Composite field flowmeter calibration method

Abstract

A composite on-site flow meter calibration method is disclosed. This method allows for measurement of individual instruments using standard instruments, and can switch between standard instruments and volumetric measuring devices for simultaneous measurement, as well as between standard instruments and gravimetric measuring devices for simultaneous measurement. Therefore, it enables free switching between various measuring devices for comparison of measurement values, solving the problem of large measurement errors caused by single measurement methods and greatly improving the accuracy of instrument calibration. Furthermore, the instrument clamping device in this calibration method can simultaneously clamp multiple instruments in series for measurement, resulting in high efficiency and allowing for easy adjustment of the clamping quantity as needed, demonstrating strong adaptability. The gravimetric measuring device in this calibration method can accommodate the efficient alternation of two weighing devices while ensuring a relatively stable liquid level in the oil tank, which is beneficial for flow stability during the weighing process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of instrument measurement, in particular to a composite field flowmeter calibration method. BACKGROUND

[0002] Flowmeters need to be measured and calibrated for accuracy when they are shipped, and they also need to be regularly checked and calibrated for accuracy during use. Common methods for flowmeter calibration include volumetric method, mass method, and standard instrument method.

[0003] The standard instrument method has the advantages of low cost, simple structure, easy operation, short construction period, wide flow range, and high efficiency, but it has high uncertainty and low accuracy. The mass method involves discharging oil into a weighing container, and the impact of the oil will cause the electronic scale below to vibrate, prolonging the time for stable reading and reducing the efficiency of flowmeter calibration. In the volumetric method, the temperature of the oil is not consistent with the temperature of the tank and the environment, and the temperature will change slowly during measurement, requiring constant temperature correction. In addition, the use of standard metal containers as volume standards is affected by factors such as thermal expansion and contraction, resulting in large measurement errors. It can be seen that various single measurement methods have defects and large measurement errors.

[0004] In addition, existing clamping devices have limited capacity for clamping measurement instruments, and cannot adjust the number of clamped instruments according to demand, which has poor adaptability, a complicated operation process, and the problem of instruments falling due to reverse locking, which needs to be improved. SUMMARY

[0005] To solve the above problems, the present application provides a composite field flowmeter calibration method.

[0006] The technical solution of the present application is a composite field flowmeter calibration method, comprising the following steps:

[0007] Installing each calibration device

[0008] S1, connecting a first circulating pipeline at the outlet of the oil tank and a second circulating pipeline at the inlet, installing an instrument clamping device between the first and second circulating pipelines, and clamping the instrument under test and the standard instrument in the instrument clamping device;

[0009] S2, connecting a volumetric measurement device on a circulating branch A in the middle of the second circulating pipeline, and connecting a second stop valve between the measurement device and the circulating branch A of the second circulating pipeline;

[0010] S3, connecting a weight measuring device on the circulation branch B in parallel with the middle part of the second circulation pipeline, and connecting a third stop valve between the weight measuring device and the circulation branch B of the second circulation pipeline;

[0011] S4, connecting an oil pump at the connection between the first circulation pipeline and the oil tank, and connecting a first stop valve at the connection between the second circulation pipeline and the oil tank;

[0012] Calibration by the standard meter

[0013] S5, closing the second stop valve and the third stop valve, opening the first stop valve, starting the oil pump, and the oil in the oil tank is pumped out through the clamped meter under test and the standard meter, and then flows back to the oil tank, and the flow values of the standard meter and the meter under test are read for calibration;

[0014] Composite calibration by the standard meter and the volumetric measuring device

[0015] S6, closing the first stop valve and the third stop valve, opening the second stop valve, starting the oil pump, and the oil in the oil tank is pumped out through the clamped meter under test and the standard meter, and then enters the volumetric measuring device of the circulation branch A, and the flow values of the meter under test and the standard meter are read, and the flow value of the volumetric measuring device is converted for composite calibration;

[0016] Composite calibration by the standard meter and the weight measuring device

[0017] S7, closing the first stop valve and the second stop valve, opening the third stop valve, starting the oil pump, and the oil in the oil tank is pumped out through the clamped meter under test and the standard meter, and then enters the weight measuring device of the circulation branch B, and the flow values of the meter under test and the standard meter are read, and the flow value of the weight measuring device is converted for composite calibration.

[0018] Preferably, in step S6, the standard meter on the clamping device is removed to perform single calibration measurement of the volumetric measuring device.

[0019] Preferably, in step S7, the standard meter on the clamping device is removed to perform single calibration measurement of the weight measuring device.

[0020] Preferably, the instrument clamping device comprises a clamping base, a fixed pipe, an intermediate pipe, an extension pipe, one end of the clamping base is provided with a fixed support, the fixed pipe is transversely fixedly installed at the upper end of the fixed support, the outer end of the fixed pipe is connected with the first circulating pipeline, the inner end of the fixed pipe is coaxially sleeved with a clamping joint, the middle of the clamping base is provided with a guide rail, a plurality of intermediate supports are slidably connected to the middle part of the guide rail through sliding blocks, the upper end of the intermediate support is transversely fixedly installed with the intermediate pipe, the two ends of the intermediate pipe are coaxially sleeved with clamping joints, the other end of the clamping base is provided with a clamping support which is slidably connected to the guide rail through a sliding block, the upper end of the clamping support is provided with an extension driving device, the extension driving device is internally installed with the extension pipe, the outer end of the extension pipe is connected with the second circulating pipeline through a metal hose, the inner end of the extension pipe is coaxially sleeved with a clamping joint; the fixed pipe, the plurality of intermediate pipes and the extension pipe are coaxially corresponding;

[0021] The upper surface of the clamping base is provided with a positioning rack extending to both ends of the clamping base along the length direction, the outer side surface of the clamping support is hingedly connected with a check plate, the lower end of the check plate is clamped into the right-angle tooth groove of the positioning rack.

