Selection principle of flowmeter in industrial production 2

Various flowmeter selection characteristics

1. Mass flowmeter

For the material

Suitable for a variety of media

The principle of structure

Mass flow meter based on coriolis force, inside the sensor has two parallel flow pipe, is equipped with central drive coil, at both ends is equipped with detecting coil, transmitter provides the excitation voltage to the drive coil, vibration tube for reciprocating cycle, the vibration of the industrial process of fluid flowing through the sensor, will be produced in the vibration tube coriolis force effect, make the two root vibration control torsional vibration, installed in a vibration at the ends of the pipe line will produce phase difference of two groups of signals, the two signals of phase and is proportional to the mass flow rate of fluid flowing through the sensor.The computer calculates the mass flow through the vibrating tube.When different media flow through the sensor, the main vibration frequency of the vibrating tube is different.Platinum resistance mounted on the vibrating tube of the sensor can indirectly measure the temperature of the medium.

Measuring characteristics

The mass flowmeter directly measures the mass flow of the medium through the flowmeter, and also measures the density of the medium and indirectly measures the temperature of the medium.

Matters needing attention

1. When measuring gas, some models are only suitable for the measurement of air and other similar gases, while some can be used for natural gas and steam.Want to consult with manufacturer in detail.

2. In case of gas pinch, gasification or two-phase flow in the measuring medium, the transmitter will give an alarm and display. In case of serious condition, the sensor will stop working.

2. Orifice flowmeter

For the material

Widely used in gas, vapor and liquid flow measurement.

1. It is more suitable for measuring saturated steam, superheated steam, gas, cooling water and other dirty fluids.

   

2. It is easier to adapt to the flow measurement of high-temperature and high-pressure fluids.

The principle of structure

LG orifice flowmeter, also known as differential pressure flowmeter, is composed of primary detector (throttle) and secondary device (differential pressure transmitter and flow indicator).Adopt uniform pressure ring, one - body structure.

   

Measuring characteristics

The structure of throttling device is easy to duplicate, simple, firm, stable and reliable performance, long service life and low price.

A type of orifice plate installation is easier, without pressure tube, can be directly connected to the differential pressure transmitter and pressure transmitter.

   

Intelligent continuous work for 5 years without adjustment

Matters needing attention

The orifice flowmeter shall be installed with a measuring tube, which shall maintain at least the first 10DN and last 5DN straight pipe sections to improve the measurement accuracy.

   

The single-phase fluid state must always be maintained in the pressure line.When the fluid being measured is a gas, all the pressure channels (including the pressure chamber of the differential pressure gauge) are filled with gas phase.When the fluid being measured is liquid, all the liquid phase in the pressure tube must not have bubbles.This should be installed in the lowest point of the pressure pipeline drainage valve or in the highest point of the installation of exhaust valve