CN106679770B - Mass calibration system and method for mass flowmeter - Google Patents

Abstract

The invention provides a mass calibration system and a mass calibration method of a mass flowmeter, wherein the system comprises the following components: a calibration solution device for providing a solution required for mass flowmeter calibration; a solution pump for flowing a calibration solution within the calibration tubing; a plurality of mass flowmeters to be measured are uniformly arranged on the calibration pipeline; the actuator switch is used for adjusting the flow speed of the calibration solution in the calibration pipeline and adjusting the mass flow rate in the unit time in the calibration pipeline; a standard table for providing reference data for mass flow of the calibration solution within the calibration conduit; the computer is respectively connected with the mass flowmeter to be measured, the standard meter, the actuator switch and the electronic scale; the electronic balance is used for generating a control signal to adjust an actuator switch according to the reference data and reading the mass flow of the mass flowmeter to be measured and the mass flow of the standard meter according to the electronic balance; and the electronic scale is used for measuring the overflow flow mass of the measuring tube of the mass flowmeter. The invention improves the mass calibration precision and efficiency of the mass flowmeter.

Description

Quality calibration system and method for mass flow meter

Technical field

The invention belongs to the technical field of instrument calibration, and in particular relates to a mass calibration system and method for a mass flow meter.

Background technique

The Coriolis force mass flow meter is an instrument developed and designed using the principles of fluid mechanics. It is mainly used to measure the mass flow and density of gases and liquids, as well as the volume flow, total mass, and Total volume and other parameters required for the project. At this stage, in addition to being used for various conventional fluids, Coriolis force mass flow meters can also be used for various unconventional fluids, slurries, liquefied gases and compressed natural gas. They are widely used in petrochemicals, papermaking, food and pharmaceuticals, etc. Industry, its measurement accuracy is usually between 0.1-0.5%. Therefore, for manufacturers of Coriolis force mass flowmeters, they not only need to continuously improve the design, production and processing of Coriolis force mass flowmeter sensors, but also need to improve the quality of Coriolis force mass flowmeters. The calibration system of the flow meter instrument must also be scientifically and reasonably improved. Any production link of the complete Coriolis mass flow meter product, including the selection and welding of converter devices, the machining of sensor shunts, the shaping and welding of measuring tubes, the design of calibration system pipelines and the selection of calibration equipment, etc. All are related to the linearity, stability, repeatability, accuracy, temperature drift, etc. of the final Coriolis force mass flowmeter; therefore, verify the accuracy and practicality of the Coriolis force mass flowmeter product and its detection and calibration system. Sexual issues, then the two must be verified separately. If you want to test the accuracy, repeatability, stability and other related parameters of the Coriolis force mass flowmeter, then you should have a testing and calibration system that meets the national standard; on the contrary, if you want to test the Coriolis force mass flowmeter calibration system Accuracy, repeatability, stability and other related parameters, then there should be equipment that meets the calibration and measurement accuracy of the Orial force mass flowmeter, and the overall design error of the entire calibration system should be far lower than the Coriolis force mass flow rate The actual application accuracy of the meter. Only in this way can we design reasonable and scientific automated instruments and their calibration systems.

As shown in Figure 1, it is a schematic structural diagram of the existing Coriolis force mass flowmeter calibration system. Among them, the calibration solution device is a device used to hold the calibration medium solution; the solution pump provides source power for the calibration medium solution. , to ensure that the calibration medium solution can flow smoothly in the calibration pipeline; the flow direction switch is the switch that controls the flow of the calibration medium solution in the calibration pipeline; the calibration pipeline is the channel through which the calibration medium solution flows; the mass flow meter is the Coriolis force mass Flowmeter; fixed base frame, fixed cement pile to hold the Coriolis force mass flowmeter to be calibrated; flow size control switch, whose opening is adjusted by manual adjustment, with the purpose of adjusting the mass flow rate of the medium solution in the calibration pipeline size; electronic scale, measuring the quality of the medium solution passing through the mass flow measuring tube; drainage switch, a manual switch for discharging the medium solution in the electronic scale.

