Solartron Mobrey 7828, Technical Manual

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Mechanical Installation 7828 Density Transmitter Technical Manual
2-12
78285000_AB
For hygienic applications , normal 2” hygienic tube is too thin for this application; (it can
vibrate in sympathy with the fork, causing measurement errors). Use 3” hygienic tube and
fittings instead, or fabricate hygienic fittings with the same wall thickness and internal
diameter as those shown in the diagram above.
2.3.5 T-PIECE WELDOLET INSTALLATION
This is the preferred option where temperature variations are a critical factor. The
reduced thermal mass of the weldolet's taper-lock fitting renders it more able to track
rapid changes in temperature.
Conditions:
Flow: 0.5 to 3.0m/s at the main pipe wall
Operation is possible with higher flow rates, if dimension X is
increased
( see diagram below ) .
Viscosity limit: Up to 100cP, or 250cP under some conditions (See section 2.2.2)
Temperature: -50
°
C to 200
°
C
The weldolet has a 1.5" taper lock fitting, and is supplied to be welded on 4", 6", 8" or 10"
pipelines. Use of the weldolet ensures that the tines of the 7828 are orientated correctly
and are fully inserted into the fluid stream. The length of the weldolet is determined by the
flow rate in the main pipeline (refer to the table in the diagram below), and is chosen to
ensure that the tines of the 7828 are sufficiently retracted from the main pipe wall.
Dimension X should be the smallest possible, consistent with the maximum expected flow
rate.
Before fitting the weldolet, the pipeline must be bored through at 52.5mm diameter to
accept the viscometer. The weldolet must be welded to the pipeline concentrically with the
pre-bored hole. The view shown below is schematic to show the relevant dimensions.
Flow velocity at the pipe wall and fluid viscosity must be within the limits shown to ensure
that the fluid within the pocket is constantly refreshed. This installation will not respond as
rapidly as the free-stream installation to step changes in viscosity.
D
X
264mm Y
O52.
5m
in
DimY = Dim X - DimD + 43
3 m/s
4 m/s
5 m/s
6 m/s
Max flowrate
25.4
35.4
45.4
55.4
Dim X mm
Carbon Steel
Stainless Steel
The installation must conform to Schedule 40 pressure ratings. Alternatively, schedule 80
tube may be used, but this will affect the calibration, and must be specified when ordered
the sensor.
The weldolet fabrication is rated to 100 Bar at ambient temperature.
Note: Correct installation and pressure testing of the fitting is the responsibility of
the user.
Max flowrate Dim X mm
3 m/s 25.4
4 m/s 35.4
5 m/s 45.4
6 m/s 55.4