A unidirectional sine flow signal generating and calibrating device

Abstract

The present invention discloses a unidirectional sine flow signal generating and calibrating device for calibrating a flowmeter to be measured, which includes a measuring medium, an oil tank for storing the measuring medium, a variable pump, a sine flow signal generator, a flowmeter to be measured, a differential cylinder, an average flow valve, a standard flowmeter, a position feedback valve, and a processor. The oil tank is communicated with the P port of the sine flow signal generator through the variable pump. The average flow valve and the position feedback valve cooperate to form a position feedback for the differential cylinder. A speed sensor, a standard flowmeter, and the flowmeter to be measured are respectively connected to the processor. The present invention solves the technical problem in the prior art that the measurement and calibration method for generating a unidirectional variable flow velocity flow signal is restricted by the limited piston stroke of the hydraulic cylinder and does not have the ability of continuous calibration.

Description

Technical Field

[0001] The present invention relates to the technical field of flow measurement, and in particular to a device for generating and calibrating a unidirectional sinusoidal flow signal. Background Art

[0002] A positive displacement flowmeter, also known as a fixed displacement flowmeter, is one of the most accurate types in flow meters. It uses a mechanical measuring element to continuously divide the fluid into individual known volume parts, and measures the total volume of the fluid according to the number of times the measuring chamber is successively filled and discharged with this volume part of the fluid.

[0003] Positive displacement flowmeters are widely used in the field of flow measurement. To obtain the dynamic measurement accuracy of the flowmeter, a calibration device is required to calibrate the dynamic flow measurement performance of the flowmeter by generating a dynamic flow signal and calibrating this signal. Currently, most of the dynamic flow signals generated by the calibration device for calibrating the dynamic flow measurement performance of the flowmeter are standard sinusoidal flow signals, that is, the flow signals passing through the flowmeter to be measured are bidirectional. There are few measurement and calibration methods for generating unidirectional variable flow velocity flow signals, and due to the limited stroke of the hydraulic cylinder piston, there is no ability for continuous calibration.

[0004] The inventors of the present application found that the above prior art has at least the following technical problems:

[0005] In the prior art, the measurement and calibration method for generating a unidirectional variable flow velocity flow signal is restricted by the limited stroke of the hydraulic cylinder piston and cannot be continuously calibrated. Summary of the Invention

[0006] By providing a device for generating and calibrating a unidirectional sinusoidal flow signal in an embodiment of the present application, the technical problem in the prior art that the measurement and calibration method for generating a unidirectional variable flow velocity flow signal is restricted by the limited stroke of the hydraulic cylinder piston and does not have the ability for continuous calibration is solved. In the embodiment of the present application, the processor sends a unidirectional sinusoidal signal to the sinusoidal flow signal generator, the fixed differential pressure reducing valve controls the pressure difference, the servo valve is controlled to output a flow signal Q1 = Asin2πft, and the plate throttle valve is controlled to output Q2 = B. Thus, the sinusoidal flow signal generator outputs a flow signal of Q 总 = Asin2πft + B, achieving the beneficial effect of being able to continuously generate unidirectional sinusoidal flow signals with different pressures, different amplitudes, and different offset amounts, and the hydraulic cylinder piston for calibration can reciprocate near the middle position, that is, the phenomenon of cylinder jamming will not occur, and it can accurately and continuously calibrate the measurement performance of the flowmeter for unidirectional sinusoidal flow signals with different frequencies and different offset amounts under different pressures.

[0007] To solve the above problems, an embodiment of the present application provides a unidirectional sine flow signal generating and calibrating device, including a measurement medium, an oil tank for storing the measurement medium, a variable pump, a sine flow signal generator, a flowmeter to be measured, a differential cylinder, an average flow valve, a standard flowmeter, a position feedback valve, and a processor, where:

[0008] The differential cylinder has a piston rod that can be pushed by the measurement medium. The piston rod is placed in the differential cylinder barrel to form a rodless cavity and a rod chamber. The first end of the piston rod is connected to a piston, and the second end of the piston rod extends out of the differential cylinder barrel and can move axially;

[0009] The oil tank is connected to the P port of the sine flow signal generator through the variable pump. The A port of the sine flow signal generator is connected to the first opening of the flowmeter to be measured. The second opening of the flowmeter to be measured is connected to the rodless cavity of the differential cylinder. The rod chamber of the differential cylinder is connected to the P port of the sine flow signal generator. The P port of the average flow valve is connected to the rodless cavity of the differential cylinder. The T port of the average flow valve is connected to the first opening of the standard flowmeter. The second opening of the standard flowmeter is connected to the oil tank. The second end of the piston rod is connected to the position feedback valve through a connecting rod. The T port of the position feedback valve is connected to the oil tank;

