The present invention relates to a pipe guiding device for guiding a pipe. A pipe guiding device is for example a bock for supporting and guiding a pipe, or a pipe pusher for exerting an axial thrust force onto a pipe. Further, the invention relates to a method for laying a pipe into a subsurface.

EP2.192.259 in the name of the same applicant discloses a pipe pusher for use in a horizontal directional drilling (HDD) process. The pipe pusher comprises a frame which is provided with support parts for placing on a subsurface, and at least three drivable endless conveyor members which are drivably connected to the frame and which together delimit a feed-through opening for a conveyor pipeline. The endless conveyor members are configured for exerting a thrust on the conveyor pipeline if the conveyor pipeline is passed through the feed-through opening. The disclosed pipe pusher is in particular suitable when introducing pipelines which are vulnerable to damages, like PE-pipelines. The endless conveyor members have relatively large friction surfaces, allowing a high thrust to be advantageously exerted in the axial direction on the conveyor pipeline without the need for a high force pressing the endless conveyor members in the radial direction against the conveyor pipeline. This prevents slippage and the conveyor pipeline remains undamaged and undeformed as a consequence of the more evenly distributed propulsion forces. It is easier for the conveyor pipeline to pass through bends at the original start and opposing end of the drilled-out shank.

In practice it has appeared that the known pipe pusher is not fully satisfying. A drawback of the known pipe pusher from EP2.192.259 in this context is that in the application of the pipe pusher there may still occur damages like cracks and scratches to some particular pipelines. In particular, when installing product pipes, like PE-pipes, those pipes are vulnerable to damages.

In the past, numerous methods and devices have been developed for laying pipelines in boreholes and thus for undercrossing sensitive regions on the ground surface for which laying in the open pipe trench, for technical, ecological, legal or economic reasons, did not appear possible or advisable. Such trenchless laying can be sensible, for example, where the surface in the laying region cannot be passed over with heavy construction machinery (for example, marshlands, bodies of water) or where, from the ecological aspect, no building permission can be granted (for example in conservation areas) or where the use of conventional laying techniques would be too expensive (in the case of large laying depths and high groundwater level, for example).

Extensive information can be found in the literature on those laying methods which have already been used and tried and tested. In this context, a classification of the methods on the basis of controllability (controlled/uncontrolled methods), soil treatment (soil displacement/soil removal), transport of drill cuttings (mechanically, hydraulically), as well as the number of work steps (pilot drilling, backreaming, feed-in or insertion operation), has become established. Further distinguishing features are, for example, the basic geometric configuration of the drilling axis (rectilinear, curved), as well as the pipe materials (for example concrete, PE, cast iron, steel, etc.) which are to be laid by means of the respective method.

DE 10 2006 020 339.9 discloses a so called "Direct Pipe" method ("DP method") for introducing large diameter gas and oil pipelines into the ground. A gas or oilpipe is tested at a working space at the starting point for leakages and subsequently uninterrupted in one piece introduced into the ground. With this single-phase laying method, steel pipelines in a length up to about 1 ,500 m and a pipe diameter between about 800 mm and 1 ,400 mm are able to be installed. The DP method is a direct method in that it is a one-step method in which separate work steps of assembling pipe segments, pilot drilling, backreaming and laying operation are all eliminated and replaced by one work step of thrusting a pipeline as a whole in a continuous step into the ground.

A first drawback of the DP method is that it requires a large work space at the starting point for the drilling device and the length of the complete pipeline. A further drawback is that the method is dedicated to large gas and oil pipelines having a diameter of at least 800mm. In particular, the attainable laying lengths, for mechanical reasons (supplying of the drill head with hydraulic energy from above ground, etc.), are for smaller pipe diameters very limited (about 80 - 250 m). Furthermore, the surveying, as well as the operation of the control and drilling device, are relatively complicated. This high technical complexity in the DP method also requires large investment in mechanical equipment.

The general object of the present invention is to at least partially eliminate the above mentioned drawbacks and/or to provide a useable alternative. More specific, it is an object of the invention to provide a pipe guiding device to perform a method for laying pipes, wherein the method can be carried out more efficient and in a shorter time interval. In particular, it is an object to provide a method for laying small diameter pipes.

According to the invention, this object is achieved by a pipe guiding device according to claim 1.

The invention provides a pipe guiding device for guiding a pipe. The pipe guiding device may be a supporting device, also called a bock, or a driven feeding device, also called a pipe pusher. The pipe guiding device is suitable to be used in a method to guide a pipe which has to be introduced into a subsurface. A subsurface can be soil in a land application or a seabed in an off shore application. In particular, the pipe guiding device is used in a method for laying a pipe in a subsurface in which the pipe is installed in a substantially horizontal position, like in a HDD drilling technique (HDD: horizontal directional drilling) and extending from a first location at surface level to a second location at surface level. In particular, the pipe guiding device according to the invention may be used in a method for laying a cable or a cable casing in a windfarm. The cables may extend from the entry point to the access point at a seabed level in between at least two windturbine foundations.

The pipe may be a complete pipeline out of one-piece or just a pipe segment of a pipeline. Typically, the pipe is a product pipe like a gas- or oil-pipeline or a cable-casing. The pipe may be a removable drill string for drilling a pilot bore hole. Typically, the pipe has a diameter of at least 50mm, in particular at least 100mm to at most 800mm, in particular at most 400mm.

The pipe guiding device according to the invention comprises a mainframe for holding components of the pipe guiding device.

Further, the pipe guiding device according to the invention comprises at least two guiding members for engaging and guiding a pipe. The at least two guiding members define a feed-through opening. The feed-through opening has an axial axis which corresponds during an operation with an axial direction of the pipe.

