Aviation turbine lubricating oil thermal stability corrosion test ultimate vacuum device and method thereof

Abstract

The invention relates to the technical field of aviation oil product testing, and discloses an aviation turbine lubricating oil thermal stability corrosion test ultimate vacuum device and method, and the device comprises a vacuum pump, a vacuum gauge, a first control valve, a second control valve and a water bath pool which are arranged in sequence; a first vacuum pipe is connected between the vacuum pump and the vacuum gauge; a second vacuum pipe is connected between the vacuum gauge and the first control valve; a vacuum clamp is connected between the first control valve and the second control valve; the second control valve is communicated with the interior of the test tube through a third vacuum tube; the water bath pool is a constant-temperature water bath pool; the test tube comprises a capillary tube body and an oxidation tube body which are integrally connected; and the third vacuum tube is communicated with the capillary tube body. According to the invention, an ultimate vacuum environment can be constructed in the test tube, and the vacuum degree is high and can be stably maintained.

Description

Technical Field

[0001] The invention relates to the technical field of aviation oil testing, and in particular to an extreme vacuum device and method for thermal stability corrosion testing of aviation turbine lubricating oil. Background Art

[0002] In order to ensure the safe and efficient operation of aviation turbine engines, the lubrication system must continuously supply stable aviation turbine lubricating oil to the key friction parts of the engine. This lubricating oil can not only effectively reduce the friction and wear between components, but also efficiently conduct and remove the high temperature generated by fuel combustion, helping to maintain the engine within a suitable operating temperature range, thereby ensuring its long-term stable operation. Aviation turbine lubricating oil will undergo a series of dynamic changes such as heat absorption, temperature rise, chemical oxidation and subsequent cooling during its circulation. These processes may cause evaporation loss of lubricating oil, formation of carbon deposits or corrosion of metal surfaces. Therefore, aviation turbine lubricating oil must have high thermal stability, oxidation resistance and good chemical inertness to cope with extreme working conditions. To evaluate whether an aviation turbine lubricating oil meets the use requirements, it is usually necessary to conduct comprehensive testing and evaluation of multiple key performance indicators such as thermal stability, oxidation resistance, and corrosiveness based on international and industry standards.

[0003] However, there are currently few researchers or research institutions in China that can make accurate tests and evaluations of these key performance indicators, and there are many technical barriers. Take the thermal stability and corrosiveness performance index tests of aviation turbine lubricants as an example. In the internationally recognized airworthiness standards, both of these indicators need to be carried out in a specific vacuum environment to exclude the influence of air and simulate real working conditions. On the surface, vacuum conditions are not difficult to create. However, in the actual test environment, since the test conditions also include extreme high temperatures (close to 300°C), ultra-long continuous test cycles (96 hours or longer test cycles), and strict variable control, these factors have put forward more stringent requirements on vacuum conditions. If the vacuum purity is insufficient or cannot be maintained, it will directly affect the test quality and cause safety risks. Summary of the invention

[0004] The present invention aims to provide an extreme vacuum device and method for thermal stability corrosion test of aviation turbine lubricating oil, which can construct an extreme vacuum environment in a test tube with high vacuum degree and can be stably maintained.

[0005] To achieve the above objectives, the present invention provides the following basic solutions.

[0006] Solution 1 The extreme vacuum device for the thermal stability corrosion test of aviation turbine lubricating oil comprises a vacuum pump, a vacuum gauge, a first control valve, a second control valve and a water bath which are arranged in sequence; a first vacuum tube is connected between the vacuum pump and the vacuum gauge; a second vacuum tube is connected between the vacuum gauge and the first control valve; a vacuum clamp is connected between the first control valve and the second control valve; the second control valve is connected to the inside of the test tube through a third vacuum tube; the water bath is a constant temperature water bath; The test tube comprises a capillary body and an oxidation tube body which are integrally connected; the third vacuum tube is connected to the capillary body.

[0007] Furthermore, the first vacuum tube and the second vacuum tube are both high vacuum bellows; and the third vacuum tube is a thick-walled silicone tube.

