Measuring vibrations on a regular basis is a good indicator of a deteriorating condition of a machine. However, it is not a 100% guarantee against sudden failure. The reason for this could be rapid damage taking place imbetween two measuring periods. Also defects resulting from improper machine operation and machine overload cannot be predicted.
Vibration measuring offers the best means for early detection of roller bearing damages. But there is a problem that failure-relevant vibrations can be overlapped by natural machine noise.
The difficulty in analysing the vibration intensity of screw compressors and positive displacement blowers is to exclude the interfering pressure pulsation vibrations. This is obtained by configuring the evaluation parameter correctly.
VDI 3836 provides guidelines about measuring and evaluating vibrations of two-shaft positive displacement machines (screw compressors and Roots blowers) if measurements are carried out at the non-rotating and/or the rotating parts of such machines whilst in operation.

Evaluation of the machine condition by means of vibration measurements / machine diagnosis

Measurement and evaluation of vibration levels in screw compressors and positive displacement blowers according to VDI 3836 (DIN ISO 10816 – 1 / 3)

• Taking measuring data and evaluation
• Discussion of results and optimisation proposal with quotation
• Identification of the critical machines
• Development of the database
• Collection of data
• Inspection of data for irregularities
• Diagnosis of any machine faults

Vibration measurement

The vibration measurements are carried out with vibration measuring device, type B1910
analyser (Messrs. CSI) or with the analyser, type 6230 (inc.sensor
A0720GP – serial no. P30649).
This device fulfils the following standards:

• EN 50081-2: 1994
• EN 50082-2: 1995
• EN 61010-1: 1993

The measurements are recorded as narrow band analysis.