According to the invention, the pipe guiding device is improved in that the pipe guiding device further comprises a subframe. The at least two guiding members are mounted to the subframe. The subframe is mounted to the mainframe, wherein the subframe is rotatable about the axial axis with respect to the mainframe. The guiding members are provided in a rotational arrangement about the axial axis of the feed-through opening with respect to the mainframe. In operation the at least two guiding members rotate together with the subframe with respect to the mainframe.

Advantageously, the rotational arrangement of the guiding members with respect to the mainframe reduces friction when a pipe is rotated. Herewith, a rotation of the pipe can be performed by consuming less power. Additionally, the reduced friction allows a more accurate rotational positioning of the pipe.

In particular, the pipe guiding according to the invention is advantageous when used in a method for introducing a pipe into a subsurface, wherein the pipe is steered through the subsurface by rotation of the pipe. In such a method a bit, in particular a drilling bit is provided at a distal end of the pipe. A solid connection is provided in between the bit and the pipe. The whole pipe can be steered by rotating the pipe about a controlled angle and so changing a rotational position of the bit. The pipe can be rotated at a proximal end to steer and direct the pipe through the subsurface. By rotating the proximal end of the pipe, the pipe will twist along its length. The rotational arrangement of the guiding members with respect to the mainframe reduces friction which occurs during rotation of the pipe. Herewith, the twist of the pipe is reduced which may result in a more accurate rotational positioning of the bit. As a result, the feeding and steering of the pipe through the subsurface may have an increased controllability.

In an embodiment of the pipe guiding device according to the invention, the guiding members are arranged in rotational symmetry around the feed-through opening. In particular, the pipe guiding device comprises at least three guiding members which are arranged in rotational symmetry around the feed-through opening. During a rotational movement of a pipe, the pipe is supported by the guide members. By positioning the guide members in a rotational symmetry, a weight of the pipe is equally distributed over the guide members during a rotation of the pipe. A peak load may be prevented which might have generate cracks or otherwise damage the pipe.

In an embodiment of the pipe guiding device according to the invention, at least one of the guiding members is arranged adjustable with respect to the subframe in a direction transverse to the feed-through opening. In particular, the at least one of the guiding members is adjustable in a radial direction. Herewith, the feed-through opening can be easily adjusted to a varying size of a pipe. In particular, the feed-through opening can be adjusted for a pipe size of at least 100mm to at most 800mm, in particular to at most 400mm.

In an embodiment of the pipe guiding device according to the invention, the pipe guiding device is a bock. The bock is arranged for supporting and freely guiding a pipe. The subframe of the bock is rotationally connected to the mainframe of the bock. In particular, the subframe is freely rotatable about the axial axis of the feed-through opening with respect to the mainframe. The guidance by the bock is passive and the bock has no motor for driving a guiding member. The pipe guiding device according to the invention as a bock provides an advantage in that the bock permits both a friction reduced translation and a friction reduced rotation of the pipe. The bock may comprise a first roller bearing for supporting a

translational movement of a pipe and a second roller bearing for supporting a rotational movement of the pipe. In stead of a sliding friction, the roller bearings provide a roller friction during a movement of the pipe. Herewith, a friction in between the pipe and the bock is reduced.

In an embodiment of the pipe guiding device according to the invention, the bock has a subframe drive for driving the subframe in rotation about the axial axis with respect to the mainframe. Herewith, the bock can be used as a pipe rotation unit for driving the pipe in rotation about its longitudinal axis. The pipe can be rotated by the bock before starting a further translation of the pipe to steer the pipe in a desired direction. The bock with subframe drive can be positioned at a proximal end of the pipe for rotating the pipe.

In an embodiment according to the invention, the guiding member of the bock is arranged as a roller. The roller guides the pipe during a transport in an axial direction of the pipe and engages on an outer surface of the pipe. The roller rolls about a roller axis which roller axis is directed tangentially to the feed-trough opening. The roller advantageously reduces friction and may prevent damage to an outer surface of the pipe during a translation in the axial direction.

In a particular embodiment of the bock according to the invention, the roller as a guiding member has a diabolo shape. Advantageously, the diabolic shaped roller reduces friction in the axial direction and also encloses a received pipe in the feed-through opening. Advantageously, the pipe guiding device can be arranged with at most two diabolic shaped rollers as guiding members.

In an embodiment of the bock according to the invention, the subframe of the bock comprises an at least partially circumferential rim which rim is rotationally about the axial axis of the feed-through opening supported by the mainframe. Advantageously, the rim enables the subframe to rotate with respect to the mainframe. In an embodiment, the rim may be supported by a groove of the mainframe. The rim may be slidable mounted in the groove. Alternatively, the rim may be supported by a group of aligned roller elements connected to the mainframe to rotationally support the subframe with respect to the mainframe.

In a particular embodiment of the bock according to the invention, the rim of the subframe comprises a removable rim portion to create an opening for radially introducing a pipe into the subframe. After introducing the pipe into the subframe of the book, the rim can be enclosed around the pipe to allow a full rotation of the subframe with respect to the mainframe. Advantageously, a pipe can be easily received by the bock and a method for introducing a pipe into a subsurface can be performed more expedient.

In an embodiment of the pipe guiding device according to the invention, the pipe guiding device is arranged as a pipe pusher. The pipe pusher is arranged for exerting a thrust force onto a pipe for moving the pipe in axial direction. The pipe pusher can be used for pushing a pipe into the subsurface or for pulling a pipe out of the subsurface.

