GB2470923A

GB2470923A - A drainage device for draining water from a drainpipe

Info

Publication number: GB2470923A
Application number: GB0909911A
Authority: GB
Inventors: Andrew Colin Hartley
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-06-10
Filing date: 2009-06-10
Publication date: 2010-12-15
Also published as: GB0909911D0

Abstract

The invention relates to a drainage device 1 for draining rain water from a drainpipe 3 and comprises a conduit 5 having a first end 11 and a second end for channeling the water from the drainpipe. The conduit includes at least one aperture 7 between the first and second ends for receiving the water to be channeled. The device further comprises an anchor 9 having an attaching portion for attaching the anchor to the drainpipe and a coupling portion (61 figure 4) for coupling to the first end of the conduit. The device also has a clamping device 13 with at least one formation for attaching the clamping device to the pipe and a clamp for clamping the conduit between the first and second ends. The clamping device may comprise a gland assembly with a gland body, a gland nut (25 figure 3) and a collet (27 figure 3). Later embodiments relate to a kit of parts comprising said drainage deice and a method of installing said device.

Description

A Drainage Device This invention relates to a drainage device for draining liquid from a pipe. In particular, the invention relates to a drainage device for draining water from a drainpipe.

Most modern buildings have a drainage system to remove rainwater from the roof of the building. Typically, for a pitched roof, a drainage system includes an open gutter located along the edge of the roof inclined so as to direct collected water to a downpipe. The downpipe can channel water to a subterranean drain linking to a drain infrastructure or simply to a local naturally well drained location. In this way rainwater is safely and efficiently removed to prevent any hazard or nuisance to the users of the building or damage to the building itself.

An alternative to disposing rainwater down a drain is to collect and store the rainwater from the drainage system. The stored water can then be used for any desired purpose such for watering of plants and vegetables in a garden or flushing a toilet, neither of which requires a high quality of filtered water.

Apparatus and systems for collecting rainwater from the drainage systems are known.

Known systems include a coupler which joins two ends of a vertical drainpipe having a gutter formation within to capture the rainwater and a pipe to channel the rainwater to a storage device. These types of device are difficult to install as they require one or two perpendicular cuts of the vertical drainpipe to provide the two ends for the coupler. This can prove to be difficult for a lot of end users, particularly when the drainpipe is fixed to a wall. Further, when the water butt is no longer wanted and the coupler removed, a new piece of drainpipe is required to rejoin the two ends of the drainpipe.

Another known includes a perforated pipe positioned in a vertical drainpipe. The perforated pipe has a helical configuration having several turns prior to being installed in the drainpipe. The greatest transverse dimension of the helix is greater than the internal diameter of the drainpipe such that the helix is compressed when the perforated pipe is placed in the drainpipe. The conipression creates a restoring force against the wall of the drainpipe which acts to hold the perforated pipe in place.

Relying on the restoring force of the compressed helix can be unreliable due to the failing elastic memory of the plastic used for the perforated pipe. Further, the system requires several turns of pipe to be effective which can lead to difficulty in installing and correctly positioning the perforated pipe. Although the system can be installed without damage to an existing drainpipe, installation requires an open end in to which the coiled perforated pipe can be fitted. This means either the drainpipe must be disassembled at a joint or installation of the perforated pipe must be carried out at the open bottom end. Installing the pipe from the bottom end can severally restrict the position of the outlet of the perforated pipe.

Another limitation of this type of system is it can only be used effectively on drainpipe having a circular cross-section.

The present invention seeks to overcome the problems identified with the prior art and provide a drainage system which is easy to install without significant damage to an existing drainage system.

In a first aspect, the present invention provides a drainage device for draining liquid from a drainpipe comprising: a conduit having a first end and a second end for channelling liquid from the drainpipe including at least one inlet between the first and second ends for receiving the liquid to be channelled; an anchor having an attaching portion for attaching the anchor to the drainpipe and a coupling portion for coupling to the first end of the conduit; and a clamping device having at least one formation for attaching the clamping device to the pipe and a clamp for clamping the conduit between the first and second end.

Fixing a length of conduit with an inlet in a drainpipe between an anchor and a clamp allows for a good, maintainable contact to be achieved between the conduit and the inner surface of the drainpipe. Liquid travelling on the inner surface of the drainpipe can enter the inlet and be channelled away. Further, because it is possible to position the conduit before clamping it in place, accurate positioning of the conduit in drainpipes of different profiles is possible.

