GB2369172A

GB2369172A - Apparatus for reinstating drains or underground passages

Info

Publication number: GB2369172A
Application number: GB0202419A
Authority: GB
Inventors: Kenneth Latimer Scott; Robert Mills
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-05-17
Filing date: 2000-05-17
Publication date: 2002-05-22
Anticipated expiration: 2020-05-17
Also published as: GB0202419D0; GB0202418D0; GB2369172B; GB2369171A

Abstract

Apparatus for reinstating damaged drains or underground passages, especially, but not exclusively, drains of the so-called pitch-fibre type, by introducing a cable through the drain or passage between adjacent access chambers, drawing a cutter or former implement through the drain or passage to cut through material obstructing the drain or passage or to push it back to shape, removing any debris produced thereby, introducing a flexible liner into the section of the drain or passage between the said two access chambers and inflating the flexible liner to bring it substantially into contact with the walls of the drain or passage, and causing the liner to cure or set to a substantially rigid form. The apparatus also includes a drum 14 carried on a support which also carries cable guide means 28 which are adjustable in height to line up with drains at different depths.

Description

2369 1 72

APPARATUS FOR REINSTATING DRAINS OR UNDERGROUND

PASSAGES

The present invention relates generally to a method and apparatus for reinstating 5 drains or underground passages, and particularly (although not exclusively) to the reinstatement of drains of the so-called pitch fibre type.

Pitch fibre drains were installed extensively in commercial and domestic building work for a number of years and there are a considerable number of such drains in 10 use at present. These drains, however, have a limited working life and after a period of time the lining material fails, allowing the wall of the drain to collapse and restrict flow through the drain. In severe cases this blocks the drain entirely.

Conventional procedures for reinstating such failed drains require excavation along 15 the line of the drain and reinstatement of fresh liners with suitable properties.

Where such drains have been laid under buildings this is, plainly, an extremely troublesome operation. In exposed locations the cost of reinstating such drains is extremely high. The present invention seeks to provide a method and apparatus by which collapsed drains or other underground passages may be reinstated to allow 2 o free flow of material through them.

According to one aspect of the present invention a method of reinstating damaged drains or underground passages, especially, but not exclusively, drains of the so-

called pitch fibre type comprises the steps of: introducing a cable through the drain

or passage between adjacent access chambers, drawing a cutter or forming tool implement through the drain or passage to cut through material obstructing it or to reform the liner to shape, removing any debris, introducing a flexible liner into the section of the drain or passage between the said two access chambers and inflating 5 the flexible liner to bring it substantially into contact with the walls of the drain or passage, and thereafter causing the liner to cure or set to a substantially rigid form.

Drains or passages passing under buildings can thus be treated from two access chambers, one each side of the building, without necessarily disrupting the building 10 floor in order to gain access to the damaged drain. If the failure of the drain is due to a partial collapse of a pitch fibre drain which has not ruptured but merely deformed under pressure, it is possible in some circumstances to force it back to shape by passing a forming tool through between two access chambers before installing the new liner.

The method of the present invention may further include the step of introducing a closed circuit television camera into the drain or passage after having introduced the said cable, whereby to establish the location of obstructing material within the drain or passage.

As used in this specification, the term "cable" will be understood to refer to any

elongate tension-applying member suitable for drawing an item through an underground drain or passage, and includes rope, chain, hawser or other multi or monofiliment elongate elements.

In a preferred aspect the closed circuit television camera is also used to establish the location of lateral branches of the drain or underground passage. Openings in the liner prior to introduction thereof into the drain or passage may be made in

positions corresponding to the locations of the said side branches as identified by 5 the closed circuit television, and the liner is then drawn into the drain or passage to a position such that the preliminarily formed openings therein are located in register with the side branches. Alternatively, however, the liner may be left intact, and openings from the side branches made by use of a separate cutting tool after the liner has cured.

The initial introduction of the cable into the drain or passage may be achieved by

means of a pressurised water jet feed element. Such element advances by applying a pressurised water jet in advance of its motion to remove debris, and is urged in its direction of advance by rearwardly facing water jets. The action of these latter 15 also assists in clearing the drain or passage of debris. The pressured water jet produces a venturi effect to help flush the debris back along the pipe or drain. This may also be coupled with a brush or scraper.

