Method for testing filtering performance of filter element under simulated vibration working condition

Abstract

The invention discloses a method for testing the filtering performance of a filter element under a simulated vibration working condition, which is characterized in that vibration parameters and filtering performance testing are combined for the first time through a test system by integrating a created vibration environment, so that the test environment is more vivid to an actual use scene, and the vibration effect of the filtering performance is synchronously and simultaneously detected; the device and the method help engineering technicians to improve the anti-vibration design of the filter element and master the filtering and purifying capacity of the filter element in actual use, provide reproducible verification support and a reliable scientific tool for actually evaluating the filtering performance and manufacturing quality of the filter element, and play a guiding role in promoting updating and upgrading of test standards in the filter industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of testing the filtration performance of filter elements using oil as the working medium, and specifically relates to a method for testing the filtration performance of filter elements under simulated vibration conditions. The method is suitable for performance evaluation of filter elements in hydraulic systems, engine oil systems, fuel systems, and lubricating oil systems under vibration conditions in engineering vehicles, road vehicles, transportation equipment, aerospace, and the like. Background Art

[0002] The filtration performance of filter elements for hydraulic filters (oil, fuel, and lubricating oil filters) mainly includes performance indicators such as filtration ratio (filtration accuracy and filtration efficiency), dirt holding capacity, and flow characteristics. These indicators are usually tested and evaluated using the multi-pass particle counting test method (GB / T 18853, ISO 16889; GB / T 8243.12, ISO 4548-12; QC / T 1007, ISO 19438, ISO / TS13353). The test conditions of existing national, international, or industry standards are generally steady-state operating conditions, which are idealized test methods that do not consider the impact of the vibration environment.

[0003] In actual applications, the hydraulic system filters (filter elements) of engineering equipment, the filter elements on vehicles or the engine filters generally work under vibration conditions. The filtering and purification effect of the filter elements working under vibration conditions will inevitably be different from that under steady-state conditions.

[0004] Compared with the steady-state environment, the vibration condition may cause the filtration performance to decline. Its impact mechanism is mainly manifested in the following aspects:

[0005] (1) During the test, the test dust intercepted by the filter element may fall off multiple times due to vibration and impact, resulting in a decrease in filtration efficiency;

[0006] (2) The connection seal of the filter element joint may fail or become loose due to vibration and impact, thus affecting the test results of filtration accuracy and filtration efficiency;

[0007] (3) Under the action of vibration and impact, the corrugated structure of the filter element and filter material may be deformed or damaged, changing the structural integrity and thus reducing the filtering performance.

[0008] It can be seen from this that there is a certain deviation between the test data obtained by the traditional commonly used steady-state detection experimental method and the actual working conditions.

[0009] Therefore, in order to introduce the influencing factors of the vibration environment, a test method for detecting the filtering performance of the filter element under simulated vibration working conditions is proposed to make up for the defect that the filter element performance test results deviate from the actual situation, and to play the role of experimental verification and quality control for accurately evaluating the manufacturing quality of the filter element and the simulation evaluation of the filtering performance. Summary of the Invention

[0010] The purpose of the present invention is to provide a method for testing the filtering performance of a filter element under simulated vibration conditions. This method makes the test conditions simulate the real vibration working environment as much as possible, so as to test and evaluate the filtering performance of the hydraulic filter element under actual working conditions, and optimize the matching of better filter elements for designing the best pollution control solution for the oil system.

[0011] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: a method for testing the filtration performance of a filter element under simulated vibration conditions, characterized by the following specific steps:

[0012] Step S1: The multi-pass test bench configured for hydraulic filters shall meet the requirements of GB / T 18853 (ISO 16889) "Hydraulic transmission filters - Multiple-pass method for evaluating filter element filtration performance". The multi-pass test bench configured for vehicle filters (such as the "three filters" of an automobile) shall meet the requirements of GB / T 8243.12 (ISO 4548-12) "Test methods for full-flow oil filters for internal combustion engines - Part 12: Determination of filtration efficiency and dirt holding capacity by particle counting method" for oil filters, and the requirements of QC / T 1007 (ISO 19438) or GB / T 35359 (ISO / TS13353) "Automotive fuel filters - Evaluation of filtration performance - Particle counting method" for fuel filters.

