EP0920923B1

EP0920923B1 - Cleaning apparatus

Info

Publication number: EP0920923B1
Application number: EP19980309951
Authority: EP
Inventors: Leslie John Dainton
Original assignee: Heathrow Hydrant Operating Co Ltd
Current assignee: Heathrow Hydrant Operating Co Ltd
Priority date: 1997-12-08
Filing date: 1998-12-04
Publication date: 2003-09-10
Anticipated expiration: 2018-12-04
Also published as: GB2332032A; DE69817983T2; DE69817983D1; GB2332032B; EP0920923A2; EP0920923A3; GB9725948D0

Description

The invention relates to pipeline cleaning sledges and in particular sledges for cleaning airport fuel hydrants.
Aviation fuel hydrants are a pumped system with a network of underground pipes to convey aviation fuel at the required quality to aircraft stands. Inspection of the internals of the pipe work using conventional pipeline inspection and cleaning pigs is normally impossible due to features such as low point drains, valves and the general design of the hydrant system. Hence internal inspection and the removal of contaminants is extremely difficult. As an example of the constructional features present in fuel hydrant pipelines are 26 mm (1 inch) pipes that pass vertically across the diameter of the pipeline every 500 metres.
The cleaning of fuel hydrant systems has been difficult the only methods known at present are fast flushing the system with product or, alternatively, removing the pipework from service and dismantling to provide sections of pipe through which a pig can be pushed. This latter method is often impracticable. It is not yet known to provide a cleaning 'pig' which can be used in a fuel hydrant system whilst the aviation fuel remains in the system.
Most fuel hydrant systems will not accept known 'intelligent' pigs because the hydrant systems are provided at intervals with sumps where, for example, water, settles out. The systems also have tight bends compared with the pipelines built to accept known 'pigs'. 'Pigs' are designed generally to fit the entire diameter of the pipe on which they are to be used, however, fuel hydrant systems have very large pipes, typically 461, 512, 614 mm (18, 20 and 24 inch). These large pipes are generally located below ground with access through the fuel outlets which are small vertical risers of much smaller diameter than the main hydrant pipe, typically only 100 to 150 mm (4 to 6 inches).
A prior art pipeline pig for use in oil pipelines and the like, is disclosed in GB-A- 2091838, having magnetic pole pieces mounted onto a body of a pig adjacent driver cups and either side of cleaning brushes. The driver cups are substantially the full diameter of the pipeline so that the pig is driven by the force of product within the pipeline forcing against the flexible cups. The pig described is designed to enter the pipeline at full diameter to which end a 'launch trap' is added to the pig for effecting entry into a pipeline. The pigs described are not, therefore, suitable for use in a pipeline such as the fuel hydrant described above as they are not able either to enter, or traverse, such pipelines which cannot be entered at full diameter and are not designed for pigs.
In GB-A-2147970, a cleaning apparatus is described and a method for removing debris from concealed ducts. One end of a hose is introduced into the duct, the end of the hose being attached to a crushing device which acts upon large pieces to reduce them to a size that reduced pressure within the hose will draw the debris along the hose to an external discharge station. The device is particularly intended for use in sewers; the crushing device allowing bricks and the like to be removed from sewers. This apparatus, instead of, or in addition to a crushing device may have means for loosening matter from the walls of the duct being cleaned; such means includes a vibration device, a fluid entrainment device or a water jet device. The cleaning apparatus may have skids facilitating movement through the duct and means for steering the apparatus through the duct. The apparatus may be pulled through the duct, for example, by means of a winch attached to the apparatus by a cable. This document also discloses the use of a video camera, or the like, supported on a body of the apparatus.
It is not, therefore, known to use a 'pig' or similar cleaning apparatus in an aviation fuel hydrant due mainly to the architecture of such hydrants.
It is an object of the invention, to provide cleaning apparatus for a pipeline which can enter through natural features such as risers having a smaller diameter than the main pipeline. It is also an object of the present invention to provide apparatus for effectively cleaning a pipeline. It is a further object of the present invention to allow cleaning of pipelines such as fuel hydrants without taking the hydrants out of service or draining the fuel. Such apparatus allows a cleaning operation to take place in the five hour overnight period when the hydrant is not in use. It is yet another object of the invention to provide pipeline cleaning apparatus which can be used in pipelines containing product, such as fuel, without contaminating the product
US-A- 5461746 discloses a cleaning apparatus having at least one magnet supported by a support member.
JP-A-04115039 and DE-A- 3440432 each disclose cleaning apparatus adapted for use in a pipeline or hydrant system containing product without first removing product from the pipeline or hydrant, the apparatus comprising a support member, a suction means supported by the support member for removing at least impurities from the pipeline or hydrant system as the apparatus is moved therethough, the suction means comprising an inlet in the form of a suction foot having an inlet opening and a conduit extending from said inlet opening, a distal end of said conduit being connectable to vacuum means for sucking at least impurities via said inlet opening into the conduit for removal of said impurities, wherein the suction foot is configured so that a low pressure area is created beneath the suction foot between the suction foot and a surface of a pipeline within which the apparatus is being used.
The invention is characterised in that at least one magnet (3) is supported by the support member (1) and the position of said at least one magnet (3) is adjustable so that, in use, the distance between the or each magnet and the pipe wall may be varied.
The apparatus is adapted to be introduced into the pipeline or hydrant through features of the pipeline or hydrant having a smaller cross-section than a main pipeline or hydrant portion. The apparatus can be used in pipelines or hydrant systems not designed to be cleaned by conventional pigs.
Preferably the cleaning apparatus is sized so as to be introduced into the pipeline or hydrant via features of the pipeline or hydrant having a smaller diameter than the hydrant itself.
It has not previously been possible to use 'pigs' and the like in, for example, aviation fuel hydrants having intricate design and architecture. The apparatus of the invention is particularly useful in fuel hydrant systems such as aviation fuel hydrants. The materials of the cleaning apparatus are such as not to contaminate the product in the pipeline or hydrant system. As a consequence of the requirement to maintain the quality of the fuel, yellow metals (e.g. zinc, brass, bronzes, copper) may not be used in the cleaning apparatus. Preferred metals are steel and aluminium, other materials which may be used are nylon and other fuel-compatible rubbers or plastics materials.
The support member may comprise the deck of a sledge. The sledge may comprise runners depending from the deck in conventional manner. The runners may be provided with wheels or tracks. The sledge may have steering means and where the sledge runners are wheeled, the wheels at at least one end may be steerable.
Any convenient means may be used to move the apparatus through the pipeline or hydrant system. In a preferred embodiment draw wires are attached to at least one end of the sledge for pulling the sledge through the pipeline or hydrant system. Alternatively or in addition, a stiff wire may be used to push the sledge.
Preferably, the magnetic field producing means comprises a plurality of U-shaped magnets.
The suction foot is configured so that a low pressure area is created beneath the suction foot between the suction foot and a surface of a pipeline within which the apparatus is being used, whereby a force is produced on the apparatus in the direction of said surface. In this manner the stability of the apparatus is greatly increased.
It is a preferred feature of the invention that the combination of the force produced on the apparatus by the suction foot and the force produced by the magnets on the apparatus towards the surface of a pipeline allow the apparatus to traverse the pipeline around the circumference thereof. The apparatus may be designed to be as small and light as possible to assist this feature.
The conduit may comprise a passageway extending from the inlet opening through the suction foot to an aperture in a wall thereof and a suction hose operatively attached to said suction foot via said aperture to communicate with said passageway.
The invention will now be described in more detail and by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of cleaning apparatus in accordance with the invention;
Figure 2 is a schematic diagram of the apparatus in use in a hydrant pipeline;
Figure 3 is a side view of the sledge of the apparatus shown in figure 1;
Figure 4 is a rear view of the apparatus shown in figure 1 and showing a suction foot partially in cross-section taken along the line A-A in figure 6;
Figure 5 is an underneath view of the suction foot; and
Figure 6 is a side view of the suction foot partially in cross-section taken along line B-B in figure 4.

