CN111337111A - A calibration device and method for a variable head water flow standard device - Google Patents

Abstract

The invention belongs to the technical field of flow calibration, and discloses a calibration device for a variable water head water flow standard device, which comprises a pressure stabilizing water tower, the pressure stabilizing water tower is connected with a standard flowmeter, a water pump, a water quantity weigher and a water tank through a water direction adjusting module, the water direction adjusting module, the standard flowmeter, the water quantity weigher and the calibrated variable head water flow standard device are all connected with the processor, the processor controls liquid water in a pressure stabilizing water tower, a standard flowmeter, a water pump, a water quantity weigher and a water tank through a water direction adjusting module, and the flow direction between the corrected variable head water flow standard devices, firstly completing the calculation of the instrument coefficient or the flow correction value of the standard flowmeter, and then completing the volume calculation of each volume section of the volume section water tower in the corrected variable head water flow standard devices, thereby realizing the automatic calibration of the corrected variable head water flow standard devices. A calibration method for the variable head water flow rate calibration device is also disclosed.

Description

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

technical field

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 technique

At present, large-diameter 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 verification regulations, the static volume method or the static mass method is generally used to verify the liquid flowmeter. The water flow standard device based on these methods requires a stable pressure source, which is generally realized by a high-level water tower or a pressure-stabilizing container. To maintain constant pressure, the high-level water tower must maintain the overflowing state of continuous water supply. The energy consumption is large and the device efficiency is low. Therefore, many domestic and foreign companies have manufactured dynamic volumetric water flow standard devices based on the principle of variable water head. There are several level gauges, and the volume between each two 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 control valve, the flow rate is basically kept constant. The variable head water flow standard device can reduce energy consumption and reduce energy consumption. The effective utilization of water resources has obvious advantages. 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 comprehensively measure this.

SUMMARY OF THE INVENTION

The invention provides a calibration device and method for a variable head water flow standard device, which makes up the domestic calibration blank for the variable head water flow standard device, and provides a measurement technical guarantee for the traceability of large-diameter liquid flow meters and other products. .

The present invention can be realized through the following technical solutions:

A calibration device for a standard device for variable head water flow, comprising a stabilized water tower, the stabilized water tower communicates with a standard flowmeter, a water pump, a water weigher and a pool through a water direction adjustment module, and the water flow rate of the corrected head The standard device is connected, and the water direction adjustment module, the standard flow meter, the water volume weighing device, and the corrected head water flow standard device are all connected with the processor, and the processor controls the liquid water in the stabilized water tower through the water direction adjustment module. , standard flowmeter, water pump, water weighing device and pool, as well as the flow direction between the calibrated head water flow standard device, first complete the calculation of the meter coefficient or flow correction value of the standard flowmeter, and then complete the calibrated water head. Calculate the volume of each volume section of the water tower in the volume section of the water flow standard device, so as to realize the automatic calibration of the corrected head water flow standard device.

Further, the processor first controls the flow direction of liquid water between the stabilized water tower, the standard flowmeter, the water pump, the water scale and the pool through the water direction adjustment module, and then controls the flow of liquid water between the standard flowmeter, the pool and the calibrated water tank. The flow direction between the variable head water flow standard devices.

Further, the water direction regulating module includes a flow regulating valve, the flow regulating valve is communicated with the stabilized water tower through a standard flow meter and the first solenoid valve in turn, communicated with the water pool through the second solenoid valve, and communicated with the water scale through the commutator. The weighing device and the pool are communicated, the water weighing device is communicated with the pool through the third solenoid valve, the pool is communicated with the pressure-stabilizing water tower through the water pump and the fourth solenoid valve, and the standard flowmeter is communicated with the calibrated water tower through the fifth solenoid valve. The variable head water flow standard device is connected.

Further, the corrected head water flow standard device includes a volume section water tower, and each liquid level gauge on the volume section water tower is connected to the processor, which is communicated with the first pool through the sixth solenoid valve, and the seventh solenoid valve is used. The valve and the first water pump are also communicated with the first pool, and communicated with the standard flow meter through the fifth solenoid valve.

Further, the water weighing device includes an electronic scale, and the electronic scale is provided with a container for holding water.

