Variable temperature flowmeter verification method

Abstract

A variable temperature flowmeter calibration method, the clamping pipe in the calibration method is arranged in an oil bath tank, the oil bath tank is set as an overflow tank, and oil forms an oil circulation between the oil bath tank and a variable temperature oil tank, which accelerates the heat exchange speed of the oil, makes the temperature of the oil in the instrument clamping pipe closer to the temperature of the oil in the oil bath tank, and makes the temperature difference of the whole circulation pipeline smaller, so that the measurement precision is high; the reversing device in the calibration method has a high reversing speed and small interference to the oil flow field, the oil entering the oil container of the weighing device has a small wall hanging amount, has a small influence on the measurement precision, the three piston cylinders of the weighing device and the reversing valve are used in cooperation, the oil entering the oil container weighing and the piston cylinder B extracting the oil can be synchronously performed, the weighing reading of the weighing instrument and the oil backflow to the variable temperature oil tank can be synchronously performed, the whole action process is compact, and the combination of the reversing device and the oil bath tank can realize automatic high-efficiency constant-temperature continuous weighing, and the detection efficiency and precision are high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of liquid flowmeter calibration, in particular to a variable-temperature flowmeter calibration method. BACKGROUND

[0002] Flowmeters are instruments for measuring the flow of fluid media, and are widely used in chemical industry, food industry, pharmaceutical industry and daily life. The precision of flowmeters needs to be measured and calibrated when they are shipped and during use, so as to ensure the precision of the flowmeters. Static weighing is a common way for flowmeter calibration. The weighing container in the static weighing flowmeter calibration device is placed on a weighing instrument. The weighing container is used to contain the liquid flowing from the reversing oil inlet mechanism. The weighing instrument weighs the weighing container after the liquid flows in. After the weighing is completed, the liquid in the weighing container needs to be discharged, and then the next weighing is performed. At present, the liquid in the weighing container is discharged by directly pouring or through a liquid discharge pipe. These two methods need manual operation repeatedly and cannot be perfectly matched with the reversing mechanism, so the degree of automation is low and the weighing error is large. In addition, the liquid circulates in the pipeline between the liquid tank and the instrument clamping device. The heat exchange speed is different at different positions during the liquid flow. There is a temperature difference between the pipeline sections, which causes different pressures and flow rates, affecting the accuracy of the calibration. Therefore, it is necessary to design a calibration method with high measurement accuracy and high automation degree. SUMMARY

[0003] In order to solve the above problems, the present application provides a variable-temperature flowmeter calibration method.

[0004] The technical scheme of the present application is as follows: a variable-temperature flowmeter calibration method, comprising the following steps:

[0005] S1, connecting a circulating pipeline A to the outlet of a variable-temperature oil tank, installing an oil pump on the circulating pipeline A, connecting a circulating pipeline B to the inlet of the variable-temperature oil tank, installing a stop valve A at the connection between the circulating pipeline B and the variable-temperature oil tank, connecting a constant temperature device between the outer ends of the circulating pipeline A and the circulating pipeline B, and installing an instrument in the constant temperature device;

[0006] S2, connecting a branch pipeline between the middle part of the circulating pipeline B and the variable-temperature oil tank, providing a stop valve B on the branch pipeline, and connecting a weighing device to the branch pipeline;

[0007] S3, connecting a reversing device to the branch pipeline at the front end of the weighing device, connecting a liquid discharge pipe A of the reversing device into the weighing device, and connecting a liquid discharge pipe B of the reversing device to the variable-temperature oil tank;

[0008] S4, start the oil pump and open the stop valve B, the oil in the variable temperature oil tank enters the constant temperature device from the circulation pipeline A, keeps the pipeline at the instrument connection in a constant temperature state, and then enters the reversing device from the branch pipeline;

[0009] S5, drive the reversing device to discharge the oil from the drain pipe A to the weighing device, and when the oil reaches the preset liquid level and stabilizes, read the data, at the same time, drive the reversing device to discharge the oil from the drain pipe B to the variable temperature oil tank, and keep the oil in the pipeline circulating;

[0010] S6, after the weighing device reads the data and empties the internal oil, drive the reversing device to discharge the oil from the liquid outlet pipe A to the weighing device for weighing, and repeat steps S5 and S6 to realize continuous measurement of the weighing device.

