This is an external extension of the vessel, to which multiple instruments can be connected.
Bridle in Level Measurement
A standpipe or Bridle should follow the pressure vessel code. Usually no instrument is installed inside the standpipe itself.
Isolation valves may be used between vessel and standpipe.
Each instrument connected should have its own isolation valves, vents and drain to facilitate maintenance. The distance between the standpipe and the vessel nozzle should not exceed 1 – 1.5 m.
Long connections could potentially cause temperature gradients, formation of hydrate and reduction in level coupling between the standpipe and the vessel