Micro-flow standard device
By designing a micro flow standard device, the calibration master cylinder and sensor combined with volume and mass measurement method, combined with temperature and pressure data, the problem of insufficient calibration accuracy of micro flow pump displacement in the prior art is solved, and higher measurement accuracy is achieved and automated operations.
Patent Information
- Application Number
- CN202421129169.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-22
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-05-22
AI Technical Summary
The displacement calibration accuracy of existing micro-flow pumps is limited by the measurement range and accuracy of the flowmeter, so accurate measurement cannot be achieved.
A small flow standard device is designed, including calibration master cylinder, cylinder liner, cylinder rod, grating ruler, temperature sensor, pressure sensor, auxiliary reset cylinder and guide rod, to measure the volume or mass of the liquid through the displacement of the cylinder rod, combining temperature and Pressure data, real-time calibration of the displacement of the micro-flow pump, use the counterweight to reduce friction resistance, and photoelectric switches to detect strokes to ensure accurate measurement.
It improves the standard displacement measurement accuracy of micro-flow pumps, reduces the risk of liquid leakage, achieves higher measurement accuracy and automated empties, and reduces manual operation.
Smart Images
Figure CN222231822U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of liquid flow verification, in particular to a micro-flow standard device. Background Art
[0002] With the development of technology, micro-flow syringe pumps and peristaltic pumps are widely used in the medical and chemical industries. In the medical industry, micro-syringe pumps can be used as infusion pumps, drug pumps, and washing pumps, and are widely used in treatment processes such as hemodialysis and extracorporeal circulation. In the chemical industry, micro-flow peristaltic pumps can be used for liquid separation and mixing. Therefore, precise control of micro-flow can not only ensure the treatment effect, but also reduce risks and costs. At present, the displacement calibration of such micro-flow pumps mostly relies on flow meters, and their calibration accuracy is limited by the measurement range and measurement accuracy of the flow meter, and cannot be accurately measured.
[0003] The Chinese invention patent application with application publication number CN115931088A discloses a small liquid flow standard device combining piston and weighing method, including a dual-principle liquid flow standard device in which the piston volume method provides a volume standard value and the weighing method provides a mass standard value. The standard device should include a piston, a grating ruler, a power and transmission system, an upper water supply tank, a liquid pipeline, a high-precision analytical balance and an upper computer control system. The power and transmission system should include a stepper motor and its driver and a ball screw. The upper computer control system should include a computer. The liquid pipeline should be installed with a temperature and pressure sensor at an appropriate position to collect the temperature and pressure of the working fluid in the pipeline in real time. The above-mentioned disclosed scheme provides a volume standard value and a weighing method by the piston volume method, and the small liquid displacement can be obtained by the final calculation, but the above-mentioned disclosed scheme does not disclose a method for improving the measurement accuracy of the small liquid displacement, and the measurement accuracy of the above-mentioned disclosed scheme can be further improved during the measurement process. Utility Model Content
[0004] Technical purpose: In order to overcome the deficiencies in the prior art, the utility model provides a small flow standard device.
[0005] Technical solution: To achieve the above-mentioned purpose, the utility model discloses a micro-flow standard device, including a calibration master cylinder, the calibration master cylinder including a cylinder sleeve and a cylinder rod that moves linearly along the inner tube of the cylinder sleeve, a liquid inlet and a liquid outlet are respectively provided at both ends of the cylinder sleeve, and a counterweight block is provided at the end of the cylinder rod to offset the friction force between the cylinder sleeve and the cylinder rod.
[0006] Preferably, the cylinder liner is also provided with a temperature sensor for measuring the temperature of the liquid, a pressure sensor for measuring the pressure of the liquid, and an exhaust port for exhausting.
[0007] Preferably, a grating ruler is also provided at the end of the cylinder rod, and a reading head of the grating ruler achieves synchronous displacement with the cylinder rod.
[0008] Preferably, a sealing ring is provided between the cylinder sleeve and the cylinder rod, and the sealing ring is a Y-shaped sealing ring.
