GB2147970A - Removing debris from ducts - Google Patents

Abstract

There is disclosed a method of removing debris from concealed ducts. One end of a hose 58 is introduced into the duct, the end of the hose being attached to a crushing device which acts upon any large pieces to reduce them to a size where reduced pressure within the hose will draw the debris and crushed debris along the hose to a discharge station externally of the duct. The crushing device 50 includes at least one jaw member 113 which is reciprocated by power means, preferably a hydraulic actuator 100. The jaw member 113 may co-operate with a stationary jaw member 115. <IMAGE>

Description

SPECIFICATION Method and apparatus for removing debris from concealed ducts This invention relates to a method of and apparatus for removing debris from concealed ducts, which term is intended to include any duct to which access cannot readily be gained along the entire length thereof for maintenance purposes. The invention is particularly, but not exclusively, pertinent to a method and apparatus for removing debris from subterranean sewers which are used to convey waste water, although the invention has many other applications for example in removing debris from pipes which normally convey fluids such as water or gas.

In use, subterranean sewers become clogged with debris which may be conveyed into the sewer through an entry such as a roadside gulley or other entry. Additionally where the sewer is made from bricks, the bricks may in time become dislodged, for example by tree roots growing into the sewers. In each case, the debris usually accumulates at a low part of the sewer and presents significant problems in removal. It is usual practice to urge the debris along the sewer to a location from where it may be removed, such as a manhole opening, but such methods are slow, unreliable and difficult.

An alternative method would be to remove the debris by differential pressure, i.e. introducing a vacuum hose and drawing the debris into and along the hose to a discharge station which may conveniently be located above the ground. However, large pieces of debris such as bricks are not readily removed by this method due to their weight, shape and size, although for the removal of smaller pieces of debris the differential pressure method is very efficient.

Accordingly, it is an object of the present invention to provide a new or improved method and apparatus for removing debris from concealed ducts.

According to one aspect of the present invention, we provide a method of removing debris from concealed ducts including the steps of introducing one end of a hose into the duct, the end of the hose having attached thereto a crushing device, acting upon any large pieces (as herein defined) of the debris by the crushing device to reduce the size of the large pieces of the debris, reducing the pressure within the hose, passing the crushed debris from the crushing device into the hose, drawing the debris along the hose to a discharge station externally of the duct at which the debris is discharged from the hose.

According to a second aspect of the invention, we provide an apparatus for removing debris from concealed ducts, comprising a crushing device including at least one jaw member which is reciprocated by power means along a predetermined path to act upon any large pieces (as herein defined) of the debris to crush and hence reduce the size of the large pieces of debris, a hose attached to the crushing device, and means to reduce the pressure within the hose to draw the debris into an opening in, and along, the hose to a discharge station externally of the duct.

The expression "large pieces" should be taken to mean any piece of debris which is too large to be easily removed from the duct solely by the reduced pressure within the hose. Typically such pieces have a minimum dimension of at least 5.5cm.

Hence the debris within the duct can be simply and easily removed. There is no necessity to move the large pieces of debris along the duct as these are crushed in the crushing device. Of course, other debris which would not require crushing would be removed by the hose along with the crushed debris.

The end of the hose and the crushing device (hereinafter referred to jointly as "the hose head") may conveniently be moved along the duct to the debris by hauling, using a cable and winch means. The winch is preferably located adjacent an opening of the duct which, where the duct is a subterranean sewer, may be a manhole opening, and the cable may pass into the duct from that opening and be connected to the hose head, i.e.

the hose and/or the crushing device.

If required, a further cable may be attached to the hose head for the purpose of retracting the hose head back along the duct after the debris therein has been removed. Alternatively, instead of cables, the hose head may be provided with its own motive means, such as water jets, to propel the hose head. In any case, conveniently, the crushing device is mounted on a carriage which may be provided with skids to facilitate movement of the hose head along the inside of the duct.

The debris to be removed may be located using a closed circuit television camera mounted at the hose head. The position of the camera may be arranged to be adjustable remotely so that all parts of the sewer can be examined. Alternatively, an X-ray, ultrasonic or other detector could be provided. Where a television camera is used, a light source may also be provided to illuminate the interior of the duct. There may be provided means to keep clean the Lens of the camera and, where provided, the light source. It may be one or more air flows across the face of the lens or light source, preferably a radial inflow of air from an annular gap around the lens or light source. The air flowing radially inwardly meets in the region of the lens centre and flows axially forwardly to divert particles which might otherwise hit and obscure the lens.