[0022] Preferably, the extension driving device comprises an annular turbine and a worm which are installed in the housing support and are mutually meshed, the extension pipe is provided with external threads on the outer side surface, the housing support is fixed on the upper end of the clamping support, the two end surfaces of the annular turbine are coaxially fixedly connected with hollow shafts, the two hollow shafts are rotatably connected with the side walls at both ends of the housing support through bearings, the middle hole of the annular turbine is provided with internal threads, the extension pipe is sleeved in the middle hole of the annular turbine and the external threads of the extension pipe are meshed with the internal threads of the middle hole, the upper end of the housing support is provided with a motor, the driving shaft of the motor is coaxially fixedly connected with the shaft of the worm.

[0023] Preferably, the volumetric measuring device comprises a volumetric piston cylinder and a conical pneumatic reversing valve,

[0024] The conical pneumatic reversing valve comprises a cylinder, two identical valve bodies A, two identical valve bodies B, the two valve bodies A are coaxially and symmetrically sealedly connected with both ends of the cylinder, the outer end surface center of the valve body A is coaxially provided with a cylindrical cavity A, the inner end surface center of the cylindrical cavity A is provided with a shaft hole A, the side wall of the valve body A is provided with an inlet and outlet which is in communication with the middle of the cylindrical cavity A along the radial direction, the inlet and outlet on one side of the valve body A is set as the first valve body inlet and outlet, the inlet and outlet on the other side of the valve body A is set as the second valve body inlet and outlet;

[0025] Two valve body B is coaxial and symmetrically sealed connected to the outer end of two valve body A, the inner side surface center of valve body B is provided with a valve core cavity along the axial direction, the side wall of valve body B is provided with an inlet and outlet along the radial direction and in communication with the valve core cavity, one side of the inlet and outlet is provided as a liquid outlet, and the other side of the inlet and outlet is provided as a liquid inlet, the inner end surface center of the valve core cavity is coaxially provided with a cylindrical cavity B, and the side wall of valve body B is provided with an inlet and outlet in communication with the cylindrical cavity B, one side of the inlet and outlet on valve body B is provided as a third valve body inlet and outlet, and the other side of the inlet and outlet on valve body B is provided as a fourth valve body inlet and outlet, and the inner end surface center of the cylindrical cavity B is provided with a shaft hole B;

[0026] The valve core comprises two identical valve core parts, which are symmetrically installed on both sides of the valve body, and the valve core part comprises two symmetrically arranged conical valves with a certain interval, the two conical valves are fixedly connected into one body by a valve shaft coaxially arranged between the two conical valves, the inner end of the valve shaft extends into the cylinder through the shaft hole B and is fixedly connected with the center of the piston body in the cylinder, the outer end of the valve shaft is out of the shaft hole B, the conical valve is located in the valve core cavity, and the tip of the conical valve faces the cylindrical cavity A or the cylindrical cavity B; the end surface of the conical valve is coaxially provided with a circular baffle, and the diameter of the circular baffle is greater than the diameter of the cylindrical cavity B;

[0027] The volumetric piston cylinder comprises a cylinder body, end covers coaxially fixedly connected to both ends of the cylinder body, and a piston installed in the cylinder body, the inner end surface of the end cover is provided with a circular truncated cone deceleration groove along the axial direction, the bottom surface center of the circular truncated cone deceleration groove is provided with a sliding hole penetrating through the end cover, the side wall of one end of the cylinder body is provided with two cylinder inlets and outlets, which are a first cylinder inlet and outlet and a second cylinder inlet and outlet, respectively, and the side wall of the other end of the cylinder body is provided with two cylinder inlets and outlets along the radial direction, which are a third cylinder inlet and outlet and a fourth cylinder inlet and outlet, respectively; the centers of the two end surfaces of the piston are symmetrically provided with two piston rods along the axial direction, the outer ends of the two piston rods respectively match and extend out of the sliding holes at both ends of the cylinder body, and the inner end of the piston rod is coaxially fixedly connected with a circular deceleration disc, and a certain interval is provided between the deceleration disc and the piston disc;

[0028] The first valve body inlet and outlet and the third cylinder inlet and outlet are connected by pipeline A, the second valve body inlet and outlet and the fourth cylinder inlet and outlet are connected by pipeline B, the third valve body inlet and outlet and the first cylinder inlet and outlet are connected by pipeline C, and the fourth valve body inlet and outlet and the second cylinder inlet and outlet are connected by pipeline D, the liquid inlet is connected with the second circulating pipeline, and the liquid outlet is connected with the oil tank through the liquid discharge pipe.

[0029] Preferably, the specific measurement method of the volumetric measurement device in S6 is:

[0030] When the cylinder driving valve core moves to one side, the second valve body inlet and outlet and the third valve body inlet and outlet are closed, the first valve body inlet and outlet and the fourth valve body inlet and outlet are opened, pipe C and pipe B are closed, and pipe A and pipe D are opened; the oil in the circulation branch A enters the valve core cavity from the inlet, is discharged from the fourth valve body inlet and outlet through the cylindrical cavity B, then enters the cylinder through pipe D and the second cylinder inlet and outlet to drive the piston to move, the piston compresses the internal oil to enter the valve core cavity from pipe A and the first valve body inlet and outlet, and then is discharged from the outlet into the oil tank; the process of moving the cylinder driving valve core to the other side to realize the reversing is the same as the above method.

[0031] Then the movement distance of the piston is measured to determine the volume V of the oil entering the cylinder, and the average flow through the cylinder is determined by the oil inlet time t.

[0032] Preferably, the side wall of the cylinder is uniformly distributed with a plurality of axial constant temperature holes, the two ends of the constant temperature holes pass through the two end faces of the cylinder, and the annular pad plate is coaxially and fixedly connected between the end cover and the cylinder, the inner end face of the annular pad plate is coaxially provided with an annular groove covering the end port of the constant temperature hole in the middle, and the annular groove and the end face of the cylinder form an annular chamber, the side surface of the annular pad plate at one end of the cylinder is provided with a constant temperature oil inlet and outlet penetrating into the annular groove, and the side surface of the annular pad plate at the other end of the cylinder is provided with a constant temperature oil inlet and outlet penetrating into the annular groove.

