Inflatable closing plug for pipes

Abstract

An apparatus for forming an inflatable closing plug has a winding head rotatable around a path defining a winding plane. The winding head is arranged to dispense one or more continuous lines from a supply of line via a guide arrangement. A preform is rotationally supported on an axis at a shallow angle with respect to the winding plane such than the winding plane intersects the preform. By providing a spreading arrangement to locate the windings on the preform over a band having a width perpendicular to the winding plane, a smoother distribution of windings can be achieved.

Claims

1. A method of manufacturing an inflatable plug, comprising: (a) providing a preform defining a preform axis having a first pole and a second pole, wherein the first pole is closed by a closure having a diameter d; determining the length of the diameter d and d/2 of the closure; determining the center of the diameter of the closure; placing a wind A onto the perform such that it passes the first pole at a distance Ra, wherein Ra is a distance from center of the diameter of the closure to the wind A; placing a wind B onto the perform such that it passes the first pole at a distance Rb, wherein Rb is a distance from center of the diameter of the closure to the wind B; placing a wind C onto the perform such that it passes the first pole at a distance Rc; wherein Rc is tangential to the closure, which corresponds to about the diameter d/2 of the closure; thereby forming a band consisting of the winds A, B, and C; wherein the preform does not rotate during formation of the band; wherein the winding plane intersects the preform axis and passes adjacent to one pole; wherein at least one of a winding head and the preform is at least laterally displaced at a predetermined distance along an axis generally perpendicular to the winding plane during winding; (b) rotating the preform a predetermined angular rotation after each band is formed; (c) repeating steps (a) and (b) as necessary to obtain a required number of windings, wherein by repeating step (b) a further band is formed that overlaps a previous band; and (d) securing the line in an elastic matrix to form a peripheral wall.

2. The method according to claim 1, further comprising: attaching a media inflow conduit to the peripheral wall at one of the poles, the media inflow conduit comprising a mechanical connector for releasably connecting to a media source.

3. The method according to claim 1, further comprising: attaching a media inflow conduit to the peripheral wall at one of the poles, the media inflow conduit comprising a mechanical connector for releasably connecting to a media source.

4. The method according to claim 3 wherein the media inflow conduit is a high pressure hose capable of withstanding internal pressures greater than 1.5 bar.

5. The method according to claim 3 wherein the media inflow conduit is a high pressure hose capable of withstanding internal pressures greater than 5 bar.

6. The method according to claim 3 wherein the media inflow conduit is a high pressure hose capable of withstanding internal pressures greater than 16 bar.

7. The method according to claim 1, wherein each winding in each band is at a different distance from the pole.

8. The method according to claim 1, wherein the windings A, B, and C cross each other at around the mid-point or equator of the perform.

9. The method according to claim 1, wherein the wind A is placed first onto the perform followed by the wind B and finally by the wind C to form the band and wherein the distance Ra is larger the distance Rb and the distance Rb is larger than the distance Rc.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The features and advantages of the invention will be appreciated upon reference to the following drawings, in which:

(2) FIG. 1 is a schematic perspective view of a first embodiment of an apparatus for forming an inflatable closure plug;

(3) FIGS. 2A and 2B are end views of a balloon wound with the apparatus of FIG. 1;

(4) FIG. 3 is an end view of a balloon wound in an alternative manner using the apparatus of FIG. 1;

(5) FIG. 4 is a schematic perspective view of an alternative version of the apparatus of FIG. 1;

(6) FIG. 5 is a top view of a balloon being wound by the apparatus of FIG. 4;

(7) FIG. 6 is a schematic perspective view of a second alternative version of the apparatus of FIG. 1;

(8) FIG. 7 is a perspective view of a first embodiment of a spreading edge according to the invention;

(9) FIG. 8 is a perspective view of a second embodiment of a spreading edge according to the invention;

(10) FIG. 9 is a schematic perspective view of a second embodiment of an apparatus for forming an inflatable closure plug according to the invention;

(11) FIG. 10 is a partial view of the guiding arm of FIG. 9;

(12) FIG. 11 is a view of the apparatus of FIG. 9 during winding of a plug;

(13) FIG. 12 is a view showing insertion of an inflatable plug into a pipe to be closed;

(14) FIG. 13 is a view showing an inserted inflatable plug in deflated state; and

(15) FIG. 14 is a view showing of the plug of FIGS. 12 and 13 in an inflated state.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(16) Designated with the numeral 1 in FIG. 1 is an apparatus for forming an inflatable closure plug according to a first embodiment of the invention. According to the figure there is shown a balloon-like element 3 which serves as a preform on which to wind a closing plug. The balloon 3 has a first pole N closed by closure 2 and is connected at its other pole S to a shaft 4. The shaft 4 serves as an inlet conduit into an interior space within the balloon 3 and is provided with a closing valve 6 which can be placed in an open or closed position. In the situation of FIG. 1, the balloon 3 is partially inflated to its nominal working diameter and the valve 6 is closed. In this state the balloon 3 is generally elongate and round in cross-section.

