Method for determining moisture content of gear oil

Abstract

The invention discloses a method for determining the moisture content of gear oil. The method comprises the following specific steps: acquiring a gas-phase initial moisture content value of dry gas; a to-be-detected gear oil sample and dry gas are mixed and oscillated in a sealed container to realize two-phase oscillation balance, the volume of the balanced to-be-detected gear oil sample and gas and the final moisture content value A of the gas are obtained, and the humidity increase value of the balanced dry gas is obtained; and obtaining the moisture content in the to-be-detected gear oil sample according to the humidity increase value, the balanced volumes of the to-be-detected gear oil sample and the gas, and the distribution coefficient of moisture in the to-be-detected gear oil sample and the gas. According to the method, the moisture content of the gear oil is calculated by utilizing gas-liquid two-phase balance of moisture in the closed container, a Karl's reagent is not needed, the detection method is simple, the cost is low, the method is harmless to human bodies, and the requirement for supervising the gear oil for wind power generation at present can be met.

Description

Technical Field

[0001] This invention belongs to the field of chemical analysis technology, specifically to a method for determining the moisture content of gear oil. Background Technology

[0002] Gear oil is mainly used for lubricating heavy-duty gears and bearings. Moisture content is a crucial control indicator in new oil acceptance and operational oil monitoring. With the rapid development of the wind power industry, a large quantity of operational gear oil requires monitoring for moisture content. Currently, coulometric and distillation methods are generally used to detect the moisture content in gear oil.

[0003] When using the coulometric method for testing, a Karl Fischer electrolyte is required. Due to the large quantity of wind turbine gear oil, the Karl Fischer electrolyte needs frequent replacement during testing. This electrolyte contains harmful organic compounds with a pungent odor; contact with it can harm the health of operators, causing symptoms such as limb spasms, dizziness, and coma. Furthermore, some components in the oil can contaminate the electrodes after entering the electrolytic cell, leading to inaccurate test results. Distillation methods, on the other hand, require large quantities of sample and organic solvent, are time-consuming, costly, and have low accuracy, failing to meet the current requirements for monitoring gear oils used in wind power generation. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for determining the moisture content of gear oil. The method calculates the moisture content of gear oil by utilizing the equilibrium of moisture in the gas and liquid phases in a closed container. It does not require Karl von Scheres' reagent, and the detection method is simple, low-cost, and harmless to the human body, which can meet the current needs for monitoring gear oil used in wind power generation. To achieve the above objectives, the present invention provides the following technical solution: a method for determining the moisture content of gear oil, the specific steps of which are as follows: S1 obtains the initial moisture content value of the gas phase of the dry gas. ; S2 involves mixing and agitating the gear oil sample and dry gas in a sealed container to allow moisture to reach equilibrium in the gas and liquid phases. The resulting equilibrium volumes of the gear oil sample and gas, the final moisture content A of the gas, and the increase in humidity of the dry gas after equilibrium are then determined. ; S3 calculates the moisture content in the gear oil sample based on the increase in humidity, the volume of the gear oil sample and gas after equilibrium, and the distribution coefficient of moisture in the gear oil sample and gas.

[0005] Furthermore, in S2, the volume ratio of dry gas to oil sample is 30~60:1; during mixing and oscillation, the temperature is 40~60℃, and equilibrium is reached when the change in gas phase humidity within 10 minutes is no greater than 0.3℃.

[0006] Furthermore, in S2, the calculation of the moisture content in the gear oil sample to be tested is as follows: W=K (2) Where: W—moisture content in oil, mg / L; K—distribution coefficient of moisture in the gas and liquid phases after gas-liquid equilibrium; A—moisture content in the gas phase after gas-liquid equilibrium under experimental conditions, μg / L; A0—initial moisture content in the gas phase under experimental conditions, μg / L; —After equilibrium, the volume of the gas phase, mL; V 油 —After equilibration, the volume of the gear oil sample to be tested, mL.

[0007] Furthermore, in S2, the initial gas phase volume of the dry gas is obtained as follows: Based on the ideal gas law, the initial gas phase volume of the dry gas is... Converted to the volume of gas after equilibrium .

