GB2254092A

GB2254092A - Apparatus for and process of laying of pipelines in the ground

Info

Publication number: GB2254092A
Application number: GB9206644A
Authority: GB
Inventors: Klaus-Peter Thoenes; Volker Hentschel; Friedhelm Kubiak; Klaus Linde
Original assignee: Westfalia Becorit Industrietechnik GmbH
Current assignee: Caterpillar Global Mining Europe GmbH
Priority date: 1991-03-26
Filing date: 1992-03-26
Publication date: 1992-09-30
Anticipated expiration: 2012-03-26
Also published as: FR2674568A1; JPH0650087A; DE4109871A1; GB9206644D0; GB2254092B

Description

2254092 1 APPARATUS FOR AND PROCESS OF LAYING OF PIPELINES IN THE GROUND

The invention relates to pipe laying or advancing operations for creating a pipeline in the ground. In particular the invention has application in the creation of a new pipeline over the route of an old defective pipeline.consisting of stoneware or concrete pipe or the like.

For the laying of pipelines, such as so-wage conduits, drainage systems or pipelines for other uses in the ground, it is known to employ the pipe driving or advancing process in which pipe sections are advanced, by means of a pipe driving station with hydraulic rams in an excavation into the ground. See DE-3505505, DE-3803601, GB-2186899, DE-3439433 and DE3408246. In such a process, the pipe sections, i.e. the individual lengths of pipe, are placed in sequence on the end of the already advanced piping and are pressed along together until the advancing pipeline reaches a target excavation. The pipe advancing process is largely employed for the laying of pipelines with interiors classed as non-accessible to personnel and equipment. i.e interiors with nominal inner diameters below 800 mm. However the same process can be employed with pipelines greater than 800 mm in 2 internal diameter classed as accessible pipelines. if solid obstructions, for example concrete blocks or remains of building construction such as remains of a wall, a foundation or the like, are located or are expected in the ground over the route of the intended pipeline or if the pipeline has to be advanced in solid, markedly compacted or even rocky soil, a driven drill head can be is used. Such a drill head is mounted in a cutting shoe or working pipe preceding the pipeline and to allow accurate advance of the pipeline, the angular position of the cutting shoe or the working pipe can be controlled and steered by means-of control units. The dril-.head normally operates either in the cutting shoe or in the front of the working pipe. The spoil material, i.e -the drill cuttings can be carried off with the known pipe advancing apparatus either by a flushing conveyance or by means of a conveyor screw which can be driven in common with the drill head if the latter does not have Lts own,drive.

It is also known to arrange, behind the drill head, a crusher for comminuting the coarse-Particled spoil. Such a crusher can take the form, for example, of a crushing cone arranged rigidly on one wall of the 3 working pipe, with which crushing strips arranged on the back of the drill head co-operate (see DE-3811036). With a drill head mounted in the cutting shoe or working pipe, hard inclusions such as concrete blocks, remains of walls and foundations and the like can be drilled through during the advancing work and it follows that old defective pipelines of stoneware of the like, located on the advance route, can also be broken out and destroyed and consequently the new pipeline laid by the pipe advancing process can be inserted over the route of the old pipeline (DE- 3620026).

It is also known, when advancing small nonaccess.ible -pipes, initially to introduce a provisional working pipe with an accessible bore into the ground over the full advance route by the pipe advancing process and then to remove portions of the working pipe again and to replace them by the final pipeline with the small nonaccessible bare and an external diameter which does not differ significantly from that of the working pipes. During the advance of the final pipeline, the previously introduced working pipe is simultaneously pressed out to the target excavation (see DE-3122710).

An object of the invention is to provide an apparatus and process with which the pipe advancing work 4 and laying of pipelines having small non-accessible cross sections such as, in particular, drain pipes., product pipes and the like, can be carried out successfully in an economic manner even in markedly compacted or even rocky soil or even if hard intercalations such as blocks, remains of walls or foundations or even old, defective stoneTare or---concrete pipelines are located in the intended route of the new pipeline.

