Contents:
- Magnetic Flow Meter
- Principle of Magnetic Flow Meter
- Magnetic Flow Meter Diagram
- How Magnetic Flow Meter Works
- Wet Gas Meter
- Wet Gas Flow Meter
- Gas Flow Measurement Techniques
Principle of Magnetic Flow Meter:
It consists of a non-magnetic pipe enclosed by an electromagnet (which generates a magnetic field) as shown in Fig. Two metal electrodes are mounted flush with the inner wall of the pipe. A fluid is flows through non-magnetic pipe.
In this meter, the fluid flows through a magnetic flux and generates a voltage which is directly proportional to the velocity of the fluid through the meter. The use of this meter is limited to fluids having some electrical conductivity, such as liquid metal coolants. They are now developed to handle liquids having poor electrical conductivity, like water. Special features of the meter include – a very negligible drop in pressure and ability to handle fluids containing a high percentage of solids.
Quantity Meter:
These types of meters measure directly total quantity of fluid which has passed in a given time. The quantity of fluid divided by time of passage gives the average flow rate. The wet and dry gas meters are examples of flow meters falling in this class for the measurements of the flow of gas through a pipe.
A wet gas meter consists of a segmented cylindrical rotor in four parts. A narrow slot is provided in the axis of the rotor for gas inlet in the meter and a narrow slot is parallel to axis of rotor is provided for gas discharge at the outer edge of rotor. The rotor is immersed in water and suitable liquid in which the gas is insoluble. Gas is introduced into hollow axis and bubbles into the segment by displacing the liquid.
Gas fills the segment, and causes the segment to rotate, expelling an equal volume of gas from another segment. One complete revolution of the rotor indicates the volume swept which is equal to volume of four segments. The volumetric flow rate is obtained by measuring the number of rotations per minute.