The pipe can be any drainpipe into which the conduit can be installed using the drainage system. Preferably, the drainpipe is part of a rainwater drainage system on a building. The drainpipe can be inclined at an angle to the vertical. Preferably, the drainpipe is substantially vertical.

The cross-section of the drainpipe can be polygonal. For example, the cross-section of the drainpipe can be square or rectangular. The cross-section of the drainpipe can be round.

For example, the cross-section of the drainpipe can be circular or oval.

The drainpipe can be made from metal. Preferably, the drainpipe can be made from a polymer. The skilled person will be aware of suitable polymers and metals and associated methods of manufacture.

The thickness of the drainpipe wall can be greater than about 1 mm. The drainpipe wall thickness can be greater than about 2mm.The drainpipe wall thickness of the drainpipe can be less than 6mm. Preferably, the drainpipe wall thickness is less than 3mm. More preferably, the drainpipe wall thickness is about 2mm.

The conduit is a member suitable for channelling liquid. Preferably, the conduit is a tube.

The tube can be a half-pipe having a semi-circular cross-section. Preferably the tube has a round cross-section. Preferably, the tube inlet between the first and second end is an aperture for allowing water to enter the tube.

Preferably, the inlet will be at least one aperture. The aperture can be a through-hole in the wall of the conduit. The aperture can be polygonal. For example, the aperture can be square or rectangular. The aperture can be round. For example, the aperture can be circular or elliptical. The aperture can be an elongate opening.

The number of apertures can be 1 or more. The number of apertures can be less than 30.

The number of apertures can be greater than 5. The number of apertures can be less than 25. The number of apertures can be greater than 10. The number of apertures can be less than 20. Preferably, the number of apertures is about 15.

Preferably, a plurality of apertures are positioned along a longitudinal axis. The plurality of apertures can be arranged so as to radially traverse the tube wall along the length of the longitudinal axis so that when the tube is formed into a helix of predetermined dimensions about a central axis the apertures are oriented in a common direction relative to the central axis.

The conduit can include a first visual indicator to show the orientation of the apertures relative to the drainpipe when the drainage device is being installed. Preferably, the first visual indicator is a line on an outer surface of the conduit running coaxially with the apertures.

The conduit can include a second visual indicator. The second visual indicator can be placed at a predetermined position from the first end of the conduit so that the amount of tube within the drainpipe can be known. The visual indicator can be a radial line on the surface of the tube.

The conduit can be made from metal. The conduit can be made from a polymer. Examples of suitable metals and polymers and associated methods of manufacture will be known be the skilled person. The apertures can be formed when the conduit is being manufactured.

The apertures can be made in an existing conduit.

Preferably, the inside of the conduit is substantially impervious to light. The conduit can include a inhibitor to inhibit the growth of organic matter.

Preferably, when installed in a drainpipe the tube is arranged so as to have a helical configuration. Preferably, the helix includes at least one half turn. More preferably, the helix includes at least 0.8 of a turn. More preferably still, the helix includes approximately one full turn. More preferably still, the helix includes 1.2 turns. The helix can include more than 1.2 turns.

The ratio of the pitch of the helix to the internal diameter of the pipe can be less than about 2. The ratio can be less than about 1.5. The ratio can be less than about 1. Preferably the ratio is about 0.8. The ratio can be greater than 0.4. The ratio can be greater than about 0.7.

The conduit can have a wall thickness greater than about 0.5mm. Preferably, the conduit has a wall thickness greater than about 1 mm. More preferably, the conduit has a wall thickness of about 1.5mm. The conduit can have a wall thickness less than about 4mm.

Preferably, the conduit has a wall thickness less than about 3mm. More preferably, the conduit has a wall thickness less than about 2mm. The wall thickness of the conduit can be substantially constant along the length of the conduit.

The inner bore of the conduit can be greater than about 1mm. The inner bore of the conduit can be greater than about 3mm. The inner bore of the conduit can be greater than about 5mm. The inner bore of the conduit can be less than about 15mm. The inner bore of the conduit can be less than about 10mm. More preferably, the inner bore of the conduit can be less than about 6mm. Preferably, the inner bore is about 8mm.

Preferably, the external diameter of the conduit is about 10mm when the conduit has a circular cross-section.

Preferably, the tube has a constant cross-section along the length of the tube.

The formation for attaching the clamping device can include a flexible member which at least partially encircles and grips the pipe. The flexible member can be a band of material having elastic properties. Preferably, the flexible member is a strap. More preferably, the clamping device includes a plurality of formations. More preferably still, each formation is a flexible member or arm in the form of a strap.