[0011] Preferably, the constant temperature device comprises an oil bath tank and an instrument clamping pipe installed in the oil bath tank, one end of the instrument clamping pipe is in communication with the circulation pipeline A and is provided with an adjusting valve A at the connection, the other end is in communication with the circulation pipeline B and is provided with an adjusting valve A at the connection, and the instrument is clamped in the middle of the instrument clamping pipe and immersed in the oil in the oil bath tank.

[0012] Preferably, a liquid inlet pipe is connected between the circulation pipeline A and one end of the oil bath tank, and an adjusting valve B is arranged on the liquid inlet pipe.

[0013] Preferably, the weighing device comprises a weighing machine and a piston oil pumping mechanism, the weighing machine is provided with an oil container, the piston oil pumping mechanism comprises a piston cylinder A, a piston cylinder B, a piston cylinder C and a reversing valve connected with a high-pressure gas source, the two ends of the piston cylinder A are respectively provided with a first inlet and outlet and a second inlet and outlet, the lower end of the piston cylinder B is provided with a third inlet and outlet, the two ends of the piston cylinder C are respectively provided with a fourth inlet and outlet and a fifth inlet and outlet, and the piston rod of the piston cylinder A extending downward and the piston rod of the piston cylinder B extending upward are coaxially fixedly connected.

[0014] A liquid return pipe is connected to the variable temperature oil tank, the outer end of the liquid return pipe is fixedly connected with the lower end of the piston rod of the piston cylinder C, the piston rod is located directly above the oil container, a suction pipe is connected between the middle of the liquid return pipe and the third inlet and outlet, one-way valve A and one-way valve B are arranged on the liquid return pipe on both sides of the suction pipe, a first high-pressure gas pipe is connected between the first inlet and outlet and the fourth inlet and outlet, a second high-pressure gas pipe is connected between the second inlet and outlet and the third inlet and outlet, and the reversing valve is connected between the first high-pressure gas pipe and the second high-pressure gas pipe through the high-pressure gas pipe.

[0015] Preferably, the asymmetric reversing mechanism comprises a bidirectional cylinder mounted in the middle of the support plate, an inverted V-shaped reversing pipe arranged at the lower end of the support plate, a sliding gap with the same length direction as the extension direction of the bidirectional cylinder arranged at one end of the bidirectional cylinder, a photoelectric probe fixedly connected to the bottom surface of the support plate, an outer end of the photoelectric probe being provided with a photosensitive groove corresponding to the sliding gap, photosensitive parts being correspondingly arranged on the two side walls of the photosensitive groove, a vertical pipe being arranged between the sliding gap and the photosensitive groove and extending into the upper part of the inverted V-shaped reversing pipe, a liquid discharge pipe A and a liquid discharge pipe B being connected to the lower part of the inverted V-shaped reversing pipe, an extension rod of the bidirectional cylinder being fixedly connected to an oil pipe joint, the oil pipe joint being connected to a branch pipeline.

[0016] Preferably, an adapter and a flexible pipe are arranged between the oil pipe joint and the branch pipeline, one interface of the adapter being connected to the branch pipeline, and the other interface being connected to the oil pipe joint through the flexible pipe.

[0017] Preferably, the method for continuously measuring the weighing device and the reversing device in S5 and S6 is as follows:

[0018] First step, oil feeding weighing: the bidirectional cylinder of the reversing device drives the vertical pipe to move outward and correspond to the liquid discharge pipe A below, oil liquid enters the oil liquid container of the weighing device from the liquid discharge pipe A, when the liquid level of the oil liquid reaches a predetermined position, the bidirectional cylinder drives the vertical pipe to move inward and correspond to the liquid discharge pipe B below, oil liquid enters the variable temperature oil liquid tank from the liquid discharge pipe B for continuous circulation, and after the oil liquid in the oil liquid container is stable, reading is performed.

