A method for screening hydraulic pump for underwater acoustic equipment

Abstract

The application discloses a kind of hydraulic pump screening test methods for underwater acoustic equipment, first the common failure of hydraulic pump is analyzed, then based on the above common failure, targeted screening test method is proposed, various tests are carried out;Finally, after completing all the above tests, performance test test is carried out.The beneficial effects of the present application are as follows: the axial plunger pump screening test method can carry out the preliminary screening of the early problems of plunger pump production and assembly, which is conducive to grasping the consistency and stability of product performance, and can be used as a reference for other products such as plunger pump.The screw pump screening test method described in the present application increases high-speed test, full-load test and working condition test in combination with the use environment of screw pump, aiming to eliminate defective products and unqualified products through non-destructive short-time performance test and extreme working condition test before installation, to screen out qualified products that meet the use requirements of important host equipment, to establish a screw pump installation access method, and to reduce the life cycle use risk of screw pump.

Description

Technical Field

[0001] This invention relates to the field of hydraulic pump testing technology, and mainly to a screening test method for hydraulic pumps used in underwater acoustic equipment. Background Technology

[0002] Hydraulic pumps are an important energy conversion element in hydraulic transmission systems, mainly including piston pumps and screw pumps.

[0003] Axial piston pumps are an important energy conversion element in hydraulic transmission systems, possessing advantages such as high parameters, high efficiency, long service life, convenient variable displacement, and high power density. Piston pumps are mainly used in the main oil circuit and control oil circuit of pump stations, providing high-pressure oil and control oil to the hydraulic system, making them key components in the operation of the hydraulic system.

[0004] According to the test standard for "Hydraulic Axial Piston Pump" (JB / T7043-2006), axial piston pumps need to undergo "type testing" after being finalized and "factory testing" in subsequent production. However, the performance consistency of domestically produced axial piston pumps is insufficient, and factory testing alone is not enough to eliminate defective products with early defects or failures caused by material defects or process failures.

[0005] The screening test approach: Every axial piston pump has weak points. Common failures occur in the distribution pair, slipper pair, piston pair, seals, variable displacement mechanism, and bearings. By conducting screening tests with strength lower than type tests on top of conventional tests, defective or substandard products caused by the manufacturing process can be eliminated in a short time without damaging the axial piston pump or affecting its subsequent use. Based on this approach, failure mode effect and hazard analysis can be used to identify the weakest point of the axial piston pump, and corresponding tests can be designed to achieve the desired screening effect.

[0006] Screw pumps, as a type of positive displacement pump, are widely used in agriculture, petroleum, chemical, metallurgy, shipbuilding, and other industries. With the needs of production development, the variety of screw pumps is increasing. During use, various problems may arise, such as low pump efficiency, excessive vibration and noise, and pump failure. For critical main equipment, screw pumps must undergo rigorous screening and inspection before delivery to eliminate defective or substandard products caused by the production process, thereby improving their reliability in actual use and ensuring smooth system operation.

[0007] Existing screw pump testing standards specify test methods for factory performance testing of screw pumps, such as the national standard GB / T11705-2009 "Test Methods for Marine Electric Three-Screw Pumps" and the industry standard JB / T 8091-2014 "Test Methods for Screw Pumps." Factory performance testing of screw pumps mainly includes parameters such as volumetric efficiency and maximum pressure. However, for critical main equipment, it is not possible to conduct targeted performance verification and functional matching of screw pumps before use. Therefore, it is necessary to conduct screw pump screening tests based on the operating environment and conditions of critical main equipment to identify defective and unqualified products, ensuring the usability of screw pumps in critical main equipment.

[0008] Currently, there is no universally accepted standard method for screening and testing screw pumps. Scientifically and effectively conducting pre-installation screening tests on screw pumps, taking into account the characteristics of the host equipment's operating environment, and identifying defective and unqualified products, is crucial for improving the reliability of critical host equipment during actual use and ensuring smooth system operation. Therefore, it is necessary to design a screening and testing method for screw pumps used in sonar equipment, including specific screening test items, testing methods, and inspection methods. By conducting pre-installation screening and inspection of screw pumps, an access criterion for screw pumps in critical host equipment can be established, and qualified screw pump products can be selected. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a screening test method for hydraulic pumps used in underwater acoustic equipment.

[0010] The objective of this invention is achieved through the following technical solution: A screening test method for hydraulic pumps used in underwater acoustic equipment. First, common hydraulic pump failures are analyzed. Then, based on these common failures, targeted screening test methods are proposed, and corresponding tests are conducted. After completing all the above tests, performance testing is performed. Finally, data processing and test result judgment are performed.

[0011] When the hydraulic pump is an axial piston pump, the specific steps include the following:

[0012] First, common failures of axial piston pumps are analyzed, mainly including: copper residue and burning on the distributor plate; cracking and detachment of the sintered layer in the bimetallic cylinder block; copper residue and burning on the swashplate; slipper loosening, slippage, uneven wear or severe wear; severe wear of the return plate; damage to the return plate, etc.; piston seizing in the cylinder bore; seal failure; breakage of variable displacement mechanism parts, spline damage, etc.; burning of sliding bearings; and damage to rolling bearings (pitting on rolling elements). Tests conducted to address these failures of the axial piston pump include efficiency characteristic tests, high-temperature tests, low-temperature tests, impact tests, overspeed and high-displacement tests, and overload tests. After each test, variable displacement characteristic tests, efficiency characteristic retests, and seal performance checks are performed.

