Instruction manual

Mounting
16 Installation and Operations Manual
4.4 Installation Instructions
4.4.1 Mounting kit
The following tools are required for mounting:
• The tool for flange mounting
• 4 mm (0.1") Allen wrench for turning the housing
4.4.2 Installation in tank (free space)
Standard installation
• Observe installation instructions, (see page 13).
• After mounting, the housing can be turned 350° in
order to simplify access to the display and the terminal
compartment.
Figure 4-6: Optimum Mounting Position
• Planar axis vertical to flange.
• Measurements can be performed through an open ball
valve without any problems.
Recommendations for the Stilling Well
• Metal (no enamel coating, plastic on request).
• Constant diameter.
• When using a 7532 RTG, an increase of the pipe diameter from DN150 to DN200 / DN200
to DN250 / DN250 to DN300 is acceptable. A larger step-width for the increase of the pipe
diameter (e.g. DN150 to DN300) is possible if the upper part of the pipe has a suitable
length. The length of the stilling well enlargement must be kept. In this case, the upper end
of the pipe must have a minimum length of 0.5 m (20") before the diameter increases (refer
to table, see page 18). If the length is less than “L”, please contact Varec in order to
determine a suitable antenna adapter (separable antenna horn). Ideally, a sample hatch is
used.
• Any rectangular increase of the pipe diameter has to be avoided.
• Weld seam as smooth as possible and on the same axis as the slots.
• For best radar propagation behavior holes it is recommended to have holes instead of slots.
• If slots can not be avoided, they should be as thin and short as possible.
• The diameter of the holes (deburred) can be up to 1/7 of the pipe diameter but should not
exceed 30 mm.
• Length and number of the holes do not affect the measurement.
• Maximum gap allowed between the antenna/horn and the inside of the stilling well is
5 mm (3/16”).
• At any transition (e.g. when using a ball valve or mending pipe segments), no gap may be
created exceeding 1 mm.
• The stilling well must be smooth on the inside (average roughness Rz  6.3 μm). Use
extruded or parallel welded stainless steel 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 smoothed. Otherwise, strong interference echoes
will be generated and material build-up will be promoted.
90°