[0019] Second step, oil emptying: after reading is completed, the reversing valve passes high-pressure gas from the second inlet and outlet to the piston cylinder A through the second high-pressure gas pipe and to the piston cylinder C through the fourth inlet and outlet, the piston rod in the piston cylinder C pushes the outer end of the reflux pipe into the oil liquid container, the piston rod in the piston cylinder A pulls the piston in the piston cylinder B upward, the piston cylinder B generates negative pressure in the reflux pipe through the suction pipe, the one-way valve B blocks the variable temperature oil liquid tank from being sucked into the reflux loop of the piston cylinder B, and oil liquid can only be sucked into the piston cylinder B through the one-way valve A;

[0020] Third step, oil feeding weighing again: after the oil liquid in the oil liquid tank is emptied, the bidirectional cylinder drives the vertical pipe to correspond to the liquid discharge pipe A below again, oil liquid reenters the oil liquid container, and at the same time, the reversing valve passes high-pressure gas from the first inlet and outlet to the piston cylinder A through the first high-pressure gas pipe and to the piston cylinder C through the fifth inlet and outlet, the piston rod of the piston cylinder C pulls the reflux pipe out of the oil liquid container, the piston rod of the piston cylinder A presses the piston of the piston cylinder B downward, and the oil liquid in the piston cylinder B is pressed out to the reflux pipe, the one-way valve A blocks the reflux loop of the oil liquid from the oil liquid container, and oil liquid can only return to the variable temperature oil liquid tank from the reflux pipe through the one-way valve B, after the oil liquid is stable and reading is completed, the second step is repeated to realize continuous reversing weighing.

[0021] Preferably, a filter is arranged on the circulation pipeline A between the oil pump and the variable-temperature oil tank, and a filter is arranged on the circulation pipeline A between the oil pump and the constant-temperature device.

[0022] Preferably, an overflow pipe is arranged between the middle part of the circulation pipeline A and the variable-temperature oil tank, and an overflow valve is arranged on the overflow pipe.

[0023] The beneficial technical effects of the present application are:

[0024] The clamped pipe in the detection method is arranged in the oil bath tank, the oil bath tank is an overflow tank, and oil liquid forms an oil liquid circulation between the oil bath tank and the variable-temperature oil tank, so that the heat exchange speed of the oil liquid is accelerated, the temperature of the oil liquid in the instrument clamped pipe is closer to the temperature of the oil liquid in the oil bath tank, the temperature difference of the whole circulation pipeline is smaller, the measurement precision is high, the temperature of the oil liquid in the whole circulation pipeline can be changed by changing the temperature in the constant-temperature oil tank, and the detection of the instrument under different oil liquid temperatures is adapted; the reversing device in the detection method has a high reversing speed and small interference to the oil liquid flow field, the wall-hanging amount of the oil liquid entering the oil liquid container of the weighing device is small, the influence on the measurement precision is small, the three piston cylinders of the weighing device are used in cooperation with the reversing valve, the oil liquid entering the oil liquid container weighing and the piston cylinder B extracting the oil liquid are synchronously performed, the weighing reading of the weighing instrument and the oil liquid backflow to the variable-temperature oil tank are synchronously performed, the whole action process is compact, and the automatic high-efficiency constant-temperature continuous weighing can be realized by combining the reversing device and the oil bath tank, and the detection efficiency and the detection precision are high. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a whole system schematic diagram of the present application;

[0026] Figure 2 is a system schematic diagram of the weighing device (the second inlet and outlet and the fourth inlet and outlet in the figure intake air, the direction of the solid line arrow is the direction of the high-pressure gas flow channel, and the direction of the dashed line arrow is the direction of the oil liquid flow channel);

[0027] Figure 3 is a system schematic diagram of the weighing device (the first inlet and outlet and the fifth inlet and outlet in the figure intake air, the direction of the solid line arrow is the direction of the high-pressure gas flow channel, and the direction of the dashed line arrow is the direction of the oil liquid flow channel);

[0028] Figure 4 is one of the three-dimensional structure schematic diagrams of the reversing device of the present application;

[0029] Figure 5 is another three-dimensional structure schematic diagram of the reversing device of the present application;

[0030] Figure 6 is a top view structure schematic diagram of the reversing device of the present application;

[0031] Figure 7 is Figure 6A-A sectional view of the figure;

[0032] Figure 8 A schematic diagram of the stereoscopic structure of the photoelectric probe of the present application.