(17) The shaft 4 can extend wholly through the balloon-like element 1 into the narrowed end portion 2 of the element, although this is not strictly necessary. The shaft 4 is inserted into a rotatably mounted carrier 8 which can be rotated in continuous or stepwise manner in the direction of the arrow P1 by a motor 9 about preform axis A-A. The motor 9 may also rotate in the reverse direction counter to P1.

(18) A moveable guide arm 12 is arranged to rotate around a winding axis B-B. The arm 12 has a guide eye 13 which during rotation follows a path designated with the arrow P2 defining a winding plane W. The centre of this path coincides with a point of intersection of the winding axis B-B and the preform axis A-A. The axes A-A and B-B are positioned with respect to one another such that the winding plane W passes through the balloon 3 and is angled at a small angle to the preform axis A-A. As a consequence, the eye 13 will pass close to but not over the pole S on the rear side of the balloon 3 and it will pass the pole N at the front side of the balloon.

(19) The arm 12 is mounted on a winder shaft 10 and is driven to rotate by a winder motor 11. A line 7 can be unwound from a spool 5 and is guided through the winder shaft 10 and an interior passage in arm 12, to the eye 13. The line is formed of Dynema fibre of 165 dTex grade. Winder motor 11 is mounted on a bed 14 to shuttle backwards and forwards along the winding axis B-B. Movement of the winder motor 11 along the bed 14 may be by any conventional means such as a solenoid, linear motor, endless screw or the like. Control of the motor 9, winder motor 11 and bed 14 is provided by a controller 20. A latex spray device 15 is also located adjacent to the balloon for operation as described below.

(20) In use, an end of the line 7 is fixed in relation to the periphery of the balloon 3. The winder motor 11 is operated to rotate the arm 12 causing the guide eye 13 to transcribe a path around the winding plane W. As the arm 12 moves, line 7 is withdrawn from eye 13 by the tension caused by the fixing of the line 7 on the balloon. By ensuring that the passage through the winder shaft 10 and guide arm 12 is unrestricted, the tension required to withdraw line 7 from spool 5 may be relatively low. As a result, the line 7 may be applied as a relatively loose winding 16A to the balloon 3. As the arm 12 rotates around the balloon 3, the winder motor 11 also retracts on bed 14. This causes successive windings 16B, 16C to be applied parallel to winding 16A as a band 18.

(21) After three rotations of arm 12, the winder motor 11 has fully retracted on bed 14. The motor 9 then acts to rotate the balloon 3 one step forwards around the preform axis A-A corresponding to an angular rotation of 11 degrees. At the same time, spray device 15 is actuated to spray a light coating of latex onto the surface of the balloon 3. The arm 12 continues to rotate in order to apply three further windings as the winder motor 11 slides forwards on bed 14. After 17 steps of the motor 9, the balloon will have rotated half a turn and will be completely covered with windings 16 and latex. Operation continues for a number of further revolutions until the total number of windings corresponds to that required to achieve the desired pressure rating for the plug.

(22) After winding is completed, the shaft 4 is removed from sleeve 7 and the balloon 3 is allowed to dry in order to cure the latex. Thereafter appropriate fittings for the intended use are applied e.g. a high pressure media inlet hose.

(23) FIG. 2A illustrates an end view onto pole N of the balloon 3 taken along axis A-A. As can be seen, closure 2 has a diameter d. Balloon has a nominal working diameter D at which winding takes place. First winding 16A is placed onto the balloon 3 such that it passes the pole at a distance Ra. Winding 16B is placed at a distance from the pole of Rb. Winding 16C is placed such that it is tangential to the closure 2 at distance Rc corresponding to d/2. The three windings 16A, B, C thus form a band having a width b of Ra-Rc. As it will be understood, the width b corresponds to the distance moved by the winder motor 11 as it reciprocates on bed 14.

(24) FIG. 2B is a view corresponding to FIG. 2A after the motor 9 has incremented forwards 4 steps and after a further 12 windings have been applied to the balloon 3.

