Foam generator for papermaking machine

Claim 2

A dispersing and mixing unit for a paper making machine comprising in combination: an upstream conduit for conducting delivered liquid; a downstream conduit for receiving and conducting the liquid after being mixed with a material; means defining a mixing and dispersing chamber connected between said conduits and having opposed walls with at least one wall having corrugations extending laterally of the flow direction to define a series of constriction and expansion locations in the flow path through the mixing chamber whereby material is dispersed in the liquid in said expansion locations; means for delivering material to be dispersed in the liquid connected to said upstream conduit; and a movable forming surface for receiving liquid from the downstream conduit to form a fibrous web on the forming surface.

Claim 3

A dispersing and mixing unit for a paper making machine constructed in accordance with claim 1: wherein said chamber contains a plug and said plug is a teardrop shaped with a downstream section of decreasing dimension so that an expansion zone is formed adjacent the downstream surfaces of the plug.

Claim 4

A dispersing and mixing unit for a paper making machine constructed in accordance with claim 2: including means for adjustably changing the position of the plug in the chamber in the direction of liquid flow.

Claim 5

A dispersing and mixing unit for a paper making machine constructed in accordance with claim 1: wherein the liquid flowing through the conduits and chamber is a surfactant foam, and said means for delivering the material injects a controlled amount of air or fibers into the foam for uniform foam generation and fiber distribution within said dispersion portion.

Claim 6

A dispersing and mixing unit for a paper making machine constructed in accordance with claim 1: wherein both opposing walls of said dispersing chamber have corrugations extending laterally of the flow with the peaks of the corrugations being generally in alignment on opposing walls.

Claim 7

A dispersing and mixing unit for a paper making machine constructed in accordance with claim 5: including means for moving said walls relatively in a direction toward or away from each other to change the size of the expansion locations.

Claim 8

A dispersing and mixing unit for a paper making machine constructed in accordance with claim 5: wherein said mixing and dispersing chamber is formed within a housing having one of said walls; and a movable plug located in said housing providing the other of said walls with the plug having said corrugations on an upstream side facing corrugations on the housing wall.

Claim 9

A dispersing and mixing unit for a paper making machine in a mechanism for forming a fibrous web by depositing fibers out of a liquid foam suspension comprising in combination: means defining a flow path including an upstream conduit for conducting a delivered foam liquid; a pressure pump for driving the foam liquid through said flow path; a headbox with a slice chamber with a slice opening; a movable forming surface positioned to receive the foam liquid from the slice opening with a fibrous web forming on the forming surface; a dispersing and mixing chamber positioned in the flow path receiving liquid from the upstream conduit and connected to deliver the liquid to the headbox including a plug positioned in said mixing chamber defining a flow path between the chamber wall and plug which path forms a venturi with a venturi constriction and a venturi expansion portion with the expansion portion of the venturi generating a distribution and dispersion pattern in the foam liquid; means for delivering a surfactant foam to said pump; means for mixing fibers in said foam; and means having an opening into said upstream conduit for delivering a controlled amount of air to said foam in advance of the venturi for ingestion of the air into the foam in the mixing chamber.

Claim 10

A dispersing and mixing unit for a paper making machine in a mechanism for forming a fibrous web by depositing fibers out of a liquid foam suspension comprising in combination: means defining a flow path including an upstream conduit for conducting a delivered foam liquid; a pressure pump for driving the foam liquid through said flow path; a headbox with a slice chamber with a slice opening; a movable forming surface positioned to receive the foam liquid from the slice opening with a fibrous web forming on the forming surface; a dispersing and mixing chamber positioned in the flow path receiving liquid from the upstream conduit and connected to deliver the liquid to the headbox including a plug positioned in said mixing chamber defining a flow path between the chamber wall and plug which path forms a venturi with a venturi constriction and a venturi expansion portion with the expansion portion of the venturi generating a distribution and dispersion pattern in the foam liquid; means for delivering a surfactant foam to said pump; means for mixing fibers in said foam; and means having an opening into said upstream conduit for delivering a controlled amount of air to said foam in advance of the venturi for ingestion of the air into the foam in the mixing chamber.

Claim 11

A dispersing and mixing unit for a paper making machine in a mechanism for forming a fibrous web by depositing fibers out of a liquid suspension constructed in accordance with claim 8: including means for adjusting the position of said plug upstream or downstream in the direction of flow to vary the shape of said venturi.

Claim 12

A dispersing and mixing unit for a paper making machine constructed in accordance with claim 9: wherein said means for delivering the air includes passage means leading into said plug with release openings in the plug surface for discharge into the housing chamber.