The calibration method flow of the calibration system in Figure 1 is detailed as follows:

Step 1. Turn off the flow direction switch, install the mass flowmeter to be calibrated on the calibration pipe as shown in Figure 1, and make the calibration pipe and the mass flowmeter installation flange in a sealed state without leakage. At the same time, ensure that the mass flowmeter The shell is vertical to the ground;

Step 2: Turn on the solution pump, adjust the flow direction switch, flow size control switch and electronic scale drainage switch to the maximum opening, so that the calibration medium solution flows in the calibration tube at the maximum flow rate, and maintain this state for at least 20 minutes. The purpose is to make the calibration The medium solution fills the entire calibration pipeline to eliminate air in the pipeline;

Step 3: Turn off the flow direction switch and flow control switch, and set the mass flow meter converter to be calibrated on the calibration pipeline to the automatic zero calibration state until it completes the automatic zero calibration;

Step 4: Adjust the flow control switch to the full opening state. When the calibration solution flow is stable, record the maximum phase difference corresponding to the sensor measurement tube of the current mass flowmeter sensor to be calibrated at the maximum flow rate;

Step 5: Based on the maximum phase difference corresponding to the sensor measurement tube at the maximum flow rate, select the flow calibration points of the mass flow meter to be calibrated, which are 1.0, 0.9, 0.8, and 1.0, 0.9, 0.8, and 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05 and 0.02 times points;

Step 6: Adjust the opening of the flow control switch to a point where the flow rate of the calibration solution in the calibration pipeline can cause the mass flowmeter sensor measurement tube to produce 1.0 times the maximum phase difference, and close the flow direction switch in the front section of the calibration pipeline until Until there is no calibration solution dripping from the electronic scale end of the calibration pipeline;

Step 7: Open the flow direction switch in the front section of the calibration pipeline. When the calibrated mass flow meter sensor is at the maximum flow rate and the maximum phase difference corresponding to the sensor measurement tube is 1.0 times the point, delay the calibration measurement for 7-10 minutes and close the flow direction switch. Until there is no calibration solution dripping from the electronic scale end of the calibration pipeline, record the total measurement mass of all current mass flowmeter converters to be calibrated and the total measurement volume of the electronic scale;

Step 8: Repeat steps 6 to 7 to complete the calibration of other phase difference calibration points;

Step 9: Based on the calibration data, calculate the mass flow coefficient corresponding to each mass flow meter to be calibrated, and write the coefficient into the EEPROM of the mass flow meter converter through key operation.

Step 10: Perform accuracy testing and repeatability testing of the mass flow meter.

Step 11, adjust the flow control switch to the full opening state, and record the maximum mass flow rate output by the mass flow meter converter on the current calibration pipeline;

Step 12: Based on the maximum mass flow rate, select points 1.0, 0.75, 0.50, 0.25 and 0.1 times the maximum mass flow rate as the accuracy and repeatability detection points of the mass flow meter;

Step 13: Adjust the flow size control switch to 1.0 times the maximum mass flow rate output by the mass flow meter converter, delay measurement for 7-10 minutes, and turn off the flow direction switch until there is no solution dripping from the electronic scale end of the calibration pipeline, in sequence. Record the total mass output of all mass flowmeter converters to be calibrated and the total mass of the electronic scale;

Step 14: Repeat the measurement 3 times at the 1.0 times maximum mass flow rate point, and calculate the accuracy and repeatability of the current detection point;

Step 15: Repeat steps 13 to 14 to complete the detection of other mass flow detection points.

The existing Coriolis force mass flow meter mass flow calibration system can accommodate the mass flow calibration of up to 2 mass flow meters. The entire calibration process includes the adjustment of the calibration flow, data recording during the calibration process, and calculation of the corresponding The ground coefficient, as well as the accuracy and repeatability detection data when the calibration is completed, require manual operations. Human operation will inevitably affect the accuracy and repeatability of the entire instrument. In addition, a large number of experiments and tests have shown that in the calibration system, during the production and calibration process of the solution pump and calibration pipeline, there is always a certain amount of air bubbles brought into the calibration pipeline, and the work of the solution pump will also cause the inside of the calibration pipeline to The calibration solution produces trickle flow. These factors greatly reduce the accuracy of the entire mass flow meter mass flow calibration system.

Contents of the invention

In view of the above shortcomings of the prior art, the purpose of the present invention is to provide a mass calibration system and method for a mass flow meter, which is used to solve the problem that the mass flow meter in the prior art requires manual operation during mass flow calibration, resulting in the entire The problem of low efficiency and low accuracy of mass flow meter calibration.

In order to achieve the above objects and other related objects, the present invention provides a mass calibration system for a mass flow meter, including:

Calibration solution device, which is used to provide the calibration solution required for mass flow meter calibration; solution pump, which is used to provide power to flow the calibration solution into the calibration pipeline at a certain pressure; standard meter, which is installed in the calibration pipeline along the output direction of the solution pump on the calibration pipeline, which is used to provide reference data for the mass flow of the calibration solution in the calibration pipeline; multiple mass flow meters to be measured are evenly installed on the calibration pipeline along the output direction of the standard meter; an actuator switch is used to control the calibration pipeline Whether the internal calibration solution flows is also used to adjust the mass flow of the calibration solution in the calibration pipeline per unit time; the computer is connected to the mass flow meter, standard table, actuator switch and electronic scale respectively; it is used to determine the size of the reference data according to the size of the reference data. Adjust the opening of the actuator switch, and read the mass flow meter to be measured according to the electronic scale; the electronic scale is connected to the actuator switch and is used to measure the flow quality of the mass flow meter calibration pipeline overflow.

