Blanking disc
A blank is used for the temporary separation of a pipeline . For this purpose, the blanking plate is installed in a specially prepared flange connection .
With blanking disks, a section of a pipeline or a container can be separated (isolated) from the rest of a chemical plant or pipeline network. Such a separation is necessary for maintenance work (especially when containers are entered by personnel) and for a pressure test .
Designs
Designs without open disc are referred to as dummy wafer referred to as open slices open disc , with a bore such smaller nominal diameter than the throttle disc .
Spectacle blinds (to DIN EN ISO 10628: 2000 Umsteckscheiben ) combine reactive and open disks by two circular plates each welded are:
- the closure part as a flat plate with the hole pattern of the prepared flange connection ( blind disk ),
- the operating part with the same hole pattern and a hole with the same nominal width as the connected pipeline ( open disc ).
Adapter disks therefore only have to be converted for normal operation of the pipeline; The correct installation can be recognized immediately by the part protruding from the flange connection. Because of this shape, the lens is also called a spectacle lens .
Application example
In the second photo on the right you can see a yellow container through which natural gas flows during operation. Before the lid can be opened, the following steps must first be carried out:
- Close both slides (with the black handwheels above the stage)
- Release the gas and thus lower the high pressure in the container to ambient pressure. A few smaller fittings and pressure gauges are available for this.
- Loosen the screws on the flanges on which the blanking washers are located.
- Turn the blanking disks so that the side (shown in the photo) is without a hole in the line and the side with a hole protrudes.
- Retighten the screws on the flanges with the blanking washers.
literature
- Günter Wossog (Ed.): Handbook of pipeline construction. 3rd edition, Vulkan Verlag, Essen 2008, ISBN 978-3-8027-2745-0 .
- Johann Mutschmann, Fritz Stimmelmayr: Pocket book of water supply. 13th edition, Friedrich Vieweg & Sohn Verlagsgesellschaft, Wiesbaden 2002, ISBN 978-3-663-12398-9 .
Web links
- Blank (accessed February 25, 2016)
- Specialist standard pipelines and blanking plates (accessed on February 25, 2016)