[0010] The B port of the average flow valve is connected to the A port of the position feedback valve. The A port of the average flow valve is connected to the P port of the position feedback valve. The average flow valve and the position feedback valve cooperate to form position feedback for the differential cylinder;

[0011] A speed sensor for measuring the moving speed of the piston rod is connected to the second end of the piston rod. The signal output end of the speed sensor is connected to the processor to transmit the speed signal of the piston of the differential cylinder to the processor. The signal output end of the standard flowmeter is connected to the processor to transmit the flow signal passing through the average flow valve to the processor. The signal output end of the flowmeter to be measured is connected to the processor to transmit the flow signal measured by the flowmeter to be measured to the processor.

[0012] Further, the connecting rod is rotatably mounted on a support. The first end of the connecting rod is connected to the second end of the piston rod, and the second end of the connecting rod is connected to the feedback rod of the position feedback valve.

[0013] Further, the upper end of the support has a convex portion, and the connecting rod has a groove adapted to the convex portion.

[0014] Further, a first pressure gauge and a second pressure gauge are respectively installed at the first opening and the second opening of the flowmeter to be measured, and a third pressure gauge is installed at the B port of the average flow valve.

[0015] Further, the sine flow signal generator includes a servo valve, a plate throttle valve and a constant differential pressure reducing valve. The servo valve and the plate throttle valve are connected in parallel through a sixth oil pipe and a seventh oil pipe, and the plate throttle valve and the constant differential pressure reducing valve are connected in parallel through an eighth oil pipe and a ninth oil pipe. The processor is respectively connected to the servo valve and the plate throttle valve to send control signals to the servo valve and the plate throttle valve, so as to adjust the amplitude and bias of the flow signal of the flowmeter.

[0016] Further, both ends of the average flow valve are in a differential form, that is, the working area of the A port is smaller than that of the B port.

[0017] Further, a pressure regulating member for regulating the pressure of the measuring medium is further provided between the variable pump and the fuel tank.

[0018] Further, the pressure regulating member is a first overflow valve. The inlet of the first overflow valve is connected to the outlet of the variable pump through a second oil pipe, and the outlet of the first overflow valve is connected to the fuel tank through a first oil pipe, so as to regulate the pressure of the measuring medium passing through the flowmeter to be measured by changing the threshold value of the first overflow valve.

[0019] Further, the position feedback valve can be a rotary valve or a slide valve.

[0020] Further, the B port of the average flow valve is connected to the second accumulator through a twentieth oil pipe.

[0021] Further, the device further includes a direct-acting pressure reducing valve for voltage stabilization. The T port of the direct-acting pressure reducing valve is connected to the fuel tank, the A port of the direct-acting pressure reducing valve is connected to the A port of the average flow valve, and the P port of the direct-acting pressure reducing valve is connected to the P port of the sine flow signal generator.

[0022] Further, the piston rod is horizontally arranged from the first end to the second end.

[0023] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0024] 1. In the one-way sine flow signal generating and calibrating device described in the embodiment of the present application, the processor sends a one-way sine signal to the sine flow signal generator, the constant differential pressure reducing valve controls the pressure difference, the servo valve is controlled to output a flow signal Q1 = Asin2πft, and the plate throttle valve is controlled to output Q2 = B, so that the sine flow signal generator outputs Q总 a flow signal of \(A\sin(2\pi ft)+B\), thus solving the technical problem in the prior art that the measurement and calibration method for generating a unidirectional variable flow velocity flow signal is restricted by the limited piston stroke of the hydraulic cylinder and does not have the ability of continuous calibration, achieving the beneficial effect of being able to continuously generate unidirectional sine flow signals with different pressures, different amplitudes, and different offset amounts, and the piston of the hydraulic cylinder for calibration can reciprocate near the middle position, that is, the phenomenon of cylinder jamming will not occur, and the measurement performance of the flowmeter for unidirectional sine flow signals with different frequencies and different offset amounts under different pressures can be accurately and continuously calibrated.

[0025] 2. By changing the thresholds of the first overflow valve and the second overflow valve, the unidirectional sine flow signal generating and calibrating device described in the embodiment of the present application can change the pressure of the system, thereby providing different test pressures for the flowmeter to be measured, enabling the device to generate dynamic flow signals with different pressures, solving the technical problem of inability to continuously calibrate, and achieving the beneficial effect of being able to continuously generate unidirectional sine flow signals with different pressures, different amplitudes, and different offset amounts.