Preferably, the actuator switch includes a first actuator switch and a second actuator switch. The first actuator switch is installed on the calibration pipeline between the standard meter and the solution pump, and is used to adjust the first actuator switch according to the first output of the computer. The control signal controls whether the calibration solution flows in the calibration pipeline; the second actuator switch is installed on the calibration channel between the electronic scale and the mass flow meter close to it, and is used to adjust the calibration pipeline according to the second control signal output by the computer. The mass flow rate of the internal calibration solution per unit time.

Preferably, a constant pressure and constant current tank is provided between the solution pump and the actuator switch, which is used to eliminate trickle flow in the calibration solution and air bubbles carried in the calibration solution.

Preferably, both sides of each mass flow meter and standard meter are provided with fixed frames for supporting their work.

Preferably, the electronic scale is connected to a drainage control valve controlled by the computer.

Preferably, the computer is connected to the actuator switch, standard meter, mass flow meter, electronic scale and drainage control valve respectively through the control bus.

Preferably, the number of mass flow meters to be tested is at most five.

The object of the present invention is also to provide a mass calibration method for a mass flow meter, including:

Step 1: Set the aperture value and upper limit value according to the type of mass flow meter to be tested;

Step 2, adjust the first actuator switch and the second actuator switch until there is no leakage from the mass flow meter to be tested;

Step 3: When the first actuator switch and the second actuator switch are both adjusted to the full opening, until there are almost no bubbles in the calibration pipe, standard meter and measuring tube of the mass flow meter;

Step 4: When both the first actuator switch and the second actuator switch are adjusted to the zero opening, obtain the current first reading of the standard meter; detect whether the calibration solution in the calibration pipeline is in a flowing state, and if the calibration solution is not flowing When in the flow state, the automatic zero calibration command is broadcast to the mass flow meter to be measured, and the drainage control valve is adjusted to be closed until the automatic zero calibration is completed;

Step 5: Select the calibration point of the mass flow meter according to the type and range of the mass flow meter to be measured. The calibration point selects a multiple point of the measuring range as the selection point, where the multiple points include 1.0, 0.9, 0.8, 0.7, and 0.6. , 0.5, 0.4, 0.3, 0.2, 0.1, 0.05 and 0.02;

Step 6: Calibrate a selected point as the quality process calibration point, adjust the first actuator switch to the full opening, and obtain the current second reading of the standard meter; calculate the mass flow rate based on the second reading close to the selected point. Adjust the opening of the second actuator switch until the mass flow meter to be measured reaches the mass flow calibration point corresponding to the selected point;

Step 7: Adjust the first actuator switch to the zero opening, and keep the opening of the second actuator switch unchanged until there is no calibration solution dripping between the calibration pipe and the electronic scale;

Step 8: Clear the standard table and the total mass output by the mass flow meter to be measured, record the current reading of the electronic scale and clear it to zero;

Step 9: Adjust the first actuator switch to the full opening, and calibrate the mass flow meter to be measured at the multiple point corresponding to the selected point as the mass flow calibration point according to the preset time delay;

Step 10, adjust the first actuator switch to zero opening, and obtain whether the current reading of the standard meter is zero. If the current reading of the standard meter is zero and there is no calibration solution dripping between the calibration pipe and the electronic scale, obtain And record the total mass output by each mass flow meter to be measured and the total mass of the electronic scale calibration solution;

Step 11: Repeat steps 6 to 10 to complete the calibration of the mass process calibration points of other selected points in sequence; calculate the mass flow coefficient of each mass flow meter based on the calibration data, and store the mass flow coefficient in the mass flow meter to be measured ;

Step 12: Re-screen the measuring range multiple points of the mass flow meter as selection points. Perform accuracy and repeatability testing on each selection point according to steps 6 to 11, and record the calibration and testing results of the mass flow meter to be tested.

Further, before step 2, it also includes:

Check whether the constant pressure and constant current tank is in a full tank and constant pressure state. If it is not in a full tank and constant pressure state, turn on its exhaust switch until the solution pump changes the constant pressure and constant current tank to a full tank and constant pressure state.

As mentioned above, the mass flow meter calibration system and method of the present invention have the following beneficial effects:

By replacing the original manually operated calibration system with a computer-controlled calibration system, the computer is used to send control signals to adjust the opening of the actuator switch to control the flow rate of the calibration solution in the calibration pipeline. The original calibration system can only Two mass flow meters are calibrated, but now five can be calibrated at the same time. Moreover, no human participation is required during the calibration process, which not only improves the efficiency of mass flow meter calibration, but also greatly improves the calibration accuracy of mass flow meters; at the same time, in A constant pressure and constant flow tank is introduced into the calibration system, which eliminates the problems of calibration solution trickle and air bubbles produced when the solution pump is working, and essentially improves the calibration accuracy of the mass flow meter.