A calibration method based on the calibration device for the variable head water flow standard device described above, by controlling the water direction adjustment module to close the communication with the corrected head water flow standard device, first complete the calibration of the standard flowmeter. Calculate the coefficient of the meter, and then open the connection with the corrected head water flow standard device to complete the volume calculation of each volume section of the water tower in the volume section of the corrected head water flow standard device, so as to realize the corrected head water flow rate. Calibration of flow standard devices.

Further, completing the calculation of the meter coefficient for the standard flowmeter includes the following steps:

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 inject water into the stabilized water tower until the overflow pipe overflows;

Step 2: Open the third solenoid valve, and discharge the water in the container into the pool until the indication of the electronic scale is zero;

Step 3: Open the first solenoid valve, and adjust the flow regulating 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 position of the water scale, and start counting the pulses of the standard flowmeter. After a predetermined time, stop counting the pulses of the standard flowmeter, and turn the commutator to Go to the flow direction pool position, read the indication m of the electronic scale and the pulse accumulated value N of the standard flow meter at this time;

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 meter coefficient K of the standard flowmeter measured this time;

K=N/V

Step 6: Repeat steps 2 to 5 to obtain multiple sets of meter coefficients K, and calculate their average value Km.

Further, completing the volume calculation of each volume section of the volume section water tower in the corrected head water flow standard device includes the following steps:

Step 1, close the first solenoid valve, the fourth solenoid valve and the water pump, so that the stabilized water tower stops working;

Step II, close the sixth solenoid valve, open the seventh solenoid valve and the first water pump, inject water into the volume section water tower until the water level exceeds the first liquid level gauge on it, and close the first water pump;

Step III: Open the fifth solenoid valve and the second solenoid valve, and adjust the flow regulating valve to make the flow through the standard flow meter reach the set value;

Step IV. When the water level of the volumetric water tower drops to the first liquid level, start counting the pulses of the standard flowmeter. When the water level drops to the second liquid level, record the change from the first liquid level gauge to the second liquid level gauge. This period of time corresponds to the cumulative pulse number N1 of the standard flowmeter. When the water level drops to the third liquid level, record the time from the second liquid level gauge to the third liquid level gauge, which corresponds to the cumulative pulse number N2 of the standard flowmeter. When the water level drops to the fourth level, record the cumulative pulse number N3 of the standard flowmeter corresponding to the change from the third level gauge to the fourth level gauge, and so on to get the standard flowmeter corresponding to each volume segment The cumulative number of pulses Nm.

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 their corresponding average values, thereby obtain the volume of each volume section of the volume section water tower, and set the volume of each volume section to the variable head water flow standard device, Used for calibration of the flowmeter being calibrated.

The beneficial technical effects of the present invention are:

Control the flow direction of liquid water between the stabilized water tower, the standard flow meter, the water pump, the water weighing device and the pool, and the standard device for the water flow rate of the water head to be corrected through the water direction adjustment module. Then complete the volume calculation of each volume section of the water tower in the volume section of the corrected head water flow standard device, so as to realize the automatic calibration of the corrected head water flow standard device, and improve the measurement accuracy of the variable head water flow standard device. , to provide measurement technical support for the traceability of large-diameter liquid flow meters and other products, which has an important impact on the effective development and utilization of energy in the society and the effective implementation of energy-saving and emission-reduction goals by industrial enterprises.

Description of drawings

Fig. 1 is the structural connection schematic diagram of the calibration device of the present invention;

Among them, 1-stabilizing water tower, 2-standard flowmeter, 3-water pump, 4-water tank, 5-volume section water tower, 6-flow regulating valve, 7-commutator, 8-first pool, 9-first Water pump, 10-electronic scale, 11-container, 12-tablet device.

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

Compared with the current static mass method and static volumetric liquid flow standard device, the dynamic volumetric water flow standard device based on the principle of variable water head has obvious advantages in reducing energy consumption and effective utilization of water resources, and is especially suitable for large-diameter flowmeters. Calibration, more and more flow meter manufacturers use this method, so the calibration of the standard device becomes more and more urgent, the present invention provides a calibration device for a variable head water flow standard device, comprising: The stabilized water tower 1 is communicated with the standard flow meter 2, the water pump 3, the water scale and the pool 4 through the water direction adjustment module, as well as the corrected head water flow standard device. The water direction adjustment module, standard The flowmeter 2, the water weighing device, and the water flow standard device of the corrected head are all connected to the processor. The processor controls the liquid water in the stabilized water tower 1, the standard flowmeter 2, the water pump 3, and the water scale through the water direction adjustment module. The flow direction between the weight device, the pool 4, and the calibrated head water flow standard device, first complete the calculation of the meter coefficient or flow correction value of the standard flow meter 2, and then complete the volume section of the calibrated head water flow standard device. The volume calculation of each volume section of the water tower 5 realizes the automatic calibration of the corrected head water flow standard device.

