I've read on many places that use of radar level gauges on LPG bullets and tanks are not good as they can be easily confused with the presence of fumes and can give mal results so i want to know what should be our first choice to measure level on such places keeping in mind that we only have process connections only at the top of the storage tanks.

 

Fumes from oil process, in some applications, will affect that instrument. I am not aware of LPG doing the same.

If you have concerns - try the less complicated and rugged http://www.almegcontrols.com/4-20_continuous.htm

Regards,
Bob Hogg

 

The problem with radar gauges and LPG is that the dielectric constant of LPG is very low (less than 2) compared with water (dielectric constant 80). The strength of the reflected wave is nowhere near as high as it is on water-based liquids.

Bruce

 

Hi,

Radar is measuring the distance between the gauge and the liquid by measuring the time it takes for a radar impulse to travel. The time is influenced by the medium it travels through, so it is different at different vapor compositions. Radar gauges can compensate this, but changes in pressure, temperature always influence this.

An alternative is a servo gauge for high accuracy measurement, which can measure the level of the liquefied gas. For lower accuracy in bullet tanks a guided radar can be a good alternative.

See http://www.endress.com for all of the above products.

Regards,
Toni Kaesbeck