[0008] Furthermore, in S2, the initial volume of the gear oil sample to be tested is obtained. The volume of the gear oil sample to be tested is determined based on the oil's coefficient of thermal expansion. Converted to the volume of the gear oil sample to be tested after equilibrium. .

[0009] Furthermore, in S3, the allocation coefficient is calculated as follows: S3.1 Obtain the humidity value C1 of the dry gas; S3.2 Place the gear oil sample and dry gas in a sealed container, mix and shake to allow the moisture to reach the first two-phase equilibrium in the gas and liquid phases. Discharge the gas from the sealed container and obtain the humidity value C2. The increase in humidity of the gas after the first two-phase equilibrium is [value missing]. =(C2-C1) S3.3 Inject the same volume of dry gas into the sealed container of S3.2 and obtain the humidity value C3 of the dry gas. Under the same conditions, mix and vibrate to allow the moisture to reach a second two-phase equilibrium in the gas and liquid phases, obtaining the humidity value C4 of the gas. The increase in humidity of the gas after the second two-phase equilibrium is [value missing]. (C4-C3); S3.4 Obtain the increase in humidity of the gas after two equilibrations, and the volume of the gear oil sample and the gas after equilibration. Based on the distribution law and the principle of material balance, obtain the distribution coefficient of moisture in the gas and liquid phases when the moisture in this type of gear oil sample is in gas-liquid equilibrium.

[0010] Furthermore, in S3.4, when the moisture in the gear oil sample reaches equilibrium between the gas and liquid phases, the formula for calculating the distribution coefficient of moisture between the gas and liquid phases is as follows: K= (1) Where: K—the distribution coefficient of water after gas-liquid equilibrium under experimental conditions; —Increase in vapor phase moisture content after the first equilibration, in μg / L; —The increase in vapor phase moisture content after the second equilibration, in μg / L; —Gas volume under experimental conditions after equilibrium, in L; V l —The volume of liquid under the test conditions after equilibrium is reached, in L.

[0011] Furthermore, in S3.4, the volume of the dry gas before equilibrium is obtained. Based on the ideal gas law, the volume of the dry gas before equilibrium is... Converted to the volume of gas after equilibrium .

[0012] Furthermore, in S3, the volume of the gear oil sample before balancing is obtained. The volume of the gear oil sample before equilibrium was determined based on the oil's coefficient of thermal expansion. Converted to obtain the volume of the gear oil sample after equilibrium. .

[0013] Furthermore, the dry gas mentioned in S1 is the same dry gas as the dry gas in S3.1 and S3.3, and its humidity is below -60℃; the gear oil sample to be tested in S2 is the same type of gear oil as the gear oil sample in S3.2; the mixing and oscillation conditions in S2 are the same as the mixing and oscillation conditions in S3.2 and S3.3.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: This invention provides a method for determining the moisture content of gear oil. First, the humidity of a dry gas is measured. A certain volume of dry gas and the gear oil sample to be tested are placed in a sealed container. Through shaking, moisture is allowed to reach equilibrium between the gas and liquid phases. The humidity of the gas after equilibrium is measured, and the increase in humidity of the dry gas after equilibrium is obtained. Based on this increase and the partition coefficient of moisture in the gas and the gear oil sample, the moisture content of the oil sample can be calculated. This method eliminates the need for electrodes and electrolytes, avoiding electrode contamination by additives in the oil sample that could lead to inaccurate test results and protecting the health of operators during operation.

