Internally reinforced extruded plastic pipe

Claim 2

An internally reinforced pipe for use in a buried environment comprising extruded synthetic resin thermoplastic having a modulus of elasticity no less than about 35,000 p.s.i., the pipe having wall means, defining the external shape of the pipe and internal reinforcing plate means having opposite ends thereof integrally formed with the wall means at connections thereto, the connections forming end contraints for the reinforcing plate means and said reinforcing plate means extending generally in a plane between said connections for substantially the full length of the pipe, said connections and the reinforcing plate means designed whereby to cooperatively act so that the design loading strength of the pipe is defined by the critical buckling strength of said reinforcing plate means so that when the pipe is used in buried environments the pipe provides a greatest resistance to loading failure upon orienting the plate means substantially parallel to the direction of maximum loading along the pipe whereby the critical mode of pipe failure is by buckling of the plate means rather than solely by deflection of the wall means and wherein said pipe exhibits semi-rigid response characteristics to loading therealong.

Claim 3

An internally reinforced pipe as in claim 1 wherein the wall means is circular in cross-section.

Claim 4

An internally reinforced pipe as in claim 2 wherein said reinforcing plate means extends radially of the circular wall means.

Claim 5

An internally reinforced pipe as in claim 1 wherein the wall means includes non-circular curved wall portions in cross-section.

Claim 6

An internally reinforced pipe as in claim 1 wherein the connections include integral fillet means along both sides of the reinforcing plate means.

Claim 7

An internally reinforced pipe as in claim 1 wherein the wall means includes two opposing parallel wall portions, said reinforcing plate means being spaced therebetween and arranged generally parallel thereto.

Claim 8

An internally reinforced pipe as in claim 1 wherein said wall means includes spaced-apart openings therethrough.

Claim 9

An internally reinforced pipe as in claim 7 wherein the openings are located along said wall means at both sides of each plate means connection thereto.

Claim 10

An internally reinforced pipe as in claim 8 wherein the openings are spaced apart at regular intervals along the pipe.

Claim 11

An internally reinforced pipe as in claim 9 wherein the openings are formed in linear rows extending lengthwise of the pipe for substantially the full length thereof.

Claim 12

An internally reinforced pipe as in claim 1 wherein the reinforcing plate means has a thickness no less than the thickness of the wall means.

Claim 13

An internally reinforced pipe as in claim 1 wherein said plate means generally defines a plane and said pipe being symmetric about said plane.

Claim 14

An internally reinforced pipe as in claim 1 wherein said plate means and wall means form at least two pipe chambers extending for substantially the full length of the pipe.

Claim 15

An internally reinforced pipe as in claim 1 wherein said pipe includes a plurality of parallel spaced-apart reinforcing plate means.

Claim 16

A semi-rigid pipe for use in buried environments comprising an extrusion of synthetic resin thermoplastic material having a modulus of elasticity no less than 35,000 p.s.i., outer wall means and internal reinforcing plate means having ends thereof integrally connected to the wall means, said plate means being arranged generally in a plane between said connections, the connections forming end constraints for the plate means, said pipe intended to be oriented with the reinforcing plate means generally parallel to the direction of a maximum loading acting along the pipe for achieving greatest resistance to loading failure, the connections and the plate means designed whereby to cooperatively set under loading so that the loading capacity of the pipe is determined by the critical buckling strength of the plate means wherein the critical mode of pipe failure is by buckling of the reinforcing plate means and the pipe exhibits semi-rigid response to loading.

Claim 17

A semi-rigid pipe for use in buried environments comprising an extrusion of synthetic resin thermoplastic material having a modulus of elasticity no less than 35,000 p.s.i., outer wall means and internal reinforcing plate means having ends thereof integrally connected to the wall means, said plate means being arranged generally in a plane between said connections, the connections forming end constraints for the plate means, said pipe intended to be oriented with the reinforcing plate means generally parallel to the direction of a maximum loading acting along the pipe for achieving greatest resistance to loading failure, the connections and the plate means designed whereby to cooperatively set under loading so that the loading capacity of the pipe is determined by the critical buckling strength of the plate means wherein the critical mode of pipe failure is by buckling of the reinforcing plate means and the pipe exhibits semi-rigid response to loading.

Claim 18

In an extruded synthetic resin thermoplastic pipe section having wall means defining the external boundary of the pipe, the improvement comprising integral reinforcing means, said reinforcing means comprising at least one generally plate-like stem having ends integrally formed with the wall means at connections thereto, the connections being end constraints for the stem, the stem extending for substantially the full length of the pipe section, whereby the pipe section is capable of being oriented to dispose the stem parallel to the direction of maximum stress to be imposed in a buried environment, said stem and connections being sized and formed to cooperatively act under loading to provide a critical buckling strength of said stem, said pipe characterized by having a design loading strength defined by the critical buckling strength of said stem whereby said pipe behaves semi-rigidly to loading and the critical mode of failure is by stem buckling rather than deflection of the wall means alone, said stem forming at least two pipe chambers, each chamber having a different portion of the wall means forming a boundary thereof, whereby said wall means is thereby capable of including openings to enable each chamber to communicate exteriorly of the pipe section through openings opening thereto.