[0013] The evaluation process includes several key components: efficiency characteristic testing and subsequent efficiency characteristic retesting. The efficiency characteristic test uses the volumetric efficiency and overall efficiency of the axial piston pump as evaluation criteria, comparing performance changes before and after the screening test to eliminate defective or substandard products. The high-temperature test assesses the performance of the seals and the quality and processability of materials used in each moving friction pair under low oil viscosity conditions. The low-temperature test assesses the performance of the seals and the fitting accuracy of each moving friction pair under high oil viscosity conditions. The impact test accelerates wear on each moving friction pair through high and low pressure switching, revealing material and process issues in the production process. The overspeed and high-displacement test verifies the high-speed performance of the tested pump after a series of screening tests and initially tightens the working conditions of the pump's piston pair. To further screen the wear resistance of the piston pair, the test continues under the rated operating conditions of the axial piston pump. The overload test is a comprehensive test of the friction of each moving friction pair, the reliability of the seals, and the variable displacement mechanism. After completing the above tests, variable displacement characteristic testing, efficiency characteristic retesting, and sealing performance checks are performed to examine performance changes in the axial piston pump.

[0014] The test method for efficiency characteristics is as follows:

[0015] The test procedure is as follows: a) At maximum displacement and rated speed, gradually increase the outlet pressure of the pump under test to 25% of the rated pressure. After the test condition stabilizes, measure the data related to efficiency.

[0016] b) Using the above method, when the outlet pressure of the pump under test is the rated pressure and the speed is the rated speed, measure the output flow rate of the pump under test when the ambient temperature is 20℃~35℃ and 50℃~60℃ respectively.

[0017] c) With the pump under test in no-load condition and at the rated speed, measure the output flow rate of the pump under test when the ambient temperature is 20℃~35℃ and 50℃~60℃ respectively.

[0018] d) Calculate the volumetric efficiency and overall efficiency.

[0019] The high-temperature test method is as follows: the pump under test is operated continuously for more than 1 hour at rated speed and rated pressure, with an ambient temperature of 50±5℃ and an oil viscosity not lower than the minimum allowable viscosity of the pump under test.

[0020] The test method for low-temperature testing is as follows: To meet the low-temperature (-25℃ to 0℃) start-up requirements of the axial piston pump, a low-temperature performance test will be conducted for screening. To simulate actual working conditions and meet the operational needs of this axial piston pump in a low-temperature environment, the entire test bench will be placed in a low-temperature chamber to test, verify, and study the low-temperature performance of the low-temperature piston pump.

[0021] a) With the pump under test at no load, rated speed, zero displacement, and an ambient temperature of -25℃, use L-HV type low temperature anti-wear hydraulic oil and start the pump under test at least five times.

[0022] b) With the pump under test at no load, rated speed, 0.5 times the maximum displacement, and an ambient temperature of -25℃, use L-HV type low temperature anti-wear hydraulic oil and start the pump under test at least five times.

[0023] The impact test method is as follows: The pump under test is subjected to 500 impacts at rated speed, with a high pressure of 35 MPa and a low pressure of 10 MPa, and a square wave frequency of 0.1 Hz. During the test, the temperature is controlled between 25℃ and 40℃.

[0024] The test method for high-speed, large-displacement engine tests is as follows:

[0025] a) Run the pump under test continuously at its maximum speed and under no-load for more than 15 minutes. The ambient temperature during the test is 25℃~40℃. The purpose of the first step of the test is to verify the high-speed performance of the pump under test after a series of screening tests, and to initially tighten the working conditions of the plunger assembly of the pump under test. If no abnormal heating or noise occurs, proceed to the next step of the test.

[0026] b) In order to further screen the wear resistance of the plunger pair of the tested pump, the speed was restored to the rated speed in this step of the test. The specific test plan is as follows: run continuously for more than 15 minutes at rated speed, maximum displacement and pressure of 35MPa. During the test, the ambient temperature is controlled between 25℃ and 40℃.

[0027] The overload test method is as follows: Under rated speed and peak pressure conditions, operate continuously for more than 1 minute, with the ambient temperature controlled between 25℃ and 40℃. Check for any abnormal phenomena.

[0028] The experimental method for variable characteristic testing is as follows:

[0029] a) Determination of the minimum pressure switching point: Adjust the variable mechanism to bring the pump under test to the minimum pressure switching state and measure the outlet pressure of the pump under test;

[0030] b) Determination of the highest pressure switching point: Adjust the variable mechanism to bring the tested pump to the highest pressure switching state and measure the pump outlet pressure;

[0031] c) Determination of constant power characteristics: Adjust the variable mechanism according to the design requirements, measure the corresponding data of pressure and flow rate, and plot the constant power characteristic curve (pressure-flow characteristic curve).

[0032] After completing the above tests, the efficiency characteristics were retested. The retesting method is as follows:

[0033] a) At maximum displacement and rated speed, gradually increase the outlet pressure of the pump under test to 25% of the rated pressure. After the test condition stabilizes, measure the data related to efficiency.

[0034] b) Using the above method, when the outlet pressure of the pump under test is the rated pressure and the speed is the rated speed, measure the output flow rate when the inlet oil temperature of the pump under test is 20℃~35℃ and 50℃~60℃ respectively.

[0035] c) With the pump under test in no-load condition and at the rated speed, measure the output flow rate of the pump under test when the inlet oil temperature is 20℃~35℃ and 50℃~60℃ respectively.

[0036] d) Calculate the volumetric efficiency and overall efficiency.

