A closed system for high pressure high flow resistance testing and method of use thereof

Abstract

The application provides a closed system for high-pressure and large-flow resistance test and a use method thereof, relates to the field of flow resistance test, and comprises a temperature control liquid storage unit, a closed test unit, an auxiliary unit and a recovery unit. The closed test unit is used for measuring the pressure difference between the two ends of a test piece, the pressure of the input end of the test piece, the flow of the test piece and the working temperature of the test piece. The recovery unit is used for recovering the oil liquid in the test piece after the test. The temperature control liquid storage unit delivers the oil liquid with heat to the closed test unit through the auxiliary unit. The closed test unit discharges the oil liquid to the temperature control liquid storage unit through the auxiliary unit. The auxiliary unit is used for pressurizing the closed test unit and controlling the temperature of the closed test unit. The closed test unit can be selected to have a low-power consumption, the auxiliary unit can be selected to have a low-power consumption, the operation cost is low, the energy-saving effect is good, less liquid is required for the test, the heating and cooling power of the system is reduced, and the manufacturing cost is low.

Description

Technical Field

[0001] This invention relates to the field of flow resistance testing technology, and in particular to a closed system for high-pressure, high-flow-resistance testing and its usage method. Background Technology

[0002] The current industry standard, GB / T 17486-2006 "Evaluation of Pressure Drop and Flow Characteristics of Hydraulic Filters," is used for product flow resistance testing. Existing testing systems are open-loop systems.

[0003] In existing technologies, the pressure of the test product is controlled by a regulating valve at the rear of the test product, and the pressure is provided by a test pump. This requires a high-pressure, high-flow-rate test pump, which demands a great deal of power. Since open-type testing requires an oil tank and a large amount of test fluid, the heating and cooling power required by the open-type testing system is extremely high, resulting in high manufacturing costs. Summary of the Invention

[0004] To address the technical problems existing in the prior art, embodiments of the present invention provide a closed-loop system for high-pressure, high-flow-resistance testing and its usage method. The technical solution is as follows:

[0005] A closed-loop system for high-pressure, high-flow-resistance testing includes a temperature-controlled reservoir unit, a closed-loop testing unit, an auxiliary unit, and a recovery unit. The closed-loop testing unit measures the pressure difference across the test specimen, the input pressure of the test specimen, the flow rate of the test specimen, and the operating temperature of the test specimen. The recovery unit recovers the oil from the test specimen after testing. The temperature-controlled reservoir unit supplies heated oil to the closed-loop testing unit through the auxiliary unit. The closed-loop testing unit discharges oil to the temperature-controlled reservoir unit through the auxiliary unit. The auxiliary unit pressurizes the closed-loop testing unit and controls its temperature.

[0006] Optionally, the closed test unit includes a first branch and a second branch connected in parallel, as well as a third branch and a fourth branch connected in parallel. The first branch is connected in series with the third branch and the fourth branch, and the second branch is connected in series with the third branch. The first branch includes a main path and a first branch and a second branch connected in parallel. The main path is connected in series with the first branch and the second branch.

[0007] Optionally, an upstream manual switch valve, a product inlet pressure sensor, a test piece, and a downstream manual switch valve are sequentially connected from the input end to the output end of the main passage. A sampling valve is also provided on the main passage.

[0008] The first product differential pressure sensor is connected to the input and output terminals of the test piece, and the second product differential pressure sensor is connected to the input and output terminals of the test piece. Each input and output terminal of the test piece is connected to an exhaust solenoid valve. The output terminal of the first branch is connected to the input terminal of the main circuit, and the output terminal of the second branch is connected to the input terminal of the main circuit.

[0009] The first branch is equipped with a first pipeline flow meter and an electric switching valve in sequence from the input end to the output end, and the second branch is equipped with a second pipeline flow meter, a back pressure regulating valve and a solenoid valve in sequence from the input end to the output end.

[0010] Optionally, the second branch is provided with a bypass electric regulating valve, the third branch is provided with a frequency conversion test pump and a first filter in sequence from the input end to the output end, the first filter is connected to an oil drain valve, the fourth branch is provided with a high pressure pump inlet pressure sensor, a fixed frequency test pump and a check valve in sequence from the input end to the output end, and the main passage is provided with a temperature sensor.

[0011] Optionally, the auxiliary unit includes a temperature control branch, a pressurization branch, and a regulating branch. The input end of the pressurization branch is connected to the output end of the oil tank in the temperature-controlled liquid storage unit via an input pipeline. The pressurization branch is equipped with a drain valve and two variable frequency high-pressure pumps sequentially from the input end to the output end. The output end of the pressurization branch is connected to the input ends of the third and fourth branches, respectively. The temperature control branch is equipped with a temperature electric regulating valve. The input end of the temperature control branch is connected to the output end of the main circuit. The output end of the temperature control branch is connected to the input end of the oil tank via an output pipeline. The regulating branch is equipped with a bypass valve. The input end of the regulating branch is connected to the output end of the pressurization branch. The output end of the regulating branch is connected to the input end of the oil tank via an output pipeline.

[0012] Optionally, the recovery unit includes an oil collection tray, the output end of which is connected to the input end of a manual T-type three-way ball valve, the output end of which is connected to the input end of an oil guide pump, the output end of which is connected to the input end of a second filter, and the output end of the second filter is connected to the input end of an oil tank in the temperature-controlled liquid storage unit.

[0013] Optionally, the output end of the main passage is connected to the other input end of a manual T-type three-way ball valve via a maintenance pipeline.

[0014] A method for using a closed system for high-pressure, high-flow-resistance testing, comprising the closed test system described above for filter testing, the method comprising:

[0015] S1. Preset test flow rate, test pressure, and test temperature values;

[0016] S2. Open the oil tank in the temperature-controlled liquid storage unit and fill all pipelines in the closed test unit with oil through the pressurization branch of the auxiliary unit, and vent the air through the exhaust solenoid valve.