The jaws may undergo a pliers-like action to crush the debris. Alternatively, the crushing device could comprise relatively rotatable members which subject the debris to a crushing action.

Preferably, said at least one jaw member is reciprocated in an arcuate path about a pivot axis, although any other reciprocating movement may be used. The jaw member may be rigidly secured, or be integral with a cylindrical member, hereinafter called a drum, which can be solid or partially or completely hollow, and rotates about the pivot axis, the jaw member extending from the surface of the drum. The jaw member may be provided with a hardened steel tip for long life.

In a preferred embodiment, a plurality of jaw members are provided to provide an array across substantially the entire width of an opening in the crushing device through which the debris is drawn. The jaw members may all extend from said drum and mmay thus all be rotatable about a common axis, which is preferably horizontal although could be in any other orientation.

The reciprocable jaw member or members may co-operate with a stationary jaw member or stationary jaw members to crush the debris therebetween.

Preferably, the power means for causing said reciprocation is one or more hydraulic actuators attached to the or each jaw member by a link. For example, where the or each jaw member projects from a drum, the drum may have a further projection spaced from the jaw member or members around the periphery thereof, to which the link connected to the hydraulic actuator is pivotally connected, so that reciprocating movement created by the actuator is converted into an arcuate movement of the drum, in a crank-like arrangement.

The hydraulic actuator or actuators is/are preferably remotely controllable externally of the duct.

Alternatively, any other means such as pneumatic means or electric means could be provided to cause said reciprocation of the or each jaw member. The rate of reciprocation and the characteristic thereof, i.e. whether the jaw is reciprocated at equal speeds in both directions or faster in a first direction at the end of which movement the jaw member contacts the debris, than in a second direction when the jaw member moves away from the debris will be governed by a control gear, such as a hydraulic valve where the jaw member is hydraulically powered.

The reduced pressure in the hose may only be established after the debris has been acted upon by the crushing device, although more conveniently, the reduced pressure is permanently established so that debris (both large pieces after crushing and uncrushed smaller pieces) is continually drawn into the hose and removed from the duct.

The discharge station may comprise a collector for the removed debris, such as a closed container, in which a reduced pressure is established by pumps such as cyclone pumps. Such an arrangement is disclosed in European Patent Application No. 81303562.

The hose may be readily detachable from the container so that when the container is filled, the hose may easily be secured to another similar container without long interruption of the process. The container may comprise a "skip" and thus be readily transportable via a lorry.

The hose head may have secured thereto a water jet cleaning head to which water under pressure may be fed from a water pump, and jetted therefrom for the purpose qf cleaning the interior of the duct.

The invention is particularly applicable to removing debris from subterranean sewers, in which case conveniently, the discharge station and other ancillary equipment such as a television monitoring screen. water pumps fluid pressure source for the crushing device etc., may be located above ground.

Any water removed from the sewer along with the debris, may be passed from the discharge station back into the sewer.

According to a third aspect of the invention, we provide an apparatus for removing debris from concealed ducts comprising a hose, means to reduce the pressure within the hose to draw the debris into an opening in, and along, the hose to a discharge station externally of the duct, means to urge the debris into said opening, said means comprising a chute, at least part of the periphery of which is in contact with or lies closely adjacent to the inside wall of the duct, means being provided to vibrate, e.g. reciprocate, the chute.

Thus any debris which is compressed or adhered to the inside wall of the duct is loosened by the periphery of the chute and hence encouraged to enter the opening in the hose.

Preferably the vibration imparted to the chute is a reciprocating movement along a direction generally longitudinally of the duct, as this has been found to give the most satisfactory results. The periphery of the chute may have a bottom forward edge which scrapes the bottom inside surface of the duct, and forward side edges which scrape part of the sides of the inside surface of the duct, and the top of the chute is preferably open. The inside of the chute may be shaped to dissuade any large pieces of debris, such as a complete brick, from jamming therein.

The bottom inside surface of the chute may be ridged to further encourage debris to move towards the opening of the hose. Preferably, the opening of the hose is in the end thereof which faces generally in the direction of the duct towards the chute.

The vibrating means of the chute is preferably pneumatically powered. for example, where the chute is reciprocated, one or more pneumatic actuators may reciprocate the chute. The chute may be positively moved in both directions of reciprocation by pneumatic actuators, although alternatively and preferably, the chute may be urged forwards or backwards by the pneumatic or other power means, and be urged backwards or forwards respectively, be resilient means such as a spring or springs.

The apparatus of the third aspect of the invention may comprise part of an apparatus according to the second aspect.

Preferably the hose head has an aperture communicating with the opening of the hose and the extent of the opening of the aperture is variable by visor means.