Description of drawings

Figure 1 shows a schematic structural diagram of an existing Coriolis force mass flowmeter calibration system provided by the present invention;

Figure 2 shows a structural block diagram of the calibration system of a mass flow meter of the present invention;

Figure 3 shows a structural diagram of a calibration system for a mass flow meter according to an embodiment of the present invention;

Figure 4 shows a flow chart of a calibration method of a mass flow meter according to the present invention.

Detailed ways

The implementation of the present invention is described below with specific embodiments. Those familiar with this technology can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

See Figure 2 to Figure 4. It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to coordinate with the content disclosed in the specification for the understanding and reading of those familiar with this technology, and are not used to limit the implementation of the present invention. Restrictive conditions, so they have no technical substantive significance. Any structural modifications, changes in proportions, or adjustments in size should still fall within the scope of the present invention as long as they do not affect the effects that the present invention can produce and the purposes that can be achieved. The technical content disclosed must be within the scope that can be covered. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for convenience of description and are not used to limit the scope of this specification. The scope of the invention that can be implemented, and changes or adjustments in their relative relationships, as long as there is no substantial change in the technical content, shall also be regarded as the scope of the invention that can be implemented.

Please refer to Figure 2. The present invention provides a structural block diagram of a calibration system for a mass flow meter, including:

Calibration solution device 1, which is used to provide the calibration solution required for mass flow meter calibration; solution pump 3, which is used to provide power to flow the calibration solution into the calibration pipeline at a certain pressure; standard table 4, which is installed along the output direction of the solution pump On the calibration pipeline, it is used to provide reference data for the mass flow of the calibration solution in the calibration pipeline; multiple mass flow meters 5 to be measured are evenly installed on the calibration pipeline along the output direction of the standard table 4; the actuator switch 2, It is used to control whether the calibration solution in the calibration pipeline flows, and is also used to adjust the mass flow rate of the calibration solution in the calibration pipeline within unit time; the computer 6 is connected to the mass flow meter 5, the standard table 4, the actuator switch 2 and the electronic computer respectively. Scale 7; which is used to adjust the opening of the actuator switch 1 according to the size of the reference data, and read the mass flow meter 5 to be measured according to the electronic scale 7; electronic scale 7, which is connected to the actuator switch 2 , used to measure the flow quality of the mass flow meter 5 to calibrate the pipe overflow.

In this embodiment, the mass flow meter 5, standard table 4, actuator switch 2 and electronic scale 7 are automatically controlled by the computer. The entire calibration process does not require manual participation, eliminating human instability factors and not only improving the efficiency of calibration, but also It also improves the accuracy of calibration.

Specifically, the actuator switch 2 includes a first actuator switch and a second actuator switch. The first actuator switch 2 is installed on the calibration pipeline between the standard meter and the solution pump, and is used to adjust the output according to the computer output. The first control signal controls whether the calibration solution flows in the calibration pipeline; the second actuator switch 2 is installed on the calibration channel between the electronic scale and the mass flow meter close to it, and is used to control the flow of the calibration solution according to the second control signal output by the computer. Adjust the mass flow rate of the calibration solution in the calibration pipeline per unit time.

On the basis of the above structure, a constant pressure and constant current tank can also be provided between the solution pump 3 and the actuator switch 2. The input end of the constant pressure and constant current tank is connected to the calibration pipeline of the output of the solution pump 3. The output end of the constant pressure and constant current tank is connected to the actuator switch 2 through the calibration pipeline. The constant pressure and constant current tank is used to eliminate the trickle flow in the calibration solution and the air bubbles carried in the calibration solution.

Specifically, both sides of each mass flow meter 5 and standard meter 4 are provided with fixed racks for supporting their work, that is, there are fixed racks on both sides of the standard meter and the mass flow meter, and the fixed racks are The frame is preferably a cement frame. It can not only eliminate the impact of the vibration of the calibration pipeline on the mass flow calibration instrument, but also eliminate the impact of the mechanical vibration of the mass flow meter sensor itself on the mass flow calibration. At the same time, the fixed frame also plays a role in isolating the online mass flow meters of the whole machine to be calibrated to prevent mutual influence between the mass flow meters of the whole machine to be calibrated.

Specifically, the electronic scale 7 is connected to a drainage control valve controlled by the computer. The drainage control valve is connected to the computer 6 using a bus control, and the drainage control valve switch is controlled according to the control signal sent by the computer, such as: During the calibration process of the mass flow meter, always close the drainage control valve; every time the mass flow meter is calibrated, open the drainage control valve until the mass flow in the electronic scale is exhausted.