[0033] Preferably, the gravimetric measuring device comprises a reversing device and the same weighing device A and weighing device B, the middle of one end of the reversing device is connected with the circulation branch B, the reversing device is connected with two liquid outlet pipes for discharging the switched liquid, which are provided as liquid outlet pipe A and liquid outlet pipe B, the weighing device A comprises a weighing scale A and a weighing tank A placed on the weighing scale A through a support, the tank bottom of the weighing tank A is provided with an outlet pipe A connected to the oil tank, the outlet pipe A is provided with a pneumatic valve A, the weighing tank A is located directly below the liquid outlet pipe A, and the components of the weighing device are provided as a weighing tank B, a weighing scale B, an outlet pipe B and a pneumatic valve B, and the weighing tank B is located directly below the liquid outlet pipe B.

[0034] Preferably, the specific measurement method of the gravimetric measuring device in S7 is that the oil enters the weighing tank A from the liquid outlet pipe A through the reversing device, at this time the weighing scale A works and the pneumatic valve A is closed, after the oil in the weighing tank A is collected to the set value of the weighing scale A, the reversing device switches the oil to the liquid outlet pipe B, the oil enters the weighing tank B from the liquid outlet pipe B, at this time the weighing scale B works and the pneumatic valve B is closed; during the switching process, the weighing tank A and the weighing scale A tend to be stable, the weighing weight of the weighing scale A is read, then the pneumatic valve A is opened to quickly empty the oil and is closed, and the weighing scale A is cleared; the weighing device B is weighed and cleared according to the steps of the weighing device A, and the oil is continuously weighed.

[0035] The beneficial technical effects of the present application are:

[0036] The application discloses a composite on-site flow meter calibration method, which can measure single instrument by a standard instrument, can switch the standard instrument and a volumetric measuring device to synchronous measurement, can switch the standard instrument and a gravimetric measuring device to synchronous measurement, can freely switch measurement between various measuring devices for comparison of measurement values, can solve the problem of large measurement value error caused by defects of single measurement mode, and greatly improves the accuracy of instrument calibration; in addition, the instrument clamping device in the calibration method can simultaneously clamp and measure multiple instruments in series, is high in efficiency, can be conveniently adjusted in clamping quantity according to requirements, and is high in adaptability; the gravimetric measuring device in the calibration method can satisfy alternate high-efficiency operation of two weighing devices, can guarantee relative stability of the liquid level in an oil tank, and is beneficial to the stability of flow in the weighing process; the conical pneumatic reversing valve in the calibration method can control the reciprocating operation of the volumetric piston cylinder to measure the volume of oil, and can continuously discharge the measured oil into the oil tank, realizes circulation of the oil during measurement, and realizes continuous measurement of the instrument. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a system diagram of the whole application (the direction of the arrow in the figure is the flow direction of oil in the conical pneumatic reversing valve and the volumetric piston cylinder);

[0038] Figure 2 is Figure 1 a structure schematic view of the reversing valve and the piston cylinder in

[0039] Figure 3 is a structure schematic view of the gravimetric measuring device;

[0040] Figure 4 is a structure schematic view of the conical pneumatic reversing valve;

[0041] Figure 5 is a structure schematic view of the volumetric piston cylinder;

[0042] Figure 6 is Figure 5 an A-A sectional view of

[0043] Figure 7 is Figure 5 a B-B sectional view of

[0044] Figure 8 is a structure schematic view of the annular gasket;

[0045] Figure 9 is a structure schematic view of the instrument clamping device;

[0046] Figure 10is a front view structural diagram of the instrument clamping device after clamping the instrument under test;

[0047] Figure 11 is Figure 10 is a front view structural diagram of the instrument clamping device after clamping the instrument under test;

[0048] Figure 12 is Figure 11 is a front view structural diagram of the instrument clamping device after clamping the instrument under test;

[0049] Figure 13 is Figure 11 is a front view structural diagram of the instrument clamping device after clamping the instrument under test;

[0050] Figure 14 is a front view structural diagram of the instrument clamping device after clamping the instrument under test;

[0051] Figure 15 is a front view structural diagram of the instrument clamping device after clamping the instrument under test; Figure 14

[0052] is a front view structural diagram of the instrument clamping device after clamping the instrument under test; Figure 16 Figure 15 is a front view structural diagram of the instrument clamping device after clamping the instrument under test;

[0053] Figure 17 is a front view structural diagram of the instrument clamping device after clamping the instrument under test;

[0054] Figure 18 is a front view structural diagram of the instrument clamping device after clamping the instrument under test;

[0055] Figure 19 Figure 18 is a front view structural diagram of the instrument clamping device after clamping the instrument under test;

[0056] Figure 20 is a front view structural diagram of the instrument clamping device after clamping the instrument under test.

[0057] In the figure, 01. oil tank, 11. first circulating pipeline, 111. oil pump, 112. filter, 113. overflow pipeline, 114. overflow valve, 12. second circulating pipeline, 121. circulation branch A, 122. circulation branch B, 123. second stop valve, 124. third stop valve, 125. first stop valve, 126. standard instrument, 13 pipeline A, 14. pipeline B, 15. pipeline C, 16. pipeline D, 17. one-way valve, 18. rectifier, 19. thermometer, 20. spare interface,

[0058] ​​02. instrument clamping device, 21. instrument under test, 22. clamping base, 221. guide rail, 222. sliding block, 23. fixed support, 231. fixed tube, 24. intermediate support, 241. intermediate tube, 25. clamping support, 251. telescopic tube, 252. external thread, 26. clamping joint, 261. sleeve joint, 262. sleeve, 263. positioning ring, 27. sealing ring with circular cross section, 28. annular groove with V-shaped cross section, 29. telescopic drive, 291. motor, 292. annular turbine, 293. hollow shaft, 294. bearing, 295. internal thread, 296. worm, 297. housing support, 301. positioning rack, 302. right-angle tooth slot, 303. non-return plate, 304. positioning ring, 301. positioning rack, 302. right-angle tooth slot, 303. non-return plate, 304. positioning ring,

