Apparatus for bending thermoplastic pipes

Claim 2

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and which comprises heat-transfer means for controllably heating and cooling such a pipe, means for locating one end of the pipe in a fixed position externally of said heat-transfer means, means for internally reinforcing the pipe including an inflatable container adapted to be lowered into the pipe and to be inflated to a pressure sufficient to cause said container to abut the pipe so as to provide a reinforcement therefor while suspended therein and means for lowering and raising said container into and out of the pipe when said container is in its normal deflated condition, and means for applying a bending force to said pipe while said pipe is received in said heattransfer means with said one end in said fixed position, the heat-transfer means being adapted to pivot as the pipe is being bent by actuation of the bending force-applying means.

Claim 3

The apparatus according to claim 1, which also comprises means for applying direct heat to the internal walls of the pipe.

Claim 4

The apparatus according to claim 1, wherein the inflatable container is weight-loaded.

Claim 5

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and which comprises a heat transfer means for controllably heating and cooling such a pipe, said means including a jacket of substantially U-shaped cross-section adapted to surround, while spaced from, pipe to form internal heat-transfer medium-conveying surface and nozzles fixed at the base of the U-shaped jacket for supplying heat-transfer medium to be directed at the pipe and to be led by said surfaces to effect the controlled heating and cooling of the pipe, said internal heat-transfer medium-conveying surfaces defining with the pipe narrow gaps at a transition zone intermediate one side portion of the pipe facing said nozzles and another side portion facing away from said nozzles, said internal surfaces projecting freely outwards a distance beyond said another side portion to form a whirl chamber immediately adjacent the latter, means for locating one end of the pipe in a fixed position externally of said heat-transfer means, and means for internally reinforcing the pipe and means for applying a bending force thereto while said pipe is received in said heat-transfer means with said one end in said fixed position, the heat-transfer means being adaPted to pivot as the pipe is being bent by actuation of the bending force-applying means.

Claim 6

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and which comprises a heat transfer means for controllably heating and cooling such a pipe, said means including a jacket of substantially U-shaped cross-section adapted to surround, while spaced from, pipe to form internal heat-transfer medium-conveying surface and nozzles fixed at the base of the U-shaped jacket for supplying heat-transfer medium to be directed at the pipe and to be led by said surfaces to effect the controlled heating and cooling of the pipe, said internal heat-transfer medium-conveying surfaces defining with the pipe narrow gaps at a transition zone intermediate one side portion of the pipe facing said nozzles and another side portion facing away from said nozzles, said internal surfaces projecting freely outwards a distance beyond said another side portion to form a whirl chamber immediately adjacent the latter, means for locating one end of the pipe in a fixed position externally of said heat-transfer means, and means for internally reinforcing the pipe and means for applying a bending force thereto while said pipe is received in said heat-transfer means with said one end in said fixed position, the heat-transfer means being adaPted to pivot as the pipe is being bent by actuation of the bending force-applying means.

Claim 7

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and which comprises heat-transfer means for controllably heating and cooling such a pipe, means for locating one end of the pipe in a fixed position externally of said heat-transfer means, said latter means including a holder to which the upper end of the pipe can be secured and from which said pipe can then be freely suspended downwards substantially vertically, and means for internally reinforcing the pipe and means for applying a bending force thereto while said pipe is received in said heat-transfer means with said one end in said fixed position, the heat-transfer means being adapted to pivot as the pipe is being bent by actuation of the bending force-applying means.

Claim 8

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and which comprises heat-transfer means for controllably heating and cooling such a pipe, means for locating one end of the pipe in a fixed position externally of said heat-transfer means, said latter means including a holder to which the upper end of the pipe can be secured and from which said pipe can then be freely suspended downwards substantially vertically, and means for internally reinforcing the pipe and means for applying a bending force thereto while said pipe is received in said heat-transfer means with said one end in said fixed position, the heat-transfer means being adapted to pivot as the pipe is being bent by actuation of the bending force-applying means.

Claim 9

The apparatus according to claim 5, wherein the means for internally reinforcing the pipe comprises an inflatable container adapted to be inserted in the lower end of the pipe and to be inflated to a pressure sufficient to cause said container to abut the pipe so as to provide a closing off means for the pipe end and said closed-off pipe having filler material deposited therein.

Claim 10

The apparatus according to claim 6, wherein the filler material is preheated.