[0026] 3. In the unidirectional sine flow signal generating and calibrating device described in the embodiment of the present application, the position feedback valve and the average flow valve are combined to form a position feedback effect on the differential cylinder, thereby ensuring that the differential cylinder reciprocates near the middle position, enabling the unidirectional sine flow signal generated by the sine flow signal generator to be well split into the P port of the average flow valve and the rodless cavity of the differential cylinder, that is, the unidirectional sine flow signal \(Q1\) flows into the rodless cavity of the differential cylinder, and the offset flow signal \(Q2\) flows into the P port of the average flow valve, solving the technical problem in the prior art that the unidirectional high-frequency flow signal simulated by the device for high-pressure dynamic measurement of the flowmeter is discontinuous, and achieving the beneficial effect of being able to generate continuous calibration of the unidirectional high-frequency flow signal.

[0027] 4. The processor described in the embodiment of the present application can receive the speed signal from the speed sensor and calculate the unidirectional sine flow signal \(Q1\) entering the rodless cavity of the differential cylinder; the processor can receive the offset flow signal \(Q2\) flowing through the average flow valve measured by the standard flowmeter, and the total flow obtained by adding the two can be used to compare with the data read by the flowmeter to be measured, so as to calibrate the measurement accuracy of the flowmeter to be measured for the dynamic flow signal, providing a new solution for the calibration of the measurement performance of the dynamic flowmeter.

[0028] In summary, after the thresholds of the first overflow valve and the second overflow valve of the device described in the embodiments of the present application are set, the position feedback valve and the average flow valve cooperate to form a position feedback effect on the differential cylinder, ensuring that the differential cylinder reciprocates in its middle position, so that the unidirectional sinusoidal flow signal generated by the sinusoidal flow signal generator is well shunted to the P port of the average flow valve and the rodless cavity of the differential cylinder; the processor receives the speed signal from the speed sensor and calculates the unidirectional sinusoidal flow signal Q1 entering the rodless cavity of the differential cylinder. The processor receives the offset flow signal Q2 flowing through the average flow valve measured by the standard flowmeter. The total flow obtained by adding the two is compared with the data read by the flowmeter to be measured, and the measurement accuracy of the dynamic flow signal of the flowmeter to be measured is calibrated by comparison. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of a unidirectional sinusoidal flow signal generating and calibrating device provided in the embodiments of the present application;

[0030] Figure 2 It is the flow rate Q generated by the device provided in the embodiments of the present application 总 = 3.15sin2πt + 21.5 flow fluctuation diagram;

[0031] Figure 3a It is the device provided in the embodiments of the present application that receives Figure 2 Under the provided flow signal, the flow signal diagram obtained by the speed sensor;

[0032] Figure 3b It is the device provided in the embodiments of the present application that receives Figure 2 Under the provided flow signal, the flow signal diagram obtained by the standard flowmeter;

[0033] Figure 4 It is the flow rate Q generated by the device provided in the embodiments of the present application 总 = 3.15sin40πt + 21.5 flow fluctuation diagram;

[0034] Figure 5a It is the device provided in the embodiments of the present application that receives Figure 4 Under the provided flow signal, the flow signal diagram obtained by the speed sensor;

[0035] Figure 5b It is the device provided in the embodiments of the present application that receives Figure 4 Under the provided flow signal, the flow signal diagram obtained by the standard flowmeter.

[0036] Description of the reference numerals: fuel tank 1, first overflow valve 2, variable pump 3, check valve 4, first accumulator 5, sine flow signal generator 6, flowmeter to be measured 7, first pressure gauge 8, second pressure gauge 9, differential cylinder 10, speed sensor 11, connecting rod 12, position feedback valve 13, direct-acting pressure reducing valve 14, average flow valve 15, standard flowmeter 16, second overflow valve 17, processor 18, second accumulator 19, third pressure gauge 20, first oil pipe 21, second oil pipe 22, third oil pipe 23, fourth oil pipe 24, fifth oil pipe 25, sixth oil pipe 26, seventh oil pipe 27, eighth oil pipe 28, ninth oil pipe 29, tenth oil pipe 30, eleventh oil pipe 31, twelfth oil pipe 32, thirteenth oil pipe 33, fourteenth oil pipe 34, fifteenth oil pipe 35, sixteenth oil pipe 36, seventeenth oil pipe 37, eighteenth oil pipe 38, nineteenth oil pipe 39, twentieth oil pipe 40, twenty-first oil pipe 41, twenty-second oil pipe 42, twenty-third oil pipe 43. Detailed implementation manners