[0017] S3. Pressurize the closed test unit through the pressurization branch according to the preset test pressure value;

[0018] S4. Select the working pipeline according to the preset test flow rate value;

[0019] S5. Based on the preset test temperature value, the temperature of the closed test unit is controlled by observing the temperature sensor inside the closed test unit and through the temperature control branch.

[0020] S6. Read the data from the first product differential pressure sensor or the second product differential pressure sensor in the closed test unit, read the data from the product inlet pressure sensor in the closed test unit, read the data from the first pipeline flow meter or the second pipeline flow meter in the closed test unit, and read the data from the temperature sensor.

[0021] Optionally, in step S2, opening the oil tank in the temperature-controlled liquid storage unit to fill all pipelines in the closed test unit with oil through the pressurization branch of the auxiliary unit, and venting the oil through the exhaust solenoid valve includes:

[0022] Open the oil drain valve and two variable frequency high-pressure pumps on the pressurization branch in the auxiliary unit, open the variable frequency test pump on the third branch, open the bypass electric regulating valve on the second branch, open the solenoid valve on the second branch, open the upstream manual switch valve and the downstream manual switch valve on the main passage, and open the temperature electric regulating valve on the temperature control branch in the auxiliary unit.

[0023] Oil flows from the oil tank in the temperature-controlled storage unit into the pressurized branch and then into the input end of the variable frequency test pump. From the output end of the variable frequency test pump, the oil flows sequentially through the first filter on the third branch, the second pipeline flow meter on the second branch, the back pressure regulating valve and solenoid valve on the second branch, the upstream manual switch valve, the test piece, and the downstream manual switch valve. Part of the oil then passes through the temperature electric regulating valve and flows back to the oil tank through the output pipeline. The other part of the oil flows back to the input end of the variable frequency test pump. From the output end of the variable frequency test pump, the oil flows through the bypass electric regulating valve and then back to the input end of the variable frequency test pump. At this time, the oil fills the third branch, the second branch, the second branch, and the main passage.

[0024] Then open the fixed-frequency test pump on the fourth branch, the check valve on the fourth branch, and the electric switch valve on the first branch, and close the solenoid valve;

[0025] Part of the oil in the pressurization branch flows into the fixed frequency test pump, and then flows sequentially through the check valve, the first pipeline flow meter on the first branch, the electric switch valve, the upstream manual switch valve, the test piece and the downstream manual switch valve. Part of the oil then passes through the temperature electric regulating valve and flows back to the oil tank through the output pipeline. The other part of the oil flows back to the input end of the fixed frequency test pump.

[0026] Another portion of the oil in the pressurized branch flows into the input end of the variable frequency test pump. The oil flows from the output end of the variable frequency test pump sequentially through the first filter, the first pipeline flow meter, the electric switch valve, the upstream manual switch valve, the test piece, and the downstream manual switch valve. A portion of the oil then passes through the temperature electric regulating valve and flows back to the oil tank through the output pipeline, while the other portion flows back to the input end of the variable frequency test pump. The oil flows from the output end of the variable frequency test pump through the bypass electric regulating valve and then back to the input end of the variable frequency test pump. At this time, the first branch, the second branch, the third branch, and the fourth branch are filled with oil.

[0027] Adjust the two exhaust solenoid valves to exhaust air. When there are no more air bubbles in all pipelines within the closed test unit, the exhaust stops.

[0028] The step of applying pressure to the closed test unit through the pressurization branch according to the preset test pressure value in S3 includes:

[0029] Adjust the two variable frequency high-pressure pumps according to the preset test pressure value so that the data of the high-pressure pump inlet pressure sensor on the fourth branch is equal to the preset test pressure value.

[0030] Optionally, selecting the working pipeline according to the preset test flow rate value in step S4 includes:

[0031] When the preset test flow rate is less than or equal to the maximum flow rate of the variable frequency test pump but greater than or equal to the minimum flow rate of the variable frequency test pump, the fixed frequency test pump, bypass electric regulating valve and electric switching valve are closed, the variable frequency test pump is opened, and the flow rate of the variable frequency test pump is adjusted according to the preset test flow rate. The solenoid valve is opened, and the oil flows from the pressurization branch into the input end of the variable frequency test pump, and then flows from the output end of the variable frequency test pump through the second branch and the main passage in sequence. A part of the oil flows into the temperature control branch and then flows back to the oil tank, and the other part of the oil flows back to the input end of the variable frequency test pump.

[0032] When the preset test flow rate is less than the minimum flow rate of the variable frequency test pump, close the fixed frequency test pump and the electric switch valve, and open the bypass electric regulating valve, the variable frequency test pump and the solenoid valve so that the bypass electric regulating valve can pass the sum of the flow rate and the preset test flow rate equals the minimum flow rate of the variable frequency test pump.

[0033] Oil flows from the pressurization branch into the input end of the variable frequency test pump. From the output end of the variable frequency test pump, the oil flows sequentially through the second branch and the main passage. Part of the oil flows into the temperature control branch and then back to the oil tank, while the other part flows back to the input end of the variable frequency test pump. Additionally, oil flows from the output end of the variable frequency test pump through the bypass electric regulating valve and then back to the input end of the variable frequency test pump.

[0034] When the preset test flow rate value is greater than the maximum flow rate of the variable frequency test pump

[0035] At this time, the preset test flow rate is A, the maximum flow rate of the variable frequency test pump is B, the minimum flow rate of the variable frequency test pump is C, the flow rate of the fixed frequency test pump is D, and the flow rate of the bypass electric regulating valve is E.

[0036] When A=D, open the fixed frequency test pump and the electric switch valve, and close the variable frequency test pump, the bypass electric regulating valve and the solenoid valve.

[0037] Oil flows from the pressurization branch into the input end of the fixed frequency test pump. Oil flows from the output end of the fixed frequency test pump through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank. The other part of the oil flows back to the input end of the fixed frequency test pump.