[0033] In the figure, 01. Variable temperature oil tank, 11. Circulating pipeline A, 111. Oil pump, 12. Circulating pipeline B, 13. Branch pipeline, 131. Stop valve A, 132. Stop valve B, 14. Filter, 15. Overflow pipe, 151. Overflow valve, 16. Thermometer, 17. Pressure gauge, 18. Backup interface, 19. One-way valve C,

[0034] 02. Thermostat, 21. Oil bath, 22. Instrument clamping pipe, 221. Instrument, 23. Regulating valve A, 24. Liquid inlet pipe, 25. Regulating valve B, 26. Overflow port,

[0035] 03. Weighing device, 31. Scale, 311. Oil container, 32. Piston cylinder A, 321. First inlet and outlet, 322. Second inlet and outlet, 323. Piston rod of piston cylinder A extending downward, 33. Piston cylinder B, 331. Third inlet and outlet, 332. Piston rod of piston cylinder B extending upward, 34. Piston cylinder C, 341. Fourth inlet and outlet, 342. Fifth inlet and outlet, 343. Piston rod of piston cylinder C, 35. Liquid return pipe, 351. One-way valve A, 352. One-way valve B, 36. First high-pressure gas pipe, 37. Second high-pressure gas pipe, 38. Changeover valve, 381. High-pressure gas source, 39. Suction pipe,

[0036] 04. Changeover device, 41. Support plate, 411. Sliding notch, 42. Two-way air cylinder, 421. Telescopic rod, 43. Inverted V-shaped changeover pipe, 431. Drain pipe A, 432. Drain pipe B, 44. Photoelectric probe, 441. Light-sensitive groove, 442. Light-sensitive part, 45. Vertical pipe, 451. Quick-connect joint, 46. Adapter, 47. Flexible pipe, 48. Two-position three-way valve, 481. Air pipe A, 482. Air pipe B, 483. Regulating valve. DETAILED DESCRIPTION

[0037] Example one, see the description of figures 1-8, a variable temperature flowmeter calibration method, comprising the following steps:

[0038] S1, connect the outlet of the variable temperature oil tank to the circulating pipeline A, install an oil pump on the circulating pipeline A, connect the inlet of the variable temperature oil tank to the circulating pipeline B, install a stop valve A at the connection between the circulating pipeline B and the variable temperature oil tank, and the stop valve A is in the closed state during system calibration, connect the thermostat device between the outer ends of the circulating pipeline A and the circulating pipeline B, and install the instrument in the thermostat device;

[0039] S2, a branch pipeline is connected between the middle of the circulation pipeline B and the variable temperature oil tank, a stop valve B is arranged on the branch pipeline, and a weighing device is connected to the branch pipeline;

[0040] S3, a reversing device is connected to the branch pipeline at the front end of the weighing device, a discharge pipe A of the reversing device is connected to the weighing device, and a discharge pipe B is connected to the variable temperature oil tank;

[0041] S4, the oil pump is started, the stop valve B is opened, the oil in the variable temperature oil tank enters the constant temperature device from the circulation pipeline A, the pipeline connected to the instrument is kept in a constant temperature state, and then the oil enters the reversing device from the branch pipeline;

[0042] S5, the reversing device is driven to discharge the oil from the discharge pipe A to the weighing device, the oil reaches a preset liquid level and stabilizes, and then reading is performed, and meanwhile, the reversing device is driven to discharge the oil from the discharge pipe B to the variable temperature oil tank, so that the circulation of the oil in the pipeline is maintained;

[0043] S6, after the weighing device completes reading and the internal oil is discharged, the reversing device is driven to discharge the oil from the discharge pipe A to the weighing device for weighing, and steps S5 and S6 are repeated to realize continuous measurement of the weighing device.

[0044] When the weighing device or the reversing device fails or is temporarily repaired, the stop valve A is opened and the stop valve B is closed, the oil is stopped from being supplied to the weighing device and the reversing device, and the oil in the system is kept in a circulating state.

[0045] A filter is arranged on the circulation pipeline A between the oil pump and the variable temperature oil tank, a filter is arranged on the circulation pipeline A between the oil pump and the constant temperature device, the two filters are used to filter impurities in the oil, and a one-way valve C is arranged between the oil pump and the filter in the middle, and the one-way valve C is used to prevent the oil in the circulation pipeline from flowing back to the variable temperature oil tank when the system is stopped.

