I want to measure level of hotwell tank/condensate tank in power plant. i have used siemens make dp transmitter but there to much haunting in level because it's closed tank under vacuum. so, suggest any solution so that i can reduce haunting in level measurement

 

"Hunting" is generally associated with closed loop control. If it is "cycling" then controller settings need to be adjusted. if truly "hunting" then you typically have a valve maintenance problem do to a sticking valve of malfunctioning actuator.

 

Speaking from purely a level measurement standpoint, you might consider using a Guided Wave Radar level transmitter for this application. Given that you have fairly warm water under vacuum conditions you are probably operating at or near the vapor pressure of the condensate which makes it very difficult to keep the low pressure leg of the DP transmitter line full of liquid. At these conditions, the water will vaporize leaving a partially full sensing line which is likely causing your measurement error. I have seen the Guided Wave Radar technology used very successfully in these exact applications. GWR probes are also offered with 'hermetically sealed' probe designs which is recommended for high vacuum services to prevent any additional air leakage into your condenser. I suggest contacting your local Magnetrol International representative if you need assistance selecting a transmitter and probe combination.

 

Yogesh,

The hunting could be due to air ingress into the impulse lines..This we have faced in the glass tube level gauges...

Also it may be checked that if there is any steam flow directed on the side where the impulse lines are located... This can also cause hunting..

We are having displacer type magnetrol level transmitters.. never had this problem...

 

As mentioned by one friend. You may go for radar type or displacer type of level transmitter. Here the<b> make of DP transmitter is not the matter of concern.</b>

By the way,if in your plant there are 03 transmitter for level measurement of hotwell, what are the type of other 02 nos of LT.If you are not going to use the same type for the third one,their may be chance of difference in speed of response, accuracy, accuracy in different seasons(!!!!!!!) etc..

if any query, pls ask