Apparatus for replacing a filter cartridge mounted in a fluid flow conduit

摘要

The filter can be retracted from the pipe through an opening (8) in the pipe wall, and placed in a pocket (14) which is folded when not in use. The pocket is slightly longer than the cartridge. The cap covering the opening is in two parts (10,12), each fixed to one end of the pocket when it is open and the second part is also fixed to the edge (7) of the opening. Both parts of the cap have a union (11,12) around their open end and the two can be fixed together. The union on the second cap can be fixed to the edge of the opening in the pipe wall. A valve (21) closes the opening in the pipe wall after the cartridge is removed. The valve is operated automatically as the cartridge is removed. The part of the cartridge which is opposite to that fixed to the cap has a means of closing the pocket after the cartridge is fitted into it. The first, hollow part of the cap has a tensioning device, e.g. a handle, allowing it to be removed from the pipe after it is detached from the second part of the cap which stays fixed to the opening. The pocket is designed to unfold as the cartridge is retracted and it refolds into the hollow part of the cap.