(25) In the embodiment of FIGS. 1 and 2, the winder motor 11 reciprocates on bed 14 at a given angular position of the motor 9 and shaft 4. In an alternative mode of operation depicted in FIG. 3, the motor 9 is controlled to rotate the shaft 4 a step at a time without movement of the winder motor 11 on bed 14. For the sake of simplicity, in FIG. 3 the situation is shown in which each step is of 90 and a single winding 16 is placed at each step. It will however be understood that in reality many smaller steps may be taken and more windings may be placed on each layer. Initially a first series of four windings 16A is placed at a distance Ra from the pole N to form a first winding layer on the balloon surface. Thereafter the winder motor 11 is displaced and during a second rotation of the shaft 4, a second series of windings 16B are placed at a distance Rb from the pole in a second layer lying over the first layer. During a third rotation, a further series of windings is placed at distance Rc to form a further layer. Although the windings 16 are placed in a different sequence, they still form a band 18 and have the effect of reducing the overall thickness of the region around the pole by a factor of three compared with a similar number of windings all located at distance Ra.

(26) The skilled person will understand that many alternative ways of controlling deposition of the windings may be contemplated that still achieve the same effect of reduced winding overlap around the poles N, S. Furthermore, although the movement of the winder motor 11 to three different positions has been described, the skilled person will understand that it may be moved to any number of intermediate positions. It will also be understood that the winder motor 11 can reciprocate even while the arm 12 and the motor 9 rotate.

(27) According to FIG. 4, there is shown a variation of apparatus 1 according to an alternative embodiment of the invention. The apparatus of FIG. 4 differs from that of FIG. 1 only in that the winder motor 11 is mounted to pivot on bed 14 rather than reciprocate. As a result of such pivoting, the angle between the winding plane W and the preform axis A-A can be increased and decreased.

(28) FIG. 5 is a view looking downward onto the balloon 3 of FIG. 4. As a result of the pivoting of winding motor 11, windings 16 A, B, C are spaced from one another close to poles N, S in a similar manner to the first embodiment. In this case however, the windings cross each other at around the mid-point or equator E of the balloon 3. In this region, the winding density is lower than at the poles and overlapping of the lines may have less influence on the wall thickness. In general the lines are more widely spaced at the equator. Furthermore, due to natural variations in balloon shape, the crossing points rarely all come to lie exactly above one another and the effect on the final product is minimal.

(29) In FIG. 6, a second variation of the apparatus 1 is shown in which a pair of diagonally opposed guide arms 12A and 12B are connected to winder shaft 10. Each arm 12A, 12B has a guide eye 13A, 13B from which lines 7A, 7B are dispensed. In the variation of FIG. 6, both guide eyes are aligned in the same winding plane W.

(30) The lines 7A, 7B are dispensed from two separate spools 5A, 5B. In order to prevent lines 7A, 7B from twisting together as the winder shaft rotates, spools 5A, 5B are mounted on a spool holder 22. Spool holder 22 and winder shaft 10 can then rotate together at the same speed, driven e.g. by a mechanical connection to the winder motor 11.

(31) In operation, each rotation of the winder motor 11 causes two windings 16 to be deposited onto the balloon 3. The winder motor 11 may therefore retract on bed 14 after each half winding while still maintaining the same coverage. As will be evident, the total number of windings deposited at a given speed of winding is doubled leading to increased efficiency of operation. In a non-shown embodiment, the guide eyes 13A, 13B may be offset from one another perpendicular to the winding plane W. A full revolution of the winder motor 11 thus leads to two full windings being deposited parallel to one another, spaced by the offset of the guide eyes. The skilled person will understand that more spools and more arms may be used to further increase the rate of winding. The arms may be equally spaced around the winder shaft 10 or may be arranged adjacent to one another. Furthermore it may be noted that a single guide arm 12 may also carry multiple separate lines 7A, 7B . . . each to an individual guide eye 13 A, B . . . .

(32) According to FIG. 7 there is shown a spreading edge 23 that may be affixed to the arm 12 of apparatus 1 to guide the line 7 on exit from the guide eye 13. The spreading edge 23 serves to spread the individual fibres of the Dynema line 7 as they are applied to the balloon 3. According to FIG. 7, the guide arm 12 is provided with a spatula attachment 24 connected to the guide eye 13. The spatula attachment 24 can be pivoted up and down with respect to arm 12 and fixed at a desired position by conventional means such as a screw or by friction. The spatula attachment 24 protrudes rearwardly according to the sense of rotation P2 to a curved spreading edge 23. Grooves 26 and upstanding borders 28 are provided leading from the eye 13 to the spreading edge 23.