[0037] In an embodiment of the present application, by providing a unidirectional sine flow signal generating and calibrating device, the technical problem in the prior art that the measurement and calibration method for generating a unidirectional variable flow rate flow signal is restricted by the limited piston stroke of the hydraulic cylinder and does not have the ability of continuous calibration is solved. The overall idea of the technical solution in the embodiment of the present application to solve the above crosstalk technical problem is as follows: a unidirectional sine signal is sent to the sine flow signal generator by the processor, the fixed differential pressure reducing valve controls the pressure difference, the servo valve is controlled to output a flow signal Q1 = Asin2πft, and the plate throttle valve is controlled to output Q2 = B, so that the sine flow signal generator outputs a flow signal of Q 总 = Asin2πft + B, realizing the continuous generation of unidirectional sine flow signals with different pressures, different amplitudes, and different offset amounts, and the piston of the hydraulic cylinder for calibration can reciprocate near the middle position, that is, the phenomenon of cylinder jamming will not occur, and the measurement performance of the flowmeter for unidirectional sine flow signals with different frequencies and different offset amounts under different pressures can be accurately and continuously calibrated.

[0038] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings of the specification and specific implementation manners.

[0039] Figure 1 The structural schematic diagram of a unidirectional sine flow signal generating and calibrating device provided in this embodiment is as Figure 1As shown, the device is used for calibrating the flowmeter 7 to be measured, and includes a measuring medium, an oil tank 1 for storing the measuring medium, a variable pump 3, a sine flow signal generator 6, a flowmeter 7 to be measured, a differential cylinder 10, an average flow valve 15, a standard flowmeter 16 (the standard flowmeter meets national standards for each parameter and does not require in-situ flow detection), a position feedback valve 13, and a processor 18, where:

[0040] The differential cylinder 10 has a piston rod that can be pushed by the measuring medium. The piston rod is placed in the differential cylinder barrel to form a rodless chamber and a rod chamber. The first end of the piston rod is connected to a piston, and the second end of the piston rod extends out of the differential cylinder barrel and can move axially;

[0041] The oil tank 1 is connected to the inlet of the variable pump 3 through a third oil pipe 23. The outlet of the variable pump 3 is sequentially connected to the P port of the sine flow signal generator 6 through a fourth oil pipe 24, a one-way valve 4, a first accumulator 5, and a fifth oil pipe 25. The A port of the sine flow signal generator 6 is connected to the first opening of the flowmeter 7 to be measured through a tenth oil pipe 30. The second opening of the flowmeter 7 to be measured is connected to the rodless chamber of the differential cylinder 10 through an eleventh oil pipe 31. The rod chamber of the differential cylinder 10 is connected to the P port of the sine flow signal generator 6 through a thirteenth oil pipe 33. The P port of the average flow valve 15 is connected to the rodless chamber of the differential cylinder 10 through a twelfth oil pipe 32. The T port of the average flow valve 15 is connected to the first opening of the standard flowmeter 16 through a twenty-first oil pipe 41. The second opening of the standard flowmeter 16 is connected to the inlet of a second overflow valve 17 through a twenty-second oil pipe 42. The outlet of the second overflow valve 17 is connected to the oil tank 1 through a twenty-third oil pipe 43. The second end of the piston rod is connected to the position feedback valve 13 through a connecting rod 12. The T port of the position feedback valve 13 is connected to the oil tank 1 through a nineteenth oil pipe 39;

[0042] A pressure regulating member for regulating the pressure of the measuring medium is further provided between the variable pump 3 and the oil tank 1. In this embodiment, the pressure regulating member is a first overflow valve 2. The inlet of the first overflow valve 2 is connected to the outlet of the variable pump 3 through a second oil pipe 22, and the outlet of the first overflow valve 2 is connected to the oil tank 1 through a first oil pipe 21 to regulate the pressure of the measuring medium passing through the flowmeter 7 to be measured by changing the threshold value of the first overflow valve 2.