[0059] 31. conical pneumatic directional valve,

[0060] 311. cylinder, 312. piston, 32. valve body A, 321. cylindrical cavity A, 322. first valve body inlet and outlet, 323. second valve body inlet and outlet, 33. valve body B, 331. spool cavity, 332. third valve body inlet and outlet, 333. fourth valve body inlet and outlet, 334. liquid inlet, 335. liquid outlet, 336. cylindrical cavity B, 341. conical valve, 342. circular baffle, 343. spool shaft,

[0061] 35. positive displacement piston cylinder,

[0062] 351. cylinder body, 352. first cylinder inlet and outlet, 353. second cylinder inlet and outlet, 354. third cylinder inlet and outlet, 355. fourth cylinder inlet and outlet, 356. thermostatic hole, 37. end cover, 371. circular truncated cone deceleration groove, 38. piston, 381. piston rod, 382. circular deceleration disc, 383. rubber deceleration pad, 39. annular pad plate, 391. annular groove, 392. annular chamber, 393. thermostatic oil inlet and outlet,

[0063] 04. gravimetric measuring device, 41. commutator, 411. liquid outlet pipe A, 412. liquid outlet pipe B, 42. weighing device A, 421. scale A, 422. weighing box A, 423. outlet pipe A, 424. pneumatic valve A, 43. weighing device B, 431. scale B, 432. weighing box B, 433. outlet pipe B,

[0064] 434. pneumatic valve B. DETAILED DESCRIPTION

[0065] Example One, see the accompanying drawings Figure 1 - 20, a composite field flowmeter calibration method, comprising the following steps:

[0066] Installation of each calibration device

[0067] S1, connecting a first circulation pipeline at the outlet of the oil tank and a second circulation pipeline at the inlet, installing an instrument clamping device between the first circulation pipeline and the second circulation pipeline, clamping the inspected instrument and the standard instrument in the instrument clamping device;

[0068] S2, connecting a circulation branch A in parallel at the middle of the second circulation pipeline, connecting a volumetric measuring device on the circulation branch A, and connecting a second stop valve on the circulation branch A between the measuring device and the second circulation pipeline;

[0069] S3, connecting a circulation branch B in parallel at the middle of the second circulation pipeline, connecting a gravimetric measuring device on the circulation branch B, and connecting a third stop valve on the circulation branch B between the measuring device and the second circulation pipeline;

[0070] S4, connecting an oil pump at the connection between the first circulation pipeline and the oil tank, and connecting a first stop valve at the connection between the second circulation pipeline and the oil tank;

[0071] Calibration by the standard instrument

[0072] S5, closing the second stop valve and the third stop valve, opening the first stop valve, starting the oil pump, and pumping the oil in the oil tank through the clamped inspected instrument and the standard instrument and then back to the oil tank, reading the flow values of the standard instrument and the inspected instrument for calibration;

[0073] Composite calibration by the standard instrument and the volumetric measuring device

[0074] S6, closing the first stop valve and the third stop valve, opening the second stop valve, starting the oil pump, and pumping the oil in the oil tank through the clamped inspected instrument and the standard instrument, then into the volumetric measuring device of the circulation branch A, reading the flow values of the inspected instrument and the standard instrument, and converting the flow value of the volumetric measuring device for composite calibration;

[0075] Composite calibration by the standard instrument and the gravimetric measuring device

[0076] S7, closing the first stop valve and the second stop valve, opening the third stop valve, starting the oil pump, and pumping the oil in the oil tank through the clamped inspected instrument and the standard instrument, then into the gravimetric measuring device of the circulation branch B, reading the flow values of the inspected instrument and the standard instrument, and converting the flow value of the gravimetric measuring device for composite calibration.

[0077] In step S6, removing the standard instrument from the clamping device can perform separate calibration measurement of the volumetric measuring device; in step S7, removing the standard instrument from the clamping device can perform separate calibration measurement of the gravimetric measuring device.

[0078] The overflow pipe is connected between the first circulation pipe and the oil tank, and an overflow valve is arranged on the overflow pipe.

[0079] The first circulation pipe between the oil pump and the oil tank is provided with a filter, and the first circulation pipe between the oil pump and the instrument clamping device is provided with a filter.

[0080] The first circulation pipe is connected with the instrument clamping device, and a rectifier is arranged at the connection position of the first circulation pipe and the instrument clamping device.

[0081] The instrument clamping device comprises a clamping base, a fixed pipe, an intermediate pipe, and an extension pipe.

[0082] The upper surface of the clamping base is provided with a positioning rack extending to both ends of the clamping base along the length direction.

[0083] The telescopic drive device comprises an annular turbine and a worm meshing with each other, installed in a shell support, a telescopic pipe member provided with external threads on the outer side, the shell support is fixed on the upper end of the clamping support, both end faces of the annular turbine are coaxially fixedly connected with hollow shafts, the two hollow shafts are rotatably connected with the side walls at both ends of the shell support through bearings, the middle hole of the annular turbine is provided with internal threads, the telescopic pipe member is sleeved in the middle hole of the annular turbine through the hollow shafts and the external threads of the telescopic pipe member are engaged with the internal threads of the middle hole, the worm drives the annular turbine to rotate, the annular turbine drives the telescopic pipe member provided with external threads to move through the internal threads of the middle hole of the annular turbine, the telescopic pipe member makes telescopic movement in the hollow shafts, each instrument is clamped and the self-locking of the clamping force can be realized, even if a sudden failure such as power failure occurs, the clamping effect can still be ensured, accidents such as instrument loosening or even falling caused by clamping failure are avoided, the upper end of the shell support is provided with a motor, and the driving shaft of the motor is coaxially fixedly connected with the shaft of the worm.

