GB2130333A - Process and apparatus for cleaning sewer pipes - Google Patents

Abstract

In a process of cleaning sewer pipes, wherein a mixture is sucked off, a suspension is formed from the residues in the sewer in front of the apparatus and at least a lower layer of that suspension is sieved and, as far as relatively large objects are concerned, is mechanically disintegrated. Subsiding objects are removed upwardly from an accumulation into a sucked stream. The apparatus comprises a jetting device (7), particularly an array of air-water nozzles, which serves to form a suspension, and behind said jetting device (7) comprises a driven disintegrating rake (8) which constitutes a deflector and is driven to enter the material in an upward direction and which pushes accumulated material ahead and/or throws it above the rake (8) for removal overhead. The disintegrating rake (8) comprises sawbladelike disintegrating blades, which extend at an angle in excess of 45 DEG from the horizontal and are driven by an eccentric drive to push material ahead in an upward and forward direction. <IMAGE>

Description

SPECIFICATION Process and apparatus for cleaning sewer pipes This invention relates to a process of cleaning sewer pipes, wherein a mixture is sucked off.

The invention also relates to apparatus for cleaning sewer pipes, comprising a disintegrator, which serves to act on a deposited layer and includes disintegrating units, and a conduitfor pumping off a water-sludge mixture, which conduit is associated with said disintegrating units at the rear thereof.

Such apparatus for cleaning sewer pipes is known from Laid-open German Application 30 25 586, but in that apparatus the disintegrating units consist substantially of rotary heads, which dig into a deposited layer and discharge said deposited layer rearwardly into the pumping conduit.

The disintegrating heads ofthe disintegrating unit precede a funnel, which communicates with a pumping-offconduit. The advanceable arrangement comprising the disinterating unit is erected in front ofthe deposited layer so that the latter can be acted upon from itsfrontend.

That arrangement results in a considerable darning action, particularly because the disintegrating heads may stick in the funnels; in that case the material to be removed will exert a sealing action. This will particularly be the case if the composition delivered to the pumping conduit is no longer suitable for being pumped off. Forthis reason, water under pressure and compressed air for loosening the deposited sludge are supplied to the disintegrating heads in the known apparatus. This measure is intended to effect not only a loosening but also to increase the rate at which soil is handled by a conveyor pump. Nevertheless, the solids which form a suspension when they have been loosened will subsequently settle again becausethe known disintegratordraws in the solids so that clogging may occur.

It has already been proposed (German Patent Application P31 10 446.0-25) to provide apparatus for cleaning sewer pipes with a disintegrating device having disintegrating blades which are similarto saw-blades and extend substantially parallel to the longitudinal axis ofthe apparatus and are adapted to be driven by means of a crankshaft or an eccentric shaft provided with symmetrically offset eccentric discs. In that case the disintegrating blades extend substantially horizontally and have teeth which are similarto saw-teeth having steep side faces which extend downwardly and rearwardly atthe forward edge ofthe indentation, and said disintegrating blades are driven to move the solids towards the pumping-off conduit and to distroy bulky objects, if possible. The result will greatly depend on the nature of the objects.

The known apparatus comprisesa lowerscraping plate, which increases the resistance to the advance of the apparatus so that the apparatus will soon be blocked after its operation has been started.

In the operation of the known apparatus and ofthe proposed apparatus it must be borne in mind that the consistency ofthe deposits is not known in most cases. This facet gives rise to the problem that when the apparatus is uniformly advanced by a traction rope secured to the front end ofthe apparatus or by a motor-driven truck pushing from the rear the solids will accumulate in an uncontrolled manner and will finallyexerta damming action becausethemannerin which the solids are discharged cannot be predicted.

Whereas it has been mentioned in connection with the known apparatus thatthe layer deposited in sewers may consist of sludge or of a water-sludge mixture, the advance of the apparatus will always result in a damming action. Besides, the deposits in a sewer pipe will not always consist ofsludge but may consist of a thickened, dry mass, which can be taken up only in an extremely complicated manner and with the exertion of considerably forces.

It has already been proposed, also in conjunction with the use of a disintegrator,to provide at the forward end ofthe apparatus a water nozzle for stirring up deposited solids so astoform a suspension.

