Device for the injection of fluid foaming agents into plasticized polymeric material

Claim 1

A device for the injection of a fluid foaming agent into a plasticized polymeric material comprising a housing defining an axially elongated conduit for the passage of said polymeric material therethrough, at least two diffusion plates fixed in the conduit to extend substantially normal to the axis of the conduit, said two plates including a first diffusion plate of sintered material having axial perforations therethrough arranged in a grid pattern, and internal fluid distribution ducts within the plate and communicating with the periphery of the plate, and a second diffusion plate of sintered material having axial perforations therethrough arranged in a grid pattern which is offset with respect to the grid pattern of said first diffusion plate, said second diffusion plate also having internal fluid distribution ducts communicating with the periphery of said second diffusion plate, and supply means for conducting said fluid through said housing into communication with the peripheries of the diffusion plates.

Claim 2

A device for the injection of a fluid foaming agent into a plasticized polymeric material comprising a housing defining an axially elongated conduit for the passage of said polymeric material therethrough, at least two diffusion plates fixed in the conduit to extend substantially normal to the axis of the conduit, said two plates including a first diffusion plate of sintered material having axial perforations therethrough arranged in a grid pattern, and internal fluid distribution ducts within the plate and communicating with the periphery of the plate, and a second diffusion plate of sintered material having axial perforations therethrough arranged in a grid pattern which is offset with respect to the grid pattern of said first diffusion plate, said second diffusion plate also having internal fluid distribution ducts communicating with the periphery of said second diffusion plate, and supply means for conducting said fluid through said housing into communication with the peripheries of the diffusion plates.

Claim 3

A device for the injection of a fluid foaming agent into a plasticized polymeric material comprising a housing defining an axially elongated conduit for the passage of said plasticized polymeric material therethrough, a plurality of axially abutting diffusion plates extending across the conduit to lie substantially normal to the axis of the conduit, each of said diffusion plates having axial perforations therethrough arranged in grid patterns, the grid patterns of axially adjacent plates being offset relative to one another to define an overall labyrinth flow path through the plates, said plates each having a peripheral flow passage and transverse fluid distribution ducts communicating with the peripheral flow passage and extending across the transverse extent of the plaTe intermediate the perforations therein, and means for supplying said fluid foaming agent to the peripheral flow passages of said plates.

Claim 4

A device for the injection of a fluid foaming agent into a plasticized polymeric material comprising a housing defining an axially elongated conduit for the passage of said plasticized polymeric material therethrough, a plurality of axially abutting diffusion plates extending across the conduit to lie substantially normal to the axis of the conduit, each of said diffusion plates having axial perforations therethrough arranged in grid patterns, the grid patterns of axially adjacent plates being offset relative to one another to define an overall labyrinth flow path through the plates, said plates each having a peripheral flow passage and transverse fluid distribution ducts communicating with the peripheral flow passage and extending across the transverse extent of the plaTe intermediate the perforations therein, and means for supplying said fluid foaming agent to the peripheral flow passages of said plates.

Claim 5

A device for injection of a fluid foaming agent into a plasticized polymeric material comprising a housing defining a conduit for the passage of said polymeric material therethrough, a structurally strong perforate support plate traversing the conduit in fixed relation therewith wherein the perforations are in a grid pattern of regular pitch; a porous element in the conduit in series with the said support plate comprising, a first diffusion plate of sintered material having perforations coextensive with the perforations in said support plate wherein said perforations are countersunk to a point of contiguity in a surface remote from the support plate and having fluid distribution ducts within the plate, and a second diffusion plate of sintered material having perforations on a grid pattern which is offset one-half pitch with respect to the grid pattern of said first plate wherein said perforations are countersunk to a point of contiguity in both surfaces of the plate and having fluid distribution ducts within the plate; means for retaining the said porous element within the conduit, and supply means for the distribution of said fluid peripherally within the housing to the porous element.

Claim 6

A device for injection of a fluid foaming agent into a plasticized polymeric material comprising a housing defining a conduit for the passage of said polymeric material therethrough, a structurally strong perforate support plate traversing the conduit in fixed relation therewith wherein the perforations are in a grid pattern of regular pitch; a porous element in the conduit in series with the said support plate comprising, a first diffusion plate of sintered material having perforations coextensive with the perforations in said support plate wherein said perforations are countersunk to a point of contiguity in a surface remote from the support plate and having fluid distribution ducts within the plate, and a second diffusion plate of sintered material having perforations on a grid pattern which is offset one-half pitch with respect to the grid pattern of said first plate wherein said perforations are countersunk to a point of contiguity in both surfaces of the plate and having fluid distribution ducts within the plate; means for retaining the said porous element within the conduit, and supply means for the distribution of said fluid peripherally within the housing to the porous element.