The clamp acts to retain the conduit within the pipe. The clamp can be a vice. The vice can include formations with opposing faces arranged to radially compress the conduit.

Preferably, the clamp is arranged so as to define a passageway for the tube to pass through.

The clamp can include a collar through which the conduit can pass. The collar can be part of a gland assembly. The collar can include a threaded stud which can be tightened so as to radially compress the conduit within the collar thereby clamping the conduit.

Preferably, the gland assembly can include a collet and a gland nut in which tightening the gland nut compresses the collet thereby gripping the conduit. The collet can be made from any suitably deformable material. Preferably, the collet is made from rubber.

The components of the clamp can be made from one or more polymers. Examples of suitable polymers and associated methods of manufacture will be known to the skilled person. The flexible members may include metal.

The clamping device can include a guiding portion arranged to align the conduit along a predetermined path. The guiding portion can be the passageway defined by the clamp.

Preferably, the guiding portion is the collet.

Preferably, when the drainage device is installed in a drainpipe having a circular cross-section, the clamping device is arranged so as to define a passageway for the conduit to pass through which is tangential to the drainpipe wall when viewed along the longitudinal axis of the drainpipe when positioned for normal use. With this arrangement, the conduit can contact the drainpipe wall within the drainpipe proximate to the clamping device.

The anchor can include a formation which can snugly engage within a hole of predetermined diameter in the drainpipe. Preferably, the anchor can be an integral part of the tube. The attaching portion can be a formation at the first end of the tube. The tube can include the coupling portion.

The coupling portion of the anchor can include a push fit connector for connecting to an aperture in the pipe. The push fit connector can include at least one gripping formation for insertion into the end of the tube. Preferably, the gripping formation includes a barbed formation.

Preferably, the coupling portion comprises a member having a longitudinal axis to which the first end of the tube can be attached. Preferably the member includes the gripping formation.

Preferably, the anchor and clamping device are inclined with respect to vertical when located in a drainpipe in predetermined positions relative to each other so that the longitudinal axis of the coupling portion member and a longitudinal axis of the passageway in the clamping device are coaxial around the inner surface of the drainpipe so as to define a pathway the for the conduit to be located on.

In a second aspect, the present invention provides a drainage system comprising: a substantially vertical drainpipe having an inlet for receiving liquid, an outlet and a longitudinal axis, which includes a first hole and a second hole in which the first hole is positioned closer to the inlet than the second hole with respect to the longitudinal axis of the drainpipe; an anchor attached to the first hole and having the first end of a conduit attached thereto inside the drainpipe; a clamping device attached to the drainpipe having a clamp proximate to the second hole through which the conduit passes and is clamped, in which the tube has a substantially helical configuration between the anchor and the clamping device with an outer wall of the tube in contact with the inner surface of the drainpipe, the conduit including at least one inlet arranged so as to receive liquid from the inner surface of the drainpipe such that the liquid is channelled to a second end of the conduit located outside of the drainpipe.

The portion of outer wall of the tube in contact with the inner surface of the drainpipe extends along above about 50% of the length of the tube which is housed within the drainpipe. Preferably, the portion of outer wall of the tube in contact with the inner surface of the drainpipe extends along above about 70% of the length of the tube. More preferably, the portion of outer wall of the tube in contact with the inner surface of the drainpipe extends along above about 85% of the length of the tube.

Preferably, the drainage system can include a storage vessel in fluid communication with the second end of the conduit for storing liquid channelled by the conduit. The storage vessel can be internal to a building. Preferably, the storage vessel is on the outside of a building. More preferably, the storage vessel is a water butt.

In a third aspect, the present invention provides a kit of parts including the drainage device according to the first aspect.

Preferably, the kit of parts includes a substantially rigid member having a formation at one end for attaching toward an end of the conduit. The rigid member can act as a needle to thread the tube in the first hole in the wall of a drainpipe and out of a second. Preferably, the formation is a nub or hook for releasably attaching to an aperture located toward the second end conduit. The guide member can be comprise two or more straight portions arranged along different axes. Preferably, the guide member includes a curved portion.

Preferably, the kit of parts includes a drill template having predetermined marks suitable for indicating the relative position of a first hole for receiving the anchor and a second hole for location of the clamping device so that when the drainage device of the invention is installed, the conduit has a substantially helical configuration.

