Level Measurement - How to fill a remote seal (Capillary )


#1

DP remote seal Level Transmitter Capillary was broken. After installing new Seal with Capillary Transmitter did not give accurate measurement. can any body help me


#2

The installation or re-installation of a capillary and seal requires vacuum evacuation of the seal, capillary and pressure port to a hard vacuum level and then back-fill of the sensing elements with fill fluid. Any air left in the system will cause pressure measurement error.

That means that a replacement seal and capillary can not be mechanically replaced without vacuum evacuation and fill fluid back fill. Was that done without introducing air into the sensing system?


#3

Thanks for your Support. This was mechanically replaced without vaccum evacuation and reinstall new fill fluid capillary and seal. can u please tell me how to evacuate vacuum from pressure port. or any other suggestion to remove measurement error.


#4

There are two resources for techniques for evacuating and filling a remote seal.

http://www.enfm.net/catalog/filling/fillingprocedure.htm

http://www.fluidcontrolsinstitute.org/pdf/resource/gauge/TSI310DiaphragmSealFillingGuide.pdf

My opinion is that you are far better off finding a local service that has the equipment and experience to perform the task. If you use remote seals you probably work in a process plant so you probably have access to local instrumentation services. Providing remote seal services is at a local level is quite common. One finds out quite quickly whether the service knows what it’s doing by the performance of the transmitter. A poor job means either no pressure reading or time lagged pressure readings that are ‘squishy’ and not responsive to an step input change (applying a step in pressure to the seal diaphragm).

I know that the two technicians in my company’s service department that do that each went through a learning curve to learn how to do it correctly.

The equipment is not very specialized (vacuum pump, vacuum gauge, hoses, valves, fill fluid), but the vacuum gauge alone is a $1,000 vacuum gauge. The fill fluids are commercially available but at what volume and price? If you have buy 10L of fill fluid to fill a capillary and seal that takes 8ml is that a reasonable investment?

Seriously consider paying a service to fix it for you.


#5

Carl Many Thanks for your Support.