INSTALLATION, OPERATION and MAINTENANCE MANUAL | 45
Check that the tie bar threads are free from damage. Clean the tie bar threads and
liberally apply the applicable anti-seize compound along the area where the nuts will
travel during tightening. Also apply the compound to both sides of the plain washer
under the tie bar nut. APV recommends Never-Seez Regular Grade Lubricant for
carbon steel tie bars and Never Seez Black Moly Lubricant for stainless steel tie
bars. White or clear, food grade grease is recommended for plate heat exchangers that
will be used in food processing plants. Do not use standard grease as it may result in
galling. Figure 40 shows an assembled frame with tie bars installed.
Never-Seez Regular Grade is not suitable for stainless steel tie bars.
9.6. Closing Tie Bar Frames
These instructions provide a method to safely tighten an APV Plate Heat Exchanger
with tie bars. Correct tightening is essential for satisfactory operation and maximum
gasket life. These instructions should be followed closely for both initial assembly and
whenever the exchanger is closed after maintenance.
1) Confirm the plate installation (section 9.4) and tie bar installation (section 9.5)
steps have been completed. Install tie bars 1 through 4 when the distance
between tie bars 1 and 3 is less than 1200mm (4 ft.) or install tie bars 1 through
6 when the distance between tie bars 1 and 3 exceeds 1200mm (4 ft.) (Figure
41).
2) The sequence for tie bar tightening starts with the upper tie bar pair (1 and 4),
then move to the lower tie bar pair (2 and 3), and if necessary, move to the
center tie bar pair (5 and 6). Repeat this sequence as many times as necessary
to complete step 2. Tighten the tie bars evenly in 12.5mm to 25mm (1/2 in. to 1
in.) increments until the platage dimension (thickness of the plate pack)
measured at the installed tie bars is equal (+/- 3mm or 1/8 in.) and the follower
is parallel to the head. The final measurement in step 2 should be
approximately 10% greater than the final plate dimension specified on the plate
arrangement diagram. Throughout this step, ensure the dimensions at each
adjacent tie bar remain within 6mm (1/4 in.) of each other. Also, always tighten
the top pair of tie bars first to keep the plates from riding up.
Note: It is important that head and follower are kept parallel during the
compression work. In this regard, compression must be measured at the top,
middle, and bottom sides. Measurements are to be taken close to the tie bars.
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