CN204330091U - Bell jar type gas flowmeter calibrating installation - Google Patents

Abstract

The utility model discloses a bell jar type gas flow meter verification device. It includes a bell-type gas flow standard device, a measured flow meter, and a computer control system. The bell-type gas flow standard device has a pressure sensor P A, a temperature sensor T _{A and} a temperature sensor T _A+ , a pressure sensor P _A and a temperature sensor T The signal output terminals of _{A and} T _A+ are connected to the signal acquisition terminal of the computer control system; the front ends of multiple measured flowmeters are connected to an air intake pipeline, and the intake pipeline extends into the bell-type gas flow standard device. The front ends of each measured flow meter are provided with a pressure sensor P _B and a temperature sensor T _B , and the pressure sensor P _B , temperature sensor T _B and the pulse signal output ends of the measured flow meters are all connected to the signal acquisition end of the computer control system. After adopting the above-mentioned structure, its structure setting is reasonable, the degree of automation is high, not only the detection efficiency is greatly improved, but also the detection accuracy is very high.

Description

Bell type gas flowmeter verification device

technical field

The utility model relates to a testing device suitable for various gas volumetric flowmeters, in particular to a testing device for cover-type gas flowmeters.

Background technique

The use of bell-jar gas flow standard devices to verify various flowmeters has only been realized in recent years. For gas volumetric flowmeters, using bell jars as standard devices is the most reasonable verification method. At present, there are many devices in China that use bell-type gas flow standard devices to verify gas volume flowmeters, but the technical indicators and configurations are not high. The indicators and configurations are generally: (10-500) L bell pressure It is about 1.3kPa, the bell jar pressure of 1000L is about 1.6kPa, the bell jar pressure of 2000L is about 2kPa, the device expansion uncertainty is Ur=0.5%, (k=2), the pipeline connection method is hose connection, the control The operation mode is manual, and the verification results are processed by manual calculation. Basically, no temperature and pressure transmitters are configured, and the number of meters for each inspection is one flowmeter. It can be seen that using the existing bell jar type gas flow standard device to verify the flowmeter has low bell jar pressure, can only detect a single meter, has low efficiency, has large uncertainties, and cannot truly reflect the metering performance of the flowmeter Good or bad etc.

Contents of the invention

The technical problem to be solved by the utility model is to provide a bell jar type gas flowmeter verification device with high bell jar pressure, high degree of automation, high efficiency and high detection accuracy.

In order to solve the above-mentioned technical problems, the bell-jar type gas flowmeter verification device of the present invention includes a bell-type gas flow standard device, a measured flow meter, and a computer control system. The bell-type gas flow standard device has a The pressure sensor P _A and temperature sensor T _A in the flow standard device and the temperature sensor T _A+ located outside the bell type gas flow standard device, the signal output terminals of the pressure sensor P _A and temperature sensors T _A and T _A+ are connected to the computer control system signal acquisition end; the front ends of multiple measured flowmeters are connected to an air intake pipeline, and the air intake pipeline extends into the bell type gas flow standard device, and the front end of each measured flowmeter is provided with a The pressure sensor P _B and the temperature sensor _TB on the gas pipeline, the pulse signal output terminals of the pressure sensor P _B , the temperature sensor _TB and the measured flow meter are all connected to the signal acquisition terminal of the computer control system.

The plurality of measured flow meters are connected in series to the intake pipeline.

The plurality of series-connected measured flowmeters are connected in parallel on the intake pipeline.

Each of the measured flow meters is respectively connected in parallel on the intake pipeline.

The back end of the measured flow meter is connected to a back pressure pipeline, and a control valve is provided on the back pressure pipeline, and the signal input end of the control valve is connected to the signal output end of the computer control system.

There is a pneumatic switch valve on the air intake pipeline, and the signal output end of the pneumatic switch valve is connected to the signal acquisition end of the computer control system.

The front ends of the measured flow meters each have a section of straight pipe, on which the pressure sensor P _B and the temperature sensor _TB are located.

