Method of producing helically corrugated metal pipe and related pipe construction
A pipe manufacturing device and method provides for pipe diameter monitoring and responsive pipe diameter control. Various pipe configurations and pipe assemblies adapted for ease of in the field connection are also provided.
This application relates generally to helically corrugated metal pipe commonly used in drainage applications and, more specifically, to a method of producing such pipe with improved diameter control and/or end connection features.
BACKGROUNDThe standard production process for producing helically corrugated metal pipe is well known and involves first forming lengthwise corrugations in an elongated strip of sheet metal, with the corrugations extending along the length of the strip. The corrugated strip is then spiraled into a helical form so that opposite edges of the corrugated strip come together and can be either crimped or welded to form a helical lock along the pipe. Diameter control of the resulting pipe is regularly an issue in the manufacturing process and is important to the functionality of the pipe from an installation standpoint when pipes are being connected end to end at a job site in the field. Attempts to address diameter control have been made in the past. U.S. Pat. Nos. 3,940,962, 3,417,587, 4,287,739 and 4,438,643 describe pipe manufacturing techniques and related equipment. Improvements are continually sought.
Joining lengths of helically corrugated metal pipe creates issues in the field. U.S. Pat. No. 5,842,727 teaches a coupling member that can be used to join the ends of two pipes in a sealed manner. Improvements in the area of pipe coupling would be advantageous as the same could reduce pipe installation costs.
SUMMARYA system and method for pipe size or diameter control in connection with the production if helically corrugated pipe is provided. Advantageous pipe configurations may be achieved. Pipe size monitoring and control may be automated.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to
The rollers of the illustrated corrugators 22 are driven by an electric motor 26 with its output linked to a gearbox/transmission arrangement 28. A forming head 30 is positioned to receive the corrugated metal strip 24 and includes a lockseam mechanism 32 located at a pipe exit side 34 of the forming head. The forming head 30 may be a well known three-roll forming head configured to spiral the corrugated metal strip 24. The lockseam mechanism 32 locks adjacent edges of the spiraled corrugated metal strip in a crimped manner to produce a helical lockseam 100 in the resulting pipe 102. Specifically, as the corrugated metal strip is helically curved back upon itself to form the pipe-shape, the locking lips 13 and 15 come together before passing into the lockseam mechanism 32, and the lockseam mechanism 32 presses the lips together to produce a lockseam that may, in one example, have the general appearance of that shown in the cross-section of
Referring back to
The pipe manufacturing device 10 also includes a pipe size monitoring device 40 along the pipe exit path, in this case shown downstream of the saw unit 36. However, the pipe size monitoring device 40 could also be located upstream of the saw unit 36. While helically corrugated pipe is generally specified, along with other parameters, by length and diameter, the term “diameter” can be difficult to apply to the pipe with absolute technical accuracy because the pipe may actually be slightly out of round. The term “pipe size” is used herein to broadly refer to any of a perimeter (inner or outer) dimension of the of the pipe, a diameter dimension of the pipe, or some other dimension of the pipe that is reflective of the flow capacity of the pipe, but the term “pipe size” specifically does not include pipe length. As used herein the term “diameter” applies even to pipe that may be out of round, in which case the diameter may be an average radial dimension measured from a generally centrally located axis of the pipe.