In an embodiment of the pipe pusher according to the invention, wherein the subframe of the pipe pusher is arranged freely rotatable with respect to the mainframe. Advantageously, the subframe can be rotated together with a pipe during an operation in a method for introducing, tensioning or retracting a pipe into or from a subsurface. This enables a method for introducing a pipe, wherein the pipe has to be rotated about a controlled angle to be directed in the subsurface. In an embodiment of the pipe pusher according to the invention, the subframe is drivable in rotation about the axial axis of the feed-through opening with respect to the main frame by a subframe drive. The pipe pusher comprises a subframe drive for driving the subframe in rotation. The subframe drive may rotationally connect the subframe to the mainframe. In particular, the subframe is rotationally connected to the mainframe, such that the subframe is swingable or can make a full rotation about the axial axis. The pipe pusher can be used to simultaneously rotate a pipe about its axial axis and thrust the pipe in the axial direction. Advantageously, besides as a thrust unit, the pipe pusher can also be used in a method for introducing a pipe into a subsurface as a drilling unit or a steering unit.

In an embodiment of the pipe was according to the invention, the subframe of the pipe pusher is tiltable with respect to the mainframe for positioning a pipe under a tilt angle with respect to a subsurface. The subframe is tiltable about a tilt axis which extends traverse to the axial axis in a substantially horizontal direction. Advantageously, a pipe can be introduced into the subsurface under the tilt angle. In particular, the tilt angle lies in between at least zero degrees and at most 40 °, in particular at most 30°, but preferably at most 20°. Advantageously, a pipe can be introduced into a subsurface from a position above the subsurface, in particular at ground level. The pipe pusher can be installed above the subsurface at ground level.

In an embodiment of the pipe pusher according to the invention, the subframe has a cylindrical shape which cylindrical shape has a longitudinal axis and comprises at both ends a bearing to connect the subframe to the mainframe. A pipe can be received inside the cylindrical shape of the subframe. The cylindrical shape means that the subframe has opposite parallel arranged walls which circumference the feed-through opening. The walls of the subframe may be open works walls, in particular a steelwork. In particular, the subframe comprises an outer framework which defines an inner space for guiding through a pipe. The outer framework has a feed-through opening at both ends for feeding through a pipe.

In an embodiment of the pipe pusher according to invention at least one of the guiding members is a thrust member for thrusting the pipe in an axial direction of the pipe to convey the pipe in axial direction through the feed-through opening. The at least one thrust member comprises a friction surface for, during operation, exerting a thrust in axial direction of the pipe onto the pipe to convey the pipe through the feed-through opening. The at least one thrust member is connected to a thrust drive for driving the trust member. In particular, the at least one endless conveyor member and thrust drive are configured for together exerting a thrust on the conveyor pipe of at least 500kN. In particular, the thrust drive can be activated for adjustably varying the speed and thrust of the endless conveyor members.

In an embodiment of the pipe pusher according to the invention, the at least one thrust member is an endless conveyor member. In particular, the pipe pusher comprises three thrust members. The thrust members comprise at least three endless conveyor members which are each arranged with a longitudinal part around the feed-through opening. Each endless conveyor member is being arranged drivable in rotation over at least two head rolls. The aforementioned longitudinal part of each endless conveyor member extends between the head rolls along the feed-through opening in a direction which is parallel to the axial direction of the pipe. In particular, the longitudinal parts of the endless conveyor members extend substantially in the horizontal direction at the side of the feed-through opening.

In an embodiment of the pipe pusher according to the invention, the endless conveyor members are formed by Caterpillar tracks. Alternatively, the endless conveyor members may be profiled rubber belts. Advantageously, the Caterpillar tracks or profiled rubber belts may provide sufficient grip onto the pipe to apply a thrust and transfer the pipe.

In particular, it may be advantageously to use the pipe guiding device according to the invention in a method, wherein a product pipe is introduced in a subsurface i.e. the ground or seabed. In particular, the method is a method for laying pipes in which the pipes are laid under a surface level, in which the pipes extend from a first point at surface level to a second point at surface level. In particular, the method is a method for laying cables, in which pipes are laid for introducing the cables.

The product pipe may be made from plastic or may have a vulnerable coated outer surface, which has to be protected from scratches and cracks. By using a pipe guiding device according to the invention in combination with such products pipes, rotational torques applied on the product pipe may be more equally distributed which may prevent cracks and the product pipe may be smoothly guided which may prevent further damages to the product pipe.

Further, the invention relates to a method for laying a pipe in a subsurface. After installation, the pipe extends substantially horizontal in between a first location and a second location at a surface level. In particular, the first location is a start or entry location, also called an introduction location and the second location is an end location, also called an exit location. A working area may be arranged at the first location and at the second location for installing equipment necessary to carry out the method.

The method comprises the step of providing a pipe guiding device according to the invention. The pipe is received in the feed-through opening of the pipe guiding device.

During operation, the pipe guiding device may hold the pipe in a substantially horizontal direction. In a step of the method, the pipe may be pushed into the subsurface by a pipe guiding device according to the invention arranged as a pipe pusher. In a step of the method, method, the pipe is being rotated about its longitudinal axis. Preferably, the pushing and the rotation of the pipe are carried out simultaneously by the pipe pusher. Advantageously, the rotation of the pipe is hardly hindered by the pipe guiding device according to the invention. The pipe guiding device strongly reduces counteracting frictional forces during a rotation of the pipe. The pipe guiding device arranged as a bock supports the pipe during rotation of the pipe and permits a movement in axial direction. The pipe guiding device arranged as a pipe pusher permits a rotation of a fed through pipe while the pipe is thrust in axial direction.

In an embodiment of the method according to the invention, the first location is an introduction location for introducing a pipe into the subsurface. The introduction location includes an entry point for introducing the pipe into the subsurface. A pit is provided at the introduction location. The entry point is positioned in the pit. The method comprises a step of filling the pit with a lubrication fluid. In particular, the lubrication fluid is a bentonite mixture, also called a bentonite slurry or bentonite based drilling fluid. The pit is filled until a filling level wherein the entry point is positioned under the filling level. The pit is filled to cover the entry point with lubrication fluid, such that during an introduction the lubrication fluid is introduced into the subsurface together with the pipe. Advantageously, the filled pit provides an efficient way to lubricate an introduction of a pipe. Additionally, the filled pit may make a seal at the entry point redundant. The filled pit takes over the function of the seal at the entry point, wherein returned lubrication fluid simply returns to the pit.