[0037] The test method for checking the sealing performance is as follows: Clean the pump under test. If some parts cannot be cleaned completely in one go, and a "false" leakage occurs after operation, it is permissible to clean them again. After the pump stops running, press clean absorbent paper onto the static sealing area, then remove it and check whether oil droplets appear on the absorbent paper. If there are oil stains on the paper, it indicates leakage; if no oil stains appear, the sealing performance is normal.

[0038] Using experimental data and the following formulas, the relevant performance indicators of the axial piston pump were calculated.

[0039] Volumetric efficiency:

[0040]

[0041] Overall efficiency:

[0042]

[0043] Mechanical efficiency:

[0044]

[0045] Output hydraulic power:

[0046]

[0047] Input mechanical power:

[0048]

[0049] In the formula:

[0050] q v2,i — Output flow rate at no-load pressure, L / min;

[0051] q v2,e — Output flow rate at test pressure, L / min;

[0052] qv1,e —Input flow rate at test pressure, L / min;

[0053] n e — Rotational speed at the test pressure, in r / min;

[0054] n i — Rotational speed under no-load pressure, r / min;

[0055] V 2,e —Displacement at test pressure, mL / r;

[0056] V 2,i —No-load displacement at no-load pressure, mL / r;

[0057] P 2,e — Output test pressure, kPa;

[0058] P 1,e — Input pressure, positive if greater than atmospheric pressure, negative if less than atmospheric pressure, kPa;

[0059] T1 — Input torque, N·m.

[0060] Furthermore, after completing the above tests, axial piston pumps with significant performance changes after a series of tests and those exhibiting abnormal vibration and noise during the tests were excluded. The qualification criteria for the tested pumps were determined as follows: (1) the volumetric efficiency and total efficiency of the tested pumps changed by no more than ±1.5% compared to the first test; (2) there was no abnormal vibration and noise during the test. If the test sample did not meet either of the above two criteria, it was considered to be eliminated in the screening test.

[0061] When the hydraulic pump is a screw pump, the specific steps are as follows:

[0062] First, we analyze common screw pump failures, which mainly include: insufficient pump output flow, insufficient pump pressure build-up capacity, abnormal pump vibration or noise, inability to start the pump normally, decreased volumetric efficiency, abnormal pump pressure fluctuations, leakage of working medium, and excessively high pump body temperature. These failures primarily affect the pump's sealing performance, heating characteristics, and output flow capacity. Therefore, it is necessary to conduct pre-test performance tests, high-speed tests, full-load tests, operating condition tests, high-temperature tests, and low-temperature tests, as well as sealing and pump body temperature checks during the tests, and post-test performance tests.

[0063] The pre-test and post-test performance tests use the screw pump's volumetric efficiency and rated output flow rate as two key evaluation criteria to compare performance changes before and after the screening test, eliminating defective or unqualified products. High-speed and full-load tests initially tighten the operating conditions of the tested pump's friction pairs, further screening their wear resistance. Operating condition tests assess the tested pump's functional performance. High-temperature tests evaluate the performance of the seals and the quality and manufacturability of the materials used in each moving friction pair under low oil viscosity conditions. Low-temperature tests evaluate the performance of the seals and the fitting accuracy of each moving friction pair under high oil viscosity conditions. Sealing performance and pump body temperature checks are performed during these tests to examine the screw pump's sealing characteristics and the heating characteristics of the friction pairs. After completing the above tests, performance testing is conducted to verify the changes in the screw pump's efficiency and output flow rate after screening and evaluation. The specific steps are as follows:

[0064] A. Pre-test performance test: The purpose of this test is to check whether the basic output flow capacity of the screw pump meets the requirements and to compare it with the data after the screening test. This includes volumetric efficiency characteristic test and rated flow characteristic test. The specific test steps are as follows: Install the screw pump under test; start the test bench and load it; control the oil temperature within the actual operating oil temperature range and conduct the test in 20℃ increments; adjust the input shaft speed of the screw pump under test and gradually increase it to the rated speed, i.e., 1450 rpm; after the speed stabilizes, increase the outlet pressure of the screw pump under test to the rated pressure in steps, and run it stably for 2 minutes at each pressure step. Collect the inlet flow and outlet flow of the screw pump under test at each pressure step, and calculate whether the rated output flow and volumetric efficiency at the rated pressure meet the requirements according to "JB / T 8091-1998 Screw Pump Test Method"; repeat the test in another temperature step range.

[0065] B. High-speed test: The purpose is to verify whether the performance of the screw pump still meets the requirements after running at high speed. The specific test steps are as follows: Install the screw pump under test; start the test bench and load it; control the oil temperature within the actual operating oil temperature range; maintain the screw pump inlet pressure ≤0.2MPa; adjust the input shaft speed of the screw pump under test, gradually increasing it to 115% of the rated speed; after the speed stabilizes, gradually increase the outlet pressure of the screw pump under test to the rated pressure; stabilize the condition and run continuously for 2 hours.

[0066] C. Full-load test: The purpose is to examine the performance degradation of the screw pump under short-term full-load operation. The specific test steps are as follows: Install the screw pump under test; start the test bench and load it; control the oil temperature within the actual operating oil temperature range; adjust the input shaft speed of the screw pump under test and gradually increase it to the rated speed; after the speed stabilizes, increase the outlet pressure of the screw pump under test to the maximum working pressure in steps, and run it stably for 2 minutes for each pressure step, repeating 15 times.

[0067] D. Operating condition test: The purpose is to verify that the screw pump operates normally under the actual operating load spectrum and that all technical indicators of the screw pump meet the requirements. The specific test steps are as follows: Install the screw pump under test; start the test bench and load it; control the oil temperature within the actual operating oil temperature range; adjust the input shaft speed of the screw pump under test and gradually increase it to the rated speed; after the speed stabilizes, increase the outlet pressure of the screw pump under test to the rated pressure in a stepwise manner, and run stably for 10 minutes for each pressure step (refer to the shortest time for the test pressure point in "JB / T8091-1998 Screw Pump Test Method"), and repeat 5 times.

