A calibration device and method for a variable head water flow standard device

Abstract

The present invention belongs to the technical field of flow calibration, and discloses a calibration device for a variable head water flow standard device, including a pressure-stabilizing water tower, the pressure-stabilizing water tower is connected with a standard flow meter, a water pump, a water weighing device and a water tank, and a variable head water flow standard device to be calibrated through a water direction regulating module, the water direction regulating module, the standard flow meter, the water weighing device, and the variable head water flow standard device to be calibrated are all connected with a processor, and the processor controls the flow direction of liquid water between the pressure-stabilizing water tower, the standard flow meter, the water pump, the water weighing device and the water tank, and the variable head water flow standard device to be calibrated through the water direction regulating module, first completes the calculation of the instrument coefficient or flow correction value of the standard flow meter, and then completes the volume calculation of each volume section of the volume section water tower in the variable head water flow standard device to be calibrated, thereby realizing automatic calibration of the variable head water flow standard device to be calibrated. A calibration method for a variable head water flow standard device is also disclosed.

Description

Technical Field

[0001] The invention belongs to the technical field of flow calibration, and in particular relates to a calibration device and method for a variable head water flow standard device. Background Art

[0002] At present, large-caliber liquid flow meters are responsible for the flow measurement tasks of enterprise production water, urban domestic water, and sewage discharge. According to the current national calibration regulations, the static volume method or static mass method is generally used to calibrate liquid flow meters. The water flow standard device based on these methods requires a stable pressure source, which is generally achieved using a high-level water tower or a pressure-stabilizing container. In the calibration process, in order to maintain constant pressure, the high-level water tower must maintain a continuous overflow state of water supply, which consumes a lot of energy and has low device efficiency. Therefore, many domestic and foreign companies have manufactured dynamic volumetric water flow standard devices based on the variable head principle, using a volumetric segment water tower with several liquid level gauges on the water tower. The volume between every two liquid level gauges is a standard volume segment. When the variable head water flow standard device is working, as the water level in the water tower drops, the flow rate will also drop. By continuously increasing the opening of the flow regulating valve, the flow rate can be kept basically constant. The variable head water flow standard device has obvious advantages in reducing energy consumption and effectively utilizing water resources. In order to ensure the accuracy of the variable head water flow standard device, the measurement of the device is a key technology, and there is currently no device or method that can perform comprehensive measurement for this. Summary of the invention

[0003] The present invention provides a calibration device and method for a variable head water flow standard device, which fills the domestic calibration gap for variable head water flow standard devices and provides metrological technical guarantee for the traceability of the value of products such as large-caliber liquid flow meters.

[0004] The present invention can be achieved through the following technical solutions:

[0005] A calibration device for a variable head water flow standard device, comprising a pressure-stabilizing water tower, wherein the pressure-stabilizing water tower is connected to a standard flow meter, a water pump, a water weighing device and a water tank, as well as a variable head water flow standard device to be calibrated through a water direction regulating module, wherein the water direction regulating module, the standard flow meter, the water weighing device and the variable head water flow standard device to be calibrated are all connected to a processor, wherein the processor controls the flow direction of liquid water among the pressure-stabilizing water tower, the standard flow meter, the water pump, the water weighing device and the water tank, as well as the variable head water flow standard device to be calibrated through the water direction regulating module, firstly calculates the instrument coefficient or flow correction value of the standard flow meter, and then calculates the volume of each volume section of the volume section water tower in the variable head water flow standard device to be calibrated, thereby realizing automatic calibration of the variable head water flow standard device to be calibrated.

[0006] Furthermore, the processor first controls the flow direction of liquid water between the pressure-stabilizing water tower, standard flow meter, water pump, water weighing device and water pool through the water direction regulation module, and then controls the flow direction of liquid water between the standard flow meter, water pool and the calibrated head water flow standard device.