There is a section of straight pipe at the front end of the measured flowmeter located at the most front end, the pressure sensor P _B and the temperature sensor T _B are located on the straight pipe, and the front ends of each measured flow meter located at the rear are provided with connecting pipes with rectification devices , the pressure sensor PC _and temperature sensor T _C are installed on the connecting pipe, the pressure sensors P _B , _PC , temperature sensors T _B , T _C and the pulse signal output terminals of each measured flow meter are connected to the signal acquisition of the computer control system end.

A telescopic tube is also arranged between the measured flow meter and the control valve.

The bell-type gas flow standard device is set as a large bell-type gas flow standard device and a small bell-type gas flow standard device, the large bell-type gas flow standard device is used to verify the large flow rate of the flowmeter, and the small bell-type The gas flow standard device is used to verify the small flow rate of the flowmeter, the pressure sensor P A and the temperature sensor T A located in the large bell type gas flow standard device and the small bell type gas flow standard device and the pressure sensor P _A and the temperature sensor T _A located in the large bell type gas flow standard device The signal output terminals of the temperature sensor TA ₊ outside the standard device and the small bell type gas flow standard device are all connected to the signal acquisition terminal of the computer control system; there are two sets of pneumatic switch valves on the air intake pipeline, and the computer control system can The parameters of the flowmeter to be tested are controlled by two sets of pneumatic valves to automatically select the bell type gas flow standard device and the pipe diameter.

After the above-mentioned structure is adopted, the pressure and temperature in front of each measured flowmeter can be detected during the detection process, and the temperature and pressure in the bell-type gas flow standard device can be detected at the same time, and sent to the computer controller, and the computer control system collects the bell In the bell-type gas flow standard device, the temperature and pressure in the bell jar and the pressure and temperature in front of the flowmeter can be compared and processed by the computer to compensate for the temperature and pressure changes, and a rectification device is installed between every two tested meters, which can The airflow discharged from the volumetric meter cavity in the upstream is uniform, which makes the airflow more stable and ensures less pressure loss when the gas flows through, which can meet the required pressure of the two flowmeters; two high-pressure bell jars set at the same time are combined into a standard device , the computer control system can automatically select the standard device and pipeline caliber through two sets of control pneumatic valves according to the input parameters of the tested flowmeter, so that two sets of flowmeters of the same type can be verified each time, and the standard device and pipeline can be automatically selected After caliber, the computer control system will collect the temperature and pressure in the corresponding bell jar and each measured flowmeter pipeline through the temperature and pressure sensor and temperature and pressure transmitter, and compare and process the temperature through the computer Pressure change compensation, each flowmeter pipeline and the corresponding temperature and pressure change compensation system in the bell jar are independent, and each verification is collected from the corresponding bell jar gas flow standard device and the flowmeter pipeline temperature and pressure, and then perform temperature and pressure change compensation to determine the accuracy of the tested flowmeter. The computer control system controls the control valve to precisely control the instantaneous flow rate. Its structure is reasonable and the degree of automation is high. Also very high.

Description of drawings

Fig. 1 is a structural schematic diagram of Embodiment 1 of a bell jar type gas flowmeter verification device of the present invention;

Fig. 2 is a structural schematic diagram of Embodiment 2 of the bell jar type gas flowmeter verification device of the present invention.

In the figure 1. Large bell jar type gas flowmeter verification device; 2. Large bell jar type gas flowmeter verification device; 3. Computer control system; 4. Intake pipeline; 5. Back pressure pipeline; 6. Control valve; 7. Telescopic pipe; 8. Sink; 9. Bell jar; 10. Straight pipe; 11. Pneumatic switch valve; 12. Connecting pipe; 13. Encoder; 14. Limit switch; 15. Photoelectric switch; 16. Pneumatic switch Valve 17, rectifying device.