[0038] When A is less than the sum of C and D, open the fixed frequency test pump, variable frequency test pump, electric switch valve and bypass electric regulating valve, and close the solenoid valve to make A = C + DE;

[0039] Oil flows from the pressurization branch into the input end of the fixed frequency test pump in part and into the input end of the variable frequency test pump in part. Oil flows from the output end of the fixed frequency test pump through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank. The other part of the oil flows back to the input end of the fixed frequency test pump.

[0040] Oil flows sequentially from the output of the variable frequency test pump through the first branch and the main passage. Part of the oil flows into the temperature control branch and then back to the oil tank, while the other part flows back to the input of the variable frequency test pump. Oil also flows from the output of the variable frequency test pump through the second branch and then back to the input of the variable frequency test pump.

[0041] When A is greater than or equal to the sum of C and D and less than or equal to the sum of B and D, open the fixed frequency test pump, variable frequency test pump and electric switch valve, close the bypass electric regulating valve and solenoid valve, and adjust the flow rate of the variable frequency test pump so that the flow rate of the variable frequency test pump is equal to the difference between A and D.

[0042] Oil flows from the pressurization branch into the input end of the fixed frequency test pump in part and into the input end of the variable frequency test pump in part. Oil flows from the output end of the fixed frequency test pump through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank. The other part of the oil flows back to the input end of the fixed frequency test pump.

[0043] Oil flows sequentially from the output of the variable frequency test pump through the first branch and the main passage. Part of the oil flows into the temperature control branch and then back to the oil tank, while the other part flows back to the input of the variable frequency test pump.

[0044] The step S5, which involves controlling the temperature of the closed test unit by observing the temperature sensor within the closed test unit and controlling the temperature through the temperature control branch based on a preset test temperature value, includes:

[0045] The system reads temperature sensor data. When the temperature sensor data is lower than the preset test temperature value, it increases the flow rate of the electric temperature regulating valve to quickly return cold oil to the oil tank, heat the oil in the tank, and then send it back to the closed test unit through the pressurization branch. When the temperature sensor data is higher than the preset test temperature value, it increases the flow rate of the electric temperature regulating valve to quickly return hot oil to the oil tank, cool the oil in the tank, and then send the cold oil to the closed test unit through the pressurization branch. When the temperature sensor data is equal to the preset test temperature value, it decreases the flow rate of the electric temperature regulating valve to keep the oil in the pipeline of the closed test unit warm.

[0046] The steps in S6, namely reading data from the first or second product differential pressure sensor within the closed-loop test unit, reading data from the product inlet pressure sensor within the closed-loop test unit, reading data from the first or second pipeline flow meter within the closed-loop test unit, and reading data from the temperature sensor, include:

[0047] When the solenoid valve is opened and the electric regulating valve is closed, the data of the second pipeline flow meter is read. When the electric switching valve is opened and the solenoid valve is closed, the data of the first pipeline flow meter is read. When the data of the first pipeline flow meter or the second pipeline flow meter and the temperature sensor are stable, the data of the first pipeline flow meter or the second pipeline flow meter are read according to the opening and closing status of the solenoid valve and the electric switching valve, the temperature sensor data is read, the data of the product inlet pressure sensor on the main channel is read, and the data of the first product differential pressure sensor is read. When the data of the first product differential pressure sensor reaches the maximum value of the range, the data of the second product differential pressure sensor is read.

[0048] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0049] 1. During product flow resistance testing, the flow resistance is typically between 0.15 bar and 0.4 bar, with minimal pressure difference. For closed-loop test units, low-pressure, high-flow-rate pumps can be used, resulting in extremely low power consumption. The product test pressure is provided by a static pressure auxiliary unit, which can also use high-pressure, low-flow-rate pumps, also with extremely low power consumption. Higher product test pressures and larger test flow rates are required. Compared to open-loop systems, less liquid is needed, resulting in lower operating costs and better energy savings.

[0050] 2. The test oil required for a closed-loop test unit depends on the system volume, not the test flow rate. This significantly reduces the amount of test oil needed, thereby greatly reducing the heating and cooling power of the auxiliary system. Higher test pressures and larger test flow rates are required for this type of product. Compared to open-loop systems, the manufacturing cost is lower. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a schematic diagram of a closed system for high-pressure, high-flow-resistance testing provided by the present invention.

[0053] Reference numerals: 1. Oil tank; 2. Variable frequency high-pressure pump; 3. Bypass valve; 4. High-pressure pump inlet pressure sensor; 5. Fixed frequency test pump; 6. Check valve; 7. First filter; 8. Drain valve; 9. Variable frequency test pump; 10. Bypass electric regulating valve; 11. Temperature sensor; 12. Sampling valve; 13. Second pipeline flow meter; 14. Solenoid valve; 15. Self-sealing quick connector; 16. Test specimen; 17. Manual switching valve; 18. Exhaust solenoid valve; 19. First product differential pressure sensor; 20. Second product differential pressure sensor; 21. Product inlet pressure sensor; 22. First pipeline flow meter; 23. Electric switching valve; 24. Back pressure regulating valve; 25. Temperature electric regulating valve; 26. Manual T-type three-way ball valve; 27. Oil pump; 28. Second filter. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0055] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising,” “including,” or “including,” and similar terms mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or “connected,” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0056] It should be noted that the terms "up", "down", "left", "right", "front", and "back" used in this invention are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0057] like Figure 1 As shown, a closed-loop system for high-pressure, high-flow-resistance testing is provided, comprising a temperature-controlled reservoir unit, a closed-loop testing unit, an auxiliary unit, and a recovery unit. The temperature-controlled reservoir unit includes an oil tank 1 and is capable of heating and cooling the oil tank 1; this is prior art and will not be described in detail here. The closed-loop testing unit is used to measure the pressure difference across the test specimen 16, the pressure at the input end of the test specimen 16, the flow rate input to the test specimen 16, and the operating temperature of the test specimen 16. The recovery unit is used to recover the oil in the test specimen 16 after the test. The temperature-controlled reservoir unit supplies oil with heat or cold to the closed-loop testing unit through the auxiliary unit. The closed-loop testing unit discharges oil to the temperature-controlled reservoir unit through the auxiliary unit. The auxiliary unit is used to pressurize the closed-loop testing unit and control the temperature of the closed-loop testing unit.