[0084] The inner end portions of the fixed pipe member and the telescopic pipe member are coaxially provided with positioning ring a, the two ends of the middle pipe member are coaxially provided with positioning ring a, the clamping adapter comprises a sleeve adapter and a sleeve pipe coaxially fixedly connected as a whole, the clamping adapter is coaxially sleeved in the fixed pipe member, the middle pipe member and the telescopic pipe member through the sleeve pipe, the outer end portion of the sleeve pipe is coaxially provided with positioning ring b corresponding to the positioning ring a, the sleeve adapter is used for butt joint with the interface of the instrument, and the clamping adapter can be quickly connected or detached with the fixed pipe member, the middle pipe member and the telescopic pipe member through the sleeve pipe.

[0085] The clamping adapter is provided in multiple specifications, different pipe members are replaced and correspond to clamping adapters of different specifications, so that different models of instruments are adapted, and thermometers are arranged on the fixed pipe member, the middle pipe member and the telescopic pipe member.

[0086] The inner side faces of the positioning ring a and the positioning ring b are both provided with annular grooves with V-shaped cross sections in the middle portions, a sealing ring with a circular cross section is sleeved between the two annular grooves with V-shaped cross sections, the clamping adapter and the pipe member are sealed through the annular sealing ring made of rubber, air leakage is avoided, and the phenomenon that the nuclear calibration is inaccurate is avoided, the sealing ring and the annular groove can also play a centering role, and it is ensured that each clamping adapter can be coaxially corresponding.

[0087] The working process and principle of this instrument clamping device are as follows: When clamping instruments, the spacing between the intermediate support, clamping support, and fixed support is adjusted on the clamping base. The instrument to be tested and the standard instrument are clamped between the clamping joints of each pipe fitting. Then, the telescopic drive device drives the telescopic pipe fitting to push the instrument inward, clamping several instruments simultaneously between each pipe fitting. Multiple instruments are connected in series for measurement. At the same time, the number of intermediate supports and intermediate pipe fittings can be selected according to the requirements to adjust the number of clamped instruments. After the position of the clamping support is adjusted accordingly, the clamping support is limited by the check plate and the positioning rack. This clamping pipeline system has simple operation steps, can flexibly adjust the number of instruments clamped and calibrated, and can adapt to the requirements of large-scale and high-efficiency production.

[0088] The volumetric measuring device includes a volumetric piston cylinder and a conical pneumatic directional valve.

[0089] The conical pneumatic directional valve includes a cylinder, two identical valve bodies A, and two identical valve bodies B. The two valve bodies A are coaxially and symmetrically sealed to both ends of the cylinder. A cylindrical cavity A is coaxially located at the center of the outer end face of valve body A, and a shaft hole A is located at the center of the inner end face of the cylindrical cavity A. The sidewalls of valve body A have radially arranged inlet and outlet connections communicating with the center of the cylindrical cavity A. The inlet and outlet on one side of valve body A are designated as the first valve body inlet and outlet, and the inlet and outlet on the other side of valve body A are designated as the second valve body inlet and outlet. The two valve bodies B are coaxially and symmetrically sealed to the outer ends of the two valve bodies A. The valve body B has a valve core cavity axially extending inward from the center of its inner surface. The valve body B has an inlet and outlet that communicate with the center of the valve core cavity along its side wall in the radial direction. One inlet and outlet on one side is a drain port, and the other inlet and outlet on the other side is an inlet. The valve core cavity has a cylindrical cavity B coaxially arranged at the center of its inner end face. The valve body B has an inlet and outlet that communicate with the center of the cylindrical cavity B along its side wall in the radial direction. The inlet and outlet on one side of the valve body B is a third valve body inlet and outlet, and the inlet and outlet on the other side of the valve body B is a fourth valve body inlet and outlet. The cylindrical cavity B has a shaft hole B at the center of its inner end face.

[0090] The valve core includes two identical valve core components, which are symmetrically installed on both sides inside the valve body. Each valve core component includes two symmetrically arranged conical valves with a certain distance between them. The two conical valves are coaxially and fixedly connected as one unit by a valve core shaft. The inner end of the valve core shaft passes through shaft hole B and extends into the cylinder, and is fixedly connected to the center of the piston body inside the cylinder. The outer end of the valve core shaft exits from shaft hole B. The conical valves are located in the valve core cavity, with the tips of the conical valves facing cylindrical cavity A or cylindrical cavity B. As the conical valves enter or leave the cylindrical cavity, the flow area of ​​the cylindrical cavity gradually increases or decreases, which can precisely control the gas flow rate. A circular baffle is coaxially provided on the end face of the conical valve. The diameter of the circular baffle is larger than the diameter of cylindrical cavity B, and the cylindrical cavity is completely sealed by the circular baffle.

[0091] A positive displacement piston cylinder includes a cylinder body, end caps coaxially fixedly connected to both ends of the cylinder body, and a piston installed inside the cylinder body. The inner end face of the end cap has an axially oriented frustum-shaped reduction groove, and the center of the bottom surface of the frustum-shaped reduction groove has a sliding hole penetrating the end cap. One end sidewall of the cylinder body has two cylinder inlets / outlets, designated as a first cylinder inlet / outlet and a second cylinder inlet / outlet, respectively. The other end sidewall has two radially oriented cylinder inlets / outlets, designated as a third cylinder inlet / outlet and a fourth cylinder inlet / outlet, respectively. Two piston rods are symmetrically arranged axially at the centers of both end faces of the piston, and the outer ends of the two piston rods are respectively matched with slave cylinders. The piston rod has sliding holes at both ends, and a circular speed reducer is coaxially fixed to the inner end of the piston rod. There is a certain distance between the speed reducer and the piston disc. After the circular speed reducer enters the frustum-shaped speed reducer groove, a closed space is formed between them. The liquid in the space generates resistance to the speed reducer. As the depth of the speed reducer increases, the gap between the speed reducer groove and the speed reducer gradually decreases, and the resistance gradually increases. This rapidly reduces the piston's movement speed, avoids collision between the piston and the end cover, reduces wear between the piston, cylinder body, and end cover, and can improve the accuracy of piston cylinder measurement and extend service life.

