GB2045116A - Coating pipes - Google Patents

Abstract

In conveying a pipe through a coating zone (6) in which it is unsupported within the zone, being supported by the conveyors outwith the coating zone, the pipes (2-5) are connected end-to-end by releasable interior couplings (1) to form a continuous line of pipes for passage through the coating zone. A releasable pipe coupling Figures 2 and 3 is provided which is detachably securable at its periphery in the bore of one pipe to provide at one end of the pipe a peripheral projection (24) which is removably insertable into the bore of a second pipe to provide a seating for the second pipe. The coupling includes arcuate flanges (27) which engage with the inner wall of the first pipe by bringing together of support arms (14, 15) upon rotation of threaded spindle (13). <IMAGE>

Description

SPECIFICATION Improvements relating to the treatment of pipes, tubes or the like This invention relates to the treatment of pipes, tubes or the like (hereinafter simply called pipes), and is particularly concerned with the feeding of a plurality of pipes lengthwise in succession through a treating zone within which no support can be provided for the pipe on account of the nature of the treatment being given to the pipe in the zone.

For example, in the coating of heated steel pipes with an epoxy resin, each pipe in succession is moved endwise through the treating zone in which a coating is applied and then left untouched by any support for a period of time to gel. Normally, feeding and withdrawing conveyors with associated hold- down rollers are provided respectively at the zone's inlet and outlet. As each conveyor and its hold-down rollers is capable of supporting only one-half of the length of the pipe in overhanging or cantilever position in the treating zone, it follows that the length of the treating zone is limited and, as the gel time remains constant, production throughput is correspondingly limited.

The object of the present invention is to provide for lengthening of the treating zone and consequent greater production throughput than hitherto.

According to the present invention a method of treating pipes comprises releasably coupling together a plurality of pipes end-to-end to form a line of pipes, passing the line through a treating zone so that coupled pipes together bridge the treating zone, and removing each treated pipe from the line.

Preferably the method includes releasably fitting a pipe-supporting device in the leading end of a pipe so that a portion of the device projects from the pipe end, feeding the fitted pipe forwards so that the projecting portion of the device engages in the rear of a pipe immediately ahead to effect releasable coupling of the pipes, and feeding a coated pipe forwards to detach same from the device fitted in the next preceding pipe of the line.

By virtue of the invention the length of the treating zone can be increased beyond one-half of the pipe length, so that the speed of passage of the line of pipes through the treating zone can be increased without adversely affecting the treatment. Thus, in treating pipes by, say, coating them with plastics, the rate of production of coated pipes can be increased without reducing the normal gel time.

Further according to the present invention we provide a pipe coupling for releasably connecting together a pair of pipes end-to-end for treatment purposes, comprising a pipe-supporting device having a pair of adjacent peripherally extending supporting means respectively insertible into the bores of first and second pipes, the first of said supporting means being adjustable radially into gripping en gagement with the first pipe to secure the device to the first pipe, and the second supporting means following said secural of the device being removably insertible into the second pipe to form a seating for the second pipe.

In one form of the aforesaid pipe coupling the first and second peripherally extending supporting means consist of a series of peripherally spaced supports, and the device includes a central axially extending rod, a pair of axially spaced hubs mounted on the rod for axial adjustment relatively to each other, and a pair of opposed outwardly convering sets of peripherally spaced radial arms whereof the sets of inner ends are pivotally connected to the respective hubs and the sets of outer ends are pivotally connected to the supports so that axial adjustment of the hubs effects radial adjustment of the supports.

In another form of the aforesaid pipe coupling the first and second peripherally extending supporting means include first and second coaxial tube formations, and the first supporting means include also a peripheral series of screw jacks mounted on the first tube formation within same and in registry with a corresponding peripheral series of openings therein so that the jacks are radially adjustable into gripping engagement with the first pipe.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure lisa diagrammatic view showing the feeding of a line of pipes through a coating machine.

Figure 2 is an end elevation of one form of pipe coupling for use in forming the pipe line of Figure 1.

Figure 3 is a fragmentary side view of the coupling of Figure 1.

Figure 4 is an enlarged sectional side view of part of Figure 3.

Figure 5 is a fragmentary sectional side view showing a modification of Figure 4.

Figure 6 is an end elevation of another form of pipe coupling.

Figure 7 is a sectional side view on the line Vil-VII of Figure 6.

Figures 8 and 9 are respectively side and end views of a detail of Figure 7.

Figure 10 is a fragmentary sectional side view showing a modification of Figure 7.

Figure 11 is a fragmentary end view in the direction of arrow Xl in Figure 10.