[0058] The closed test unit includes a first branch and a second branch connected in parallel, as well as a third branch and a fourth branch connected in parallel. The first branch is connected in series with the third branch and the fourth branch, respectively. The second branch is connected in series with the third branch. The first branch includes a main path and a first branch and a second branch connected in parallel. The main path is connected in series with the first branch and the second branch, respectively.

[0059] The main pathway is connected sequentially from its input to its output, including an upstream manual switch valve 17, a product inlet pressure sensor 21, a test specimen 16, and a downstream manual switch valve 17. A sampling valve 12 and a temperature sensor 11 are also provided on the main pathway. A first product differential pressure sensor 19 and a second product differential pressure sensor 20 are connected in parallel. The first product differential pressure sensor 19 is connected to the input and output of the test specimen 16 via self-sealing quick connectors 15, and the second product differential pressure sensor 20 is connected to the input and output of the test specimen 16 via self-sealing quick connectors 15. Each input and output of the test specimen 16 is connected to an exhaust solenoid valve 18. The output of the first branch is connected to the input of the main pathway, and the output of the second branch is also connected to the input of the main pathway.

[0060] The first branch line is equipped with a first pipeline flow meter 22 and an electric switching valve 23 sequentially from the input end to the output end. The second branch line is equipped with a second pipeline flow meter 13, a back pressure regulating valve 24, and a solenoid valve 14 sequentially from the input end to the output end. The back pressure regulating valve 24 is used to regulate the flow rate of the second branch line.

[0061] The second branch is equipped with a bypass electric regulating valve 10. The third branch, from input to output, is equipped with a frequency conversion test pump 9 and a first filter 7. The first filter 7 is connected to a drain valve 8. The first filter 7 is used to purify the oil flowing through the third branch. The drain valve 8 is used to remove the first filter 7 from the third branch during maintenance, thus draining any residual oil from the first filter 7. The fourth branch, from input to output, is equipped with a high-pressure pump inlet pressure sensor 4, a fixed-frequency test pump 5, and a check valve 6.

[0062] The auxiliary unit includes a temperature control branch, a pressurization branch, and a regulating branch. The input end of the pressurization branch is connected to the output end of the oil tank 1 in the temperature control liquid storage unit via an input pipeline. From the input end to the output end, the pressurization branch is equipped with a drain valve 8 and two variable frequency high-pressure pumps 2. Opening the drain valve 8 and the two variable frequency high-pressure pumps 2 allows oil to flow into the pressurization branch. The output end of the pressurization branch is connected to the input ends of the third and fourth branches, respectively. The temperature control branch is equipped with an electric temperature regulating valve 25. The input end of the temperature control branch is connected to the output end of the main circuit, and the output end of the temperature control branch is connected to the input end of the oil tank 1 via an output pipeline. The regulating branch is equipped with a bypass valve 3. The input end of the regulating branch is connected to the output end of the pressurization branch, and the output end of the regulating branch is connected to the input end of the oil tank 1 via an output pipeline.

[0063] The recovery unit includes an oil collection tray. The output of the oil collection tray is connected to the input of a manual T-type three-way ball valve 26. The output of the manual T-type three-way ball valve 26 is connected to the input of an oil transfer pump 27. The output of the oil transfer pump 27 is connected to the input of a second filter 28. The output of the second filter 28 is connected to the input of the oil tank 1 in the temperature-controlled liquid storage unit. The output of the main passage is connected to the other input of the manual T-type three-way ball valve 26 via a maintenance pipeline.

[0064] The function of the back pressure regulating valve 24 is to adjust the second branch flow rate to match the preset test flow rate when the preset test flow rate is too small, so that the second pipeline flow meter 13 can measure the required flow rate.

[0065] The function of the two manual switching valves 17 is to close the two manual switching valves 17 to prevent the liquid in the pipe from flowing into the test piece 16 when it is necessary to replace the test piece 16, so that the test piece 16 can be removed from the main passage. After the test piece 16 is removed, the residual liquid inside is poured into the oil collection pan, and from the oil collection pan it flows sequentially through the manual T-type three-way ball valve 26, the oil pump 27 and the second filter 28, and finally flows into the oil tank 1.

[0066] When the closed test unit needs to be repaired and the liquid in the closed test unit pipeline needs to be emptied, open the input end of the manual T-type three-way ball valve connected to the repair pipeline, so that the oil in the closed test unit flows through the first branch, through the repair pipeline, then into the manual T-type three-way ball valve 26, and finally into the oil tank 1. When the repair pipeline needs to be operated, the sampling valve 12 is opened to give the closed test unit an air inlet. Under the action of pressure, the oil flows into the repair pipeline and finally into the oil tank 1.

[0067] When the bypass valve 3 is opened, a portion of the oil in the pressurized branch flows into the regulating branch and then back to the oil tank 1 through the output pipeline. The bypass valve 3 is in the open state to prevent damage to the system from the inability to form a circuit in case of a malfunction of the temperature electric regulating valve 25.

[0068] A method for using a closed system for high-pressure, high-flow-resistance testing includes:

[0069] S1. Preset test flow rate, test pressure, and test temperature values;

[0070] S2. Open the oil tank 1 in the temperature control liquid storage unit and fill all the pipelines in the closed test unit with oil through the pressurization branch of the auxiliary unit, and exhaust the air through the exhaust solenoid valve 18.

[0071] Open the oil drain valve 8 and the two variable frequency high pressure pumps 2 on the pressurization branch in the auxiliary unit, open the variable frequency test pump 9 on the third branch, open the bypass electric regulating valve 10 on the second branch, open the solenoid valve 14 on the second branch, open the upstream manual switch valve 17 and the downstream manual switch valve 17 on the main passage, and open the temperature electric regulating valve 25 on the temperature control branch in the auxiliary unit.

