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Steam and Gas Turbine Sets
MEASUREMENT OF VIBRATIONS AND EVALATION OF THE TECHNICAL CONDITION OF STEAM AND GAS TURBINE SETS.
The measurement is limited to that of physical quantity sets which can be used to define and evaluate unambiguously the machine or device’s dynamic condition
Such measure is conducted in order to:
- Locate the sources of vibrations and determine their causes,
- Assess the vibration degree: current condition compared to the history of the machine,
- Collect data to make a complete analysis of the vibration state: current condition compared to the history of the machine,
- Interpret the vibration state observed: current condition compared to the history of the machine,
- Make a diagnosis regarding the technical state of the turbo set: current condition compared to the history of the machine,
- Make a forecast about the future technical state: current condition compared to the history of the machine,
- Prepare data concerning the time-span necessary for the repair and its scope.
Type and Scope of Measurement
We conduct measurements on turbine sets which are operating or disabled.
Measurement of an operating turbine set’s vibrations is conducted with:
- a monitoring unit mounted permanently: the so-called turbine set monitoring system,
- sensors of a stationary monitoring system mounted on the turbine set,
- a measuring system installed by us for a longer period of time,
- a measuring system installed by us for a period during which the measurement is carried out,
- a portable measuring apparatus.
In each of the above cases, if necessary, the measuring system can be supplemented with sensors essential for obtaining the best description of the turbine set’s technical condition.
The scope of measurement we conduct depends on requirements, objectives and a technical problems occurring while the turbine set is operating.
Depending on the scope of the measurement, we are able to indicate and inspect the following basic faults of the turbine set:
- Flaws of the rotating system’s balance,
- Flaws of alignment,
- Seizures in seals,
- Looseness in bearing supports,
- Misalignment of the rotor in the generator’s stator,
- Axial displacement of the rotor in relation to the generator’s stator,
- Thermal deformation of the turbine rotors,
- And many more.
Inspection of a disabled turbine set is geared towards:
- Defining, in the course of a repair of a given blade system, a safe degree of the dynamic free vibration frequencies’ offset from exciting forces that could cause dangerous resonant vibration,
- Defining the degree of an offset from resonance for blades and blade packs,
- Defining, in the course of a repair, a safe degree of an offset for blade discs’ dynamic free axial vibration frequencies from exciting forces that could cause dangerous and destructive resonant vibration,
- Defining the type of vibration and the value of dynamic frequencies,
- Making sure that blade disks are mounted correctly on the turbine’s shaft of the rotor,
- Defining the possibility of disc looseness according to the frequency of exciting forces occurring in the course of operation in order to eliminate an instability (self-excited vibration) of the rotor caused by dry friction,
- Analysing the possibilities of a potential standing wave as the most destructive form of disc vibration of the blade system.
We indicate loosenings or any possibility of looseness in the blade disk or clutch plate mounting on the shaft of the rotor. Measurement is carried out when the rotor is disabled, for example, during a repair of the unit. For this purpose, we use a method developed by the VIBROPOMIAR Company on the basis of modal analysis.
Measurement is geared to wards defining ranges of turbine sets’ actual critical velocities.
Moreover, we determine the frequencies of the free vibration of turbine sets’ elements. In this rolex replica watches way the elements inspected are secured against damage caused by resonant vibration. This enhances the safety of operation.
The VIBROPOMIAR Company also maintains a measuring team which responds to emergencies. It conducts limited measurement consisting of the evaluation of the rotating system’s vibration condition. This measurement serves the purpose of assessing fitness of a rotating system for further operation, making it possible to evaluate its technical condition .
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