[0013] Step S2: The configuration of the vibration table should meet the technical requirements of GB / T 13310 "Electric Vibration Table";

[0014] Step S3: The hose connecting the test closed oil circuit should meet the requirements of GB / T44072.1 "Hydraulic transmission connecting hose assembly Part 1 Dimensions and requirements" and GB / T 44072.2 "Hydraulic transmission connecting hose assembly Part 2 Operating procedures";

[0015] Step S4: The tested hydraulic filter element is vertically mounted on the vibration table along with the test fixture. The specific mounting and fixing method shall meet the requirements of GB / T 8243.7 (ISO 4548-7) "Test methods for full-flow oil filters for internal combustion engines - Part 7: Vibration fatigue test" (or other relevant vibration test standards);

[0016] Step S5: Depending on the hydraulic filter element being tested, the system cleaning of the multi-pass test bench, the preparation of the dust concentrate, and the setting of the flow rate, temperature, pressure, and particle size are performed in accordance with conventional steady-state multi-pass test standards, such as GB / T 18853 for hydraulic filter elements, to complete the preparation work for the hydraulic filter element filtration performance test;

[0017] Step S6: setting the vibration axis of the vibration table to the vertical direction, and setting the vibration frequency and acceleration vibration test parameters;

[0018] Step S7: Use intermittent vibration mode to simulate the "running and stopping" of the equipment in the power-on state. Start the vibration test bench 5 minutes after the multi-pass test system is turned on. Use sweep frequency or fixed frequency vibration mode. Each time the sweep frequency vibration is repeated, the same round-trip sweep time is paused. Repeat this process to simulate the vibration environment until the entire test is completed. If the frequency is fixed, vibrate for 5 to 10 minutes, then pause for 5 to 10 minutes before vibrating again.

[0019] Step S8: Replace the test piece with a straight-through connector or fixture with the same diameter as the hose to form an oil circulation test system. The hose is connected in the same extended position as when connected to the test piece, and the multi-pass test bench is turned on. The resistance P0 of the hose under the test flow condition is measured and recorded in kPa.

[0020] Step S9: Install and fix the hydraulic filter element to be tested, measure and record the initial resistance P1 under the test flow conditions, in kPa. The clean and static pressure difference of the filter element is △P, which is calculated according to formula (1):

[0021] △P=P1-P0 (1)

[0022] Step S10: Start the upstream and downstream particle counting systems of the multi-pass test bench and the pollution injection system of the test dust concentrate. After 5 minutes, start the vibration test bench again and test the filtration performance simultaneously under intermittent vibration conditions, that is, monitor (automatically record) the initial pressure difference of the filter element, the upstream and downstream particle counts (filtration ratio and filtration efficiency), and the pressure difference rising rate (test life / pollution holding capacity) in real time;

[0023] Step S11: Assume that the limit pressure difference of the filter element under test is △P max When the filter element pressure difference △P rises to the end pressure difference △P 终止 The test is stopped at this time, and the final pressure difference of the filter element is calculated according to formula (2):

[0024] △P 终止 =P1-P0+△P max =△P+△P max (2)

[0025] Step S12: After the test is completed, data calculation and processing are performed according to the requirements of conventional steady-state multi-pass test standards such as GB / T 18853, and performance parameters such as filtration accuracy and filtration efficiency, and dirt holding capacity (test life) are reported;

[0026] Step S13: If necessary, compare the filtration performance under vibration and steady state and the bubbling pressure before and after the filter element test, and draw the characteristic curve of the filter element pressure difference, filtration ratio (filtration efficiency) and dirt holding capacity and test life (time) to analyze and evaluate the stability of the filter element performance and provide guidance for subsequent optimization and improvement.

[0027] The present invention has the following advantages and beneficial effects: the present invention can help engineering technicians understand the true filtering and purification capacity, i.e., filtering performance, of hydraulic filter elements in actual use, reduce the distortion of test performance under steady-state test conditions, and provide technical and verification support for accurately grasping the pollution control level of the oil system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of multiple passes in vibration conditions.