Specifically, the processor first controls the flow direction of liquid water between the stabilized water tower 1, the standard flow meter 2, the water pump 3, the water weighing device and the pool 4 through the water direction adjustment module, and then controls the flow direction of the liquid water between the standard flow meter 2 , the flow direction between the pool 4 and the water flow standard device of the corrected head.

The water direction regulating module includes a flow regulating valve 6, which in turn communicates with the water stabilizing water tower 1 through the standard flow meter 2 and the first solenoid valve, communicates with the pool 4 through the second solenoid valve, and communicates with the water tank 4 through the commutator 7. The water weighing device and the pool 4 are communicated, the water weighing device is communicated with the pool 4 through the third solenoid valve, the pool 4 is communicated with the stabilized water tower 1 through the water pump 3 and the fourth solenoid valve, and the standard flow meter 2 passes through the fifth solenoid valve. The solenoid valve is communicated with the calibrated water head water flow standard device. The corrected head water flow standard device includes a volume section water tower 5, and each liquid level gauge on the volume section water tower 5 is connected to the processor, which communicates with the first pool 8 through the sixth solenoid valve, and passes through the seventh solenoid valve. , The first water pump 9 is also communicated with the first pool 8, and communicated with the standard flow meter 2 through the fifth solenoid valve.

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 and maintain a time-invariant steady flow in the pipeline; each solenoid valve can be a butterfly valve, a ball valve, etc. It is used to control the opening or closing of the pipelines in the whole calibration device, and the flow control valve 6 is used to adjust the instantaneous flow through the standard flowmeter 2; the standard flowmeter 2 is used as the transmission standard, and the repeatability is generally better than 0.02%. Electromagnetic flowmeter; the water weighing device includes an electronic scale 10 on which a container 11 for holding water is provided, the container 11 is used to hold the water flowing through the standard flowmeter 2, and then weighs it by the electronic scale 9 The water tank is used to store water and realize the circulation of water. The water pump 3 pumps the water into the stabilized water tower, and the water in the container or pipeline can also be discharged into the water tank.

The processor can be implemented by the tablet device 12, and is used 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, and controlling the switching direction of the commutator 7. , display the reading of the electronic scale 9 and convert it into the volume of water, display the pulse coefficient of the standard flow meter 2, store the calibration data and so on.

The present invention also provides a calibration method based on the above-mentioned calibration device for the variable head water flow standard device. By controlling the water direction adjustment module to close the communication with the corrected head water flow standard device, first Complete the calculation of the meter coefficient of the standard flowmeter, then open the connection with the calibrated head water flow standard device, and complete the volume calculation of each volume section of the water tower in the volume section of the calibrated head water flow standard device, so as to realize the Calibration of the calibrated head water flow standard device.

Among them, completing the calculation of the meter coefficient of the standard flowmeter includes the following steps:

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 inject water into the stabilized water tower until the overflow pipe overflows;

Step 2: Open the third solenoid valve, and discharge the water in the container into the pool until the indication of 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. Generally, the flow point with the best repeatability of the standard meter is used, such as 50% of the full scale;

Step 4. Close the third solenoid valve, turn the commutator to the position of the water weighing device, and start counting the pulses of the standard flowmeter. After a predetermined time, such as 60 seconds, stop counting the pulses of the standard flowmeter. Dial the direction device to the position of the flow pool, and read the indication m of the electronic scale and the pulse accumulated value N of the standard flow meter at this time;

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 meter coefficient K of the standard flowmeter measured this time;

K=N/V

Step 6: Repeat steps 2 to 5 to obtain multiple sets of meter coefficients K, such as six sets, and calculate the average value Km.

