EP1083297A2

EP1083297A2 - Apparatus for freeing an object underground, and the application of such apparatus

Info

Publication number: EP1083297A2
Application number: EP00203119A
Authority: EP
Inventors: Teunis Visser
Original assignee: 3-D Drilling BV
Current assignee: 3-D Drilling BV
Priority date: 1999-09-10
Filing date: 2000-09-11
Publication date: 2001-03-14
Also published as: NL1013025C2; EP1083297A3

Abstract

The invention relates to a method for freeing an object underground, such as a pipe or a drilling rod used for horizontal drilling. The apparatus according to the invention comprises a body (1) having an opening for receiving the object (A) to be freed. The body is provided in the circumferential direction of object (A) with soil material-loosening means (3). These soil material-loosening means (3) are for example nozzles through which an aqueous solution is spurted.

Description

The present invention relates to an apparatus for freeing an object underground, said object being oblong and having a substantially constant cross section.
Soil is becoming ever more important for infrastructure, such as pipelines. When laying, maintaining or removal of this infrastructure it is often important that the daily routine aboveground is not disturbed. This has led to the development of the technique of guided horizontal drilling.
Whereas the expertise of installing infrastructure has developed strongly, the know-how in freeing an object underground, for example for its removal or maintenance, is badly underdeveloped. For the removal of cables a street has to be laid open and because of the resulting inconvenience and cost this is often left undone. The result is that difficulties arise when other underground infrastructure has to be installed.
The object of the present invention is to eliminate this problem.
To this end, the present invention provides an apparatus characterized in that the apparatus comprises a body having an opening for receiving the oblong object such that the body and the object can move in relation to each other in the longitudinal direction of the object, the body surrounds the object when in a received position over an angle of at least 190°, the body is provided in the circumferential direction of the element with soil material-loosening means, as well as with means for moving the body in the longitudinal direction of the object.
Such an apparatus may be slid over one end of the longitudinal object and may free the object by moving the apparatus over the length of the element. Thus it is possible using the apparatus according to the invention to free objects in the soil for their maintenance or removal.
The means for moving in the longitudinal direction are, for example, a motor or a rod.
For good guidance, the body surrounds the element in a received condition over an angle of at least 270°, preferably 360°.
This method will ensure that the entire surface of the element that may be adhering to the soil, is freed.
Preferably the body comprises a conduit for supplying a liquid and the means for loosening soil material are soil material-loosening means propelled by the liquid.
Such soil material-loosening means may for example be drilling or milling means which are driven according to the principle of a hydromotor.
According to an alternative embodiment the body comprises a conduit for supplying a liquid, and the soil material-loosening means are nozzles through which the liquid can be spurted.
The advantage of this embodiment is that the body does not have any moving parts which could wear quickly or break under the severe underground conditions.
For moving the apparatus in the longitudinal direction, the means are preferably a bar. With bar it is possible to make a movement of pushing as well as a pulling movement.
A further advantage of a bar is that is may comprise a duct for supplying the liquid used for the soil material-loosening means.
A big problem with horizontal drilling is that the drilling rods can get stuck underground. This happens in particlular, but not solely, when the connected drilling rods have to curve. When this happens, the drilling rods, which are fairly costly, are lost.
According to an important embodiment of the apparatus according to the invention, the same is used for freeing stuck drilling rods. Not only are the drilling rods retrieved, but also the drilled hole is not lost and a considerable loss of time is avoided.
Another application of the invention is freeing a conduit in the broadest sense, and in particular the conduit is a waterpipe, a power cable, a gaspipe, a datacommunication line or a pipe sleeve for such conduits or pipes.
In this way the space available underground is not occupied by redundant, broken or obsolete conduits.
The present invention will now be elucidated with reference to the drawing, in which Fig. 1 represents a cross-sectional view of an apparatus according to the invention surrounding an underground conduit;
Fig. 2 represents a partial side-elevation of the apparatus depicted in Fig. 1;
Fig. 3 represents a frontal view of the apparatus depicted in Fig. 1.
In Fig. 1 the tube to be freed is designated by A and the soil surrounding the tube A by reference numeral B. The tube A is surrounded by a bush-like body 1 of the apparatus, which body 1 is provided with a bar 2 for moving the bush-like body 1 in the longitudinal direction of the tube A. The bar 2 is hollow and acts as a supply dust for a liquid C which is used for freeing the tube A. In the embodiment shown, the bush-like body 1 is provided with nozzles 3, 3' through which the liquid C is forced with great force.
The body 1 may surround the tube A completely, in which case the apparatus is slid over one end of the tube A. Alternatively, the body 1 may consist of parts capable of moving in relation to each other, for example two hinged parts. This makes it possible to surround the conduit over at least 190° without this having to be done at an end of the object to be freed, such as the tube A.
It is evident for the person skilled in the art that the number of nozzles 3, the flow rate of the liquid C and the force with which the liquid C is forced through the nozzles depends on the condition of the soil and the speed with which it is desired to move the bush-like body 1 along the tube A. This can easily be established by experiment, wherein increasing the number of nozzles or increasing the pressure and the flow rate is beneficial if the object is not freed or is not freed with the desired speed.
For freeing an object, nozzles may as a rule of thumb be placed every 10 cm over the circumference of the bush-like body 1, which nozzles are substantially axially oriented. When the apparatus is pushed by bar 2 (and that is most often the case) the nozzles 3 will be placed at the front side of the bush-like body 1. When pulling bar 2, nozzles 3 will be placed at the rear end of the bush-like body 1, that is the same end as where bar 2 is attached. The bush-like body 1 may be provided with a bevel 4, which reduces the immediate frontal surface and prevents that stones etc. get jammed between the body and the tube A. After all, this could result in wear of the wall of the tube.
For a proper guidance of the bush-like body 1 over bulges of the tube A, such as welding seams or joins between coupling pieces, the bush-like body 1 is preferably provided with a guiding element 5, which guiding element 5 is located more distally from the bevel 4 and is arranged such that when the guiding element 5 encounters a barrier on the surface of tube A, the guiding element 5 is moved away from tube A as a result of which the bevel 4 can pass the barrier without being caught. The guiding element 5 is, for example, a radial fin which is directed in the longitudinal direction of the bush-like body 1, the fin having a V-shape distally or the shape of a semi-circle. According to an especially advantageous embodiment, the guiding element 5 is formed as the shape of a convex surface, such as a bullet or a segment of a sphere thereof (Fig. 2). The advantage being that damage of the guiding element 5, for example from stones, is greatly reduced. The body 1 may be provided with one guiding element 5, which during use is located preferably at the upper side of the tube A, but preferably the apparatus is provided with a plurality of guiding elements 5, preferably at least three, which are distributed in the circumferential direction of tube A over the bush-like body 1. The guiding element 5 may also be formed by the nozzles 3. According to another embodiment the guiding element is a flexible rubber gasket. This is a simple manner of preventing that stones etc. end up between the body 1 and the tube A.
The present invention can be used for various purposes. An important application is the removal of objects, such as old or obsolete conduits and drilling rods that have become stuck. In addition,the invention may be used for maintenance work, such as freeing a drainage conduit in order to unclog pores or holes therein. To this end, the apparatus will preferably be provided with one or more nozzles which are directed to the outside of the drainage tube. These nozzles directed towards the tube A do not need to be at the front or rear end. For example, the wall of the body 1 facing the tube A may be provided with nozzles (not shown). In such a case the liquid is preferably clean water.
It is remarked that under normal circumstances, the liquid will often be a drilling liquid, such as a bentonite suspension. This has a lubricating action.
As a further application it is contemplated for the apparatus to be provided with an apparatus for applying a coating, such as a water-resistent coating, or with a reel containing tubular film which is rolled up onto itself, with which a tube A may be provided by a sleeve of film.