According to the invention, there is provided pipe laying apparatus for laying of a pipeline with a nonaccessible bore in the ground, said apparatus comprising a pressing station for advancing.pipes longitudinally in successive stages to create the pipeline, a rotatably mounted cutting device in the form of a drill or bore head. at the front of the pipeline and a conveyor which leads through the pipeline for conveying spoil from the bore head back to the pressing station; wherein the bore head is located in front of a machine _,,,,p,pe in,nhch the conveyor has its receiving end; the bore head is driven independently of the conveyor with a plurality of motors arranged in the machine pipe around the conveyor and the bore head has at least two peripherally spaced cutting rollers in an outer peripheral region which act to cut free a space in front of the machine pipe, further cutting tools which are inwardly offs et toward the axis of rotation relative to the cutting rollers and through-openings provided between the cutting rollers for the passage of cuttings or spoil material to the conveyor. Normally the pipes would be made of steel, especially where the pipeline is temporary, but a durable corrosion-resistant stoneware pipes or the like can be used as the pipes to be newly laid instead of the temporary steel pipes.

The conveyor can be conveniently a screw conveyor of multi-part construction with sections joined end-toend. As the drill or bore head is driven independent of the conveyor, the driving force is always sufficiently high for the drilling work to be performed even in hard regions of the advance route. Moreover no excessively large dimensions of the conveyor screw shaft are needed as only as much drill cuttings or spoil material can be removed by the conveyor screw from the space behind the bore head as passes through the bore head into this space, independently of the operation of the respective bore head or advancing operations. The risk of undesirable mining subsidence occurring in the drill head 6 region, for example when passing through friable soil, can therefore be avoided. The drive motors of the drill or bore head can be grouped round the axis of the central conveyor screw and arranged in the foremost advancing and machine pipes having smaller nominal diameters without excessively constricting the internal cross-section of these pipes. It is preferable to use hydraulic motors for the drill head drive.

The drill head operating in front of the working pipe cuts free the working or machine pipe over its complete diameter, preferably with a small over-cut so that -the pipeline can also advance reliably over a prolonged advance route even in solid soil formations or in hard soil intercalations while allowing for adequate controllability without excessively high advancing forces. The equipping of the drill head with cutting rollers by means of which even relatively hard inclusions in the soil can be reliably comminuted or drilled through i.-s advantageous in this respect. It is generally sufficient if only a few cutting rollers, generally only two or at most three cutting rollers are provided. Relatively great through-openings for the drill cuttings or the spoil material can still be arranged between the 7 cutting rollers even in the case of smaller pipe diameters. When using cutting rollers which are designed as multiple cutting disks, the cross- section of the working and advancing pipeline is cut free by the cutting rollers during the advancing operation to such an extent that at most only a few smaller, less highly stressed additional cutting tools such as, in particular, round shaft bits or the like, need to be arranged in the internal region of the drill head.

When laying a new pipeline over the route of an old defective pipeline of stoneware or concrete pipes or the.1ie, the old pipeline with its socket connections can,be.. destroyed by drilling with the outer cutting rollers to such an extent that unobstructed advancing of the new pipeline is possible. The old pipeline is largely broken up by the outer cutting rollers, without excessive stressing of the smaller cutting tools arranged in the inner region, so that the broken material can pass through the through-openings without obstruction.

The cutting device is preferably arranged such that the cutting rollers are rotatable round axes which incline to the axis of rotation of the drill head itself and are preferably inclined by about 450 to the axis of rotation of the drill head. The cutting rollers, 8 preferably consisting of roller disks, can advantageously operate by the undercut principle which is desirable in terms of cutting technology.

It is advisable to mount the drill head in the machine pipe such that its tool carrier or holder is arranged in front of the working-face-end of the machine pipe. The drill head may use as a tool holder a strong thickwalled plate which is provided with apertures forming the throughopenings. The tool holder preferably has, on its outer periphery between the cutting rollers, cutting strips which project toward the face and extend in an-arc round the periphery of-the tool.holder. Owing to the cutting strips, the material cut by the outer cutting rollers is pressed toward the centre of the drill head-and therefore direct to the through-openings in the drill head during the advancing work so that it is reliably carried off through the drill head. It is also advisable to arrange loading strips on the working-faceaide of.. the tool holder, the loading strips being arranged appropriately in the peripheral direction between the outer cutting rollers in the region of the through-openings preferably in such a way that they extend substantially from the outer peripheral region of 9 the tool holder or from said cutting strips to the central region of the drill head and can overlap the throughopenings in the end regions. The loading strips grasp the drill cuttings or spoil material during the advancing and drilling work and assist the discharge thereof to the through-openings in the drill head. The cutting tools or round shaft bits which are offset inwardly relative to the outer cutting rollers can be arranged in the region of the loading strips or even on them.

