Method and apparatus for bag collection of dirt

Claim 2

A method as defined in claim 2, wherein said bags are close together, said pressurized fluid is introduced under pressure near the top of said inner bag, and said collapse of said inner bag travels from the top thereof downwardly.

Claim 3

A method as defined in claim 2, including the step of stopping said passing of said stream of fluid containing dust particles in said first direction through said bags prior to creating said pressurized fluid differential between said bags.

Claim 4

A method as defined in claim 1, wherein there are a plurality of units, each comprising two of said closely adjacent filter media, a dirt hopper below said units, said method including the step of applying said pressurized fluid against the downstream surface of said upstream filter medium of one of said units while continuing to operate another of said units in a dirt collecting manner.

Claim 5

Apparatus for the collection of dirt entrained in a fluid stream, comprising a housing, an upstream elongated permeable bag suspended vertically in said housing, said bag closed at one end and open at the other, a downstream elongated permeable tubular filter medium mounted in said housing spaced from said bag concentric with and closely adjacent said upstream bag for substantially the entire length of said bag, said bag and filter medium being free of mutual attachment over substantially their entire dirt collecting surfaces sufficiently to permit flow of fluid between said two filter media from end to end thereof, there being an inlet for a dirty fluid stream in said housing and a passageway connected with and communicating directly between the inlet and with the open end of said upstream bag, means sealing said dirty stream from said downstream filter medium and from said passageway except through said upstream bag, said housing enclosing the space outside of said bag and said filter medium, there being an outlet for cleaned fluid communicating with said housing space downstream of said tubular filter medium, means for creating a pressure differential between said inlet and said outlet to cause a dirt collecting fluid flow to pass between them, means for intermittingly creating a fluid pressure between said bag and said tubular filter medium including a passageway connected with and communicating between a source of pressure fluid and said space between said bag and said tubular filter medium sufficient to penetrate said bag usptream to thereby remove dirt collected on the upstream surface of said bag so that it falls downwardly, and means for discharging said removed dirt finally from the lower end of said housing.

Claim 6

Apparatus as defined in claim 6, wherein said means for creating a pressure differential between said inlet and said outlet comprises a blower in communication with said outlet, and said means for creating a gas pressure between said bag and said filter medium comprises an opening to atmosphere communicating with the space between said bag and said filter medium and means for opening and closing said last named opening.

Claim 7

Apparatus as defined in claim 6, wherein said upstream bag is of heat resistant material such as fiber glass cloth, and said filter medium is a heat resistant gas-permeable solid such as sintered metal or porous ceramic.

Claim 8

Apparatus as defined in claim 6, wherein said filter medium is a second bag outside of said upstream bag.

Claim 9

Apparatus as defined in claim 9, wherein said means for creating a fluid pressure between said bags includes blower meanS and a blow-down passageway communicating from said blower means to the space between said bags near the top of said upstream bag, together with means for controlling said blower and the flow in said blow-down passageway.

Claim 10

Apparatus as defined in claim 10, wherein said blower means is reversible as to direction of rotation having positive and negative pressure ports respectively changing upon blower means reversal, one of said ports communicating by a first passageway common to said blow-down passageway and to said clean fluid outlet, the other of said ports communicating by a second passageway to a clean fluid disposal point, and a check valve in said clean fluid outlet opening only toward said blower means and a check valve in said blow-down passageway opening only toward said space between said bags, whereby rotation of said blower means in a first direction causes suction at said clean fluid outlet without any effect on said blow-down passageway and reversal of rotation of said blower means in a second direction cuts off suction at said clean fluid outlet, while creating said fluid pressure between said bags.

Claim 11

Apparatus for collection of finely divided particles entrained in a dirty fluid stream, comprising a frame, upstream and downstream filter members suspended in said frame, said members being of sleeve shape and spaced one inside of the other, said upstream and downstream filter members being free of mutual attachment over substantially their entire dirt collecting surfaces sufficiently to permit flow of fluid between said two filter members from end to end thereof, means including structural members fixed and associated between said frame and said filter members for permitting direct access of a dirty fluid stream only to the upstream surface of said upstream filter member and access of said dirty fluid stream to said upstream face of said downstream filter member only through said upstream member, means whereby application of a pressure differential between said upstream face of said upstream filter member and said downstream face of said downstream filter member will cause passage of said stream serially through said upstream and downstream filter members in that order, whereby to collect said particles on the upstream surface of said upstream member, and means for intermittingly applying a pressurized fluid between said filter members including a passageway connected with and communicating between a source of pressure fluid and said space between said sleeve shape filter members to cause a pressure against the downstream surface of said upstream filter member sufficient to dislodge a major portion of said collected particles from said upstream surface of said upstream filter member.

Claim 12

Apparatus as defined in claim 12, wherein said upstream filter member in use is more flexible than said downstream member, and said upstream member is inside said downstream member.

Claim 13

Apparatus as defined in claim 12, wherein said upstream filter member in use is more flexible than said downstream member, and said upstream member is outside said downstream member.

Claim 14

Apparatus as defined in claim 12 wherein said upstream filter member has a greater permeability with respect to said pressurized fluid than said downstream filter member.