Thus the linear velocity of debris through the aperture, provided by the reduced pressure within the hose, can be varied, so that particularly stubborn debris can be subjected to greater suction by closing the aperture slightly. Further, where there is a large amount of debris to be removed, the maximum extent of opening can be arranged to permit greater quantities of debris to pass into the hose.

Preferably the visor means is movable about a pivot axis in an arcuate path between a fully open position where the opening is open to its maximum extent and a fully closed position where the opening is opened to a minimum extent or closed.

The visor means may be pre-set to a selected position externally of the duct before introduction of the apparatus into the duct, or preferably may be operated by hydraulic, pneumatic or other power means such as electrical power means, under remote control so that the extent of the aperture can be varied in use.

The hose head preferably provides a generally airtight communication between the aperture and the opening in the hose.

The visor may be incorporated into an apparatus according to the second or third aspects of the invention.

According to a fourth aspect of the invention, we provide an apparatus for removing debris from concealed ducts comprising a hose head, a hose attached to the hose head, the hose head having an aperture, the hose head providing a generally airtight communication between the aperture and an opening in the hose, means to reduce the pressure within the hose to draw debris into the opening in, and along, the hose to a discharge station externally of the duct, there being a chamber between the aperture and the hose head and the opening of the hose through which the debris is drawn, said chamber having means to feed fluid generally parallel to the direction of movement of the debris, into the chamber.

It has been found that in such an arrangement, the debris is more easily drawn into the opening in the hose from the hose head with a reduced risk of a blockage occurring. Preferably the fluid is gas such as compressed air, or the fluid could be liquid such as water or a mixture of gas and water. This aspect of the invention is particularlv important where, for example, the interior of the hose head is of one cross-sectional shape, e.g. rectangular, and the opening of the hose is another crosssectional shape, e.g. round.

The hose may be connected to said chamber by means of a sleeve which extends inside the hose and inside a spigot of the chamber, an O-ring or other sealing means providing sealing between the sleeve and the spigot, and if desired bearing means being provided to permit of rotational movement of the hose relative to the chamber.

Such a sealed connection prevents the leakage of air into the hose thus maximising the suction effect of the reduced pressure within the hose.

The invention according to the fourth aspect of the invention is preferably included in an apparatus according to the second and/or third aspects of the invention.

In each of the apparatus according to any aspect of the invention described above, preferably a T.V. camera and illuminating means is provided so that an observer located externally of the duct may view the operation being carried out inside the duct.

Further, the apparatus may be provided with skids or other guide means to facilitate movement of the apparatus along the duct.

The apparatus is preferably, in use, pulled along a duct by a hauling means such as a winch attached to the apparatus by a cable, although any other propulsion means may be provided.

If required, means may be provided whereby the apparatus can be steered along the duct.

The apparatus may also be provided with a water jetting head having nozzles to direct water at high pressure onto the inside walls of the duct ahead of the apparatus so that debris is loosened and hence more easily passes into the opening of the hose.

Preferably the spray head comprises a nozzle head transverse to the direction of the duct, the head having a plurality of nozzles comprising openings in the nozzle head through which the water is jetted.

It will be appreciated that apart from the suction hose, hydraulic hoses are required to provide hydraulic fluid to the crushing device, where provided and that pneumatic hoses are required for operation of the chute where pneumatically operated and, where appropriate, hoses to provide fluid for the visor, are required as well as an electrical cable for the T.V. camera and illumination means. These hoses/cable each provide an umbilical cord from the apparatus to a control location external of the duct. These umbilicals may be contained within a single covering or may be bound together or otherwise provided.It is envisaged that to reduce the number of umbilicals, electrically operated valves may be provided on the apparatus so that only one hydraulic and pneumatic hose is required for operation of all hydraulic and pneumatic actuators of the apparatus, along with the suction hose and electrical cable.

Embodiments of the invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of an apparatus for use in removing debris from concealed ducts; Figure 2 is a plan view of one example of a crusher device which may be used in the apparatus of figure 1; Figure 3 is a perspective view of another embodiment of apparatus; and Figure 4 is a cross-sectional view of the apparatus of Figure 3, with various parts omitted for clarity.

Referring to Figure 1 of the drawings, there is shown a duct in the form of a subterranean sewer 10 in which debris has accumulated.

The debris is either fed into the sewer through roadside gully openings or other entries, or the debris may comprise the material from which the sewer is made, e.g. bricks.