Claim 11

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and which comprises a holder for locating the pipe in a fixed position; means for internally reinforcing the pipe; means for applying a bending force to the pipe while a major portion of the pipe is in heated condition; and means for heating and cooling said pipe portion with regulatable differentiated contacting effect along the circumference surface of the pipe; said heating and cooling means comprising a jacket of substantially U-shaped cross-section of sufficient dimension to enclose therein, while spaced therefrom, said major portions of the pipe in unbent as well as in partly and completely bent condition, nozzles located at the base of the U-shaped jacket to direct a flow of heat-transfer medium onto and around the circumference surface of the pipe, whereas the legs of the U-shaped jacket forms internal heat-transfer medium conveying surfaces to convey the flow of medium from said nozzles onto and past the pipe surface, and means for regulating the speed of the heat-transfer medium-flow from said nozzles to involve a regulatable contacting surface of the medium-flow on the pipe surface and thus enabling a corresponding differentiated heat-transfer effect on said pipe surface.

Claim 12

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and which comprises a holder for locating the pipe in a fixed position; means for internally reinforcing the pipe; means for applying a bending force to the pipe while a major portion of the pipe is in heated condition; and means for heating and cooling said pipe portion with regulatable differentiated contacting effect along the circumference surface of the pipe; said heating and cooling means comprising a jacket of substantially U-shaped cross-section of sufficient dimension to enclose therein, while spaced therefrom, said major portions of the pipe in unbent as well as in partly and completely bent condition, nozzles located at the base of the U-shaped jacket to direct a flow of heat-transfer medium onto and around the circumference surface of the pipe, whereas the legs of the U-shaped jacket forms internal heat-transfer medium conveying surfaces to convey the flow of medium from said nozzles onto and past the pipe surface, and means for regulating the speed of the heat-transfer medium-flow from said nozzles to involve a regulatable contacting surface of the medium-flow on the pipe surface and thus enabling a corresponding differentiated heat-transfer effect on said pipe surface.

Claim 13

Apparatus as set forth in claim 8 wherein said means for heating and cooling is pivotably mounted to pivot as the pipe is being bent upon actuation of said means for applying a bending force.

Claim 14

Apparatus as set forth in claim 8 wherein said holder is located at one end of the pipe and externally of said means for heating and cooling.

Claim 15

Apparatus as set forth in claim 8 wherein said conveying surfaces define narrow gaps with the pipe at a transition zone intermediate one side portion of the pipe facing said nozzles and another side portion facing away from said nozzles.

Claim 16

The apparatus according to claim 8, which comprises means for internally reinforcing the pipe in the form of an inflatable container for inflation in the lower end of the pipe to seal off said lower end, together with a filling composition for introduction in the sealed-off pipe.

Claim 17

The apparatus according to claim 12, wherein the filling composition of the reinforcing means comprises material having a specific gravity which is high relative to that of the thermoplastic material of the pipe.

Claim 18

The apparatus according to claim 12, wherein the filling composition is in a preheated condition.

Claim 19

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and Which comprises an upstanding support column, a holder fixed thereto for locating one end of the pipe and from which the pipe is suspended downwards in a substantially vertical position, heat-transfer means pivotally mounted on said holder below said one end of the pipe and for reception of the latter, an abutment member of preselected curvature mounted on said holder and serving as a top for one side portion of the pipe during bending thereof, means for pivoting the heat-transfer means to cause the pipe to bear against the abutment member, means for internally reinforcing the pipe, said heat-transfer means having nozzles for the regulatable supply of pressurised heat-transfer medium and said nozzles being arranged to be directed at a side portion of the pipe opposite said one side portion, internal walls of said heat-transfer means defining one chamber with said opposite side portion of the pipe and a whirl chamber having access to the open air with said one side portion of the pipe as well as defining narrow gaps with portions of the pipe separating said one and said opposite side portions, said gaps providing communication between the chambers and the internal construction of the heat-transfer means being such that by regulation of the pressure and heat content of the heat-transfer medium supplied through the nozzles a temperature differential can be produced between the mutually opposite side portions of the pipe with said opposite side portion being exposed to a more intense heat than said one side portion of the pipe.

Claim 20

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and Which comprises an upstanding support column, a holder fixed thereto for locating one end of the pipe and from which the pipe is suspended downwards in a substantially vertical position, heat-transfer means pivotally mounted on said holder below said one end of the pipe and for reception of the latter, an abutment member of preselected curvature mounted on said holder and serving as a top for one side portion of the pipe during bending thereof, means for pivoting the heat-transfer means to cause the pipe to bear against the abutment member, means for internally reinforcing the pipe, said heat-transfer means having nozzles for the regulatable supply of pressurised heat-transfer medium and said nozzles being arranged to be directed at a side portion of the pipe opposite said one side portion, internal walls of said heat-transfer means defining one chamber with said opposite side portion of the pipe and a whirl chamber having access to the open air with said one side portion of the pipe as well as defining narrow gaps with portions of the pipe separating said one and said opposite side portions, said gaps providing communication between the chambers and the internal construction of the heat-transfer means being such that by regulation of the pressure and heat content of the heat-transfer medium supplied through the nozzles a temperature differential can be produced between the mutually opposite side portions of the pipe with said opposite side portion being exposed to a more intense heat than said one side portion of the pipe.