The cutting tools which are offset inwardly relative to the outer cutting rollers are preferably mutually. offset radially with respect to the axis of rotation of- the bore head in front of terminal limiting means of the through-openings on the tool holder of the bore head in the tool mountings. The device can also be constructed and arranged such that a plurality of cutting tools or round shaft bits operate in the same cutting track.

The above-mentioned through-openings at the drill head are preferably designed substantially in the form of a segment of a ring and are located with their arc-shaped outer limiting contours substantially in the outer peripheral region of the tool holder or its cutting strips. The walls which limit the through-openings in 1.

their outer peripheral region are appropriately substantially conical in design such that they are inclined inwardly toward the rear of the cutting device.

In a preferred design, the drill head has two cutting rollers, preferably multiple cutting disks, which are mutually offset by 1800y with two arcshaped throughopenings being arranged between the cutting rollers in the peripheral regions on the tool holder.

According to a further preferred design feature of the invention, a peripherally closed crushing chamber for the drill cuttings or the spoil material is arranged between the receiving end of- the conveyor arranged centrally in the working pipe and the rear of the drill head. Larger pieces of debris can be further broken up in this crushing chamber before entering the conveyor. It is advisable to arrange, in the crushing chamber, a crushing tool which is appropriately mounted on the back of the drill head. This crushing tool advantageously consists..of a crushing cone or the like which is mounted on the drill head but rotatable around an axis of rotation offset relative to the axis of rotation of the drill head. This mounting of the crushing cone results in an advantageous crushpromoting impact effect on the 11 material located in, the crushing chamber during rotation of the drill head.

It is also advisable to arrange, in the machine pipe, an annular member, surrounding the crushing chamber, with a face which tapers conically toward the convey screw and forms a crusher opposing face cooperating with-the crushing cone.

The angular position of the machine pipe preceding the piping to be advanced can be appropriately adjustable and steered by means of hydraulic control units to enable the advancing direction to be influenced and to allow accurate-.advance of the pipeline from the rear or advance pressing station, as is known.

In another aspect of the invention there is provided a process for the laying of a pipeline by the pipe advancing process, in particular for the laying of the pipeline along the route of an old defective pipeline consisting of stoneware or concrete.pipes or the like, said process comprising installing a temporary protective pipeline composed of steel pipes by driving a bore head in front of a machine pipe to drill out the advancing cross-section to the complete external diameter of the temporary pipeline, removing the drill cuttings or spoil material with a conveyor which is arranged behind the 12 bore head and driven independently of the bore head, advancing the temporary pipeline and removing the temporary pipeline from the ground in portions during the simultaneous advancing of the pipeline which is to be newly laid. The pipes used for the temporary pipeline have a bore which is non-accessible and is greater than the.bore of the pipeline to be newly laid.

In a further aspect of the invention there is provided a process for the laying of a pipeline by the pipe advancing process, in particular for the laying of the pipeline along the route of an old defective pipeline consisting of stoneware or concrete pipes or the like; said:.process comprising installing a temporary protective pipeline composed of steel pipes by driving a bore head in front of a machine pipe to drill out the advancing cross-section to the complete external diameter of the temporary pipeline, removing the drill cuttings or spoil material with a conveyor which is arranged behind the -bore head.and is driven independently of the bore head, advancing the temporary pipeline and removing the temporary pipeline from the ground in portions during the simultaneous advancing of the pipeline which is to be newly laid. The height of the advancing axis of the 13 temporary pipeline is adapted to the height of the laying axis of the old pipeline as a function of the bore of the subsequent pipeline so that the latter is laid with the same floor as the old pipeline with respect to the bore of the old pipeline.