Referring now to figure 1, a cleaning apparatus in the form of a sledge is shown which is of a size suitable for introduction into, for example, a fuel hydrant system, by way of hydrant pit valve risers.
The sledge 10 has a support member or deck plate 1 supported on two runners 2 to allow ease of running along the hydrant pipe. The deck plate 1 has five magnets 3 secured below its lower surface at a forward portion thereof by any convenient means, for example, the deck plate 1 may be provided with mounting holes and the magnets 3 with threaded bores for receiving bolts (not shown). Besides mounting holes, the deck may be provided with guide wire holes 6 for attaching guide wires (not shown) to either end of the sledge.
A suction foot 4 is also secured underneath the deck plate 1 at a rear portion thereof; rear being defined in terms of the normal direction of motion of the sledge 10 during the cleaning operation. Cleaning can take place, however, when the sledge is moving in any direction. The suction foot 4 will be described in more detail below with reference to figure 4 of the drawings. Generally, the suction foot 4 is constructed with a lower edge conforming to the radius of a pipeline in which the apparatus is to be used. The suction foot 4 is connected to a suction hose conveniently by a swivel joint 5 to allow free rotation of the hose. The reinforced hose 7 is passed out of the pipeline via a riser to a filter, a pump which provides the suction and to a tanker for storing the
matter removed from the pipeline. The clean fuel being returned to the storage tanks following quality control checks.
The cleaning apparatus of the present embodiment is intended for use in aviation fuel hydrants. The sledge 10 is small enough that it can enter the hydrant system via existing features, such as hydrant pit valve risers. The hydrant remains full of fuel. For this reason and to prevent contamination of the fuel by introduction of the apparatus, all parts of the apparatus entering the hydrant system are made of inert materials compatible with fuels. The sledge 10 may be of steel and/or aluminium, and the hose 7 and other fittings may be of fuel compatible rubbers or plastics.
The sledge 10 is manoeuvred for example, by using draw wires secured to each end of the sledge using guide wire holes 6. The draw wires may be made of nylon ropes or cables, for example. The progress of the sledge can be monitored using a CCTV camera. Arrows A in Figures 1 and 2 show the direction of travel of the apparatus during the cleaning operation.
Figure 2 shows the apparatus in use in an aviation fuel hydrant pipeline 8. The sledge 10 is used by traversing between the pit risers 9. The main pipeline 8 is typically 461 mm (18 inches) in diameter and the risers 9 are typically 154 mm (6 inches) in diameter. The risers 9 open out to hydrant pit boxes 9a which extend to the surface of the apron.
A draw wire 11 is inserted into the hydrant down a pit riser 9 along the length to be worked on. The draw wire 11 is then secured to both ends of the sledge 10. In this way the sledge 10 can be retrieved via either riser 9, cleaned and reinserted. As the sledge 10 moves between the risers 9, the magnets 3 attract any magnetic particles and thereby loosen debris and sediment which may have accumulated at the bottom of the pipeline 8.
A suction hose 7 attached to the suction foot 4 at one end is connected via a coarse filter to a self priming suction pump and then a tanker. The filter, pump and tanker may take any conventional form and are not shown in the drawings. The length of the hose 7 is limited by the performance of the pump and the pressure required at the suction foot.
The activity of the cleaning apparatus can be monitored throughout the cleaning operation by a CCTV camera 12. The camera 12 may take any conventional form, but shall comply with the correct electrical classification for the pipeline product, for example for fuel hydrants the camera will be explosion proof. The camera 12 and a separate or integral light unit are inserted at the same time as the sledge 10. The camera 12 has its own supply cable 13 but may be linked to the sledge by a cable or rope for the purposes of movement. In this embodiment the camera follows behind the sledge 10 at a distance of about one foot, but may be located on the sledge 10 if size parameters permit.
In an alternative embodiment, the sledge may be moved by means of a stiff wire rather than a draw wire 11. In this way, the sledge 10 can be manoeuvred into dead ends by pushing the sled into position. Both means may be available for use with the same sledge 10.