But if that concept is adopted in conjunction with the use of disintregating blades, a drawing-in motion may cause the apparatus to climb in the sewerwhich is to be cleaned. This will particularly occur if a scraper plate is disposed and the disintegrating blades and retaining teeth are provided on said scraping plate and serve to ensure that solids will be disintegrated by the objects which are conveyed by the disintegrating blades, which are driven downwardly and rearwardly.

The solids may be so strong that the disintegrating mechanism will be blocked.

It is an object ofthe invention to provide a process which ensures an improved removal of the solids whereas clogging will be avoided, and so to improve an apparatus which is of the kind described first hereinbefore and comprises a disintegratorthatthe apparatus when driven by extraneous drive means, particularly by traction, will process the solids, parti cularlythe solids deposited in a sewer pipe and will discharge them by an action performed atthe speed at which the apparatus is advanced and said solids will not accumulate so as to result in a damming action or clogging.

That object is accomplished buy a process in which a suspension of the residue in the sewer is formed and is divided in front of the apparatus in dependence on the specific gravities and at least a lower layer ofthat suspension is sieved and as far as relatively large objects is concerned is mechanically disintegrated. In this manner the deposited material is processed and components having different specific gravities can be processed in different ways. The sieving serves to recover specific particles sizes.

Objects which subside during the mechanical disintegration are desirably removed from an accumulation in an upward direction to enter a sucked-off current and that conveyance results also in a reaction force which acts down-wardly on the apparatus. For this reason the dispersing action by which a suspension isformed is succeeded buy a mechanical processing ofthe contained solids during a continuous forward and upward motion. Flotable constituents which can be sucked off are moved upwardly from an accumulation to enter a sucked-off stream and are removed overhead and the apparatus is held in its operative position.

The present invention is thus distinguished by a two-step process, in which a suspension containing about 80% sands is formed first and floatable subst ancesflowoffwhereas heavy particles, such as stones, remain atthe bottom and as they are pushed forward are rejected by wall portions or by accumulations in the lower portion ofthe suspension which has been formed. It is apparentthatthe cleaning involves first a processing to form the suspension andthereaf- terra mechanical separation ofthe suspension. Because said mechanical separation causes the lightweight substances to rise, it affords the advantage that the apparatus used for cleaning is held atthe bottom of a sewer pipe.

The apparatus for carrying outthe process corresponding to the above statements is characterized in that a jet nozzle, particularlyan air-water nozzle, for forming a suspension is provided attheforward end, and a driven disintegrating rake serving as a deflector is provided and driven to enter accumulated material in an upward direction and to push accumulated material ahead and/orto throw it above the rake for removal overhead. That arrangement differs from known ones in that the driven disintegrating rake acts virtually in an opposite direction and does not serve to draw in material but assists the separation of a liquor which has been formed in front ofthe apparatus.

Adjacent to the suspension, the disintegrating rake which is driven to enter the material in an upward direction causes an upward movement ofthe floatable matter and of the sands so that a separation is effected oran overhead conveyance to the pumping-off conduit, which opens behind the disintegrator and exerts a suction action. This arrangement affords the advantages that clogging will be avoided in any case and that it is ensured thatthe apparatus is moved undertraction on the bottom of a sewer pipe because the action ofthe disintegrator driven in the stated sense ensures that the scraping plate will be held on the bottom ofthe sewer pipe in front of the opening of the pumping-offconduit and additional means, such as weights, are not required for that purpose.The impulses which are due to the upward motion of the disintegrator contribute to the loosening ofthe substances in the suspension which has been formed.

Underthe foregoing aspects, the disintegrating rake is preferably upwardly and forwardly inclined from the horizontal. This arrangement will promote the processing ofthe suspension. In a preferred arrange ment,the disintegrating rake comprises sawbladelike disintegrating blades, which extend at an angle in excess of 45" from the horizontal and are driven by an eccentricdrivesoasto push off in an upward and forward direction.