Specifically, the computer 6 is connected to the actuator switch 2, the standard meter 4, the mass flow meter 5, the electronic scale 7 and the drainage control valve respectively through the control bus; the computer can also be replaced by a central control computer, an intelligent device or a terminal, and the computer passes The bus control method, and reading the reference data in the standard table are used as the basis for controlling the actuator switch 2. That is, the basis for the regulator to control the opening of the actuator switch mainly depends on the instantaneous mass flow rate of the standard meter metering output. The standard meter If the instantaneous mass flow rate of the metering output is small, the opening of the second actuator switch will be small; otherwise, if the instantaneous mass flow rate of the standard meter metering output is large, the opening of the second actuator switch will be large, which can improve the control accuracy of the actuator switch.

Moreover, the number of mass flow meters 5 to be measured is at most five. Compared with the original calibration system, which can only calibrate two mass flow meters at most, the calibration efficiency is improved.

As shown in Figure 3, it is a structural diagram of an embodiment of a mass flow meter calibration system of the present invention, including:

In this embodiment, the calibration solution device 1 provides the calibration solution required for calibration to the solution pump 3. Under the action of the constant pressure and constant flow tank, the solution pump 3 ensures that the calibration pipelines in the entire calibration system are constant flow. Constant pressure can eliminate the influence of a large number of bubbles in the calibration solution on the calibration accuracy; the computer 6 is connected to the first actuator switch, the second actuator switch, the standard table 4, and the five to be tested (to be calibrated) through bus control. The mass flow meter 5, the electronic scale 7, and the drainage control valve are all connected to each other through calibration pipelines. The standard meter and the five mass flow meters to be measured follow the constant pressure and constant flow in order from left to right. The output direction of the tank is evenly distributed on the calibration pipe, and there is a supporting fixed frame below the calibration pipe (as above, I will not go into details here); during each calibration, the reference data of the standard table is read as a control for the second actuator. The basis for the size of the switch opening; the switch that opens and stops the flow of the calibration solution in the calibration pipeline by controlling the first actuator switch; and the computer records the flow quality measured by the electronic scale for each calibration, based on the corresponding multiple points. The flow quality calculates the mass flow coefficient of each mass flow meter, and saves the mass flow coefficient to the corresponding mass flow meter; at the same time, the drainage control valve is controlled to open, so that the calibration solution of the electronic scale is cleared to prepare for the next calibration.

As shown in Figure 4, it is a flow chart of the calibration method of a mass flow meter of the present invention, including:

Step 1: Set the aperture value and upper limit value according to the type of mass flow meter to be tested;

Step 2, adjust the first actuator switch and the second actuator switch until there is no leakage from the mass flow meter to be tested;

Step 3: When both the first actuator switch and the second actuator switch are adjusted to full opening, keep this state for at least ten minutes (until there are almost no bubbles in the calibration pipe, standard meter and measuring tube of the mass flow meter) ;

Step 4: When both the first actuator switch and the second actuator switch are adjusted to the zero opening, obtain the current first reading of the standard meter; detect whether the calibration solution in the calibration pipeline is in a flowing state, and if the calibration solution is not flowing When in the flow state, the automatic zero calibration command is broadcast to the mass flow meter to be measured, and the drainage control valve is adjusted to be closed until the automatic zero calibration is completed;

Step 5: Select the calibration point of the mass flow meter according to the type and range of the mass flow meter to be measured. The calibration point selects a multiple point of the measuring range as the selection point, where the multiple points include 1.0, 0.9, 0.8, 0.7, and 0.6. , 0.5, 0.4, 0.3, 0.2, 0.1, 0.05 and 0.02;

Step 6: Calibrate a selected point as the quality process calibration point, adjust the first actuator switch to the full opening, and obtain the current second reading of the standard meter; calculate the mass flow rate based on the second reading close to the selected point. Adjust the opening of the second actuator switch until the mass flow meter to be measured reaches the mass flow calibration point corresponding to the selected point;

Step 7: Adjust the first actuator switch to zero opening, and keep the second actuator switch opening unchanged (at least two minutes) until there is no calibration solution dripping between the calibration pipe and the electronic scale;

Step 8: Clear the standard table and the total mass output by the mass flow meter to be measured, record the current reading of the electronic scale and clear it to zero;

Step 9: Adjust the first actuator switch to the full opening, and calibrate the mass flow meter to be measured at the multiple point corresponding to the selected point as the mass flow calibration point according to the preset time delay;

Step 10, adjust the first actuator switch to zero opening, and obtain whether the current reading of the standard meter is zero. If the current reading of the standard meter is zero and there is no calibration solution dripping between the calibration pipe and the electronic scale, obtain And record the total mass output by each mass flow meter to be measured and the total mass of the electronic scale calibration solution;

Step 11: Repeat steps 6 to 10 to complete the calibration of the mass process calibration points of other selected points in sequence; calculate the mass flow coefficient of each mass flow meter based on the calibration data, and store the mass flow coefficient in the mass flow meter to be measured .