[0043] The B port of the average flow valve 15 is connected to the A port of the position feedback valve 13 through an eighteenth oil pipe 38. The A port of the average flow valve 15 is connected to the P port of the position feedback valve 13 through a seventeenth oil pipe 37. The average flow valve 15 and the position feedback valve 13 cooperate to form position feedback for the differential cylinder 10;

[0044] Specifically, when the measuring medium flows into the rodless chamber of the differential cylinder 10, it pushes the piston rod to move to the right. After being driven by the connecting rod, the P port of the position feedback valve 13 is connected to the A port, and the high-pressure measuring medium in the control oil circuit enters the B port of the average flow valve 15. Since the valve core of the average flow valve 15 is of a differential type, it pushes the valve core of the average flow valve 15 to displace, so that the P port of the average flow valve 15 is connected to the T port and the flow area increases. That is, the measuring medium enters the P port of the average flow valve 15 through the twelfth oil pipe 32, thereby reducing the flow rate entering the differential cylinder 10. When the opening of the average flow valve 15 is large, most of the flow enters the P port of the average flow valve 15, the pressure in the rodless chamber of the differential cylinder 10 is low, and the piston of the differential cylinder 10 moves to the left. After being driven by the connecting rod 12, the A port of the position feedback valve 13 is connected to the T port, so that the pressure at the B port of the average flow valve 15 decreases, the valve core of the average flow valve 15 displaces, and the flow area between the P port and the T port of the average flow valve 15 decreases to close, so that the flow rate through the average flow valve 15 decreases and the flow rate entering the differential cylinder 10 increases. The position feedback valve 13 and the average flow valve 15 are combined to form a position feedback function for the differential cylinder 10, ensuring that the differential cylinder 10 reciprocates in its middle position, so that the unidirectional sine flow signal generated by the sine flow signal generator 6 is well shunted to the P port of the average flow valve 15 and the rodless chamber of the differential cylinder 10.

[0045] A speed sensor 11 for measuring the moving speed of the piston rod is connected to the second end of the piston rod. The signal output end of the speed sensor 11 is connected to the processor 18 to transmit the speed signal of the piston of the differential cylinder 10 to the processor 18. The signal output end of the standard flowmeter 16 is connected to the processor 18 to transmit the flow signal passing through the average flow valve 15 to the processor 18. The signal output end of the flowmeter 7 to be measured is connected to the processor 18 to transmit the flow signal measured by the flowmeter 7 to be measured to the processor 18.

[0046] Specifically, the processor 18 receives the speed signal from the speed sensor 11 and calculates the flow signal Q1 entering the rodless chamber of the differential cylinder 10. The processor 18 receives the flow signal Q2 flowing through the average flow valve 15 measured by the standard flowmeter 16. The total flow obtained by adding Q1 and Q2 can be used to compare with the data read by the flowmeter 7 to be measured to calibrate the measurement accuracy of the flowmeter 7 to be measured for the dynamic flow signal.

[0047] Further, the connecting rod 12 is rotatably mounted on a support 44. The first end of the connecting rod 12 is connected to the second end of the piston rod, and the second end of the connecting rod 12 is connected to the feedback rod of the position feedback valve 13. The upper end of the support 44 has a convex portion, and the connecting rod 12 has a groove adapted to the convex portion.

[0048] Further, a first pressure gauge 8 and a second pressure gauge 9 are respectively installed at the first opening and the second opening of the flowmeter 7 to be measured, and a third pressure gauge 20 is installed at the B port of the average flow valve 15.

[0049] Specifically, by changing the thresholds of the first overflow valve 2 and the second overflow valve 17, the pressure of the flow rate (the measurement medium in the device) can be changed to provide flow rate values of different pressures for the device.

[0050] Further, the sine flow signal generator 6 includes a servo valve 6.1, a plate throttle valve 6.2, and a constant differential pressure reducing valve 6.3. The servo valve 6.1 and the plate throttle valve 6.2 are connected in parallel through a sixth oil pipe 26 and a seventh oil pipe 27, and the plate throttle valve 6.2 and the constant differential pressure reducing valve 6.3 are connected in parallel through an eighth oil pipe 28 and a ninth oil pipe 29. The processor 18 is respectively connected to the servo valve 6.1 and the plate throttle valve 6.2 to send control signals to the servo valve 6.1 and the plate throttle valve 6.2, thereby adjusting the amplitude and offset amount of the flowmeter flow signal.

[0051] Specifically, a single - direction sine signal is sent to the sine flow signal generator 6 by the processor 18. The constant differential pressure reducing valve 6.3 controls the pressure difference. The servo valve 6.1 is controlled to output a flow signal Q1 = Asin2πft, and the plate throttle valve 6.2 is controlled to output Q2 = B. Thus, the sine flow signal generator 6 outputs a flow signal of 总 Q = Asin2πft + B, realizing the continuous generation of single - direction sine flow signals with different pressures, different amplitudes, and different offset amounts. And the hydraulic cylinder piston for calibration can reciprocate near the middle position, that is, the phenomenon of cylinder jamming will not occur, and it can accurately and continuously calibrate the measurement performance of the flowmeter for single - direction sine flow signals with different frequencies and different offset amounts under different pressures.