The pipe size monitoring device 40 can be used to provide automated pipe size control for pipe 102 as it is produced. Specifically, the device 10 may include an internal pressure roller 50 located downstream (
Referring now to
In one embodiment the control unit 10 is configured to provide pipe size control of at least two types. Specifically, in a first mode the control unit 44 effects operation of the automated drive 54 so as to maintain a substantially constant pipe size during pipe production (e.g, by comparing a measured pipe size to a desired pipe diameter stored in memory of the control unit and effecting operation of the drive 54 when the measured pipe size moves outside of a certain range about the desired pipe size, or by comparing a monitored pipe size variation to a permissible variation stored in memory and effecting operation of the drive 54 when the monitored pipe size variation exceeds the permissible variation). In a second mode the control unit 44 effects operation of the automated drive 54 so as to intentionally vary pipe size during pipe production (e.g., by comparing the measured pipe size to a desired diameter as indicated by a desired pipe diameter profile stored in memory, or by comparing monitored pipe size variation to a desired variation profiled stored in memory). Selection of either the first mode or the second mode may be made via a user interface associated with the control unit 44. In one embodiment the user interface may take the form of a touch screen display 46 that displays visual interface keys that an operator can touch and trigger. However, the user interface could also take other forms, such as a standard display in combination with a keypad. In either case, during pipe production the display may 46 provide a continuously updated visual display of measured pipe size or diameter and/or of variance of pipe size or effective diameter from a desired pipe size.
In one example of the above-mentioned second mode, pipe production is controlled so that a resulting pipe has one end with a larger diameter than its opposite end. Referring to
The pipe, with ends of different diameters, can then be worked further to produce a pipe configuration with advantageous bell and spigot connecting ends. Specifically, the larger diameter end of the pipe may be worked so as to produce a substantially corrugation free bell end 120 and the downstream end is worked to produce a spigot end 122, as shown in
In one example, an axial length of cylindrical portion 126 is at least about four inches, while in another example an axial length of portion 126 is at least about six inches. Variations are possible.
The working of the end of the pipe to form the spigot end may be achieved using a suitably formed recorrugator, which is a device known in the art. Likewise, the working of the end of the pipe to form the bell end may start by using a recorrugator to form annular corrugations at the pipe end. The resulting annular corrugations at the very end of the pipe are then eliminated to form cylindrical portion 126 by a similar rerolling process. Alternatively, one or more annular corrugations may be formed in position slightly spaced apart from the end of the pipe and the remaining helical corrugations at the end of the pipe may be eliminated by rerolling to form cylindrical portion 126.
The device 10 can be used in a process to form multiple helically corrugated metal pipe segments of similar length that are readily connectable end to end. Specifically, the method involves: (a) drawing a metal sheet off of a coil; (b) corrugating the metal sheet to produce a corrugated metal strip; spiraling the corrugated metal strip and locking adjacent edges of the spiraled corrugated metal strip in a crimped manner to produce a helical lockseam; (d) automatically monitoring pipe size of pipe being produced; (e) based upon the pipe size monitoring, automatically varying helix angle of the pipe as it is produced in a manner to intentionally vary pipe diameter; (f) producing multiple pipe segments by cutting the helically corrugated metal pipe each time a specified length of pipe is produced; (g) coordinating the pipe diameter variations of step (e) with the cutting operations of step (f) such that pipe segments are produced in the following sequence in a repeating manner: (1) producing a pipe segment having a downstream end and an upstream end, a diameter of the upstream end larger than a diameter of the downstream end, then (2) producing a pipe segment having a downstream end and an upstream end, a diameter of the upstream end smaller than a diameter of the downstream end. As a general rule the diameter of the upstream end of each pipe segment of (g)(1) will be substantially the same as the diameter of the downstream end of each pipe segment of (g)(2). For each pipe segment of (g)(1), the upstream end is rerolled or otherwise worked to produce a substantially corrugation free bell end, and the downstream end is rerolled or otherwise worked to produce a spigot end with at least one annular corrugation. For each pipe segment of (g)(2), the downstream end is rerolled or otherwise worked to produce a substantially corrugation free bell end, and the upstream end is rerolled or otherwise worked to produce a spigot end with at least one annular corrugation.
The diameter control from end to end of each pipe segment may be in accordance with a diameter profile stored in memory of the control unit. Two exemplary diameter profiles are shown in
Referring now to
Referring now to
It is recognized that the position of the pressure roller 50 could also be controlled by operator (e.g., by pushing an up or down button or by rotating a knob) in response to an indication on the operator display indicating that pipe diameter is moving or has moved out of tolerance.