Referring now to figure 3, a side view of the sledge 10 is shown, before the magnets 3 and suction foot 4 are attached. A heavy deck plate 1 provides good mass for stability and a structurally stiff base for supporting the magnets 3, the suction foot 4 and any other features. The sledge runners 2 are attached to the deck plate 1 by four leg members 14 which depend from the deck plate 1 at an angle for increased stability. The sledge runners 2 are curved at each end so as to ease hydrant entry and the passage of the sledge 1 through any sediment. The deck plate 1, runners 2 and legs 14 are conveniently, welded together. In an alternative embodiment, the sledge runners 2 may be provided with wheels or replaced by caterpillar tracks and the like.
In figure 4, a rear view of the suction foot is shown partially in cross-section. The suction foot 4 may be suspended or fixed to the deck plate 1 by any convenient means and is preferably adjustable so that the distance between the lower peripheral edge 15 of the suction foot 4 and the:pipeline surface may be varied. The top of the suction foot may be provided with mounting holes so that the suction foot can be bolted to the deck plate 1. The bolts may also be used to adjust the distance between the peripheral edge 15 and the interior wall of the pipeline. Advantageously, the peripheral edge 15 of the suction foot has a radius which is concentric with the periphery of the pipeline when in use.
An aperture 16 in an upper portion of the rear wall 17 of the suction foot 4 allows connection of a hose via a swivel joint. An inlet opening 18 in the lower surface of the suction foot 4 permits entry of product from the pipeline. As shown in figure 5 the opening 18 is a rectangle having rounded ends cut out of the bottom face of the suction foot. As shown in figure 6 the inlet opening 18 communicates with the aperture 16 via a passageway 19 for passage of matter through the foot to the hose 7. The suction foot 4 has a profile designed to produce a low pressure area beneath the foot over substantially the whole of the width of the sledge 10. A high velocity of product is generated around the sides of the suction foot 4. The moving product carries debris, sediment and other matter into the centre of the suction foot 4, up to the aperture 16 and into the hose 7.
The suction foot 4 of the embodiment also provides a significant radial force (downward pressure) on the sledge 10 due to the low pressure area underneath the foot 4. There is a corresponding increase in the radial load (down force) on the runners 2. In this way the directional stability of the sledge is improved; there is also an improvement in the efficiency as the sledge is pushed/ pulled forwards and backwards along the pipeline. The downward force prevents the sledge 10 from riding up on top of the debris or particulate matter; instead it cuts through such matter.
The magnets 3 on a forward portion of the deck 3 function, as in the prior art, to generate a magnetic field across the sledge which lifts any ferrous material from the surface of the pipe. The magnets may be simple U-shaped magnets spaced from the pipeline surface so as to optimise debris pick up.
The magnets 3, may also provide an additional downward force (radial load) on the runners 2 which help to stabilise the sledge. The amount of down force may be varied by adjusting the clearance between the magnets 3 and the internal surface of the pipeline. This downward force is balanced with that produced by the suction foot to provide optimum performance. The adjustment can be effected by means of the securing bolts, but any convenient method may be used.
It is a particular feature of the present invention that the downward force produced by the suction foot 4, optionally combined with a downward force produced by the magnets 3 may be sufficient to overcome the force of gravity so that the radial position of the sledge on the internal surface of a pipeline may be varied. Taken to its conclusion, if the sledge is light enough the combined force of the suction and the magnetic field in the direction of the internal surface of the pipeline may allow the sledge to be inverted, i.e. rotated 180 degrees around the pipeline. In such an embodiment of the invention, the sledge is preferably provided with some steering means. In any case, the sledge is then able to navigate past constructional features in the central plane of the pipeline.
In the case where the sledge is adapted to maintain itself at different radial positions around the pipeline by virtue of the downward forces produced by the suction foot 4 and the magnets 3, it is preferable that the swivel connection 5 for the hose 7, allows sufficient rotation, typically unlimited, so that there is no twisting action of the hose imparting a role over torque on the sledge. A glass fibre drive rod is also connected to the sledge with a swivel joint providing 180 degrees horizontal and 180 degrees vertical swivel.
Whilst an embodiment of the invention has been described, variations and modifications will suggest themselves to those skilled in the art which do not depart from the scope of the invention as defined in the appended claims.

