Drum level measurement with DP trx
Drum level measurement with DP trx
(OP)
On site we have differential pressure transmitters used to measure drum level, at pressures of 110 bar, 25 bar and 4 bar respectively. the sensing legs of the DP trx have demineralized water. In the winter, the trace heating is not enough so when there is no generation the water lines get frost and the signal has problems. If we put glycol in the sensing legs, then probably we will need to make again the zero of the trx? is there any problem since glycol is more heavy than water?





RE: Drum level measurement with DP trx
RE: Drum level measurement with DP trx
If your heart is set on wet legs (uggg) glycol gets pretty thick in the cold. you might need to go from a 60/40 glycol (assuming that is what you are using) to a 20/80 or a methanol gut mix.
open the pocket book and get capilaries...you wont regret it.
RE: Drum level measurement with DP trx
RE: Drum level measurement with DP trx
There also used to be a commercial barrier fluid for purchase for these type of applications too but, I can't remember the brand name.
I've never seen capillaries being heat traced. Your choice of capillary fill fuid would be chosen to suit your specific climatic conditions.
RE: Drum level measurement with DP trx
The sensing lines can be filled right at the transmitter, and can be isolated at the transmitter to periodically check operation and calibration whereas to check capillary transmitters you have to go to the process taps; on tanks these nozzles often are not readily accessible without scaffolding or other means.
On the other hand if the lines are not refilled regularly or if someone unwittingly opens the equalizing valve between high and low taps, the fill fluid level will not remain consistent and the transmitter's output will not be accurate.
Personally I am partial to "wet legs" over capillaries in all instances save those most prone to clogging such as very heavy oils, VTB, and catalyst slurries to name a few.
RE: Drum level measurement with DP trx