If the standard flow meter does not use the meter coefficient, start the flow value statistics when the standard flow meter is turned on, stop the cumulative calculation of the flow value after a preset time, such as 60 seconds, and switch the commutator to the pool position. , read the value of the electronic scale at this time, that is, the mass m of water. After the correction of water temperature, water density and air buoyancy, the volume of water V is obtained, and at the same time, the cumulative flow value Vc of the standard flowmeter is read, using the equation σ= V/Vc, calculate the flow correction value σ of the standard meter measured this time, and similarly, repeat the above process several times to calculate the average value σ _m .

Completing the volume calculation of each volume section of the volume section water tower in the corrected head water flow standard device includes the following steps:

Step 1, close the first solenoid valve, the fourth solenoid valve and the water pump, so that the stabilized water tower stops working;

Step II, close the sixth solenoid valve, open the seventh solenoid valve and the first water pump, inject water into the volume section water tower until the water level exceeds the first liquid level gauge on it, and close the first water pump;

Step III: Open the fifth solenoid valve and the second solenoid valve, and adjust the flow regulating valve to make the flow through the standard flow meter reach the set value;

Step IV. When the water level of the volumetric water tower drops to the first liquid level, start counting the pulses of the standard flowmeter. When the water level drops to the second liquid level, record the change from the first liquid level gauge to the second liquid level gauge. This period of time corresponds to the cumulative pulse number N1 of the standard flowmeter. When the water level drops to the third liquid level, record the time from the second liquid level gauge to the third liquid level gauge, which corresponds to the cumulative pulse number N2 of the standard flowmeter. When the water level drops to the fourth level, record the cumulative pulse number N3 of the standard flowmeter corresponding to the change from the third level gauge to the fourth level gauge, and so on to get the standard flowmeter corresponding to each volume segment The cumulative number of pulses Nm.

Step V, using the equation Vm=Nm/Km, calculate the volume Vm of each volume segment.

Likewise, if the standard flow meter does not use the meter coefficient, the accumulated flow value Vc1, Vc2...Vcm... is recorded in step IV, and the volume of each volume segment in step V is Vm=Vcm*σ _m .

Step VI, repeat steps II to V to obtain multiple groups of volume values, calculate their corresponding average values, thereby obtain the volume of each volume section of the volume section water tower, and set the volume of each volume section to the variable head water flow standard device, Used for calibration of the flowmeter being calibrated.

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 gauge, standard flowmeter 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-diameter liquid flowmeter of class 0.2.

Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only examples, and various changes may be made to these embodiments without departing from the principle and essence of the present invention. Modifications, therefore, the scope of protection of the present invention is defined by the appended claims.

Claims (8)

1. A calibrating device for a variable head water flow standard device is characterized in that: the device comprises a pressure stabilizing water tower, wherein the pressure stabilizing water tower is communicated with a standard flowmeter, a water pump, a water quantity weigher and a water tank through a water direction adjusting module, the standard flowmeter, the water quantity weigher and a corrected water head water flow standard device are all connected with a processor, the processor controls the flow direction of liquid water among the pressure stabilizing water tower, the standard flowmeter, the water pump, the water quantity weigher and the water tank and among the corrected water head water flow standard devices through the water direction adjusting module, firstly completes calculation of an instrument coefficient or a flow correction value of the standard flowmeter, and then completes calculation of the volume of each volume section of the water tower in the corrected water head water flow standard device, so that the corrected water head water flow standard device is calibrated.

2. The calibration device for a variable head water flow rate standard device according to claim 1, wherein: the processor controls the flow direction of liquid water among the pressure stabilizing water tower, the standard flowmeter, the water pump, the water quantity weigher and the water tank through the water direction adjusting module, and then controls the flow direction of the liquid water among the standard flowmeter, the water tank and the corrected water head water flow standard device.

3. The calibration device for a variable head water flow rate standard device according to claim 2, wherein: the water is to adjusting module includes flow control valve, flow control valve loops through standard flowmeter, first solenoid valve and steady voltage water tower intercommunication, through second solenoid valve and pond intercommunication, through commutator and water yield weighing device, pond intercommunication, the water yield weighing device passes through third solenoid valve and pond intercommunication, the pond passes through water pump, fourth solenoid valve and steady voltage water tower intercommunication, the standard flowmeter passes through the fifth solenoid valve and is linked together by school variable head water flow standard device.

