Endress+Hauser Micropilot FMR51 - Installation in Stilling Well; Recommendations for the Stilling Well

Installation Micropilot FMR51, FMR52 FOUNDATION Fieldbus
30 Endress+Hauser
6.5 Installation in stilling well
1
90°
A0016841
 8 Installation in stilling well
1 Marking for antenna alignment
• For horn antenna: Align the marking towards the slots of the stilling well.
• Measurements can be performed through an open full bore ball valve without any
problems.
• After mounting, the housing can be turned 350° in order to facilitate access to the
display and the terminal compartment →  34.
6.5.1 Recommendations for the stilling well
• Metal (no enamel coating; plastic on request).
• Constant diameter.
• Diameter of stilling well not larger than antenna diameter.
• Diameter difference between horn antenna and inner diameter of the stilling well as
small as possible.
• Weld seam as smooth as possible and on the same axis as the slots.
• Slots offset 180° (not 90°).
• Slot width or diameter of holes max. 1/10 of pipe diameter, de-burred. Length and
number do not have any influence on the measurement.
• Select horn antenna as big as possible. For intermedaite sizes (e.g. 180 mm (7 in)) select
next larger antenna and adapt it mechanically (for horn antennas)
• At any transition (i.e. when using a ball valve or mending pipe segments), no gap may be
left exceeding 1 mm (0.04 in).
• The stilling well must be smooth on the inside (average roughness R
z
≤
6.3 μm (248 μin)). Use extruded or parallel welded metal pipe. An extension of the pipe
is possible with welded flanges or pipe sleeves. Flange and pipe have to be properly
aligned at the inside.
• Do not weld through the pipe wall. The inside of the stilling well must remain smooth. In
case of unintentional welding through the pipe, the weld seam and any unevenness on
the inside need to be carefully removed and smoothened. Otherwise, strong interference
echoes will be generated and material build-up will be promoted.
• In the case of smaller nominal widths flanges must be welded to the pipe such that they
allow for a correct orientation (marker aligned toward slots).