Monitored Machine

The monitored machine is a secondary LDPE Hyper Compressor (high pressure compressor) in Ethylene service of LDPE production line.

What happened? Sequence of events

  • On March 29, the PROGNOST System tripped the Hyper compressor in consequence of high plunger vibration on cylinder 2A
  • Vertical position lead LDPE unit for total shut down
  • The Maintenance group of the customer, started the root cause analysis with assistance of the PROGNOST Systems Customer Support team, they analyzed the data and finally recommended to open the cylinder for inspection
Pk to Pk
Trend over 60 minutes of plunger position Peak-to-Peak values


As a result of the cylinder opening the following findings where detected.

  • In the plunger path way they found Chips of packing ring material.
  • The packing has made a heavy marking on the plunger at the main contact area
  • The packing cup was found to be damaged
Damaged packing
Damaged packing of the Hyper compressor
piston rod
Hyper compressor plunger with markings due to the metal chips from packing

The PROGNOST System tripped the hyper compressor at the right time, therefore costly consequences and secondary failures where avoided.