Once the cable is in place a cutter may be drawn through the drain or passage 2 0 although, obviously, if the blockage is substantial it may be necessary to utilise a relatively small diameter cutter implement to make a small hole and subsequently exchange this for successively larger cutters so as to ream an opening through the obstruction.

Debris from the action of the cutter implement may be removed utilising a pressurised water jet drawn through the drain or passage by the cable, and this cleansing operation may be supplemented by a brush or scraper. The pressure jet may be applied by a self-propelled unit, however, which is not dependent on the 5 cable to be drawn through the drain or passage.

After the liner has set it may subsequently be trimmed to size at each access chamber before being recommissioned.

l o The present invention also comprehends apparatus for use in the maintenance of underground drains or passages, comprising a drum, means for supporting the drum in or above an access chamber to the underground drain or passage, an elongate cable wound on the drum, cable guide means for diverting the cable from the drum into an underground drain or passage, which cable guide means are adjustable in 15 height whereby to align the cable with a predetermined part of the cross section of the drain or passage. This takes account of the fact that drains may be laid at various different levels with respect to ground level, and accordingly the distance from the surface of the ground to a central horizontal plane through the cross section of the drain may differ from one access chamber to the next even on the 2 o same length of drain.

Preferably the cable diverter means are provided with a strain-resisting means engagable with the side wall of the or an access chamber to a drain or passage.

This allows the cable to be drawn through a drain applying a considerable force

simply by winding the cable back onto the drum in the manner of a winch, the guide means diverting the cable from a horizontal to a vertical path such that the strain-resisting means resists horizontal movement and the mounting of the apparatus on the ground resists vertical movement.

The means for diverting the cable from the drum into an underground drain or passage preferably comprises a pulley over which the cable passes. The pulley may be carried at the lower end of a support arm the length of which is adjustable in order to accommodate the above-mentioned variations in the depth of the access 1 0 chamber.

Adjustment of the said adjustable arm may be provided by course adjustment means for providing major adjustment movements, and fine adjustment means for accurate final positioning of the diverter.

The drum may be turnable manually or by means of a motor, and is preferably mounted on a support frame positionable over the location of an access chamber.

The said strain-resisting means preferably comprises a thrust pad supported on the 2 0 cable guide means, or an element supporting the said cable guide means.

The present invention also comprehends a cutter for use in restating the shape of an underground passage or drain, having a substantially continuous encircling blade the cutting edge of which is formed at or adjacent the outer perimeter thereof,

and means for attaching the cutter to a cable to be drawn in use through the underground passage or drain whereby to act on the walls of the passage or drain to reform them to the shape of the cutter.

5 The blade preferably has a cutting edge at each of two opposite ends thereof and is preferably substantially cylindrical in form with opposite circular edges which are formed as cutting edges.

A forming tool may have similar structure, but with a rounded edge instead of a 10 cutting edge.

In a preferred embodiment of the invention the cutter blade is carried on a support frame having draw connections at each end thereof. Such frame may have a central tension-resisting bar with shackles at each end for transferring the tension of a draw 5 cable thereto: Alternatively, however, the cutter blade may be carried on two orthogonal pairs of side frames.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: 2 0 Figure l is a side view of cable handling apparatus suitable for use in the method of the present invention and constituting an embodiment of the apparatus of the present invention; Figure 2 is a front view of the cable handling apparatus illustrated in Figure 1;

Figure 3 is a side view of a cutter implement suitable for use in forming the method of the invention, and Figure 3a is an enlarged view of the cutting edge of the blade; Figure 4 is an end view of the cutter illustrated in Figure 3; 5 Figures 5a to g are schematic side views illustrating successive steps in the performance of the method of the invention; Figures 6, 6A & 6B are side, sectional and end views respectively of a non cutting forming tool; Figures 7, 7A and 7B are a schematic side view, sectional view and end 10 view respectively of an alternative cutter tool; Figure 8 is a side view, similar to Figure 1, of alternative cable handling apparatus; and Figure 9 is a schematic side view of a part of the embodiment of Figure 8 in a different adjustment.

