Determination method and detection equipment for content of base oil of lubricating grease

Abstract

The invention relates to the technical field of lubricating grease detection, and provides a method and equipment for measuring the content of base oil of lubricating grease. According to the method, the base oil in the lubricating grease is dissolved by adopting the solvent, then the solvent in the obtained base oil solution is removed to obtain the base oil, and the content of the base oil in the lubricating grease can be directly obtained by calculating according to the weight of the base oil and the weight of the lubricating grease. The standard method for directly detecting the content of the lubricating grease base oil is formulated, the detection result is accurate and reliable, and the recovery rate is high; moreover, the method can also be used for quantitatively detecting the base oil content of new lubricating grease and the base oil content of in-use lubricating grease, and the loss content of the base oil of the in-use lubricating grease is obtained through comparison, so that an effective basis is provided for model selection and service life prediction of the lubricating grease. The detection equipment provided by the invention integrates the functions of magnetic stirring, constant temperature, rotary separation, air exchange and organic solvent adsorption and the like, and can reduce environmental pollution and suction of an operator to the organic solvent.

Description

Technical Field

[0001] This invention relates to the field of grease testing technology, and in particular to a method and testing equipment for determining the base oil content of grease. Background Technology

[0002] Grease is an important lubricating material in industries such as industry, transportation, cement, and coal mining. It has a wide range of uses, not only for mechanical lubrication but also for sealing and protection.

[0003] Lubricating greases mainly consist of three parts: thickener, base oil, and additives (including enhancers and fillers), belonging to a two-phase dispersion system with a structural framework. The base oil acts as the dispersion medium, losing its fluidity after being encapsulated by the structural framework formed by the thickener, making the entire system semi-solid at room temperature. Most lubricating greases contain 70%–80% base oil, with some reaching as high as 95%. The base oil content directly affects the thickener's ability to encapsulate the base oil within the structural framework: if the base oil content is too high, exceeding the thickener's oil-holding limit, excessive oil separation can occur during storage or use, compromising system stability; if the base oil content is too low, the grease will have excessive viscosity, losing its lubricating properties, and may also reduce stability during storage due to structural imbalance. Therefore, throughout the entire life cycle of a lubricating grease, the base oil content is a key parameter for controlling and evaluating its stability and storage stability. However, there are currently no standard methods for testing the base oil content of lubricating greases, either domestically or internationally. Existing technologies often obtain base oil through methods such as steel mesh separation, pressure separation, and storage separation. However, these methods only reveal the stability and storage stability of the lubricating grease base oil, and cannot accurately determine the base oil content. In the field of railway lubricating greases, the "SH / T0319 Determination of Soap Content in Lubricating Greases" method is used. This method indirectly estimates the base oil content by measuring the soap content. However, this indirect calculation method is easily affected by the accuracy of soap content determination and interference from other components in the lubricating grease, leading to significant deviations in the test results. Summary of the Invention

[0004] In view of this, the present invention provides a method and testing equipment for determining the base oil content of lubricating grease. The determination method provided by the present invention can directly determine the base oil content in lubricating grease, and is simple to operate with high accuracy of test results.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A method for determining the base oil content of a lubricating grease includes the following steps: The lubricating grease is dissolved in a solvent and then subjected to solid-liquid separation to obtain a base oil solution and a precipitate; the solvent includes one or more of toluene, petroleum ether I, petroleum ether II, petroleum ether III, gasoline, and kerosene; The solvent is removed from the base oil solution to obtain the base oil; The content of base oil in the grease is calculated based on the weight of the base oil and the weight of the grease.

[0006] Preferably, the ratio of the lubricating grease to the solvent is 1g:6~10mL.

[0007] Preferably, the dissolution includes: stirring the grease and solvent evenly and then allowing it to stand at a constant temperature; the stirring speed is 100~800 r / min and the stirring time is 10~30 min; the constant temperature standing temperature is 20~30℃ and the time is 30~60 min.

[0008] Preferably, the solid-liquid separation is carried out under centrifugation conditions, the centrifugation speed is 1200~1700 r / min, and the time is 20~40 min; after centrifugation, the supernatant is filtered through qualitative filter paper to obtain the base oil solution.