In this application, the filled pit at the introduction location is presented in combination with a method in which an introduced pipe is rotated. However, it may be advantageous to provide a filled pit with lubrication fluid also for another method for laying a pipe into a subsurface. This aspect of the filled pit taken is for that reason considered to be patentable as such.

In an embodiment, the method according to the invention comprises a step of anchoring the pipe guiding device, in particular the pipe pusher. The pipe guiding device may be positioned at ground level or in a pit. The pipe guiding device may be a pipe pusher for exerting a thrust force onto the pipe. To withstand counterforces, the pipe pusher can be fixated in position by anchoring the pipe pusher at ground level or by anchoring the pipe pusher inside the pit.

In an embodiment of the method according to the invention, the method for laying pipe in a borehole in the subsurface is a direct drill method. In the direct drill method, the pipe being laid is a product pipe. In particular, the product pipe is a cable casing. In the direct drill method, the borehole has an entry point and an exit point. The borehole runs between these two points along a drilling path through a subsurface. In particular the method is performed at land, in which the subsurface is soil. Alternatively, the method may be performed offshore, wherein the subsurface is a seabed. The product pipe has a proximal end and a distal end. The distal end, also called the front end, is provided with a rigid drill string. The rigid drill string is connected to the distal end of the product pipe. The rigid drill string comprises at least an angle piece, a measuring tube and a bit, in particular a drill bit. The borehole is created by the drill string along a planned drilling path.

In an embodiment, the angle piece is fixedly connected to the distal end of the product pipe. Herewith, the pipeline to be laid being fixedly connected to a(n) (angled-off) drill string. The angle piece is rigid in rotation connected to the distal end of the product pipe, such that the angle piece rotates together with the product pipe during operation. The angle piece may be an elongated piece and may have a tubular shape, in which the elongated piece is bended. The angle piece may be an angled front portion of the product pipe. The angle piece may be an angled coupling piece for coupling the bit under an angle to the distal end of the pipe product. The angle piece may be incorporated in the product pipe to obtain a steerable product pipe. Advantageously, by providing the angle piece, the bit may have a simple configuration. The bit may be a non-directional drill bit, also called a non-steerable boring device, because the product pipe may be steerable by the angle piece fixed to the product pipe.

In an alternative embodiment, the angle piece may be incorporated into the bit by providing a wedge shaped front portion at the front region of the bit. By pushing the product pipe in forwards direction, the wedge shaped portion of the bit steers the product pipe about a curved path. The bit moves the product pipe away from a straight line. By rotating the product pipe about its axial axis about a controlled angle, the wedge shape portion can be directed and the product pipe can be guided along a desired drilling path.

The measuring tube is present for determining a deviation from the desired drilling path. In case of a deviation, the proceeding of the product pipe can be corrected by rotating the product pipe.

In the direct drill method a drilling device is provided which comprises a thrust unit and a pipe rotation unit. The borehole is created by the drill string along the planned drilling path by the fact that a trust force from the drilling operation is exerted by the trust unit. The trust unit is also called a pipe pusher. The thrust force is transmitted via the product pipe to the drill string which includes the angle piece. The steering of the product pipe is carried out by the fact that the product pipe and the drill string which includes the angle piece are rotated together by the pipe rotation unit. By rotating the product pipe, the working direction of the bit is changed. The control of the bit, and thus the guidance of the product pipe, is achieved by rotation of the pipe (and thus of the drill string) by means of the drilling device.

The direct drill method is called "direct", because the product pipe is laid in the borehole simultaneously with the creation of the borehole. Advantageously, a preparing step in which a pilot borehole is created by a drill string is redundant and the drill method can be carried out in a relatively short timeframe. The product pipe directly follows the drill string through the borehole until the front end of the product pipe has reached the exit point of the borehole. After carrying out the direct drill method, the product pipe runs from the entry point of the borehole along the drilling path to the exit point of the borehole.

In an embodiment of the method according to the invention, the drill string comprises a drilling motor, wherein the drill bit is driven by the drilling motor. The drilling motor may acquire its drive energy from a drilling fluid fed through the product pipe. In particular the drilling fluid is fed through the measuring tube and the angle piece. The drilling fluid may be fed to the drilling motor through a separate feed line which runs inside the product pipe. Soil present along the drilling path is loosened by the drill bit and may be discharged from the borehole via an annular space around the product pipe by this drilling fluid exiting the drill bit. A continuous flushing may be obtained through the annular space. In comparison with the known direct pipe method, the direct drill method is advantageous in that the direct drill method has no power supply and no steering cables which extend to the drill bit. In the direct drill method according to the invention a necessary power for proceeding and steering the product pipe is generated outside the borehole by means of the thrust unit and pipe rotation unit. Advantageously, herewith the direct drill method is suitable to be carried out for pipe products having a relatively small diameter of at most 400 millimetres, in particular at most 300 millimetres, preferably at most 200 millimetres.

In an embodiment of the method according to the invention, the bit has an outer contour which is at least 10 percent, in particular at least 20 percent, but preferably at least 35 percent bigger than an outer diameter of the laid product pipe. The bit provides an overcut with respect to the product pipe. The dimensions of the outer contour of the bit with respect to the maximum outer diameter of the product pipe determine the dimensions of the annular space around the product pipe in the borehole. The dimensions of the annular space are important to provide a through flow of drilling fluid to the proximal end of the product pipe.

