摘要 |
The invention relates to a shut-off device (4a, b, c) for a flow channel. The shut-off device has two devices (5, 6a, b, c), especially flaps, for opening and closing the flow channel, a chamber (7a, b, c) located between both devices, a line (9a, b, c) leading to said chamber, a device (10a, b, c) for filling or emptying the chamber, for instance a pressure apparatus or a vacuum apparatus, and a device (8a, b, c) for measuring the pressure in the chamber. The shut-off device makes it possible to interrupt the gas flow in the flow channel, whereby penetration of said gas flow into adjacent parts of the facility can be temporarily prevented. It is possible to perform leak tests of the shut-off device by generating a negative pressure or an overpressure in the chamber between both flaps. If changes in pressure are observed, which can vary depending on the method, the existence of a leak can be inferred. In order to prevent resulting ignitions or explosions, corresponding countermeasures can be timely taken. The shut-off device is used, for example, in a facility for the production of phthalic anhydride (PSA) with the aim of preventing mixtures of explosible gases from penetrating into those parts of the facility to be protected. |