The kit of parts can further include a bung for sealably inserting into a hole in the drainpipe wall. Preferably, the kit of parts includes at least two bungs. The bungs can be used to seal the holes in the drainpipe in which the drainage device has been installed once the drainage device has been removed.

In a fourth aspect, the present invention provides a method of installing a conduit in a drainpipe for channelling water to the outside of the drainpipe via the conduit in which the drainpipe is in a substantially vertical position, the method comprising the steps of: boring a first hole in the pipe; boring a second hole in the pipe at a position vertically lower than the first hole; attaching an anchor to the first end of the conduit; passing the second end of the conduit into the first hole and out of the second hole; attaching the anchor to the drainpipe such that the first end of the drainpipe is fixed relative to the pipe; passing the second end of the tube through the clamp of a clamping device and attaching the clamping device to the drainpipe so that the clamp is proximate to the second hole; feeding the conduit back into the second hole so that the inner surface of the drainpipe and an outside surface of the conduit come into contact; and clamping the conduit with the clamp so as to retain the conduit within the drainpipe in contact with the inner surface.

S The method of the present invention allows a drainage system to be installed in a pipe using Iwo holes. This provides a simple installation which avoids irreparable damage to the drainpipe. This has the advantage that the holes can be bunged if the drainage device is ever removed to retain the functional capacity of the pipe.

The method can further comprise putting the second end of the conduit into a storage vessel for collecting and storing liquid collected from the pipe.

Embodiments of the invention are now described by way of example only and with the aid of the following drawings in which: Figure 1 shows a side view of an embodiment in which the drainage device is located within a vertical drainpipe.

Figure 2 shows a top view of the drainpipe of the embodiment from direction A as shown in Figure 1.

Figure 3 shows a cross-section of the clamping device of the embodiment.

Figure 4 shows a cross-section of the anchor of the embodiment.

Figure 5 shows a side view of a helical path between the clamping device and anchor of the embodiment.

Figure 6 shows a drainage system which includes the drainage device of the embodiment.

In Figures 1 and 2 there is shown a drainage device 1 within a vertical drainpipe 3 having a circular cross-section. The drainpipe 3 is part of a domestic drainage system used for draining rainwater from the roof of a domestic property. The drainpipe has an external diameter of 68mm and connects a roof gutter to a ground drain. The wall thickness of the drainpipe is approximately 2mm. An example of the drainage system can be seen in Figure 6 which is described in more detail below.

The drainage device 1 includes a conduit 5 in the form of a tube 5. The tube 5 is held between an anchor 9 and a clamping device 13. An anchor 9 which is inserted through and held within a first hole in the drainpipe wall anchors a first end 11 of the tube 5 relative to the drainpipe 3. A clamping device 13 mounted to the outside of the drainpipe 3 below the anchor 9 proximate to a hole in the drainpipe wall through which the tube 5 passes, clamps the tube 5 between the first 11 and second end (not shown) of the tube 5 50 as to retain the tube 5 within the drainpipe 3 in a fixed substantially helical configuration. Thus, the tube 5 has a continuous downward trajectory allowing any water within to flow along its length towards the second end of the tube 5.

An outer edge 17 of the tube 5 is in contact with the inner surface 19 of the drainpipe 3 for the majority of the length of the tube 5 within the drainpipe 3. The tube 5 has inlets in the form of a plurality of apertures 7. The apertures 7 are positioned along the top of the tube 5 and are orientated towards the inner surface 19 of the drainpipe 3. Hence, water running down the inner surface of the drainpipe 3 can enter the tube 5 through the apertures 7 and be channelled toward the second end to the tube 5. The second end of the tube 5 is in fluid communication with a storage vessel in the form of a water butt as shown in Figure 6.

The anchor 9 and clamping device 13 are fixed to the drainpipe 3 as described in more detail below. Hence, the tube 5 is fixed at both ends with one end higher than the other.

Because both ends of the tube 5 are fixed relative to the drainpipe 3 contact between the outer edge 17 of the tube 5 and inner surface 19 of the drainpipe 3 can be maintained.

Further, the clamp allows a good contact to be attained between the tube 5 and drainpipe before the clamp is tightened. This helps reduce any gaps between the tube and the inner surface 19 of the drainpipe so as to help prevent water bypassing the drainage device.

The contact between the tube 5 and the inner surface of the drainpipe 3 provides a trough on the outside of the tube 5. If the flow of water is biased on one side of the drainpipe and the available apertures 7 directly in that area are swamped, water can flow around the helix in the trough to the next available aperture 7.