[0007] Furthermore, the water direction regulating module includes a flow regulating valve, which is connected to the pressure-stabilizing water tower through a standard flow meter and a first solenoid valve in sequence, connected to the water pool through a second solenoid valve, connected to a water volume weighing device and a water pool through a reversing device, the water volume weighing device is connected to the water pool through a third solenoid valve, the water pool is connected to the pressure-stabilizing water tower through a water pump and a fourth solenoid valve, and the standard flow meter is connected to the calibrated head water flow standard device through a fifth solenoid valve.

[0008] Furthermore, the calibrated head water flow standard device includes a volumetric water tower, and each liquid level gauge on the volumetric water tower is connected to the processor, which is connected to the first water tank through the sixth solenoid valve, and is also connected to the first water tank through the seventh solenoid valve and the first water pump, and is connected to the standard flow meter through the fifth solenoid valve.

[0009] Furthermore, the water weighing device comprises an electronic scale, and a container for holding water is arranged on the electronic scale.

[0010] A calibration method for a calibration device for a variable head water flow standard device based on the above-mentioned method, which controls a water direction regulating module to close the connection with the variable head water flow standard device to be calibrated, first completes the calculation of the instrument coefficient of the standard flow meter, and then opens the connection with the variable head water flow standard device to be calibrated, completes the volume calculation of each volume section of the volume section water tower in the variable head water flow standard device to be calibrated, thereby realizing the calibration of the variable head water flow standard device to be calibrated.

[0011] Further, the calculation of the instrument coefficient for the standard flow meter includes the following steps:

[0012] Step 1: Close the fifth solenoid valve and the second solenoid valve, turn the commutator to the position of flowing to the pool, open the fourth solenoid valve and the water pump, and fill the pressure-stabilizing water tower with water until there is overflow in its overflow pipe;

[0013] Step 2: Open the third solenoid valve to drain the water in the container into the pool until the reading on the electronic scale is zero;

[0014] Step 3: Open the first solenoid valve and adjust the flow control valve to make the flow through the standard flow meter reach the set value;

[0015] Step 4: Close the third solenoid valve, turn the commutator to the water weighing device position, start counting the pulses of the standard flow meter, stop counting the pulses of the standard flow meter after a predetermined time, and turn the commutator to the flow to the pool position, read the indication m of the electronic scale and the pulse accumulation value N of the standard flow meter;

[0016] Step 5. Calculate the volume V of the corresponding water according to the indication m of the electronic scale, and then use the following equation to calculate the instrument factor K of the standard flow meter used in this measurement;

[0017] K=N / V

[0018] Step 6: Repeat steps 2 to 5 to obtain multiple groups of instrument coefficients K and calculate their average value Km.

[0019] Furthermore, completing the volume calculation of each volume section of the volume section water tower in the calibrated variable head and water flow standard device includes the following steps:

[0020] Step I: close the first solenoid valve, the fourth solenoid valve and the water pump to stop the pressure-stabilizing water tower from working;

[0021] Step II, close the sixth solenoid valve, open the seventh solenoid valve and the first water pump, fill water into the volume section water tower until the water level exceeds the first liquid level gauge thereon, and close the first water pump;

[0022] Step III, opening the fifth solenoid valve and the second solenoid valve, and adjusting the flow regulating valve so that the flow rate flowing through the standard flow meter reaches the set value;

[0023] Step IV, when the water level of the volume section water tower drops to the first liquid level meter, start counting the pulse number of the standard flow meter; when the water level drops to the second liquid level meter, record the cumulative pulse number N1 of the standard flow meter corresponding to the period from the first liquid level meter to the second liquid level meter; when the water level drops to the third liquid level meter, record the cumulative pulse number N2 of the standard flow meter corresponding to the period from the second liquid level meter to the third liquid level meter; when the water level drops to the fourth liquid level meter, record the cumulative pulse number N3 of the standard flow meter corresponding to the period from the third liquid level meter to the fourth liquid level meter; and so on, to obtain the cumulative pulse number Nm of the standard flow meter corresponding to each volume section.