[0029] Figure 2 This is a schematic diagram of the vibration table test connection. DETAILED DESCRIPTION

[0030] The above contents of the present invention are further described in detail below through examples, but this should not be understood as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above contents of the present invention fall within the scope of the present invention.

[0031] In order to create a test system for the filtration performance of hydraulic filter elements under vibration conditions, it is necessary to integrate a corresponding vibration device into the existing commonly used filtration performance test system so that during the performance test of the filter element, the vibration device can provide the filter element under test with environmental conditions that simulate actual vibration conditions.

[0032] like Figure 1 The figure below is a schematic diagram of a test system for testing hydraulic filtration accuracy, filtration efficiency, and dirt holding capacity under simulated vibration conditions. The multi-pass test bench is a steady-state filtration performance test system that meets the requirements of the corresponding standards. The integrated configuration of the vibration table and multi-pass test bench must not only meet the test standards for the filter element being tested but also facilitate the control and operation of the test system. The test filter is fixed to the vibration table surface according to the vibration test requirements. A hose is used to connect the test filter to the oil line interface of the multi-pass test bench, thus forming a closed multi-pass and vibration test cycle system.

[0033] Example 1

[0034] The filtration performance test of aviation hydraulic filter elements under simulated vibration conditions is carried out. The multiple-pass test refers to GB / T18853 or ISO 16889 "Hydraulic transmission filter - Multiple-pass method for evaluating filter element filtration performance". The vibration test requirements refer to the national military standard GJB 150.16A "Vibration test for environmental test methods of military equipment". Assuming the test cycle flow rate is 160L / min, the ultimate pressure difference △P max =550kPa.

[0035] A method for testing the filtration performance of an aviation hydraulic filter element under simulated vibration conditions comprises the following specific steps:

[0036] Step S1: Prepare and verify multiple passes of the test in accordance with the requirements of GB / T 18853. The test dust (ISO MTD) concentration is 10 mg / L, the flow rate is set to 160 L / min, and the sizes of the upstream and downstream automatic particle counts are set to: 4 μm, 5 μm, 7 μm, 10 μm, 15 μm, 20 μm, and the limit pressure difference △P max 550kPa;

[0037] Step S2: If conditions permit, test and record the bubbling pressure and appearance quality of the tested filter element;

[0038] Step S3: Prepare for the vibration test according to GJB 150.16A. Adjust the vibration axis to the vertical direction, set the sinusoidal sweep frequency to 5-2000 Hz, the acceleration to 1-20 g, the amplitude to 0.1-5 mm, and the round-trip sweep time to 10 minutes (generally 10-15 minutes).

[0039] Step S4: Figure 2 As shown, the filter under test (or tooling and filter element) 5 is mounted and fixed on the vibration table fixing surface 6 via the fixing bracket 3. The fixing bolts 2 are tightened to ensure that the filter axis is perpendicular to the vibration table surface. The accelerometers at the input end 1 and the output end 4 are placed as shown and connected to the recorder with wires. The schematic structure of the fixing bracket 3 is not the only one and depends on the fixing method of the filter under test. The connection stiffness with the vibration table must be good.

[0040] Step S5: Reference Figure 1 Connect the test hose, oil hose and the test filter to avoid "dead bends" and overcome the interference with vibration;

[0041] Step S6: After the test conditions are met, record the ambient temperature, humidity, and oil temperature, start the multi-pass test bench, and measure and record the hose resistance P0 and initial resistance P1 (kPa) at a flow rate of 160 L / min;

[0042] Step S7: Start the timer to enter the multi-pass test program according to the test requirements of GB / T 18853. After 5 minutes, start the vibration table and the multi-pass test synchronization test program according to the requirements of GJB150.16A. The intermittent scanning vibration interval is 10 minutes.

[0043] Step S8: Observe the test operation and confirm the automatic particle counting system, test flow rate, test dust injection flow rate, and pressure difference during each upstream and downstream particle counting;

[0044] Step S9: When the pressure difference reaches the end pressure difference ΔP 终止 (△P 终止 =P1-P0+550kPa) is 80% to 100%, the multi-pass test enters the relevant operations of ending the test procedure and shuts down the vibration test system;

[0045] Step S10: Calculate data and organize records according to the requirements of GB / T 18853, retest the non-spin-on decomposable filter and record the filter element bubbling pressure and appearance quality. Refer to the format in Table 1 to organize the test conditions, vibration system, test results and other related information into a test report;

[0046] Table 1 Vibration multiple pass test report

[0047]

[0048] Table 1 (Continued or continued page)

[0049]

[0050] Step S11: Check the integrity of the filter element's appearance quality, compare the bubbling pressure before and after the test, and evaluate the filter element's filtering performance.