Referring now to the drawings the cable management apparatus illustrated in Figures 1 and 2 is generally indicated with the reference numeral 11 and is shown in position over an access chamber 12 to an underground drain or passage 13. The access chamber 12 may be a preliminarily installed manhole or may be a chamber 20 formed for the purpose of investigating the state of the underground drain or passage 13.

A drum 14 mounted on a spindle 15 turnable by a crank handle 16 is carried between two support plates 17, 18 mounted on a platform 19 which itself is carried

on four legs 20 with feet 21.

Below the platform 19 and spanning the legs 20 is a support plate 22 carrying aligned fixing eyes in the form of short lengths of tube 23, 24 through which passes 5 a removable cross pin 25 on which is carried an eye 26 at the upper end of a suspension arm assembly 27 the lower ends of which carries a diverter pulley 28 between two lugs 29 of a fork-like support (generally indicated 30) at the lower end of the support column 27.

1 0 The support column 27 itself comprises an upper section 31 to which the eye 26 is fixed and over which engages a lower section 32 which is telescopically adjustable along the length of the upper section 31. For coarse adjustment of the relative positions of the upper and lower sections 31, 32 there are provided a plurality of holes 33 engagable by a locating pin 34 passing through a slot 35 in the lower 5 section 32, and engaged by a threaded collar 36 which itself is adjustable along the length of the lower section 32 by means of its threaded engagement with an externally threaded part of the lower section 32, corresponding in length to the slot 35. Course adjustment of the length of the support arm assembly 27 can be effected, therefore, by removing the pin 34, adjusting the position of the lower 20 section 32 by telescophically sliding it with respect to the upper section 31, and reintroducing the pin 34 into the nearest available hole 33 in the upper section 31.

Fine adjustment of the length of the support arm assembly 27 is then achieved by rotating the collar 36 to raise or lower the lower section 32. In this way the height of the pulley 28 in relation to the chamber 12 can be adjusted so that the tangent to

the lower edge of the pulley (which determines the line of a cable passing over the pulley 28) can be brought into exact register with the horizontal plane of the centre line of a drain or passage opening into the access chamber 12.

5 Lateral adjustment of the position of the pulley 28 can be achieved by displacing the eye 26 laterally along the pin 25, again to vary the lateral position of the tangent to the pulley 28 whereby to bring it into exact register with the vertical plane of the centre line of the drain pipe 13. Although this has been illustrated as being located symmetrically within the chamber 12 it will be appreciated that, in practice, the lo access chamber 12 may not be exactly centred on the drain pipe 13 and it may be located somewhat off set from the centre line of the access chamber 12.

Projecting laterally from the bifocated pulley 29 are two support arms 37 which carry a thrust pad 38 which, as illustrated in Figure 1, can engage a side wall 39 of 15 the access chamber 12 for purposes which will become apparent hereinbelow.

The pulley 28 has two opposite side cheeks 40, 41 and a central circumferential groove 42 in a flat cylindrical surface 43 the diameter of which is slightly less than that of the side cheeks 40, 41 to provide guidance for a flexible liner tube as will 20 be described in more detail below. The central circumferential groove 42 accommodates a cable 44 which is turned through 90 by the pulley 28 and runs down from the drum 14 on which a length of the cable 44 is wound as can be seen in Figure 2.

Figures 3 and 4 illustrate a cuKer implement which may be drawn through the drain 13 by the cable 44 in performance of the method of the invention. The cuKer implement generally indicated 45 comprises a generally cylindrical cuKer blade 46 having opposite circular cubing edges 47, 48 formed by an internal bevel 49 (see 5 Figure 3a) formed around the circumference of each circular end of the cylindrical body 46.

