Vortex Flow Meter

The vortex shedding flow meter, commonly known as vortex flow meter. a non stream  lined obstruction known as a shedder bar or buff body is placed across the middle of the flow stream.  As the fluid stream in the pipe hits this obstacle it must separate to pass around it with fluid layers nearer the surface of the moving slower than those further away. As a result when these fluid layers recombine after passing the bar, vortices are generated and shed alternately from either side of shedder bar.

The frequency of generated vortices is usually detected using sensors integrated both sides of the shedder bar. Pressure and capacitance type sensors are commonly used.

Level Troll

Level troll is an instrument used to measure level of closed tanks. Instrument contain a displacer, dipped in a vessel. The displacer will move up and down with liquid level in the vessel / tank.

This instrument works under the Archimedes principle. the liquid in the vessel will act an upward force to the displacer (Buoyancy Force). this force will help to move upward. Buoyancy force depends up on density of liquid. 

Buoyancy Force= Volume of displacer X Density of liquid

A tape is attached to the displacer to a torque arm. Measured torque will covert into electric form (4 to 20 mA).

Video

Calibration

Two types of calibrations

1. Wet calibration
2. Dry calibration

Electromagnetic Relay

A relay is an electrical switch that uses an electromagnet to move the switch from the OFF to ON position.  It takes a relatively small amount of power to turn on. Both AC and DC relays are used in industrial applications. Contact between the Common terminal and NC terminal will keep relay if power is applied to the coil. common terminal make contact with NO when energies the coil. SPDT and DPDT relays are commonly used in industries.

Simple Level Measurement

 Sight Glass

Sight glass is direct method to measure level. Only local indication is possible by this method.

If a scale is placed near the sight glass we can measure the level of  a tank. Isolation valves should place in between the sight glass and tank, in both ends.
Isolation valves will help to isolate both ends of the tank(connected to sight glass) during maintenance of the  sight glass (replacement). If the glass is broken leakage of the fluid in the tank can be isolated by the isolation valves.

Float and Tape

Industrial Instrumentation

The progress of an industry always depends on instruments. A much wider use of instruments for measurement and control has become an essential feature of measuring process operation. Instruments have provided to increase the quality and quantity of products.