Claim 19

In an extruded synthetic resin thermoplastic pipe section having wall means defining the external boundary of the pipe, the improvement comprising integral reinforcing means, said reinforcing means comprising at least one generally plate-like stem having ends integrally formed with the wall means at connections thereto, the connections being end constraints for the stem, the stem extending for substantially the full length of the pipe section, whereby the pipe section is capable of being oriented to dispose the stem parallel to the direction of maximum stress to be imposed in a buried environment, said stem and connections being sized and formed to cooperatively act under loading to provide a critical buckling strength of said stem, said pipe characterized by having a design loading strength defined by the critical buckling strength of said stem whereby said pipe behaves semi-rigidly to loading and the critical mode of failure is by stem buckling rather than deflection of the wall means alone, said stem forming at least two pipe chambers, each chamber having a different portion of the wall means forming a boundary thereof, whereby said wall means is thereby capable of including openings to enable each chamber to communicate exteriorly of the pipe section through openings opening thereto.

Claim 20

An internally reinforced pipe comprising extruded synthetic resin thermoplastic material intended for use in buried environments and surcharged buried environments, said pipe having a modulus of elasticity of no less than 35,000 p.s.i. and exhibiting semi-rigid behavior during loading, the pipe substantially eliminating reliance upon surrounding media for resistance to loading, wherein buckling of internal reinforcement means, rather than pipe wall deflection alone, is the critical mode of failure, said pipe having wall means defining the outer shape of the pipe and the internal reinforcement means comprising at least one reinforcing plate having opposing long ends thereof being integrally formed with the wall means at connections thereto and thereby forming at least two separate pipe chambers, each chamber having a different portion of the wall means as a boundary thereof, the connections to the wall means forming end contraints for the reinforcing plate, for achieving greatest resistance to loading failure, said pipe to be buried having said reinforcing plate oriented parallel to the direction of a maximum loading on the pipe, wherein said connections and reinforcing plate are formed to cooperatively act under loading to achieve a critical buckling strength for the plate that is the maximum loading strength of the pipe.

Claim 21

An internally reinforced pipe comprising extruded synthetic resin thermoplastic material intended for use in buried environments and surcharged buried environments, said pipe having a modulus of elasticity of no less than 35,000 p.s.i. and exhibiting semi-rigid behavior during loading, the pipe substantially eliminating reliance upon surrounding media for resistance to loading, wherein buckling of internal reinforcement means, rather than pipe wall deflection alone, is the critical mode of failure, said pipe having wall means defining the outer shape of the pipe and the internal reinforcement means comprising at least one reinforcing plate having opposing long ends thereof being integrally formed with the wall means at connections thereto and thereby forming at least two separate pipe chambers, each chamber having a different portion of the wall means as a boundary thereof, the connections to the wall means forming end contraints for the reinforcing plate, for achieving greatest resistance to loading failure, said pipe to be buried having said reinforcing plate oriented parallel to the direction of a maximum loading on the pipe, wherein said connections and reinforcing plate are formed to cooperatively act under loading to achieve a critical buckling strength for the plate that is the maximum loading strength of the pipe.

Claim 22

An internally reinforced pipe as claimed in claim 17 wherein said pipe comprises a plurality of parallel spaced-apart reinforcing plates.

Claim 23

An internally reinforced pipe as claimed in claim 17 wherein said pipe includes collection means comprising openings through said wall means arranged at locations therealong whereby each said chamber communicates exteriorly of the pipe through openings opening thereto.

Claim 24

An internally reinforced pipe for use in buried environments having substantially isotropic loading forces acting around the pipe, said pipe comprising an extruded synthetic resin thermoplastic material having a modulus of elasticity of no less than 35,000 p.s.i., outer wall means being circular in cross section, a plurality of radial internal reinforcing stems having ends thereof integrally formed with the wall means at connections thereto, said stems each extending generally in a plane between a pair of connections, the connections forming end constraints for the stems, said stems co-extending for substantially the full length of the pipe, the reinforcing stems forming a plurality of substantially equal-sized pipe chambers, each said chamber having a separate portion of the wall means as a boundary thereof, and said reinforcing stems and connections therefor designed to cooperatively act under loading to provide a critical buckling strength for the stems, said pipe having a design loading strength defined by said critical buckling strength for generally isotropic loading around the pipe, whereby said pipe exhibits semi-rigid response to said loading and substantially eliminates reliance on surrounding backfill media to resist failure.

Claim 25

An internally reinforced pipe for use in buried environments having substantially isotropic loading forces acting around the pipe, said pipe comprising an extruded synthetic resin thermoplastic material having a modulus of elasticity of no less than 35,000 p.s.i., outer wall means being circular in cross section, a plurality of radial internal reinforcing stems having ends thereof integrally formed with the wall means at connections thereto, said stems each extending generally in a plane between a pair of connections, the connections forming end constraints for the stems, said stems co-extending for substantially the full length of the pipe, the reinforcing stems forming a plurality of substantially equal-sized pipe chambers, each said chamber having a separate portion of the wall means as a boundary thereof, and said reinforcing stems and connections therefor designed to cooperatively act under loading to provide a critical buckling strength for the stems, said pipe having a design loading strength defined by said critical buckling strength for generally isotropic loading around the pipe, whereby said pipe exhibits semi-rigid response to said loading and substantially eliminates reliance on surrounding backfill media to resist failure.

Claim 26

An internally reinforced pipe as claimed in claim 20 wherein said pipe is capable of use as a collection pipe and includes openings through said wall means, each said pipe chamber associating with openings opening thereto.