[0009] Preferably, it also includes an auxiliary reset cylinder and a guide rod, the guide rods are arranged on both sides of the calibration main cylinder, the guide sleeves sleeved on the outside of the guide rods are connected to the cylinder rods, and the end of the telescopic rod of the auxiliary reset cylinder is connected to a push plate, which is sleeved on two groups of guide rods and can be moved up and down along the guide rods.
[0010] Preferably, two groups of photoelectric switches are provided within the stroke range of the cylinder rod, respectively used to detect the minimum stroke and maximum stroke of the cylinder rod, and the fixing plate of the photoelectric switch is provided with long holes for adjusting the positions of the two groups of photoelectric switches.
[0011] Preferably, the first pipeline support and the second pipeline support are respectively provided on the liquid inlet and liquid outlet sides of the calibration master cylinder, and the first pipeline support and the second pipeline support are respectively provided with a first pipeline cover plate and a second pipeline cover plate for fixing the pipeline outside, and the first pipeline support and the second pipeline support are both provided with pipeline grooves for pipeline arrangement.
[0012] Preferably, a cylinder for controlling the on-off of the pipeline is provided outside the pipeline groove, the cylinder is provided with a connecting block at the rod head position, the pipeline groove is provided with an on-off groove at the corresponding position of the connecting block, and the on-off groove cooperates with the connecting block.
[0013] Preferably, it also includes a protective outer cover, wherein rollers are provided at the four corners of the bottom of the protective outer cover, and a touch screen for display control is provided on the upper part of the protective outer cover.
[0014] The beneficial effects of the utility model are:
[0015] 1. The micro-flow pump to be calibrated supplies liquid to the liquid inlet of the calibration master cylinder to displace the cylinder rod. The standard displacement of the micro-flow pump is obtained according to the displacement distance of the cylinder rod or the discharge volume of the liquid outlet based on the volume measurement method or the mass measurement method. In order to improve the measurement accuracy of the standard displacement, the counterweight block at the end of the cylinder rod can offset the friction during the movement of the cylinder rod to prevent the micro-flow pump to be calibrated from leaking liquid due to resistance during the process of pumping liquid to the calibration master cylinder, affecting the displacement accuracy of the micro-flow pump to be calibrated, thereby achieving accurate measurement of the standard displacement of the micro-flow.
[0016] 2. To further improve the measurement accuracy, the cylinder sleeve of the calibration master cylinder is equipped with a temperature sensor and a pressure sensor, which can detect the temperature and pressure of the liquid inside the cylinder sleeve in real time, and accurately calculate the displacement according to the change trend of the liquid density with temperature and pressure, so as to improve the displacement accuracy. The setting of the exhaust interface can be used to measure the exhaust of the gas inside the front cylinder sleeve to prevent the compressibility of the gas in the cylinder sleeve from causing errors in the measurement accuracy of the liquid displacement.
[0017] 3. The reading head of the grating ruler follows the movement of the cylinder rod and can accurately measure the moving distance of the cylinder rod. The guide rod plays a guiding role during the movement of the cylinder rod to prevent deflection, thereby improving the measurement accuracy of the grating ruler. The auxiliary reset cylinder is used to calibrate the automatic emptying of the liquid in the main cylinder and reduce the workload of manual emptying. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the overall structure of the utility model;
[0019] Figure 2 This is a schematic diagram of the internal structure of the utility model;
[0020] Figure 3 This is a schematic diagram of the structure of the calibration master cylinder of the utility model;
[0021] Figure 4 This is a cross-sectional view of the calibration master cylinder of the utility model;
[0022] Figure 5 For this utility model Figure 4 A partial enlarged view of the middle A area;
[0023] Figure 6 It is a schematic diagram of the second pipeline support in the figure of the utility model;
[0024] Figure 7 It is a schematic diagram of the first pipeline support in the figure of the utility model.