[0052] Further, both ends of the average flow valve 15 are in a differential form, that is, the working area of the A port is smaller than that of the B port.

[0053] Further, the position feedback valve 13 can be a rotary valve or a slide valve.

[0054] Further, the B port of the average flow valve 15 is connected to the second accumulator 19 through a twentieth oil pipe 40.

[0055] Further, the device further includes a direct-acting pressure reducing valve 14 for voltage stabilization. The T port of the direct-acting pressure reducing valve 14 is communicated with the fuel tank 1 through a fifteenth oil pipe 35. The A port of the direct-acting pressure reducing valve 14 is communicated with the A port of the average flow valve 15 through a sixteenth oil pipe 36. The P port of the direct-acting pressure reducing valve 14 is communicated with the P port of the sine flow signal generator 6 through a fourteenth oil pipe 34.

[0056] Further, the piston rod is horizontally arranged from the first end to the second end.

[0057] The flow path of the measurement medium of the unidirectional sine flow signal generating and calibrating device described in the embodiment of the present application is as follows:

[0058] The main oil path is divided into three paths after passing through the variable pump 3. One path enters the direct-acting pressure reducing valve 14 to form a control oil path. One path enters the rodless cavity of the differential cylinder 10. One path enters the P port of the sine flow signal generator 6.

[0059] When the sine flow generator 6 is in the closed state, the variable pump 3 is started, and the measurement medium in the fuel tank 1 sequentially passes through the variable pump 3 and the second overflow valve 17 and returns to the fuel tank 1.

[0060] When the sine flow generator 6 is in the working state, the variable pump 3 is started. The measurement medium in the fuel tank 1 sequentially passes through the variable pump 3, the sine flow signal generator 6, and the flowmeter to be measured 7. Then, a part of the measurement medium enters the rodless cavity of the differential cylinder 10, and another part enters the average flow valve 15, and then passes through the standard flowmeter 16 and the second overflow valve 17 and returns to the fuel tank 1.

[0061] In the control oil path, a part of the measurement medium enters the A port of the average flow valve 15, and a part of the measurement medium enters the P port of the position feedback valve 13. The A port of the position feedback valve 13 is communicated with the B port of the average flow valve 15.

[0062] The working principle of the unidirectional sine flow signal generating and calibrating device described in the embodiment of the present application is as follows:

[0063] When performing a flowmeter dynamic performance test using the generating and calibrating device described in the embodiment of the present application, first, the processor 18 sends a unidirectional sine signal to the sine flow signal generator 6. The fixed-differential pressure reducing valve 6.3 controls the pressure difference. The servo valve 6.1 is controlled to output a flow signal Q1 = Asin2πft, and the plate throttle valve 6.2 is controlled to output Q2 = B. Thus, the sine flow signal generator 6 outputs Q 总The flow signal of = Asin2πft + B realizes the continuous generation of a unidirectional sinusoidal flow signal with different pressures, different amplitudes, and different offset amounts. Moreover, the hydraulic cylinder piston used for calibration can reciprocate near the middle position, that is, the phenomenon of hitting the cylinder will not occur, and it can accurately and continuously calibrate the measurement performance of the flowmeter for unidirectional sinusoidal flow signals with different frequencies and different offset amounts under different pressures.

[0064] As Figure 1 shown, when the measurement medium flows into the rodless chamber of the differential cylinder, it pushes the piston rod of the differential cylinder to move to the right. After being driven by the connecting rod, the P port of the position feedback valve is connected to the A port, and the high-pressure measurement medium in the control oil circuit enters the B port of the average flow valve. Since the spool of the average flow valve is of a differential type, it thus pushes the spool of the average flow valve to displace, causing the P port of the average flow valve to be connected to the T port and the flow area to increase. That is, the measurement medium enters the P port of the average flow valve through the twelfth oil pipe, thereby reducing the flow rate entering the differential cylinder. When the opening of the average flow valve is large, most of the flow enters the P port of the average flow valve, the pressure in the rodless chamber of the differential cylinder is low, and the piston of the differential cylinder moves to the left. After being driven by the connecting rod, the A port of the position feedback valve is connected to the T port, causing the pressure at the B port of the average flow valve to decrease, causing the spool of the average flow valve to displace, reducing the flow area between the P port and the T port of the average flow valve to close, reducing the flow rate through the average flow valve, and increasing the flow rate entering the differential cylinder. The position feedback valve and the average flow valve are combined to form a position feedback effect on the differential cylinder, ensuring that the differential cylinder reciprocates near its middle position, so that the unidirectional sinusoidal flow signal generated by the sinusoidal flow signal generator is well split into the P port of the average flow valve and the rodless chamber of the differential cylinder, that is, the unidirectional sinusoidal flow signal Q1 and the flow entering the rodless chamber of the differential cylinder, and the offset flow signal Q2 enters the P port of the average flow valve. The processor can receive the speed signal from the speed sensor and calculate the flow signal Q1 entering the rodless chamber of the differential cylinder; the processor can receive the flow signal Q2 flowing through the average flow valve measured by the standard flowmeter, so that the total flow obtained by adding can be used to compare with the data read by the flowmeter to be measured, and calibrate the measurement accuracy of the flowmeter to be measured for dynamic flow signals.