[0072] Oil flows from the oil tank 1 in the temperature-controlled storage unit into the pressurized branch and then into the input end of the variable frequency test pump 9. From the output end of the variable frequency test pump 9, the oil flows sequentially through the first filter 7 on the third branch, the second pipeline flow meter 13 on the second branch, the back pressure regulating valve 24 on the second branch, the solenoid valve 14, the upstream manual switch valve 17, the test piece 16, and the downstream manual switch valve 17. Part of the oil then passes through the temperature electric regulating valve 25 and flows back to the oil tank 1 through the output pipeline. The other part of the oil flows back to the input end of the variable frequency test pump 9. From the output end of the variable frequency test pump 9, the oil flows through the bypass electric regulating valve 10 and then back to the input end of the variable frequency test pump 9. At this time, the oil fills the third branch, the second branch, the second branch, and the main passage.

[0073] Then open the fixed frequency test pump 5 on the fourth branch, the check valve 6 on the fourth branch, and the electric switch valve 23 on the first branch, and close the solenoid valve 14.

[0074] Part of the oil in the pressurized branch flows into the fixed-frequency test pump 5, and then flows sequentially through the one-way valve 6, the first pipeline flow meter 22 on the first branch, the electric switch valve 23, the upstream manual switch valve 17, the test piece 16, and the downstream manual switch valve 17. Part of the oil then passes through the temperature electric regulating valve 25 and flows back to the oil tank 1 through the output pipeline. The other part of the oil flows back to the input end of the fixed-frequency test pump 5.

[0075] Another portion of the oil in the pressurized branch flows into the input end of the variable frequency test pump 9. The oil flows from the output end of the variable frequency test pump 9 through the first filter 7, the first pipeline flow meter 22, the electric switch valve 23, the upstream manual switch valve 17, the test piece 16, and the downstream manual switch valve 17 in sequence. A portion of the oil then passes through the temperature electric regulating valve 25 and flows back to the oil tank 1 through the output pipeline. The other portion of the oil flows back to the input end of the variable frequency test pump 9. The oil flows from the output end of the variable frequency test pump 9 through the bypass electric regulating valve 10 and then flows back to the input end of the variable frequency test pump 9. At this time, the first branch, the second branch, the third branch, and the fourth branch are filled with oil.

[0076] Adjust the two exhaust solenoid valves 18 to exhaust air. When there are no air bubbles in any of the pipelines in the closed test unit, the exhaust stops.

[0077] S3. Pressurize the closed test unit through the pressurization branch according to the preset test pressure value;

[0078] Adjust the two variable frequency high-pressure pumps 2 according to the preset test pressure value so that the data of the high-pressure pump inlet pressure sensor 4 on the fourth branch is equal to the preset test pressure value.

[0079] S4. Select the working pipeline according to the preset test flow rate value;

[0080] When the preset test flow rate is less than or equal to the maximum flow rate of the variable frequency test pump 9 but greater than or equal to the minimum flow rate of the variable frequency test pump 9, the fixed frequency test pump 5, the bypass electric regulating valve 10 and the electric switching valve 23 are closed, the variable frequency test pump 9 is opened, and the flow rate of the variable frequency test pump 9 is adjusted according to the preset test flow rate. The solenoid valve 14 is opened, and the oil flows from the pressurization branch into the input end of the variable frequency test pump 9, and then flows from the output end of the variable frequency test pump 9 through the second branch and the main passage in sequence. A part of the oil flows into the temperature control branch and then flows back to the oil tank 1, and the other part of the oil flows back to the input end of the variable frequency test pump 9.

[0081] When the preset test flow rate is less than the minimum flow rate of the variable frequency test pump 9, the fixed frequency test pump 5 and the electric switch valve 23 are closed, and the bypass electric regulating valve 10, the variable frequency test pump 9 and the solenoid valve 14 are opened, so that the bypass electric regulating valve 10 can pass the sum of the flow rate and the preset test flow rate equals the minimum flow rate of the variable frequency test pump 9.

[0082] Oil flows from the pressurization branch into the input end of the variable frequency test pump 9. Oil flows from the output end of the variable frequency test pump 9 through the second branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank 1, while the other part of the oil flows back to the input end of the variable frequency test pump 9. Oil also flows from the output end of the variable frequency test pump 9 through the bypass electric regulating valve 10 and then back to the input end of the variable frequency test pump 9.

[0083] When the preset test flow rate value is greater than the maximum flow rate of the variable frequency test pump 9

[0084] At this time, the preset experimental flow rate is A, the maximum flow rate of the variable frequency test pump 9 is B, the minimum flow rate of the variable frequency test pump 9 is C, the flow rate of the fixed frequency test pump 5 is D, and the flow rate of the bypass electric regulating valve 10 is E.

[0085] When A=D, open the fixed frequency test pump 5 and the electric switch valve 23, and close the variable frequency test pump 9, the bypass electric regulating valve 10, and the solenoid valve 14.

[0086] Oil flows from the pressurization branch into the input end of the fixed frequency test pump 5. Oil flows from the output end of the fixed frequency test pump 5 through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank 1. The other part of the oil flows back to the input end of the fixed frequency test pump 5.

[0087] When A is less than the sum of C and D, open the fixed frequency test pump 5, the variable frequency test pump 9, the electric switch valve 23 and the bypass electric regulating valve 10, and close the solenoid valve 14, so that A = C + DE;

[0088] Oil flows from the pressurization branch into the input end of the fixed frequency test pump 5, and into the input end of the variable frequency test pump 9. Oil flows from the output end of the fixed frequency test pump 5 through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank 1, while the other part flows back to the input end of the fixed frequency test pump 5.

[0089] Oil flows from the output of the variable frequency test pump 9 through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank 1, while the other part flows back to the input of the variable frequency test pump 9. Oil also flows from the output of the variable frequency test pump 9 through the second branch and then back to the input of the variable frequency test pump 9.

