamylamine, glutaraldehyde, cinnamaldehyde, and silicone defoamer into the preparation kettle in sequence. After stirring at 60° C. for 30 minutes to completely dissolve, cool the mixture to obtain the plasma cutting coolant of this embodiment.

[0049] Conductivity was tested using a conductivity meter. Aluminum sheets (3A21, 5A05, 6063, 316L stainless steel, brass, copper, and brazing sheets) were connected, separated by Teflon washers. The test pieces were then immersed in the plasma cutting coolant used in this example and placed in an 80°C oven. After immersion for 168 hours, the conductivity was retested using a conductivity meter.

[0050] Comparative Example 1

[0051] A certain brand of automotive engine coolant.

[0052] Place automobile engine coolant in a Teflon reagent bottle and test its conductivity using a conductivity meter. Connect one piece each of 3A21 aluminum sheet, 5A05 aluminum sheet, 6063 aluminum sheet, 316L stainless steel sheet, brass sheet, copper sheet, and brazing sheet, separating them with Teflon washers. Then, immerse the test pieces in the automobile engine coolant and place them in an 80°C oven. After immersion for 168 hours, retest the conductivity using a conductivity meter.

[0053] Comparative Example 2

[0054] Ethylene glycol in water solution.

[0055] Place ethylene glycol in a polytetrafluoroethylene (PTFE) reagent bottle, then add ultrapure water in a 1:1 mass ratio to obtain the ethylene glycol aqueous solution of Comparative Example 2. Conductivity was tested using a conductivity meter. Connect one piece each of aluminum sheet 3A21, aluminum sheet 5A05, aluminum sheet 6063, 316L stainless steel, brass, copper, and a brazing sheet, separated by a polytetrafluoroethylene gasket. Then, immerse the test pieces in the ethylene glycol aqueous solution and place them in an 80°C oven. After immersion for 168 hours, retest the conductivity using a conductivity meter.

[0056] The comparison results are shown in Table 1.

[0057] Table 1

[0058]

[0059] As shown in Table 1, the conductivity of the plasma cutting system coolant provided by the present invention in Examples 1 to 4 remained less than 2 μS / cm after 168 hours. Under the same conditions, the conductivity of Comparative Examples 1 and 2 both exceeded 5 μS / cm, demonstrating that the plasma cutting system coolant provided by the present invention can maintain low conductivity.

[0060] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A coolant for a plasma cutting system, characterized in that: Calculated by mass percentage, it includes the following components:

2. The coolant for plasma cutting system according to claim 1, characterized in that: The diol is one of ethylene glycol, diethylene glycol, 1,2-propylene glycol, and 1,3-propylene glycol, or a mixture of two or more thereof.

3. The coolant for plasma cutting system according to claim 1 or 2, characterized in that: The corrosion inhibitor is one or a mixture of two or more of benzotriazole, 5-methylbenzotriazole and 5-aminobenzotriazole.

4. The coolant for plasma cutting system according to claim 1 or 2, characterized in that: The antioxidant is one or a mixture of two or more of inositol, quercetin, xylitol, erythritol, sorbitol, mannitol, lactitol, maltitol and isomalt.

5. The coolant for plasma cutting system according to claim 1 or 2, characterized in that: The nonionic surfactant is an aminoglycoside compound; preferably one or a mixture of two or more of acamicin, isopamicin, natilmicin, and gentamicin.

6. The coolant for plasma cutting system according to claim 1 or 2, characterized in that: The corrosion inhibitor is benzotriazole, the antioxidant is lactitol, and the nonionic surfactant is an aminoglycoside compound.

7. The coolant for plasma cutting system according to claim 1 or 2, characterized in that: The bactericide is a mixture of glutaraldehyde and cinnamaldehyde; preferably, the mass ratio of glutaraldehyde to cinnamaldehyde is 1:0.5-1.

5.

8. The coolant for plasma cutting system according to claim 1 or 2, characterized in that: The defoaming agent is one or a mixture of two or more of an organosilicon defoaming agent, a polyether defoaming agent and a polyether-modified organosilicon defoaming agent.

9. The coolant for plasma cutting system according to claim 1 or 2, characterized in that: It is composed of the following raw materials in percentage by mass:

10. The method for preparing a coolant for a plasma cutting system according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) mixing diol and deionized water to obtain a diol solution; (2) passing the diol solution through an anion and cation mixed bed exchange resin; (3) adding a corrosion inhibitor, an antioxidant, a nonionic surfactant, a bactericide, and a defoaming agent to the solution obtained in step (2), stirring until the solution is completely dissolved, and obtaining a coolant for a plasma cutting system.

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