[0065] Specifically, the unidirectional sinusoidal flow signal generation and calibration device described in the embodiments of the present application can continuously generate unidirectional sinusoidal flow signals with different pressures and different amplitudes, and at the same time can accurately and continuously calibrate the measurement performance of the flowmeter to be measured for dynamic flow signals under the above working conditions.

[0066] Figure 2 For the flow rate Q generated by the device provided in the embodiments of the present application总 Flow fluctuation diagram of Q = 3.15sin2πt + 21.5; Figure 3a The flow signal diagram obtained by the speed sensor under the flow signal provided to the device in the embodiment of the present application; Figure 2 The flow signal diagram obtained by the standard flowmeter under the flow signal provided to the device in the embodiment of the present application. Referring to Figure 3b The flow signal diagram obtained by the speed sensor under the flow signal provided to the device in the embodiment of the present application; Figure 2 The flow signal diagram obtained by the standard flowmeter under the flow signal provided to the device in the embodiment of the present application. Referring to Figure 2 Figures 3a and 3b, it can be seen that the device described in the embodiment of the present application can ensure the continuous generation of a unidirectional sinusoidal flow signal, and at the same time can accurately and continuously calibrate the measurement performance of the flowmeter to be measured for the dynamic flow signal under the above working conditions.

[0067] Figure 4 The flow Q generated by the device provided in the embodiment of the present application is 总 Flow fluctuation diagram of Q = 3.15sin40πt + 21.5; Figure 5a The flow signal diagram obtained by the speed sensor under the flow signal provided to the device in the embodiment of the present application; Figure 4 The flow signal diagram obtained by the standard flowmeter under the flow signal provided to the device in the embodiment of the present application. Referring to Figure 5b The flow signal diagram obtained by the speed sensor under the flow signal provided to the device in the embodiment of the present application; Figure 4 The flow signal diagram obtained by the standard flowmeter under the flow signal provided to the device in the embodiment of the present application. Referring to Figure 2 Figures 5a and 5b, it can be seen that the device described in the embodiment of the present application can ensure the continuous generation of a unidirectional sinusoidal flow signal, and at the same time can accurately and continuously calibrate the measurement performance of the flowmeter to be measured for the dynamic flow signal under the above working conditions.

[0068] In summary, when the thresholds of the first overflow valve and the second overflow valve of the device described in the embodiment of the present application are adjusted, the position feedback valve and the average flow valve cooperate to form a position feedback effect on the differential cylinder, ensuring the reciprocating movement of the differential cylinder in its middle position, so that the unidirectional sinusoidal flow signal generated by the sinusoidal flow signal generator is well shunted to the P port of the average flow valve and the rodless cavity of the differential cylinder; the processor receives the speed signal from the speed sensor and calculates the unidirectional sinusoidal flow signal Q1 entering the rodless cavity of the differential cylinder, the processor receives the offset flow signal Q2 flowing through the average flow valve measured by the standard flowmeter, and the sum of the two is compared with the data read by the flowmeter to be measured, and the measurement accuracy of the dynamic flow signal of the flowmeter to be measured is calibrated by comparison.

[0069] It should be understood that the outer, middle, inner and other orientation terms mentioned or possibly mentioned in this specification are defined relative to the structures shown in the respective drawings, and they are relative concepts, so they may change accordingly according to their different positions and different usage states. Therefore, these or other orientation terms should not be construed as restrictive terms.