[0008] Furthermore, the first control valve is a high vacuum ball valve; and the second control valve is a double pagoda head ball valve.

[0009] Furthermore, the temperature of the constant temperature water bath is set to 80°C±1°C.

[0010] Furthermore, the lengths of the first vacuum tube and the second vacuum tube are set to 100 cm±10 cm; and fastening rings are provided at both ends of the first vacuum tube and both ends of the second vacuum tube.

[0011] Solution 2 The method for using the extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil is to use the extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil as described in Scheme 1 to conduct the thermal stability corrosion test of aviation turbine lubricating oil; the method comprises the following steps: Step 1: Assemble the extreme vacuum device for the thermal stability corrosion test of aviation turbine lubricating oil; and pre-add the oil sample to be tested into the test tube; Step 2, tilting and standing the test tube; and turning on the vacuum pump, the first control valve and the second control valve, and observing the state of the oil sample in the test tube; if the state of the oil sample shows that no bubbles are generated within the first preset time, then executing the next step; otherwise, the test tube is determined to be a waste tube, and the test tube is replaced and this step is repeated until the state of the oil sample shows that no bubbles are generated within the first preset time; Step 3, start the constant temperature water bath and set its temperature to the target temperature, and place the test tube in the constant temperature water bath; Step 4, observe the vacuum gauge value, when the vacuum gauge value is lower than the reference value, close the second control valve, the first control valve, and the vacuum pump in sequence; Step 5, transferring the test tube and sealing the test tube at high temperature from the capillary tube; Step 6, determine the sealing state of the test tube, and after the sealing state meets the standard, transfer the test tube to a high temperature bath for performance testing.

[0012] Furthermore, in the second half of the first preset time, the test tube is kept being shaken; and, in the first preset time, if specific bubble characteristics appear, the test tube is directly determined to be a waste tube; the specific bubble characteristics include linear small bubbles; the small bubbles refer to bubbles with a diameter of 30μm~50μm.

[0013] Furthermore, in step 5, when the test tube is transferred, the second control valve and the third vacuum tube are transferred together.

[0014] Further, in step 5, the sealing position of the test tube is selected to be 5 cm to 8 cm away from the top of the tube mouth of the oxidation tube body; the width of the sealing position is set to 1 cm to 1.5 cm; the sealing thickness is set to 3 cm; and the sealing temperature of the high-temperature sealing is set to 820°C to 850°C.

[0015] Further, in step 6, the fusion sealing state meets the standard means that an inward concave feature appears at the fusion sealing opening, and the depth of the concave feature is 1.5 mm to 2 mm.

[0016] The working principle and advantages of the present invention are: The extreme vacuum device and method for the thermal stability corrosion test of aviation turbine lubricating oil of the present invention can construct an extreme vacuum environment in the test tube, and the vacuum degree is high and can be maintained stably. The key points are: This scheme uses existing devices to construct a new extreme vacuum device, and provides a new and more reliable vacuum condition construction path for aviation turbine lubricating oil thermal stability and corrosion test. First of all, the extreme vacuum device of this scheme is connected to the inside of the test tube one-to-one, which can achieve targeted vacuuming, accurately ensure that the vacuum degree in the test tube meets the standard and will not affect other test operations. Compared with the existing test vacuuming devices, such as the patent with publication number CN211577022U, which discloses an aviation turbine engine lubricating oil thermal stability and corrosion tester, the vacuum component used therein is to vacuum the entire environment of the test pool. Although this method is efficient, it has low accuracy and cannot guarantee that the vacuum degree in the test pool is absolutely up to standard, and it is impossible to accurately know the pressure in the test pool, and it is not convenient to perform subsequent test operations on the test pool.