In a preferred process, described hereinafter, a pipeline,consisting of stoneware or concrete pipes or the like with a non-accessible bore is installed in the ground by the pipe advancing process and the process is particularly advantageous for the laying of the pipeline along the route of an old defective pipeline with a nonaccessible bore consisting of stoneware or concrete pipe or the.like. As mentioned previously, a provisional or temporary protective pipeline of steel pipes is firstly driven over the advancing route by the pipe advancing process and is subsequently removed or pressed out from the ground in portions during the simultaneous advancing of the pipeline which is to be newly laid. In contrast, in a process known from DE-PS-3122710, steel piping is initially advanced over the entire route between a launching excavation and a target excavation and the steel piping has an accessible bore, that is a nominal diameter of 800 mm or greater. Deviating from this known process, there is introduced into the ground, by the 14 process according to the invention, a temporary protective pipeline with a bore which is non-accessible but is greater than the bore of the pipeline to be newly laid. The advance path of the temporary protective pipeline is drilled open to the complete external diameter of the protective pipe by means of a driven cutting device and the, drill cuttings and spoil material are supplied through the cutting device to a conveyor, such as a screw conveyor.. which is arranged with its receiving end behind the cutting device and is driven independently of the cutting device with the material passing along the conveyor and.through the protective pipeline. The pipe advancing apparatus according to the invention can be used particularly advantageously with this process. The advantages of the process according to the invention reside, in particular, in the fact that a large-calibre protective pipeline accessible to personnel can be replaced by a pipeline having a non- accessible nominal.diameter.. so that the pipe advancing work is simplified and that the subsequent introduction of the pipeline which consists of stoneware pipes or the like and is to be newly laid is considerably simplified and the stoneware pipes cannot be damaged. This process also is allows the laying of Pipelines having very small diameters even if hard inclusions are located on the advance route, for example a defective old pipeline which is to be replaced by the pipe to be newly laid.

The invention may be understood more readily, and various other aspects and features of the invention may become apparent, from consideration of the following desription.

Embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawings, wherein:

Figure I is a schematic simplified longitudinal section. through a pipeline and apparatus constructed in accordance with the invention; Figure 2 is a longitudinal section through the forward zone of the apparatus, the view being taken on a larger scale to Figure 1; Figure 3 is an end view of the boring head of the apparatus as seen in the direction of arrow X in Figure Figure 4 is a cross-sectional view of part of the apparatus, the view being taken along the line IV-IV of Figure 2; Figure 5 is an end view of a modified boring head 16 for use with the pipe driving apparatus; the view corresponding to Figure 3 but being taken on a larger scale and Figure 6 is a schematic sectional side view of the boring head shown in Figure 5.

The apparatus depicted in Figure 1 serves to advLnce plpgs end-to-end to form a pipeline or pipe string beneath the ground. To aid in understanding the operation of the apparatus reference may be made to GB2186899, DE-3505505 and DE-3803601.

As is known, the apparatus employs a pressing station 2 in a launching excavation 1 such as a trench or duct,.., The pressing or advancing station 2 has a plurality of hydraulic rams 4 which are supported on an abutment 3 and advance via a thrust collar 8 sections of steel piping 7 in the direction of arrow 6 into the ground 5 in the direction of a target excavation (not shown). Fresh pipes 7 are introduced one by one into the excavatiQn.l. Each pipe 7 rests an a pipe support 9 and can then be pressed in the direction of the arrow 6 by the rams 4 together with the pipeline composed of previously installed pipes 7 already advanced into the ground 5. The design of the advancing station 2 is not of 17 any special significance and conventional pressing stations for pipeline advancing processes can be used for this purpose, in particular the type known from GB2186899.

The pipeline formed by the pipes 7 disposed end-to-end is preceded by a working machine pipe 10 and an intermediate pipe 11 disposed between the pipe 10 and the pipeline. The machine pipe 10 is of special construction and incorporates a drill or bore head 26 described hereinafter. The pipes 10 and 11 can also consist of steel pipes with an external diameter corresp9pding to that of the pipes 7. The pipes 7, 10 and 11. are usually non-accessible having a nominal width or an internal diameter of less than 800 mm.

At a working station at the end of the pipeline remote from the pressing station the machine pipe 10 confronts an old defective pipeline 12 which is to be replaced by the new pipeline composed of the pipes 7. The old pipeline can typically consist of stoneware pipes or the like of which connecting sockets are designated 13. The internal and external diameter of the pipes of the old pipeline 12 are considerably smaller than that of the pipes 7, 10 and 11.

As shown, in particular, in Figure 2, the 18 intermediate pipe 11 is rigidly connected to the foremost pipe 7 which is at the front in the advancing -direction at a screwed joint 14. The other front end 15 of the pipe 11 fits into the rear end of the machine pipe 10 with a flexible seal 15 therebetween permitting the machine pipe 10 to be angularly inclined all around relative to the intermediate pipe 11 to control the advancing direction and to ensure accurate advancing of the pipeline. The control is carried out, as known, by means of a plurality of hydraulic control units 17 (typically four) which are merely indicated in Figure 2 and are articulated to the pipes 10 and 11. A laser targeting device 18 can be arranged in the intermediate pipe 11, as also known.