[0024] Step V: Calculate the volume Vm of each volume segment using the equation Vm=Nm / Km.

[0025] Step VI, repeat steps II to V to obtain multiple groups of volume values, calculate their corresponding average values, thereby obtaining the volume of each volume segment of the volume segment water tower, and set the volume of each volume segment to the variable head water flow standard device for calibration of the calibrated flow meter.

[0026] The beneficial technical effects of the present invention are:

[0027] The water direction regulating module is used to control the flow direction of liquid water between the pressure-stabilizing water tower, standard flow meter, water pump, water weighing device and water pool as well as the calibrated variable head water flow standard device. The instrument coefficient of the standard flow meter is calculated first, and then the volume calculation of each volume section of the volume section water tower in the calibrated variable head water flow standard device is completed, thereby realizing automatic calibration of the calibrated variable head water flow standard device, improving the measurement accuracy of the variable head water flow standard device, providing metrological technical guarantee for the traceability of the measurement value of products such as large-caliber liquid flow meters, and having an important impact on the effective development and utilization of energy in society and the effective implementation of energy conservation and emission reduction goals by industrial enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structural connection of the calibration device of the present invention;

[0029] Among them, 1-pressure stabilizing water tower, 2-standard flow meter, 3-water pump, 4-water tank, 5-volume section water tower, 6-flow regulating valve, 7-commutator, 8-first water tank, 9-first water pump, 10-electronic scale, 11-container, 12-flat device. DETAILED DESCRIPTION

[0030] The specific implementation of the present invention is described in detail below with reference to the accompanying drawings and preferred embodiments.

[0031] Compared with the current static mass method and static volume method liquid flow standard devices, the dynamic volumetric method water flow standard device based on the variable head principle has obvious advantages in reducing energy consumption and effectively utilizing water resources. It is particularly suitable for the calibration of large-caliber flow meters. More and more flow meter manufacturers adopt this method, so the calibration of the standard device has become more and more urgent. The present invention provides a calibration device for a variable head water flow standard device, including a pressure-stabilizing water tower 1, which is connected to a standard flow meter 2, a water pump 3, a water weighing device and a water tank 4 through a water direction regulating module, and a variable head to be calibrated. The water flow standard device is connected, and the water direction regulating module, the standard flow meter 2, the water weighing device, and the calibrated water head water flow standard device are all connected to the processor. The processor controls the flow direction of liquid water between the pressure-stabilizing water tower 1, the standard flow meter 2, the water pump 3, the water weighing device and the water tank 4, as well as the calibrated water head water flow standard device through the water direction regulating module. The instrument coefficient or flow correction value of the standard flow meter 2 is calculated first, and then the volume calculation of each volume section of the volume section water tower 5 in the calibrated water head water flow standard device is completed, thereby realizing automatic calibration of the calibrated water head water flow standard device.

[0032] Specifically, the processor first controls the flow direction of liquid water between the pressure-stabilizing water tower 1, the standard flow meter 2, the water pump 3, the water quantity weighing device and the water pool 4 through the water direction regulation module, and then controls the flow direction of liquid water between the standard flow meter 2, the water pool 4 and the calibrated head water flow standard device.

[0033] The water direction regulating module includes a flow regulating valve 6, which is connected to the pressure-stabilizing water tower 1 through the standard flow meter 2 and the first solenoid valve in sequence, connected to the water pool 4 through the second solenoid valve, and connected to the water weighing device and the water pool 4 through the commutator 7. The water weighing device is connected to the water pool 4 through the third solenoid valve, and the water pool 4 is connected to the pressure-stabilizing water tower 1 through the water pump 3 and the fourth solenoid valve. The standard flow meter 2 is connected to the calibrated variable head water flow standard device through the fifth solenoid valve. The calibrated variable head water flow standard device includes a volumetric section water tower 5, and each level gauge on the volumetric section water tower 5 is connected to the processor, which is connected to the first water pool 8 through the sixth solenoid valve, and is also connected to the first water pool 8 through the seventh solenoid valve and the first water pump 9, and is connected to the standard flow meter 2 through the fifth solenoid valve.