[0092] The angle between the sidewall of the frustum-shaped deceleration groove and its centerline is set to 5°. After testing, it was found that the deceleration groove has the best deceleration effect on the deceleration disc when the angle is set to 5°.

[0093] The diameter of the circular speed reducer is the same as the diameter of the bottom of the frustum-shaped speed reducer groove, which increases the moving distance of the speed reducer within the speed reducer groove and increases the stroke of the speed reducer in compressing the enclosed space.

[0094] The outer end face of the circular speed reducer is covered with a rubber speed reducer pad. The circular speed reducer is made of metal. When the speed reducer reaches the bottom of the speed reducer groove, the rubber speed reducer pad first contacts the bottom of the groove, which can play a secondary speed reduction buffer role.

[0095] The cylinder body has several axial thermostatic holes evenly distributed on its side wall. The two ends of the thermostatic holes penetrate the two end faces of the cylinder body. An annular gasket is coaxially fixed between the end cap and the cylinder body. The annular gasket has an annular groove coaxially provided in the middle of its inner end face to cover the port of the thermostatic hole. An annular chamber is formed between the annular groove and the end face of the cylinder body. By setting the annular gasket, an annular chamber for distributing thermostatic oil is formed at the end of the cylinder body. This structure is easy to disassemble and maintain, and can ensure the structural strength of the cylinder body itself. The side of the annular gasket at one end of the cylinder body has a thermostatic oil inlet and outlet that penetrates to the annular groove. The side of the annular gasket at the other end of the cylinder body has a thermostatic oil inlet and outlet that penetrates to the annular groove. The thermostatic oil enters the annular chamber from the thermostatic oil inlet and outlet, enters the thermostatic hole from the annular chamber, and then exits from the thermostatic oil inlet and outlet of the annular chamber at the other end, forming a circulation of thermostatic oil and maintaining the cylinder body in a constant temperature state.

[0096] The inlet and outlet of the first valve body and the inlet and outlet of the third cylinder body are connected by pipe A; the inlet and outlet of the second valve body and the inlet and outlet of the fourth cylinder body are connected by pipe B; the inlet and outlet of the third valve body and the inlet and outlet of the first cylinder body are connected by pipe C; the inlet and outlet of the fourth valve body and the inlet and outlet of the second cylinder body are connected by pipe D; the liquid inlet is connected to the second circulation pipe; and the liquid outlet is connected to the oil tank through the liquid outlet pipe.

[0097] The specific measurement method of the volumetric measuring device in S6 is as follows: the cylinder drives the valve core to move to one side, closing the inlet and outlet of the second valve body and the inlet and outlet of the third valve body, and opening the inlet and outlet of the first valve body and the inlet and outlet of the fourth valve body. Pipes C and B are in a closed state, and pipes A and D are in an open state. The oil enters the valve core cavity from the inlet and is discharged from the inlet and outlet of the fourth valve body through the cylindrical cavity B. Then, it enters the cylinder body from pipe D and the inlet and outlet of the second cylinder body to drive the piston to move. The piston compresses the internal oil and enters the valve core cavity from pipe A and the inlet and outlet of the first valve body. Then, it is discharged into the oil tank from the outlet.

[0098] The process of the cylinder driving the valve core to move to the other side to achieve reversal is the same as the above steps. The volume V of oil entering the cylinder is determined by measuring the piston's movement distance, and the average flow rate through the cylinder is determined by the oil inlet time t.

[0099] The weight-measuring device includes a commutator and identical weighing devices A and B. One end of the commutator is connected to a circulation branch B. The commutator is connected to two outlet pipes for switching liquid discharge, designated as outlet pipe A and outlet pipe B. Weighing device A includes a weighing instrument A and a weighing box A placed on the weighing instrument A via a support. The bottom of the weighing box A has an outlet pipe A connected to an oil tank. A pneumatic valve A is installed on the outlet pipe A. The weighing box A is located directly below the outlet pipe A, and the outlet pipe A extends into the weighing box A but does not contact it to avoid affecting weighing accuracy. The components of the weighing device are designated as weighing box B, weighing instrument B, outlet pipe B, and pneumatic valve B. Weighing box B is located directly below the outlet pipe B, and the outlet pipe B extends into the weighing box B but does not contact it to avoid affecting weighing accuracy.

[0100] The specific measurement method of the weight-type measuring device in S7 is as follows: the oil enters the weighing box A from the outlet pipe A through the reversing device. At this time, the weighing instrument A is working and the pneumatic valve A is closed. After the oil in the weighing box A is collected to the set value of the weighing instrument A, the reversing device switches the oil to the outlet pipe B. The oil enters the weighing box B from the outlet pipe B. At this time, the weighing instrument B is working and the pneumatic valve B is closed. During the switching process, the weighing box A and the weighing instrument A tend to stabilize. The weighing weight of the weighing instrument A is read. Then, the pneumatic valve A is opened to quickly release the oil and then closed. The weighing instrument A is zeroed, so that the weighing device A returns to its initial state. The weighing device B weighs and returns to its initial state according to the steps of the weighing device A, so as to realize the continuous weighing of the oil.

[0101] This weight-based measuring device allows for the efficient alternating operation of two weighing units (improving weighing efficiency by more than 2 times compared to traditional weighing devices). It also enables unlimited accumulation of the weighed mass from both units; for example, five reversals of the commutator can increase the oil weighing capacity tenfold. This significantly improves the flow rate limit and weighing accuracy of the measuring device. Furthermore, because the weighing units are used alternately, the oil filling and draining processes of both units can be synchronized, ensuring a relatively stable oil level in the tank and facilitating stable flow rate during the weighing process.

