The installation situation does not always permit the use of standard penstocks. If the channel or sewer to be shut off has a very great depth or the installation of a single-plate gate penstock is not possible because the building ceilings are too low, double-plate gate penstocks are used. The two gate plates can be moved independently of each other and seal against each other. They thus achieve a reliable and very high sealing performance in both pressure directions. Double-plate gates are always designed individually, according to the requirements of the application.