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

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

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?

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.

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



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.

Carl Many Thanks for your Support.