[0017] This solution does not have such problems. More importantly, this solution can perfectly match the standard requirements to ensure that the subsequent test results have practical reference value. In the requirements of the aviation standard for the thermal stability and corrosion test of aviation turbine engine lubricants, for a completely sealed test tube, the internal absolute pressure is required to be less than 1.3pa to form a standard test environment, otherwise it will lead to test failure or the test results will be unreliable and uncredible - first, because aviation turbine lubricants need to maintain performance in a high-altitude, low-pressure environment in actual applications; second, if there is residual oxygen in the test tube (insufficient vacuum), in the thermal stability test, the lubricant will contact oxygen at high temperature and induce oxidation reaction, generating by-products such as carbon deposits and colloids. These reactions may mask the thermal decomposition characteristics of the oil itself, resulting in inaccurate results; in the corrosion test, it will make it difficult to fully eliminate the corrosion effect of environmental gases on the metal test piece and it is easy to increase complex side reactions, resulting in inaccurate results. The vacuum device provided by this solution can accurately measure and stably maintain the vacuum environment required by the standard, which helps to ensure that thermal stability and corrosion tests only reflect the behavior of the oil under pure thermodynamics or its own chemical properties, ensuring that the test results are reliable and credible.

[0018] Secondly, this solution optimizes the connection method and layout of each device, and can build a stable vacuum environment and a stable vacuum degree verification environment. The overall system construction method is simple, the structure setting is simple, and efficient vacuuming can be achieved. Among them, first, the selection of each device fits the high vacuum scene, has extremely high reliability and stability, and can meet the continuous vacuuming work requirements during the thermal stability corrosion test of aviation turbine lubricating oil. Second, the layout setting of each device is special. It is not simply connected to the vacuum pump with pipelines and valve bodies, but multi-level pipelines and multi-level valve bodies are set up in combination with vacuum gauges to build a stable vacuum route. Through the two-layer valve body setting, independent control, local isolation and double protection are achieved, and it is easy to independently split the test tube without affecting the test process. Through the setting of equal-length long corrugated pipes at both ends of the vacuum gauge, the stability and balance of the air pressure environment at both ends of the vacuum gauge are achieved, and the resistance of the vacuum gauge to external fluctuations can be enhanced, which helps to improve the measurement accuracy of the vacuum gauge and achieve absolutely accurate and reliable vacuum degree measurement.

[0019] Furthermore, the device structure of this solution supports partial dismantling, that is, supports the transfer of the second control valve and the third vacuum tube. In this way, the second control valve and the third vacuum tube can ensure that the test tube maintains a stable vacuum degree during the transfer process and the subsequent high-temperature sealing process.

[0020] Second, this solution fills the gap in the construction of vacuum conditions in the thermal stability corrosion test of aviation turbine lubricating oil, and can greatly improve the success rate and efficiency of the thermal stability corrosion test of aviation turbine lubricating oil. Compared with the existing test methods, such as the patent with publication number CN116754750A, which discloses a performance test device and method for aviation lubricating oil, although this solution provides complete test operation instructions, it does not provide specific vacuum operation instructions, and the vacuum effect cannot be confirmed. In addition, the vacuum method used will actually damage the subsequent sealing quality and cause the risk of pipe explosion (such as maintaining vacuum during sealing, which will interfere with the temperature distribution of the sealing position and easily form bubbles, affecting the uniformity and quality of the sealing).

[0021] This scheme provides detailed vacuuming guidance for the thermal stability corrosion test of aviation turbine lubricating oil, which can fully confirm the vacuuming effect and maintain the vacuum effect without affecting the quality of the seal. This scheme observes the state of the oil sample in stages, uses bubbles as a dominant feature to verify the gas environment in the test tube, can accurately determine the vacuum degree in the test tube, and promptly verify whether the air tightness of the tube body meets the requirements. While ensuring that the vacuum purity meets the standard, it helps to reduce the subsequent risk of tube explosion caused by the quality of the tube body or the quality of the seal (if the vacuum degree in the test tube cannot be maintained after being sealed, there is residual pressure or the pressure is released, it will cause the oxidation tube to burst, affecting the test process and causing safety risks). BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a schematic diagram of the structure of an extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil and a method embodiment thereof.

