SUBJECT : Centrifugal pump vibration readings 2-9

It 's necessary to be concerned about vibration because it has a major affect on the performance of your pump. At least six components are seriously affected by vibration :

The vibration comes from a number of sources that include :

Mechanical causes of vibration

Hydraulic causes of vibration

Other causes of vibration.

You can read the vibration a variety of ways:

Many systems read vibration by recording acceleration. The problem with this method is that if you do not know the frequency the readings are not very meaningful. Because of this most systems read an average of all of the frequencies involved and recommend taking action when this average reading doubles in a particular location. If bearings are your primary concern high and low electronic filters can be used in some equipment to filter out frequencies below 55 Hz. and above 2500 Hz. These filters will help the operator zero in on those frequencies normally associated with bearing problems.

Unfortunately, most vibration data references bearing operation. There is little to no information available about mechanical seal vibration modes. The problem is further compounded by:

The vibration readings almost always means that the equipment has started to destroy its self. Most companies are trying to collect enough data to predict the remaining life before total destruction takes place.

The obvious solution to all of this is to adopt good maintenance practices that 'll eliminate most of the vibration and then try to install hardware that can live with the vibration you have left. Recording vibration makes sense only after good maintenance practices are in force.

Mechanical Problem Solutions

Hydraulic Problem Solutions

Solutions to other types of vibration

Most of us can not stop all of the vibration that is causing our seal, packing, bearing, and critical clearance problems, so our only solution is to live with it. Unfortunately the standard pump and original equipment seal is not prepared to handle vibration without major modification.

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