[0015] In this invention, when calculating the distribution coefficient of moisture in a gas and a gear oil sample to be tested, a certain volume of dry gas and a gear oil sample are placed in a sealed container and oscillated under the same conditions as the steps for detecting moisture content. After the moisture reaches equilibrium between the gas and liquid phases, the humidity of the gas after equilibrium is measured to obtain the increase in humidity of the dry gas after the first equilibrium. Then, the gas in the two-phase oscillation equilibrium device is discharged, and the same volume of dry gas as the first time is injected again. Under the same conditions, the moisture reaches equilibrium between the gas and liquid phases a second time. Based on the increase in humidity of the dry gas after the two equilibrations and the volumes of the gas and oil sample, the distribution coefficient of moisture for this type of oil under these conditions is calculated. Based on the distribution coefficient of moisture in the oil, the moisture content of all oils related to this type of oil can be obtained through the two-phase oscillation equilibrium method. This method achieves oil moisture testing without using electrolytes that are harmful to the health of operators and also facilitates the automation of the entire operation process. Attached Figure Description

[0016] Figure 1 Flowchart of the method for determining the moisture content of gear oil according to the present invention. Detailed Implementation

[0017] The present invention will be further described below with reference to specific embodiments.

[0018] like Figure 1 As shown, the present invention provides a method for determining the moisture content of gear oil, the specific steps of which are as follows: S1 obtains the partition coefficient K of moisture in the gas-liquid two-phase structure of the gear oil sample, as follows: S1.1 Obtain the volume of the dry gas. The humidity value C1 requires the humidity value of the dry gas to be below -60℃; S1.2 Obtain the volume of the gear oil sample. The gear oil sample and dry gas were mixed and vibrated in a sealed container to allow the moisture to reach the first two-phase equilibrium in the gas and liquid phases. The humidity value C2 of the gas was obtained, and the increase in humidity of the dry gas after the first two-phase equilibrium was [value missing]. =(C2-C1) After discharging the dry gas from the sealed container in step S1.3, repeat step S1.1 to obtain the volume of the dry gas. And humidity value C3, of which = ; S1.4 Inject the dry gas into a sealed container. Under the same conditions as S1.2, allow the moisture to reach a second two-phase equilibrium in both the gas and liquid phases, obtaining the humidity value C4 of the gas. The increase in humidity of the dry gas after the second two-phase equilibrium is [value missing]. (C4-C3); S1.5 Based on the distribution law, material balance principle, and the increase in water concentration in the dry gas after two equilibrations, as well as the volumes of the gas and oil samples, the distribution coefficient of water in this type of gear oil in gas-liquid equilibrium under these conditions is obtained: K= (1) Where: K—the distribution coefficient of water after gas-liquid equilibrium under experimental conditions; —Increase in vapor phase moisture content after the first equilibration, in μg / L; —The increase in vapor phase moisture content after the second equilibration, in μg / L; —The volume of gas under the experimental conditions after equilibrium is reached, in L; V l —The volume of liquid under the test conditions after equilibrium is reached, in L; Among them, the volume of the dry gas before equilibrium is determined based on the ideal gas law. The volume of dry gas after equilibrium conversion The volume of the gear oil sample before equilibrium was determined based on the coefficient of thermal expansion of the oil. Converted to obtain the volume of the gear oil sample after equilibrium. ; = (2) In the formula: —The volume of gas under the experimental conditions after equilibrium is reached, in L; T—Two-phase oscillation equilibrium test temperature, °C; t—Ambient temperature at intake, °C; —Inlet volume at room temperature, μg / L; = (3) In the formula: —After equilibrium, the volume of the oil sample under the test conditions, in mL; T—Two-phase oscillation equilibrium test temperature, °C; t—Ambient temperature at intake, °C; —The volume of oil sample entering the equilibrium system at room temperature, in mL; The coefficient of thermal expansion is calculated based on the test result of β=(V2-V1) / (V1×(T2-T1)), where V1 is the oil volume at temperature T1 and V2 is the oil volume at temperature T2. .0008 — Coefficient of thermal expansion of oil, 1 / ℃; S2 obtains the initial gas phase volume of the dry gas. Initial moisture content of the gas phase ; Under the test conditions of S1.2, the gear oil sample to be tested and the dry gas are mixed and vibrated in a sealed container to achieve two-phase oscillation equilibrium. The final moisture content value A of the dry gas phase is obtained as the increase in humidity of the dry gas after equilibrium. ; S3 calculates the moisture content of the gear oil sample based on the humidity increase value and moisture distribution coefficient: W=K (2) Where: W—moisture content in the oil, mg / L; K—Under experimental conditions, the distribution coefficient of water in the gas and liquid phases after gas-liquid equilibrium; A—Under the experimental conditions, the vapor phase moisture content after gas-liquid equilibrium, in μg / L; A0—Under the experimental conditions, the initial moisture content of the gas phase, in μg / L; —The volume of the gas phase after equilibrium, in mL; V 油 —After equilibration, the volume of the gear oil sample to be tested is mL; the initial volume of the gear oil sample to be tested is The volume of the gear oil sample to be tested is determined based on the oil's coefficient of thermal expansion. Converted to the volume of the gear oil sample to be tested after equilibrium. .