[0090] When A is greater than or equal to the sum of C and D and less than or equal to the sum of B and D, open the fixed frequency test pump 5, the variable frequency test pump 9 and the electric switch valve 23, close the bypass electric regulating valve 10 and the solenoid valve 14, and adjust the flow rate of the variable frequency test pump 9 so that the flow rate of the variable frequency test pump 9 is equal to the difference between A and D.

[0091] Oil flows from the pressurization branch into the input end of the fixed frequency test pump 5, and into the input end of the variable frequency test pump 9. Oil flows from the output end of the fixed frequency test pump 5 through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank 1, while the other part flows back to the input end of the fixed frequency test pump 5.

[0092] Oil flows from the output of the variable frequency test pump 9 through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank 1, while part of the oil flows back to the input of the variable frequency test pump 9.

[0093] When setting the preset test flow rate, there will be no situation where the preset test flow rate is set to be greater than the sum of B and D.

[0094] S5. Based on the preset test temperature value, the temperature of the closed test unit is controlled by observing the temperature sensor inside the closed test unit and through the temperature control branch.

[0095] Read the data from temperature sensor 11. When the data from temperature sensor 11 is less than the preset test temperature value, increase the flow rate of the electric temperature regulating valve 25 to quickly return the cold oil to the oil tank 1, heat the oil in the oil tank 1, and then send it back to the closed test unit through the pressurization branch. When the data from temperature sensor 11 is greater than the preset test temperature value, increase the flow rate of the electric temperature regulating valve 25 to quickly return the hot oil to the oil tank 1, cool the oil in the oil tank 1, and then send the cold oil to the closed test unit through the pressurization branch. When the data from temperature sensor 11 is equal to the preset test temperature value, decrease the flow rate of the electric temperature regulating valve 25 to keep the oil in the pipeline of the closed test unit warm.

[0096] S6. Read the data from the first product differential pressure sensor or the second product differential pressure sensor in the closed test unit, read the data from the product inlet pressure sensor in the closed test unit, read the data from the first pipeline flow meter or the second pipeline flow meter in the closed test unit, and read the data from the temperature sensor.

[0097] When solenoid valve 14 is opened and electric regulating valve 23 is closed, data from the second pipeline flow meter 13 is read. When electric switching valve 23 is opened and solenoid valve 14 is closed, data from the first pipeline flow meter 22 is read. When the data from the first pipeline flow meter 22, the second pipeline flow meter 13, and the temperature sensor 11 are stable, data from the first pipeline flow meter 22 or the second pipeline flow meter 13 is read according to the opening and closing status of solenoid valve 14 and electric switching valve 23. Data from temperature sensor 11 is also read. Data from product inlet pressure sensor 21 in the main channel is read. Data from first product differential pressure sensor 19 is also read. When the data from first product differential pressure sensor 19 reaches its maximum range, data from second product differential pressure sensor 20 is read. Here, "stable" means that the data from the first pipeline flow meter 22 or the second pipeline flow meter 13 differs from the preset test flow rate value by ±2, and the data from temperature sensor 11 differs from the preset test temperature value by ±2.

[0098] During the flow resistance test of this solution, the product test flow resistance is typically between 0.15 and 0.4 bar, with extremely small pressure differentials. The closed-loop test unit pump set can be a low-pressure, high-flow pump set with extremely low power consumption. The product test pressure is provided by the static pressure of the auxiliary unit, which can be a high-pressure, low-flow pump set with extremely low power consumption. Higher product test pressures and larger test flow rates are required. Compared to open systems, less liquid is needed, resulting in lower operating costs and better energy savings.

[0099] The test oil required for a closed-loop test unit depends on the system volume, not the test flow rate. This significantly reduces the amount of test oil needed, thereby greatly reducing the heating and cooling power of auxiliary systems. Higher product requirements necessitate higher test pressures and flow rates. Compared to open-loop systems, manufacturing costs are lower.

[0100] The following points need to be explained:

[0101] (1) The accompanying drawings of the embodiments of the present invention only involve the structures involved in the embodiments of the present invention. Other structures can refer to the general design.

[0102] (2) For clarity, the thickness of layers or regions is enlarged or reduced in the drawings used to describe embodiments of the invention, i.e., these drawings are not drawn to scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being “above” or “below” another element, the element may be “directly” located “above” or “below” the other element or there may be intermediate elements.

[0103] (3) Where there is no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0104] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A closed system for high-pressure, high-current-resistance testing, characterized in that, The system includes a temperature-controlled liquid storage unit, a closed-loop test unit, an auxiliary unit, and a recovery unit. The closed-loop test unit is used to measure the pressure difference across the test specimen, the input pressure of the test specimen, the flow rate of the test specimen, and the operating temperature of the test specimen. The recovery unit is used to recover the oil in the test specimen after the test. The temperature-controlled liquid storage unit delivers heated oil to the closed-loop test unit through the auxiliary unit. The closed-loop test unit discharges oil to the temperature-controlled liquid storage unit through the auxiliary unit. The auxiliary unit is used to pressurize the closed-loop test unit and control its temperature.

2. The closed-loop system for high-pressure, high-flow-resistance testing according to claim 1, characterized in that, The closed test unit includes a first branch and a second branch connected in parallel, as well as a third branch and a fourth branch connected in parallel. The first branch is connected in series with the third branch and the fourth branch, respectively. The second branch is connected in series with the third branch. The first branch includes a main path and a first branch and a second branch connected in parallel. The main path is connected in series with the first branch and the second branch, respectively.

3. The closed-loop system for high-pressure, high-flow-resistance testing according to claim 2, characterized in that, The main passage is connected in sequence from the input end to the output end of the main passage to an upstream manual switch valve, a product inlet pressure sensor, a test piece, and a downstream manual switch valve. A sampling valve is also provided on the main passage. The first product differential pressure sensor is connected to the input and output terminals of the test piece, and the second product differential pressure sensor is connected to the input and output terminals of the test piece. Each input and output terminal of the test piece is connected to an exhaust solenoid valve. The output terminal of the first branch is connected to the input terminal of the main circuit, and the output terminal of the second branch is connected to the input terminal of the main circuit. The first branch is equipped with a first pipeline flow meter and an electric switching valve in sequence from the input end to the output end, and the second branch is equipped with a second pipeline flow meter, a back pressure regulating valve and a solenoid valve in sequence from the input end to the output end.