[0009] Preferably, after the solid-liquid separation, the precipitate is washed with the solvent to obtain a washing liquid; the washing liquid and the liquid obtained from the solid-liquid separation are combined as a base oil solution.

[0010] Preferably, the method for removing solvent from the base oil solution includes: heating the base oil solution to evaporate the solvent and then drying it to a constant weight.

[0011] Preferably, the temperature for heating and evaporating the solvent is 110±3℃~140±3℃, and the time is 50~70min.

[0012] Preferably, the drying temperature is 100±1℃~110±1℃; the standard for drying to constant weight is: the weight difference between two consecutive weighings is not greater than 0.0005g.

[0013] The present invention also provides a detection device used in the determination method described above, comprising: An explosion-proof enclosure; the enclosure wall is provided with an air inlet, an air outlet, and a control panel; the air outlet is connected to an air pump; a filter is provided at the outlet of the air pump; a temperature control device and a motor are provided inside the explosion-proof enclosure; A rotating shaft; the rotating shaft is disposed inside the explosion-proof enclosure; the rotating shaft rotates under the drive of a motor; A magnetic stirring device; the magnetic stirring device is arranged around the rotating shaft and is fixedly connected to the rotating shaft by a support rod; Separator tube holder; the separator tube holder is installed on the magnetic stirring device.

[0014] Preferably, the number of magnetic stirring devices is four.

[0015] This invention provides a method for determining the base oil content of lubricating grease, comprising the following steps: dissolving the lubricating grease in a solvent and then performing solid-liquid separation to obtain a base oil solution and a precipitate; the solvent includes one or more of toluene, petroleum ether I, petroleum ether II, petroleum ether III, gasoline, and kerosene; removing the solvent from the base oil solution to obtain the base oil; and calculating the base oil content in the lubricating grease based on the weight of the base oil and the weight of the lubricating grease. This invention uses a solvent to dissolve the base oil in the lubricating grease, while additives and thickeners enter the precipitate. The solvent is then removed from the resulting base oil solution to obtain the base oil. The base oil content in the lubricating grease can be directly calculated based on the weight of the obtained base oil and the weight of the lubricating grease. This invention establishes a standard method for directly detecting the base oil content of lubricating grease. The test results are accurate and reliable, with a high recovery rate (99%~101%), providing reliable data support for the precise control of lubricating grease stability and storage stability. Furthermore, the method of this invention can also be used to quantitatively detect the base oil content of new lubricating grease and lubricating grease in use. By comparing the base oil loss content of lubricating grease in use, an effective basis can be provided for the selection of lubricating grease and the prediction of its service life.

[0016] This invention also provides a detection device used in the above-described determination method. The detection device provided by this invention integrates functions such as magnetic stirring, temperature control, rotary separation, and air exchange for organic solvent adsorption. It can automatically mix lubricating grease and solvent uniformly using magnetic stirring in a sealed, explosion-proof environment. After uniform mixing, it automatically enters a temperature control state. After temperature control, it performs high-speed rotary separation of the base oil solution and precipitates. After separation, the device innovatively utilizes an air exchange function to adsorb organic solvents, reducing environmental pollution and operator inhalation of organic solvents. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the detection device provided by the present invention, wherein the left side is a top view and the right side is a side view; Figure 1 In the middle: 1-rotating shaft, 2-magnetic stirring device, 3-separation tube clamping, 4-explosion-proof box, 5-air pump, 6-air inlet, 7-thermostat, 8-air outlet, 9-control panel, 10-motor; Figure 2 This is a flowchart of the experiment in Example 1; Figure 3 The diagram shows the effects of each experimental procedure in Example 1; Figure 4 The temperature changes of the petroleum ether II mixture under different heating times are shown. Detailed Implementation

[0018] This invention provides a method for determining the base oil content of lubricating grease, comprising the following steps: The lubricating grease is dissolved in a solvent and then subjected to solid-liquid separation to obtain a base oil solution and a precipitate; the solvent includes one or more of toluene, petroleum ether I, petroleum ether II, petroleum ether III, gasoline, and kerosene; The solvent is removed from the base oil solution to obtain the base oil; The content of base oil in the grease is calculated based on the weight of the base oil and the weight of the grease.