The tube 5 is made from nylon and is semi-rigid. The skilled person will appreciate that other materials may be used and the rigidity may be selected to suit a given drainpipe diameter or configuration. The outer diameter of the tube 5 is 10mm. The inner diameter of the tube 5 is 8mm. This material and dimensions provides a suitable degree of flexibility in the pipe whilst being strong enough to accommodate the apertures 7 without substantially deforming cross-section of the inner bore when in a helical configuration.

The apertures 7 can be selected to suit the size and configuration of the tube 5 and drainpipe 3. Further, the apertures 7 can be selected so as to prevent large foreign objects entering the tube, such as leaves. In the shown embodiment the apertures 7 are circular and evenly spaced along the length of the tube 5 which is housed within the drainpipe 3. The diameter of the apertures 7 is 8mm.

Figure 3 shows a cross-section of the clamping device 13 which includes a clamp 15 in the form of a gland assembly 15 and two formations for attaching the clamping device 13 to the drainpipe 3 in the form of flexible members or arms.

The gland assembly 15 comprises a gland body 23, a gland nut 25 and a collet 27.

It is desirable to have the tube 5 enter the drainpipe 3 so as to make contact with the inner surface 19 as soon as possible, thus reducing any gaps between the inner surface 19 of the drainpipe 3 and the tube 5. The gland assembly 15 defines a cylindrical passage through which the tube 5 passes. The face 24 of the gland body 23 which mates with the outer surface 26 of the drainpipe 3 is located at the proximal end of the gland body 23. The face 24 is shaped so that the gland assembly 15 sits on the drainpipe 3 with the passage substantially tangential to the inner surface 19 of the drainpipe 3 when viewed from above.

Hence, the tube 5 can pass smoothly through the clamping device 13 and on to the inner surface 19 of the drainpipe 3 and contact between the outer surface 17 of the tube 5 and the inner surface 19 of the drainpipe 3 is achieved proximate to the second hole through which the tube 5 passes.

The gland body 23 is a hollow cylinder having three coaxial portions arranged in series.

The internal surface of the first portion 31 is threaded so as to receive the gland nut 25. The second portion 33 has smooth internal walls towards the distal end. The collet 27 is located in the second portion 33 and first portion 31. The third portion 35 is narrower than the first two portions so as to loosely house the tube 5 and occupy the remaining length of the body up to the drainpipe 3. The difference in the diameters between second 33 and third portions provides a shoulder 37 for the collet 27 to sit on.

The gland nut 25 is a hollow cylinder with a smooth inner surface 19 of sufficient diameter to loosely accommodate the tube 5. The outer surface of the gland nut 25 is threaded so that it can engage with threaded portion of the gland body. At a distal end of the gland nut there is located a hexagonal formation suitable for engaging with a tool for tightening the gland nut.

The collet 27 is a cylindrical resiliently deformable member made from rubber having a central through-hole for snugly accepting the tube 5. The proximal face of the collet 27 sits on the shoulder 37 between the second portion 33 and third portion 35. The proximal face of the gland nut 25 contacts the collet 27 via a metal washer (not shown) so that screwing the gland nut 25 into the gland body compresses the collet and clamps the tube 3.

The tangential engagement of the gland body 23 with the drainpipe 3 provides the gland body 23 with one side longer than the other in the third portion 35. At the proximal end of the longer side of the gland body 23 there is a foot portion 39 located on the face of the gland body 23 which extends in to the second hole. The foot portion 39 extends around the face of the gland body 23 by an arc of approximately 30 degrees. The function of the foot portion 39 is to help keep the clamping device 13 in place whilst the clamping device is attached to the drainpipe. The size and position of the foot portion 39 is such that it does not obscure the tubes 5 passage into the drainpipe 3. Although the collet 27 of the embodiment is made from rubber, the skilled person will appreciate other suitable materials can be used.

The clamping device 13 also comprises an attachment mechanism in the form of two flexible members 41 each attached at a first end to the gland body 23. The flexible members 41, or arms, are formed so as to fit around the drainpipe 3 thereby forming a collar to clamp around the drainpipe 3. The arms 41 are resiliently deformable so that they can be manually forced apart so as to be fitted around the drainpipe 3. The second end of each arm includes a plate member 43 which opposes the plate member 43 of the other arm 41. Each plate members 43 have through-holes which are coaxial when the arms 41 are in situ so that a bolt 45 can be received between the two plate members and tightened so as to fix the clamping device 13 in place.

