Custom Search

Wednesday, March 14, 2012

Different level measuring systems : A Comparison






ADVANTAGES/DISADVANTAGES OF LEVEL MEASURING SYSTEMS:

Here below is a table showing the comparison of different level measuring systems I have posted before. The table gives the advantages and disadvantages of different methods along with the principle they use.


PRINCIPLE

SYSTEM

CHARACTERISTICS

ADVANTAGE

DISADVANTAGE








SIGHT

DIPSTICK

Simple, cheap, instant

Need to remove to read

SIGHT GLASS

Cheap, fairly foolproof, pressure up to 700 Mpa and 300oC

Need to careful handling, brittle.


TAPE/FLOAT

Cheap, can be used with corrosive liquids, but opening for tape.

Low pressure/ atmospheric only.
Can Stick.

POTENTIOMETER FLOAT

Voltage output as above

Stiction

MAGNETIC

As above

Stiction



DISPLACERS

SPRING BALANCE

Can be used for interfaces, limited range.

Expensive

TORQUE  TUBE

Most displacer transmitters use this, accurate but limited range.

Limited range.



PRESSURE

PRESSURE GAUGE

Cheap, open and closed tank.

Not available readily in low range in H2O.

BUBBLER METHOD

Can be used for slurries, or corrosive mixtures.

Requires air supply.

WEIGHT

LOAD CELLS

Accurate non-contact method.

Need frequent recalibration.


ELECTRICAL

CONDUCTIVITY

Rugged, requires little maintenance.

Limited to conductive liquids.

RESISTANCE

Rugged, requires little maintenance.

First few inches not accurate.

CAPACITIVE

Rugged and accurate.

Tank must be metal if only probe is used.

ULTRASONIC

ECHO TYPE

Non-contact

High pressurize wont work, expensive.

RADIATION

ABSORPTION

Non-intrusive.

Expensive, not accurate, hazardous source.

THERMAL

THERMISTOR

New method, cost reasonable.

On/Off only


Article Source: Level Measurement by N. Asyiddin  

Read more...

Basics of Instrumentation & Control


To view more posts on BASICS : CLICK HERE

Pressure


To view more posts on PRESSURE : CLICK HERE

Flow


To view more posts on FLOW : CLICK HERE

Level


To view more posts on LEVEL : CLICK HERE

Temperature


To view more posts on TEMPERATURE : CLICK HERE
Related Posts Plugin for WordPress, Blogger...

About This Blog

Hai friends…welcome to my blog. This blog is exclusively for instrumentation engineering students which will provide sources for their reference and studies. As you all know Instrumentation is now a fast emerging and developing field in Engineering. This blog has different categories like PLC, SCADA, DCS, Sensors and Transducers, Computer control of process, Industrial Instrumentation, etc.

This blog will also provide an exclusive ‘ASK ME’ section where you can make any queries and share your ideas about instrumentation. The solution for your queries will be given to you by mail from best of my knowledge and reference.

So I wish this blog may be very useful for your studies and reference.

Online Queries


About Me

Keep In Touch

Follow Me!

Popular Posts

  © Blogger templates The Professional Template by Ourblogtemplates.com 2008

Back to TOP