[0019] This invention involves dissolving lubricating grease in a solvent and then performing solid-liquid separation to obtain a base oil solution and a precipitate. In this invention, the solvent is one or more of toluene, petroleum ether I, petroleum ether II, petroleum ether III, gasoline, and kerosene, more preferably petroleum ether II; petroleum ether I is a petroleum ether with a boiling range of 30-60°C, petroleum ether II is a petroleum ether with a boiling range of 60-90°C, and petroleum ether III is a petroleum ether with a boiling range of 90-120°C. The solvents used in this invention can dissolve the base oil in the lubricating grease, while additives, thickeners, etc., remain insoluble, thereby achieving the extraction of the base oil from the lubricating grease.

[0020] In this invention, the preferred ratio of lubricating grease to solvent is 1g:6~10mL, specifically 1g:6mL, 1g:8mL, or 1g:10mL, preferably 1g:8mL. In a specific embodiment of this invention, the weight of the lubricating grease is denoted as m.

[0021] In this invention, the dissolution includes: stirring the grease and solvent evenly and then allowing them to stand at a constant temperature; the stirring speed is 100~800 r / min, and the stirring time is 10~30 min; the constant temperature standing temperature is 20~30℃, and the time is 30~60 min. In a specific embodiment of this invention, the stirring time is sufficient to ensure that the grease and solvent are completely and evenly mixed; during the constant temperature standing process, the evenly stirred liquid separates into layers, with the base oil dissolving in the solvent and undissolved thickeners and other additives precipitating. In this invention, the stirring is preferably magnetic stirring; in a specific embodiment of this invention, a stir bar for magnetic stirring is added to the separation tube, and during subsequent centrifugation, the stir bar and the precipitate settle together at the bottom of the separation tube.

[0022] In this invention, the solid-liquid separation is preferably carried out under centrifugal conditions. The centrifugal rotation speed is preferably 1200~1700 r / min, specifically 1200 r / min, 1500 r / min, or 1700 r / min, more preferably 1500 r / min; the centrifugation time is preferably 20~40 min, specifically 20 min, 30 min, or 40 min, more preferably 20 min. In a specific embodiment of this invention, the centrifugal separation is also carried out under constant temperature conditions, the constant temperature being the same as the temperature at which the mixture is kept at a constant temperature. After centrifugation, without stirring or dispersing the precipitate, the supernatant is poured through qualitative filter paper into a beaker dried to constant weight, and the weight of the beaker is recorded as m1. This invention, by controlling the centrifugal rotation speed and filtering the supernatant through qualitative filter paper, can effectively separate the base oil solution.

[0023] In a specific embodiment of the present invention, the grease and solvent are added to a separation tube, and then dissolved and centrifuged using the detection equipment designed in this invention, which will be described in detail later.

[0024] In this invention, after solid-liquid separation, the precipitate is washed with the solvent to obtain a washing liquid; the washing liquid and the liquid obtained from solid-liquid separation are combined as a base oil solution; the combined liquid is then subjected to subsequent solvent removal; the solvent used for washing is the same as the solvent used for dissolution, and will not be described in detail here; the washing is preferably performed 2 to 3 times; this invention washes the precipitate and combines the washing liquid and the supernatant obtained from centrifugation as a base oil solution, which can improve the accuracy of the detection results.

[0025] After obtaining the base oil solution, the present invention removes the solvent from the base oil solution to obtain the base oil. In the present invention, the method for removing the solvent from the base oil solution preferably includes: heating the base oil solution to evaporate the solvent and then drying it to constant weight; the temperature for heating and evaporating the solvent is preferably 110±3℃~140±3℃, specifically 110±3℃, 130±3℃, or 140±3℃; the time for heating and evaporating the solvent is preferably 50~70 min, specifically 50 min, 60 min, or 70 min. In a specific embodiment of the present invention, when the solvent is petroleum ether II, the temperature for heating and evaporating the solvent is preferably 130±3℃, and the time is preferably 60 min; the heating and evaporation of the solvent is preferably carried out on a heating plate; the present invention removes more than 98% of the solvent by heating and evaporating the solvent. In this invention, the drying temperature is preferably 100±1℃~110±1℃, specifically 105±1℃; the drying is based on drying to constant weight, and the standard for drying to constant weight is: the weight difference between two consecutive weighings is not greater than 0.0005g; in a specific embodiment of this invention, it is preferred to weigh once every 30 minutes of drying, and the drying is preferably carried out in an oven.