The inclination ofthe disintegrating blade from the horizontal preferably exceeds 60". This arrangement will result in special pulsesforloosening and raising the solids in the suspension and for guiding the apparatus on the bottom of the sewer pipe. But even when inclined disintegrating blades having sawtoothlike teeth are employed in conjunction with the drive means which have been described the steeper side face of each indentation will preferably be disposed underneath and the less steep side face will preferably be upwardly inclined. Such an arrangement will particularly assist the above-mentioned effect.

In a preferred arrangement, the sawtoothlike teeth ofthe disintegrating blades are provided around the lower end ofthe disintegrating blades and rearwardly in the direction of motion ofthe apparatus overthe scraping plate, which constitutes a lower part of the apparatus. That arrangement will ensurethat a sievelike barrier will be provided also on the underside ofthe disintegrating rake and during the motion of the disintegrating blades will ensure that relatively large and relative strong objects will be disintegrated orwill be rejected in a forward direction. Forthe disintegrating and sieving functionsthe disintegrating rake and particularlythe disintegrating blades are suitably provided on their sides with tearing teeth, which extend toward each other and are movable past each other.

The disintegrating blades are desirably connected attheir lower end to an eccentric drive and are guided in a cam slot at their upper end and the design adjacent to the eccentric drive is such thatthe blade is spaced buy a distance of an order of about 1/2 centimetre from the bottom ofthe housing ofthe disintegrating rake orfrom the scraping plate when that portion of a distintegrating blade which is associated with the eccentric drive is in its lowermost position. Owing to that small distance from the bottom, particularly from the scraping plate, which is guided on the bottom in front ofthe pumping-off conduit, it is ensured that solid objects such as stones or the like which cannot be disintegrated will not enter the pumping-off conduit. Such objects are continuously advanced or are thrown off laterally.Those objects which are advanced will accumulate and can be removed at certain times or at certain locations along the path of the apparatus.

The disintegrating blades ofthe disintegrating rake are driven by a transmission. In a desirableembodi- ment, thattransmission consists of a differential transmitting elements are provided at both ends of the disintegrating rake and each of said transmitting elements servesfortransmitting a powerwhich is lowerthan the total power and consists preferably of a belt drive. In that case, lateral housing parts ofthe apparatus may be narrow because only one-half of the power must be transmitted at each end to the eccentric shaft for driving the disintegrating blades.

Asthetransmitting element consists preferably of a vee belt, the differential provides for a balancing ofthe slip at both ends. Owing to the narrow design, an apparatus having an adequate working width may be designed tofitthe dimensions of a sewershaft through which the apparatus isto be intrnduced.

The apparatus preferably comprisesa disintegirat- ing rake housing having a bottom plate which constitutes a scraping plate and serves as a guiding sledge, a second sledge, which is provided with a sludge-sucking pump unit, a suction conduit which extends in front ofthe pump unit and behindthe disintegrating rake, and an articulated traction element between the disintegrating rake housing and the sledge provided with the sludge-sucking pump unit.

The side walls consist of narrow lateral frame members mounted on the guiding sledge. Owing to its division into two sledge-like subassemblies, the apparatus is highly flexible and adaptable also be cause the forwa rd end of the housi ng fo r the disintegrating rake will always be held down on the bottom. Particularly the so-called second sledge is provided with a fitting assembly for connection to a pressure sludge conduit and to a compressed air supply conduit and a pressure water supply conduit, which are connected to the at least one air-water nozzle.

The above-mentioned air-water nozzles are known, e.g., from Laid-open German PatentApplication 2913 455. In said nozzles a liquid jet is discharged together with surrounding compressed air so that special stirring-up and loosening actions will be obtained. In a preferred arrangement, a housing beam is provided at the forward end of the apparatus and constitutes an air-water nozzle bar, which is provided with more than one forwardly and downwardly directed air-water nozzles and is provided at each of its outer ends with at least one air-water nozzle which is outwardly and downwardly directed. This arrangement will permit a particularly effective cleaning of a sewer pipe.