[0068] E. High temperature test: The purpose is to verify that the screw pump operates normally in a high temperature environment. The test pump is operated at rated speed and rated pressure, with an ambient temperature of 50±5℃ (the upper limit of the equipment temperature requirement), and the oil viscosity is not lower than the minimum allowable viscosity of the test pump, according to the working condition test load.

[0069] F. Low temperature test: The purpose is to verify the starting characteristics of the screw pump in a low temperature environment. The ambient temperature is -25℃ to 0℃ (the starting temperature required by the equipment), the oil viscosity is not lower than the minimum allowable viscosity of the pump under test, and the screw pump can start normally.

[0070] G. Sealing performance inspection: The purpose is to check the oil leakage of the screw pump during the entire test operation. The specific test steps are as follows: Before conducting the high-speed test, full-load test, and operating condition test, wipe the pump under test clean with oil-absorbing cotton. If some parts cannot be cleaned cleanly in one go and "false" leakage occurs after operation, it is allowed to clean them again. During the test, oil-absorbing cotton is placed under the screw pump under test. After the high-speed test, full-load test, and operating condition test, observe the oil stains on the oil-absorbing cotton placed underneath. Wipe the pump body with clean oil-absorbing cotton and observe the oil stains on the oil-absorbing cotton. No fine oil stains should be visible.

[0071] H. Pump body temperature check: The purpose is to check the heating of the screw pump friction pair during the entire test run. The pump body temperature should be measured regularly using an infrared thermometer. The pump body temperature should not rise rapidly in a short period of time, and the temperature should not exceed 90℃ throughout the entire process.

[0072] I. Post-test performance test: The purpose of this test is to check whether the output flow capacity of the screw pump meets the requirements after the screening test. This includes volumetric efficiency characteristic test and rated flow characteristic test. The specific test steps are the same as those of the pre-test performance test.

[0073] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0074] 1. Based on the common faults of axial piston pumps, this invention proposes scientific and reasonable test judgment methods and judgment criteria for each fault, and designs and proposes for the first time a screening test method for axial piston pumps used in underwater acoustic equipment.

[0075] 2. The screening test method for axial piston pumps can conduct preliminary screening of early problems in the production and assembly of piston pumps, which is helpful in grasping the consistency and stability of product performance, and can be used as a reference for other piston pump products.

[0076] 3. The screw pump screening test method described in this invention, combined with the operating environment of the screw pump, adds high-speed test, full-load test and working condition test. It aims to eliminate defective and unqualified products through non-destructive short-term performance test and extreme working condition test before installation, screen out qualified products that meet the requirements of important host equipment, establish a screw pump installation access method, and reduce the risk of screw pump use throughout its entire life cycle. Attached Figure Description

[0077] Figure 1 This is a flowchart of the axial piston pump test of the present invention;

[0078] Figure 2 This is a waveform diagram of the impact of an axial piston pump.

[0079] Figure 3 A constant power characteristic curve of an axial piston pump;

[0080] Figure 4 This is a flowchart of the screw pump screening test steps in this invention;

[0081] Figure 5 This is the high-speed test load spectrum curve for the screw pump screening test developed in this invention;

[0082] Figure 6 This is the full-load test load spectrum curve for the screw pump screening test developed in this invention;

[0083] Figure 7 This refers to the load spectrum curve of the working condition test in the screw pump screening test as defined in this invention;

[0084] Figure 8 This invention provides the criteria for determining the selection of screw pumps in the screening test. Detailed Implementation

[0085] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0086] Example 1: Refer to Table 1. Table 1 lists common faults, failure modes, causes, and effects of axial piston pumps. In this example, the faults that occur during the use of the axial piston pump are varied and can be mainly divided into: copper plating and burning on the distributor plate; cracking and peeling of the sintered layer in the bimetallic cylinder block; copper plating and burning on the swashplate; slipper slippage, slippage, uneven wear or severe wear; severe wear of the return plate; damage to the return plate, etc.; piston seizing the cylinder bore; seal failure; breakage of variable displacement mechanism parts, spline damage, etc.; burning of sliding bearings; damage to rolling bearings (pitting of rolling parts).

[0087] See Figure 1 As one embodiment of the present invention, common faults of axial piston pumps are first analyzed. Further, for axial piston pump failure faults, the following tests need to be carried out: efficiency characteristic test, high temperature test, low temperature test, impact test, overload test, and overspeed large displacement test. After the tests, variable characteristic test, efficiency characteristic retest, and sealing performance check are performed.

[0088] The test method for efficiency characteristics is as follows:

[0089] a) At maximum displacement and rated speed (1500 rpm), gradually increase the outlet pressure of the pump under test to 25% of the rated pressure (8.75 MPa), run under this condition for no less than 10 minutes, and wait for the test state to stabilize.

[0090] b) Using the above method, gradually increase the outlet pressure of the pump under test to the rated pressure (35MPa). This pressurization process should not be less than 25 minutes. When the pump under test is at the rated pressure (35MPa) and the speed is at the rated speed (1500rpm), measure the output flow rate of the pump under test when the ambient temperature is 20℃~35℃ and 50℃~60℃ respectively.

[0091] c) With the pump under test in no-load condition and at its rated speed (1500 rpm), measure the output flow rate of the pump under test at ambient temperatures of 20℃~35℃ and 50℃~60℃ respectively.