A plurality of manhole openings, two of which are shown at 12a, 12b, are provided along the length of the sewer 10 but because the sewer has a diameter d too small to permit ready access along the entire length of the sewer, (and may include bends although these are not shown in the example described) significant problems are presented in removal of the debris from the sewer 10. Of course, much of the debris is washed along the sewer 10 with waste water which the sewer carries, but large pieces of debris, such as bricks, are not washed along the sewer 10.

In accordance with the present invention, these large pieces of debris are subjected to a crushing action, and the crushed debris, the individual pieces of which are sufficiently small, are easily and simply removed from the sewer 10.

To achieve this, a crushing device 1 3 is moved along the sewer 10 by a cable 14 and winch means 1 5 which are located at the leftmost, as seen in the drawing, manhole, opening 1 2a. If required, a pulley 1 6 is provided at the bottom of the manhole opening 1 2a to facilitate this.

The crushing device 1 3 is attached to one end 1 7 of a flexible hose 18 and thus, as the crushing device 1 3 is moved along the sewer 10, the end 17 of the hose 18 is also dragged therealong.

It can be seen, that attached to the crushing device 1 3 is a further cable 23 which extends from the crushing device 1 3 to a further manhole opening (not shown) upstream from manhole openings 1 2a and 12b.

A further winch means is provided at this further manhole opening and the purpose of this is to enable the crushing device 1 3 and hose end 1 7 to be readily retracted along the sewer 10 when required.

The crushing device 1 3 is conveniently provided with skids which ride on the inside 1 9 of the sewer 10 and thus help to maintain the crushing device 1 3 in an upright orientation.

However, the upright orientation of the crushing device 1 3 is assured by ,providing the device 1 3 with as low a centre of gravity as possible.

A closed circuit television camera 20 is also mounted on the crushing device 1 3 and is remotely controllable, as hereinafter described, so that the entire interior of the sewer 10 can be readily examined. A light source (not shown) is integral with the camera 20 to provide illumination.

An electrical cable 21 for the camera 20 and light source passes out of the sewer 10 along with the hose 18, through a further manhole opening 1 2b.

A further line (not shown) may be provided for passing compressed air to the device. The compressed air exits from an annular gap (not shown) surrounding the camera lens and is directed radially inwardly to keep the lens clear.

The crushing device will be described in more detail hereinafter. The device is hydraulically actuated and the hydraulic power line 22 therefor is fed to the crushing device 1 3, again through the manhole opening 12b.

The hose 18, hydraulic power line 22 and electrical cable 21 for the television camera 20 and light source, each extend above the ground and follow a generally common path.

If required, the line 22 and cable 21 may be located inside the hose 1 8.

The other end 24 of hose 1 8 is detachably connected to a skip 25 in which a reduced pressure may easily be established by a vacuum pump 26 or pumps, e.g. cyclone pumps which are powered by a compressor 27. Thus a reduced pressure will be established in the hose 1 8 so that the debris can be drawn into and along the hose 1 8 and discharged therefrom into the skip 25 above ground.

The skip 25 is readily transportable on a lorry or the like and thus the discharged debris can be easily transported to a dumping site.

The connection between the hose 18 and the skip 25 is readily detachable so that when the skip 25 is filled, the hose 18 may easily be connected to a further similar skip without lengthy stoppages in the debris removal process.

The hydraulic power line 22 is connected to a hydraulic power pack 28 and control console and the cable 21 from the television camera 20 is connected to a closed circuit television screen and control panel 30 at which the interior of the sewer 10 can be viewed.

Optionally, provided on the crushing device 1 3 is a water jetting nozzle to which water is fed under pressure via a further hose 31 from a high pressure water pump 32 to which water is supplied from a bowser 33. The purpose of this water jetting nozzle is to clean the interior of the sewer by jetting high pressure water onto the surface thereof as the device passes therealong.

The method in accordance with the invention will now be described.

The crushing device 1 3 and end 1 7 of the hose 18, together for convenience called a hose head, is introduced into the sewer 10 and moved therealong using the winch means 1 5 and cable 14, the interior of the sewer 10 being viewed continually using the television camera 20 and screen 30.

When debris, the individual pieces of which are too large easily to pass along the hose are encountered, e.g. bricks, the pieces of debris are crushed by the crushing device 1 3. A reduced pressure is maintained in the hose 1 8 permanently and thus as the crushing device 1 3 continues to move, the crushed debris passes into the end 1 7 of the hose 1 8 and is conveyed to the discharge station, i.e. the skip 25 above ground.

Of course along with debris, water would also be withdrawn from the sewer and be discharged into the skip 25. Preferably, an overflow, such as shown at 25a, is provided from the skip 25 to enable this water to be returned to the sewer 1 0.

