Industry new

Description of the difference between electromagnetic flowmeter and wedge flowmeter

The conductivity of the electromagnetic flowmeter usually does not cause an error due to the change of the conductivity of the medium. However, regarding the positive converter output impedance, the conductivity of the measured medium has an upper limit min, which cannot be lower than the upper limit. .

The wedge flowmeter connection method is divided into: welded installation type and flange installation type. In the case of small-caliber on-site flow measurement, it is advisable to adopt a flange connection type, and absolutely some large-diameter pressures are relatively large, and it is recommended to adopt a welding connection type.

In fact, orifice flowmeter, V-cone flowmeter, powerbar flowmeter, average velocity flowmeter, wedge flowmeter, and elbow flowmeter are very common. The orifice flowmeter is also representative of differential pressure flowmeter.
The conductivity of the measured medium is too large. For example, when the conductivity exceeds 10-1 (S/cm), the flow signal will be decreased, and the guiding value will be changed, that is, the guiding flow value is smaller than the actual flow value. This is because in the electromagnetic fluid transmitter, the magnetic field is finite, and the measured conductive liquid flows through the finite magnetic field, and the ability to induce the electromotive force e. Therefore, the induced electromotive force e representing the flow signal is the consequence of the magnetic field of the magnetic field cutting the magnetic field lines, and the conductive liquids outside the magnetic field do not make any contribution to e. On the contrary, since they are also connected to the two electrodes, an external circuit is formed. When the transmitter is connected to the converter, the external circuit is connected in parallel with the output impedance of the converter to become the load of the transmitter. When the conductivity of the measured medium is large, the resistance of the external circuit is small, no matter how high the output impedance of the converter is, the consequences of the parallel connection will depend on the external circuit of the liquid in this department, thereby reducing the transmitter and conversion. Transmission accuracy between the devices.

1. For the characteristics of petroleum, after the field installation of the wedge flowmeter, first review each valve, whether the pressure guiding pipe and the union can be connected.

2. Review whether the secondary valve and the drain valve can be closed, and whether the equalization valve can be closed.

3. Open the valve a little and review the pressure guiding tube. There is a leak at the joint and the valve. If it does not leak, close all the valves.

4. Close the drain valve after the break-up, close the drain valve after the sewage is discharged

5. Loosen the differential pressure chamber plug and remove the air from it.

The time when the wedge flowmeter is used on site is used in an invasive site, so it is necessary to do a good job of anti-corrosion. The detailed method can take the corresponding throttle material, and the second is to use the method of flange isolation and pressure to cover the differential pressure transmitter and extend the service life. In fact, you should be able to invent carefully, such a debugging step can be extended to the scale of all differential pressure flowmeters, such as standard throttling installation: orifice flowmeter, nozzle flowmeter, venturi flowmeter, non-standard Throttle installation: V-cone flowmeter, elbow flowmeter, Powerbar flowmeter and the wedge flowmeter we talked about today. The differential pressure flowmeter is the same in principle, so such installation and debugging steps can also be promoted.

PREVIOUS：The principle of the principle of the electroNEXT：Comparison of integrated orifice flowmeter an