[0025] In the figure, 1, touch screen; 2, protective cover; 3, roller; 4, calibration main cylinder; 401, liquid inlet; 402, cylinder sleeve; 403, temperature sensor; 404, pressure sensor; 405, exhaust interface; 406, liquid outlet; 407, cylinder rod; 5, test liquid inlet; 6, pre-liquid inlet; 7, counterweight; 8, grating ruler; 801, reading head; 9, auxiliary reset cylinder; 10, guide rod; 11, guide sleeve; 12, push plate; 13, photoelectric switch; 14, fixing plate; 15, length Strip hole; 16, second pipeline support; 17, second pipeline cover; 18, cylinder; 19, first pipeline support; 20, first pipeline cover; 21, pipeline groove; 22, on-off groove; 23, exhaust hose inlet end; 24, liquid hose inlet end; 25, liquid hose outlet end; 26, exhaust hose outlet end; 27, exhaust hose collection end; 28, test liquid connecting hose port; 29, pre-liquid connecting hose port; 30, liquid hose collection end; 31, connecting block; 32, sealing ring. DETAILED DESCRIPTION
[0026] The following is combined with Figure 1 To Attachment Figure 7 The principles and features of the present invention are described, and the examples given are only used to explain the present invention, and are not used to limit the scope of the present invention.
[0027] A small flow standard device, such as Figure 1 — Figure 7 As shown, it includes a protective cover 2, and rollers 3 are provided at the four corners of the bottom of the protective cover 2 to realize flexible movement of the device. A touch screen 1 for display control is provided on the upper part of the protective cover 2, and the touch screen 1 can display the pressure value, temperature value and action control of the actuator during the calibration process. A calibration master cylinder 4 is provided inside the protective cover 2, and the calibration master cylinder 4 is placed vertically. The calibration master cylinder 4 includes a cylinder sleeve 402 and a cylinder rod 407 that moves linearly along the inner tube of the cylinder sleeve 402. The two ends of the cylinder sleeve 402 are respectively provided with a liquid inlet 401, a liquid outlet 406 and an exhaust interface 405. The liquid inlet 401 is provided with a test liquid inlet 5 and a pre-liquid inlet 6. Before the formal standard test, the pre-liquid inlet 6 injects liquid into the cylinder sleeve 402 through the pre-liquid inlet 6, so that the gas inside it is discharged through the exhaust interface 405 to prevent the gas in the cylinder sleeve 402 from affecting the displacement calibration accuracy.
[0028] In order to realize the centralized arrangement of pipelines, the first pipeline support 19 and the second pipeline support 16 are respectively fixed near the liquid inlet 401 and the liquid outlet 406 of the calibration master cylinder 4, and are provided with pipeline grooves 21, and a connecting hose is arranged in the pipeline groove 21. The liquid outlet 406 and the exhaust interface 405 of the calibration master cylinder 4 are respectively connected with the liquid outlet hose inlet end 24 and the exhaust hose inlet end 23 in the second pipeline support 16, and are discharged through the liquid outlet hose outlet end 25 and the exhaust hose outlet end 26, and enter the liquid outlet hose collection end 30 and the exhaust hose collection end 27 of the first pipeline support 19 respectively, and the test liquid inlet 5 and the pre-liquid inlet 6 are respectively connected with the test liquid connecting hose port 28 and the pre-liquid connecting hose port 29 of the first pipeline support 19, so that the pipelines are centrally led out from the outlet end of the first pipeline support 19 to the outside of the protective cover 2. In order to facilitate the on-off control of the pipeline, a cylinder 18 for controlling the on-off of the pipeline is provided outside the pipeline groove 21, and a connecting block 31 is provided at the rod head position of the cylinder 18. The pipeline groove 21 is provided with an on-off groove 22 at the corresponding position of the connecting block 31. The on-off groove 22 cooperates with the connecting block 31. Through the control of the air circuit solenoid valve, when the connecting block 31 is pushed into the on-off groove 22, the pipeline is cut off, and when the connecting block 31 is separated from the on-off groove 22, the pipeline is connected. The first pipeline support 19 and the second pipeline support 16 are respectively provided with a first pipeline cover plate 20 and a second pipeline cover plate 17 for fixing the pipeline to prevent the pipeline from falling off.