[0034] Among them, the pressure-stabilizing water tower 1 includes a high-level water tower or a pressure-stabilizing container, which is used to provide a stable pressure source to maintain a non-time-varying steady flow in the pipeline; each solenoid valve can be a butterfly valve, a ball valve or other valves of different principles, which are used to control the opening or closing of pipelines in the entire calibration device, and the flow regulating valve 6 is used to adjust the instantaneous flow through the standard flow meter 2; the standard flow meter 2 is used as a transfer standard, and an electromagnetic flow meter with a repeatability better than 0.02% is generally selected; the water weighing device includes an electronic scale 10, on which a water container 11 is arranged, the container 11 is used to hold water flowing through the standard flow meter 2, and then weigh it through an electronic scale 9 to calculate the corresponding water volume; and the water pool is used to store water to realize water circulation, the water pump 3 draws water into the pressure-stabilizing water tower, and the water in the container or pipeline can also be discharged into the water pool.

[0035] The processor can be implemented through a flat panel device 12 to monitor the calibration device of the entire variable head water flow standard device, including controlling the valve opening, controlling the operation of the water pump 3, controlling the operation of the standard flow meter 2, controlling the switching direction of the commutator 7, displaying the reading of the electronic scale 9 and converting it into the volume of water, displaying the pulse coefficient of the standard flow meter 2, storing calibration data, etc.

[0036] The present invention also provides a calibration method for the calibration device for the variable head water flow standard device described above, by controlling the water direction regulating module to close the connection with the variable head water flow standard device to be calibrated, first completing the instrument coefficient calculation of the standard flow meter, and then opening the connection with the variable head water flow standard device to be calibrated, completing the volume calculation of each volume section of the volume section water tower in the variable head water flow standard device to be calibrated, thereby realizing the calibration of the variable head water flow standard device to be calibrated.

[0037] The calculation of the instrument coefficient of the standard flow meter includes the following steps:

[0038] Step 1: Close the fifth solenoid valve and the second solenoid valve, turn the commutator to the position of flowing to the pool, open the fourth solenoid valve and the water pump, and fill the pressure-stabilizing water tower with water until there is overflow in its overflow pipe;

[0039] Step 2: Open the third solenoid valve to drain the water in the container into the pool until the reading on the electronic scale is zero;

[0040] Step 3: Open the first solenoid valve and adjust the flow control valve to make the flow through the standard flow meter reach the set value. Generally, the flow point with the best repeatability of the standard meter is used, such as 50% of the full scale.

[0041] Step 4: Close the third solenoid valve, turn the commutator to the water weighing device position, start counting the pulses of the standard flow meter, and stop counting the pulses of the standard flow meter after a predetermined time, such as 60 seconds. At the same time, turn the commutator to the flow to the pool position, and read the indication m of the electronic scale and the pulse accumulation value N of the standard flow meter.

[0042] Step 5. Calculate the volume V of the corresponding water according to the indication m of the electronic scale, and then use the following equation to calculate the instrument factor K of the standard flow meter used in this measurement;

[0043] K=N / V

[0044] Step 6: Repeat steps 2 to 5 to obtain multiple groups of instrument coefficients K, such as six groups, and calculate their average value Km.

[0045] If the standard flow meter does not use the instrument coefficient, the standard flow meter is turned on and the flow value is counted. After a preset time, such as 60 seconds, the cumulative calculation of the flow value is stopped, and the commutator is switched to the flow direction of the pool. The value of the electronic scale at this time, that is, the mass m of the water, is read. After corrections for water temperature, water density and air buoyancy, the volume V of the water is obtained. At the same time, the cumulative flow value Vc of the standard flow meter is read, and the equation σ=V / Vc is used to calculate the flow correction value σ of the standard meter measured this time. Similarly, the above process is repeated multiple times to calculate the average value σ m .

