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Vertical tube-housing pumps are used in many applications, an important one of which is the power generation industry for cooling water circulation. One of the main monitoring requirements in machines of this type is for the shaft guide bearings.
This requirement arises from the inherently large amplitudes of vibration that can be produced as a result of severe turbulences, rotor unbalance and resonance that can drastically shorten the life of the guide bearings in these machines.
There are basically two different shaft guide bearing designs. The variants are a rubber bearing and a ceramic bearing (Residur® or ceramic fibre).
A new diagnostic monitoring system has been conceived that provides reliable, and in almost real-time, wear evaluation of the underwater shaft guide bearings. The solution focuses on the use of the appropriate sensor type and adaptation, sensor mounting and setup as well as data acquisition hardware and software for the application.
The sensor selection and mounting allows a "picture" to be formed of the real behaviour of the shaft within the bearing, complete with amplitude of vibration and relative position of the shaft centre.
A correlation between vibration, bearing clearances, power and current, and flow-vane position can provide sufficient information to assess the total machine condition. |
