Venetian blinds
External venetian blinds (single number: external venetian blinds, the) belong to the external sun protection products and are closely related to the venetian blind . The terms blind and external venetian blind are often used synonymously. But the correct term for the blind, which can also be rigid, is the collapsible external venetian blind.
Similar to the venetian blind, external venetian blinds consist of the following components:
- Slats (usually made of roll-formed aluminum, anodized or powder-coated). Flanged lamellas and special shapes (e.g. Z-shape) are often used.
- Ribbons, also called cords or cords . Here it is important to distinguish between the ladder tapes (which are used for carrying, keeping the distance and turning the slats) and the elevator tape (for lowering or pulling up the slats);
- Upper rail (mostly as a U-profile), for fastening by means of retaining brackets, as well as for receiving the drive elements and power transmission components;
- Lower rail, also made of extruded aluminum, anodized or powder-coated;
- Crank and motor drives are common for the venetian blind.
Since external venetian blinds are exposed to higher loads from wind and weather, they are usually rail or rope guided. External venetian blinds can normally be extended up to a maximum wind speed of 17.4 m / s (corresponds to wind force 7 on the Beaufort scale). New developments can sometimes withstand gusts of wind of up to 25 m / s (wind force 10 on the Beaufort scale). For protection, they are automatically retracted in the event of strong wind loads ( wind monitor ).
Often several hangings are coupled via one shaft. In this way, on the one hand, smooth opening and closing can be guaranteed and, on the other hand, drives are saved.
Since external venetian blinds are attached to the outside of the facade, they are either installed in a niche or, with panels above the top rail, mounted in a curtain so that the top rail and the retracted lamella package are no longer visible. The advantage of external sun protection products such as external venetian blinds, awnings or the like is that a very high level of summer heat protection can be achieved, as the absorption heat resulting from solar radiation can already be dissipated outside in front of the window component to be shaded, and thus unwanted solar heat input into the interior of the building can be minimized. On the other hand, internal sun protection, for example in the form of a curtain or roller blind , is far less effective. Here, the heat generated by the sun protection remains in the room because the window component has already been passed.
One trend in further development is the use of sunlight in order to consume less electricity. There are now solar-powered versions as well as versions that save artificial light. In these so-called light control or daylight utilization versions, the slats attached in the upper area are responsible for allowing light to penetrate into the room without reducing the glare protection. This can be achieved once through perforated slats (daylight use). On the other hand, it is possible to divide the venetian blind curtain so that the upper curtain area can be controlled separately. This makes it possible to cast the incident daylight onto the ceiling and thus achieve indirect lighting with natural light.