[0023] The symbols in the drawings of the specification include: test bench 1, vacuum pump 2, first vacuum tube 3, iron frame 4, vacuum gauge 5, metal tee 6, second vacuum tube 7, first control valve 8, second control valve 9, third vacuum tube 10, vacuum clamp 11, test tube 12, constant temperature water bath 13. DETAILED DESCRIPTION

[0024] The following is a further detailed description through specific implementation methods: The embodiment is basically as shown in the attached Figure 1 As shown: The extreme vacuum device for the thermal stability corrosion test of aviation turbine lubricating oil includes a vacuum pump 2, a vacuum gauge 5, a first control valve 8, a second control valve 9 and a water bath which are sequentially arranged on a test bench 1.

[0025] A first vacuum tube 3 is connected between the vacuum pump 2 and the vacuum gauge 5; a second vacuum tube 7 is connected between the vacuum gauge 5 and the first control valve 8; a vacuum clamp 11 is connected between the first control valve 8 and the second control valve 9; and the second control valve 9 is connected to the inside of the test tube 12 via a third vacuum tube 10.

[0026] The test tube 12 includes a capillary body and an oxidation tube body connected in one piece; the third vacuum tube 10 is connected to the capillary body. In this embodiment, the test tube 12 is made of borosilicate glass, which has a low expansion rate, good chemical corrosion resistance and thermal shock resistance, and can be adapted to the aviation oil test environment with a long test cycle and high temperature conditions.

[0027] Specifically, the vacuum pump 2 uses a two-stage rotary vane vacuum pump 2, whose pumping rate is not less than 4³ / h, the ultimate vacuum pressure is not higher than 0.05Pa, and has extremely high reliability and stability, which can meet the continuous vacuum working requirements during the thermal stability corrosion test of aviation turbine lubricating oil.

[0028] An iron frame 4 is also provided on the test bench 1, and the vacuum gauge 5 is installed on the iron frame 4 to keep its position stable. The vacuum gauge 5 is a digital vacuum gauge 5, and its measuring range is ~1 Pa, with an accuracy of up to 0.05 Pa. The vacuum gauge 5 can accurately measure the vacuum degree achieved by the device and display it visually, providing an objective and reliable reference for vacuum condition verification.

[0029] The first vacuum tube 3 and the second vacuum tube 7 are both high vacuum bellows; the third vacuum tube 10 is a thick-walled silicone tube, and the thickness of the thick-walled silicone tube is not less than 2 mm. The length of the first vacuum tube 3 and the second vacuum tube 7 is set to 100 cm ± 10 cm; and fastening rings are provided at both ends of the first vacuum tube 3 and the second vacuum tube 7 to further enhance the air tightness of the device. The fastening ring is a stainless steel vacuum clamp.

[0030] Among them, the high vacuum bellows is a flexible connector specially designed for use in a high vacuum environment. It is mainly used for pipe connections in vacuum systems to achieve relative movement between components or compensate for installation deviations. It has good sealing performance and strong corrosion resistance. The first vacuum tube 3 and the second vacuum tube 7 use this pipe to ensure that good airtightness can be maintained under extremely high vacuum conditions, prevent external gas infiltration or internal gas leakage, and can adapt to different working environments. The thick-walled silicone tube is a hose made of high-quality silicone rubber. It has good temperature resistance, corrosion resistance, softness and elasticity, and can cooperate well with the test tube 12.

[0031] Furthermore, in the present embodiment, the lengths of the first vacuum tube 3 and the second vacuum tube 7 are both set to 100 cm; this length design takes into special consideration the ergonomics during the test operation, so that the test personnel can stably hold the vacuum tube and the test tube 12 when subsequently transferring the test tube 12, and because the pipe length is moderate, the pipe is not prone to dragging during the transfer process, which helps to maintain the stability of the internal vacuum environment during the transfer of the test tube 12.