[0046] An overflow pipe is arranged between the middle of the circulation pipeline A and the variable temperature oil tank, an overflow valve is arranged on the overflow pipe, when the oil flow rate in the circulation pipeline A is too fast to cause excessive pressure, the oil flows back to the variable temperature oil tank through the overflow valve from the overflow pipe, so as to maintain the stability of the oil pressure in the circulation pipeline, ensure the accuracy of the calibration measurement, and a standby interface is further arranged on the circulation pipeline A.

[0047] The thermostatic device includes an oil bath and instrument clamping fittings installed within the oil bath. The instrument clamping fittings on both sides are connected to thermometers for real-time monitoring of the oil temperature in the pipeline. A pressure gauge is also connected to the instrument clamping fittings for real-time monitoring of the pipeline pressure. One end of the instrument clamping fitting is connected to circulation pipeline A, with a regulating valve A at the connection point; the other end is connected to circulation pipeline B, with a regulating valve A at the connection point. The flow rate of the oil entering the instrument clamping fitting is adjusted by these two regulating valves A. The instrument is clamped in the middle of the instrument clamping fitting and submerged in the oil in the oil bath. An inlet pipe is connected between circulation pipeline A and one end of the oil bath, and a regulating valve B is installed on the inlet pipe. The flow rate of the oil entering the oil bath is regulated by regulating valve B. Since the temperature in the oil bath is lost relatively quickly, the opening of regulating valve B is set to be greater than that of regulating valve A to accelerate the replacement speed of the oil in the oil bath. The heat exchange rate in the oil bath is greater than the heat exchange rate of the oil in the instrument clamping fittings, making the temperature of the oil in the instrument clamping fittings and the oil in the oil bath closer to the temperature of the oil in the variable temperature oil tank. The temperature difference between the circulation pipeline, the instrument clamping fittings, and the variable temperature oil tank is smaller, resulting in higher measurement accuracy. An overflow port is provided at the upper part of the other end of the oil bath. The oil enters the oil bath from the inlet pipe and flows back to the variable temperature oil tank from the overflow port, realizing the circulation channel of the oil in the oil bath.

[0048] The weighing device includes a weighing scale and a piston-type oil extraction mechanism. An oil container is placed on the weighing scale. The piston-type oil extraction mechanism includes piston cylinder A, piston cylinder B, piston cylinder C, and a reversing valve connected to a high-pressure air source. Piston cylinder A has a first inlet and a second inlet at its two ends, piston cylinder B has a third inlet and a third inlet at its lower end, and piston cylinder C has a fourth inlet and a fifth inlet and a fourth inlet and a fifth inlet at its two ends. The piston rod extending downward from piston cylinder A and the piston rod extending upward from piston cylinder B are coaxially and fixedly connected by a coupling. Piston cylinder A drives the piston of piston cylinder B to move, performing oil suction or oil discharge operations.

[0049] A return pipe is connected to the variable temperature oil tank. The outer end of the return pipe is fixedly connected to the lower end of the piston rod of piston cylinder C. The piston rod is located directly above the oil container. A suction pipe is connected between the middle of the return pipe and the third inlet / outlet. One-way valve A and one-way valve B are respectively installed on the return pipes on both sides of the suction pipe. One-way valve A and one-way valve B are in the same direction. A first high-pressure gas pipe is connected between the first inlet / outlet and the fourth inlet / outlet. A second high-pressure gas pipe is connected between the second inlet / outlet and the third inlet / outlet. A reversing valve is connected between the first high-pressure gas pipe and the second high-pressure gas pipe through a high-pressure gas pipe. The reversing valve is used to switch the high-pressure gas between the first high-pressure gas pipe and the second high-pressure gas pipe. The reversing valve is also provided with a vent that communicates with the atmosphere to release the backflowing high-pressure gas.

