TL;DR

Vibration in a plate heat exchanger usually comes from flow velocity exceeding design limits or from loose pipework supports transmitting external vibration into the frame.

What you might see

audible humming or rattling from the frame
vibration measurable on the connecting pipework
fastener loosening found during inspections
vibration worsens at higher flow rates

Likely causes

Tap to mark as ruled out

Flow velocity above the design range causing vortex-induced resonance in the plate pack
External pipework vibration transmitted into the PHE frame through rigid connections
Loose frame bolts allowing the plate pack to shift under pulsating flow
Pump pulsation from a reciprocating pump upstream

Required tools

Handheld vibration meter
Torque wrench
Flow meter or plant flow historian access
LOTO kit

Safety first

Verify zero pressure on both sides before tightening frame bolts.
Do not over-tighten frame bolts in an attempt to stop vibration. Over-tightening can damage gaskets.

Procedure

6 steps · ~45 min

1
Measure flow rates on both sides and compare to the design duty sheet for this unit. Elevated flow above the design maximum is the most common cause.[1]
2
If flow is within design range, inspect the pipe support brackets within 2 meters of the PHE connections. Tighten or add pipe clamps as needed.
3
Shut down and lock out. Check frame bolt torque per the Alfa Laval specification. Re-torque any bolts that have backed off.
Warning: Verify zero pressure on both sides before touching the frame bolts.
4
If a reciprocating pump is upstream, install a pulsation dampener between the pump and the PHE.
5
Consider installing flexible hose connections at the PHE nozzles to decouple pipework vibration from the frame.[1]
6
After corrective action, run the unit at operating flow and re-measure vibration on the frame with a handheld vibration meter. Target less than 2.5 mm/s velocity RMS.

Sources

Alfa Laval M-Series Plate Heat Exchanger Instruction Manual, Alfa Laval
Alfa Laval M-Series PHE Instruction Manual, flow velocity limits and installation requirements (general)
View source

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