[0046] The following steps are included to complete the volume calculation of each volume section of the volume section water tower in the calibrated variable head and water flow standard device:

[0047] Step I: close the first solenoid valve, the fourth solenoid valve and the water pump to stop the pressure-stabilizing water tower from working;

[0048] Step II, close the sixth solenoid valve, open the seventh solenoid valve and the first water pump, fill water into the volume section water tower until the water level exceeds the first liquid level gauge thereon, and close the first water pump;

[0049] Step III, opening the fifth solenoid valve and the second solenoid valve, and adjusting the flow regulating valve so that the flow rate flowing through the standard flow meter reaches the set value;

[0050] Step IV, when the water level of the volume section water tower drops to the first liquid level meter, start counting the pulse number of the standard flow meter; when the water level drops to the second liquid level meter, record the cumulative pulse number N1 of the standard flow meter corresponding to the period from the first liquid level meter to the second liquid level meter; when the water level drops to the third liquid level meter, record the cumulative pulse number N2 of the standard flow meter corresponding to the period from the second liquid level meter to the third liquid level meter; when the water level drops to the fourth liquid level meter, record the cumulative pulse number N3 of the standard flow meter corresponding to the period from the third liquid level meter to the fourth liquid level meter; and so on, to obtain the cumulative pulse number Nm of the standard flow meter corresponding to each volume section.

[0051] Step V: Calculate the volume Vm of each volume segment using the equation Vm=Nm / Km.

[0052] Similarly, if the standard flow meter does not use the instrument coefficient, the flow accumulated values ​​Vc1, Vc2…Vcm… are recorded in step IV, and the volume of each volume segment Vm=Vcm*σ in step V m .

[0053] Step VI, repeat steps II to V to obtain multiple groups of volume values, calculate their corresponding average values, thereby obtaining the volume of each volume segment of the volume segment water tower, and set the volume of each volume segment to the variable head water flow standard device for calibration of the calibrated flow meter.

[0054] During the whole calibration process, some uncertainty components will be introduced, such as tower thermal expansion coefficient, liquid temperature, electronic scale, volume calibration repeatability, commutator, dynamic effect of each level meter, standard flow meter repeatability, etc. By analyzing and synthesizing these uncertainties, the expanded uncertainty of the variable head water flow standard device can be obtained, such as 0.06% (k = 2), then the device can be used to calibrate a large-caliber liquid flow meter of level 0.2.

[0055] Although specific embodiments of the present invention are described above, those skilled in the art should understand that these are merely examples and that various changes or modifications may be made to these embodiments without departing from the principles and essence of the present invention. Therefore, the scope of protection of the present invention is limited by the appended claims.