[0050] The asymmetric reversing mechanism comprises a bidirectional cylinder installed in the middle of a support plate, a herringbone reversing pipe arranged at the lower end of the support plate, a sliding gap with the same length direction as the extension direction of the bidirectional cylinder arranged at one end of the middle of the support plate, a photoelectric probe fixedly connected to the bottom surface of the support plate, an outer end of the photoelectric probe being provided with a photosensitive groove corresponding to the sliding gap, photosensitive parts being correspondingly arranged on the two side walls of the photosensitive groove, and a vertical pipe being arranged between the sliding gap and the photosensitive groove and extending into the upper part of the herringbone reversing pipe; a liquid discharge pipe A and a liquid discharge pipe B are connected to the lower part of the herringbone reversing pipe, an extension rod of the bidirectional cylinder is fixedly connected to an oil pipe joint, the oil pipe joint is connected to a branch pipeline, and the oil pipe joint is provided as a quick connection joint.

[0051] The principle of the reversing device is that the bidirectional cylinder drives the vertical pipe to reciprocally slide in the photosensitive groove and correspond to the lower liquid discharge pipe A or the lower liquid discharge pipe B, oil liquid enters the liquid discharge pipe A or the liquid discharge pipe B from the vertical pipe, the positioning of the vertical pipe to the liquid discharge is realized by the photosensitive part of the photosensitive groove, the vertical pipe moves outward to block the photosensitive part, and then corresponds to the lower liquid discharge pipe A, the photoelectric probe transmits the position signal to the controller of the bidirectional cylinder, the cylinder stops working, and the vertical pipe stops working, the vertical pipe moves inward to completely leave the photosensitive part, and then corresponds to the lower liquid discharge pipe B, the photoelectric probe transmits the position signal to the controller of the bidirectional cylinder, the cylinder stops working, and the vertical pipe stops working.

[0052] The bidirectional cylinder is controlled by a two-position three-way valve, a gas pipe A of the two-position three-way valve is connected to the inlet and outlet of one end of the bidirectional cylinder, a gas pipe B is connected to the inlet and outlet of the other end of the bidirectional cylinder, and an adjusting valve is further arranged at the connection position of the gas pipe and the bidirectional cylinder.

[0053] An adapter and a flexible pipe are arranged between the oil pipe joint and the branch pipeline, one interface of the adapter is connected to the branch pipeline, the other interface is connected to the oil pipe joint through the flexible pipe, the flexible pipe deforms along with the movement of the vertical pipe driven by the extension of the bidirectional cylinder, the connection between the vertical pipe and the branch pipeline is maintained, and the oil liquid is not interrupted.

[0054] The method and principle of continuous measurement of the weighing device and the reversing device are as follows:

[0055] First step, oil feeding and weighing: the bidirectional cylinder of the reversing device drives the vertical pipe to move outward and correspond to the lower liquid discharge pipe A, oil liquid enters the oil liquid container of the weighing device from the liquid discharge pipe A, the bidirectional cylinder drives the vertical pipe to move inward and correspond to the lower liquid discharge pipe B when the liquid level of the oil liquid reaches a predetermined position, the oil liquid enters the variable-temperature oil liquid tank from the liquid discharge pipe B for continuous circulation, and the reading is performed after the oil liquid in the oil liquid container is stable.

[0056] Second step, oil emptying (see the attached drawing) Figure 2): After reading the number, the reversing valve passes high-pressure gas from the second inlet and outlet to piston cylinder A and piston cylinder C through the second high-pressure gas pipe. The piston rod in piston cylinder C pushes the outer end of the return pipe into the oil container, and the piston rod in piston cylinder A pulls the piston in piston cylinder B upwards. Piston cylinder B generates negative pressure in the return pipe through the suction pipe, and one-way valve B blocks the return circuit of the piston cylinder B to which the oil in the variable-temperature oil tank is sucked, and the oil can only be sucked into piston cylinder B through one-way valve A.

[0057] Step 3, re-oil weighing (see attached Figure 3 ): After the oil in the oil tank is emptied, the bidirectional air cylinder drives the vertical pipe to correspond to the lower drain pipe A, and the oil re-enters the oil container. At the same time, the reversing valve passes high-pressure gas from the first inlet and outlet to piston cylinder A and piston cylinder C through the first high-pressure gas pipe. The piston rod of piston cylinder C pulls the return pipe out of the oil container (pulling out the return pipe is to avoid the interference of the return pipe in the oil container to the weighing, and to improve the accuracy of the weighing measurement). The piston rod of piston cylinder A presses the piston of piston cylinder B downwards, and the oil in piston cylinder B is pressed out to the return pipe. One-way valve A blocks the return circuit of the oil returning to the oil container, and the oil can only return to the variable-temperature oil tank from the return pipe through one-way valve B. After the oil is stable and the number is read, repeat the second step above to realize continuous reversing weighing.