4. The closed system for high-pressure, high-flow-resistance testing according to claim 3, characterized in that, The second branch is equipped with a bypass electric regulating valve. The third branch is equipped with a frequency conversion test pump and a first filter in sequence from the input end to the output end. The first filter is connected to an oil drain valve. The fourth branch is equipped with a high-pressure pump inlet pressure sensor, a fixed-frequency test pump and a check valve in sequence from the input end to the output end. The main passage is equipped with a temperature sensor.

5. The closed-loop system for high-pressure, high-flow-resistance testing according to claim 2, characterized in that, The auxiliary unit includes a temperature control branch, a pressurization branch, and a regulating branch. The input end of the pressurization branch is connected to the output end of the oil tank in the temperature-controlled liquid storage unit via an input pipeline. The pressurization branch is equipped with an oil drain valve and two variable frequency high-pressure pumps sequentially from the input end to the output end. The output end of the pressurization branch is connected to the input ends of the third and fourth branches, respectively. The temperature control branch is equipped with an electric temperature regulating valve. The input end of the temperature control branch is connected to the output end of the main circuit. The output end of the temperature control branch is connected to the input end of the oil tank via an output pipeline. The regulating branch is equipped with a bypass valve. The input end of the regulating branch is connected to the output end of the pressurization branch. The output end of the regulating branch is connected to the input end of the oil tank via an output pipeline.

6. The closed-loop system for high-pressure, high-flow-resistance testing according to claim 2, characterized in that, The recovery unit includes an oil collection tray, the output end of which is connected to the input end of a manual T-type three-way ball valve, the output end of which is connected to the input end of an oil guide pump, the output end of which is connected to the input end of a second filter, and the output end of the second filter is connected to the input end of an oil tank in the temperature-controlled liquid storage unit.

7. The closed-loop system for high-pressure, high-flow-resistance testing according to claim 6, characterized in that, The output end of the main passage is connected to the other input end of the manual T-type three-way ball valve via a maintenance pipeline.

8. A method for using a closed-loop system for high-pressure, high-flow-resistance testing, characterized in that, The closed-loop testing system for filter testing as described in any one of claims 2 to 7, the method comprising: S1. Preset test flow rate, test pressure, and test temperature values; S2. Open the oil tank in the temperature-controlled liquid storage unit and fill all pipelines in the closed test unit with oil through the pressurization branch of the auxiliary unit, and vent the air through the exhaust solenoid valve. S3. Pressurize the closed test unit through the pressurization branch according to the preset test pressure value; S4. Select the working pipeline according to the preset test flow rate value; S5. Based on the preset test temperature value, the temperature of the closed test unit is controlled by observing the temperature sensor inside the closed test unit and through the temperature control branch. S6. Read the data from the first product differential pressure sensor or the second product differential pressure sensor in the closed test unit, read the data from the product inlet pressure sensor in the closed test unit, read the data from the first pipeline flow meter or the second pipeline flow meter in the closed test unit, and read the data from the temperature sensor.

9. The method of using the closed system for high-pressure, high-flow-resistance testing according to claim 8, characterized in that, In step S2, opening the oil tank in the temperature-controlled liquid storage unit to fill all pipelines in the closed test unit with oil through the pressurization branch of the auxiliary unit, and venting the oil through the exhaust solenoid valve includes: Open the oil drain valve and two variable frequency high-pressure pumps on the pressurization branch in the auxiliary unit, open the variable frequency test pump on the third branch, open the bypass electric regulating valve on the second branch, open the solenoid valve on the second branch, open the upstream manual switch valve and the downstream manual switch valve on the main passage, and open the temperature electric regulating valve on the temperature control branch in the auxiliary unit. Oil flows from the oil tank in the temperature-controlled storage unit into the pressurized branch and then into the input end of the variable frequency test pump. From the output end of the variable frequency test pump, the oil flows sequentially through the first filter on the third branch, the second pipeline flow meter on the second branch, the back pressure regulating valve and solenoid valve on the second branch, the upstream manual switch valve, the test piece, and the downstream manual switch valve. Part of the oil then passes through the temperature electric regulating valve and flows back to the oil tank through the output pipeline. The other part of the oil flows back to the input end of the variable frequency test pump. From the output end of the variable frequency test pump, the oil flows through the bypass electric regulating valve and then back to the input end of the variable frequency test pump. At this time, the oil fills the third branch, the second branch, the second branch, and the main passage. Then open the fixed-frequency test pump on the fourth branch, the check valve on the fourth branch, and the electric switch valve on the first branch, and close the solenoid valve; Part of the oil in the pressurization branch flows into the fixed frequency test pump, and then flows sequentially through the check valve, the first pipeline flow meter on the first branch, the electric switch valve, the upstream manual switch valve, the test piece and the downstream manual switch valve. Part of the oil then passes through the temperature electric regulating valve and flows back to the oil tank through the output pipeline. The other part of the oil flows back to the input end of the fixed frequency test pump. Another portion of the oil in the pressurized branch flows into the input end of the variable frequency test pump. The oil flows from the output end of the variable frequency test pump sequentially through the first filter, the first pipeline flow meter, the electric switch valve, the upstream manual switch valve, the test piece, and the downstream manual switch valve. A portion of the oil then passes through the temperature electric regulating valve and flows back to the oil tank through the output pipeline, while the other portion flows back to the input end of the variable frequency test pump. The oil flows from the output end of the variable frequency test pump through the bypass electric regulating valve and then back to the input end of the variable frequency test pump. At this time, the first branch, the second branch, the third branch, and the fourth branch are filled with oil. Adjust the two exhaust solenoid valves to exhaust air. When there are no more air bubbles in all pipelines within the closed test unit, the exhaust stops. The step of applying pressure to the closed test unit through the pressurization branch according to the preset test pressure value in S3 includes: Adjust the two variable frequency high-pressure pumps according to the preset test pressure value so that the data of the high-pressure pump inlet pressure sensor on the fourth branch is equal to the preset test pressure value.