[0092] d) Calculate the volumetric efficiency and overall efficiency, with the following requirements: volumetric efficiency ≥ 92% and overall efficiency 87%.

[0093] e) Stop the pump under test and prepare for the next high-temperature test.

[0094] The test method for high temperature testing is as follows:

[0095] a) Start the pump under test and gradually increase the pressure to the rated pressure (35MPa). The pressurization process should not be less than 25 minutes.

[0096] b) Run the pump under test continuously for more than 1 hour at the rated speed (1500 rpm) and rated pressure (35 MPa), with an ambient temperature of 50°C and an oil viscosity not lower than the minimum allowable viscosity of the pump under test.

[0097] c) Stop the pump under test and prepare for the next low-temperature test.

[0098] The test method for low temperature testing is as follows:

[0099] a) With the pump under test at no load, rated speed (1500 rpm), zero displacement, and ambient temperature of -25℃, use L-HV type low temperature anti-wear hydraulic oil and start the pump under test at least five times.

[0100] b) With the pump under test at no load, rated speed (1500 rpm), 0.5 times the maximum displacement, and an ambient temperature of -25℃, use L-HV type low temperature anti-wear hydraulic oil and start the pump under test at least five times.

[0101] The test method for impact testing is as follows:

[0102] a) The pump under test was subjected to 500 impacts at rated speed (1500 rpm) with a high pressure of 35 MPa and a low pressure of 10 MPa, using a square wave frequency of 0.1 Hz. The waveform is as follows. Figure 2 As shown. During the experiment, the temperature was controlled between 25℃ and 40℃;

[0103] b) Stop the pump under test and prepare for the next step of the high-speed, high-displacement test.

[0104] The test method for high-speed, large-displacement engine tests is as follows:

[0105] a) Run the pump under test continuously at its maximum speed (1700 rpm) under no-load for at least 15 minutes. The ambient temperature during the test should be between 25℃ and 40℃.

[0106] b) The pump under test shall be pressurized stepwise to the rated pressure (35MPa), and the pressurization process shall not be less than 25 minutes.

[0107] c) Run the pump under test continuously for more than 15 minutes at a speed of 1500 rpm, maximum displacement, and pressure of 35 MPa. During the test, the ambient temperature is controlled between 25℃ and 40℃.

[0108] The test method for overload testing is as follows:

[0109] a) The pump under test is pressurized stepwise to the peak pressure (40MPa), and the pressurization process should not be less than 30 minutes;

[0110] b) Under rated speed (1500 rpm) and peak pressure (40 MPa) conditions, operate continuously for more than 1 minute, with the ambient temperature controlled between 25℃ and 40℃. Check for any noise, abnormal vibration, or other abnormal phenomena.

[0111] c) Stop the test pump and prepare for the next variable characteristic test.

[0112] The experimental method for variable characteristic testing is as follows:

[0113] a) Determination of the minimum pressure switching point: Adjust the variable mechanism to bring the pump under test to the minimum pressure switching state and measure the outlet pressure of the pump under test;

[0114] b) Determination of the highest pressure switching point: Adjust the variable mechanism to bring the tested pump to the highest pressure switching state and measure the pump outlet pressure;

[0115] c) Determination of constant power characteristics: Adjust the variable mechanism according to design requirements, measure the corresponding data for pressure and flow rate, and plot the constant power characteristic curve (pressure-flow characteristic curve), such as... Figure 3 As shown.

[0116] d) Stop the test pump and prepare for the next step of efficiency characteristic retesting.

[0117] After completing the above tests, the efficiency characteristics were retested. The retesting method is as follows:

[0118] a) At maximum displacement and rated speed (1500 rpm), gradually increase the outlet pressure of the pump under test to 25% of the rated pressure (8.75 MPa), run under this condition for no less than 10 minutes, and wait for the test state to stabilize.

[0119] b) Following the above method, gradually increase the outlet pressure of the pump under test to the rated pressure (35MPa). This pressurization process should not be less than 25 minutes. When the pump under test is at the rated pressure (35MPa) and the speed is at the rated speed (1500rpm), measure the output flow rate of the pump under test at ambient temperatures of 20℃~35℃ and 50℃~60℃ respectively, and record the measured data in Table A.3.

[0120] c) With the pump under test in no-load condition and at the rated speed (1500 rpm), measure the output flow rate of the pump under test when the ambient temperature is 20℃~35℃ and 50℃~60℃ respectively, and record the measured data in Table A.4.

[0121] d) Calculate the volumetric efficiency and overall efficiency.

[0122] e) Stop the pump under test and prepare for the next step of sealing performance inspection.

[0123] The test method for checking sealing performance is as follows:

[0124] Clean the pump under test. If some parts cannot be cleaned completely in one go, and a "false" leak occurs after operation, it is permissible to clean them again. After the pump stops running, press clean absorbent paper onto the static seal area, then remove it and check if there are oil droplets on the absorbent paper. If there are oil stains on the paper, it indicates a leak; if no oil stains are found, the seal is normal.

[0125] Using experimental data and the following formulas, the relevant performance indicators of the axial piston pump were calculated.

[0126] Furthermore, after completing the above tests, axial piston pumps with significant performance changes after a series of tests and those exhibiting abnormal vibration and noise during the tests were excluded. The qualification criteria for the tested pumps were determined as follows: (1) the volumetric efficiency and total efficiency of the tested pumps changed by no more than ±1.5% compared to the first test; (2) there was no abnormal vibration and noise during the test. If the test sample did not meet either of the above two criteria, it was considered to be eliminated in the screening test.