[0029] During the formal standard test, the micro-flow pump to be calibrated injects liquid into the cylinder sleeve 402 through the test liquid inlet 5, and the liquid pushes the cylinder rod 407 to move. The end of the cylinder rod 407 is provided with a grating ruler 8. The reading head 801 of the grating ruler 8 and the cylinder rod 407 achieve synchronous displacement, and the displacement distance L of the cylinder rod 407 per unit time can be determined. According to the inner diameter r of the cylinder sleeve 402, the volume measurement method is: V = πr 2 ×L, the standard displacement per unit time of the micro-flow pump to be calibrated is measured. The discharged liquid from the liquid outlet 406 per unit time can also be led out to a standard container for weighing to obtain the weight m of the discharged liquid. The standard displacement per unit time of the micro-flow pump to be calibrated is measured by the mass measurement method: V = M ÷ ρ, where ρ is the liquid density. According to the characteristics of liquid density changing with temperature and pressure, in order to ensure the measurement accuracy of the displacement, the cylinder sleeve 402 is also provided with a temperature sensor 403 for measuring the temperature of the liquid, and a pressure sensor 404 for measuring the pressure of the liquid. Compared with the temperature sensor 403 and the pressure sensor 404 installed on the pipeline, directly installing them on the cylinder sleeve 402 can avoid heat exchange and pressure drop of the liquid in the pipeline, and the accuracy is higher.
[0030] In order to ensure the measurement accuracy of the grating ruler 8, two sets of guide rods 10 are also provided on both sides of the calibration main cylinder 4. The guide sleeve 11 sleeved on the outside of the guide rod 10 is connected to the cylinder rod 407, so that the cylinder rod 407 always moves along the guide rod 10 during the displacement process without deflection. In order to facilitate the automatic emptying of the liquid inside the cylinder sleeve 402 after the flow standard test, an auxiliary reset cylinder 9 is also provided on one side of the calibration main cylinder 4. The cylinder body of the auxiliary reset cylinder 9 is fixed, and the end of its telescopic rod is connected to a push plate 12. The push plate 12 is sleeved on the two sets of guide rods 10 and can move up and down along the guide rod 10. The liquid in the cylinder sleeve 402 can be emptied during the upward displacement of the guide rod 10. In this embodiment, the auxiliary reset cylinder 9 is a cylinder, and its movement is controlled by an air circuit solenoid valve. The control principle of the cylinder movement is a technical knowledge well known to those skilled in the art, and will not be repeated here. Of course, the auxiliary reset cylinder 9 here can also use an oil cylinder or an electric cylinder, both of which can realize the displacement movement of the push plate 12.
[0031] In order to prevent liquid leakage, a sealing ring 32 is provided between the cylinder sleeve 402 and the cylinder rod 407. In order to reduce the friction resistance during the movement of the cylinder rod 407, the sealing ring 32 is preferably a Y-shaped sealing ring. In order to prevent the small flow pump from leaking liquid due to the existence of friction resistance during the process of pumping liquid to the calibration master cylinder 4, thereby affecting the displacement measurement accuracy, a counterweight block 7 is provided at the end of the cylinder rod 407 to counteract the friction resistance.
[0032] In order to prevent the cylinder rod 407 from exceeding the range during movement, two groups of photoelectric switches 13 are provided within the stroke range of the cylinder rod 407, which are respectively used to detect the minimum stroke and the maximum stroke of the cylinder rod 407. The fixing plate 14 of the photoelectric switch 13 is provided with a long hole 15 for adjusting the position of the two groups of photoelectric switches 13. When the cylinder rod 407 reaches the minimum stroke or the maximum stroke, the photoelectric switch 13 triggers a signal, the displacement of the cylinder rod 407 stops, and at the same time, the supply of liquid to the calibration master cylinder 4 stops or the discharge of liquid stops.
