Undulating Pipe Manufacture

Abstract

A method for creating lengthwise extending lengths of pipe having an undulating or helical configuration symmetrically formed about a centerline of the pipe includes the steps of heating a sheet of material, feeding the sheet progressively to a succession of stamping stations at which an undulating shape is progressively imparted to the material until at the final station the desired final configuration is achieved in a lengthwise extending half section of the finished pipe, and securing one half section of pipe to another half section of pipe along lengthwise extending edges thereof to form the finished pipe. The undulating pipe of helical configuration finds particular use in the formation of pipelines intended to convey slurries of material such as bituminous material mined from oilsands. Apparatus for carrying out the method is also provided.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a general view of a pipe length having undulations therein, essentially as described in the aforementioned United States published patent application.

FIG. 2 shows the principles of the stamping process according to the present invention.

FIG. 3 shows a side view of an undulating pipe formed in accordance with the invention.

FIG. 4 is an end view of an undulating pipe formed in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a conduit 10 formed to a shape in accordance with the aforementioned United States published patent application. The conduit 10 has a generally circular configuration at any transverse cross-section but in elevation the pipe has an undulating or sinusoidal appearance with sections A, C, E, etc extending vertically above the pipe centerline X, such sections alternating with sections B, D, F, etc extending vertically below the pipe centerline X. Not only are there smooth vertical undulations but there are also horizontal undulations which extend sideways of the centerline and merge smoothly with the vertical undulations giving the pipe or conduit a spiral or helical effect over its length. This spiral shape will achieve the desired flow pattern with the solids of the slurry flowing generally along the center of the pipe without contacting the inner walls of the pipe in the areas of the undulations. It will be appreciated that this configuration will be difficult to manufacture without the efficient process of the present invention.

FIG. 2 illustrates the apparatus of the present invention in a generally schematic manner. A female mould or die half 12 is formed to the desired configuration and is held stationary in the apparatus of the invention. A male mould or die half 14 complementary to the female mould is also formed to the desired configuration and is fixed to the movable portion of a progressive stamping die. A sheet 16 of white hot steel enters the apparatus from one end, moving from one station to the next along the length of the apparatus. At each station a stamping movement is imparted to the movable male portion of the die so that the steel is imparted with a three-dimensional form that progressively, from station to station, takes on the desired configuration of the undulating pipe. It will be appreciated that the undulating form cannot be created with a single stamping as the shape is too complex for a single stamping. However, at each station the material will take on more of the desired shape with each additional stamping movement. At the end of the apparatus the length of material will have the shape of one lengthwise extending half of the length of pipe, either an upper half or a lower half, it being noted that the upper and lower halves will be mirror images of each other.

Once the formed pipe sections have cooled sufficiently the upper and lower halves 18, 20 are brought together and connected along the longitudinal edges thereof as shown in FIG. 3. If there is no need to later separate the upper and lower halves, then they can be welded along the abutting edges of the halves, for example along the seam line 22. That line will follow the undulations. The weld can be created along the outside of the pipe or, if the pipe is of a large diameter, along the inside thereof. As seen in FIG. 4 there will be a naturally formed laterally outwardly extending flange 24 at each edge of the upper and lower halves 18, 20, which flange provides a good base for the weld. Prior to welding it may be necessary to trim the flanges back closer to the upper and lower halves so as to achieve a proper weld without extraneous material being involved.

While FIG. 3 illustrates a weld to connect the sections together it will be appreciated that, as indicated above, other connection mechanisms can be utilized. If the upper and lower sections are to be connected together in a fashion such that they can be separated for the purpose of inspecting the pipeline interior, for repair of a section, or for replacement of a section, then the longitudinally extending joint between the sections should include an appropriate gasket (not shown) to seal the joint as much as possible so as to prevent leakage during operation. With reference again to FIG. 4, it would be possible to secure the upper and lower halves or sections together by passing a plurality of longitudinally or lengthwise spaced apart bolts, machine screws, or rivets (not shown) through the flanges 24. Such securing means would be aligned for example with the indicated lines Y shown in FIG. 4.

A flange can be welded to each end of the pipe, as is well known in the pipeline art, to create a means for connecting lengths of pipe end to end in a conventional fashion, so as achieve a pipeline of any desired length.

Claims

1. A method of forming a length of undulating pipe having a centerline and a lengthwise extending generally helical configuration symmetrically formed about said centerline, comprising the steps of: providing hot stamping apparatus consisting of a plurality of stamping stations, each station including a stationary female die half and a movable male die half, each die half having a configuration for progressively forming lengthwise extending half sections of the finished pipe;heating a sheet of material from which said pipe is to be formed;feeding said heated sheet of material into said apparatus from station to station to progressively form said helical configuration until the desired helical configuration in the lengthwise extending half section of pipe is achieved at a final stamping station;repeating said heating and feeding steps in order to create a plurality of identical lengthwise extending half sections of pipe, each said half section having a pair of lengthwise extending edges; andabutting one of said half sections of pipe to another half section of pipe along the respective lengthwise extending edges and securing such half sections along said edges thereof to create said length of undulating pipe.

2. The method of claim 1 wherein said sheet of material is a sheet of steel.

3. The method of claim 2 wherein each said half section of pipe is formed with an outwardly extending flange along each such lengthwise extending edge and said securing step includes the step of welding adjacent and abutting flanges together.

4. The method of claim 1 wherein each said half section of pipe is formed with an outwardly extending flange along each such lengthwise extending edge and said securing step includes the step of clamping adjacent and abutting flanges together by a plurality of fasteners spaced apart along such flanges.

5. The method of claim 4 wherein said fasteners are selected from the group of fasteners consisting of rivets, machine screws, and bolts and nuts.

6. The method of claim 5 including the step of positioning a sealing gasket between adjacent flanges prior to said securing step.

7. The method of claim 1 including the step of forming a radially extending flange at each end of a finished pipe for fastening one length of finished pipe in end-to-end fashion with another length of finished pipe.

8. Apparatus for forming a length of undulating pipe having a centerline and a lengthwise extending generally helical configuration symmetrically formed about said centerline, comprising: furnace means for heating sheets of material from which said pipe is to be formed;a plurality of stamping stations, each station including a stationary female die half and a movable male die half, each die half having a configuration for progressively forming lengthwise extending half sections of the finished pipe;means for feeding a heated sheet of material from said furnace means to a first stamping station and then to successive stamping stations until at a final such station the lengthwise extending half section of the finished pipe having the desired configuration is formed; andmeans for bringing one lengthwise extending half section of the finished pipe into abutting contact with another lengthwise extending half section of the finished pipe along respective lengthwise extending edges thereof for securing the half sections together along the edges thereof to create the finished pipe.