[0026] In this invention, after drying to constant weight, the solvent is considered to have been completely removed, and the remaining sample is the base oil. Preferably, the weight of the beaker containing the base oil is measured and denoted as m4, and then the base oil content in the grease is calculated using Formula I: Formula I; In Formula I: X1—base oil content, %; m4—weight of beaker and base oil, g; m1—weight of beaker, g; m—weight of grease sample, g.

[0027] The present invention also provides a detection device used in the determination method described above, comprising: Explosion-proof box 4; the explosion-proof box 4 is provided with an air inlet 6, an air outlet 8 and a control panel 9 on its wall; the air outlet 8 is connected to an air pump 5; a filter device is provided at the outlet of the air pump 5; the explosion-proof box 4 is provided with a temperature control device 7 and a motor 10. Rotating shaft 1; the rotating shaft 1 is disposed inside the explosion-proof box 4; the rotating shaft 1 rotates under the drive of motor 10; Magnetic stirring device 2; the magnetic stirring device 2 is arranged around the rotating shaft 1 and is fixedly connected to the rotating shaft 1 by a support rod; Separation tube holder 3; the separation tube holder 3 is set on the magnetic stirring device 2.

[0028] Figure 1 This is a schematic diagram of the detection device provided by the present invention, with the left side being a top view and the right side view. The following is in conjunction with... Figure 1 Please provide a detailed explanation.

[0029] In this invention, the air inlet 6 is an air inlet with a switch, and the air outlet 9 is an air outlet with a switch; the air inlet 6 and the air outlet 9 are preferably disposed on opposite walls of the explosion-proof box 4.

[0030] In this invention, the filtration device is preferably an activated carbon filter box.

[0031] In this invention, the adjustable speed of the rotating shaft is 100~2000 r / min.

[0032] In this invention, the adjustable stirring rate of the magnetic stirring device is 100~800 r / min; the number of magnetic stirring devices is preferably 4, which are fixedly connected to the rotating shaft by 4 support rods and rotate under the drive of the rotating shaft to achieve centrifugation; the 4 magnetic stirring devices are evenly distributed around the rotating shaft.

[0033] In this invention, each of the magnetic stirring devices is provided with a separation tube holder, and the number of holders on each separation tube holder is preferably 4, that is, 16 separation tubes can be placed in one detection device, which facilitates the simultaneous detection of multiple samples.

[0034] In this invention, the magnetic stirring device and the separation tube holder are both located inside the explosion-proof box, so that operations such as dissolving the grease and separating solids and liquids can be carried out under sealed and explosion-proof conditions.

[0035] In this invention, the operation of dissolution and solid-liquid separation using the aforementioned detection equipment specifically includes the following steps: placing the separation tube containing grease and solvent into the separation tube holder 3, adjusting the stirring rate of the magnetic stirring device 2, mixing the grease and solvent evenly under stirring conditions, and then using the constant temperature device 7 to bring the explosion-proof box into a constant temperature state, allowing the solution to separate into layers through constant temperature settling; after constant temperature settling, maintaining the constant temperature, adjusting the rotation speed of the rotating shaft 1 for centrifugal separation; after centrifugal separation, opening the air inlet 6, air outlet 8, and air pump 5 of the detection equipment to ventilate the detection equipment, thereby adsorbing organic solvents in the detection equipment, reducing the inhalation of operators and environmental pollution; then removing the separation tube and pouring out the supernatant in the separation tube.

[0036] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] Example 1 The experimental procedure in this embodiment is as follows: Figure 2 As shown, the specific testing steps are as follows: 1. Materials and reagents 1) Separation tube: conical, made of heat-resistant glass.