The invention will now be explained with reference to an illustrative embodiment, which is shown in the drawings, in which Figure lisa side elevation showing the apparatus, Figure 2 is an enlarged transverse sectional view taken on line ll-ll in Figure 1, Figure 3 is an end elevation showing the air-water nozzle bar provided attheforward edge of the apparatus, Figure 4 is a side elevation related to Figure 3, FigureS is a front view showing a portion of Figure 1 for illustrating the means for driving the disintegrating rake, Figure 6 is a transverse sectional view showing the air-water nozzle bar of Figure 3 and illustrating the design of the air-water nozzles.

The illustrative apparatus comprises a disintegrating rake housing 1, which comprises a bottom plate consisting of a scraping plate 2 and serving as a guiding sledge, and two side walls, which consist of frame parts 4,5 and serve also as bearing carriers. The resulting sledgelike housing has an outer boundary edge. The frame parts 4,5 extend forwardly beyond the forward end 6 of the scraping plate 2, the forward end portionofwhich may be forwardly rounded or maytaperforwardlyto a centrally disposed pointed end. Theframe parts 4,5 constitute a lateral boundary and protectthe apparatus in use.

An air-water nozzle bar 7 is provided at the top at the forward end of the frame parts 4,5 and will be described more in detail with reference to Figures 3 and 4.

Adisintegrating rake generally designated 8 is disposed between the lateral frame parts and consists of disintegrating blades 9 to 15 (Figure 2), which extend parallel to each other in vertical planes and have a lateral spacing of an order of about 4 centimetres. The lower ends of the disintegrating blades are mounted on eccentric discs 16to 22, which are mounted on a shaft 23, which is mounted between the lateral frame parts 4, 5. The shaft 23 extends into the lateral frame parts 4,5, which consist of hollow walls and in which the shaft 23 is provided with drive wheels 24,25. Said drive wheels are engaged by transmitting means, particularly by vee belts 26,27, which attheirtop, behind the plane of Figure 2, are trained around drive wheels 28,29 (Figures 1 and 5).

The drive wheels 28,29 are mounted on respective shafts 30 and 31, which are connected to respective output gears of a centrally disposed differential 32.

The latter is driven by means of a shaft 33, which is driven via a transmission 34 by a drive motor 35. The motor 35 is centrally mounted on the lateral frame parts 4,5, e.g., on the rear edge.

The vee velts described aroused in the preferred embodiment. The differential 32 ensures that the shaft 23 will be equally loaded at both ends. Similar remarks are applicable to differenttypes of transmissions, wherethe backlash of the transmission will be balanced.

Each of the disintegrating blades 9 to 15 is provided at its upper end with a guide opening 36, which constitutes a cam slot that is guided on a slider 37. The sliders for the various disintegrating blades 9 to 15 are rotatably mounted on an axle 38, which extends between mounting brackets 39, 40, which are provided in the forward upper portions of the lateral frame parts 4,5. It is apparentfrom Figure 1 that each disintegrating blade comprises teeth 41, which are similarto sawteeth and which are disposed on the lower edge of the milling blades, which extend forwardly and upwardly from the shaft 23. These teeth 41 have steeper side faces 42 at the lower or rear edge and less steep side faces 43 at the upper or forward edge of each toothline indentation.When the shaft 23 is driven in the direction indicated by the arrow 44, the steeper side faces will move forwardly and upwardly so that suspension 45 accumulated between the lateral frame parts 4,5 will be raised substantially together with the lightweight substances and floatable particles and will be thrown above the disintegrating rake for removal overhead in the direction of the arrow 85. As a result, these particles or substances can subside onto the scraping plate 2 behind the disintegrating blades 9 to 15 and are thus supplied to a mouth 46 of a suction conduit 47. Beside the mouth 46, lateral guide plates for guiding to said mouth may be provided on the lateral frame parts 4,5.