Step 12: Re-screen the measuring range multiple points of the mass flow meter as selection points. Perform accuracy and repeatability testing on each selection point according to steps 6 to 11, and record the calibration and testing results of the mass flow meter to be tested.

According to the calibration method of the mass flow meter mentioned above, the details are as follows:

1. Initialize the mass flow meter mass flow calibration system in the computer, select a new round of mass flow calibration, and select and set the caliber size and mass flow rate of the mass flow meter to be calibrated based on the type of mass flow meter sensor that is actually produced and calibrated. Calibrated upper limit;

2. Control the first adjustment actuator switch and the second actuator switch to the closed state, that is, the opening is 0;

3. Check whether the constant pressure and constant current tank is in a full tank and constant pressure state. If it is not in a full tank and constant pressure state, turn on the exhaust switch on the constant pressure and constant current tank device to maximize the filling of the calibration solution supplied by the solution pump. Turn off the exhaust switch after the constant pressure and constant current tank. The purpose is to eliminate the presence of air bubbles in the calibration solution and the non-constant pressure and constant flow state of the calibration solution;

4. Install the complete mass flow meter to be calibrated on the calibration pipeline. The calibration system can accommodate up to 5 complete mass flow meters. If there are less than 5, the pipeline will be directly connected;

5. Control and adjust actuator switch 1 and actuator switch 2 until the opening is 50%, and observe whether there is leakage at the flange connection between the calibration pipe and the mass flow meter of the whole machine; if there is no leakage, pass the mass flow calibration The system software controls and adjusts the first actuator switch and the second actuator switch to the 100% opening point, and then observes again whether there is any leakage at the flange connection between the calibration pipeline and the mass flow meter of the whole machine; if there is still no leakage, then Continue working for about 5 minutes, and adjust the first actuator switch and the second actuator switch to the closed state through the mass flow calibration system software control. If leakage occurs during installation and testing, human intervention is required for reinstallation.

6. Start the mass flow calibration process of the mass flow calibration system software;

7. Control and adjust actuator switch 1 and actuator switch 2 to the 100% opening point, so that they can continue to work in this state for 10 minutes. This process is to fully fill the calibration pipe and standard meter with the calibration solution and the mass flow rate to be calibrated. In the measuring tube of the meter sensor, the accuracy effect caused by bubbles is eliminated;

8. Control and adjust actuator switch 1 and actuator switch 2 to the 0% opening point, then obtain the real-time output status of the standard table through the data bus, monitor whether there is a solution flow state in the calibration pipeline, and if there is no solution flow, the mass flow The calibration system software sends a broadcast of automatic zero calibration quality to all online mass flow meters to be calibrated, and at the same time controls the drainage control valve to be closed and waits for the zero calibration to be completed;

9. Select the calibration point according to the type and range of the mass flowmeter sensor to be calibrated. Usually 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1 of the mass flow range of the mass flowmeter to be calibrated are selected. , 0.05 and 0.02 points are the selected points for mass flow calibration;

10. Calibrate the mass flow calibration point with a mass flow range of 1.0 times the mass flow range of the mass flow meter to be calibrated. The mass flow calibration system software controls and adjusts the actuator switch 1 to the 100% opening point, obtains the real-time mass flow output value of the standard meter through the data bus, and determines whether the actual mass flow output value reaches or is close to the quality of the mass flow meter to be calibrated. The mass flow range of the mass flow rate is 1.0 times the point to adjust the opening of the actuator switch 2 so that its opening meets the mass flow calibration point of the mass flow meter to be calibrated. The mass flow rate range is 1.0 times;

11. Control and adjust the actuator switch 1 to be in the closed state, the opening of the actuator switch 2 remains unchanged, and delay for 2 minutes; the purpose of the delay is to wait until there is no calibration solution dripping between the calibration pipeline terminal and the electronic scale;

12. Clear the total mass measured by the standard table and the mass flow meter to be calibrated, and record and clear the total mass value measured by the electronic scale (record the total mass measured by the electronic scale each time, and calculate the total mass measured each time. Add up and judge whether the cumulative total reaches or is close to the limit value of the weighing. If it reaches or is close, the mass flow calibration system software controls the drainage control valve to be in the open state through the control bus, and the electronically weighed metering solution is All emissions are discharged, and the cumulative total in the mass flow calibration system software is also cleared).