[0058] The reversing device has fast reversing speed and small disturbance to the oil flow field. The oil entering the oil container of the weighing device has less wall-hanging amount, and the accuracy of the weighing measurement is higher. The three piston cylinders of the weighing device and the reversing valve are used in cooperation, which can realize the synchronization of the return pipe entering the oil container and the piston cylinder B extracting the oil, realize the synchronization of the weighing reading and the oil returning to the variable-temperature oil tank, and the whole action process is compact. Combined with the reversing mechanism, high-efficiency continuous weighing verification can be realized.

Claims

1. A calibration method for a variable temperature flow meter, characterized in that: Includes the following steps: S1. Connect circulation pipe A to the outlet of the variable temperature oil tank. Install an oil pump on circulation pipe A. Connect circulation pipe B to the inlet of the variable temperature oil tank. Install shut-off valve A at the connection between circulation pipe B and the variable temperature oil tank. Connect a thermostat between the outer ends of circulation pipe A and circulation pipe B. Install the instrument inside the thermostat. S2. A branch pipeline is connected between the middle of the circulating pipeline B and the variable temperature oil tank. A shut-off valve B is installed on this branch pipeline. A weighing device is connected to the branch pipeline. The weighing device includes a scale and a piston-type oil extraction mechanism. An oil container is placed on the scale. The piston-type oil extraction mechanism includes piston cylinder A, piston cylinder B, piston cylinder C, and a reversing valve connected to a high-pressure air source. Piston cylinder A has a first inlet and a second inlet at its two ends, piston cylinder B has a third inlet and a third inlet at its lower end, and piston cylinder C has a fourth inlet and a fifth inlet and a fifth inlet at its two ends. The piston rod extending downwards from piston cylinder A and the piston... The piston rod extending upward from piston cylinder B is coaxially fixedly connected; a return pipe is connected to the variable temperature oil tank, and the outer end of the return pipe is fixedly connected to the lower end of the piston rod of piston cylinder C. The piston rod is located directly above the oil container. A suction pipe is provided between the middle of the return pipe and the third inlet and outlet. One-way valve A and one-way valve B are provided on the return pipes on both sides of the suction pipe. A first high-pressure air pipe is provided between the first inlet and outlet and the fourth inlet and outlet. A second high-pressure air pipe is provided between the second inlet and outlet and the third inlet and outlet. The reversing valve is connected between the first high-pressure air pipe and the second high-pressure air pipe through the high-pressure air pipe. S3. Connect a reversing device to the branch pipe at the front end of the weighing device. The drain pipe A of the reversing device is connected to the weighing device, and the drain pipe B is connected to the temperature-controlled oil tank. S4. Start the oil pump and open the shut-off valve B. The oil in the variable temperature oil tank enters the constant temperature device from the circulation pipe A, keeping the pipeline at the instrument connection point at a constant temperature. Then, it enters the reversing device from the branch pipeline. S5. The drive reversing device discharges oil from drain pipe A into the weighing device. After the oil reaches the preset level and stabilizes, the reading is taken. At the same time, the drive reversing device discharges oil from drain pipe B into the temperature-controlled oil tank to maintain the circulation of oil in the pipeline. S6. After the weighing device completes the reading and drains the internal oil, drive the reversing device to drain the oil back into the weighing device from the drain pipe A for weighing. Repeat steps S5 and S6 to achieve continuous measurement by the weighing device.

2. The method for calibrating a variable temperature flow meter according to claim 1, characterized in that: The constant temperature device includes an oil bath and an instrument clamping pipe installed in the oil bath. One end of the instrument clamping pipe is connected to circulation pipe A and a regulating valve A is provided at the connection. The other end is connected to circulation pipe B and a regulating valve A is provided at the connection. The instrument is clamped in the middle of the instrument clamping pipe and is submerged in the oil in the oil bath.