Referring to Figure 1, pipe couplings as at 1 are used to couple together a plurality of pipes 2, 3, 4 and 5 to form a line of pipes to be coated. The coating application area is indicated at 6, and feeding and withdrawing conveyors 7 and 8 move the line of interconnected pipes in the direction indicated by the arrows. A hold-down roller 9 is provided at the inlet end of the area 6. As indicated at 10, the unsupported length of pipe line in the coating application area 6 is in excess of half the length of a pipe. In use of the pipe couplings, a coupling 1 is inserted into the leading end of the pipe 5 before the pipe is placed on the feeding conveyor 7.The feeding conveyor 7 carrying the pipe 5 to be coated is accelerated to cause the axially projecting portion of the coupling 1 on the pipe 5 at the front to enter the bore at the rear of the pipe 4 immediately ahead, and thereby effect coupling of the pipes 4 and 5, white the withdrawing conveyor 8 carrying a coated pipe 2 is accelerated to draw the rear of the coated pipe 2 clear of the axially projecting portion of the coupling 1 on the pipe 3 immediately to the rear and thereby effect uncoupling of the coated pipe 2 which is then lifted from the conveyor 8. The coupling 1 is removed from the succeeding pipe 3 and is returned for re-use.

Referring to Figures 2 to 4, a pipe coupling suitable for use in the foregoing method consists of a pair of hubs 11 and 12 axially spaced on a rod 13, a pair of opposed sets of three equispaced radial arms 14 and 15, the sets being pivotally connected at their inner ends 16 and 17 to the respective hubs 11 and 12 and converging outwardly, and a set of three peripherally equispaced supports 18 pivotally connected at 19 and 20 to the outer ends of the sets of arms 14 and 15. The hub 11 is in the form of a sleeve and is freely slidable on the rod 13 and engaged externally by a collar 21 fixed to the rod 13, a thrust washer 22 being provided between the collar 21 and the sleeve 11.

The hub 12 is a threaded sleeve engaging a threaded end portion of the rod 13. The inner ends of the arms 14 and 15 are forked to engage over radial flanges on the collar and sleeve, and are connected to the flanges by pivot pins 16 and 17. The rod 13 has a squared end 23 to enable turning of the rod by a key to effect radial adjustment of the supports 18. Each support 18 consists of a lead shoe 24 and a lagging shoe 25, each shoe being of angle section and of arcuate shape. The arcuate peripheral flanges 26 and 27 of the shoes are lined with friction material as shown and engage the bore walls of the respective pipes, while the radial flanges 28 and 29 of the shoes define between them a radial slot 3Q. The peripheral flange 26 of each lead shoe includes a frusto-conical leading end portion 31 for guiding the shoe to pipe-supporting position in the pipe.The outer ends of the arms 14 and 15 are forked to engage over central radial webs 32 and 33 within the angles of the shoes, and are connected to the webs by pivot pins 19 and 20. A T-section annular protective member 34 has its radial flange 35 engaged in the radial slots 30 between the shoes, and has its lateral flanges 36 and 37 enclosing the bevelled marginal portions of the pipes to be coupled so as to mask said portions during the pipe-coating operation. The flange 35 and the flanges 28 and 29 of the shoes are secured together by bolts (not shown).

Advantages of this coupling are: (a) High strengthlweight ratio of the attachment.

(b) Automatically self-centering and equal force on each arm.

(c) Provision for bevel protector and cut back mask.

(d) Limited area of contact with the pipes means low thermal conductivity.

(e) Can electrically ground the pipes during the treatment.

(f) Ease of handling.

(g) Tolerates limited ovality.

(h) Tolerates wall thickness variations.

(i) Easily adapted for different pipe diameters.

(j) Can be used in any longitudinal pipe conveying process.

Referring to Figure 5, the leading shoe of each support 18 of the coupling is replaced by an axially extending roller 38 having a cylindrical peripheral portion 39 providing a seatforthe pipe and having a frusto-conical peripheral portion 40 to facilitate entry of the roller into the pipe. The roller 38 is rotatably mounted on a bracket 41 whereof an end wall 42 is secured to the flange 29 of the lagging shoe 25 by a bolt 43 which serves as a spindle for the roller. The peripheral series of supporting rollers of this modification is useful when the production process requires rotation of the pipes during surface treatment, e.g. the protective coating of the pipes.

Referring to Figures 6 to 9, the supports consist of a pair of co-axial end-to-end rolled steel pipe sections 44 and 45 having at their adjacent ends annular flanges 46 and 47 engaging the radial flange of the cover 34 and secured together by a peripheral series of bolts 48. The pipe sections have outwardly convergent frusto-conical end walls 49 and 50 which facilitate insertion of the coupling into the respective pipe ends 51 and 52. Within the pipe section 44 and adjacent to the flanged end thereof is a diametrically extending strengthening tube 53 secured at its ends to the wall of the section.Also within the pipe section 44 are mounted a peripherally spaced series of screw jacks 54 each consisting of a bracket 55 secured to the section wall, a threaded bolt 56 carried by the bracket, and a clamping head 57 connected to the end of the bolt and having an arcuate face 58 conforming to the curvature of the bore of the pipe 51. A peripheral series of openings 59 in the pipe section 44 permit passage of the heads 57 through the pipe section into engagement with the production pipe 51.