The clamping device is made from plastic. The skilled person will appreciate from the described requirements of the clamping device which plastics would be suitable and how they could be appropriately manufactured.

Figure 4 shows an example of an anchor 9 having an attaching portion 49 including a seal member 47, and a coupling portion 51 in the form of an elongate member.

The attaching portion 49 comprises a body portion 51 for coupling to the sealing member 47. The body portion 51 comprises first plate 53 which is located on the outside of the drainpipe 3. A cylindrical projection 55 extends coaxially from the first plate 53 toward the interior of the drainpipe 3. The diameter of the projection 55 is approximately a quarter of that of the first plate 53. A second plate 57 having a diameter approximately half that of the first plate 53 is located on the end face of the projection 55. An arm member 59 extends radially toward the interior of the drainpipe 3 from a first end which is attached to the face of the second plate 55. The arm member 59 has a 90 degree bend and is arranged to project at an inclined angle alpha with respect to horizontal so as to have a longitudinal axis which directs the tube 5 around the inner edge of the drainpipe 3 towards the second hole.

The second end of the arm member 59 includes a coupling portion 61 in the form of a series of coaxial barbed formations 63.

The sealing member 47 provides a means for attaching the attaching portion 49 to the drainpipe 3 and for sealing the first hole so as to prevent water escaping. The sealing member 47 fits around the body portion 51 of the engaging member 49 to form a collar around the projection 55 and second plate 57 of the body portion 51. The inner portion of the seal member 47 which is exposed to the interior of the drainpipe 3 includes a tapered portion 65. The tapered formation allows the engaging member 49 to be inserted into the first bore with a greater ease.

When the clamping device 13 and anchor 9 are fixed in place the tube 5 must be positioned within the drainpipe 3. In order for the drainage device 1 to work effectively, a majority of the edge 17 of the tube 5 must be in contact with the inner surface 19 of the drainpipe 3. If this is not done successfully, water running down the inner surface 19 will simply bypass the tube 5. Further, the apertures 7 must be correctly positioned so as to accept and retain any water within the tube 5. Further still, the tube 5 needs to have a constant downward trajectory within the drainpipe so as to allow water to flow along its length. Having the tube 5 in a substantially helical configuration is simplest way to meet these objectives.

To assist in correctly positioning the tube 5 in a helical configuration within the drainpipe 3, the gland assembly 15 is angled upwards toward the anchor and the coupling portion of the anchor downwards toward the gland assembly so as to define a coaxial helical path 48 around the inner surface 19 of the drainpipe 3 between the clamping device 13 and the anchor as shown in Figure 5. Hence, the tube 5 can be fed in through the clamp 15 and contact the drainpipe wall in its most stress free state when on the helical path.

Once the tube 5 contacts the inner surface 19, a greater pressure can be applied along the longitudinal axis of the tube 5 from the second end prior to tightening the gland nut 25.

This allows a good contact to be achieved which helps reduce any gaps between the inner surface 19 of the drainpipe 3 and the tube 5.

It is important that the apertures 7 are in the correct position along the length of the tube 5 relative to the inner surface 19 of the drainpipe 3. If they are not in the correct position, the water will either not enter the tube 5 or enter the tube 5 and subsequently drain out.

When a straight tube 5 is formed into a helix, the tube naturally undergoes a torsional rotation. If the tube 5 is twisted as it is inserted into the drainpipe 3 the effects of the torsional rotation can be countered. However, this puts the tube 5 in a stressed condition which may hinder its correct positioning. If the apertures 7 are placed along a single axis along the length of the tube 5, the axis can gradually rotate around the tube 5 to account for the twist induced by the helical configuration. The rotation required in the axis will depend on the diameter of the drainpipe 3 and the vertical separation of the anchor 9 and clamping device 13. If the helix is in the clockwise direction viewed from above, then the rotation of the axis around the wall of the tube 5 must be clockwise when viewed from the second end. The rotation of the axis can be calculated empirically for different standard sizes and configuration of drainpipes.

To assist in keeping the apertures 7 are on the top side of the tube 5 when in place, a visual indicator in the form of a line is printed on the top of the tube 5 along the axis of the apertures 7. A corresponding mark is also placed on the gland assembly 21 so that aligning the line and mark when the tube 5 is being re-inserted into the drainpipe 3 prior to clamping the tube 5 will keep the tube 5 in the correct orientation. The anchor 9 also includes a marker so that the tube 5 is correctly positioned on the anchor 9 at the first end ii.