[0038] 2) Testing equipment: A schematic diagram of the testing equipment is shown below. Figure 1 As shown.

[0039] 3) Heating plate: can maintain a constant temperature of 130℃±3℃.

[0040] 5) Oven: Explosion-proof, forced-air oven, capable of maintaining a temperature of 105℃±3℃.

[0041] 6) Graduated cylinder: with graduations, capacity 50mL.

[0042] 7) Analytical balance: weighing accuracy is ±0.1mg.

[0043] 8) Beaker: graduated, with a capacity of 150mL.

[0044] 9) Scraper: made of metal, flat.

[0045] 10) Petroleum ethers I, II, and III: analytical grade, petroleum ether I (30-60℃), petroleum ether II (60-90℃), petroleum ether III (90-120℃).

[0046] 11) Toluene: analytical grade.

[0047] 12) Gasoline: analytical grade.

[0048] 13) Kerosene: analytical grade.

[0049] 2. Detection Methods and Procedures 1) After cleaning, place the separation tube in an oven at 105℃±3℃ and dry for 30 minutes. Take an appropriate amount of representative grease (the sample amount is about 5g) and add it to the separation tube. Add solvents (toluene, petroleum ether I, II, III, gasoline, and kerosene) to the separation tube, with the amounts being 30, 40, and 50 mL respectively.

[0050] 2) Place a clean 150mL beaker M1 in an oven at 105℃±3℃ and dry for 30min. Cool it in a desiccator and weigh it to the nearest 1mg.

[0051] 3) Place the separation tube into the separation tube slot of the testing equipment, adjust the stirring rate (800 r / min), and stir at a constant rate to ensure that the grease and solvent are completely and evenly mixed; adjust the rotation speed of the rotating head (select 1200 r / min, 1500 r / min, and 1700 r / min respectively), and separate for 20-40 minutes. After separation, turn on the ventilation adsorption function of the testing equipment to reduce the inhalation of organic solvents by operators and the pollution to the environment; finally, remove the separation tube and, without stirring or dispersing the precipitate, pour the supernatant (mixture of solvent and base oil) through qualitative filter paper into a constant-weight dry beaker M1. Wash the precipitate twice with solvent and combine the two washes into beaker M1.

[0052] 4) Place the beaker M1 containing the base oil solution on a constant temperature heating plate to remove most of the solvent and weigh the beaker as m2, accurate to 1 mg.

[0053] 5) Place beaker M1 in an oven at 100±3℃~110±3℃ and dry for 30 minutes. Cool it in a desiccator and weigh it m3, accurate to 1 mg.

[0054] 6) Repeat the test steps in step 5) until the difference between two consecutive weighings is no greater than 0.0005g. The solvent can be considered to have been removed. The remaining sample is the base oil. Weigh the beaker containing the base oil to the nearest 1mg and record it as m4.

[0055] The effect diagrams of each experimental procedure are as follows Figure 3 As shown ( Figure 3 The top images, from left to right, show the process of adding grease to the separation tube, dissolving the grease, and centrifuging. The bottom images, from left to right, show the process of filtering the supernatant, heating to evaporate the solvent, and drying.

[0056] 7) Calculation The base oil content in the grease can be calculated using Formula I: Equation I; In Equation I: X1 – Base oil content, % m4 — Weight of beaker and base oil, in grams; m1 — Weight of the beaker, in grams; m — Sample weight of grease, in grams.

[0057] 3. Test Results 1) Solvent type and amount added A grease sample with a base oil content of 75% was selected. The ratio of grease to solvent was 1g:6mL, 1g:8mL and 1g:10mL (5g of grease and 30, 40 and 50 mL of solvent were taken respectively). The experimental results are shown in Table 1 (the separation speed was fixed at 1500 r / min, the separation time was fixed at 20 min, the heating plate temperature was fixed at 130±3℃, the heating time of the heating plate was fixed at 60 min, and the oven temperature was fixed at 105±1℃).

[0058] Table 1. Experimental results of solvent and dosage.