[0019] Preferably, in this invention, the gas with humidity below -60°C is used as the drying gas, the volume ratio of the drying gas to the oil sample is 30~60:1, the temperature is 40~60°C when oscillating to equilibrium, and equilibrium is reached when the change in gas phase humidity within 10 minutes is no greater than 0.3°C.

[0020] Preferably, for the same brand and model of gear oil sample, including new oil and running oil, the moisture content of the oil sample can be obtained by simply following step S2 to achieve a single equilibrium between the gas and liquid phases, testing and recording the moisture content of the gas phase.

[0021] Example 1 This invention provides a method for determining the moisture content of gear oil, the specific steps of which are as follows: S1 obtains the distribution coefficient K of water in the gas-liquid two-phase system in Sinopec WT-320 gear oil sample A, as follows: S1.1 Obtain the humidity value of the dry gas as 6 μg / L; S1.2 At room temperature (20℃), a gear oil sample with a volume ratio of 1:60 and dry gas were placed in a sealed container. Under experimental conditions of 60℃ and a humidity increase of 0.2℃ within 10 minutes of shaking, the moisture content in the gas and liquid phases reached its first two-phase equilibrium. The humidity value of the dry gas was obtained as 1908 μg / L. The humidity increase of the dry gas after the first two-phase equilibrium was... ; After S1.3, the dry gas in the sealed container is discharged, and S1.1 is repeated to obtain the humidity value of the dry gas as 5 μg / L; S1.4 The same volume of dry gas as in S1.2 is injected into the sealed container again. Under the above conditions, the moisture content reaches a second two-phase equilibrium in the gas and liquid phases, yielding a humidity value of 144 μg / L for the dry gas. The increase in humidity of the dry gas after the second two-phase equilibrium is [value missing]. ; S1.5 Based on the distribution law, material balance principle, and the increase in water concentration in the dry gas after two equilibrations, as well as the gas and oil sample volumes, under these conditions, according to the above formula for calculating the distribution coefficient, the distribution coefficient of water in this type of gear oil in gas-liquid equilibrium is 5.376. S2 obtains the initial moisture content value of the gas phase of the dry gas. Under the test conditions of S1.2, 11.8 mL of Sinopec WT-320 gear oil sample A and dry gas were mixed and oscillated in a sealed container to achieve two-phase oscillation equilibrium. The final moisture content value of the dry gas phase was obtained as 1908. The increase in humidity of the dry gas after equilibrium was obtained. ; S3 calculated the moisture content of the gear oil sample to be 140% using the method described above. : S4 obtains the initial moisture content value of the gas phase of the dry gas. Under the test conditions of S1.2, another 11.8 mL sample of Sinopec WT-320 gear oil of the same brand, B, and dry gas were mixed and vibrated in a sealed container to achieve two-phase oscillation equilibrium. The final moisture content value of the dry gas phase was obtained as 1537. The increase in humidity of the dry gas after equilibrium was obtained. ; S3 calculated the moisture content of the gear oil sample to be 113% using the method described above. : Example 2: S1 obtains the distribution coefficient K of water in the gas-liquid two-phase system in Sinopec WT-320 gear oil sample A, as follows: S1.1 Obtain the humidity value of the dry gas as 5 μg / L; At room temperature (20℃), a gear oil sample with a volume ratio of 1:30 and dry gas were placed in a sealed container. Under experimental conditions of 60℃ and a humidity increase of 0.2℃ within 10 minutes of shaking, the moisture content in the gas and liquid phases reached its first two-phase equilibrium. The humidity value of the dry gas was obtained as 2538 μg / L. The humidity increase of the dry gas after the first two-phase equilibrium was [value missing].