The cutter blade 46 is carried on a support frame formed from eight identical frame arms 50 each secured in respective rebates 51 (see Figure 3a) in the peripheral edge 1 o of the cylindrical cutter body 46. The arms 50 are arranged in opposite pairs in a cruciform configuration at each end of the cuKer body 46 (see Figure 4) with the arms 50 having a curved main section 50a and a parallel end section 50b which, together, forms a box-section end portion closed by a rectangular end plate 52 at the respective ends of the cuKer implement. A respective shackle 53 is secured to 5 each box section end portion 50b at each end of the cutter implement 45, for attachment to the cable via a respective D-shackle 54.

As will be appreciated from a consideration of Figures 3 and 4, the cuKer implement 45 is shaped to pass through an obstructed drain with the inclined 2 0 portions 50a of the support arms 50 causing the minimum resistance to movement, and the cubing edge 47, 48 at the leading end of the cuKer body 46 (depending on the direction of movement of the cuKer implement 45 through the drain) axe to shave the surface of the wall of the drain wherever it meets this wall, removing the material and leaving it loosely within the drain passage for subsequent removable.

In order to enlarge an obstructed drain a range of sizes of cutter implement 45 may be provided in order to maintain the forces required to draw the cutter implement through the drain to manageable levels.

5 The method of the invention for reinstatement of a damaged drain will now be

described in relation to Figure 5, illustrating the use of the apparatus described in relation to Figures l to 4: first, as illustrated in Figure Sa, two spaced access chambers 10, 12 at opposite ends of a section of obstructed drain 13 are located. These may be 10 permanent manholes provided upon the original installation of the drain or may be specially formed access chambers made for the purpose in hand. In the following description it will be assumed that the drain has partly or entirely collapsed such

that an obstruction 60 is located at a point between the two access chambers 10, 12.

First, the winch apparatus 11 is set up over the access chamber 12 and the pulley 5 28 positioned approximately in line with the centre of the drain 13. Then, from the chamber 10, a pressure jet cutter acting to project a high pressure forward jet to dislodge the material in the obstruction 60, and having rearwardly facing jets for propulsion purposes, is introduced into the drain 30 via the access chamber 10 and caused to pass along the drain 30, cutting its way through the obstruction 60, by 2 0 applying water under high pressure along a pressure line 62. The broken line 63 in Figure 5a illustrates the intended path of the pressure jet cutter implement 61.

When it arrives at the access chamber 12 this cutter implement can be removed from the delivery line 62, and the cable 44 from the drum 14 attached to its other end and drawn through. This may be achieved either by withdrawing the delivery

line 62 and paying off cable 44 from the drum 14, utilising a separate winch (not illustrated) at the access chamber 10, or alternatively by wounding the delivery line 62 onto the drum 14, drawing the cable 44 through the drain 13 from a supplied drum (not shown) thereof at the access chamber 10 until it reaches the access 5 chamber 12 at which point the delivery line 62 is removed from the drum 14 and the cable 44 wound onto it.

Once the cable 44 has been inserted into the drain 13, a closed circuit television camera 64 is attached to the cable 44 and drawn through the drain 13 to investigate 1 o the state of the internal walls of the drain 13, locate the blockage and any "laterals", that is side branches to the drain 13.

Having performed this operation, the camera 64 is then extracted from the drain 13 and, as illustrated in Figure 5c a cutting implement 45 such as that illustrated and 5 described in relation to Figures 3 and 4, is attached to the cable 44 and drawn through the drain 13 by winding the cable 44 onto the drum 14 using the crank handles 16. In performing this operation, the considerable forces exerted on the cutting implement 44 by drawing it through the blockage 60 are resisted by the thrust pad 38 which engages the side wall 39 of the access chamber 12.

2 o Centralisation of the cutting implement 45 within the drain 13 is ensured by the accurate positioning of the pulley 28 by vertical adjustment utilising the threaded collar 36 and lateral adjustment of the eye 26 along the pin 25. If the blockage 60 is of considerable magnitude a series of successively larger cutting implements 45 may be used, drawing the cutting implement through the section of drain 13