13. Control and adjust the opening state of the actuator switch from 1 to 100%, perform the mass flow calibration point calibration of the mass flow meter to be calibrated to 1.0 times the mass flow range, and delay the measurement calibration for 6 minutes (the delay time can be set) ;

14. Control and adjust the opening status of the actuator switch from 1 to 0%, and obtain the real-time mass flow output value of the standard meter through the data bus to see if it is 0. If it is 0, wait for a delay and there is no calibration solution between the calibration pipeline terminal and the electronic scale. When dripping, the mass flow calibration system software obtains and records the total mass measured online corresponding to the output of each mass flow meter and the total mass of the electronic weighing calibration solution through the data bus;

15. Repeat steps 10)-14) to complete the calibration of mass flow at 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05 and 0.02 times of the online mass flow measurement range to be calibrated;

16. Calculate the mass flow coefficient corresponding to each mass flow meter online based on the calibration data, and write the coefficient into the EEPROM of the corresponding mass flow meter converter through the data bus.

17. Automatically start the accuracy and repeatability testing of the online mass flow meter;

18. The 1.0, 0.75, 0.50, 0.25 and 0.1 times of the online mass flow measurement range are usually selected as the accuracy and repeatability testing points of the mass flow meter;

19. Carry out mass flow calibration point verification with a mass flow rate of 1.0 times. The mass flow calibration system software controls and adjusts the actuator switch 1 to the 100% opening point, obtains the real-time mass flow output value of the standard meter through the data bus, and determines whether the actual mass flow output value reaches or is close to the mass flow rate of the mass flow meter to be measured. The mass flow rate of the measuring range is 1.0 times the mass flow point to adjust the opening of the actuator switch 2 so that its opening meets the mass flow rate point of the mass flow meter mass flow rate of 1.0 times;

20. Control and adjust the actuator switch 1 to be in the closed state, the opening of the actuator switch 2 remains unchanged, and delay for 2 minutes; the purpose of the delay is to wait until there is no calibration solution dripping between the calibration pipeline terminal and the electronic scale;

21. Clear the total mass measured by the standard table and the mass flow meter to be calibrated, and record and clear the total mass measured by the electronic scale.

22. Control and adjust the opening state of the actuator switch from 1 to 100%, perform mass flow point accuracy and repeatability testing of the mass flow meter with a mass flow range of 1.0 times, and perform measurement verification with a delay of 6 minutes;

23. Control and adjust the opening state of the actuator switch from 1 to 0%, and obtain the real-time mass flow output value of the standard meter through the data bus to see if it is 0. If it is 0, wait for a delay and there is no calibration solution between the calibration pipeline terminal and the electronic scale. When dripping, the mass flow calibration system software obtains and records the total mass measured online corresponding to the output of each mass flow meter and the total mass of the electronic weighing calibration solution through the data bus;

24. Repeat steps 21)-23) to complete the second accuracy and repeatability test of the mass flow calibration point with a mass flow rate of 1.0 times;

25. Repeat steps 21)-23) to complete the third accuracy and repeatability test of the mass flow calibration point with a mass flow rate of 1.0 times;

26. Repeat steps 19)-25) to complete the accuracy and repeatability testing of mass flow points of 0.75, 0.50, 0.25 and 0.1 times;

27. Report the calibration and testing results (accuracy and repeatability) of the online mass flow meter to the production user.

To sum up, the present invention replaces the original manually operated calibration system with a computer-controlled calibration system, and uses the computer to send control signals to adjust the opening of the actuator switch to control the flow rate of the calibration solution in the calibration pipeline. The previous calibration system could only calibrate two mass flow meters at most, but now it can calibrate five mass flow meters at the same time. Moreover, no human participation is required during the calibration process, which not only improves the efficiency of mass flow meter calibration, but also greatly improves the mass flow rate. At the same time, a constant pressure and constant flow tank is introduced into the calibration system, which eliminates the problems of calibration solution trickle and air bubbles produced by the solution pump during operation, and essentially improves the calibration accuracy of the mass flow meter. . Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

The above embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims (7)