As is apparontfrom Figure 1 the sawtoothliko teeth 41 are provided also on the rounded lower portion 48 ofthe disintegrating blades, which are moved over the scraping plate as they reciprocate so that in that region a forwardly directed impulse will also be exerted on any material present in that region or such material will be disintegrated or ground by the reciprocation so that such material can pass. The disintegrating blades 9to 15 are guided in such a manner relative to the eccentric discs 1 6 to 22 that the lower edge of the disintegrating blades, corresponding tothe rounded portion 48, will be moved toward the scraping plate until a clearance of about 0.5 centimetres has been obtained, and will be moved along the scraping plate so thatthere will be a barrierwhich prevents a passage of heavy solids, such as stones. Such heavy solids are advanced by the apparatus or may be deflected in an outward direction by means of outwardly projecting runnorlike deflectors so that a clogging ofthe suction mouth 46 will be prevented.Materials which have not been disintegrated bythe disintegrating blades or which pass between the disintegrating blades will be moved forwardly and upwardly and will be advanced in that direction.

The disintegrating blades 9 to 15 are provided with tearing teeth, which protrude on the sides of the blades and are designated, e.g., 49 to 56 forthe blades 9to 11. These tearing teeth serveto stir up and disintegrate also material which has entered between the blades. Because the disintegrating blades are upwardly and forwardly inclined, the deflection of stronger and larger pieces of material in the described forward direction will be effected or assisted.

Those tearing teeth 51 to 54 which are provided on adjacent disinteg rating blades 9, and extend into the same space between adjacent blades are so arranged that they can be moved past each other and will not contact each other as the disintegrating blades are driven. These teeth may overlap each other.

The air-water nozzle bar7 provided at the forward end is substantially rectangular in cross-section and its forward end face 61 is forwardly and downwardly inclined and has at its end two angled end portions 62, 63, which are downwardly inclined in an outward and forward direction. Two air-water nozzles 64,65 open in the intermediate portion of the front face 61, and one air-water nozzle 66 or 67 opens in the outer wall portions 62,63. The housing of the air-water nozzle bar 7 is also formed with supply passages for connection to a pressure water conduit 86 and a compressed air conduit 68, which are shown also in Figure 6. It is apparent from Figure 6 that a pressure water nozzle 69 is provided, which extends in an annular passage 70, which is supplied with compressed air.A conical ring portion 73 has been leftfree between the particularly hollow-conical outer surface 71 ofthe pressure water nozzle 69 and an inserted wall part 72, which defines the outer boundary of the annular passage 70.

Compressed air is supplied through the ring portion 73 and is blown outthrough an outlet opening 74 in the wall part 72 so that said airsurroundsthe pressure water jet.

The compressed airconduit68 and the pressure waterconduit86areshown in Figure 1.

Figure 1 shows also a second sledge 75, which rests on runners 76 and carries a sludge pump unit77 having a suction pipe, which is connected to the suction conduit 47.

The second sledge 75 is connected by at least one articulated traction element 78 to the apparatus provided with the disintegrating rake housing 1. The latter is provided at its front end with a traction coupling 79 for connection to a traction element 80, by means ofwhich the apparatus can be pulled forward and which is anchored on the lateral frame parts 4,5 or on the nozzle bar 7.

In the illustrated embodiment, a fitting assembly 81 is provided on the second sledge and is connected to the pressure water conduit 86, the compressed air conduit 68 and a pressure sludge conduit 82. Corresponding conduits are connected to that fitting assembly 81 and extend to a receiving or processing station disposed atthe rear.

The suspension is generally designated 45. It is apparentthatthe suspension consists of deposited sludge, ovorwhich a stream is flowing initially but which is dispersed in front ofthe air-water nozzle bar7 to form pumpablefine sludges at 87. A sewage surface level 83 will be obtained behind the apparatus Figure 1 shows a portion 84 of a bottom of a sewer pipe or sewerwhereasthetop portion of said sewer pipe or sewer is notshown.

Claims (19)

1. A process for cleaning a sower pipe, wherein a mixture is sucked off, characterized in that a suspension of the residue in the sewer is formed and is divided in front ofthe apparatus in dependence on the specific gravities and at least a lower layer ofthat suspension is sieved and asfaras relatively large objects is concerned is mechanically disintegrated.

2. A process according to claim 1, characterized in that objects which subside during the mechanical disintegration are removed from an accumulation in an upward direction to enter a sucked-offcurrent and that conveyance results also in a reaction force which acts downwardly on the apparatus.