[0032] The first vacuum tube 3, the second vacuum tube 7 and the vacuum gauge 5 are connected by a metal tee 6. In addition, the first vacuum tube 3 and the second vacuum tube 7 of relatively equal length are connected to the two ends of the vacuum gauge 5. Firstly, the air pressure environment at both ends of the vacuum gauge 5 can be balanced and stabilized; secondly, the bellows have good vibration reduction performance and flexible buffering effect, which can relatively isolate the vacuum gauge 5 from the vacuum pump 2, balance the vibration, maintain the mechanical stability of the entire device, and help improve the measurement accuracy of the vacuum gauge 5; thirdly, the bellows of equal length at both ends can ensure that the gas flows more evenly when entering and leaving the vacuum gauge 5, reduce turbulence and eddy current phenomena, and improve the accuracy of measurement; fourthly, the flexibility and compressibility of the bellows help to maintain the pressure balance of the system under different pressure conditions and avoid measurement errors caused by pressure fluctuations; fifthly, the bellows of equal length can make installation more convenient, and can more easily adjust and calibrate the positions of various components to ensure the overall performance of the system.

[0033] The first control valve 8 is a high vacuum ball valve. In this embodiment, a KF16 stainless steel ball valve is selected, which is suitable for high vacuum environment and has extremely high sealing performance; the second control valve 9 is a double pagoda head ball valve, which has a good sealing effect, and pagoda joints are used at both ends. This type of joint is easy and quick to install, can be connected and disassembled without tools, and can achieve rapid disassembly and assembly with other components. The pressure control range of the two ball valves is 0.1MPa~1MPa, and the distance between the two ball valves is 15mm. Here, two ball valves are set for sealing control. First, independent control and local isolation can be achieved, which is convenient for independently splitting the test tube 12; second, the two ball valves can provide double protection. Even if one of the ball valves fails, the other ball valve can still maintain the vacuum degree of the system to ensure the safe operation of the system.

[0034] The water bath is a constant temperature water bath 13; the temperature of the constant temperature water bath 13 is set to 80°C±1°C.

[0035] Here, if the water bath temperature is too high, the oil sample (specifically aviation lubricant) in the test tube 12 will undergo oxidation reaction, affecting the test results; in addition, the kinematic viscosity of the lubricant at 100°C is 5 , at 80℃, the kinematic viscosity is 8 -12 , the viscosity is smaller, and the corresponding fluidity is better. In addition, lubricating oil also has an important indicator, namely the air release value, which means that the lubricating oil contains a certain amount of air at room temperature; when pumping negative pressure, the smaller the viscosity, the easier it is to release the air in the lubricating oil, so that the air can be fully pumped out; therefore, choosing a temperature point where the lubricating oil is not oxidized and the viscosity is smaller is very important for building an absolute vacuum environment.

[0036] In view of this, in this embodiment, the temperature is set to 80°C ± 1°C, which can ensure that the test tube 12 does not undergo oxidation reaction in a short period of time, and the viscosity of the oil in the tube is also relatively small, which is suitable for short-term rapid degassing.

[0037] This embodiment also provides a method for using the extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil, which uses the extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil as described above to conduct thermal stability corrosion test of aviation turbine lubricating oil; the method comprises the following steps: Step 1: Assemble the extreme vacuum device for the thermal stability corrosion test of aviation turbine lubricating oil; and pre-add the oil sample to be tested into the test tube 12.

[0038] Specifically, when assembling the extreme vacuum device for the thermal stability corrosion test of aviation turbine lubricating oil, first install the vacuum gauge 5 on the iron frame 4, then connect the first vacuum tube 3 and the second vacuum tube 7 at both ends, and connect the other end of the first vacuum tube 3 to the vacuum pump 2, connect the other end of the second vacuum tube 7 to the first control valve 8, and then connect the first control valve 8 and the second control valve 9. When adding the oil sample to the test tube 12, use a glass syringe to add 6 ml of the oil sample from the port of the capillary body of the test tube 12. Then use the third vacuum tube 10 to connect the second control valve 9 and the port of the capillary body of the test tube 12.