[0051] Example 2

[0052] The filtration performance test of the automotive oil filter element under simulated vibration conditions, multiple pass tests refer to GB / T8243.12 or ISO 4548-12 "Internal combustion engine full-flow oil filter test method Part 12: Determination of filtration efficiency and dirt holding capacity by particle counting method", and the vibration test requirements refer to GB / T 8243.7 or ISO 4548-7 "Internal combustion engine full-flow oil filter test method Part 7: Vibration fatigue test", assuming the test cycle flow rate is 60L / min, the ultimate pressure difference △P max =125kPa.

[0053] A method for testing the filtering performance of an oil filter element under simulated vibration conditions comprises the following specific steps:

[0054] Step S1: Prepare and verify multiple passes of the test in accordance with the requirements of GB / T 8243.12. The test dust (ISO MTD) concentration is 10 mg / L, the flow rate is set to 60 L / min, and the sizes of the upstream and downstream automatic particle counts are set to: 4 μm, 5 μm, 6 μm, 7 μm, 9 μm, 10 μm, 11 μm, 13 μm, 15 μm, 17 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, and the limit pressure difference △P max 125kPa;

[0055] Step S2: If conditions permit, test and record the bubbling pressure and appearance quality of the tested filter element (except for spin-on filters due to packaging);

[0056] Step S3: Prepare for the vibration test according to the requirements of GB / T 8243.7, adjust the vibration axis to the vertical direction, set the fixed vibration frequency to 400 Hz, the acceleration to 1-6 g, the amplitude to 0.1-5 mm, and set the vibration interval time to 6 minutes;

[0057] Step S4: Install and fix the test product in accordance with the requirements of GB / T 8243.7, where the connection between the oil hose and the test filter avoids "dead bends" and can overcome interference with vibration;

[0058] Step S5: After the test conditions are met, record the ambient temperature, humidity, and oil temperature, start the multi-pass test bench, measure the initial value at a flow rate of 60 L / min, and record the hose resistance P0 and the cleaning assembly pressure difference P1 (kPa);

[0059] Step S6: Start the timer to enter the multi-pass test program according to the test requirements of GB / T 8243.12. After 5 minutes, start the vibration table and the multi-pass test synchronization test program according to the requirements of GB / T 8243.7. The intermittent vibration interval is 6 minutes;

[0060] Step S7: Observe the test operation and confirm the automatic particle counting system, test flow rate, test dust injection flow rate, and pressure difference during each upstream and downstream particle counting;

[0061] Step S8: When the pressure difference reaches the end pressure difference ΔP 终止 (△P 终止 =P1-P0+125kPa) is 80% to 100%, the multi-pass test enters the relevant operations of ending the test procedure and shuts down the vibration test system;

[0062] Step S9: According to the requirements of GB / T 8243.12, calculate data, organize records, and if feasible, test and record the bubbling pressure and appearance quality of the filter element again. Refer to Table 1 to organize the test conditions, vibration parameters, test results and other related information into a test report. According to the test requirements, report the filtration efficiency (%) and dust holding capacity (g) of particle sizes such as 4μm, 5μm, 6μm, 7μm, 9μm, 10μm, 11μm, 13μm, 15μm, 17μm, 20μm, 25μm, 30μm, 40μm, and 50μm under vibration conditions. Calculate the rated micron particle size (μm) at filtration efficiencies of 90%, 95%, and 99% using linear interpolation based on the relevant test data.

[0063] Step S10: Evaluate the filtration performance of the filter under the vibration environment, and if applicable, evaluate the integrity of the filter element structure.

