Filter bag retaining system with removable thimble extension

DETAILED DESCRIPTION I claim as my invention: 1.
In an apparatus for filtering particulate matter from a gaseous stream including a plenum having a wall provided with an aperture therein and said wall defining a raw gas chamber having a gas inlet opening and a filtered gas chamber having a gas outlet opening, a thimble secured to said wall and surrounding said aperture, an inwardly-inclined flange formed in the upper peripheral portion of said thimble, a vertically-extending tubular filter bag secured to said thimble and in flow-through communication with said plenum and extending into said filtered gas chamber, and a removable annular insert fitted into the interior of said thimble and having a portion which extends beneath the body of the thimble into said raw gas chamber such that gas flowing along said wall must flow downwardly and then upwardly through said annular insert before passing into said filter bag, said annular insert having an outwardly-flared flange portion at its upper periphery which rests on said first-mentioned flange.
2.
The apparatus of claim 1 wherein said annular insert is in close abutting relationship with the inner periphery of said thimble.
3.
The apparatus of claim 2 wherein said annular insert is constructed and arranged such that it is retained within said thimble by its own weight without the use of auxiliary fastening elements.
4.
The apparatus of claim 1 wherein said gas inlet opening is positioned so as to direct air into the plenum such that at least part of said air flows along said wall.




Description:
BACKGROUND OF THE INVENTION As is known, baghouses are used extensively in power generating stations and the like for air pollution control.
In a baghouse of this type, dust-laden air enters a plenum chamber and then flows upwardly through apertures in an upper wall of the plenum chamber and into a plurality of vertically-elongated tubular filter bags which separate the dust from the air as it flows through the fabric walls of the bags.
The bottom of each filter bag is open and is secured to the periphery of a thimble which extends upwardly from the upper wall of the plenum chamber and surrounds an associated one of the aforesaid apertures