Mounting Cageless Sensors - Fisher 2502 Series Level-Trol Instruction Manual

AH9150–A
A2613–2/IL
Figure 4. Cage Head Mounting Positions
If the controller is not mounted on the
sensor, refer to the Installing Controller
on Sensor section. That section also
provides instructions for adding a heat
insulator to a unit. If a temperature-com-
pensating displacer or piezometer ring
is used, refer to the special installation
procedures in this section before pro-
ceeding.
Cage connections will normally be either 1-1/2 or
2-inch (38.1 to 50.8 mm) screwed or flanged. Figure 5
shows the combinations. It is recommended that a
drain be installed between the cage and shutoff or
hand valve whenever the bottom cage line has a liq-
uid-trapping low point.
Mount the cage by running equalizing lines between
the cage connections and the vessel (figure 6). On
liquid or interface level applications, position the sen-
sor so that the line marked FLOAT CENTER on the
cage is located as close as possible to the center of
the liquid level or interface level range being mea-
sured.
Note
A1271–2/IL
Figure 5. Cage Connection Styles
For liquid or interface level applications, it is advanta-
geous to install a gauge glass either on the vessel, or
on the sensor cage (if the cage is tapped for a gauge).
With flanged connections, use standard gaskets or
other flat-sheet gaskets compatible with the process
liquid. Spiral wound gaskets without compression-con-
trolling centering rings cannot be used for flanged con-
nections.
Mounting Cageless Sensor
CAUTION
If a stillwell is used, it must be installed
plumb so that the displacer does not
touch the wall of the stillwell. Should
the displacer touch the wall while the
unit is in service, the unit will transmit
an erroneous output signal.
Since the displacer hangs inside the vessel, it is advis-
able to provide a stillwell around the displacer when
the liquid is in a state of continuous agitation and ex-
cessive turbulence can be expected.
2502 Series
5