Usage conditions, creepage, and voltage class are just a few examples of the parameters that come into play when the right shielding for hollow insulators is being designed. Various shielding options are available to suit whichever group of parameters is present in an application. Previously, Reinhausen Power Composites used liquid silicone rubber (LSR) shielding technology at the Regensburg site.
In mid-2017, however, an acquisition in France introduced a new method: the high-temperature vulcanizing (HTV) extrusion process. As a result, Reinhausen Power Composites, as a full-range supplier and reliable partner, offers its customers solutions for any requirement, with each made to satisfy the very highest standards of quality and safety. Here, we showcase both technologies and highlight the applications for which they are particularly suitable.
INJECTION MOLDING FOR LARGE-SERIES PRODUCTION
LSR injection technology is an injection molding technology. It involves first clamping the precursor product, made from glass reinforced plastic (GRP) piping and an aluminum fitting, in a device. Following this, two mold halves encase the assembly and the machine then presses liquid silicone into the mold under high levels of temperature and pressure. Once the silicone shielding has been cross-linked, the mold is opened and the insulator can be removed. After that, the next shielding can be molded.
The mold halves consist of a large number of mold plates. The length of the shielding can be adjusted by changing the numbers that are used. The LSR injection method is ideal for highly standardized insul ators that are produced at high volumes. This means that, in larger-series production in particular, there are cost advantages to be gained from it. Because it is relatively expensive to purchase an individual mold, the method is less suitable for smaller batch sizes.
EXTRUSION FOR CUSTOM REQUIREMENTS
In the HTV extrusion process, an extruder applies silicone, which has the consistency of plasticine, to the precursor product. The precursor product then moves about its own axis as well as in the direction of the longitudinal axis, creating spiral-shaped shielding on the GRP pipe. A mold plate on the extruder determines the geometry that the shielding will have. This allows even the most complicated shielding profiles to be created.
A key characteristic of HTV extrusion technology is its high flexibility, which makes it ideal for creating custom shielding profiles. Because the mold plates are relatively inexpensive to manufacture, customers can choose a shielding profile that meets their exact needs. Special shielding profiles, such as those with drip edges for ultra-high-voltage DC applications, can only be manufactured using this method.
Since mid-2017, Reinhausen Power Composites has been manufacturing shieldings using HTV extrusion technology at its facility in Cusset, France. You can find out more about this new facility in the exclusive online interview with the site’s director, Marcus Hartmann.
Do you have any questions about the shielding process?
Georg Schütz is here to help: firstname.lastname@example.org
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