[0022] After S1.3, the dry gas in the sealed container is discharged, and S1.1 is repeated to obtain the humidity value of the dry gas as 5 μg / L; S1.4 The same volume of dry gas as in S1.2 is injected into the sealed container again. Under the above conditions, the moisture content reaches a second two-phase equilibrium in the gas and liquid phases, resulting in a humidity value of 990 μg / L for the dry gas. The increase in humidity of the dry gas after the second two-phase equilibrium is [value missing]. ; S1.5 Based on the distribution law, material balance principle, and the increase in water concentration in the dry gas after two equilibrations, as well as the gas and oil sample volumes, under these conditions, according to the above formula for calculating the distribution coefficient, the distribution coefficient of water in this type of gear oil in gas-liquid equilibrium is 21.694. S2 obtains the initial moisture content value of the gas phase of the dry gas. Under the test conditions of S1.2, 11.8 mL of Sinopec WT-320 gear oil sample A and dry gas were mixed and vibrated in a sealed container to achieve two-phase oscillation equilibrium. The final moisture content value of the dry gas phase was obtained as 2538. The increase in humidity of the dry gas after equilibrium was obtained. ; S3, based on the above method for calculating the water content in oil products, determined the water content in the gear oil sample to be 141%. : S4 obtains the initial moisture content value of the gas phase of the dry gas. Under the test conditions of S1.2, another 11.8 mL sample of Sinopec WT-320 gear oil of the same brand, B, and dry gas were mixed and vibrated in a sealed container to achieve two-phase oscillation equilibrium. The final moisture content value of the dry gas phase was obtained. The increase in humidity of the dry gas after equilibrium was obtained. ; S5, calculated using the above method for determining moisture content in oil products, found the moisture content in the gear oil sample to be 111%. .

