PROGNOST®-SILver Safety Protection

The SIL-compliant PROGNOST®-SILver "Safety Protection" is based on parameters of crosshead vibration, dynamic cylinder pressure and piston rod/plunger positions and offers a diagnostic technology that is especially designed for reciprocating compressors.

The vibration behaviour of all critical motion work component connections between drive shaft and pistons need to be continuously monitored. Vibration data is recorded at a high resolution sample rate of 25 kHz: The vibration signals for each revolution are divided into 36 x 10° crank angle segments and are analyzed continuously. The sampling speed together with fast analysis techniques allows the identification and confirmation of a safety risk within a fraction a second and - at the customer’s option - an immediate machine shut down.

Recommended signal analyses for different machines

Signal Piston Compressor Plunger Compresssor Piston Pump
Vibration
Crosshead
(Acceleration)		 RMS
36 Segments		 RMS
36 Segments		 RMS
36 Segments
Housing
(Velocity)		 RMS
1 Revolution		 RMS
1 Revolution		 RMS
1 Revolution
Bearing
(Acceleration)		 RMS
36 Segments		 RMS
36 Segments		 RMS
36 Segments
Position (Proximity)
Piston rod position Peak-to-Peak
8 Segments		 - -
Plunger position - Peak-to-Peak
1 Revolution		 -
Shaft vibration Peak-to-Peak
1 Revolution		 Peak-to-Peak
1 Revolution		 -
Axial thrust Average Average -
Dynamic pressures
Indicated pressure Peak-to-Peak
1 Revolution		 - -
Suction & discharge pressures Peak-to-Peak
1 Revolution		 - Peak-to-Peak
1 Revolution
Temperatures
Bearing Average Average Average

Plausibility check and decision making

In addition to vibration data, piston/plunger position and a cylinder indicated pressure can be utilized. An e.g. rapid variation in piston or plunger position might be caused by fоreign particles inside the cylinder or loose components, and indicated pressure differences over one revolution could indicate an overloaded piston rod.

Your advantages

  • Fast, crank angle related vibration analysis
  • Permanent comparison of the vibration signal with the safety limits in 36 segments
  • Monitoring of indicated pressure and piston rod/plunger position
  • Individually adjustable safety limits
  • Option: Automatic machine shut down if safety limits are exceeded
  • Event controlled time signal storage in a ring buffer for subsequent analysis

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