If the tube 5 is inserted into the drainpipe 3 too far, the helical configuration will not be maintained and the operation of the drainage device 1 may become compromised. To help prevent this from occurring a second visual indicator in the form of a radial marker is placed around the tube at a predetermined distance from the first end 11 of the tube 5. The predetermined distance reflects the length of the pipe required to form the helix measured from the distal end of the gland body. Hence, when the tube is re-inserted into the drainpipe through the gland assembly, the mark will meet the end of the gland body when the tube 5 is in the correct position.

A skilled person will appreciate that the role of the markers is to keep the tube in the correct position and any type or configuration of suitable indicator can be used to achieve this.

The drainage device 1 can be used for various applications. In Figure 6, there is shown a drainage device 1 installed on a vertical drainpipe 3 of a domestic drainage system 67. The second end of the tube 5 is coupled to a storage vessel in the form of a water butt 69. The drainage device 1 will collect the water and over time and fill the water butt 69. If the level of water within the water rises to such an extent that it reaches the overflow pipe 71 without being drained, then water will siphon back into the drainpipe 3. The skilled person will appreciate that other overflow mechanisms for water butts are known in the art and can be used with the drainage device 1.

To install the drainage device 1, a first hole and a second hole are drilled into the drainpipe 3 having the necessary vertical separation. The vertical separation of the holes will determine the dimensions of the helix formed by the tube 5. If the pitch of the helix is too great compared to the diameter of the drainpipe 3, the accurate positioning of the tube 5 will be difficult. If the pitch of the helix is too small, the flow within the tube 5 and in the trough on top of the tube will be too little and the efficiency of the tube 5 will be reduced.

To accurately position the apertures 7 relative to one another, a template is used which includes markings showing the locations of the holes. The template is made from paper and temporarily mounted on the drainpipe 3 in the correct position using sticky tape. The two holes are drilled before the template is removed. In another embodiment, the template might be plastic and have holes formed in it to provide a guide for the drill. The skilled person will appreciate that other configurations and materials for a template are possible.

After the two holes have been drilled, the tube 5 is passed into the first hole and out of the second hole. Given the spacing of the holes and the flexural rigidty of the tube 5, a guiding member can be used to thread the tube 5 into the first hole and out of the second. The guiding member is in the form of a curved needle having a hook one end. The hook is attached to a corresponding hole in the second end of the tube 5. The needle can be fed into the first hole and the curve of the needle is such that it can easily be passed in through the first hole and out of the second hole. Once fed through the interior of the drainpipe 3 and out of the second hole, the tube 5 can be threaded through accordingly. The guiding member can then be removed. The guiding member is made from plastic but can be made from other materials as will be appreciated by the skilled person.

Next, the anchor 9 is attached to the first end 11 of the tube 5 via the engaging member.

The clamp 15 is then passed over the second end of the tube 5 and taken up to the drainpipe 3 and fixed around the drainpipe 3. To fix the clamping device 13, the arms 41 are forced apart by hand until the gap separating them is large enough to accept the drainpipe 3. Once the clamping device is roughly in place, the bolt 45 can be loosely fitted through the plate members 43 before finely adjusting the position gland assembly 21 to ensure that the foot portion 39 is located in the second hole. The bolt 45 can then be tightened so that the arms 41 grip the drainpipe 3 and retain the clamping device 13 in a fixed position relative to the drainpipe 3.

After the clamping device 13 is fixed, the tube 5 is re-inserted into the gland assembly 21 with alignment marks lined up. Thus, as the tube 5 is pushed into the drainpipe 3 it is rotated to keep the apertures 7 in the correct orientation with regard to the inner surface 19 of the drainpipe 3. The tube 5 is pushed until it contacts the edge of the drainpipe. A small amount of further pressure ensures a good contact between the inner surface 19 of the drainpipe 3 and the tube 5 which helps reduce the gap between the inner surface 19 and the tube 5, particularly by the second hole. However, if too much excess pressure is applied the tube 5 will veer off the coaxial path 48 defined by the clamping device 13 and anchor 9. If this occurs, the continuous downward trajectory of the tube 5 may not be maintained and the drainage device 1 may cease to work. Hence, if the radial marker passes the entrance of the gland the tube 5 should be removed and re-inserted.

Once the drainage device has been installed, the second end of the tube 5 can be inserted into the water butt 69.