In an embodiment of the method according to the invention, the drill bit and the drilling motor are connected by a gear mechanism. The gear mechanism is provided in between the drill bit and a thrilling motor. The gear mechanism may be mounted to the angle piece by a gear mounting.

In an embodiment of the method according to the invention, the drill bit is an excavating bit for excavating through the subsurface. The excavating bit has stationary components. The excavating bit is a stationary bit. The excavating bit has for example at least one flushing nozzle for flushing away surrounding soil. The excavating bit is in particular advantageous for soft soil. Advantageously, the excavating bit may have a relatively small configuration which allows the introduction of pipe products having a small diameter of at most 300 millimetres, preferably at most 200 millimetres.

In an embodiment of the method according to the invention, the drill string may comprise a measuring tube including a measuring probe for transmitting the measurement data to the control station on the ground surface via a cable running inside the product pipe. Alternatively, the measuring probe may transmit the measurement data wirelessly to the contour station on the ground surface. Advantageously, the wireless transmitting of the measurement data further allows the laying of relatively small product pipes.

In an embodiment of the method according to invention the product pipe is prepared in one piece on the ground surface prior to commencement of the laying. The laid tired may be a oil gas pipeline, in particular an oil gas pipeline having a small diameter of at most 300 millimetres. Advantageously, the product pipe can be tested on leakages before the introduction into the subsurface.

In an embodiment of the method according to the invention, the product pipe comprises at least two individual pieces. The product pipe comprises at least two product pipe segments. By providing product pipe segments, the direct drill method is carried out in several steps. At the start of the drilling, the first product pipe segment is attached to the drill string. In a first step, the first product pipe segment is introduced into the subsurface. After introduction of the first product pipe segment into the subsurface, and after its length has been drilled out, the second product pipe segment is attached in a next step to the first product pipe segment before continuing the drilling operation in a subsequent step. The product pipe is assembled by connecting a product pipe segment to a proximal end of an already introduced product pipe segment by a joint station. The joint station may be positioned at the introduction location. The joint station may be a welding station. So, the introduction of the product pipe is regularly interrupted for coupling the second or a further product pipe segment to the proximal end of the first product pipe segment. The use of product pipe segments provides the advantage that a necessary working area may remain relatively small. The product pipe segments can be stacked and stored at the working area. A crane may be used to lift the product pipe segments and bring the product pipe segments together to carry out a coupling by the joint station at the introduction location.

In particular, the product pipe comprises at least two product pipe segments having each a substantially equal length. The product pipe may comprise three product pipe segments in which each product pipe segment has a length of about one third of a total length of the product pipe. In particular, the product pipe segment has a length of at least 50 metres, but preferably at least 100 metres. Preferably, the product pipe is a pipe casing for housing cables. The pipe casing is suitable to be segmented, because the pipe casing needs no pressure testing. It is a remarked that the direct drill method differs in several ways from known drilling methods. In the first place, the combination of the above-described features is fulfilled by none of the existing methods for trenchless laying of pipelines in boreholes. This applies both to the direct pipe method and to the known HDD method.

The method is differentiated from the direct pipe method (DP) inter alia by the fact that the structure, control and powering of the drill string are of substantially simpler construction. The DP method essentially utilizes the drill strings which are known from microtunneling or from controlled pipe jacking, where the drive of the drill bit is realized via hydraulic motors and the control of the drill head via hydraulic cylinders. These structural parts are relatively sensitive and complicated in terms of their control. Moreover, they have to be connected to a suitable hydraulic circuit (pressure-volume requirements), i.e. either the hydraulic power unit is located directly in the drill string (larger diameter of the pipeline necessary, at least about 800 mm), or it is supplied from above ground by corresponding tube connections (length limited to about 80 - 250 m). Both variants are prone to faults and are complicated in structure and operation.

The method according to the invention is further differentiated from the DP method (as well as the HDD method) by the rotatable mounting of the pipe on the ground surface, whereby the pipeline can be utilized not only for the power transmission for the drilling operation but also for the control of the drill string.

A further important distinguishing feature in relation to the DP method relates to the fact that, with the method according to the invention, diameter-length combinations which cannot be covered by the DP method (small pipe diameters, large bore lengths) can be laid.

The method according to the invention is thus differentiated from the DP technique in particular with respect to the laying lengths and pipe diameters, as well as the control of the drill string. The basic advantages of the invention are environmental friendliness (small space requirement, only one work space); speed (only one work cycle); economy (low investment in machinery and equipment); safety (permanent borehole support); robustness (utilization of proven and simply constructed individual components).

Further preferred embodiments are defined in the subclaims.

The invention will be explained in more detail with reference to the appended drawings. The drawings show a practical embodiment according to the invention, which may not be interpreted as limiting the scope of the invention. Specific features may also be considered apart from the shown embodiment and may be taken into account in a broader context as a delimiting feature, not only for the shown embodiment but as a common feature for all embodiments falling within the scope of the appended claims, in which: Fig. 1 a shows in a front view a pipe guiding device according to the invention arranged as a bock for supporting a pipe;

Fig. 1 b shows the bock of figure 1 a in a cross-sectional top view about a line A-A; Fig. 1c shows the pipe guiding device of figure 1 a in a cross-sectional side view; Fig. 2a-2c show a pipe guiding device according to the invention arranged as a pipe pusher for exerting a thrust onto a pipe;

Fig. 3 shows in a schematic view a method for introducing a pipe into a subsurface, including a pipe pusher with an incorporated rotation unit according to the invention; Fig. 4 shows in a schematic view the method as in Fig. 3, including a separate pipe pusher and a separate pipe rotation unit which is positioned at a pipe end;

Fig. 5: shows an illustrative representation of the drill string for small pipes (up to about 300 mm diameter),

Fig. 6: shows an illustrative representation of the drill string for larger pipes (larger than about 300 mm diameter),

Identical reference numbers are used in the drawings to identify identical or similar components.