between the two access chambers 10, 12 until having reinstated the maximum bore of the drain pipe 13. Then, as illustrated in Figure 5d, a pressure jet washing implement 65 is drawn through the drain 13 with an associated brush (not illustrated) to wash out and remove the debris from the cutting operation. This, 5 then, leaves the drain 13 reinstated to its original diameter but having earth walls in places where a collapsed or foiled liner has been removed, and which may collapse if not reinforced. At this stage, as illustrated in Figure Se, the closed circuit television camera 64 may again be linked to the cable 44 and drawn through the drain 13 in order to review the bore of the pipe and ensure that the wall has 10 been properly cut to the desired state. Thereafter, as illustrated in Figure Sf a prepared, resin impregnated tubular liner having a diameter matching that of the drain 13, is drawn through the drain 13 from the chamber 10 to the chamber 12 utilising the winch apparatus 11. In doing so the liner rides over the wide cylindrical surface 43 of the pulley 28 provided for supporting a tubular element 5 of this dimension. Once the liner 66 has been drawn into the drain 13 it is expanded by the introduction of water or air under pressure, the leading end 67 of

the liner 66 being closed as illustrated in Figure Sg. This pressure is maintained until the impregnating resin cures or sets to maintain the liner in its desired expanded configuration, where after the ends of the liner are trimmed of and a final 2 o inspection through the now fully reinstated bore of the drain 13 is carried out.

If there are any laterals these may be opened by utilising a cutter introduced through the lateral and having a forward-facing cutter blade acting to enter the

drain 13 from the lateral.

The method of the invention may also be put into effect using a forming tool rather than a cutter. A suitable forming tool is shown in Figures 6, 6A & 6B. A 5 cylindrical former 71 is carried on two sets of four relatively inclined arms 72, 73.

A central rod or bar (not visible in the drawings) passes down the centre of the tool between opposite ends 74, 75 having respective eyes 76, 77 for connection via shackles 78, 79 to a cable. As can be seen in Figure 6A the outer surface of the cylindrical former 71 is rounded to assist, together with the shallower taper of the l o arms 72, 73 in opening out a collapsed liner as the forming tool is drawn through it. It is also possible to make use of a cutting tool having a rotating blade or cutter, turning about an axis parallel to the length of the drain or pipe, especially to cut 15 into a reinstated liner (once cured or set) from a lateral, or to allow a reinstatement

operation to be undertaken on a part only of length of a drain between two adjacent access chambers. If for example, a significant part of the drain, when inspected, does not need any remedial action, it is possible to introduce a liner with a closed leading end into only that part of the drain in need of remedial action, using the 2 o techniques and equipment described above. After the liner has set the closed end may be cut away using a cutter tool having a rotating cutter and then the debris cleared away using a water jet.

Figures 7, 7A and 7B show an alternative embodiment of the cutter tool of the

invention which, unlike the tool illustrated in Figure 3, is intended to act only when drawn through the drain pipe in one direction, namely from left to right as shown in Figure 7, as represented by the arrow A. In this embodiment a central cylindrical body 80 is carried by two sets of four arms, namely a leading end set 8 l 5 and a Mailing end set 82. The leading end arms 8 l are joined together at a leading end 83 to an eye 84 and diverge outwardly from the eye 84 to the point connection with the cylinder 80. The trailing end arms 82 converge from their connection with the cylindrical body 80 to a rearward connection to a trailing eye 85. The leading end arms 8 l carry respective incisor blades 86 having two radially offset crests 80, 10 89. The blades 86, 87 lie in a radial plane including the arm on which it is carried.

A cylindrical cutter body 90 is carried by the converging trailing end arms 82 on suitable supports (not illustrated) extending radially therefrom, and has a sharp 15 cutting edge 9l formed by a radially internal bevel 92. It is intended that the cutter tool illustrated in Figure 7 shall be used by being drawn only in the forward direction by the eye 84, the eye 85 being connected to a line or cable which is drawn through the drain by the cutter tool to allow either reverse pull through of the driving cable, or, by reversing the connections of the cutter tool, reverse cutting 2 0 utilising the same tool.

An alternative embodiment is illustrated in Figures 8 and 9 in these figures those components which fulfil the same or corresponding functions to previously identified components in the embodiment of Figures l and 2 will be identified with

the same reference numerals.