[0033] During the displacement standard operation, first ensure that the pipeline connected to the exhaust interface 405 and the pre-liquid inlet 6 of the calibration main cylinder 4 is in a connected state, the cylinder rod 407 is in the minimum stroke position of the photoelectric switch 13, the external liquid supply pump supplies liquid to the cylinder sleeve 402 through the pre-liquid inlet 6, and the gas in the cylinder sleeve 402 is discharged through the exhaust interface 405. After the emptying is completed, the pipeline connected to the exhaust interface 405 and the pre-liquid inlet 6 is cut off. Open the test liquid inlet 5 connecting pipeline, the micro-flow pump to be calibrated supplies liquid to the cylinder sleeve 402, and the cylinder rod 407 moves until the cylinder rod 407 is in the maximum stroke position of the photoelectric switch 13, record the time T and the displacement distance L of the cylinder rod 407, and obtain the standard displacement of the micro-flow pump to be calibrated according to the volume measurement method. Alternatively, the liquid in the cylinder sleeve 402 is discharged to the standard container through the liquid outlet 406 through the auxiliary reset cylinder 9 for weighing and measurement, and the standard displacement of the micro-flow pump to be calibrated is obtained according to the mass measurement method. The micro-displacement measured by this device has higher accuracy.
[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A micro flow standard device, characterized in that: The invention comprises a calibration master cylinder (4), wherein the calibration master cylinder (4) comprises a cylinder sleeve (402) and a cylinder rod (407) which moves linearly along the inner tube of the cylinder sleeve (402), wherein two ends of the cylinder sleeve (402) are respectively provided with a liquid inlet (401) and a liquid outlet (406), and a counterweight (7) which counteracts the friction force between the cylinder sleeve (402) and the cylinder rod (407) is provided at the end of the cylinder rod (407).
2. The micro flow standard device according to claim 1, characterized in that: The cylinder sleeve (402) is also provided with a temperature sensor (403) for measuring the temperature of the liquid, a pressure sensor (404) for measuring the pressure of the liquid, and an exhaust port (405) for exhausting.
3. The micro flow standard device according to claim 1, characterized in that: A grating ruler (8) is also provided at the end of the cylinder rod (407), and a reading head (801) of the grating ruler (8) achieves synchronous displacement with the cylinder rod (407).
4. The micro flow standard device according to claim 1, characterized in that: A sealing ring (32) is provided between the cylinder sleeve (402) and the cylinder rod (407), and the sealing ring (32) is a Y-shaped sealing ring.
5. The micro flow standard device according to claim 1, characterized in that: It also includes an auxiliary reset cylinder (9) and a guide rod (10), wherein the guide rods (10) are arranged on both sides of the calibration main cylinder (4), a guide sleeve (11) sleeved on the outside of the guide rod (10) is connected to the cylinder rod (407), and a push plate (12) is connected to the end of the telescopic rod of the auxiliary reset cylinder (9), and the push plate (12) is sleeved on two groups of the guide rods (10) and can move up and down along the guide rods (10).
6. The micro flow standard device according to claim 5, characterized in that: Two groups of photoelectric switches (13) are provided within the stroke range of the cylinder rod (407), respectively used to detect the minimum stroke and maximum stroke of the cylinder rod (407); a fixing plate (14) of the photoelectric switch (13) is provided with a long hole (15) for adjusting the positions of the two groups of photoelectric switches (13).
7. The micro flow standard device according to claim 1, characterized in that: A first pipeline support (19) and a second pipeline support (16) are respectively provided on the liquid inlet (401) and the liquid outlet (406) sides of the calibration master cylinder (4); a first pipeline cover plate (20) and a second pipeline cover plate (17) for fixing pipelines are respectively provided outside the first pipeline support (19) and the second pipeline support (16); and pipeline grooves (21) for arranging pipelines are provided on the first pipeline support (19) and the second pipeline support (16).
8. The micro flow standard device according to claim 7, characterized in that: A cylinder (18) for controlling the on-off of the pipeline is arranged outside the pipeline groove (21); a connecting block (31) is arranged at the rod head position of the cylinder (18); an on-off groove (22) is arranged at a position corresponding to the connecting block (31) of the pipeline groove (21); and the on-off groove (22) matches the connecting block (31).
9. The micro flow standard device according to claim 1, characterized in that: It also comprises a protective outer cover (2), wherein rollers (3) are provided at the four corners of the bottom of the protective outer cover (2), and a touch screen (1) for display control is provided at the upper part thereof.