Figure 1 a shows in a front view a pipe guiding device according to the invention. The pipe guiding device is arranged as a bock 22 for supporting a pipe 10. The bock 22 is a component of a drilling equipment for drilling a pipeline into a sub surface. The bock 22 is a passive component. The bock has no internal drive and only supports and guides a pipe.

The pipe guiding device comprises a mainframe 29. The mainframe is a steelwork. The mainframe 29 provides a ground support and has at least one mainframe feet 291 at a lower region of the mainframe 29 for positioning the mainframe on a surface i.e. the ground. Normally, the bock 22 is placed at ground level. The mainframe may comprise at least one anchoring member for anchoring the mainframe to a working area surface.

Further, the bock 22 comprises a subframe 30. The subframe has a cylindrical outer contour. The subframe 30 has a circular outer rim 33. The outer rim 33 completely circumferences the subframe 30. The subframe 30 is supported by the mainframe 29. The mainframe 29 has a bearing 292 for supporting the subframe 30. The bearing 292 is shaped as a groove. The bearing 292 is open in upwards direction for receiving the subframe. The subframe 30 can be lowered from above into the bearing 292. The circular outer rim 33 of the subframe 30 is received in the bearing 292. The circular outer rim 33 is slidable with respect to the bearing 292. Herewith, the subframe 29 is slidable mounted to the mainframe 29. The subframe 30 is mounted rotationally about an axial axis L with respect to the mainframe 29. The subframe 30 is mounted to the mainframe, such that the subframe 30 is rotatable with respect to the mainframe 29. In an embodiment of the bock 22, the outer rim 33 may have a removable rim portion to create an opening in the rim for radially introducing a pipe.

The subframe 30 of the bock 22 comprises at least two guiding members 32 for guiding a pipe 10. The at least two guiding members are mounted by a frame portion 31 to the outer rim 33. The at least two guiding members 32 are arranged to engage onto an outer surface of a pipe 10. The at least two guiding members 32 are positioned opposite each other for enclosing a pipe. The at least two guiding members 32 form together a feed- through opening 301 for receiving a pipe 10. The feed-through opening has a diameter of at least 50mm and at most 800mm, in particular, the feed-through opening has a diameter of at least 100mm at most 400mm. The feed-through opening defines the axial axis L. The axial axis is a centre axis which coincidences with a longitudinal axis of a fed through pipe.

The at least two guiding members 32 are equally spaced around the feet-through opening. In particular, the subframe 30, also called a roller bock swivel plate, comprises in particular three, but preferably four guiding members 32 to obtain a substantially equal distribution of a load of a pipe 10 over the guiding members. The roller bock swivel plate comprises roller mountings 31 for holding the rollers. Here, the guiding member 32 is a roller. The roller provides a roller friction instead of a sliding friction in between the roller and the pipe. The roller has a longitudinal roller axis which extends in a tangential direction with respect to the feed-through opening. The roller rolls about the roller axis. As shown, the roller is cylindrically shaped and has a constant diameter. Alternatively, the roller may have a cylindrical shape with a varying diameter, in particular including a reduced diameter at a centre region of the roller for enclosing a pipe. Preferably, the roller has a shape of a diabolo for partly enclosing a pipe. The guiding member may have an outer coverage of a soft material to prevent scratches or other damages to the pipe.

Figure 1 b shows in a cross-sectional view the bock 22 of figure 1 a about a cross- sectional line A-A. A pipe 10 is received in the feed-through opening 301 of the bock 22. The pipe 10 has a longitudinal pipe axis which coincidences with the axial axis L of the feed- through opening 301. The guiding member 32 engage to the pipe 10 to support and position the pipe. Further, figure 1 b shows the outer rim 33 which is captured in the groove shaped bearing 292. The enclosure of the outer rim 33 in the bearing 292 prevents a translational movement of the subframe in axial direction, but permits a rotational movement about the axial axis L of the subframe with respect to the mainframe 29. Herewith, the bock 22 is arranged to support and guide a substantially horizontal pipe 10.

Figure 1 c shows in a cross-sectional side view the bock 22 of figure 1 a from a side indicated by arrow B. The pipe 10 is received in the feed-through opening 301 of the bock 22. The pipe 10 is fully enclosed by the subframe 30 and surrounded by the guiding members 32. Fig. 1 a-c represent by way of example an embodiment of a roller bock 22, which permits both axial movements of the pipe 10 and rotary movements of the pipe 10. The invention provides a device, wherein the product pipe 10, on the ground surface 19, can be mounted on a roller bock 22 such that axial movement and rotation of the product pipe 10 in the roller bock 22 can be executed at the same time. The pipe 10 is here mounted on rollers 32, which are supported on the roller bock swivel plate 30 by roller mountings 31. This roller bock swivel plate 30 is mounted rotatably within the roller bock frame 29. The rollers 32 thus allow the translatory movement of the pipe 10 through the roller bock 22, whilst the roller block swivel plate 30 enables rotation of the pipe 10.

Figure 2a-c show an alternative embodiment of the pipe guiding device according to the invention, in which the pipe guiding device is arranged as a pipe pusher 14. The pipe pusher 14 is arranged for exerting a thrust force in an axial direction onto a pipe 10. The pipe pusher 14 is arranged for pushing or pulling a pipe in a substantially horizontal position in or out of a subsurface. The pipe pusher 14 is usable in a drilling method for introducing a pipe, like HDD (horizontal directional drilling). In particular, the pipe pusher 14 is suitable for use in a method of direct drilling, wherein the pipe has to be rotated for steering the pipe through the subsurface.