By tightening the bolts 56, the heads 57 are expanded radially into clamping engagement with the pipe 51.

To facilitate handling of the coupling, the pipe section 44 has therein a peripheral series of axial slots 60, and a handle 61 is provided on the tube 53.

With this arrangement the coupling is automatically centred, and the screw jacks are then tensioned to a nominal stress. The outer diameter of the coupling pipe section is designed to fit the heaviest pipe wall thickness for a specified diameter. To achieve en gagement for a production pipe of similar outer diameter but lighter wall thickness, an outer sleeve of thin pipe of the required wall thickness to compensate for the circumferial gap is slipped over the coupling pipe section so that the required tensile engagement stress can be achieved.

Referring to Figures 10 and 11, the pipe section 45 of Figure 7 is replaced by a peripheral series of axially extending rollers 60 each having a cylindrical inner end portion 61 and frusto-conical outer end portion 62 and each being rotatable on a spindle 63 carried by a bracket 64. A pair of webs 65 and 66 connect the bracket 64 to the pipe section 44 interiorly thereof. The series of rollers 69 facilitate the rotation of the supported production pipes when their surface treatment necessitates their rotation.

Claims (16)

1. A method of treating pipes comprising releasably coupling together a plurality of pipes end-to end to form a line of pipes, passing the line of pipes through a treating zone so that coupled pipes together bridge the treating zone, and removing each treated pipe from the line.

2. A method according to claim 1, including releasably fitting a pipe-supporting device in the leading end of a pipe so that a portion of the device projects from the pipe end, feeding the fitted pipe forwards so that the projecting portion of the device engages in the rear of a pipe immediately ahead to effect releasable coupling of the pipes, and feeding a coated pipe forwards to detach same from the device fitted in the next preceding pipe of the line.

3. A method of treating pipes, substantially as hereinbefore described.

4. A pipe coupling for releasably connecting together a pair of pipes end-to-end for treatment purposes, comprising a pipe-supporting device having a pair of adjacent peripherally extending supporting means respectively insertible into the bores of first and second pipes, the first of said supporting means being adjustable radially into gripping engagementwith the first pipe to secure the device to the first pipe, and the second supporting means following said secural of the device being removably insertible into the second pipe to form a seating for the second pipe.

5. A pipe coupling according to claim 4, wherein a ring of T-section is disposed between the pair of adjacent supporting means so as to mask the adjacent end portions of the pipes against treatment.

6. A pipe coupling according to claim 4 or 5, wherein the first and second peripherally extending supporting means consist of a series of peripherally spaced supports, and the device includes a central axially extending rod, a pair of axially spaced hubs mounted on the rod for axial adjustment relatively to each other, and a pair of opposed outwardly converging sets of peripherally spaced radial arms whereof the sets of inner ends are pivotally connected to the respective hubs and the sets of outer ends are pivotally connected to the supports so that axial adjustment of the hubs effects radial adjustment of the supports.

7. A pipe coupling according to claim 6, wherein each support includes a pair of adjacent shoes presenting arcuate faces for engagement respectively with the first and second pipes.

8. A pipe coupling according to claim 7, wherein the arcuate faces of the shoes are faces of layers of friction material.

9. A pipe coupling according to claim 6, wherein each support includes a shoe presenting an arcuate face for engagement with the first pipe and an axially extending roller presenting a cylindrical face for engagement with the second pipe.

10. A pipe coupling according to any one of claims 7 to 9, wherein the faces of the supports for engagement with the second pipe have cylindrical inner end portions and frusto-conical outer end portions engageable with the pipe to facilitate entry of the supports to positions in which the pipe seats on said inner end portions.

11. A pipe coupling according to claim 4 or 5, wherein the first and second peripherally extending supporting means includes first and second coaxial tube formations, and the first supporting means include also a peripheral series of screw jacks mounted on the first tube formation within same and in registry with a corresponding peripheral series of openings therein so that the jacks are radially adjustable into gripping engagement with the first pipe.

12. A pipe coupling according to claim 11, wherein each tube formation has a cylindrical inner portion to provide a seat for the pipe and a frusto-conical outer portion to facilitate insertion of the tube formation into the pipe.

13. A pipe coupling according to claim 4 or 5, wherein the first peripherally extending supporting means include a tube formation and a peripheral series of screw jacks mounted on the tube formation within same and in registry with a corresponding peripheral series of openings therein so that the jacks are radially adjustable into gripping engagement with the first pipe, and the second peripherally extending supporting means include a series of peripherally spaced axially extending rollers.

14. A pipe coupling according to claim 13, wherein the peripheral faces of the tube formation and of the rollers have frusto-conical outer end portions to facilitate insertion of the tube formation and the rollers into the respective pipes.

15. A pipe coupling according to claim 13 or 14, wherein the first peripherally extending supporting means include diametrical tubing secured within the tube formation to strengthen same, and the axially extending rollers are mounted on said tube formation.

16. Pipe-couplings substantially as hereinbefore described with reference to the various Figures of the accompanying drawings.