Services
Blading
Replacing and repairing steam turbine blades is not only a highly specialized service and craft, but it also usually comprises the critical path of the maintenance plan.
Steam turbine blades are to be installed following strict procedures that in many cases include group packing and prestressing, among other mainly manual techniques. During our work, we have discovered these procedures are not always followed and sometimes not even known by a lot of bladers in the market.
Our team of bladers combines the expertise of the veteran with the energy of the young to do the job right and on time. We also own the right tools to perform precision drilling and reaming and the machining of the shrouds. Finally, the rotor is balanced in our transportable balancing machine.
Upon your request, we will gladly share information on documented cases. Please contact us if wish to know more.
Blade Tuning:
In steam turbines, some factors such as undesirable operating conditions, poor steam quality, loss of condenser vacuum, and increased humidity in the last stages, can cause and accelerate wear on the blades, leading to catastrophic failures. The detached parts are expelled at high speed, in some cases perforating the containment casing and thus compromising the safety of the area around the turbine. Damage to the rotor, diaphragms, and stationary parts can be expected, and major efforts are required to rehabilitate the unit. This type of failure is difficult to detect with the unit in operation. For this reason, it is essential to record the condition of the blades and other rotating parts, as well as to monitor the progress of erosion, whenever possible. When these mechanical failures develop in the last stages of the blades and no spare are available, the blades are usually completely removed or cut without performing an analysis of the impact on the mechanical and dynamic behavior of the unit. This practice can work, but results in loss of efficiency of the blade row and causes instability in the steam flow to subsequent stages. In addition, without adequate study to anticipate them, similar failures can be caused by mechanical fatigue in the short term.
Trimming blades or “Blade Tuning” is a proven technical solution in the industry. Although the power output of the unit is diminished, the loss is usually relatively small and tolerable, and the technical risk is low. The advantage of this repair is the considerable improvement in reducing the machine downtime and the repair cost.
We have developed a procedure for optimizing blade trimming, which allows us to efficiently preserve the biggest portion of the blade to achieve the highest power output by the repaired blade row in a safe and reliable operation. Our solution is turnkey, including field measurements of the natural frequencies of the blades (Bump Test), engineering analysis through finite element simulation (FEA), and finally machining, final polishing, and balancing according to ISO standards, in our transportable balancing machine and lathe.
Upon your request, we will gladly share information on documented cases. Please contact us if wish to know more.