Claims

1. A method for calibrating a composite field flow meter, characterized in that: Includes the following steps: Install all calibration devices S1. Connect the first circulation pipeline at the outlet of the oil tank and the second circulation pipeline at the inlet. Install an instrument clamping device between the first and second circulation pipelines and clamp the instrument under test and the standard instrument in the instrument clamping device. S2. A circulation branch A is connected in parallel in the middle of the second circulation pipeline. A volumetric measuring device is connected to circulation branch A. A second shut-off valve is connected to circulation branch A between the measuring device and the second circulation pipeline. S3. A parallel circulation branch B is connected in the middle of the second circulation pipeline. A weight-type measuring device is connected to circulation branch B. A third shut-off valve is connected to circulation branch B between the measuring device and the second circulation pipeline. S4. Connect an oil pump at the connection between the first circulation pipeline and the oil tank, and connect a first shut-off valve at the connection between the second circulation pipeline and the oil tank. Verification using standard instruments S5. Close the second and third shut-off valves, open the first shut-off valve, start the oil pump, and the oil in the oil tank is drawn out and flows back into the oil tank after passing through the clamped instrument under test and the standard instrument. Read the flow rate values ​​of the standard instrument and the instrument under test for verification. Composite verification was performed using standard instruments and volumetric measuring devices. S6. Close the first and third shut-off valves, open the second shut-off valve, and start the oil pump. The oil in the oil tank is drawn through the clamped instrument under test and the standard instrument, and then enters the volumetric measuring device in circulation branch A. Read the flow rate values ​​of the instrument under test and the standard instrument, and calculate the flow rate value of the volumetric measuring device for composite verification. The volumetric measuring device includes a volumetric piston cylinder and a conical pneumatic directional valve. The conical pneumatic directional valve includes a cylinder, two identical valve bodies A, and two identical valve bodies B. The outer end face of valve body A has a cylindrical cavity A coaxially arranged inward. The inlet and outlet on one side of valve body A are designated as the first valve body inlet and outlet, and the inlet and outlet on the other side of valve body A are designated as the second valve body inlet and outlet. The two valve bodies B are coaxially and symmetrically sealed to the outer ends of the two valve bodies A. The inner surface of valve body B has a valve core cavity axially arranged inward. The inner end face of the valve core cavity has a cylindrical cavity B coaxially arranged inward. The inlet and outlet on side valve body B are designated as the third valve body inlet and outlet, and the inlet and outlet on the other side valve body B are designated as the fourth valve body inlet and outlet. The cylinder drives the valve core to move to one side, closing the second and third valve body inlets and outlets and opening the first and fourth valve body inlets and outlets. Pipes C and B are closed, while pipes A and D are open. The oil in circulation branch A enters the valve core cavity from the inlet and exits through the cylindrical cavity B from the fourth valve body inlet and outlet. Then, it enters the cylinder from pipe D and the second cylinder body inlet and outlet, driving the piston to move. The piston compresses the internal oil, which enters the valve core cavity from pipe A and the first valve body inlet and outlet, and then exits from the outlet into the oil tank. The process of the cylinder driving the valve core to move to the other side to achieve reversal is described above. Then, the piston's movement distance is measured to determine the volume V of oil entering the cylinder, and the average flow rate through the cylinder is determined by the oil entry time t. Composite verification was performed using standard instruments and a gravimetric measuring device. S7. Close the first and second shut-off valves, open the third shut-off valve, start the oil pump, and the oil in the oil tank is drawn out through the clamped instrument under test and the standard instrument, and then enters the weight-type measuring device in circulation branch B. Read the flow rate values ​​of the instrument under test and the standard instrument, and calculate the flow rate value of the weight-type measuring device for composite verification.

2. The method for calibrating a composite field flow meter according to claim 1, characterized in that: in In step S6, the standard instrument can be removed from the clamping device to perform separate verification measurements of the volumetric measuring device.

3. The method for calibrating a composite field flow meter according to claim 1, characterized in that: in In step S7, the standard instrument can be removed from the clamping device to perform separate calibration measurements on the weight-type measuring device.

4. The method for calibrating a composite field flow meter according to claim 1, characterized in that: The instrument clamping device includes a clamping base, a fixed pipe, an intermediate pipe, and a telescopic pipe. One end of the clamping base has a fixed bracket. The fixed pipe is horizontally fixed to the upper end of the fixed bracket, with its outer end connected to the first circulation pipeline. The inner end of the fixed pipe is coaxially fitted with a clamping connector. A guide rail is located in the middle of the clamping base, and several intermediate brackets are slidably connected to the middle of the guide rail via a slider. An intermediate pipe is horizontally fixed to the upper end of the intermediate bracket, with clamping connectors coaxially fitted at both ends. The other end of the clamping base has a clamping bracket slidably connected to the guide rail via a slider. A telescopic drive device is located at the upper end of the clamping bracket, and a telescopic pipe is installed inside the telescopic drive device. The outer end of the telescopic pipe is connected to the second circulation pipeline via a flexible metal hose, and the inner end of the telescopic pipe is coaxially fitted with a clamping connector. The fixed pipe, several intermediate pipes, and the telescopic pipe are all coaxially corresponding. The upper surface of the clamping base has a positioning rack extending to both ends of the clamping base along the length direction. A check plate is hinged to the upper part of the outer side of the clamping bracket, and the lower end of the check plate is inserted into the right-angle tooth groove of the positioning rack.

5. The method for calibrating a composite field flow meter according to claim 4, characterized in that: The telescopic drive device includes an annular turbine and a worm gear installed inside the housing support and meshing with each other, and a telescopic tube with external threads on its outer side. The housing support is fixed to the upper end of the clamping bracket. Hollow shafts are coaxially fixedly connected to both ends of the annular turbine. The two hollow shafts are rotatably connected to the side walls at both ends of the housing support through bearings. An internal thread is provided in the middle hole of the annular turbine. The telescopic tube passes through the hollow shaft and is sleeved in the middle hole of the annular turbine, and the external thread of the telescopic tube meshes with the internal thread of the middle hole. A motor is provided at the upper end of the housing support. The drive shaft of the motor and the shaft of the worm gear are coaxially fixedly connected.