[0039] Step 2, tilt and let the test tube 12 stand still; turn on the vacuum pump 2, the first control valve 8 and the second control valve 9, and observe the state of the oil sample in the test tube 12; within the first preset time, if the oil sample state shows that no bubbles are generated, execute the next step, otherwise, the test tube 12 is determined to be a waste tube, replace the test tube 12 and repeat this step until the oil sample state shows that no bubbles are generated within the first preset time.

[0040] In the second half of the first preset time, the test tube 12 is kept shaken; here, the shaking frequency is 1-2 seconds / time, and the shaking time is greater than 10 minutes, so as to fully remove the air in the oil sample.

[0041] Furthermore, within the first preset time, if a specific bubble feature appears in the oil sample, the test tube 12 is directly determined to be a waste tube; the specific bubble feature includes linear small bubbles; the small bubbles refer to bubbles with a diameter of 30μm to 50μm. Linear refers to multiple small bubbles connected in a linear shape. In this embodiment, the first preset time is set to 20 minutes.

[0042] In this step, by observing the state of the oil sample and using bubbles as a dominant feature to verify the gas environment in the test tube 12, the vacuum degree in the test tube 12 can be accurately determined, and whether the air tightness of the tube body meets the requirements can be verified in time, which helps to reduce the subsequent risk of tube explosion caused by tube quality.

[0043] Step 3, start the constant temperature water bath 13 and set its temperature to the target temperature, and place the test tube 12 in the constant temperature water bath 13.

[0044] The target temperature is set to 80°C ± 1°C.

[0045] Preferably, after being tilted and kept still in the constant temperature water bath 13 for 10 minutes, the test tube 12 is vibrated with a small amplitude within a second preset time until no bubbles are generated in the test tube 12. The second preset time is also set to 20 minutes. In this way, the vacuum degree inside the test tube 12 and the quality of the test tube 12 itself can be fully verified through the intuitive and visible state of the oil sample.

[0046] Step 4, observe the value of the vacuum gauge 5. When the value of the vacuum gauge 5 is lower than the reference value, close the second control valve 9, the first control valve 8, and the vacuum pump 2 in sequence.

[0047] Specifically, the reference value is set to 1.3 Pa. When the value of the vacuum gauge 5 is lower than the reference value and remains stable for a certain period of time (such as 1min~2min), it proves that a relatively high vacuum degree has been reached in the test tube 12, and the vacuum standard required for the performance test has been reached. Then, the second control valve 9, the first control valve 8, and the vacuum pump 2 are closed in sequence, so that the vacuum environment in the test tube 12 can be kept stable.

[0048] Step 5, transfer the test tube 12, and seal the test tube 12 at high temperature from the capillary.

[0049] When the test tube 12 is transferred, the second control valve 9 and the third vacuum tube 10 are transferred together. This arrangement can ensure the continuity of the vacuum environment during the transfer process, prevent the outside air from entering the system during the transfer process, and fully maintain the vacuum state of the test tube 12.

[0050] When sealing the test tube 12, an oxyacetylene flame device is used to control the oxyacetylene flame to align with the sealing position for sealing. Specifically, the oxyacetylene flame device is arranged within 1m of the ultimate vacuum device, the height of the oxyacetylene flame is 200mm±50mm, and the temperature can reach 3100℃~3400℃. In this embodiment, the sealing temperature of the high-temperature sealing is set to 820℃~850℃. Under this temperature condition, it can ensure that the material of the test tube 12 is fully melted and maintains moderate fluidity (too low temperature may cause local non-melting, resulting in micropores or cracks; too high temperature may over-soften the material, resulting in deformation or too thin sealing), forming a uniform, seamless and stable sealing layer.