[0127] After all the above tests meet the test requirements, the axial piston pump is deemed to have passed the screening test.

[0128]

[0129]

[0130] Table 1

[0131] Example 2: This example discloses a screening test method for screw pumps used in sonar equipment. By analyzing the main failure modes of the screw pump, the test items are confirmed. The main failure modes of the screw pump are: insufficient pump output flow, insufficient pump pressure build-up capacity, abnormal pump vibration or noise, pump failure to start normally, decreased volumetric efficiency, abnormal pump pressure fluctuation, leakage of working medium, and excessively high pump body temperature. These mainly manifest in the pump's sealing performance, heating characteristics, and output flow capacity, thereby determining the appropriate testing methods. Figure 4 The flowchart shown in this example illustrates the screening test method for screw pumps. The order of the high-speed test, full-load test, and operating condition test can be adjusted appropriately. Specifically, it includes:

[0132] A. Performance testing before and after the test: The purpose of the test is to check whether the basic output flow capacity of the screw pump meets the requirements, including volumetric efficiency characteristic test and rated flow characteristic test. The specific test steps are as follows: Install the screw pump under test; start the test bench and load it; control the oil temperature within the actual operating oil temperature range, and conduct the test in 20°C increments, i.e., 20-40°C and 40-60°C; adjust the oil temperature to 20-40°C; adjust the input shaft speed of the screw pump under test, gradually increasing it to the rated speed, i.e., 1450 rpm; after the speed stabilizes, increase the outlet pressure of the screw pump under test to the rated pressure of 2MPa in steps, and run it stably for 2 minutes at each pressure step. Collect the inlet flow and outlet flow of the screw pump under test at each pressure step, and calculate the rated output flow and volumetric efficiency at the rated pressure according to "JB / T 8091-1998 Screw Pump Test Method" to see if they meet the requirements; repeat the above test in the oil temperature range of 40-60°C.

[0133] B. High-speed test: The purpose is to verify whether the screw pump performance still meets the requirements after high-speed operation. The specific test steps are as follows: Install the screw pump under test; start the test bench and load it; control the oil temperature within the actual operating oil temperature range; maintain the screw pump inlet pressure ≤ 0.2 MPa; adjust the input shaft speed of the screw pump under test, gradually increasing it to 110% of the rated speed, i.e., 1450 rpm × 115% = 1667.5 rpm; after the speed stabilizes, gradually increase the screw pump outlet pressure to the rated pressure of 2 MPa; stabilize the state and run continuously for 2 hours. The load spectrum is as follows: Figure 5 As shown.

[0134] C. Full-load test: The purpose is to examine the performance degradation of the screw pump under short-term full-load operation. The specific test steps are as follows: Install the screw pump under test; start the test bench and load it; control the oil temperature within the actual operating oil temperature range; adjust the input shaft speed of the screw pump under test, gradually increasing it to the rated speed, i.e., 1450 rpm; after the speed stabilizes, increase the outlet pressure of the screw pump under test to the maximum working pressure of 8 MPa in a stepwise manner, with each pressure step running stably for 2 minutes, repeated 15 times. The load spectrum is as follows. Figure 6 As shown.

[0135] D. Operating condition test: The purpose is to verify that the screw pump operates normally under the actual operating load spectrum and that all technical indicators of the screw pump meet the requirements. The specific test steps are as follows: Install the screw pump under test; start the test bench and load it; control the oil temperature within the actual operating oil temperature range; adjust the input shaft speed of the screw pump under test, gradually increasing it to the rated speed, i.e., 1450 rpm; after the speed stabilizes, increase the outlet pressure of the screw pump under test to the rated pressure in a stepwise manner, with each pressure step running stably for 10 minutes, repeated 5 times. The load spectrum is as follows: Figure 7 As shown.

[0136] E. High temperature test: The purpose is to verify that the screw pump operates normally in a high temperature environment. The test pump is operated at rated speed and rated pressure, with an ambient temperature of 50±5℃ and the oil viscosity not lower than the minimum allowable viscosity of the test pump, according to the working condition test load.

[0137] F. Low temperature test: The purpose is to verify the starting characteristics of the screw pump in a low temperature environment. The ambient temperature is (-25℃ to 0℃), the oil viscosity is not lower than the minimum allowable viscosity of the pump under test, and the screw pump can start normally.

[0138] G. Sealing performance inspection: The purpose is to check the oil leakage of the screw pump during the entire test operation. The specific test steps are as follows: Before conducting the high-speed test, full-load test, and operating condition test, wipe the pump under test clean with oil-absorbing cotton. If some parts cannot be cleaned cleanly in one go and "false" leakage occurs after operation, it is allowed to clean them again. During the test, oil-absorbing cotton is placed under the screw pump under test. After the high-speed test, full-load test, and operating condition test, observe the oil stains on the oil-absorbing cotton placed underneath. Wipe the pump body with clean oil-absorbing cotton and observe the oil stains on the oil-absorbing cotton. No fine oil stains should be visible.

[0139] H. Pump body temperature check: The purpose is to check the heating of the screw pump friction pair during the entire test run. The pump body temperature should be measured regularly using an infrared thermometer. The pump body temperature should not rise rapidly in a short period of time, and the temperature should not exceed 90℃ throughout the entire process.

[0140] I. Post-test performance test: The purpose of this test is to check whether the output flow capacity of the screw pump meets the requirements after the screening test. This includes volumetric efficiency characteristic test and rated flow characteristic test. The specific test steps are the same as those of the pre-test test.

