DP level Transmitters with external dipahragm seals a normal standard irrespective of the process?? 1

[joji90]

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HI Everyone,

i need to measure the level in a vessel,open to atmosphere , i plan to do it with a DP transmitter connected on high side and low side vented to atm. My medium is liquid fuel gas from Gas turbine Generator. i understand that DP level Tx can be connected with and without external diaphragm seals but i find most of the time its with with exter
nal diaphragm seal. My medium is not corrosive nor high temp or plugging . is remote diaphragm seals normally used for better response time as we are dealing with very low pressures?? also emerson product line with 3051L always shows the connection with seals.

Thanks in advance,
joji
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[danw2]

Every liquid-filled, sealed system is as much a thermometer as it is a pressure transfer system.

Adding a remote seal when it is not needed is only asking for additional temperature error, not to mention the cost.

If the medium is not corrosive or too hot to closely mount the transmitter, there's no reason to encure the upfront cost and potential for temperature error of a remote seal.

If there's a flange at the bottom of the vessel, then a traditional flange mount DP transmitter is the ticket. We always use a sintered bronze exhaust filter in the low side port to prevent insects from making a home inside the transmitter.

No, remote seals do not offer faster response. Fact is, remote seals introduce a measuring 'lag' time and a damping effect on the transfer of the pressure.

Emerson is an industry leader in marketing and remote seals generally double the cost of a transmitter, which is why you see them promoting remote seals.