Level Measurement and Control Principles

A lot of good info at this site:

http://www.drexelbrook.com/products/CLMS.cfm

The information there are not detailed, any other?

I need more information from you to help. Are you looking for an application guide? Or perhaps theory of operation? Homework help? What.

Pl. click on the below link to know more about your requirement.

www.omega.com/literature/transactions/Transactions_Vol_IV.pdf

Regards,

Kamit patel

Dear tega4tj, as Sparkstation would say :

Also if you could provide as requested by Bricktop then you will find answers here.

Sparkstation I hope you don't mind me borrowing some of your animation (if it makes you feel any better it took me ages to do this - it is a slow day at the office )

Regards

Mr. W.A Snow

It's not a mockery in no way, but some devices at toilet room wouldn't be bad for studying of the level measurment and their control principles.

Real basic primer on level senders with electrical transmission:

There are two types with various means of sensing - continual, which reads from bottom to top of tank, and point, which only tells you when the level hits the point where the sensor is located. Obviously, a continual can be used as a point sensor, by only acknowledging a set readout point, (say 10 ma on a 4-20ma transmitter, where 10 ma is 62.5% of the level sensing distance) but a point sensor can not be used as a continual sensor. Stability in tanks with aggressive inputs or mixers are the reason for so many variations, but all have various success and failures in tanks which have wildly fluctuating levels. Here you have to experiment to determine which is best in your case.

Examples I have used:

1. Float type - mechanical - point level control - a float on a pivoting arm mounted in the tank wall is raised by increasing fluid level and trips a micro switch. Or, the float is on a vertical rod and when it reaches a set point (top), it trips a switch.

2. Ultrasonic - electronic - continual level control - like a radar, sound waves are transmitted and received - sensor mounts on top and points toward bottom of tank - time of travel correlates to fluid level

3. Capacitive - electronic - point level control or continual - as the name implies, as the capacitance of the sensed area changes from fluid entry or exit, the sender is tripped. The sensor can be horizontal and only pick up a point, or vertical and sense over the length of the probe making it continual.

4. Tuning Fork - electronic - point level control - very similar to capacitive - a vibrating fork will change frequency when the medium around it changes. Mounted horizontal in tank wall to sense when fluid reaches it.

5. Guided wave - electronic - continual level - basically an ultrasonic that travels over a metal rod conduit. Go to the manufacturers for the propaganda as to why this is better than the sensor mounted on the tank head. I know this creates a problem when used in slope bottom tanks. Bend the rod to follow the slope, and you create a very non-linear response area. Had to do this once on customers directives and will never try it again. Glad I wasn't the poor programmer who had to try to find a mathematical solution to track this output.

6. Magnetostrictive - electronic - continual level - a magnetic ball that floats travels up/down a rod with a sensing circuit enclosed

7. Differential pressure - electronic - continual level - pressure sensors are mounted on tank top and bottom - difference in pressure correlates to fluid level.

8. Pressure - electronic - continual level - same as differential, but minus the top mount sensor. Use this if the tank will never pressurize, as it saves the cost of one sensor.

9. Radioactive - I've never tried this one, but it can read through some thick tank walls. Basically like the tools I used in the analysis of rock formations in oil wells. - the backscatter of gamma rays or nuetrons (I've never checked which they use in these sensors), relates directly to the density of the matter they are directed into. Returning radiation is sensed to determine density. Higher density means fluid not air is in the path of the readiation.

10 Million others - many variations and combinations exist based on the above principles.

www.k-tek.com for liquid and solids laser, radar ,ultrasonic ,plumb bob , paddle, vibrating fork,

rf switch ......

I am really overwhelmed with all your positive response, precisely speaking, PHYS, JAMESAMKIFFER AND KAMITAPATEL has offered me vital informations with what i need. Ones again i want to say thank u all for ur contributions.