[0141] like Figure 8 As shown, the criteria for passing the screw pump screening test should include the following aspects: 1. The screw pump has no oil leakage during the entire process of high-speed test, full-load test, working condition test, high and low temperature test and performance test before and after the test, and the pump body temperature does not exceed 90℃; 3. Considering the influence of oil temperature, the deviation between the rated output flow and volumetric efficiency of the screw pump and the design value after the test does not exceed 3%.

[0142] It is understood that, for those skilled in the art, any equivalent substitutions or modifications to the technical solutions and inventive concepts of this invention should fall within the scope of protection of the appended claims.

Claims

1. A method for screening test of a hydraulic pump for underwater acoustic equipment, characterized by: First, the common faults of hydraulic pump are analyzed, and then based on the above common faults, the screening test method is proposed, and the corresponding test is carried out; after completing all the above tests, the performance test is carried out; finally, the data processing and test result judgment are carried out; The hydraulic pump is an axial piston pump, specifically including the following steps: A, first, analyze the common faults of the axial piston pump, including copper hanging, burn, bimetallic cylinder body sintering layer cracking, falling off; copper hanging, burn, sliding shoe loose, off shoe, uneven wear or serious wear, severe wear of return disc, broken return disc; piston biting cylinder hole; seal failure; variable mechanism part breakage, spline damage; sliding bearing burn, rolling bearing damage; B, then based on the above common faults, the axial piston pump screening test method is proposed, and the test includes efficiency characteristic test, high temperature test, low temperature test, impact test, overspeed large displacement test and overload test; C, finally, after completing all the above tests, the variable characteristic test, efficiency characteristic retest and sealing performance check of the test pump are carried out to exclude the axial piston pump with large performance change after a series of tests and abnormal vibration and noise during the test; The test pump is qualified according to the following criteria: (1) the volumetric efficiency and total efficiency of the test pump change by no more than ±1.5% compared with the first test; (2) no abnormal vibration and noise during the test; if the test sample does not meet any of the above two criteria, it is considered to be eliminated in the screening test.

2. The hydraulic pump screening test method for underwater acoustic equipment according to claim 1, characterized by: The test method of the efficiency characteristic test is as follows: a) gradually increase the outlet pressure of the test pump to 25% of the rated pressure at the maximum displacement and rated speed, and measure the data related to the efficiency after the test state is stable; b) according to the above method, when the outlet pressure of the test pump is the rated pressure and the speed is the rated speed, measure the output flow of the test pump when the ambient temperature is 20-35℃ and 50-60℃ respectively; c) when the test pump is in an idle state, measure the output flow of the test pump when the ambient temperature is 20-35℃ and 50-60℃ respectively at the rated speed; d) calculate the volumetric efficiency and total efficiency; The test method of the high temperature test is as follows: make the test pump run continuously for more than 1h at the rated speed and rated pressure, with an ambient temperature of 50±5℃ and an oil viscosity not lower than the minimum allowed by the test pump; The test method of the low temperature test is as follows: put the whole test bench into a low temperature box; a) start the test pump at least five times at an idle state, rated speed and zero displacement, with an ambient temperature of-25℃ and low temperature wear-resistant hydraulic oil; b) start the test pump at least five times at an idle state, rated speed and 0.5 times maximum displacement, with an ambient temperature of-25℃ and low temperature wear-resistant hydraulic oil; The test method of the impact test is as follows: make the test pump perform 500 times of impact at a rated speed, with high pressure 35MPa, low pressure 10MPa and square wave frequency 0.1Hz, and the temperature is controlled at 25-40℃ during the test; The test method of the overspeed large displacement test is as follows: a) the test pump is continuously operated at the highest rotating speed and no load for more than 15 minutes, and the ambient temperature during the test is 25-40 DEG C; if no abnormal heating and noise occur, the next test is performed; b) the rotating speed is restored to the rated rotating speed, and the specific test scheme is: continuously operating for more than 15 minutes at the rated rotating speed, maximum displacement and pressure of 35 MPa, and the ambient temperature during the test is controlled at 25-40 DEG C; The test method of the overload test is as follows: continuously operating for more than 1 minute at the rated rotating speed and peak pressure, and the ambient temperature is controlled at 25-40 DEG C, and the abnormal phenomena are checked.

3. The hydraulic pump screening test method for underwater acoustic equipment according to claim 1, characterized by: The test method of the variable characteristic test is as follows: a) determination of the minimum pressure switching point: adjusting the variable mechanism to make the test pump in the minimum pressure switching state to measure the outlet pressure of the test pump; b) determination of the maximum pressure switching point: adjusting the variable mechanism to make the test pump in the maximum pressure switching state to measure the outlet pressure of the pump; c) determination of the constant power characteristic: adjusting the variable mechanism according to the design requirements, measuring the corresponding data of pressure and flow, and drawing the constant power characteristic curve, i.e. the pressure-flow characteristic curve.

4. The hydraulic pump screening test method for underwater acoustic equipment according to claim 1, characterized by: The efficiency characteristic retest method is as follows: a) at the maximum displacement and rated rotating speed, the outlet pressure of the test pump is gradually increased to 25% of the rated pressure, and after the test state is stable, the data related to the efficiency are measured; b) according to the above method, when the outlet pressure of the test pump is the rated pressure and the rotating speed is the rated rotating speed, the output flow is measured respectively when the inlet oil temperature of the test pump is 20-35 DEG C and 50-60 DEG C; c) when the test pump is in the no load state and the rotating speed is the rated rotating speed, the output flow is measured respectively when the inlet oil temperature of the test pump is 20-35 DEG C and 50-60 DEG C; d) the volumetric efficiency and total efficiency are calculated.

