scope:

Guideline VDI 3839 Part 7 provides an overview of the specific vibration problems occurring with pumps with nominal output ratings over 1 kW which are used in installations and equipment. The main area of application of the pumps dealt with in the present guideline covers fluid kinetic machines and positivedisplacement pumps for moving liquids and suspensions in industrial applications, in the energy industry as well as in supply and disposal installations. This guideline also covers machines for gas production or vacuum generation which in general usage are also called pumps. Pumps in hydraulic power stations are dealt with in VDI 3839 Part 6. A large variety of pumps is used in engineering. They may vary a great deal in their design and power ratings. An overview may be found in VDMA 24261 although not all of the types it mentions can be covered here in any great detail.

General information about the measurement and analysis of machine vibrations and the vibration problems which can arise in all rotating machines is given in VDI 3839 Part 1 and Part 2. This general information will not be repeated here unless this is necessary in describing the special features of pumps. When pumps are powered by electrical machines, reference should also be made to VDI 3839 Part 5. Special information is provided in VDI 3839 Part 6 regarding pumps in hydraulic power stations.

This guideline is intended to provide the machine manufacturer, the plant engineer and the operator with information about identifying the causes of troublesome vibrations which may in the long term result in damage and also to recommend remedial measures. In many cases problematic vibrations do not occur until the machine is actually operating in its intended location and then need to be analyzed quickly in order to prevent operational disturbances. In most cases the problematic vibrations can be traced back to just a few characteristic causes. By far the commonest causes are

• imbalances

• misalignments and

• roller bearing damage.

Natural vibrations and fluidics-related excitations are also relatively frequent causes. On the other hand, a wide variety of other causes is found in the less common special cases. Both the characteristic and also the special vibration problems found in practice will be explained in Section 3 with the aid of examples, and their manifestations and causes systematically presented.