If desired the water jetting nozzle (where provided) may be operated simultaneously with or separately from the crushing device 1 3.

The apparatus described may be substantially modified whilst still enabling the method according to the invention to be carried out.

For example, the crushing device 1 3 need not be hydraulically powered as described, but could be pneumatically powered or electrically powered as required, in which case alternative power lines to the hydraulic line 22 would be required.

It is not essential to provide a television camera means 20 as described, but any other means such as an X-ray or ultrasonic detector could be provided to locate the debris which needs to be crushed.

Of course where an X-ray ultrasonic or other detector were used in place of television camera 20, the light source would need to be replaced by an appropriate X-ray, ultrasonic or other source.

Instead of moving the crushing device 1 3 along the sewer by a cable 1 4 and winch mechanism 15, if desired the crushing device 1 3 may be provided with its own motive means such as rear facing water jets to propel the device 1 3. If desired, more than one cable for towing the device 1 3 may be provided. to enable the device 1 3 to be "steered" towards the pieces of debris located by the detector.

In place of the skip 25, and cyclone pumps 26 etc., any other means for establishing a reduced pressure within the hose 1 8 could be used, although the apparatus described is preferred because of the advantages identified, i.e. a vacuum can easily be formed in the skip, and hence hose, and the skip can easily be replaced when full of debris, and transported from the site on the back of a lorry.

Where no water jet cleaning nozzle is provided, the water pump 32 need not be provided and nor would bowser 33 or hose 31.

However, where a nozzle is provided, instead of using a bowser 33 water may be withdrawn from the sewer 10 and passed into the pumps 32 to provide water for jetting.

Although the invention has been described with reference to removing debris from a sewer 10, of course the invention is equally applicable to removing debris from any other concealed duct, that is a duct in which ready access to the entire interior of the duct for maintenance purposes is not possible.

Referring now to Figure 2, a first example of one type of crushing device 1 3 which may be used in accordance with the invention, is shown.

The device 1 3 comprises a carriage including two skids 30 which, in use, ride on the inside of the sewer or other concealed duct, and guide the device 1 3 as well as giving stability.

The front end 31 has a body part 32 with means 33 for attaching a winch cable 14.

Pivoted on the body part at 34 are a pair of jaws 35 which each comprise a gripper part 36 for gripping a piece of debris, e.g. a brick to be crushed, and an inwardly extending projection 37 which, as the jaws 35 are closed around the piece of debris, act together to break and crush the debris.

The jaws 35 are each rigid with a lever 40, which levers 40 are themselves pivoted to further links 41 which are connected together as shown at 42, again in a pivotal manner.

The levers 40 cross over one another and the jaws are shown in a closed position. The pivot 42 of links 41 are connected to the movable part 43 of a hydraulic actuator 44.

Thus as the movable part 43 is moved to the left as seen in the drawings, i.e. is extended, the ends of the links 41 pivoted to the levers 40 will move further apart thereby opening the jaws 35. As the movable part 43 of actuator 44 is retracted, any piece of debris between the jaws 35 will be crushed by the projections 37 and gripped by the gripper parts 36.

At the rear end 45 of the device 1 3, a spigot 46 is provided for the hose 18, which spigot 46 terminates in an open end 47 through which crushed debris may be drawn into the hose.

Further, there is a connection 48 for the hydraulic power line 22 as well as a connector 49 for the cable 23 for withdrawing the device 1 3 along the sewer 10 or other concealed duct.

In use, with the jaws 35 open, the device 1 3 is advanced along the duct until the debris to be crushed is received between the jaws 35. The crushing action already described is then effected. If the suction of the hose is insufficient to draw the crushed pieces of debris into the hose 22, the device 1 3 is further advanced until the crushed debris is nearer opening 47 and hence the debris will be drawn into the end of the hose.

Of course, instead of being hydraulically powered, the crusher device 1 3 could be pneumatically or even electrically powered. If desired, the device 1 3 may be provided with its own motive means such as rear facing water jetting nozzles for high pressure water to propel the device 1 3 along the sewer, although any other means such as tracks or wheels could alternatively be provided.

Further, if required, instead of having to advance the device 1 3 towards the debris in order to receive the debris between the jaws 35, means may be provided to urge the debris between the jaws such as a scoop or other conveyor.

In another embodiment (not shown) the end of the hose may be suitably strengthened to enable the cables 14 and 23 to be attached to the hose rather than the crusher device 1 3.

Further the television camera 20 and water jetting nozzles described with reference to Figure 1, could be mounted on the crusher device 1 3 or on the hose end as required.