The four legs 20 of embodiment of Figures 1 and 2 which constituted the entirety of the support frame carrying the platform 19 have, in this embodiment, been 5 replaced by upper and lower support frames 100, 101 respectively. The upper support frame 100 comprises the four legs 20 carrying an upper plate 98 onto which the platform 19 can be located by means of downwardly projecting pins 97 which engage in corresponding apertures in plate 98. The lower ends of the legs 20 are joined by a frame 93 which is carried on the upper frame 94 of the lower 10 support 101 via pins 96 passing through holes (not shown) in the frame 94. The frame 94 is carried on four lower legs 95 which are positioned so as to be aligned with the upper legs 20 when the frame is assembled. This structure allows rapid and easy assembly of the component parts, without requiring mechanical fixings, and facilitates dismantling after use since the component parts can simply be lifted 5 from one another.

The column 27 of the embodiment of Figures 1 and 2 has been replaced by a composite column 102 comprising an upper tube 103 and a lower tube 104 each having respective sets of transverse holes 105, 106. A central tube 107 20 telescopically receives the upper and lower tubes 103, 104 and these can be engaged in selected positions by pins 108, 109 passing through holes (not visible in the drawings, but identified by the position of the pins 108, 109) closely adjacent the ends of the tube 107. The pins 108, 109 have manipulating handles 110, 111.

This configurations allows a greater range of adjustment than the embodiment of Figures 1 and 2 since the coarse adjustment of the length of the column 102 is made by selection of an alternative outer tube 107 from a range, and the fine adjustment made by the selection of the holes 105, 106 through which to pass the 5 pins 108,109. The spacing of the holes 105 and/or 106 from one another is sufficiently close to allow an adequately precise fine adjustment for the purpose.

The lower fork 29 carrying the pulley 28 can now be made turnable on the lower tube 106 of the column 102 so that slight misalignments between the apparatus and 10 the bore 13 can be accommodated, and the precise width of the cavity 12, which may of course vary from time to time, can be accommodated by an adjustable pressure leg 112 carrying the pressure pad 38. Again, this adjustment is made by interchangeable tube sections 112 to vary the distance from the pad 38 to the pulley 28. Figure 9 shows relevant components for a cavity 12 which is deeper and wider than the corresponding cavity shown in the embodiment figure 8.

Claims

1. Apparatus for use in the maintenance of underground drains or passages, comprising a drum, means for supporting the drum in or above an access chamber 5 to the underground drain or passage, an elongate cable wound on the drum, cable guide means for diverting the cable from the drum into an underground drain or passage, the said cable guide means being adjustable in height whereby to align the cable with a predetermined part of the cross section of the drain or passage.

o

2. Apparatus as claimed in Claim 1, in which the cable diverter means are

provided with a strain-resisting means engagable with a side wall of the or an access chamber to a drain or passage.

3. Apparatus as claimed in Claim 1 or Claim 2, in which the means for 5 diverting the cable from the drum into an underground drain or passage comprises a pulley over which the cable passes.

4. Apparatus as claimed in Claim 1 or Claim 2, in which the diverter means is carried at the lower end of a support arm the length of which is adjustable.

5. Apparatus as claimed in Claim 4, in which the said adjustable arm is provided with coarse adjustment means for providing major adjustment movements, and fine adjustment means for accurate positioning of the diverter means.

6. Apparatus as claimed in any of Claims 1 to 5, in which the drum is manually turnable to pay off or draw on cable.

5

7. Apparatus as claimed in any of Claims l to 5, in which the drum is driven by motor means to pay off or tension the cable.

8. Apparatus as claimed in any of Claims 1 to 7, in which the drum is mounted on a support frame positionable over the location of an access chamber.

9. Apparatus as claimed in any of Claims 1 to 8, in which the said strain resisting means comprise a thrust pad supported on the cable guide means, or an element supporting the said cable guide means.

5

10. Apparatus as claimed in any of Claims 1 to 9, in which the means supporting the cable guide means are dismountable for transport and/or storage.

11. Apparatus for use in the maintenance of underground drains or passages, substantially as hereinbefore described with reference to and as shown in the 2 0 accompanying drawings.