10. The method of using the closed system for high-pressure, high-flow-resistance testing according to claim 9, characterized in that, The selection of the working pipeline based on the preset test flow rate value in S4 includes: When the preset test flow rate is less than or equal to the maximum flow rate of the variable frequency test pump but greater than or equal to the minimum flow rate of the variable frequency test pump, the fixed frequency test pump, bypass electric regulating valve and electric switching valve are closed, the variable frequency test pump is opened, and the flow rate of the variable frequency test pump is adjusted according to the preset test flow rate. The solenoid valve is opened, and the oil flows from the pressurization branch into the input end of the variable frequency test pump, and then flows from the output end of the variable frequency test pump through the second branch and the main passage in sequence. A part of the oil flows into the temperature control branch and then flows back to the oil tank, and the other part of the oil flows back to the input end of the variable frequency test pump. When the preset test flow rate is less than the minimum flow rate of the variable frequency test pump, close the fixed frequency test pump and the electric switch valve, and open the bypass electric regulating valve, the variable frequency test pump and the solenoid valve so that the bypass electric regulating valve can pass the sum of the flow rate and the preset test flow rate equals the minimum flow rate of the variable frequency test pump. Oil flows from the pressurization branch into the input end of the variable frequency test pump. From the output end of the variable frequency test pump, the oil flows sequentially through the second branch and the main passage. Part of the oil flows into the temperature control branch and then back to the oil tank, while the other part flows back to the input end of the variable frequency test pump. Additionally, oil flows from the output end of the variable frequency test pump through the bypass electric regulating valve and then back to the input end of the variable frequency test pump. When the preset test flow rate value is greater than the maximum flow rate of the variable frequency test pump At this time, the preset test flow rate is A, the maximum flow rate of the variable frequency test pump is B, the minimum flow rate of the variable frequency test pump is C, the flow rate of the fixed frequency test pump is D, and the flow rate of the bypass electric regulating valve is E. When A=D, open the fixed frequency test pump and the electric switch valve, and close the variable frequency test pump, the bypass electric regulating valve and the solenoid valve. Oil flows from the pressurization branch into the input end of the fixed frequency test pump. Oil flows from the output end of the fixed frequency test pump through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank. The other part of the oil flows back to the input end of the fixed frequency test pump. When A is less than the sum of C and D, open the fixed frequency test pump, variable frequency test pump, electric switch valve and bypass electric regulating valve, and close the solenoid valve to make A = C + DE; Oil flows from the pressurization branch into the input end of the fixed frequency test pump in part and into the input end of the variable frequency test pump in part. Oil flows from the output end of the fixed frequency test pump through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank. The other part of the oil flows back to the input end of the fixed frequency test pump. Oil flows sequentially from the output of the variable frequency test pump through the first branch and the main passage. Part of the oil flows into the temperature control branch and then back to the oil tank, while the other part flows back to the input of the variable frequency test pump. Oil also flows from the output of the variable frequency test pump through the second branch and then back to the input of the variable frequency test pump. When A is greater than or equal to the sum of C and D and less than or equal to the sum of B and D, open the fixed frequency test pump, variable frequency test pump and electric switch valve, close the bypass electric regulating valve and solenoid valve, and adjust the flow rate of the variable frequency test pump so that the flow rate of the variable frequency test pump is equal to the difference between A and D. Oil flows from the pressurization branch into the input end of the fixed frequency test pump in part and into the input end of the variable frequency test pump in part. Oil flows from the output end of the fixed frequency test pump through the first branch and the main passage in sequence. Part of the oil flows into the temperature control branch and then back to the oil tank. The other part of the oil flows back to the input end of the fixed frequency test pump. Oil flows sequentially from the output of the variable frequency test pump through the first branch and the main passage. Part of the oil flows into the temperature control branch and then back to the oil tank, while the other part flows back to the input of the variable frequency test pump. The step S5, which involves controlling the temperature of the closed test unit by observing the temperature sensor within the closed test unit and controlling the temperature through the temperature control branch based on a preset test temperature value, includes: The system reads temperature sensor data. When the temperature sensor data is lower than the preset test temperature value, it increases the flow rate of the electric temperature regulating valve to quickly return cold oil to the oil tank, heat the oil in the tank, and then send it back to the closed test unit through the pressurization branch. When the temperature sensor data is higher than the preset test temperature value, it increases the flow rate of the electric temperature regulating valve to quickly return hot oil to the oil tank, cool the oil in the tank, and then send the cold oil to the closed test unit through the pressurization branch. When the temperature sensor data is equal to the preset test temperature value, it decreases the flow rate of the electric temperature regulating valve to keep the oil in the pipeline of the closed test unit warm. The steps in S6, namely reading data from the first or second product differential pressure sensor within the closed-loop test unit, reading data from the product inlet pressure sensor within the closed-loop test unit, reading data from the first or second pipeline flow meter within the closed-loop test unit, and reading data from the temperature sensor, include: When the solenoid valve is opened and the electric regulating valve is closed, the data of the second pipeline flow meter is read. When the electric switching valve is opened and the solenoid valve is closed, the data of the first pipeline flow meter is read. When the data of the first pipeline flow meter or the second pipeline flow meter and the temperature sensor are stable, the data of the first pipeline flow meter or the second pipeline flow meter are read according to the opening and closing status of the solenoid valve and the electric switching valve, the temperature sensor data is read, the data of the product inlet pressure sensor on the main channel is read, and the data of the first product differential pressure sensor is read. When the data of the first product differential pressure sensor reaches the maximum value of the range, the data of the second product differential pressure sensor is read.

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