[0070] As described above, it is only the preferred embodiment of the present application, and does not impose any formal or substantial restrictions on the present application. It should be noted that for those of ordinary skill in the art of this technology, without departing from the method of the present application, several improvements and supplements can still be made, and these improvements and supplements should also be regarded as the protection scope of the present invention. Those skilled in the art, without departing from the spirit and scope of the present application, when making some equivalent changes such as minor modifications, decorations and evolutions using the technical content disclosed above, are all equivalent embodiments of the present application; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A unidirectional sine flow signal generating and calibrating device, characterized in that, It includes a measuring medium, an oil tank for storing the measuring medium, a variable pump, a sine flow signal generator, a flowmeter to be measured, a differential cylinder, an average flow valve, a standard flowmeter, a position feedback valve, and a processor, where: The differential cylinder has a piston rod that can be pushed by the measuring medium. The piston rod is placed in the differential cylinder barrel to form a rodless chamber and a rod chamber. The first end of the piston rod is connected to a piston, and the second end of the piston rod extends out of the differential cylinder barrel and can move axially; The oil tank is communicated with the P port of the sine flow signal generator through the variable pump. The A port of the sine flow signal generator is communicated with the first opening of the flowmeter to be measured. The second opening of the flowmeter to be measured is communicated with the rodless chamber of the differential cylinder. The rod chamber of the differential cylinder is communicated with the P port of the sine flow signal generator. The P port of the average flow valve is communicated with the rodless chamber of the differential cylinder. The T port of the average flow valve is communicated with the first opening of the standard flowmeter. The second opening of the standard flowmeter is communicated with the oil tank. The second end of the piston rod is connected to the position feedback valve through a connecting rod. The T port of the position feedback valve is communicated with the oil tank; The B port of the average flow valve is communicated with the A port of the position feedback valve, and the A port of the average flow valve is communicated with the P port of the position feedback valve. The average flow valve and the position feedback valve cooperate to form position feedback for the differential cylinder; A speed sensor for measuring the moving speed of the piston rod is connected to the second end of the piston rod. The signal output end of the speed sensor is connected to the processor to transmit the speed signal of the piston of the differential cylinder to the processor. The signal output end of the standard flowmeter is connected to the processor to transmit the flow signal passing through the average flow valve to the processor. The signal output end of the flowmeter to be measured is connected to the processor to transmit the flow signal measured by the flowmeter to be measured to the processor.

2. The one-way sine flow signal generating and calibrating device according to claim 1, characterized in that, The connecting rod is rotatably mounted on a support. The first end of the connecting rod is connected to the second end of the piston rod, and the second end of the connecting rod is connected to the feedback rod of the position feedback valve.

3. The one-way sine flow signal generating and calibrating device according to claim 2, wherein, The upper end of the support has a convex portion, and the connecting rod has a groove adapted to the convex portion.

4. A unidirectional sine flow signal generating and calibrating device according to claim 1, characterized in that, A first pressure gauge and a second pressure gauge are respectively installed at the first opening and the second opening of the flowmeter to be measured, and a third pressure gauge is installed at the B port of the average flow valve.

5. A unidirectional sine flow signal generating and calibrating device according to claim 1, characterized in that, The sine flow signal generator includes a servo valve, a plate throttle valve, and a constant differential pressure reducing valve. The servo valve and the plate throttle valve are connected in parallel through a sixth oil pipe and a seventh oil pipe. The plate throttle valve and the constant differential pressure reducing valve are connected in parallel through an eighth oil pipe and a ninth oil pipe. The processor is respectively connected to the servo valve and the plate throttle valve to transmit control signals to the servo valve and the plate throttle valve, thereby adjusting the amplitude and offset amount of the flowmeter flow signal.

6. The one-way sine flow signal generating and calibrating device according to claim 1 or 4, characterized in that, Both ends of the average flow valve are in a differential form, that is, the working area of the A port is smaller than the working area of the B port.

7. A unidirectional sine flow signal generating and calibrating device according to claim 1, characterized in that, A pressure regulating member for adjusting the pressure of the measuring medium is further provided between the variable pump and the oil tank.

8. The unidirectional sine flow signal generating and calibrating device according to claim 7, characterized in that, The pressure regulating member is a first overflow valve. The inlet of the first overflow valve is connected to the outlet of the variable pump through a second oil pipe, and the outlet of the first overflow valve is connected to the fuel tank through a first oil pipe, so as to adjust the pressure of the measuring medium passing through the flowmeter to be measured by changing the threshold value of the first overflow valve.

9. The unidirectional sine flow signal generating and calibrating device according to claim 3, characterized in that, The position feedback valve described above can be a rotary valve or a slide valve.

10. A unidirectional sine flow signal generating and calibrating device according to claim 1, characterized in that, The device further includes a direct-acting pressure reducing valve for stabilizing pressure. The T port of the direct-acting pressure reducing valve is communicated with the fuel tank, the A port of the direct-acting pressure reducing valve is communicated with the A port of the average flow valve, and the P port of the direct-acting pressure reducing valve is communicated with the P port of the sine flow signal generator.

Images