In the centre of the pipes 7, 10 and 11 there is located a conveyor 19 with a rotary shaft 20 carrying screw flights 21 and 22. The shaft 20 and screw flights 21, 22 are supported in conveyor pipes 23 and 24 located centrally An the pipes 7, 10 and 11. The conveyor 19 consists of individual sections which are connected to one another end-to-end and extend through the machine pipe 10 through the pipe 11 and through the already advanced pipes 7 back into the excavation 1. The 19 discharge end of the conveyor 19 is consequently located in the excavation 1 so that the conveyed spoil can be discharged here into spoil containers 25 located below the pipe support 9. The design of the conveyor 19 composed of sections is described in GB-2186899. The screw flight 21 of the conveyor 19 located within the machine pipe..10 and the intermediate pipe 11 and the pipes 23 have a smaller diameter than the flights 22 the pipes 24 respectively in the piping formed by pipes 7 so that sufficient space remains inside machine pipe 10 around the conveyor 19 and its pipe for thg.arrangement of drive motors 30 driving the head. 26..

and the the 23 bore The machine pipe 10 proper ends at 27 and the bore head 26, which can take the form of a drill bit, rests, together with its tool holder 28 against the machine pipe 10. The tool holder 28 consists of a strong thick-walled plate with a diameter corresponding to the external diameter of the machine pipe 10. The conveyor 19 terminates with its receiving end 29 inside the machine pipe 10 at a short distance behind the bore head 26 or its tool holder 28. The conveyor 19 has its own drive which is located at the end of the conveyor or its drive shaft 20 guided into the excavation 1. The bore head 26 also has its own drive in the form of the drive motors 30, (Figure 4), arranged around the receiving end 29 of the conveyor 19. Some six drive motors 30 constructed as hydraulic motors are shown in the illustrated embodiment. The bore head 26 is driven via pinions 31 (Figure 2) meshing with a crown wheel 32 of a hollow gear-wheel which surrounds the conveyor pipe 23 and is mounted in the machine pipe 10 in an anti-friction bearing 34. The hollow gear-wheel 33 is non-rotatably connected at the rear to the tool holder 28. The bore head 26 is consequently rotatably mounted in the machine pipe 10 and is driven by the motors 30 grouped round the conveyor 19 and-calso arranged in the machine pipe 10.

As shown in the versions depicted in Figure 3, 4 and.5, the bore head 26 has, in its outer peripheral region a cutting ring 39 and two cutting rollers 35. The rollers 35 are mutually offset by 1800 in the peripheral direction and are mounted on the working-faceaide in---roller brackets 36 of the tool holder 28. The rollers 35 are freely rotatable around axes 37 set out about 450 relative to the axis of rotation 38 of the head 26. The cutting rollers 35 are designed as multiple cutting disks, as shown, their disk cutting edges which 21 are greatest in diameter cutting the outer peripheral region of the head 26 and of the machine pipe 10, preferably with a slight over-cut, during operation.

The cutting ring 39, which projects toward the working face is rigidly mounted on the outer periphery of the tool holder 28 and in front of the end face 27 of the machine pipe..10. The ring 39 extends over the entire outr periphejry of the tool holder 28, but optionally has an interruption or recess in the region of each of the cutting rollers 35. In the peripheral regions between the cutting rollers 35, the tool holder 28 has apertures which form through-openings 40 for the passage of the drill.. cuttings or the spoil material. These throughopenings 40 extend in the form of arcs between the cutting rollers 35. The openings 40 are each designed substantially in the form of a segment of a ring, their outer arc-shaped limiting contours 41 extending substantially in the peripheral region of the tool holder 28 in the region of the footline of the annular cutting ring 39. The walls 42 limiting the through-openings 40 in the outer peripheral region are inclined conically toward the rear so that the through-openings 40 taper toward the rear of the plate-shaped tool holder 28. The openings 40 run out into a crushing chamber 43 which is 22 located between the rear of the head 26 and the receiving end 29 of the conveyor 19 and is limited at the.periphery by an annular member 44 which is arranged rigidly in the machine pipe 10 and of which the internal face 45 tapers conically toward the receiving end 29 of the conveyor 19 and forms a conical opposing crusher face. On the working-facerside of the tool holder 28 there are fastening loading strips 46 (Figure 3 and 5) which are arranged peripherally between the cutting rollers 35 in the end region of the through-openings 40 and extend from the central region of the tool holder 28 substantially to the encircling cutting ring 39. In the embodiment according to Figure 3, the loading strips 46 are angled off and extend over the entire width of the throughopenings 40. In the emb odiment according to Figure 5, on the other hand, the loading strips 46 are straight and extend from the cutting ring 39 substantially to the arc contour of the cone face 42 located on the rear of the.tool holder 28.