[0064] The above embodiments describe the basic principles, main features, key elements and advantages of the present invention. Technicians in the filter industry should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the scope of the principles of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for testing the filtration performance of a filter element under simulated vibration conditions, characterized in that The specific steps are: Step S1: The multi-pass test bench configured for hydraulic filters shall meet the requirements of GB / T 18853 (ISO 16889) "Hydraulic transmission filters - Multiple-pass method for evaluating filter element filtration performance". The multi-pass test bench configured for vehicle filters shall meet the requirements of GB / T 8243.12 (ISO 4548-12) "Test methods for full-flow oil filters for internal combustion engines - Part 12: Determination of filtration efficiency and dirt holding capacity by particle counting method" for oil filters, and the requirements of QC / T 1007 (ISO 19438) or GB / T 35359 (ISO / TS13353) "Automotive fuel filters - Evaluation of filtration performance - Particle counting method" for fuel filters. Step S2: The configuration of the vibration table should meet the technical requirements of GB / T 13310 "Electric Vibration Table"; Step S3: The hose used to connect the closed oil circuit for the test shall meet the requirements of GB / T 44072.1 "Hydraulic transmission connecting hose assemblies - Part 1 - Dimensions and requirements" and GB / T 44072.2 "Hydraulic transmission connecting hose assemblies - Part 2 - Operating procedures"; Step S4: The tested hydraulic filter element is vertically mounted on the vibration table along with the test fixture. The specific mounting and fixing method shall meet the requirements of GB / T 8243.7 (ISO 4548-7) "Test methods for full-flow oil filters for internal combustion engines - Part 7: Vibration fatigue test"; Step S5: Depending on the hydraulic filter element being tested, the system cleaning of the multi-pass test bench, the preparation of the dust concentrate, and the setting of the flow rate, temperature, pressure, and particle size are performed in accordance with conventional steady-state multi-pass test standards, such as GB / T 18853 for hydraulic filter elements, to complete the preparation work for the hydraulic filter element filtration performance test; Step S6: setting the vibration axis of the vibration table to the vertical direction, and setting the vibration frequency and acceleration vibration test parameters; Step S7: Use intermittent vibration mode to simulate the "running and stopping" of the equipment in the power-on state. After the multi-pass test system is turned on for 5 minutes, start the vibration test bench again. Use sweep frequency or fixed frequency vibration mode. After each round trip of sweep frequency vibration, pause for the same round trip sweep time. Repeat this process to simulate the vibration environment until the entire test is completed. If it is a fixed frequency, vibrate for 5 to 10 minutes, pause for 5 to 10 minutes, and then vibrate again. Step S8: Replace the test piece with a straight-through connector or fixture with the same diameter as the hose to form an oil circulation test system. The hose is connected in the same extended position as when connected to the test piece, and the multi-pass test bench is turned on. The resistance P0 of the hose under the test flow condition is measured and recorded in kPa. Step S9: Install and fix the tested hydraulic filter element, measure and record the initial resistance P1 under the test flow conditions, in kPa. The clean and static pressure difference of the filter element is ΔP, which is calculated according to formula (1): ΔP=P1-P0 (1) Step S10: Start the upstream and downstream particle counting systems of the multi-pass test bench and the pollution injection system of the test dust concentrate. After 5 minutes, start the vibration test bench again and test the filtration performance simultaneously under intermittent vibration conditions, that is, monitor (automatically record) the initial pressure difference of the filter element, the upstream and downstream particle counts (filtration ratio and filtration efficiency), and the pressure difference rising rate (test life / pollution holding capacity) in real time; Step S11: Assume that the limit pressure difference of the filter element under test is ΔP max , when the filter element pressure difference ΔP rises to the end pressure difference ΔP 终止 The test is stopped at this time, and the final pressure difference of the filter element is calculated according to formula (2): ΔP 终止 =P1-P0+ΔP max =ΔP+ΔP max (2) Step S12: After the test is completed, data calculation and processing are performed according to the requirements of conventional steady-state multi-pass test standards such as GB / T 18853, and performance parameters such as filtration accuracy and filtration efficiency, and dirt holding capacity (test life) are reported; Step S13: If necessary, compare the filtration performance under vibration and steady state and the bubbling pressure before and after the filter element test, and draw the characteristic curve of the filter element pressure difference, filtration ratio and dirt holding capacity and test life to analyze and evaluate the stability of the filter element performance and provide guidance for subsequent optimization and improvement.

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