VEGA VEGABAR 44 4 … 20 mA - Manual (Page 27)

VEGABAR 44 (4 … 20 mA) 27
Instrument modification
6.3 Exchange of the hygienic form
seal
On the VEGABAR 44 process pressure
transmitter with hygienic fitting LA or LB, the
ceramic measuring cell is sealed by a
gapless, radial form seal. This form seal
(material EPDM-FDA
1) approved) can be
exchanged by the user without readjustment
being necessary. The criteria and time peri-
ods for such an exchange are determined by
process conditions and hygienic require-
ments.
Important:
Only use the original VEGA replacement part,
article no. 2.17 775 as seal ring!
Note the following procedure when exchang-
ing the seal.
Removal procedure:
1 Pressure transmitter should be unpres-
surized (switch off process pressure or
empty vessel).
2 Loosen the hexagon head screw (46 mm
across flats) (1) by turning counter-
clockwise
Note!
The process connection (2) (i.e. sleeve nut)
must not be loosened!
3 Completely loosen compression screw
(hex head) and remove the pressure
transmitter from the process connection
Note:
Should the pressure transmitter turn when
loosening the compression screw (head
hex), it can be held by the adapter (3) with a
wrench (36 mm across flats).
4 Slightly lift the form seal (5) (with a knife
or similar utensil) and loosen it from the
ceramic measuring cell
5 If the form seal (5) does not completely
surround the measuring cell, it should be
carefully removed from the process
connection.
Installation procedure:
6 Pull a new form seal (5) over the measur-
ing cell (the conical side should point
towards the process connection!).
7 Insert the pressure transmitter carefully
into the process connection by turning
clockwise.
8 Tighten hexagon head screw (46 mm) (1)
to its fixed position (45 Nm).
9 Rotate the housing (4) of the pressure
transmitter to its original position
Exchange of the form seal is now finished.
Ensure proper disposal of the removed seal.
1) Food and Drugs Administration
1 Hexagon compression screw
2 Process connection
3 Adapter
4 Housing
5 Form seal