46
47
Use the guide bars to ensure that the plate pack is repositioned successfully and safe-
ly. Check the position of the plate pack relative to the shell.
Lubricate the flow director rubbers, with vegetable oil, for example, to facilitate reposi-
tioning.
When the plate pack is being mounted in the shell, the position of the flow directors
must be checked continuously.
5.3.4 Bolt/nut tightening pattern
When tightening bolts,
never use an impact tool. It is important to tighten the bolts to
the same torque value. Always use a torque wrench or other calibrated tightening tool.
The sequence in which the bolts are tightened has a substantial bearing upon the
distribution of the pressure on the gasket. Improper bolting may move the flange out
of alignment. A gasket will usually allow for a small amount of distortion of this kind.
Always tighten the bolts in a cross bolt tightening pattern. See the drawing, where the
sequence is numbered.
Always screw in the nut or bolt by hand. This ensures that the thread remains in satis-
factory condition (if the nut will not screw in by hand, check the thread, replace dam-
aged parts and start again).
Tighten the connections using a minimum of 5 revolutions, following the sequence. The
following procedure is recommended:
Revolution 1 – Start the bolt tightening by hand following the sequence, after which all
of them should be evenly tightened by hand.
Revolution 2 – Using a torque wrench, tighten the bolts, following the sequence. Use a
maximum of 30% of the eventual tightening torque. Check the position of the gasket
between the cover plate and flange.
Revolution 3 – Tighten using 60% of the eventual torque, following the sequence.
Revolution 4 – Tighten to full torque in a clockwise direction.
The tightening toque on lubricated bolts is stated in the GA drawing supplied with the
exchanger.
6 Expandable Plate Pack
An openable pack model may be expandable to facilitate the cleaning of the pack, for
which separate instructions are available. Contact Vahterus for further information.
1
12
20
8
16
4
10
18
6 14 2 11
19
7
15
3
9
17
5
13