5. A method for screening test of a hydraulic pump for underwater acoustic equipment, characterized by: Firstly, common faults of the hydraulic pump are analyzed, and then based on the above common faults, the screening test method is proposed, and the corresponding test is carried out; after all the above tests are completed, the performance test is carried out; finally, the data processing and test result judgment are carried out; The hydraulic pump is a screw pump, and the specific steps are as follows: A, firstly, common faults of the screw pump are analyzed, including insufficient pump output flow, insufficient pump pressure building capacity, abnormal vibration or noise of the pump, failure of the pump to start normally, decrease of the volumetric efficiency, abnormal fluctuation of the pump pressure, leakage of the working medium, and excessive temperature of the pump body, mainly in the pump sealing performance, heating characteristics and output flow capacity; B, then based on the above common faults, the screening test method of the screw pump is proposed, and the performance test before test, high speed test, full load test, working condition test, high temperature test and low temperature test are carried out for the failure faults of the screw pump; C, during the above tests, the sealing performance and pump body temperature are checked, and after all the above tests are completed, the performance test is carried out, and the screw pump with good performance is screened out through non-destructive test before use, and the service performance of the screw pump in the whole life cycle is predicted through short-term performance test and extreme working condition test. The screw pump screening test shall include the following aspects by judging criteria: the screw pump has no oil leakage in the whole process of high-speed test, full load test, working condition test, high-low temperature test and performance test before and after the test, and the temperature of the pump body is not more than 90 DEG C; considering the influence of oil temperature, the deviation of the rated output flow and volumetric efficiency of the screw pump after the test from the design value is not more than 3%.

6. The hydraulic pump screening test method for underwater acoustic equipment according to claim 5, characterized by: The performance test before the test checks whether the basic output flow capacity of the screw pump meets the requirements, and compares the data after the screening test, including volumetric efficiency characteristic test and rated flow characteristic test, and the specific test steps are as follows: installing the screw pump to be tested; starting the test bench loading; controlling the oil temperature in the actual use oil temperature range, and carrying out the test according to 20 DEG C ladder; adjusting the input shaft speed of the screw pump to be tested, and gradually increasing to the rated speed; After the speed is stable, the outlet pressure of the screw pump to be tested is increased step by step to the rated pressure, each pressure step is stably operated for 2 minutes, the inlet flow and outlet flow of the screw pump to be tested under each step pressure are collected, and whether the rated output flow and volumetric efficiency at the rated pressure meet the requirements are calculated; the test is repeated in another temperature step range.

7. The hydraulic pump screening test method for underwater acoustic equipment according to claim 5, characterized by: The high-speed test checks whether the performance of the screw pump can still meet the requirements after running at high speed, and the specific test steps are as follows: installing the screw pump to be tested; starting the test bench loading; controlling the oil temperature in the actual use oil temperature range; keeping the inlet pressure of the screw pump ≤0.2 MPa; adjusting the input shaft speed of the screw pump to be tested, and gradually increasing to 115% of the rated speed; After the speed is stable, the outlet pressure of the screw pump to be tested is gradually increased to the rated pressure; the state is stabilized, and the continuous operation is 2 hours; The full load test checks the performance degradation of the screw pump under short time full load operation, and the specific test steps are as follows: installing the screw pump to be tested; starting the test bench loading; controlling the oil temperature in the actual use oil temperature range; adjusting the input shaft speed of the screw pump to be tested, and gradually increasing to the rated speed; After the speed is stable, the outlet pressure of the screw pump to be tested is increased step by step to the highest working pressure, each pressure step is stably operated for 2 minutes, and the cycle is 15 times; The working condition test checks whether the screw pump can run normally under the actual use load spectrum, and whether the technical indexes of the screw pump meet the requirements, and the specific test steps are as follows: installing the screw pump to be tested; starting the test bench loading; controlling the oil temperature in the actual use oil temperature range; adjusting the input shaft speed of the screw pump to be tested, and gradually increasing to the rated speed; After the speed is stable, the outlet pressure of the screw pump to be tested is increased step by step to the rated pressure, each pressure step is stably operated for 10 minutes, and the cycle is 5 times; The high temperature test checks whether the screw pump can run normally under high temperature environment, so that the test pump can run under the conditions of rated speed and rated pressure, environment temperature of 50±5 DEG C, and oil viscosity not less than the minimum viscosity allowed by the test pump; and the load is operated according to the working condition test; The low temperature test checks the starting characteristics of the screw pump under low temperature environment, the environment temperature is-25 DEG C-0 DEG C, the oil viscosity is not less than the minimum viscosity allowed by the test pump, and the screw pump can start normally.

8. The hydraulic pump screening test method for underwater acoustic equipment according to claim 5, characterized by: The sealing performance inspection inspects the oil leakage of the screw pump during the whole test operation, and the specific test steps are as follows: before the high-speed test, full load test and working condition test, the test pump is wiped clean with oil absorbing cotton, and the oil absorbing cotton is laid under the test screw pump during the test; after the high-speed test, full load test and working condition test, the oil stain of the oil absorbing cotton laid under is observed, and the pump body is wiped with clean oil absorbing cotton to observe the oil stain of the oil absorbing cotton, and no obvious oil stain appears.

9. The hydraulic pump screening test method for underwater acoustic equipment according to claim 5, characterized by: The pump body temperature inspection inspects the heating of the friction pair of the screw pump during the whole test operation, and the infrared temperature measuring instrument is used to measure the pump body temperature regularly, and the pump body temperature cannot rise rapidly in a short time, and the whole process temperature does not exceed 90°C.

Images