[0059] As shown in Table 1, the extraction effect of base oil was optimal when petroleum ether II was used as the solvent and the ratio of lubricating grease to petroleum ether II was 1 g: 8 mL, and the obtained test results were closest to the actual results. Subsequent experiments were all conducted using petroleum ether II as the solvent.

[0060] 2) Separate rotation speed and time The grease sample used had a base oil content of 75%, and the solvent used in the test was petroleum ether II, with a grease-to-solvent ratio of 1 g:8 mL. The heating plate temperature was fixed at 130±3℃, the heating time was fixed at 60 min, and the oven temperature was fixed at 105±1℃. The separation speeds were 1200 r / min, 1500 r / min, and 1700 r / min, and the separation times were 20 min, 30 min, and 40 min, respectively. The test results of the base oil content obtained under different separation speeds and times are shown in Table 2.

[0061] Table 2 Experimental results at different separation speeds and times

[0062] The experimental results in Table 2 show that the test results are most accurate when the separation speed is 1500 r / min. The separation time has little effect on the difference in the test results. Based on the principle of energy conservation, the optimal separation time is 20 min.

[0063] 3) Optimal temperature and time for removing petroleum ether The grease sample used had a base oil content of 75%, and the solvent used in the test was petroleum ether II. 40 mL of petroleum ether II was selected for the experiment, with a grease-to-solvent ratio of 1 g:8 mL. The separation speed was 1500 r / min, and the separation time was 20 min. When removing petroleum ether II, the hot plate temperature was set at 110±3℃, 130±3℃, or 140±3℃, for 50 min, 60 min, or 70 min, respectively. The percentage of residual petroleum ether II in the total petroleum ether was measured, and the experimental results are shown in Table 3.

[0064] Table 3 Residual amount of petroleum ether II / %

[0065] Experimental results showed that the residue of petroleum ether II was low under conditions of 130℃±3℃ to 140℃±3℃. However, excessively high temperatures might affect the base oil, causing the volatilization of light components. Therefore, the optimal setting for the heating plate was 130℃±3℃ for 60 minutes. The temperature changes of the petroleum ether II mixture were recorded over 70 minutes during the experiment. Figure 4 As shown.

[0066] 4) Selection of drying temperature in the oven The grease sample used had a base oil content of 75%, and the solvent used in the test was petroleum ether II. 40 mL of petroleum ether II was selected for the test, with a grease-to-solvent ratio of 1 g:8 mL. The separation speed was 1500 r / min, and the separation time was 20 min. When removing petroleum ether II, the hot plate temperature was set at 130±3℃ for 60 min.

[0067] The oven temperatures were 100±1℃, 105±1℃, and 110±1℃, and the drying time for each cycle was 30 min. The experimental results are shown in Table 4.

[0068] Table 4 Test results under different drying conditions

[0069] Experimental results show that excessively high oven temperature can affect the base oil. The optimal oven temperature is 105℃±1℃, and the optimal difference between continuous constant weight weighings is no greater than 0.0005g.

[0070] 4. Spike Recovery Experiment Spike recovery experiments were conducted using the optimized experimental conditions described above, and the test results are shown in Table 5.

[0071] Table 5 Results of Spiked Recovery Experiment

[0072] Experimental results show that the recovery rate of the spiked recovery test is between 99% and 101%, and the results are accurate and reliable.

[0073] 5. Testing of new grease, in-use grease, and expired grease. Using the optimized experimental conditions described above, the base oil content of new No. 1 grease, in-use grease, and failed grease was tested to determine the base oil content of the in-use grease at the time of failure. Other relevant physicochemical indicators were also tested, and the base oil content and related physicochemical indicators were compared with standard values. The test results are shown in Table 6.

[0074] Table 6 Performance test results of No. 1 new grease, in-use grease, and depleted in-use grease

[0075] The experimental results in Table 6 show that the base oil content of the new No. 1 grease, the in-use grease, and the failed in-use grease gradually decreases. When the base oil content reaches a certain limit, it will lose its effectiveness. According to the data in Table 1, compared with the new No. 1 grease, the base oil content change rate of the in-use grease is 25.1%, and the base oil content change rate of the failed grease is 29%. For ease of operation, "the base oil content change rate is 25% of the recommended lower limit of the product" can be used as the criterion for judging whether the grease can not meet the usage requirements. After the grease fails, other physicochemical indicators such as appearance will become dull, working cone penetration, extended working cone penetration (100,000 cycles) and the difference between working cone penetration, stencil oil separation, anti-wear performance (four-ball machine method), extreme pressure performance sintering load, and similar viscosity will all fail to meet the standard value requirements.