[0023] Example 3 S1 obtains the distribution coefficient K of moisture in the gas-liquid two-phase system in Mobil SHC XMP 320 gear oil sample A, as follows: S1.1 Obtain the humidity value of the dry gas as 6 μg / L; S1.2 At room temperature (20℃), a gear oil sample with a volume ratio of 1:60 and dry gas were placed in a sealed container. Under experimental conditions of 40℃ and a humidity increase of 0.3℃ within 10 minutes of shaking, the moisture content in the gas and liquid phases reached its first two-phase equilibrium. The humidity value of the dry gas was obtained as 396 μg / L. The humidity increase of the dry gas after the first two-phase equilibrium was... ; After S1.3, the dry gas in the sealed container is discharged, and S1.1 is repeated to obtain the humidity value of the dry gas as 5 μg / L; S1.4 The same volume of dry gas as in S1.2 is injected into the sealed container again. Under the above conditions, the moisture content reaches a second two-phase equilibrium in the gas and liquid phases, resulting in a humidity value of 156 μg / L for the dry gas. The increase in humidity of the dry gas after the second two-phase equilibrium is [value missing]. ; S1.5 Based on the distribution law, material balance principle, and the increase in water concentration in the dry gas after two equilibrations, as well as the volumes of the gas and oil samples, under these conditions, according to the above formula for calculating the distribution coefficient, the distribution coefficient of water in this type of gear oil in gas-liquid equilibrium is 40.496. S2 obtains the initial moisture content value of the gas phase of the dry gas. Under the experimental conditions of S1.2, 11.8 mL of Mobil SHC XMP 320 gear oil sample A and dry gas were mixed and vibrated in a sealed container to achieve two-phase oscillation equilibrium. The final moisture content value of the dry gas phase was obtained as 396. The increase in humidity of the dry gas after equilibrium was obtained. ; S3 calculated the moisture content of the gear oil sample to be 41% using the method described above. : S4 obtains the initial moisture content value of the gas phase of the dry gas. Under the test conditions of S1.2, another sample B of the same brand Mobil SHC XMP 320 gear oil (11.8 mL) and dry gas were mixed and shaken in a sealed container to achieve two-phase oscillation equilibrium. The final moisture content value of the dry gas phase was obtained as 680. The increase in humidity of the dry gas after equilibrium was obtained. ; S5, calculated using the aforementioned method for determining water content in oil products, found the water content in the gear oil sample to be 70%. : Example 4: S1 obtains the distribution coefficient K of moisture in the gas-liquid two-phase system in Mobil SHC XMP 320 gear oil sample A, as follows: S1.1 Obtain the humidity value of the dry gas as 6 μg / L; S1.2 At room temperature (20℃), a gear oil sample with a volume ratio of 1:30 and dry gas were placed in a sealed container. Under experimental conditions of 40℃ and a humidity increase of 0.3℃ within 10 minutes of shaking, the moisture content in the gas and liquid phases reached its first two-phase equilibrium. The humidity value of the dry gas was obtained as 294 μg / L. The humidity increase of the dry gas after the first two-phase equilibrium was... ; After S1.3, the dry gas in the sealed container is discharged, and S1.1 is repeated to obtain the humidity value of the dry gas as 8 μg / L; S1.4 The same volume of dry gas as in S1.2 is injected into the sealed container again. Under the above conditions, the moisture content reaches a second two-phase equilibrium in the gas and liquid phases, yielding a humidity value of 223 μg / L for the dry gas. The increase in humidity of the dry gas after the second two-phase equilibrium is [value missing]. ; S1.5 Based on the distribution law, material balance principle, and the increase in water concentration in the dry gas after two equilibrations, as well as the volumes of the gas and oil samples, under these conditions, the distribution coefficient of water in this type of gear oil in gas-liquid equilibrium, calculated using the above formula, is 94.346. S2 obtains the initial moisture content value of the gas phase of the dry gas. Under the test conditions of S1.2, 11.8 mL of the gear oil sample (A) and dry gas were mixed and vibrated in a sealed container to achieve two-phase oscillation equilibrium. The final moisture content value of the dry gas phase was obtained as 294. The increase in humidity of the dry gas after equilibrium was obtained. ; S3, based on the above method for calculating the water content in oil products, determined the water content in the gear oil sample to be 36%. : S4 obtains the initial moisture content value of the gas phase of the dry gas. Under the test conditions of S1.2, another sample B of the same brand Mobil SHC XMP 320 gear oil (11.8 mL) and dry gas were mixed and shaken in a sealed container to achieve two-phase oscillation equilibrium. The final moisture content value of the dry gas phase was obtained as 522. The increase in humidity of the dry gas after equilibrium was obtained. ; S5, calculated using the aforementioned method for determining water content in oil products, found the water content in the gear oil sample to be 65%. .

[0024] The average value of the moisture content of the same sample under different conditions in the examples was calculated and rounded to the nearest integer, as shown in the table below:

[0025] In summary, the detection method of this invention does not use organic solvents or electrolytes, thus avoiding safety hazards and harm to the health of operators. Moreover, the detection results are not significantly different from those of the coulometric method, and the detection results are relatively accurate. At the same time, it avoids the problem of sample contamination affecting the accuracy of the measurement results in the coulometric method.

Claims

1. A method for determining the moisture content of gear oil, characterized in that, The specific steps are as follows: S1 obtains the initial moisture content value of the gas phase of the dry gas. ; S2 involves mixing and agitating the gear oil sample and dry gas in a sealed container to allow moisture to reach equilibrium in the gas and liquid phases. The resulting equilibrium volumes of the gear oil sample and gas, the final moisture content A of the gas, and the increase in humidity of the dry gas after equilibrium are then determined. ; S3 calculates the moisture content in the gear oil sample based on the increase in humidity, the volume of the gear oil sample and gas after equilibrium, and the distribution coefficient of moisture in the gear oil sample and gas.

2. The method for determining the moisture content of gear oil according to claim 1, characterized in that, In S2, the volume ratio of dry gas to oil sample is 30~60:1; during mixing and oscillation, the temperature is 40~60℃, and equilibrium is reached when the change in gas phase humidity within 10 minutes is no greater than 0.3℃.