Detailed ways

The bell-jar type gas flowmeter verification device of the present utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Embodiment one:

As shown in the figure, the bell-jar type gas flowmeter verification device of the present utility model includes a bell-type gas flow standard device, a measured flow meter, and a computer control system 3. The bell-type gas flow standard device has a bell-type gas flow standard device. The pressure sensor P _A and temperature sensor T _A in the flow standard device and the temperature sensor T _A+ located outside the bell type gas flow standard device, the signal output terminals of the pressure sensor P _A and temperature sensors T _A and T _A+ are connected to the computer control system 3; the front ends of multiple measured flowmeters are connected to an intake pipeline 4, and the intake pipeline 4 extends into the bell-type gas flow standard device, and the front ends of each measured flowmeter are A pressure sensor P _B and a temperature sensor TB located on the intake pipeline 4 are provided, and the pulse signal output terminals of the pressure sensor P _B , temperature sensor T _{B and} the measured flow meter are all connected to the signal acquisition terminal of the computer control system 3; The back end of the flowmeter is connected with a back pressure pipeline 5, and the back pressure pipeline 5 has a control valve 6, the said control valve 6 is an electric control valve; the signal input end of the control valve 6 is connected with the signal output of the computer control system 3 end, the opening of the valve is controlled by a computer; there is also an expansion tube 7 between the measured flow meter and the control valve 6, and the expansion tube 7 adopts a QSS type pneumatic expansion device with the same diameter as the pipeline, which is used to tighten the measured flow rate. Table, the part in contact with the medium is made of stainless steel, and the stainless steel material is 1Cr18Ni9Ti; said air intake line 4 has a pneumatic switch valve 11, and the signal output end of the pneumatic switch valve 11 is connected to the signal acquisition end of the computer control system.

Further, said measured flow meters are set to more than two, they can be connected to the intake pipeline 4 as a group in series, and can also be connected in parallel to the intake pipeline 4 respectively, of course, each group connected in series The flow meters to be measured can also be connected in parallel on the intake pipeline 4 in groups.

When multiple measured flow meters are connected in parallel to the intake pipeline 4 , each measured flow meter has a straight pipe 10 at its front end, and the pressure sensor P _B and temperature sensor _TB are located on the straight pipe 10 . When multiple measured flowmeters are connected in series to the intake pipeline 4 as a group or each group of series-connected measured flowmeters are connected in parallel to the intake pipeline 4 respectively, a measured flowmeter at the front end There is a section of straight pipe 10 at the front end, the pressure sensor P _B and the temperature sensor T _B are located on the straight pipe 10, and the front end of each measured flow meter located at the rear is provided with a connecting pipe 12 with a rectification device 17, and the connecting pipe 12 is installed There are pressure sensor PC and temperature sensor T _C , pressure sensor P _B , _{PC ,} temperature sensor T _B , T _C and pulse signal output terminals of each measured flow meter are connected to the signal acquisition terminal of computer control system 3 .

Furthermore, the bell-jar type gas flow standard device of the present utility model is an existing high-precision bell-type gas flow standard device, and it comprises a water tank 8 and a bell jar 9 buckled in the water tank, and the water in the water tank makes the bell jar and Air is sealed between the water surfaces, and the air intake pipeline 4 passes through the water surface and extends into the bell jar 8. The bell jar type gas flow standard device is also provided with an encoder 13, a limit switch 14 and a photoelectric switch cooperating with the encoder. 15. The signal from the encoder 13 is input into the computer control system to accurately calculate the descending distance of the bell jar.

Embodiment two:

As shown in Figure 2, the bell jar type gas flowmeter verification device of the present utility model comprises a big bell jar type gas flow standard device 1 and a small bell jar type gas flow standard device 2, the big bell jar type gas flow standard device 2 1 has the same structure as the small bell-type gas flow standard device 2, the capacity of the large bell-type gas flow standard device 1 is 2000L; the capacity of the small bell-type gas flow standard device 2 is 200L, and the small bell-type gas flow standard Device 2 has a pressure sensor P _A2 , a bell top temperature sensor T _A2+ and a bell bottom temperature sensor T _A2 , and a large bell type gas flow standard device has a pressure sensor P _A1 , a bell top temperature sensor T _A1+ and a bell Bottom temperature sensor T _A1 , pressure sensor P _{A1 and temperature sensor T A1 located in the large bell-type gas flow standard device, pressure sensor P A2 and temperature sensor T A2 in the small} bell-type gas flow standard device and located in the large bell-type gas flow standard device The signals of the temperature sensor T _A1+ outside the bell-type gas flow standard device 1 and the temperature sensor T _A2+ outside the small bell-type gas flow standard device 2 are connected to the signal acquisition terminal of the computer control system through the temperature and pressure transmitters; There is a section of straight pipe 10 at the front end of the measured flowmeter at the front end, and there is a pressure sensor P _B and a temperature sensor T _B on the straight pipe 10. The front end of each measured flow meter located at the rear is provided with a connecting pipe with a rectification device 17 12. The connecting pipe 12 is equipped with a pressure sensor PC and a temperature sensor T _C , the pressure sensors P _B , _PC , temperature sensors T _B , T _C and the pulse signal output terminals of each _measured flow meter are connected to the computer control system 3 There are two sets of pneumatic switching valves on the air intake pipeline 4, and the computer control system can automatically select the bell type gas flow standard device and the pipeline caliber by controlling the two sets of pneumatic valves according to the input parameters of the flowmeter to be tested; The small bell-type gas flow standard device 2 is used to verify the small flow rate of the flowmeter [(0.1-5)m ³ /h], and the large bell-type gas flow standard device 1 is used to verify the large flow rate of the flowmeter [(5- 120) m ³ /h]; by increasing the thickness of the bell jar wall, the pressure in the bell jar can be increased (the bell jar pressure of 200L small bell jar type gas flow standard device 2 is 2.5kPa, the 2000L big bell jar type gas flow rate The bell pressure of the standard device 1 is 4.7kPa), so the large bell-type gas flow standard device 1 and the small bell-type gas flow standard device 2 are used for verification in series, and two flowmeters of the same type can be verified each time. The rectification device installed between the two flowmeters to be tested can eliminate the air flow pulsation between the two flowmeters to be tested, make the airflow pressure stable, and ensure that the pressure loss is less when the gas flows through, which can meet the verification requirements of the two flowmeters The required pressure; the device can be used to verify various gas volumetric flowmeters with a caliber of DN5-DN80, and the range of the verification can detect (0.1-120) m ³ /h, and the device expansion uncertainty is Ur= 0.2%, (k=2).

Its working process is as follows:

Before the verification of the flowmeter, the computer control system automatically selects the bell jar type gas flow standard device and the pipeline caliber by controlling the pneumatic valve 11 according to the input parameters of the tested flowmeter. When the verification starts, the bell jar 9 is lowered and the bell jar 9 is discharged. The gas is controlled by the air intake line 4, selects the pneumatic valve 11 and the pneumatic valve 16 and opens them, and through the pneumatic valve 11, the gas enters a flow meter at the front end through the straight pipe 10, and then passes through the connecting pipe 12 (with a rectifying device 17 ) enters the flowmeter to be tested at the back, and finally discharges into the air after adjusting the flow rate through the electric control valve 6.

The valve is closed, and the system completes a verification. At the same time, after automatically selecting the bell-jar gas flow standard device and pipeline caliber, the computer control system will collect the corresponding bell-jar flow through the temperature and pressure sensor and temperature and pressure transmitter. and the temperature and pressure in the pipeline of each flowmeter to be tested, and compensate the temperature and pressure change after comparison and processing by the computer. The temperature and pressure change compensation system in each flowmeter pipeline and the corresponding bell jar is independent. Each verification is to collect the temperature and pressure in the corresponding bell-type gas flow standard device and the pipeline of the tested flowmeter, and then perform temperature and pressure change compensation to determine the accuracy of the tested flowmeter; and collect the selected bell The data of the drop of the hood and the flow data of the flowmeters connected in series are recorded, and the time of these flows is recorded, and the calculation program is used to automatically calculate, display and output the verification results, and print them out.