A second example of crushing device is shown in Figures 3 and 4.

The device comprises at a front end thereof, a chute 51 which encourages the debris to enter a hose head 52 which, in the present example, comprises a crushing device. At the other end 53 of the device 50, a flexible hose 58 is secured, the other end of the hose 58 extending from the duct to a remote location where means are provided to reduce the pressure in the hose 58 so that debris is drawn into the hose and along the hose to a discharge station, again located remotely of the duct.

Intermediate the hose 58 and the hose head 52 is a booster chamber 59 which is described in more detail hereinafter. The purpose of chamber 59 is to encourage the debris to pass from the hose head 52 into the hose 58 without causing a blockage.

Mounted on a casing 55 of the hose head 52 there is a television camera 60 and illuminating means (not shown). The television camera 60 and illuminating means are connected via a cable 61 to a monitoring station externally of the duct so that operations can be monitored as they are carried out.

If desired, a mirror may be mounted on the device to enable otherwise inaccessible areas to be viewed, e.g. the mouth of the chute 51 or hose head 52. A radial inflow air blast may be provided to maintain all optical parts clean, as in the preceding embodiment.

Also mounted on the casing 55 of the hose head 52 is a spray head 63 which is fed with water at high pressure e.g. 1 500 Ibs per square inch, via another hose 64 which is again connected to a suitable high pressure water supply externally of the duct.

The spray head 52 has a laterally extending nozzle head 64 provided with a plurality of nozzles 65, some of which can be seen in Figure 4, the nozzles 65 being arranged as openings in the nozzle head 64 so as to provide forwardly facing jets of water ahead of the apparatus 50 in the duct so as to loosen debris within the duct and again encourage the debris to pass into the hose 58 of the device 50.

Further, the water jets deter blockages as the thus-loosened debris passes through the device and into the hose, and the direction of water jet may be variable.

The chute 51 is mounted on two linkages 66, one either side of casing 55, each linkage 66 extending rearwardly of the apparatus 50 through three bearing mountings 67,68 and 69 and the linkages 66 are connected to limbs 102' of a common U-shaped actuating lever 70' which is reciprocated by means of a single acting pneumatic actuator 71 mounted at the rear 53 of the apparatus.

The actuator 71 has a movable rod 72 which is firmly connected to the lever 70' and the lever 70' is pivoted at pivots 73 to the linkages 66.

The chute 51 is normally biased forwardly by means of springs 77 received on internal elements 78 of the linkages 66 and act between bearing mounts 69 and external sleeves 79 of the linkages 66. The actuator 71 pulls the linkages 66 against the force of springs 77 to cause a backward movement of the chute 51 and when the air is released from the actuator 71, the chute 51 moves forward under the influence of springs 77 in a sharp movement. Thus any debris in the chute 51 is jerked rearwardly of the chute 51 towards the hose head 52. To encourage this movement, a bottom inside surface 80 of the chute 51 is provided with a plurality of ridges 81.

The periphery 82 of the chute at least adjacent the bottom surface 80 thereof, in use, engages the bottom inside surface of the duct to scrape debris from the bottom of the duct into the chute 51 as the chute amid/or the device 50 moves forwards. The forward side edges 83 of the periphery 82 again contact, or at least lie closely adjacent, the walls of the duct so as to scrape the inside walls.

A sealing means (not shown) may need to be provided between the periphery 82 and the inside wall of the duct so as to prevent debris from escaping from passing into the hose head 52 by passing around the chute 51.

It will be appreciated that for different sized and shaped ducts, different chutes 51 may need to be provided. Thus the chute 51 is made readily replacable by the loosening of screws 85 of each of the linkages 66, so that the external sleeves 79 can be slid through the bearing housings 67,68 to remove the chute 51. Any other readily releasable attachment means could alternatively be provided.

In an alternative embodiment, in place of the chute 51 being reciprocable, if desired the chute 51 may be vibrated in any other manner as required, or even fixed.

Further, although in the embodiment described, the chute 51 is reciprocated by a single acting pneumatically powered means and springs 77, if desired the chute 51 may be vibrated by a double acting pneumatic means, which causes positive movement of the chute in forward and backward directions, or by any other power means such as hydraulic or electrical power means.

Also mounted on the casing 55 are a pair of skids 90 either side of the casing 55, which skids 90 in use, engage the bottom inside wall of the duct to assist movement of the device 50 through the duct. Forward movement is effected by a winch located externally of the duct ahead of the apparatus, which is connected to the device 50 by means of a cable which is received by a cable tie 94 mounted on the top of the casing 60.