In the embodiment of the head 26 according to Figures 2 and 3, further cutting tool in the form of rollers 47, also consisting of cutting disks, are rotatably mounted, in roller brackets, on the tool holder 23 28 in the peripheral region between the outer cutting rollers 35 but offset relative thereto in the direction of the axis of rotation 38 of the drill bit. The axes of rotation of the cutting rollers 47 extend substantially radially to the axis of rotation 38 of the head 26. The cutting tools formed by the cutting rollers 47 cut the inner,region of the face during the drilling operation.

In the embodiment according to Figures 5 & 6, round shaft bits 48 in bit mountings 49, which operate as tangential bits, are arranged at different radial distances from the axis of rotation 38 of the head 26 on the to9l holder 28. The bits 48 are offset relative to the outer cutting rollers 35 toward the axis of rotation 38 and serve as further cutting tools. The bits 48 are arranged in pairs on diametrally opposed sides of the axis of rotation 38 and at different radial intervals from the axis of rotation 38. It will be appre&iated that the number of bits 48 can differ and that the bits 48 can also be arranged such that a plurality of bits run in the same cutting track in each case, i.e. are at the same radial distance from the axis of rotation 38. The bits 48 are located peripherally in the substantially radially extending end regions of the through-openings 40 in the region of the loading strips 46. The loading 24 strips 46 shown inFigure 3 can also be provided in the embodiment according to Figure 5. In this case, the bits 48 can also be arranged on the loading strips 46 or with their bit mountings 49 in recesses thereof.

On the rear of the plate-shaped tool holder 28 of the head 26 there is arranged a crushing tool in the form of a crushing cone 50 which projects substantially centrally into the crushing chamber 43 and is mounted on the tool holder 28 for rotation around an axis 51 which extends parallel to the axis of rotation 38 and is offset slightly in the radial direction relative thereto. The crushing cone.50 can have crushing strips.52 or the like on its.conical outer periphery.

During the advancing work with the bore head 26, the crushing cone 50 normally participates in the rotational movement of the head 26 owing to the bearing friction. The drill cuttings or spoil material passes through the through-openings 40 into the crushing chamber.43. If coarse-particled material jams in the crushing chamber 43 between the crushing cone 50 and the opposing crusher face 45, the rotational movement of the crushing cone 50 is blocked. The eccentric axis of rotation 51 of the crushing cone 50 is however entrained by the head 26 and therefore rotates round the axis of rotation 38 when the crushing cone 50 is stationary. The material jammed between the crushing cone 50 and the opposing crusher face 45 therefore experiences a type of hammering action as the crushing cone 50 performs a movement radially by the amount of the offset of the axis of rotation. This hammering movement leads to impacting and squashing of the coarse-particled crushed material. The material located in the crushing chamber 43 can therefore pass via the receiving opening 29 into the conveyor 19 and is carried off to the excavation 1.

Figure 6 shows that the plate-shaped tool holder 28 has,. in- the bearing region of the outer cutting rollers 35, apertures 53 which are open toward the crushing chamber 43 so that any spoil can pass through these openings 53 into the crushing chamber 43 and therefore into. the receiving region of the conveyor 19.

As shown in Figure 2, a water supply 54 is provided which is guided through the machine pipe 10 and by means of which flushing water can be introduced into the crushing chamber 43 in order to assist the passage of the spoil through the crushing chamber 43 into the conveyor 19.

Figure I shows that, during the pipe advancing 26 operation, the rotating head 26 with its cutting rollers 35 operating in the outer peripheral region attacks the old pipeline 12 at least in the region of the pipe sockets 13. Thus, the structure of the stoneware pipes of the old pipeline 12 is destroyed by means of the internal cutting tools 47 (Figure 3) or 48 (Figures 5 and The pipe debris is pressed, together with the soil material surrounding the old pipeline, inwardly the through-openings 40 by the cutting ring 39 arranged on the periphery of the tool holder 28 with, the loading strips 46 assisting the supply of the spoil to the through-openings 40. The spoil then passes in the described manner through the openings 40 into the crushing chamber 43 and thence into the conveyor 19.