3. Apparatus for cleaning sewer pipes, comprising a disintegrator, which serves to act on a deposited layer and includes disintegrating units, and a conduit for pumping off a water-sludge mixture, which conduit is associated with said disintegrating units at the rearthereoffor carrying out the process according to claim 1 or 2, characterized in that a jet nozzle, particularly an air-water noale,forforming a suspension is provided attheforward end, and a driven disintegrating rake serving as a deflector is provided and driven to enter accumulated material in an upward direction and to push accumulated material ahead and/ortothrow itabovethe rake for removal overhead.

4. Apparatus according to claim 3, characterized in thatthe disintegrating rake conveys material above the rake for delivery overhead to a suction conduit which opens behind said rake.

5. Apparatus according to clain'3, characterized in that disintegrating rake is upwardly and forwardly inclined from the horizontal.

6. Apparatus according to claim 5, characterized in that the disintegrating rake comprises sawbladelike disintegrating blades, which extend at an angle in excess of 45from the horizontal and are driven by an eccentric drive so as to push off in an upward and forward direction.

7. Apparatus according to claim 6, characterized in thatthe inclination ofthe disintegrating blades from the horizontal exceeds 60 .

8. Apparatus according to any of claims 3 to 7, characterized in thatthe disintegrating blades have sawtooth-like teeth and indentations, which have a steeper lower side face and an upwardly inclined, less steep side face.

9. Apparatus according to claim 8, characterized in that the sawtooth like teeth of the disintegrating blades are provided around the lower end ofthedisintograt- ing blades and rearwardly in the direction of motion of the apparatus over the scraping plate, which consti tutes a lower part ofthe apparatus.

10. Apparatus according to any of claims 3 to 9, characterized in that the disintegrating rake is provided particularly on the sides ofthe disintegrating blades with tearing teeth, which are directed toward each other and adapted to be moved past each other.

11. Apparatus according to claim 10, characterized in thatthe tearing teeth which are directed into the same space between adjacent disintegrating blades overlap each other.

12. Apparatus according to any of claims 3to 10, characterized in that the disintegrating blades are connected at their lower end to an eccentric drive and are guided attheir upperend in a guide slot and the design adjacent to the eccentric drive is such that the blade is spaced buy a distance of an order of about 1/2 centimetre from the bottom ofthe housing ofthe disintegrating rake orfrom the scraping plate when that portion of a disintegrating blade which is associ ated with the eccentric drive is in its lowermost position.

13. Apparatus according to any of claims 3to 12, comprising a transmission for driving the disintegrating blades of the disi nteg rati ng rake, characterized in thatthe transmission consists of a differential, transmitting elements are provided at both ends of the disintegrating rake and each of said transmitting elements servosfortransmitting a power which is lower than the total power and consists preferably of a belt drive.

14. Apparatus according to any of claims 3 to 13, characterized in that it comprises a disintegrating rake housing having a bottom plate which constitutes a scraping plate and serves as a guiding sledge, a second sledge, which is procided with a sludgesucking pump unit, a suction conduit, which extends in front ofthe pump unit and behind the disintegrating rake, and an articulated traction element between the disintegrating rake housing and the sledge provided with the sludge-sucking pump unit.

15. Apparatus according to any of claims 3to 14, characterized a fitting assembly for connection to a pressure sludge conduit and to a compressed air supply conduit and a pressurewater supply conduit, which are connected to the at least one air-water nozzle.

16. Apparatus according to any of claims 3 to 15, characterized in thata housing beam is provided at the forward end ofthe apparatus and constitutes an air-water nozzle bar, which is provided with more than one forwardly and downwardly directed air-water nozzles and is provided at each of its outer ends with at least one air-water nozzle which is outwardly and downwardly directed.

17. Apparatus according to claim 16, characterized in thatthe air-water nozzle has a nozzle orifice for discharging a pressure water jet and a surrounding annular passage for supplying compressed air, which passage enters through a substantially conical ring portion into the outer rim ofthe space which is traversed bythe pressure water jet.

18. Apparatus according to claim 17, characterized in thatthe conical ring portion tapers toward the space traversed by the pressure waterjet.

19. Apparatus substantially as hereinbefore described with reference to the accompanying drawings.