Claim 21

The apparatus according to claim 14, which comprises means for internally heating the pipe pivotably mounted on the support column above the holder thereby enabling said means to be swung away from the pipe when not in use.

Claim 22

The apparatus according to claim 15, which comprises an inflatable container adapted to be lowered into the pipe and to be inflated to a pressure sufficient to cause said container to abut the pipe so as to provide a reinforcement therefor while suspended therein and means for lowering and raising said container into and out of the pipe when said container is in its normal deflated condition.

Claim 23

The apparatus according to claim 17, wherein the inflatable container is weight-loaded.

Claim 24

The apparatus according to claim 15, which comprises means for internally reinforcing the pipe in the form of an inflatable container for inflation in the lower end of the pipe to seal off said lower end, together with a filling composition for introduction in the sealed-off pipe.

Claim 25

The apparatus according to claim 19, wherein the filling composition of the reinforcing means comprises material having a specific gravity which is high relative to that of the thermoplastic material of the pipe.

Claim 26

The apparatus according to claim 19, wherein the filling composition is in a preheated condition.

Claim 27

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and which comprises an upstanding column, a holder fixed thereto of C-shaped horizontal section permitting lateral location of one end of the pipe while the latter is suspended downwards in a substantially vertical position, heat-transfer means for receiving a major portion of the pipe mounted on said holder below said one end of the pipe and arranged to pivot about a horizontal axis, a curved abutment member mounted on said holder with a substantially convex surface facing the pipe, said member serving as a stop for one side portion of the pipe during bending of the latter, means located at the base of the heat-transfer means for pivoting the latter and for causing, as a result of the bending forces, the pipe to bear against the abutment member, means for internally reinforcing the pipe, said heat-transfer means giving regulatable nozzles directed towards a side portion of the pipe opposite said one side portion, said nozzles being arranged vertically one above the other for the supply of pressurised fluid medium to effect appropriate heaTing and cooling of the pipe and further said heat-transfer means being formed with internal walls extending substantially at right angles to the longitudinal axis of the pipe and for guiding the pressurised fluid medium partially around the pipe and on to the outside air, said walls defining with said pipe on either side thereof first and second chambers adjacent and remote from the nozzles respectively as well as narrow gaps providing communication between said chambers, the internal design of the heat-transfer means being such that on increasing the pressure of hot pressurised fluid medium the nozzle-facing side portion of the pipe is exposed to intense heat which is accompanied by an increasing rate of flow of said hot medium through said gaps thereby increasing a whirl effect in said second chamber and reducing the heating of said one side portion of the pipe.

Claim 28

Apparatus for bending thermoplastic pipes which is capable of functioning as a self-contained unit and which comprises an upstanding column, a holder fixed thereto of C-shaped horizontal section permitting lateral location of one end of the pipe while the latter is suspended downwards in a substantially vertical position, heat-transfer means for receiving a major portion of the pipe mounted on said holder below said one end of the pipe and arranged to pivot about a horizontal axis, a curved abutment member mounted on said holder with a substantially convex surface facing the pipe, said member serving as a stop for one side portion of the pipe during bending of the latter, means located at the base of the heat-transfer means for pivoting the latter and for causing, as a result of the bending forces, the pipe to bear against the abutment member, means for internally reinforcing the pipe, said heat-transfer means giving regulatable nozzles directed towards a side portion of the pipe opposite said one side portion, said nozzles being arranged vertically one above the other for the supply of pressurised fluid medium to effect appropriate heaTing and cooling of the pipe and further said heat-transfer means being formed with internal walls extending substantially at right angles to the longitudinal axis of the pipe and for guiding the pressurised fluid medium partially around the pipe and on to the outside air, said walls defining with said pipe on either side thereof first and second chambers adjacent and remote from the nozzles respectively as well as narrow gaps providing communication between said chambers, the internal design of the heat-transfer means being such that on increasing the pressure of hot pressurised fluid medium the nozzle-facing side portion of the pipe is exposed to intense heat which is accompanied by an increasing rate of flow of said hot medium through said gaps thereby increasing a whirl effect in said second chamber and reducing the heating of said one side portion of the pipe.

Claim 29

The apparatus according to claim 22, wherein one of the internal walls of the heat-transfer means has a portion pivoted about a vertical axis at a position immediately adjacent the side portion of the pipe facing the nozzles and with respect to the remainder of said wall, said pivotable wall portion enabling simultaneous lateral location of the pipe in the C-shaped holder and the heat-transfer means.