1、 Usage characteristics

Intelligent vortex flowmeter is mainly used for flow measurement of industrial pipeline medium fluids, such as gas, liquid, steam and other media. Its characteristics are small pressure loss, large range, high accuracy, and almost unaffected by parameters such as fluid density, pressure, temperature, viscosity, etc. when measuring volumetric flow rate under working conditions. No movable mechanical parts, therefore high reliability and low maintenance. The instrument parameters can remain stable for a long time. This instrument uses piezoelectric stress sensors with high reliability and can operate within a temperature range of -25 ℃ to+320 ℃. It has both analog standard signals and digital pulse signal outputs, making it easy to use in conjunction with digital systems such as computers. It is a relatively advanced and ideal flow meter.

2、 Main technical parameters (see Table 1)

2. Liquid and working condition gas flow range (see Table 2)

3、 Structure and dimensions of vortex street sensors

1. Outline dimension diagram

2. External dimensions

All data in the above table is based solely on standard sensors.

For sensors with smaller diameters, the size of the meter head may be larger than the size of the sensor.

3. Other pressure levels not listed may have different sizes.

4、 The usage method of vortex street

1. Function:

1) Frequency measurement with accuracy ranging from 0.8 to 3KHz;

2) 4-20mA output;

3) Upper and lower limit alarm output, the monitored parameters, high and low alarms, and level output methods can be set as needed;

4) Three 12 bit AD inputs (temperature, pressure, battery voltage);

5) Can output at a frequency of 0-1000Hz;

6) Accumulated traffic can be recorded.

7) The average power consumption of the whole machine is 450 μ A.

4、 Wiring diagram:

1) Jumper version

2) Dial up version

3) The meaning of terminal blocks is as follows:

4) Jumper (DIP) diagram

5) Wiring diagram

5、 Installation precautions

Vortex flow meters are sensitive to flow velocity distribution distortion, rotational flow, and flow pulsation in pipelines. Therefore, the installation conditions of pipelines on site should be fully taken into account, and the requirements of the manufacturer's instructions should be followed. Vortex flowmeter can be installed indoors or outdoors. If installed in underground wells, there is a possibility of flooding, and submersible sensors should be selected. Sensors can be installed horizontally, vertically, or obliquely on pipelines, but when measuring liquids and gases, attention should be paid to the installation position to prevent interference from bubbles and droplets, as shown in Figure 1.

The vortex flowmeter must ensure that the upstream and downstream straight pipe sections have the necessary length, as shown in Figure 2. There are differences in data among various sources, which may be due to the fact that vortex generators have not yet been standardized, and the impact of differences in shape and size remains to be verified; The experimental research on the necessary length of straight pipe sections for various types of flow blocking components is still insufficient, that is, it is not yet mature. Compared with throttling differential pressure flow meters, this work is still in its initial stage.

Figure 2 Requirements for downstream straight pipe length of vortex flowmeter

(a) A 90 ° elbow; (b) Concentric expansion tube; (c) Concentric contraction fully open valve; (d) Two 90 ° elbows on different planes; (e) Half open regulating valve; (f) Two 90 ° elbows on the same plane

The connection between the sensor and the pipeline is shown in Figure 3. Pay attention to the following issues when connecting with pipelines.

1) The inner diameter D of the upstream and downstream piping is the same as the inner diameter D 'of the sensor, and the difference satisfies the following conditions:

0.95D ≤ D ′ ≤ 1.1D.

2) The piping should be concentric with the sensor, and the coaxiality should not be less than 0.05D '

3) The sealing gasket cannot protrude into the pipeline, and its inner diameter can be 1-2mm larger than the inner diameter of the sensor. If it is necessary to cut off the flow for inspection and cleaning of the sensor, a bypass pipeline should be set up as shown in Figure 4.

5) The impact of external vibrations on vortex flowmeters should be addressed as a prominent issue in the on-site installation of vortex flowmeters. Firstly, when selecting the installation location for sensors, try to avoid vibration sources as much as possible. Secondly, elastic hoses can be used for connection, which can be considered for small diameters. Thirdly, installing pipeline supports is an effective vibration reduction method, as shown in Figure 5.

Electrical installation should pay attention to using shielded cables or low-noise cables to connect sensors and converters, and the distance should not exceed the specifications in the user manual. When wiring, it should be kept away from high-power power lines and protected with separate metal sleeves as much as possible. The principle of "one point grounding" should be followed, and the grounding resistance should be less than 10 Ω. Both integral and separated types should be grounded on the sensor side, and the grounding point of the converter housing should be "same ground" as the sensor. The installation position with temperature and pressure compensation is shown in Figure 6.

6、 Precautions for installation and use of explosion-proof products

1. The product casing is equipped with wiring terminals, and users should ensure reliable grounding when using the product, but it should not be shared with the protective grounding of the high-voltage system.

2. There should be no harmful gases present at the installation site that can corrode aluminum alloys.

3. On site installation and maintenance must comply with the warning message 'Do not open the lid when there is explosive gas'.

4. The maximum temperature of the explosion-proof enclosure shall not exceed 130 ℃

5. Maintenance and battery replacement must be carried out in a safe place; Maintenance can only be carried out after confirming the absence of flammable gases at the installation site.

6. Users must comply with both GB3836.1-2010 and GB3836.2-2010 explosion-proof standards when installing, using, and maintaining the product

The relevant provisions of GB50058-92 "Design Code for Electrical Installations in Explosion proof and Fire Hazardous Environments" and "Electrical Safety Regulations for Explosive Hazardous Areas of the People's Republic of China" shall be followed.

7. When using an external power source or external signal, the cable should be a rubber cable with an outer diameter of φ 8~φ 8.5. If no external power source or external signal is used, the cable outlet hole must be sealed tightly with a blind plate.

8. Explosion proof type is used in hazardous areas below Zone 1 for Class II, Class C, T4 combustible gases.

7、 Precautions for use

(1) On site installation and maintenance must comply with the warning message "Do not open the cover of explosive gas objects", and turn off the external power before opening the cover.

(2) Inspection before power on and current flow after on-site installation

a. The flanges, valves, pressure measuring holes, temperature measuring holes, and connections on the supervisor and bypass pipes should have no leakage phenomenon;

b. Does the vibration of the pipeline comply with the specifications in the manual;

c. Is the sensor installed correctly? Are the electrical connections of each part good?

(3) Power on static debugging

When the power is not flowing, the converter should have no output, the instantaneous flow indication should be zero, and the cumulative flow should not change. Otherwise, first check whether interference signals are introduced due to signal line shielding or poor grounding, or strong pipeline vibration. If it is confirmed that the above reason is not the case, the potentiometer inside the converter can be adjusted to reduce the amplifier gain or increase the triggering level of the shaping circuit until the output is zero.

8、 Selection