[0051] The sealing position of the test tube 12 is selected to be 5cm~8cm away from the top of the tube mouth of the oxidation tube body; the width of the sealing position is set to 1cm~1.5cm; the sealing thickness is set to 3cm. Under this sealing parameter condition, the sealing width and sealing thickness are appropriately set. Among them, the size setting of 5cm~8cm has sufficient sealing area, which can enhance the sealing performance and reduce the risk of leakage. It is also more convenient to put the test tube 12 into the metal constant temperature bath without affecting the structural stress at the interface between the small tube and the large tube; the size limits of 1cm~1.5cm and 3cm can ensure that the sealing thickness is not too large, and can ensure uniform heat distribution, high sealing quality, and not easy to explode the tube.

[0052] Step 6, determine the sealing state of the test tube 12, and after the sealing state meets the standard, transfer the test tube 12 to a high temperature bath for performance testing.

[0053] In this step, the fusion sealing state meets the standard, which means that the fusion sealing mouth has an inward concave feature, and the depth of the concave feature is 1.5mm~2mm. Here, because the capillary wall will soften during fusion sealing (high borosilicate glass melts under high heat), and at the same time, because the pressure environment inside the test tube 12 is less than 1.3Pa, under the influence of the external atmospheric pressure (101.3kpa), the fusion sealing mouth will be concave inward, so when the concave seal appears, it indicates that the fusion sealing of the test tube 12 is successful, and the pressure inside the test tube 12 meets the test safety requirements, and can be transferred to the high temperature bath.

[0054] Here, a high temperature constant temperature bath set at 274°C ± 1°C may be used, and a 96-hour performance test may be performed according to the test standard.

[0055] Using this solution, the total time from removing the test tube 12 from the vacuum system to completing the sealing (corresponding to step 5 to step 6) is , which can ensure the vacuum state in the test tube 12 to a great extent.

[0056] The present embodiment provides an extreme vacuum device and method for the thermal stability and corrosion test of aviation turbine lubricating oil, which can construct an extreme vacuum environment in the test tube 12, with high vacuum degree and stable maintenance, and the overall device assembly and use costs are low, with good economy and adaptability. In addition, in actual test applications, we used this vacuum device to complete 200 sets of thermal stability and corrosion test tests of aviation turbine engine lubricating oil. During the test, multiple test tubes 12 experienced a strict temperature change environment (room temperature → 274℃ high temperature bath), but all test tubes 12 did not explode. It can be seen that this device has strong reliability, and also indirectly verifies the compliance and stability of the vacuum environment in the test tube 12. Compared with the previous test method of using a pump to directly connect the test tube 12 to extract vacuum, this solution can reduce the risk of tube explosion from 2 to 5 times per 10 groups of tests to 0 times, with significant results.

[0057] The following is a description of the application effect of this solution in combination with a specific comparative example: Comparative Example 1: In the existing thermal stability and corrosion test, during the vacuum stage, a traditional vacuum device is used to directly vacuum the test tube 12 through a pipeline.

[0058] Comparative Example 2: Based on this solution, the first control valve 8 is not provided.

[0059] Comparative Example 3: Based on this solution, the second control valve 9 is not provided.

[0060] Comparative Example 4: Based on this solution, no multi-level pipeline is provided.

[0061] The solutions of this embodiment and comparative examples 1-4 were respectively adopted to prepare a test tube 12 under the premise that other test conditions were the same, and six groups of thermal stability and corrosion tests were carried out. The test results are shown in Tables 1 and 2.

[0062] Table 1 Pipe explosion results

[0063] Table 2 Vacuum conditions (the ultimate vacuum degree that can be achieved in the test tube)

[0064] It can be seen from Table 1 and Table 2 that, in the six groups of tests, tube explosion occurred in Comparative Examples 1 to 4, but no tube explosion occurred in the present embodiment; and, the ultimate vacuum degree that can be achieved by Comparative Examples 1 to 4 cannot meet the standard requirements, but the present embodiment can meet the standard requirements and even improve on the basis of meeting the standards.

[0065] It can be seen that the solution provided in this embodiment has obvious advantages, and the constructed vacuum environment meets the standards and can remain stable in an extreme test environment for a long time.