Referring now to
The opposite end of the pipe 400 may be configured to be a spigot end as generally shown in
It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible. Accordingly, other embodiments are contemplated.
Claims
1-11. (canceled)
12. A method of manufacturing helically corrugated metal pipe, comprising the steps of:
- (a) drawing a metal sheet off of a coil;
- (b) corrugating the metal sheet to produce a corrugated metal strip;
- (c) spiraling the corrugated metal strip and joining adjacent edges of the spiraled corrugated metal strip in a crimped manner to produce a helical seam;
- (d) automatically monitoring diameter variations of pipe being produced;
- (e) based upon the diameter monitoring, automatically varying pipe diameter in a manner to produce a pipe segment having a first end with a diameter that is larger than a diameter of a second end;
- (f) working the first end to produce a substantially corrugation free bell end, and working the second end to produce a spigot end with an annular gasket seat.
13. The method of claim 12 wherein step (e) involves varying helix angle of the pipe segment along a length of the pipe.
14. The method of claim 12 wherein the bell end is produced with a entry lip that angles outward.
15. The method of claim 12 wherein step (f) includes forming one or more annular corrugations adjacent the substantially corrugation free bell end.
16. A method of manufacturing helically corrugated metal pipe, comprising the steps of:
- (a) drawing a metal sheet off of a coil;
- (b) corrugating the metal sheet to produce a corrugated metal strip;
- (c) spiraling the corrugated metal strip and joining adjacent edges of the spiraled corrugated metal strip to produce a helical seam;
- (d) automatically monitoring diameter of pipe being produced;
- (e) based upon the diameter monitoring, automatically varying pipe diameter;
- (f) producing multiple pipe segments by cutting the helically corrugated metal pipe each time a specified length of pipe is produced;
- (g) coordinating the pipe diameter variations of step (e) with the cutting operations of step (f) such that pipe segments are produced in the following sequence in a repeating manner: (1) producing a pipe segment having a downstream end and an upstream end, a diameter of the upstream end larger than a diameter of the downstream end, then (2) producing a pipe segment having a downstream end and an upstream end, a diameter of the upstream end smaller than a diameter of the downstream end.
17. The method of claim 16 wherein the diameter of the upstream end of each pipe segment of (g)(1) is substantially the same as the diameter of the downstream end of each pipe segment of (g)(2).
18. The method of claim 16 wherein, for each pipe segment of (g)(1), the upstream end is worked to produce a substantially corrugation free bell end, and the downstream end is worked to produce a spigot end with at least one annular corrugation.
19. The method of claim 16 wherein, for each pipe segment of (g)(2), the downstream end is worked to produce a substantially corrugation free bell end, and the upstream end is worked to produce a spigot end with annular corrugations.
20-36. (canceled)
37. A helically corrugated metal pipe assembly adapted for facilitating end-to-end connection in the field, comprising:
- a tubular structure in the form of a spiraled corrugated metal strip with opposite side edges adjacent each other and joined together to form a helical seam along a length of the tubular structure, a central region of the tubular structure helically corrugated, a first end of the tubular structure worked to provide an annular structure, a bell fitting positioned on the first end of the tubular structure and having an end portion, shrink wrap material wrapped about the pipe assembly in a region to cover the annular structure and the end portion of the bell fitting, the shrink wrap heated to form fit to the pipe assembly thereby securing the bell fitting on the end of the tubular structure and providing a sealing function between the tubular structure and the bell fitting.
38. The helically corrugated metal pipe assembly of claim 37 wherein the annular structure is an annular gasket seat with an annular gasket therein, wherein the end portion of the bell fitting engages the annular gasket.
39. The helically corrugated metal pipe assembly of claim 37 wherein a second end of the tubular structure includes an annular gasket seat.
Type: Application
Filed: Apr 21, 2006
Publication Date: Oct 25, 2007
Inventors: William Zepp (Lebanon, OH), James Schluter (Franklin, OH)
Application Number: 11/408,298
International Classification: B21C 37/12 (20060101);