Claims

1. A calibration method for a calibration device of a variable head water flow standard device, characterized in that: The calibration device includes a pressure-stabilizing water tower, which is connected to a standard flow meter, a water pump, a water weighing device and a water tank, as well as a standard device for calibrated water head and flow rate through a water direction regulating module. The water direction regulating module, the standard flow meter, the water weighing device and the standard device for calibrated water head and flow rate are all connected to a processor. The processor controls the flow direction of liquid water between the pressure-stabilizing water tower, the standard flow meter, the water pump, the water weighing device and the water tank, as well as the standard device for calibrated water head and flow rate through the water direction regulating module, first completes the calculation of the instrument coefficient or flow correction value of the standard flow meter, and then completes the volume calculation of each volume section of the volume section water tower in the standard device for calibrated water head and flow rate, thereby realizing the calibration of the standard device for calibrated water head and flow rate; The processor first controls the flow direction of liquid water between the pressure-stabilizing water tower, the standard flow meter, the water pump, the water weighing device and the water pool through the water direction regulating module, and then controls the flow direction of liquid water between the standard flow meter, the water pool and the calibrated head water flow standard device; The water direction regulating module includes a flow regulating valve, which is connected to a pressure-stabilizing water tower through a standard flow meter and a first solenoid valve in sequence, connected to a water pool through a second solenoid valve, connected to a water weighing device and a water pool through a commutator, the water weighing device is connected to the water pool through a third solenoid valve, the water pool is connected to a pressure-stabilizing water tower through a water pump and a fourth solenoid valve, and the standard flow meter is connected to a calibrated water head water flow standard device through a fifth solenoid valve; The calibrated water head and water flow standard device comprises a volumetric water tower, each level gauge on the volumetric water tower is connected to the processor, which is connected to the first water tank through the sixth solenoid valve, is also connected to the first water tank through the seventh solenoid valve and the first water pump, and is connected to the standard flow meter through the fifth solenoid valve; The calibration method controls the water direction regulating module to close the connection with the calibrated variable head water flow standard device, first completes the instrument coefficient calculation of the standard flow meter, and then opens the connection with the calibrated variable head water flow standard device to complete the volume calculation of each volume section of the volume section water tower in the calibrated variable head water flow standard device, thereby realizing the calibration of the calibrated variable head water flow standard device; The following steps are required to calculate the instrument factor for a standard flow meter: Step 1: Close the fifth solenoid valve and the second solenoid valve, turn the commutator to the position of flowing to the pool, open the fourth solenoid valve and the water pump, and fill the pressure-stabilizing water tower with water until there is overflow in its overflow pipe; Step 2: Open the third solenoid valve to drain the water in the container into the pool until the reading on the electronic scale is zero; Step 3: Open the first solenoid valve and adjust the flow control valve to make the flow through the standard flow meter reach the set value; Step 4: Close the third solenoid valve, turn the commutator to the water weighing device position, start counting the pulses of the standard flow meter, stop counting the pulses of the standard flow meter after a predetermined time, and turn the commutator to the flow to the pool position, read the indication m of the electronic scale and the pulse accumulation value N of the standard flow meter; Step 5. Calculate the volume V of the corresponding water according to the indication m of the electronic scale, and then use the following equation to calculate the instrument factor K of the standard flow meter used in this measurement; K=N / V Step 6: Repeat steps 2 to 5 to obtain multiple groups of instrument coefficients K, and calculate their average value Km; The following steps are included to complete the volume calculation of each volume section of the volume section water tower in the calibrated variable head and water flow standard device: Step I: close the first solenoid valve, the fourth solenoid valve and the water pump to stop the pressure-stabilizing water tower from working; Step II, close the sixth solenoid valve, open the seventh solenoid valve and the first water pump, fill water into the volume section water tower until the water level exceeds the first liquid level gauge thereon, and close the first water pump; Step III, opening the fifth solenoid valve and the second solenoid valve, and adjusting the flow regulating valve so that the flow rate flowing through the standard flow meter reaches the set value; Step IV, when the water level of the water tower in the volume section drops to the first liquid level meter, start counting the pulse number of the standard flow meter, when the water level drops to the second liquid level meter, record the cumulative pulse number N1 of the standard flow meter corresponding to the period from the first liquid level meter to the second liquid level meter, when the water level drops to the third liquid level meter, record the cumulative pulse number N2 of the standard flow meter corresponding to the period from the second liquid level meter to the third liquid level meter, when the water level drops to the fourth liquid level meter, record the cumulative pulse number N3 of the standard flow meter corresponding to the period from the third liquid level meter to the fourth liquid level meter, and so on, to obtain the cumulative pulse number Nm of the standard flow meter corresponding to each volume section; Step V, using the equation Vm=Nm / Km, calculate the volume Vm of each volume segment; Step VI, repeat steps II to V to obtain multiple groups of volume values, calculate the corresponding average values, thereby obtaining the volume of each volume segment of the volume segment water tower, and set the volume of each volume segment to the variable head water flow standard device for calibration of the calibrated flow meter.

2. The calibration method for the calibration device of the variable head water flow standard device according to claim 1, characterized in that: The water weighing device comprises an electronic scale, and a container for holding water is arranged on the electronic scale.

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