[0066] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field are aware of all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement the scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for the ordinary technicians in the relevant field to implement this application. It should be pointed out that for the technicians in this field, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. The extreme vacuum device for thermal stability and corrosion test of aviation turbine lubricating oil is characterized by: It comprises a vacuum pump, a vacuum gauge, a first control valve, a second control valve and a water bath which are arranged in sequence; a first vacuum tube is connected between the vacuum pump and the vacuum gauge; a second vacuum tube is connected between the vacuum gauge and the first control valve; a vacuum clamp is connected between the first control valve and the second control valve; the second control valve is connected to the inside of the test tube through a third vacuum tube; the water bath is a constant temperature water bath; The test tube comprises a capillary body and an oxidation tube body which are integrally connected; the third vacuum tube is connected to the capillary body.

2. The extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil according to claim 1, characterized in that: The first vacuum tube and the second vacuum tube are both high vacuum bellows; the third vacuum tube is a thick-walled silicone tube.

3. The extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil according to claim 1, characterized in that: The first control valve is a high vacuum ball valve; the second control valve is a double pagoda head ball valve.

4. The extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil according to claim 1, characterized in that: The temperature of the constant temperature water bath is set to 80°C ± 1°C.

5. The extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil according to claim 2, characterized in that: The lengths of the first vacuum tube and the second vacuum tube are set to 100 cm±10 cm; and fastening rings are provided at both ends of the first vacuum tube and the second vacuum tube.

6. The method for using the extreme vacuum device for the thermal stability corrosion test of aviation turbine lubricating oil is characterized in that: The aviation turbine lubricating oil thermal stability corrosion test is carried out using the aviation turbine lubricating oil thermal stability corrosion test extreme vacuum device as described in any one of claims 1 to 5; the test comprises the following steps: Step 1: Assemble the extreme vacuum device for the thermal stability corrosion test of aviation turbine lubricating oil; and pre-add the oil sample to be tested into the test tube; Step 2, tilting and standing the test tube; and turning on the vacuum pump, the first control valve and the second control valve, and observing the state of the oil sample in the test tube; if the state of the oil sample shows that no bubbles are generated within the first preset time, then executing the next step; otherwise, the test tube is determined to be a waste tube, and the test tube is replaced and this step is repeated until the state of the oil sample shows that no bubbles are generated within the first preset time; Step 3, start the constant temperature water bath and set its temperature to the target temperature, and place the test tube in the constant temperature water bath; Step 4, observe the vacuum gauge value, when the vacuum gauge value is lower than the reference value, close the second control valve, the first control valve, and the vacuum pump in sequence; Step 5, transferring the test tube and sealing the test tube at high temperature from the capillary tube; Step 6, determine the sealing state of the test tube, and after the sealing state meets the standard, transfer the test tube to a high temperature bath for performance testing.

7. The method for using the extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil according to claim 6, characterized in that: In the second half of the first preset time, the test tube is kept shaking; and within the first preset time, if specific bubble characteristics appear, the test tube is directly determined to be a waste tube; the specific bubble characteristics include linear small bubbles; the small bubbles refer to bubbles with a diameter of 30μm~50μm.

8. The method for using the extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil according to claim 6, characterized in that: In step 5, when the test tube is transferred, the second control valve and the third vacuum tube are transferred together.

9. The method for using the extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil according to claim 6, characterized in that: In step 5, the sealing position of the test tube is selected to be 5 cm to 8 cm away from the top of the tube mouth of the oxidation tube body; the width of the sealing position is set to 1 cm to 1.5 cm; the sealing thickness is set to 3 cm; and the sealing temperature of the high-temperature sealing is set to 820°C to 850°C.

10. The method for using the extreme vacuum device for thermal stability corrosion test of aviation turbine lubricating oil according to claim 6, characterized in that: In step 6, the fusion sealing state meets the standard, which means that an inward concave feature appears at the fusion sealing opening, and the depth of the concave feature is 1.5 mm to 2 mm.

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