If desired a further winch tie may be provided so that rearward movement can be accomplished by a winch rearwardly of the device.

The device further comprises a double acting hydraulic actuator 100 which is described in more detail hereinafter, which is pivotally mounted to the casing intermediate limbs 101 and 102 of U-shaped frame part 70, the base 103 of the part 70 being attached to a supporting plate 104 which provides a support for the pneumatic actuator 71.

The pneumatic actuator 71 is attached to a compressed air supply by means of a hose 71' which extends from the duct.

Hydraulic hoses 105 and 106 supply hydraulic fluid under pressure to the double acting actuator 100, and these hoses 105, 106 also extend from the duct in which the device 50 is used.

Also mounted on the casing 55 for pivotal movement about an axis A thereof, is a visor 110 which can move between open and closed positions to reduce or increase the size of an aperture 111 in the hose head 52 through which the debris is drawn.

Referring now more particularly to Figure 4, a cross-section through the device 50 is shown, although many parts have been omitted for clarity. It can be seen that the hose head 52 comprises a crushing device, the casing 55 containing a drum 11 2 which is rotatable in an arcuate path about axis A. On the periphery of the drum are a plurality of jaw members 11 3 (three are visible in Figure 3) whilst further mounted on the periphery of the drum 1 12 is a lever 114.

The jaw members 11 3 are tipped with a hardened engineering steel such as Stellite or Tungsten carbide, for longer life and co-operate with fixed jaw members 11 5 mounted on the bottom of the crushing device to crush any debris received therebetween.

The lever 114 is pivotally connected via pivot 11 7 to a linkage 118, which is in turn connected to moving member 11 9 of the hydraulic actuator 1 00. Thus as the member 11 9 moves outwardly and inwardly of the actuator 100, the linkage 11 8 is caused to reciprocate and hence the drum 11 2 will be reciprocated along an arcuate path about axis A in the manner of a crank, causing the jaw members 11 3 to be first raised and then lowered with the force provided by the hydraulic actuator 1 00.

The actuator 100 is a double acting actuator requiring pressurised hydraulic fluid both to extend the member 11 9 and to retract member 11 9. Hydraulic fluid to extend the member 11 9 is provided by hose 106 whilst hydraulic fluid under pressure to retract the member 11 9 is provided by a hose 105 herein before described.

The actuator 100 is mounted via pivot 1 20 to the U-shaped frame part 70. Thus as debris enters the aperture 111 provided in the hose head 52, and is received between the reciprocating jaw members 11 3 and the stationary jaw members 11 5. the debris will be crushed before passing further rearwardly into the suction hose 58.

The visor 110 is shown in Figure 4 in a nearly closed position, closing the aperture 111 so as to provide only a restricted opening into the hose 58 for debris between the bottom of the crusher device and the lower periphery of the visor 110 and so suction produced as hereinafter described will be enhanced by the venturi effect so that even stubborn debris will be drawn into the hose 58.

The casing 55 provides an extension 125 which extends rearwardly therefrom said extension comprising a hollow tube, and on the end of the tube 1 25 is a permanently mounted, booster chamber 59. The booster chamber 59 is also a hollow chamber of larger diameter than tube 1 25 and having a number of nozzles 126' (only two of which are shown) for the introduction of compressed air into the chamber 59 in the direction of movement of the debris through the chamber 59 so as to encourage debris to pass from the tube 125, which is of generally rectangular cross-section, into a generally circular crosssection spigot 1 26 which extends rearwardly of the chamber 59. The compressed air supply is obtained from hose 71' via a connection which is not shown.

The spigot 1 26 receives a sleeve 1 27 with an Oring 1 28 firmly wedged between the spigot 1 26 and the sleeve 1 27 to provide an airtight connection the spigot 1 26 having an annular groove 128' to receive the O-ring 1 28. The sleeve 1 27 is received and fixed in airtight manner within the flexible hose 58.

Both sleeve 1 27 and spigot 1 26 have annular grooves 126', 127' which when aligned, permit the insertion of ball bearings B through a tapped hole T to permit rotational movement of the sleeve 1 27 relate to spigot 1 26.

Various modifications may be made to the apparatus described without departing from the scope of the invention. For example, if desired T.V. camera 60 and/or spray head 63 may be omitted if not required, or any alternative means of monitoring operations within the sewer and/or providing a water jetting facility may be provided.

In place of providing a hydraulic actuator 100 to operate the crushing device 52, if desired a pneumatic means may be provided or even an electric motor, although the hydraulic actuator described or an alternative hydraulic means, is preferred as this provides adequate power to crush even the hardest debris such as engineering bricks which are sometimes found in subterranean sewers.

