US3743252A — Air cooled extruder

Claim 1

Independent Claim 140 words

In an extruder comprising a metal barrel having a longitudinal axis and containing an extruder screw for mixing and pressurizing molten resin within the confines of said barrel, external metal heat conducting fins transverse to said axis, extending about said barrel, and means defining an air flow path for cooling air over said fins, said path being generally perpendicular to the longitudinal axis of said barrel, the improvement wherein said heat-conducting fins are performed, each having an aperture corresponding generally in shape to, but having an unstressed shape smaller than, a respective peripheral barrel portion to which it is attached, said fins being heatshrunk about said portion into pressure applying intimate heat transfer relation therewith, the apparatus effective to transfer heat from said resin through said barrel and through said shrunk fit joint and fin to air in said path.

Claim 2

Dependent Claim 140 words

In an extruder comprising a metal barrel having a longitudinal axis and containing an extruder screw for mixing and pressurizing molten resin within the confines of said barrel, external metal heat conducting fins transverse to said axis, extending about said barrel, and means defining an air flow path for cooling air over said fins, said path being generally perpendicular to the longitudinal axis of said barrel, the improvement wherein said heat-conducting fins are performed, each having an aperture corresponding generally in shape to, but having an unstressed shape smaller than, a respective peripheral barrel portion to which it is attached, said fins being heatshrunk about said portion into pressure applying intimate heat transfer relation therewith, the apparatus effective to transfer heat from said resin through said barrel and through said shrunk fit joint and fin to air in said path.

Claim 3

Dependent Claim 36 words

The apparatus as claimed in claim 1 wherein each fin has a greater effective surface area in the air flow path on the downstream side of said barrel than on the upstream side of said barrel.

Claim 4

Dependent Claim 38 words

The apparatus as claimed in claim 1 wherein said fins are formed of planar plates, downstream portions of each fin being bent from the general plane of said fin into turbulence-producing position, resultant turbulence contributing to cooling efficiency.

Claim 5

Dependent Claim 19 words

The apparatus as claimed in claim 3 wherein downstream corner portions of said fin are bent along straight lines.

Claim 6

Dependent Claim 41 words

The apparatus as claimed in claim 1 wherein the portions of said fins contacting said barrel are spaced apart longitudinally and heaters are disposed between neighboring pairs of said fins, said heaters being disposed in heat transfer relation to said barrel.

Claim 7

Dependent Claim 35 words

The apparatus as claimed in claim 1 including heat flow restricting openings in the upstream portion of said fins effective to reduce the heat transfer between said upstream fin portions and the adjacent barrel surface.

Claim 8

Dependent Claim 44 words

Apparatus as claimed in claim 6 wherein said heat flow restricting openings of a fin comprise relieved areas of said fin at said aperture on the upstream side of said fin, the fin at said relieved areas being out of contact with said barrel.

Claim 9

Dependent Claim 31 words

Apparatus as claimed in claim 7 wherein said relieved areas comprise a plurality of spaced apart arcuate formations in said fin, of radius smaller than the general radius of said aperture.

Claim 10

Dependent Claim 30 words

Apparatus as claimed in claim 8 wherein said plurality of relieved areas extends approximately one third of the distance around the periphery of said aperture, on the upstream side thereof.

Claim 11

Dependent Claim 92 words

The apparatus as claimed in claim 1 wherein a said fin is thicker adjacent said barrel than at locations spaced from said barrel thereby providing an outwardly facing surface on said fin; and retaining means engaging each said surface comprising a hoop disposed upon said surface and substantially surrounding said barrel, said hoop effective to maintain said metal-to-metal contact of said fin and barrel despite tendency in the absence of said hoop for said fin aperture to be permanently enlarged due to fin deformation beyond its elastic limit under certain thermal conditions.

Claim 12

Dependent Claim 14 words

The apparatus as claimed in claim 10 wherein each said hoop comprises high-strength steel.

Claim 13

Dependent Claim 17 words

The apparatus as claimed in claim 11 wherein said barrel comprises steel and said fins comprise aluminum.

Claim 14

Dependent Claim 18 words

The apparatus as claimed in claim 1 wherein said barrel comprises steel and said fins comprise silver-bearing copper.

Claim 15

Dependent Claim 157 words

In an extruder comprising an elongated barrel in which a screw works and extrudes plastic, the extruder having a cooling system comprising a series of transverse cooling fins secured to the exterior of the barrel, a blower and ducting arranged to cause A forced flow of air past said fins and damper means for regulating said air flow, the improvement wherein said ducting includes a duct portion adjacent said barrel having an elongated cross-section in the direction parallel to said barrel and said damper means comprising a multiplicity of individually operable dampers arranged in series to extend end-to-end across the long dimension of said cross-section, the dampers and the respective portions of the air flow path defined by said ducting communicating with respective portions of said barrel whereby varying air flow rates and attendant varying cooling effect along the length of said barrel can be achieved by varying the settings of various of said plurality of dampers.

Claim 16

Dependent Claim 157 words

In an extruder comprising an elongated barrel in which a screw works and extrudes plastic, the extruder having a cooling system comprising a series of transverse cooling fins secured to the exterior of the barrel, a blower and ducting arranged to cause A forced flow of air past said fins and damper means for regulating said air flow, the improvement wherein said ducting includes a duct portion adjacent said barrel having an elongated cross-section in the direction parallel to said barrel and said damper means comprising a multiplicity of individually operable dampers arranged in series to extend end-to-end across the long dimension of said cross-section, the dampers and the respective portions of the air flow path defined by said ducting communicating with respective portions of said barrel whereby varying air flow rates and attendant varying cooling effect along the length of said barrel can be achieved by varying the settings of various of said plurality of dampers.

Claim 17

Dependent Claim 13 words

The extruder of claim 14 wherein said dampers comprise plates mounted in slides.

Claim 18

Dependent Claim 47 words

Apparatus as claimed in claim 14 including a plurality of cooling fins in heat transfer relation with said barrel, at least a portion of said fins having a greater effective surface area on the downstream side of said barrel than on the upstream side of said barrel.

Claim 19

Dependent Claim 120 words

In an extruder comprising a metal barrel having a longitudinal axis and containing an extruder screw for mixing and pressurizing molten resin within the confines of said barrel, external metal heat-conducting fins transverse to said axis, extending about said barrel, and means defining an air flow path for cooling air over said fins, said path being generally perpendicular to the longitudinal axis of said barrel, the improvement wherein said heat-conducting fins are preformed of metal plate, said fins having a pair of straight parallel sides in alignment with said barrel and a pair of inwardly converging straight sides extending therebeyond in the direction of air flow and said straight sides conforming substantially to planar walls forming said air flow path.

Claim 20

Dependent Claim 120 words

In an extruder comprising a metal barrel having a longitudinal axis and containing an extruder screw for mixing and pressurizing molten resin within the confines of said barrel, external metal heat-conducting fins transverse to said axis, extending about said barrel, and means defining an air flow path for cooling air over said fins, said path being generally perpendicular to the longitudinal axis of said barrel, the improvement wherein said heat-conducting fins are preformed of metal plate, said fins having a pair of straight parallel sides in alignment with said barrel and a pair of inwardly converging straight sides extending therebeyond in the direction of air flow and said straight sides conforming substantially to planar walls forming said air flow path.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1976-07-02	1977-01-01	1977-07-03	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1980-07-02	1981-01-01	1981-07-03	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1984-07-02	1985-01-01	1985-07-03	$7700.00	Window Closed / Lapsed

Air cooled extruder

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