3. The method for determining the moisture content of gear oil according to claim 1, characterized in that, In S2, the calculation of the moisture content in the gear oil sample to be tested is as follows: W=K (2) Where: W—moisture content in oil, mg / L; K—distribution coefficient of moisture in the gas and liquid phases after gas-liquid equilibrium; A—moisture content in the gas phase after gas-liquid equilibrium under experimental conditions, μg / L; A0—initial moisture content in the gas phase under experimental conditions, μg / L; —After equilibrium, the volume of the gas phase, mL; V 油 —After equilibration, the volume of the gear oil sample to be tested, mL.

4. A method for determining the moisture content of gear oil according to claim 1 or 3, characterized in that, In S2, the initial gas phase volume of the dry gas is obtained as follows: Based on the ideal gas law, the initial gas phase volume of the dry gas is... Converted to the volume of gas after equilibrium .

5. A method for determining the moisture content of gear oil according to claim 1 or 3, characterized in that, In S2, the initial volume of the gear oil sample to be tested is obtained. The volume of the gear oil sample to be tested is determined based on the oil's coefficient of thermal expansion. Converted to the volume of the gear oil sample to be tested after equilibrium. .

6. The method for determining the moisture content of gear oil according to claim 1, characterized in that, In S3, the allocation coefficient is calculated as follows: S3.1 Obtain the humidity value C1 of the dry gas; S3.2 Place the gear oil sample and dry gas in a sealed container, mix and shake to allow the moisture to reach the first two-phase equilibrium between the gas and liquid phases. Discharge the gas from the sealed container and obtain the humidity value C2. The increase in humidity of the gas after the first two-phase equilibrium is [value missing]. =(C2-C1) S3.3 Inject the same volume of dry gas into the sealed container of S3.2 and obtain the humidity value C3 of the dry gas. Under the same conditions, mix and vibrate to allow the moisture to reach a second two-phase equilibrium in the gas and liquid phases, obtaining the humidity value C4 of the gas. The increase in humidity of the gas after the second two-phase equilibrium is [value missing]. (C4-C3); S3.4 Obtain the increase in humidity of the gas after two equilibrations, and the volume of the gear oil sample and the gas after equilibration. Based on the distribution law and the principle of material balance, obtain the distribution coefficient of moisture in the gas and liquid phases when the moisture in this type of gear oil sample is in gas-liquid equilibrium.

7. The method for determining the moisture content of gear oil according to claim 6, characterized in that, In S3.4, when the moisture in the gear oil sample reaches equilibrium between the gas and liquid phases, the formula for calculating the distribution coefficient of moisture in the gas and liquid phases is as follows: K= （1） Where: K—the distribution coefficient of water after gas-liquid equilibrium under experimental conditions; —Increase in vapor phase moisture content after the first equilibration, in μg / L; —The increase in vapor phase moisture content after the second equilibration, in μg / L; —Gas volume under experimental conditions after equilibrium, in L; V l —The volume of liquid under the test conditions after equilibrium is reached, in L.

8. A method for determining the moisture content of gear oil according to claim 6 or 7, characterized in that, In S3.4, obtain the volume of the dry gas before equilibrium. Based on the ideal gas law, the volume of the dry gas before equilibrium is... Converted to the volume of gas after equilibrium .

9. A method for determining the moisture content of gear oil according to claim 6 or 7, characterized in that, In S3, the volume of the gear oil sample before balancing is obtained. The volume of the gear oil sample before equilibrium was determined based on the oil's coefficient of thermal expansion. Converted to obtain the volume of the gear oil sample after equilibrium. .

10. The method for determining the moisture content of gear oil according to claim 6, characterized in that, The dry gas mentioned in S1 is the same as the dry gas mentioned in S3.1 and S3.3, and its humidity is below -60℃; the gear oil sample to be tested mentioned in S2 is the same type of gear oil as the gear oil sample mentioned in S3.2; the mixing and oscillation conditions mentioned in S2 are the same as the mixing and oscillation conditions mentioned in S3.2 and S3.3.

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