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Innovation & Technologie Angebot

3D printed instrumentation for steam turbine maintenance

Country of Origin: Italy
Reference Number: TOIT20190830001
Publication Date: 30 August 2019

Summary

An Italian company, working in the mechanical design and additive design, has developed and successfully applied a 3D printed instrument for maintenance checks of steam turbines, particularly in geothermal applications, providing advantages over conventional techniques.
Partners are searched for financial agreement.

Description

The present worldwide quest for renewable energy sources has focused a renewed interest in less exploited sectors, such as the geothermal one.

Italy has a long tradition in geothermal energy plants, but many other European countries are active in this area. In fact, the European region as a whole holds 36% of world's geothermal generated energy, that is 30 GW of power.

Geothermal plants have peculiarities that make their operation different from other more common systems.

In particular, geothermal steam from underground sources may contain residues of silica and corrosive substances that produce scaling and corrosion in pipes and particularly in the turbines used for electricity production.

For this reason, maintenance schedule is more tight than in other plants. Technical interventions are necessary to assess their reliability, evaluate erosion due to corrosion, provide replacement of faulty (deformed) blades on turbines, perform descaling, check the parts against the allowed dimensional tolerances to ensure a good efficiency.

The company, based in the Southern Italy, works in the sector of mechanical design, additive design and reverse engineering, realizing prototypes and components, up to the production of small series. Their established experience in 3D printing for industrial and technical applications allowed to develop the proposed new solution for dimensional checks on turbines. 3D printing with FDM (Fused Deposition Modelling) technology has been applied for the creation of the final tool.

The present offer deals with a 3D printed control instrument conceived for steam turbines, particularly the ones used in geothermal plants.

In more detail, the tool integrates a positioning template and three independent calibres used for dimensional control of the grooves, minimum distance between two neighbouring blades, and for shovel-blade positioning.

The tool, made up of thermoplastic polymer with low thermal contraction and good mechanical properties, works only mechanically, without any electronic device.

The control technique is based on two main steps:

1.	place the template on the back of a shovel, until it reaches the stop and make sure to attach the ridge to the lower strap 

2.	insert the callipers

3.	– In the case of a dimensional check: check if the groove size is within the expected tolerance range.

4.	- Instead in the case of a shovel-shovel positioning: position the calibres and insert the next shovel until it is brought into contact with the references of the calibres themselves

The SME is open for cooperation in the form of joint venture agreement and financial agreement.

They believe that other application fields, beyond that of power steam turbines already explored, can take advantage of a "new class" of measuring instruments that showed to be affordable and easily customisable.

Company is looking for a financial agreement in view of enforcing the technology already developed in new sectors, improving the software and exploring the possibility of directly producing spare parts in every industrial sector energy.

Advantages and Innovations

At the moment real advantages coming by the use of the tool can be seen in the operation of geothermal power plants: faster and more reliable maintenance controls, with reduced downtime.

The tool is simple to use and can be easily built and replicated with a professional 3D printer.

Furthermore, 3D printing allows a high degree of customization of the tool itself, so allowing to adapt it to different kind and sizes of turbines.

The customisation process requires a very limited extra effort. The usual dead time between design of a new customised version and its availability as a final product, is minimised thanks to the straightforward production process intrinsic to 3D printing.

The classical procedure for dimensional control consists in passing balls of a suitable diameter (equal to the theoretical height of the groove) through two consecutive blades. Some critical issues have been found, below are some of them:

- lack of repeatability of the control

- unpredictability of the trajectory of the spheres

- absence of a geometric reference with respect to the shaft axis

- time needed to make the balls (typical process: molding,  roughing, grinding, lapping)

- difficulty in controlling multiple shovel sections simultaneously

No attempts seems to have been made so far to find a new system that removes all the problems of the classical method.

The new instrumentation is a valid substitute for the traditional method essentially for the introduction and development of a positioning template. The reference fins of the template ensure that each calibre is always positioned with repeatability at the same diametral height of the blade section, making the process quick and repeatable.

The Italian company entered this new field merging mechanical design and additive manufacturing, allowing the production of callipers in a customised arrangement, with competitive costs and in a very short time.

Stage Of Development

Available for demonstration

Requested partner

Type and activity: enterprises, companies and investors working and interested in the all those realities and mechanical workshops that deal with maintenance or construction of turbines in general.



Role: the ideal partner should finance the project for further developments, in order

•	to buy a new 3D printer for polymers and / or metals;

•	to develop furthermore the software, especially for the realization of precision instruments, a certain attention is required for the compensation or resolution of all those problems related to the printing process. For example, the dimensional withdrawal of the material is one of the primary pitfalls that could compromise the functionality and accuracy of the instrument. For this reason it would be necessary to study and implement compensation laws that act directly on the CAD model in order to reduce the withdrawal phenomenon.

•	to produce directly spare parts in every industrial sector energy, in order to evaluate the access in new markets.