Claims

CLAIMS: 1. A drainage device for draining liquid from a drainpipe comprising: a conduit having a first end and a second end for channelling liquid from the drainpipe including at least one inlet between the first and second ends for receiving the liquid to be channelled; an anchor having an attaching portion for attaching the anchor to the drainpipe and a coupling portion for coupling to the first end of the conduit; and a clamping device having at least one formation for attaching the clamping device to the pipe and a clamp for clamping the conduit between the first and second end.
2. A drainage device as claimed in claim 1 in which the conduit is a tube in which the inlet includes an aperture.
3. A drainage device as claimed in claim 2 having a plurality of apertures positioned along a longitudinal axis which radially traverses the tube wall along the length of the axis so that when the tube is formed into a helix of predetermined dimensions about an axis the apertures are oriented in a common direction relative to the axis.
4. A drainage device as claimed in claim 3 in which the tube includes a first visual indicator to show the position of the longitudinal axis along which the apertures are located.
5. A drainage device as claimed in either of claims 3 and 4 in which the tube includes a second visual indicator at a predetermined length from the first end of the tube.
6. A drainage device as claimed in any preceding claim in which the formation for attaching the clamping device is a flexible member which at least partially encircles and grips the drainpipe.
7. A drainage device as claimed in claim 1 in which the clamping device includes a gland assembly to provide the clamp.
8. A drainage device as claimed in any preceding claim in which the drainpipe has a circular cross-section and the clamping device is arranged so as to define a passageway for the tube which is tangential to the cross-section of the drainpipe.
9. A drainage device as claimed in any preceding claim in which the coupling portion comprises a member having a longitudinal axis to which the first end of the tube can be attached; and, the anchor and clamping device are configured so that when located in a drainpipe 10. in predetermined positions relative to each other the longitudinal axis of the coupling portion member and a longitudinal axis of the passage in the clamping device are coaxial around the inner surface of the drainpipe so as to define a helical pathway the for the tube to be located on.
10. A drainage system comprising: a substantially vertical drainpipe; and, the drainage device of any of claims 1 to 9 arranged so that the tube has a helical configuration within the drainpipe.
11. A drainage system comprising: a substantially vertical drainpipe having an inlet for receiving liquid, an outlet and a longitudinal axis, which includes a first hole and a second hole in which the first hole is positioned closer to the inlet than the second hole with respect to the longitudinal axis of the drainpipe; an anchor attached to the first hole and having the first end of a conduit attached thereto inside the drainpipe; a clamping device attached to the drainpipe having a clamp proximate to the second hole through which the conduit passes and is clamped, in which the tube has a substantially helical configuration between the anchor and the clamping device with an outer wall of the tube in contact with the inner surface of the drainpipe, the conduit including at least one inlet arranged so as to receive liquid from the inner surface of the drainpipe such that the liquid is channelled to a second end of the conduit located outside of the drainpipe.
12. A drainage system as claimed in claim 8 further comprising a storage vessel in fluid communication with the second end of the conduit.
13. A kit of parts comprising the drainage device according to any of claims ito 9.
14. A kit of parts as recited in claim 13 further comprising a needle having a formation at one end for attaching to an end of the conduit.
15. A kit of parts as recited in claims 13 or 14 further comprising a drill template for placing on the drainpipe and having predetermined marks suitable for indicating the relative position of two bore holes.
16. A kit of parts as recited in any of claims 13 to 15 further comprise at least one bung for sealably inserting into a hole in the drainpipe.
17. A method of installing a conduit in a drainpipe for channelling water to the outside of the drainpipe via the conduit in which the drainpipe is in a substantially vertical position, the method comprising the steps of: boring a first hole in the pipe; boring a second hole in the pipe at a position vertically lower than the first hole; attaching an anchor to the first end of the conduit; passing the second end of the conduit into the first hole and out of the second hole; attaching the anchor to the drainpipe such that the first end of the drainpipe is fixed relative to the pipe; passing the second end of the tube through the clamp of a clamping device and attaching the clamping device to the drainpipe so that the clamp is proximate to the second hole; feeding the conduit back into the second hole so that the inner surface of the drainpipe and an outside surface of the conduit come into contact; and clamping the conduit with the clamp so as to retain the conduit within the drainpipe in contact with the inner surface.
18. A method as recited in claim 17 fUrther comprising putting the second end of the conduit in to a collection vessel for collecting and storing liquid collected from the drainpipe.