[0076] In summary, the method provided by this invention enables direct detection of the base oil content in lubricating grease. Petroleum ether II is optimally selected as the extraction solvent, and the ratio of lubricating grease to petroleum ether II, separation speed, solvent removal temperature, and drying temperature are also optimized. A standard method for directly detecting the base oil content of lubricating grease has been established, with a good recovery rate (99%-101%) and reliable accuracy. Furthermore, this method can quantitatively detect the base oil content of new and used lubricating greases, allowing for comparison to determine the base oil loss in used greases, providing a valid basis for grease selection and life prediction. This invention also develops a detection device integrating magnetic stirring, temperature control, rotary separation, and ventilation adsorption of organic solvents. This device automatically mixes lubricating grease and solvent uniformly using magnetic stirring in a sealed, explosion-proof environment. After uniform mixing, it automatically enters a temperature control state, followed by high-speed rotary separation of the base oil solution and precipitates. After separation, the device's innovative ventilation function adsorbs organic solvents, reducing environmental pollution and operator inhalation of organic solvents.

[0077] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the base oil content of a lubricating grease, characterized in that, Includes the following steps: The lubricating grease is dissolved in a solvent and then subjected to solid-liquid separation to obtain a base oil solution and a precipitate; the solvent includes one or more of toluene, petroleum ether I, petroleum ether II, petroleum ether III, gasoline, and kerosene; The solvent is removed from the base oil solution to obtain the base oil; The content of base oil in the grease is calculated based on the weight of the base oil and the weight of the grease.

2. The determination method according to claim 1, characterized in that, The ratio of the lubricating grease to the solvent is 1g:6~10mL.

3. The determination method according to claim 1, characterized in that, The dissolution process includes: stirring the grease and solvent evenly and then allowing them to stand at a constant temperature; the stirring speed is 100~800 r / min and the stirring time is 10~30 min; the constant temperature standing temperature is 20~30℃ and the time is 30~60 min.

4. The determination method according to claim 1, characterized in that, The solid-liquid separation is carried out under centrifugation conditions, with a centrifugation speed of 1200~1700 r / min and a time of 20~40 min; after centrifugation, the supernatant is filtered through qualitative filter paper to obtain a base oil solution.

5. The determination method according to claim 1 or 4, characterized in that, After solid-liquid separation, the precipitate is washed with the solvent to obtain a washing liquid; the washing liquid and the liquid obtained from solid-liquid separation are combined as a base oil solution.

6. The determination method according to claim 1, characterized in that, The method for removing solvent from the base oil solution includes: heating the base oil solution to evaporate the solvent and then drying it to constant weight.

7. The determination method according to claim 6, characterized in that, The temperature for heating and evaporating the solvent is 110±3℃~140±3℃, and the time is 50~70min.

8. The determination method according to claim 6, characterized in that, The drying temperature is 100±1℃~110±1℃; the standard for drying to constant weight is: the weight difference between two consecutive weighings is not greater than 0.0005g.

9. The detection equipment used in the determination method according to any one of claims 1 to 8, characterized in that, include: An explosion-proof enclosure; the enclosure wall is provided with an air inlet, an air outlet, and a control panel; the air outlet is connected to an air pump; a filter is provided at the outlet of the air pump; a temperature control device and a motor are provided inside the explosion-proof enclosure; A rotating shaft; the rotating shaft is disposed inside the explosion-proof enclosure; the rotating shaft rotates under the drive of a motor; A magnetic stirring device; the magnetic stirring device is arranged around the rotating shaft and is fixedly connected to the rotating shaft by a support rod; Separator holder; the separator holder is installed on the magnetic stirring device.

10. The detection device according to claim 9, characterized in that, The number of magnetic stirring devices is 4.

Images