1. A mass calibration system for mass flow meters, which is characterized in that it includes: Calibration solution device, which is used to provide calibration solution required for mass flow meter calibration; Solution pump, which is used to provide power to flow the calibration solution in the calibration pipeline at a certain pressure; The standard meter is installed on the calibration pipeline along the output direction of the solution pump. It is used to provide reference data for the mass flow of the calibration solution in the calibration pipeline; A plurality of mass flow meters to be measured are evenly installed on the calibration pipeline along the output direction of the standard meter, and the number of the mass flow meters to be measured is at most five; The actuator switch is used to control whether the calibration solution flows in the calibration pipeline, and is also used to adjust the mass flow rate of the calibration solution in the calibration pipeline within unit time; wherein the actuator switch includes a first actuator switch, a second actuator switch, and a second actuator switch. The first actuator switch is installed on the calibration pipeline between the standard meter and the solution pump, and is used to control whether the calibration solution flows in the calibration pipeline according to the first control signal output by the computer; the second actuator switch Installed on the calibration channel between the electronic scale and the mass flow meter close to it, it is used to adjust the mass flow rate of the calibration solution in the calibration pipeline per unit time according to the second control signal output by the computer; A constant pressure and constant current tank is provided between the solution pump and the first actuator switch, which is used to eliminate trickle flow in the calibration solution and air bubbles in the calibration solution; A computer, which is connected to the mass flow meter, standard meter, actuator switch and electronic scale respectively; which is used to adjust the opening of the actuator switch according to the size of the reference data, and read the mass flow meter to be measured according to the electronic scale; An electronic scale is connected to the actuator switch and is used to measure the flow quality of the mass flow meter calibration pipeline overflow. 2. The mass calibration system of the mass flow meter according to claim 1, characterized in that, each of the mass flow meters and the standard meter is provided with a fixed frame on both sides for supporting its work. 3. The mass calibration system of the mass flow meter according to claim 1, characterized in that the computer is connected to the actuator switch, the standard meter, the mass flow meter and the electronic scale respectively through the control bus. 4. The mass calibration system of the mass flow meter according to claim 1, wherein the electronic scale is connected to a drainage control valve controlled by the computer. 5. The quality calibration system of the mass flow meter according to claim 4, characterized in that the computer and the drainage control valve are connected by a control bus. 6. A method for using the mass calibration system of the mass flowmeter according to any one of claims 1 to 5, characterized in that it includes: Step 1: Set the aperture value and upper limit value according to the type of mass flow meter to be tested; Step 2, adjust the first actuator switch and the second actuator switch until there is no leakage from the mass flow meter to be tested; Step 3: When the first actuator switch and the second actuator switch are both adjusted to the full opening, until there are almost no bubbles in the calibration pipe, standard meter and measuring tube of the mass flow meter; Step 4: When both the first actuator switch and the second actuator switch are adjusted to the zero opening, obtain the current first reading of the standard meter; detect whether the calibration solution in the calibration pipeline is in a flowing state, and if the calibration solution is not flowing When in the flow state, the automatic zero calibration command is broadcast to the mass flow meter to be measured, and the drainage control valve is adjusted to be closed until the automatic zero calibration is completed; Step 5: Select the calibration point of the mass flow meter according to the type and range of the mass flow meter to be measured. The calibration point selects a multiple point of the measuring range as the selection point, where the multiple points include 1.0, 0.9, 0.8, 0.7, and 0.6. , 0.5, 0.4, 0.3, 0.2, 0.1, 0.05 and 0.02; Step 6: Calibrate a selected point as the quality process calibration point, adjust the first actuator switch to the full opening, and obtain the current second reading of the standard meter; calculate the mass flow rate based on the second reading close to the selected point. Adjust the opening of the second actuator switch until the mass flow meter to be measured reaches the mass flow calibration point corresponding to the selected point; Step 7: Adjust the first actuator switch to the zero opening, and keep the opening of the second actuator switch unchanged until there is no calibration solution dripping between the calibration pipe and the electronic scale; Step 8: Clear the standard table and the total mass output by the mass flow meter to be measured, record the current reading of the electronic scale and clear it to zero; Step 9: Adjust the first actuator switch to the full opening, and calibrate the mass flow meter to be measured at the multiple point corresponding to the selected point as the mass flow calibration point according to the preset time delay; Step 10, adjust the first actuator switch to zero opening, and obtain whether the current reading of the standard meter is zero. If the current reading of the standard meter is zero and there is no calibration solution dripping between the calibration pipe and the electronic scale, obtain And record the total mass output by each mass flow meter to be measured and the total mass of the electronic scale calibration solution; Step 11: Repeat steps 6 to 10 to complete the calibration of the mass process calibration points of other selected points in sequence; calculate the mass flow coefficient of each mass flow meter based on the calibration data, and store the mass flow coefficient in the mass flow meter to be measured ; Step 12: Re-screen the measuring range multiple points of the mass flow meter as selection points. Perform accuracy and repeatability testing on each selection point according to steps 6 to 11, and record the calibration and testing results of the mass flow meter to be tested. 7. The mass calibration method of the mass flow meter according to claim 6, characterized in that before the step 3, it also includes: detecting whether the constant pressure and constant flow tank is in a full tank and constant pressure state, if it is not in a full tank In the constant pressure state, turn on its exhaust switch until the solution pump changes the constant pressure and constant current tank to a full tank and constant pressure.