In this way, the pipeline consisting of the steel pipes 7 can be advanced with simultaneous destruction of the defective old pipeline 12, over its route to the target excavation. with the pipeline consisting of the.steel pipes 7 being advanced with the same floor as the old pipeline 12. This means that, owing to the different diameter of the pipelines, the pipeline consisting of the pipes 7 and the frontal pipes 10 and 11 is advanced in the ground 5 such that its axis is offset in height 27 relative to the axis of the old pipeline 12.

Power and supply lines from the target excavation or from the excavation 1 through the pipes 7 to the machine pipe 10 are appropriately constructed in the manner known from GB-2186899. Thus the pipes 7, 10 and 11 have at least one conduit which is continuous over the length of the- pipes and serves to receive supply lines and the like and is sealed at the pipe periphery by means of covers after insertion of the supply and power lines.

It is advisable, in particular during the laying of drainage or sewage conduits as replacement for the old defective pipeline, subsequently to replace the pipeline which.consists of the steel pipes 7 and is advanced over ---1 the complete pressing route with another pipeline consisting of more durable stoneware or concrete pipes or the like. This can be carried out advantageously in that the new pipeline of which the pipes have the same external diameter as the steel pipes 7 but a smaller inner diameter are advanced from the excavation 1 the by same pipe advancing process. The temporary pipeline consisting of the steel pipes 7 is then simultaneously pressed out to the target excavation in the direction of the arrow 6 as the new pipeline advances and the pipes 7 can be dismantled and removed here for use again. with 28 this process, therefore, the pipeline consisting of the steel pipes 7 therefore forms merely temporary protection which is subsequently replaced by the new pipeline consisting of stoneware or concrete pipes. It will be appreciated that, during the advance of the new pipeline and simultaneous removal of the temporary pipeline formed by the steeLpipes 7, the bore head 26 and spoil conveyor 19 can be dispensed with so that the introduction of the new pipeline can be carried out easily and quickly.

Application of the apparatus according to the invention is however not restricted to the introduction of a new pipeline as a replacement for an old defective pipeline. Indeed, the pipe laying process can advantageously be used for any type of pipe advancing operation, particularly if hard intercalations of the above-mentioned type are expected on the pipe advance route or pipes with a non-accessible bore are to be advanced in markedly compacted or even rocky soil.

29

Claims

CLAIMS I.Pipe laying apparatus for laying of a pipeline in the ground,

said apparatus comprising a pressing station for advancing pipes longitudinally in successive stages to create the pipeline, a rotatably mounted cutting device in the form of a drill or bore head at the front of the pipeline,and a-conveyor which leads through the pipeline for conveying spoil from the bore head back to the pressing station; wherein the bore head is located in front of a machine pipe in which the conveyor has its receiving end; the bore head is driven independently of the conveyor with a plurality of motors arranged in the machine pipe around the conveyor and the bore head has at least two peripherally spaced cutting rollers in an outer peripheral region which act to cut free a space in front of the machine pipe, further cutting tools which are inwardly offset toward the axis of rotation relative to the cutting rollers and

0 through-openings provided between the cutting rollers for the passage of cuttings or spoil material to the conveyor.
2. Apparatus according to Claim 1, wherein the bore head has a rotatable tool carrier carrying the rollers and tools and the carrier is arranged in front of the working-face-end of the machine pipe.
3. Apparatus according to Claim 1 or 2, wherein the cutting rollers are arranged with equal radial spacing from the axis of rotation but are rotatable around axes which are inclined to the axis of rotation of the bore head and preferably at about 450 to the axis of rotation of the bore head.
4. Apparatus according to Claim 1, 2 or 3 wherein the bore head has a cutting ring which extends over the outer periphery of the bore head toward the working face and is recessed in the region of the cutting rollers.
5. -,.-.Apparatus according to any one of Claims 1 to 4, wherein the bore head further comprises loading strips for assisting the passage of material to the conveyor.
6. Apparatus according to Claim 5, wherein the loading strips are arranged in the peripheral direction between the cutting rollers in the region of the throughopenings,.
7. Apparatus according to Claim 5 or 6, when appended to Claim 4, wherein the loading strips extend substantially from the cutting ring to the central region of the bore head.