(33) In use, line 7 is dispensed from eye 13 during rotation of the arm 12. The line 7 is drawn over the spatula attachment 24 and spread by grooves 26 and by the rounded spreading edge 23. The line 7 is thus dispensed as a widened band 18 onto the balloon 3. According to the angular position in which the spatula attachment 24 is fixed, it will have a greater or lesser spreading effect on the line 7. The upstanding borders 28 prevent the line 7 from dropping off the sides of the spatula attachment 24. As applied to the variation disclosed in FIG. 1, the spreading edge 23 and reciprocally mounted winder motor 11 can both work in combination to provide even distribution of line 7 over the surface of the balloon 3.

(34) An alternative spreading edge 23 is depicted in FIG. 8 in the form of a roller attachment 30 which may also be affixed to the end of the guide arm 12 in a similar manner to the spatula attachment 24 of FIG. 8. The roller attachment 30 comprises a fork 32 supporting a freely rotating roller 34. Roller 34 has a convex portion 36 and upstanding edge portions 38. The convex portion 36 is provided with herringbone grooves 40. According to FIG. 8, the roller attachment 30 is pivoted in a downwards position towards the balloon 3, whereby the line 7 runs under the roller 34. It is understood that it could also be pivoted to an upwards position as is the spatula attachment of FIG. 7.

(35) In use, the line 7 is drawn through the eye 13 and over the roller 34 causing it to rotate. As it rotates, the form of the convex portion 36 and the grooves 40 cause the line 7 to be spread outwardly into a band 18. The upstanding edge portions 38 prevent the line from slipping off the roller 34.

(36) In FIG. 9 there is shown according to a second embodiment of the invention an apparatus 100 for simultaneously winding a plurality of lines about a balloon-like element. The apparatus 100 comprises a continuous conveyer 103, attached to which are a plurality of spool seats 105. In the illustrated embodiment six spool seats are shown, but fewer or more may be provided. On each of the spool seats 105 a spool 107 of line 109 is provided.

(37) The line 109 from each spool seat 105 passes from its spool 107 to an arm 111. The arm 111 is provided at a distal end with a head 113 comprising a plurality of eyelets 115, seen in FIG. 10. Each line 109 runs through a separate eyelet 115. Guide loops 116 for the lines 109 are provided around the conveyor 103. A guide 117 is also preferably provided on the arm 111 in advance of the head 113 to keep the individual lines 109 separate, thus avoiding tangling.

(38) The arm 111 is attached to the continuous conveyer 103. As the conveyer turns, as indicated by the arrows P2 in FIG. 9, the arm 111, the spool seats 105, and the spools 107 move together along the path of the conveyer 103. The head 113 travels along a winding path 119 dictated by the conveyer 103 and defines winding plane W as shown in FIG. 11. Also shown in FIG. 9 is a support 108 which is attached to a non-rotating body 104 of the conveyor 103.

(39) Referring to FIG. 11, there is shown a partially inflated balloon-like element 121 which serves as part of a closing plug. The balloon-like element 121 is closed at its pole N by closure 123 and connected at its pole S to a shaft end part 127 that is releasably closed by a valve 129.

(40) The shaft end part 127 is releasably connected to a motor 131 for continuous or stepwise rotation of the balloon-like element 121 in the direction of the arrow P1, about the major axis A of the balloon-like element. The balloon-like element 121 is supported at its other end by closure 123 which rests on the support 108.

(41) The major axis A of the balloon-like element 121 is arranged at a predetermined angle in relation to the winding plane W and partially penetrates through the plane to rest on the support 108. The balloon-like element 121 is thus placed such that as the head 113 moves along the path 119, it passes near to the pole N on a first-side of the balloon-like element, and near to the pole S on the opposite-side of the balloon-like element. The head 113 is thus led in a winding motion about the balloon-like element passing from the pole N to the pole S on a first side of the balloon-like element and from the pole S to the pole N on the opposite side.

(42) To achieve winding of the lines 109 about the balloon-like element 121 the outer ends of the lines 109 that are passed through the eyelets 113 are fixed in relation to a surface part of the balloon-like element 121. The head 113 is moved along the winding path 119 so that the lines are pulled about the balloon-like element in a quasi-meridian fashion, at an angle to the axis A. In this manner the lines 109 are deposited as a relatively broad band 118. As a result of the elongate path taken by the conveyor 103, the tension applied to the lines during winding onto an elongate balloon-like element is more even and increased tension at the poles is avoided.