Claims

Apparatus suitable for freeing an object underground, which object is oblong and having a substantially constant diameter, characterized in that the apparatus comprises a body having an opening for receiving the oblong object such that the body and the object can move in relation to each other in the longitudinal direction of the object, the body surrounds the object when in a received position over an angle of at least 190°, the body is provided in the circumferential direction of the element with soil material-loosening means, as well as with means for moving the body in the longitudinal direction of the object.
Apparatus according to claim 1, characterized in that the body surrounds the element in a received situation over an angle of at least 270° and preferably 360°.
Apparatus according to claim 1 or 2, characterized in that the body comprises a conduit for supplying a liquid and the soil material-loosening materials are soil material-loosening means propelled by the liquid.
Apparatus according to claim 1 or 2, characterized in that the body comprises a conduit for supplying a liquid and the soil material-loosening means are nozzles through which the liquid can be spurted.
Apparatus according to any of the preceeding claims, characterized in that the means for moving the body in the longitudinal direction of the object is formed by a bar.
Apparatus according to claim 5, characterized in that the bar has a duct for supplying the liquid.
Apparatus according to any of the preceeding claims, characterized in that the body is provided with a guiding element.
Application of the apparatus according to any of the preceeding claims for freeing stuck drilling rods.
Use of an apparatus according to the claims 1 to 7 for freeing a conduit.
Use according to claim 8 or 9, characterized in that the conduit is a waterpipe, a power cable, a gaspipe, a datacommunication line or a pipe sleeve for such conduits or pipes.