Claims (10)

1. a bell-jar type gas flow meter verification device, comprising a bell-jar type gas flow standard device, a measured flow meter, a computer control system (3), is characterized in that: said bell-jar type gas flow standard device has a The pressure sensor P _A and temperature sensor T _A in the bell type gas flow standard device and the temperature sensor T _A+ outside the bell type gas flow standard device, the signal output of the pressure sensor P _A and temperature sensor T _A, T _A+ The terminal is connected to the signal acquisition terminal of the computer control system; the front ends of multiple measured flowmeters are connected to an air inlet pipeline (4), and the air inlet pipeline (4) extends into the bell type gas flow standard device , the front end of each of the measured flow meters is provided with a pressure sensor P _B and a temperature sensor T _{B on the intake pipeline (4), and the pressure sensor P B ,} the temperature sensor T _B and the measured flow meter The pulse signal output ends are all connected to the signal acquisition end of the computer control system (3). 2. The bell type gas flowmeter verification device according to claim 1, characterized in that: said plurality of measured flowmeters are connected in series to the intake pipeline (4). 3. The bell jar type gas flowmeter verification device according to claim 2, characterized in that: said plurality of series-connected measured flowmeters are connected in parallel on the intake pipeline (4). 4. The bell jar type gas flowmeter verification device according to claim 1, characterized in that: each of the measured flowmeters is connected in parallel to the intake pipeline (4). 5. The bell type gas flowmeter verification device according to claim 2, characterized in that: the back end of the measured flowmeter is connected with a back pressure pipeline (5), and there is a control on the back pressure pipeline (5). A valve (6), the signal input end of the control valve (6) is connected to the signal output end of the computer control system (3). 6. The bell-jar type gas flowmeter verification device according to claim 1, characterized in that: said air intake line (4) has a pneumatic on-off valve (11), and the signal output end of the pneumatic on-off valve (11) is connected to The signal acquisition terminal of the computer control system. 7. according to the described bell type gas flowmeter verification device of claim 4, it is characterized in that: the front end of described measured flowmeter all has a section straight pipe (10), and pressure sensor P _B and temperature sensor T _B are positioned at straight pipe. on the tube (10). 8. according to the described bell-jar type gas flowmeter verification device of claim 3, it is characterized in that: the front end that is positioned at the front end of a measured flowmeter has a section of straight pipe (10), pressure sensor P _B and temperature sensor T _B is located on the straight pipe (10), and the front end of each measured flow meter located at the rear is provided with a connecting pipe (12) with a rectification device (17), and a pressure sensor _PC and a temperature sensor are installed on the connecting pipe (12) T _C , pressure sensors P _B , PC , temperature sensors _TB , T _C and pulse signal output terminals of each measured flow meter are connected to the signal acquisition terminal of the computer control system (3 ₎ . 9. The bell jar type gas flow meter verification device according to claim 1, characterized in that: a telescopic tube (7) is also arranged between the measured flow meter and the control valve (6). 10. According to the bell-jar type gas flow meter verification device according to any one of claims 1-9, it is characterized in that: the bell-jar type gas flow standard device is set as a large bell-type gas flow standard device and a small bell-type gas flow standard device. Gas flow standard device, the large bell-type gas flow standard device is used to verify the large flow of the flowmeter, and the small bell-type gas flow standard device is used to verify the small flow of the flowmeter, located between the large bell-type gas flow standard device and the small The signal output terminals of the pressure sensor P _A and temperature sensor T _A in the bell-jar type gas flow standard device and the temperature sensor T _A+ located outside the large bell-jar gas flow standard device and the small bell-jar gas flow standard device are all connected to the computer The signal acquisition end of the control system; there are two groups of pneumatic switching valves on the air intake pipeline (4), and the computer control system can automatically select the bell-type gas flow standard by controlling the two groups of pneumatic valves according to the input parameters of the tested flow meter. Device and pipe diameter.