(43) The motor 131 acts to rotate the balloon either continuously at a varied or fixed rpm, or in step movements. Thereby the rotational movement of the balloon can provide meridian fashion windings of lines around the whole circumference of the balloon-like element. The rate and type of rotation determines the precise lie and spacing of each group of successive windings. It is preferred that the rotational movement is step-wise because this winds the lines closely in line with the axis A.

(44) It is also possible to adjust the spacing of the lines in each group of simultaneously wound lines by adjusting the relative spacing of the eyelets 115 in relation to the surface of the balloon-like element 121. This is conveniently achieved as shown in FIG. 10. The head 113 is joined to the arm 111 at a pivot 141. The pivot 141 allows the angle of the head to be altered, and thereby the spacing of the eyelets 115 viewed from the surface of the balloon-like element to be altered. In this manner, the band 118 can be made broader or narrower as desired.

(45) As in the previous embodiment, an adhesive such as latex can be sprayed by means of a spray device over the deposited line windings and the surface of balloon-like element 121 so that an intimate adhesion occurs between the line windings and the balloon-like element 121. Alternatively, the adhesive is brushed over the line windings and balloon surface. The adhesive can preferably be applied during the winding of the lines 109 around the balloon-like element 121, preferably with adhesive being applied after each winding.

(46) In the disclosed embodiment, the balloon-like element 121 is inflated to predetermined size by connecting the shaft end part 127 to a pressure source, opening the valve 129, inflating the balloon-like element 121 to the desired size and subsequently closing the valve 129. The balloon-like element thereby acquires some firmness during winding of the lines. The predetermined size generally represents the nominal bore size that the plug is intended to close. It will of course be understood that winding in different configurations is also possible.

(47) In FIGS. 12, 13 and 14 the manner of application of the inflatable plug 133 obtained by the procedure of FIG. 11 is further described in combination with conventional flow stop equipment. The plug 133 is connected at the pole S onto a pressure line 135 which is in communication with a pressure source via a valve 137. Initially vacuum may be applied to flatten the plug 133 as much as possible, allowing it to be wound or compressed to a small diameter. The plug 133 is then pushed into an introducer shoe 136 which is inserted into a pipe 139 for closing via a relatively small opening made through the wall. This method as shown in FIGS. 12 and 13 uses a saddle 138, which is applied to the pipe 139 avoiding cutting through an entire section of the pipe. Alternatively the introducer shoe may be inserted via an existing branch connector. In such a method it is of great advantage to have a plug that is flexible and can be tightly folded or wound to a small diameter. The smaller the size of the introducer shoe, the smaller the hole that needs to be made into the pipe 139. In order to ensure the integrity of a pipeline it is generally preferable that the bored hole is no more than of the pipe diameter. Plugs having thick walls and rough outer surfaces can often prove difficult to insert in such a method. The plug 133 according to the present invention, by virtue of its reduced thickness polar regions can be inserted into a relatively narrower shoe than previous plugs of similar working size and pressure.

(48) Once the shoe 136 is in position, the plug 133 may be advanced into the pipe 139. The plug 133 may be advanced in any convenient manner, by hand or using a rack and pinion type introducer mechanism (not shown). Because of its increased flexibility and smooth surface, the plug 133 of the present invention is also more convenient to advance through the shoe 136 and can more easily bend into alignment with the pipe 139.

(49) By opening valve 137, compressed air, or another suitable inflation media, is admitted into the plug 133, whereby it stretches in substantially radial sense. This is shown in FIG. 14. Due to the line windings, which are made of material with little extensibility, the balloon will assume a melon-shaped form, whereby the outer periphery will become larger and touch against the inner wall of the pipe 139. The axial distance between the poles N, S reduces due to the inflation as the plug 133 becomes more spherical. As the plug 133 becomes constrained by the surrounding pipe, it takes up an elongate-melon-shaped form conforming to the inner walls of the pipe 139.

(50) As a result of the restriction on the axial extension created by the reinforcement lines the balloon-like element 121itself a very elastic materialwill nestle firmly against the inner wall of pipe 139 and be able to build up pressure against the wall sufficient to resist possible pressure along the pipe. Because of the winding procedure presently described, the outer surface of the plug 133 is smoother, leading to improved pressure retention. After use, retracting the plug 133 from the pipe 139 is also facilitated for the same reasons.

(51) Further modifications in addition to those described above may be made to the structures and techniques described herein without departing from the spirit and scope of the invention. Accordingly, although specific embodiments have been described, these are examples only and are not limiting upon the scope of the invention.