In place of the visor 110, any other visorlike means for obturating the aperture 111 to selected degrees may be required. If desired the visor 110 or other obturating means may be remotely operable by pneumatic, hydraulic or electrically operated means, although in the embodiment described the visor 110 is merely pre-set in one of three operative positions to provide different degrees of suction through the aperture 111.

Of course, if desired three jaw members 11 3 such as shown in Figure 3 need not be provided. Only one, or two or more than three jaw members may be provided as required and the stationary jaw members 11 5 may be omitted if not required although are preferably provided so as to prevent any debris from passing beneath the jaw members 11 3 without being subjected to a crushing action.

In a modified arrangement, means are provided to facilitate steering of the apparatus 50 along the duct. Such means may comprise a hydraulic or pneumatic actuator which acts on the flexible connections i.e. the hoses. This reduces the risk of any tendency of the apparatus to rotate longitudinally. If necessary, the T.V. camera 60 may be provided with means, such as an azimuth, to detect any such longitudinal rotation of the apparatus 50, so this can be corrected.

Claims (18)

1. An apparatus to remove debris from concealed ducts, comprising a crushing device including at least one jaw member which is reciprocated by power means along a predetermined path to act upon any large pieces (as herein defined) of the debris to crush and hence reduce the size of the large pieces of debris, a hose attached to the crushing device, and means to reduce the pressure within the hose to draw the debris into an opening in, and along, the hose to a discharge station externally of the duct.

2. An apparatus as claimed in claim 1, wherein said at least one jaw member is reciprocated in an arcuate path about a pivot axis.

3. An apparatus as claimed in claim 2, wherein a plurality of jaw members are disposed to provide an array across substantially the entire width of an opening in the crushing device through which the debris is drawn.

4. An apparatus as claimed in claim 3, wherein all said jaw members reciprocate about a common axis.

5. An apparatus as claimed in any one of the preceding claims, further comprising one or more stationary jaw members adapted to co-operate with said at least one jaw member.

6. An apparatus as claimed in any one of the preceding claims, wherein the power means causing reciprocation of said at least one jaw member is one or more hydraulic actuators linked to the or each jaw member.

7. An apparatus as claimed in any one of the preceding claims, further comprising a chute means to urge the debris into said opening and means to vibrate the chute means.

8. An apparatus to remove debris from concealed ducts comprising a hose, means to reduce the pressure within the hose to draw debris into an opening in, and along, the hose to a discharge station externally of the duct, chute means to urge the debris into said opening, at least part of the periphery of the said chute means being in contact with or adapted to lie closely adjacent to the inside wall of the duct, and means to vibrate the chute means.

9. An apparatus as claimed in either claim 7 or claim 8, wherein the means to vibrate the chute means in parts thereto a reciprocating movement in a direction generally longitudinally of the duct.

10. An apparatus as claimed in any one of claims 7 to 9, wherein the means to vibrate the chute means comprise one or more pneumatic actuators.

11. An apparatus as claimed in any one of the preceding claims, wherein said opening communicates with an aperture, the extent of which is variable by visor means.

1 2. An apparatus as claimed in claim 11, wherein the visor means is pivotable in an arcuate path between a fully open position and a fully closed position.

1 3. An apparatus as claimed in any one of the preceding claims, further comprising a chamber upstream of said opening, and means to feed fluid into the chamber in a direction generally parallel to the direction of movement of the debris.

14. An apparatus to remove debris from concealed ducts comprising a hose head having an aperture, a hose so attached to the hose head that there is generally air tight communication between the aperture and an opening in the hose, means to reduce the pressure within the hose to draw debris into the opening in, and along, the hose to a discharge station externally of the duct, and a chamber between the aperture and the opening, said chamber having means to feed fluid into the chamber in a direction generally parallel to that of movement of debris.

1 5. An apparatus as claimed in either claim 1 3 or claim 14, wherein the fluid fed into the chamber is compressed air.

1 6. An apparatus to remove debris from concealed ducts substantially as described herein with reference to any one of the accompanying drawings.

1 7. A method of removing debris from concealed ducts comprising the steps of introducing one end of a hose into the duct, the end of the hose attached thereto a crushing device, acting upon any large pieces (as herein defined) of the debris by the crushing device to reduce the size of large pieces of the debris, reducing the pressure within the hose, passing the crushed debris from the crushing device into the hose, drawing the debris along the hose to a discharge station externally of the duct at which the debris is discharged from the hose.

18. A method of removing debris from concealed ducts substantially as described herein with reference to any one of the accompany drawings.