Claims

A cleaning apparatus adapted for use in a pipeline or hydrant system containing product without first removing product from the pipeline or hydrant, the apparatus comprising
a support member (1);
a suction means (4) supported by the support member for removing at least impurities from the pipeline or hydrant system as the apparatus is moved therethough, the suction means (4) comprising an inlet in the form of a suction foot (4) having an inlet opening (18) and a conduit (19) extending from said inlet opening, a distal end of said conduit being connectable to vacuum means for sucking at least impurities via said inlet opening (18) into the conduit for removal of said impurities, wherein the suction foot (4) is configured so that a low pressure area is created beneath the suction foot between the suction foot and a surface of a pipeline within which the apparatus is being used;
characterised in that at least one magnet (3) is supported by the support member (1) and the position of said at least one magnet (3) is adjustable so that, in use, the distance between the or each magnet and the pipe wall may be varied
Apparatus as claimed in claim 1 wherein, the materials of the cleaning apparatus are such as not to contaminate the product in the pipeline or hydrant system.
Apparatus as claimed in claim 1 or 2, wherein the apparatus comprises a sledge (10) and the support member comprises the deck (1) of a sledge,
Apparatus as claimed in claim 3, wherein the sledge is provided with wheels and at least one set of wheels is independently steerable.
Apparatus as claimed in any one preceding claim and further comprising means for moving the sledge through the pipeline or hydrant system.