6. The method for calibrating a composite field flow meter according to claim 1, characterized in that: The volumetric measuring device includes a volumetric piston cylinder and a conical pneumatic directional valve. The conical pneumatic directional valve includes a cylinder, two identical valve bodies A, and two identical valve bodies B. The two valve bodies A are coaxially and symmetrically sealed to the two ends of the cylinder. A cylindrical cavity A is coaxially provided inward from the center of the outer end face of the valve body A. A shaft hole A is provided at the center of the inner end face of the cylindrical cavity A. The side wall of the valve body A is provided with an inlet and outlet that communicates with the middle of the cylindrical cavity A along the radial direction. The inlet and outlet on one side of the valve body A is designated as the first valve body inlet and outlet, and the inlet and outlet on the other side of the valve body A is designated as the second valve body inlet and outlet. Two valve bodies B are coaxially and symmetrically sealed and connected to the outer ends of two valve bodies A. A valve core cavity is provided axially inward from the center of the inner side surface of valve body B. An inlet and outlet communicating with the center of the valve core cavity are provided radially on the side wall of valve body B. One inlet and outlet is a drain port and the other inlet and outlet is an inlet. A cylindrical cavity B is coaxially provided at the center of the inner end face of the valve core cavity. An inlet and outlet communicating with the center of the cylindrical cavity B are provided radially on the side wall of valve body B. The inlet and outlet on one side of valve body B is a third valve body inlet and outlet, and the inlet and outlet on the other side of valve body B is a fourth valve body inlet and outlet. A shaft hole B is provided at the center of the inner end face of the cylindrical cavity B. The valve core includes two identical valve core components, which are symmetrically installed on both sides inside the valve body. Each valve core component includes two symmetrically arranged and spaced conical valves. The two conical valves are coaxially and fixedly connected as one unit by a valve core shaft. The inner end of the valve core shaft passes through shaft hole B and extends into the cylinder, and is fixedly connected to the center of the piston body inside the cylinder. The outer end of the valve core shaft exits from shaft hole B. The conical valves are located inside the valve core cavity, and the tips of the conical valves face cylindrical cavity A or cylindrical cavity B. A circular baffle is coaxially provided on the end face of the conical valve, and the diameter of the circular baffle is larger than the diameter of cylindrical cavity B. A volumetric piston cylinder includes a cylinder body, end caps coaxially fixedly connected at both ends of the cylinder body, and a piston installed inside the cylinder body. The inner end face of the end cap has a frustum-shaped reduction groove along the axial direction. The bottom center of the frustum-shaped reduction groove has a sliding hole that passes through the end cap. One end side wall of the cylinder body has two cylinder inlets and outlets, namely the first cylinder inlet and outlet and the second cylinder inlet and outlet. The other end side wall has two cylinder inlets and outlets along the radial direction, namely the third cylinder inlet and outlet and the fourth cylinder inlet and outlet. Two piston rods are symmetrically arranged along the axial direction at the center of both end faces of the piston. The outer ends of the two piston rods extend from the sliding holes at both ends of the cylinder body respectively. The inner ends of the piston rods are coaxially fixedly connected to a circular reduction disk. There is a gap between the reduction disk and the piston disk. The inlet and outlet of the first valve body and the inlet and outlet of the third cylinder body are connected by pipe A; the inlet and outlet of the second valve body and the inlet and outlet of the fourth cylinder body are connected by pipe B; the inlet and outlet of the third valve body and the inlet and outlet of the first cylinder body are connected by pipe C; the inlet and outlet of the fourth valve body and the inlet and outlet of the second cylinder body are connected by pipe D; the liquid inlet is connected to the second circulation pipe; and the liquid outlet is connected to the oil tank through the liquid outlet pipe.

7. The method for calibrating a composite field flow meter according to claim 6, characterized in that: The cylinder body has several axial thermostatic holes evenly distributed in the side wall. The two ends of the thermostatic holes pass through the two end faces of the cylinder body. An annular pad is coaxially fixed between the end cover and the cylinder body. The annular pad has an annular groove coaxially provided in the middle of the inner end face to cover the port of the thermostatic hole. An annular cavity is formed between the annular groove and the end face of the cylinder body. The side of the annular pad at one end of the cylinder body has a thermostatic oil inlet and outlet that pass through the annular groove. The side of the annular pad at the other end of the cylinder body has a thermostatic oil inlet and outlet that pass through the annular groove.

8. The method for calibrating a composite field flow meter according to claim 1, characterized in that: The weight-type measuring device includes a commutator and identical weighing devices A and B. The middle of one end of the commutator is connected to the circulation branch B. The commutator is connected to two outlet pipes for switching liquid discharge, designated as outlet pipe A and outlet pipe B. Weighing device A includes a weighing instrument A and a weighing box A placed on the weighing instrument A via a bracket. The bottom of the weighing box A is provided with an outlet pipe A that connects to the oil tank. A pneumatic valve A is provided on the outlet pipe A. The weighing box A is located directly below the outlet pipe A. The components of the weighing device are designated as weighing box B, weighing instrument B, outlet pipe B, and pneumatic valve B. Weighing box B is located directly below the outlet pipe B.

9. The method for calibrating a composite field flow meter according to claim 8, characterized in that: The specific measurement method of the weight-type measuring device in S7 is as follows: the oil enters the weighing box A from the outlet pipe A through the reversing device. At this time, the weighing instrument A is working and the pneumatic valve A is closed. After the oil in the weighing box A is collected to the set value of the weighing instrument A, the reversing device switches the oil to the outlet pipe B. The oil enters the weighing box B from the outlet pipe B. At this time, the weighing instrument B is working and the pneumatic valve B is closed. During the switching process, the weighing box A and the weighing instrument A tend to stabilize. The weighing weight of the weighing instrument A is read. Then, the pneumatic valve A is opened to quickly empty the oil and then closed. The weighing instrument A is zeroed. The weighing device B weighs and zeroes according to the steps of the weighing device A, and continuously weighs the oil.

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