4. The calibration device for a variable head water flow rate standard device according to claim 3, wherein: the calibrated variable water head water flow standard device comprises a volume section water tower, wherein each liquid level meter on the volume section water tower is connected with a processor, is communicated with a first water tank through a sixth electromagnetic valve, is also communicated with the first water tank through a seventh electromagnetic valve and a first water pump, and is communicated with a standard flow meter through a fifth electromagnetic valve.

5. The calibration device for a variable head water flow rate standard device according to claim 1, wherein: the water quantity weighing device comprises an electronic scale, and a container for containing water is arranged on the electronic scale.

6. A calibration method for a calibration device for a variable head water flow rate standard device according to claim 1, characterized in that: the communication between the standard device and the corrected variable head water flow standard device is closed by controlling the water direction adjusting module, the calculation of the instrument coefficient of the standard flowmeter is completed firstly, then the communication between the standard device and the corrected variable head water flow standard device is opened, the volume calculation of each volume section of the volume section water tower in the corrected variable head water flow standard device is completed, and therefore the correction of the corrected variable head water flow standard device is achieved.

7. The calibration method for a variable head water flow rate calibration device according to claim 6, wherein the step of performing the meter coefficient calculation for the standard flowmeter comprises the steps of:

step one, closing a fifth electromagnetic valve and a second electromagnetic valve, shifting a commutator to a position of a flowing water tank, opening a fourth electromagnetic valve and a water pump, and injecting water into the pressure-stabilizing water tower until an overflow pipe overflows;

step two, opening a third electromagnetic valve, and discharging water in the container into a water tank until the reading of the electronic scale is zero;

opening a first electromagnetic valve, and enabling the flow passing through the standard flowmeter to reach a set value by adjusting a flow regulating valve;

step four, closing the third electromagnetic valve, shifting the commutator to the position of the water quantity weigher, starting to count the pulse number of the standard flowmeter, stopping counting the pulses of the standard flowmeter after a preset time, simultaneously shifting the commutator to the position of the flow direction water tank, and reading the indication value m of the electronic scale and the accumulated pulse value N of the standard flowmeter;

calculating the volume V of the corresponding water according to the indicating value m of the electronic scale, and then calculating the meter coefficient K of the standard flowmeter measured at this time by using the following equation;

K＝N/V

and step six, repeating the step two to the step five to obtain a plurality of groups of instrument coefficients K, and calculating the average value Km of the instrument coefficients K.

8. The method of calibrating a variable head water flow rate standard device of claim 7, wherein the step of performing volumetric calculations on each volumetric section of the water tower in the calibrated variable head water flow rate standard device comprises the steps of:

step I, closing the first electromagnetic valve, the fourth electromagnetic valve and the water pump to stop the pressure stabilizing water tower;

step II, closing the sixth electromagnetic valve, opening the seventh electromagnetic valve and the first water pump, injecting water into the volume section water tower until the water level exceeds a first liquid level meter on the volume section water tower, and closing the first water pump;

step III, opening a fifth electromagnetic valve and a second electromagnetic valve, and adjusting a flow regulating valve to enable the flow passing through the standard flowmeter to reach the set value;

and IV, counting the number of pulses of the standard flowmeter when the water level of the water tower in the volume section is lowered to a first liquid level, recording the accumulated pulse number N1 of the standard flowmeter corresponding to the time from the first liquid level meter to the second liquid level meter when the water level is lowered to a second liquid level, recording the accumulated pulse number N2 of the standard flowmeter corresponding to the time from the second liquid level meter to the third liquid level meter when the water level is lowered to a third liquid level, recording the accumulated pulse number N3 of the standard flowmeter corresponding to the time from the third liquid level meter to the fourth liquid level meter when the water level is lowered to a fourth liquid level, and so on to obtain the accumulated pulse number Nm of each volume section corresponding to the standard flowmeter.

And step V, calculating the volume Vm of each volume segment by using the equation Vm as Nm/Km.

And VI, repeating the steps II to V to obtain a plurality of groups of volume values, calculating corresponding average values of the volume values to obtain the volume of each volume section of the volume section water tower, and setting the volume of each volume section to a variable water head water flow rate standard device for calibrating the calibrated flowmeter.

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