31
8. Apparatus device according to Claim 2 or any one of Claims 3 to 7, when appended to Claim 2, wherein the tool carrier consists of a thickwalled plate which is provided with apertures forming the throughopenings and optionally apertures in the bearing regions of the outer cutting rollers.
9., Apparatus according to any one of Claims I to 8, wherein the cutting tools are radially offset from one another relative to the axis of rotation of the bore head in front of terminal limiting means of the throughopenings.
10. Apparatus according to any one of Claims 2 or 4 or any one.,of Claims 3 or 5 to 9 when appended to Claim 2 or 4 wherein the through-openings extend with outer arcshaped limiting contours on the working-face-side substantially up into the outer peripheral region of the tool carrier or of the cutting ring.
11. Apparatus according to any one of Claims I to 10 wherein the cutting rollers are mutually displaced by 1800 and the through-openings are arcshaped.
12. Apparatus according to Claim 2 or any one of Claims 3 to 11, when appended to Claim 2, wherein the walls of the tool carrier limiting the through-openings in the outer peripheral region are inclined substantially 32 conically toward the rear of the bore head.
13. Apparatus according to any one of Claims 1 to 12, wherein a crushing chamber is arranged between the receiving end of the conveyor and the rear of the bore head.
14. Apparatus according to Claim 13x wherein a crushing tool is arranged on the rear of the bore head in the crushing chamber.
15. Apparatus according to Claim 14, wherein the -crushing- tool consists of a crushing cone which is mounted for rotation on an axis of rotation offset relative to the axis of rotation-of the bore head.
16.-;-Apparatus according to Claims 14 or 15, wherein an annular member is arranged in the machine pipe to surround the crushing chamber, the member having an internal cone face which extends toward the receiving end of the conveyor and forms an opposite crusher face for the crushing tool.
1-7. Apparatus according to any one of Claims 14 to 16, and further comprising flushing water supply means for supplying water to the crushing chamber.
18. Apparatus according to any one of Claims 1 to 17, and further comprising a hollow rotatable gear mounted in 1 33 the machine pipe and surrounding the conveyor and a crown wheel with which the pinions of drive motors usedfor driving the bore head mesh.
19. Apparatus according to any one of Claims 1 to 18, wherein the conveyor is a screw conveyor which is stepped to have a smaller size in an end region located in the machine pipe..than in its longitudinal region located i. 'i..

therebehind.
20. Apparatus according to one of Claims I to 19, wherein the machine pipe is mobile and can be inclined all around relative to the pipeline by means of hydraulic control.units for direction control.
21. Apparatus substantially as described with reference to, and as illustrated in, any one or more of the Figures of the accompanying drawings.
22. Process for the laying of a pipeline by the pipe advancing process, in particular for the laying of the pipeline along the route of an old defective pipeline consisting of stoneware or concrete pipes or the like; said process comprising installing a temporary protective pipeline composed of steel pipes by driving a bore head in front of a machine pipe to drill out the advancing cross-section to the complete external diameter of the temporary pipeline, removing the drill cuttings or spoil 34 material with a conveyor which is arranged behind the bore head and is driven independently of the bore head, advancing the temporary pipeline and removing the temporary pipeline from the ground in portions during the simultaneous advancing of the pipeline which is to be newly laid, wherein the pipes used for the temporary pipeline have a bore which is non-accessible and is greater than the bore of the pipeline to be newly laid.
23. Process according to Claim 22 and further comprising breaking up coarse-particled drill cuttings by means of a crusher mounted on the rear of the bore head within a crushing chamber arranged between the bore head and-the receiving end of the conveyor.
24. Process according to Claim 22 or 23, wherein the old pipeline is broken out and destroyed by the rotating bore head as the temporary pipeline is being created.
25. Process according to one of Claims 22 to 24 and further comprises introducing flushing water into the -receiving region of the conveyor.
26. Process for the laying of a pipeline by the pipe advancing process, in particular for the laying of the pipeline along the route of an old defective pipeline consisting of stoneware or concrete pipes or the like; such process comprising installating a temporary protective pipeline composed of steel pipes by driving a bore head in front of a machine pipe to drill out the advancing cross-section to the complete external diameter of the temporary pipeline, removing the drill cuttings or spoil material with a conveyor which is arranged behind the bore head and is driven independently of the bore head, advancing the temporary pipeline and removing the temporary pipeline from the ground in portions during the simultaneous advancing of the pipeline which is to be newly laid during the advance of the temporary pipeline, wherein....the height of the advancing axis of the temporary pipeline is adapted to the height of the laying axis of the old pipeline as a function of the bore of the subsequent pipeline so that the latter is laid with the same floor as the old pipeline with respect to the bore of the old pipeline.
27. Process for laying a pipeline substantially as described herein with reference to, and as illustrated in the accompanying drawings.