3. The method for calibrating a variable temperature flow meter according to claim 2, characterized in that: A liquid inlet pipe is connected between one end of the circulation pipe A and the oil bath tank. A regulating valve B is installed on the liquid inlet pipe, and an overflow port is provided at the upper part of the other end of the oil bath tank.

4. The method for calibrating a variable temperature flow meter according to claim 1, characterized in that: The reversing device includes a bidirectional cylinder installed in the middle of a support plate and a herringbone reversing pipe located at the lower end of the support plate. A sliding notch is provided in the middle of the support plate at one end of the bidirectional cylinder, with the length direction aligned with the extension and retraction direction of the bidirectional cylinder. A photoelectric probe is fixedly connected to the bottom surface of the support plate. The outer end of the photoelectric probe is provided with a photosensitive groove corresponding to the upper and lower sides of the sliding notch. Photosensitive parts are provided on the two side walls of the photosensitive groove. A vertical pipe extending into the upper part of the herringbone reversing pipe is provided between the sliding notch and the photosensitive groove. Drainage pipe A and drainage pipe B are connected to the lower part of the herringbone reversing pipe. The outer end of the extension rod of the bidirectional cylinder is fixedly connected to the oil pipe joint, and the oil pipe joint is connected to the branch pipe.

5. The method for calibrating a variable temperature flow meter according to claim 4, characterized in that: An adapter and a flexible pipe are provided between the oil pipe joint and the branch pipeline. One interface of the adapter is connected to the branch pipeline, and the other interface is connected to the oil pipe joint via a flexible pipe.

6. The method for calibrating a variable temperature flow meter according to claim 5, characterized in that: The methods for continuous measurement of the weighing device and reversing device in S5 and S6 are as follows: The first step is oil inlet weighing: the bidirectional cylinder of the reversing device drives the vertical pipe to move outward to correspond with the lower drain pipe A. The oil enters the oil container of the weighing device from the drain pipe A. After the oil level reaches the predetermined position, the bidirectional cylinder drives the vertical pipe to move inward to correspond with the lower drain pipe B. The oil enters the variable temperature oil tank from the drain pipe B to continue circulating. The reading is taken after the oil level in the oil container stabilizes. The second step is to vent the oil: After reading the data, the reversing valve introduces high-pressure gas from the second inlet and outlet into piston cylinder A and from the fourth inlet and outlet into piston cylinder C through the second high-pressure gas pipe. The piston rod in piston cylinder C pushes the outer end of the return pipe into the oil container downward. The piston rod in piston cylinder A pulls the piston in piston cylinder B upward. Piston cylinder B generates negative pressure in the return pipe through the suction pipe. One-way valve B blocks the circuit where the variable temperature oil tank is sucked into piston cylinder B. The oil can only be sucked into piston cylinder B through one-way valve A. The third step is to refill and weigh the oil: After the oil in the oil tank is emptied, the bidirectional cylinder re-drives the vertical pipe to align with the lower drain pipe A, and the oil re-enters the oil container. At the same time, the reversing valve introduces high-pressure gas from the first inlet and outlet into piston cylinder A and from the fifth inlet and outlet into piston cylinder C through the first high-pressure gas pipe. The piston rod of piston cylinder C pulls the return pipe out of the oil container upward, and the piston rod of piston cylinder A presses down on the piston of piston cylinder B, forcing the oil in piston cylinder B out into the return pipe. The one-way valve A blocks the oil return circuit to the oil container, and the oil can only flow back to the variable temperature oil tank through the return pipe via the one-way valve B. After the oil stabilizes and the reading is completed, the second step above is repeated to achieve continuous reversing weighing.

7. The method for calibrating a variable temperature flow meter according to claim 1, characterized in that: A filter is installed on the circulation pipe A between the oil pump and the variable temperature oil tank, and a filter is installed on the circulation pipe A between the oil pump and the constant temperature device.

8. The method for calibrating a variable temperature flow meter according to claim 1, characterized in that: An overflow pipe is provided between the middle of the circulating pipeline A and the variable temperature oil tank, and an overflow valve is provided on the overflow pipe.

Images