Figure 2a shows in a perspective view a pipe pusher 14 which comprises a mainframe 29 and a subframe 30. The subframe 30 is rotatably mounted with respect to the mainframe 29. Figure 2b shows the pipe pusher 14 in a front view. Figure 2c shows the pipe pusher 14 in a top view.

The mainframe 29 is a steelwork, which comprises at a lower region a platform 291 for positioning the mainframe. The platform is build of welded l-profiles. The platform provides a flat surface for positioning the mainframe at a ground surface. The platform may comprise adjustable mainframe feet to align the pipe pusher with a pipe or to tilt the pipe pusher with respect to the ground surface to introduce a pipe into the subsurface under an inclination defined by a tilt angle. Similarly, the mainframe may comprise a top-mainframe part and a bottom mainframe part, which top-mainframe part can pivot with respect to the bottom-mainframe part.

Further, the mainframe has two upstanding wall elements 293. The wall elements are positioned opposite each other. Each wall element houses a bearing 292. The opposite positioned bearings 292 define a centre line which in operation coincidences with a longitudinal, axial axis of a received pipe 10 in the pipe pusher. The centre line extends in a length direction of the pipe pusher. The upstanding walls are shored by several beams which are positioned around the upstanding walls and mounted to the platform.

The subframe 30 is positioned in between the wall elements. The subframe is rotationally about the axial axis connected to the mainframe 29. The subframe is supported at both ends by a front and rear bearing 292 of the mainframe 29. The subframe 30 extends in a substantially horizontal position. The subframe is mounted to the mainframe, such that the subframe is able to make a swingable rotation about at least 180°, in particular about at least 270°, but more in particular to make a full rotation about its longitudinal axis with respect to the mainframe.

The subframe 30 is cylindrically shaped, in particular the subframe is box-shaped. The subframe has an outer framework. The outer framework is build by welded steel profiles. The outer framework 301 delimits an inner space. At both ends, the subframe 30 has a feed- trough opening 302 for feeding a pipe through the inner space of the subframe. The outer framework 301 houses at least two guiding members 32. Here, the pipe pusher 14 comprises four guiding members 32. The guiding members 32 are equally spaced around the feed- through opening. The guiding members 32 delimit the size of the feed-through opening. The guiding members 32 are positioned in the inner space of the subframe 30. The at least two guiding members 32 are arranged for engaging a pipe and exerting a thrust force onto the pipe 10.

At least one of the guiding members 32 is a thrust member for exerting a thrust force onto a pipe 10. The thrust member is an active component and driven by a thrust drive 322 for operating the thrust member. Remaining guiding members of the pipe pusher may be a passive component as a support member and may be arranged to maintain a pipe in engagement with the thrust member. The passive guiding members may be arranged to clamp the pipe to the active thrust member.

As shown, the at least one thrust member 32 is an endless conveyor member 321. The endless conveyor member 321 has a longitudinal part for engaging a pipe. The longitudinal part of the endless conveyor member is tangentially positioned at the feed- through opening and extends in an axial direction. The endless conveyor member 321 extends in between two head rolls. The thrust drive 322 is connected to a head roll for driving the endless conveyor member 32 for exerting a pushing or pulling force on a pipe.

The guiding members 32 are arranged adjustable in a radial direction to adjust a size of the feed-through opening. By changing a size of the feed-through opening, the pipe pusher can be adapted to a smaller or bigger pipe diameter. The feed-through opening is for example adjustable from at least 50mm to at most 400mm. The guiding members 32 are pivotally positioned with respect to the outer framework 301 and can pivot to and fro the centre line. At least one guiding member actuator, here a hydraulic cylinder, is provided for acting the guiding member.

Fig. 2a shows a pipe pusher including a freely rotatable subframe. The subframe may freely rotate together with a fed pipe. Fig. 2c shows a pipe pusher including a rotational drivable subframe. The subframe is drivable in rotation with respect to the mainframe by a subframe drive 294 for exerting a rotational torque onto a pipe. Herewith, the pipe pusher is able to apply both a thrust force for moving a pipe about its longitunal axis and a rotational torque onto a pipe for rotating the pipe about its longitudinal axis. The invention relates to a device for use in a drilling method for laying a pipe in a subsurface, in particular for a direct drill method, wherein a thrust unit and a pipe rotation unit are mounted in a drilling device such that axial movement and rotation of the product pipe can be executed at the same time. Advantageously, the thrust force and rotational torque can be applied simultaneously.

In Fig. 3, the elements of a direct drill method are represented by way of example with its mechanical devices. A pipe or so called pipeline 10, in particular a product pipe, prepared on the ground surface 19 is here pushed by a drilling device 13 along a planned drilling path 4 from an entry point 2 to an exit point 3. The soil 16, the subsurface, present along the drilling path 4 is loosened by a bit 6, in particular a drill bit. The drill bit 6 is here driven by a drilling motor 7, which acquires its energy from a flowing drilling fluid 17, in particular a drilling mud. This drilling fluid 17 is pumped by a pump 27 through a tube 28, a rotary feed-through 12, a cable conduit 1 1 , the pipe 10, and a measuring tube 9 and an angle piece 8. The measuring probe 21 disposed in the measuring tube 9 transmits the position data, via a cable 25 running inside the pipe 10, to the control station 26 on the ground surface 19. The soil 16 loosened by the drill bit 6 is transported by the drilling fluid 17, which enters at the drill bit 6 into the borehole 1 , through the annular space 18 to the entry point 2. The feed forces necessary for the drilling operation are generated by the drilling device 13 and transmitted to the pipe 10 via the thrust unit 14 disposed in the drilling device 13. For the steering of the drill bit 6 along the drilling path 4, it is necessary to change the working direction of the drill bit 6. This is done by small rotary movements of the pipe 10, executed by the pipe rotation unit 15 within the drilling device 13. The rotary movements of the pipe 10 are here

transmitted to the drill string 5 which is fixedly connected to the pipe 10 and in which the angle piece 8 is disposed. Attached to the end of the pipe is the cable conduit 1 1 , from which the cable is led out of the pipe 10 without discharge of the drilling fluid. The connection between the pipe 10 and the tube 28 is realized via the rotary feed-through 12. In Fig. 4, the structure of the method is once again shown in basic representation

