| 摘要 |
The invention concerns the cleaning of the granulate filter bed material of a gas filter. The granulate material is contained in the spaces between two or more gas-permeable walls. The walls are designed as vertical tubes which may be cylindrical or consist of two cones with their bases together. The crude gas passes transversely through these walls from an outer chamber into an inner chamber from where it is led away as purified gas. A transfer pipe runs from the bottom of the filter bed to the top. A current of conveyor air is forced through the transfer pipe so that it carries the granulate material from the bottom to the top of the filter bed. At the top of the filter bed the conveyor air escapes through a gas-permeable hood while the granulate material falls into the space(s) between the gas-permeable walls, passes down between the walls and eventually reaches the bottom of the filter bed again. This circulation of the filter bed material by means of the conveyor gas passing through the transfer pipe can take place during a separate cleaning phase or at the same time as filtration. Provision is also made for passing blasts for scavenging air through the filter bed in the opposite direction to that of the crude gas flow in order to remove filter cake adhering to the outside surface of the outer gas-permeable wall.
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