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Level Transmitter

07/04/2016 7:27 AM

Dear Friends,

I have a 6 meter height tank which having liquor(liquid) of temp range 1200C to 1500C. Its density also varies 1.0 to 1.2. what types level transmitter I can use for level measurement. please give me best solution.

enjoy full day.

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#1

Re: Level Transmitter

07/04/2016 9:48 AM

Before knowing what type of liquid and what the space above the liquid contains and at what pressure, and what the materials of construction of the tank are and the currently-spare connections available on it, the answer is "any of them", because the situation has not been fully specified. So here are some pointers:

  • Differential pressure is out, because the density varies.
  • If the temperature and the composition of the liquid varies, do not use capacitance.
  • If the space above the liquid is a partial or full vacuum, do not use ultrasonic.
  • If the tank is agitated or there are issues with foaming, do not use ultrasonic or capacitance, or radar.
  • If there are no spare flanges available on the top of the tank, then radar is out, however, if the top of the tank is open, and the reason for doing that on a tank at those temperatures is abstruse, then radar might become available as a technique. However, if there are floating insulating materials on the top of the liquid, then forget it.
  • If there is a spare flange on the bottom, then it might be possible to use a magnetic follower, however if the liquid contains caking solids (sewage sludge and strawberry jam are typical problem fluids) then forget it. Lagging the instrument to prevent heat loss and accidental contact with it might be an issue.
  • Radionics requires a licence to use radioactive materials, which might not be compatible with the local environment and regulations.
  • Weigh cells can be used, of course: one on each support leg is typical. Then if the tank has no legs, which is unlikely for a 6m high tank containing high value product at high temperature, forget it.

Whatever is selected needs to be compatible with the properties of the wetting fluid, which may be a problem with some plastics and some metals.

Please advise suppliers' recommendations as no doubt this has been discussed with several over the telephone!

The <...best solution...> is therefore, without doubt, to consult a qualified Instrument Engineer locally, as the forum cannot see the proposed installation.

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#9
In reply to #1

Re: Level Transmitter

07/07/2016 5:15 AM

TANK HAVING 3 METER DIA. THERE ARE NO PRESSURE AND VACUUM IN THE TANK. IT IS OPEN TANK HAVING VAPOR. THERE IS EXTRA FLANGE ON TOP OF TANK CENTER . AGITATOR IS NOT PRESENT. I TRIED RADAR TYPE TRANSMITTER BUT DUE TO HIGH TEMPERATURE , RADAR GIVEN ALARM AND VALUE GOING TO HANG. NOW WHAT I CAN DO.

<THANKS >

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#10
In reply to #9

Re: Level Transmitter

07/07/2016 6:01 AM

Start by stopping THE SHOUTING. It's rude, uncalled for, and switches readers off. No-one has any obligation to help, and the responses that are received to posts are simply gestures of goodwill from the anonymous.

Many of the questions needing answers to address the issue, for example the nature of the fluids and the configuration of the tank, have been ignored. So, again:

  • Please advise suppliers' recommendations as no doubt this has been discussed with several over the telephone!
  • The <...best solution...> is therefore, without doubt, to consult a qualified Instrument Engineer locally, as the forum cannot see the proposed installation.

Good luck.

<unsubscribes>

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#11
In reply to #10

Re: Level Transmitter

07/07/2016 5:43 PM

Yup! Other my girlfriend, who else would know?

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#13
In reply to #9

Re: Level Transmitter

07/27/2016 2:58 PM

Were you using a guided-wave radar, or non-contact radar? Vapors can often cause problems for non-contact radar where the radio signal must pass through the vapor space (and back again!) to read liquid level. Guided-wave radar level transmitters tend to fare better because the waveguide cable/probe carries a stronger signal to and from the liquid interface.

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#12
In reply to #1

Re: Level Transmitter

07/27/2016 2:55 PM

If the product composition is consistent over time, it may be possible to build a temperature-compensated DP level system. A look-up table reads predicted density values as a function of temperature, which then is used to compute level (height) from hydrostatic pressure.

This sounds like an interesting application -- it would be nice if the OP provided some more information. One pertinent question that springs to mind is "how accurate must this level measurement be?". If it exists only to prevent overflowing and empty conditions, straight DP level might be good enough. For that matter, a set of level switches might do just as well.

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#2

Re: Level Transmitter

07/04/2016 10:00 AM

Well unless this vessel is under pressure, this liquid is not water at the temperatures you claim. To make a safe suggestion on how to measure the level of a liquid hotter than boiling water requires knowing the nature of this liquid. There will be a completely different set of hazard concerns measuring R-12 refrigerant, glycerine, ink, Methyl iodide or molasses.

I therefore recommend you stop asking others to do this work for free and hire a consultant.

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#3

Re: Level Transmitter

07/04/2016 10:08 AM

The options may well be further reduced if the vapour above the liquid is flammable, which is something else the forum doesn't know.

It's never too late to consult a local specialist.

Make the calls.

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#4

Re: Level Transmitter

07/04/2016 10:29 AM

4-20mA probe, but preferable Radar, ultrasonic or laser for a positive level control. Which we use in a reactor column when we even have a stratification of different SG of product in it.

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#5

Re: Level Transmitter

07/04/2016 11:56 AM

Get a metal one of these.

It's called a dipstick.

It's solar powered, so it never needs batteries.

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#7
In reply to #5

Re: Level Transmitter

07/04/2016 3:44 PM

<...dipstick...> Touché.

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#6

Re: Level Transmitter

07/04/2016 2:33 PM

Hire her .... she stands a better chance of foretelling what's in your 6 meter tank and what level it's at

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#8

Re: Level Transmitter

07/05/2016 7:43 AM

I was able to set up a remote silo level measuring system using a Fluke laser measuring device and a USB connection from the following company...

http://www.porcupinelabs.com/lr4/

From the USB I connected to ethernet and can access the silo measurement from anywhere on our network. It's a great little system we put together for thousands less than any of the off the shelf suppliers.

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