(analogously to Fig. 3) with its mechanical devices. As a further advantageous construction, a two-part embodiment of the drilling device 13 is here represented however, wherein the thrust unit 14 is again constructed close to the entry point 2, whilst the pipe rotation unit 15 is installed on the end of the pipe 10 (between the cable conduit 11 and the rotary feed- through 12). Whilst one part of the drilling device 13 comprising the thrust unit 14 is fixedly configured and exerts a thrust force during operation, the other part of the drilling device 13 comprising the pipe rotation unit 15 for exerting a torque to the pipe moves free in translation translation with the pipe 10during a laying works. The thrust unit 14 is a pipe guiding device according to the invention and can be considered as a pipe pusher having a freely rotatable subframe for permitting a free rotation of a pipe. The pipe rotation unit 15 is a pipe guiding device according to the invention and can be considered as a bock 22 which bock includes a subframe drive for driving a pipe in a rotation direction. As a result of this separation, the simultaneous transmission of thrust forces and torques to the pipe 10 can be realized in a structurally particularly simple manner. The invention provides a device, wherein the drilling device comprises two parts, wherein the thrust unit 14 is installed close to the entry point 2 and the pipe rotation unit 15 is installed on the end of the product pipe 10.

In Fig. 5, a drill string for smaller pipes (up to about 300 mm diameter) is illustrated by way of example. The drill bit 6 is located on the front end of the drill string 5, which loosens the soil 16 present along the drilling path 4 in a substantially mechanical manner, supported by the drilling fluid 17 discharged at the drill bit 6. This drilling fluid 17 takes up the loosened soil 16 and transports it through the annular space 18 through the borehole 1. The drill bit 6 is driven by the drilling motor 7, which draws its energy from the drilling fluid 17 flowing through it. The drilling motor 7 is fixedly connected to an angle piece 8. Depending on the drilling radius of the provided drilling path 4, this angle piece 8 has an angular deviation of at least 0.5° to at most 2.5°. By rotation of the drill string 5 (and thus of the angle piece 8), the working direction of the drill bit 6 is changed and thus enabling a steering of the drill string 5. Behind the angle piece 8 is adjoined the measuring tube 9, in which the measuring probe 21 is positioned. In a preferred embodiment, the measuring probe 21 is provided by a device for determining the respective position of the drill string 5 in the soil 16, which device is known from the HDD method (HDD = Horizontal Directional Drilling). The measuring method of this measuring probe can use as reference parameters both the magnetic field and gravitational field of the Earth, but it can also be based on the measuring principle of a gyrocompass. Similarly, it is possible for the measuring probe to be based on the receiver principle, as is likewise known from the HDD industry. The invention provides a device, wherein the measuring probe 21 is disposed within the gear mounting 24 and outside the drilling motor 7. In Fig. 6, a drill string 5 for larger pipes (larger than about 300 mm diameter) is represented. In this case, the torques of commercially available drilling motors 7 are sometimes insufficient to drive the drill bit 6 (for example in rock drillings), so that between the drilling motor 7 and the drill bit 6 is provided a gear mechanism 23, which reduces the rotation speed of the drilling motor 7 and simultaneously increases the torque available to drive the drill bit 6. The gear mechanism 23 is connected to the angle piece 8 by a gear mounting 24, so as to be able to absorb the generated torques in the gear mechanism 23. In a preferred embodiment, the measuring probe 21 is integrated into the gear mounting 24, whereby the spatial distance to the drill bit 6 is reduced and the measuring accuracy of the position determination of the drill bit 6 is increased. The drilling fluid 17 is here fed to the drilling motor 7 via a feed line 20 running inside the pipe 10. The transmission of the measurement data of the measuring probe 21 is realized analogously to the corresponding description with respect to Fig. 5. The measurement data of the measuring probe 21 can once again be transmitted via a cable connection 25.

Numerous variants are possible in addition to the embodiment shown. The bock of figure 1 may for example comprise a subframe drive for driving the subframe in rotation about the axial axis. Herewith, the bock may serve as a pipe rotation unit.

Although the invention has been disclosed with reference to particular embodiments, from reading this description those of skilled in the art may appreciate a change or modification that may be possible from a technical point of view but which do not depart from the scope of the invention as described above and protected by the claims hereafter.

Modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. It will be understood by those of skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. Therefore, it is intended that the invention is not limited to the particular embodiments disclosed in the above detailed description, but that the legal protection of the invention will include all embodiments falling within the scope of the appended claims.

Reference symbol list

1 borehole 22 roller bock

2 entry point 23 gear mechanism

3 exit point 24 gear mounting

4 drilling path 25 cable

5 drill string 26 control station

6 drill bit 27 pump

7 drilling motor 28 tube

8 angle piece 29 main frame

9 measuring tube 291 platform

10 pipe 292 bearing

11 cable conduit 293 wall element

12 rotary feed-through 30 subframe

13 drilling device 301 outer framework

14 thrust unit 302 feed trough opening

15 pipe rotation unit 31 roller mounting

16 subsurface 32 rollers

17 drilling fluid 321 conveyor member

18 annular space 322 thrust drive

19 ground surface 33 outer rim

20 feed line 294 subframe drive

21 measuring probe L axial axis