WO1991005132A1

WO1991005132A1 - Reamer

Info

Publication number: WO1991005132A1
Application number: PCT/SE1990/000612
Authority: WO
Inventors: Gunnar Jonsson; Anders ODÉN; Leo HOLMSTÉN
Original assignee: Diamant Boart Craelius Ab
Priority date: 1989-09-29
Filing date: 1990-09-25
Publication date: 1991-04-18
Also published as: SE8903212L; SE8903212D0; AU6507290A

Abstract

A device for reaming an elongated hole formed in the ground and for transporting an elongated element through the reamed hole, comprising a reaming portion (2) provided with means (4) for connection with a rotating element (A), and a transport portion (3) which is pivotally connected with the reaming portion and provided with means (18 - 20) for connection with the elongated element (B). The connection between the two portions (2, 3) comprises a joint (13, 14) making possible the relative pivoting of said portions in all directions.

Description

REAMER 1

DESCRIPTION

Technical field

The present invention relates to a device for reaming an elongated hole formed in the ground and for transporting a elongated element through the reamed hole, comprising a reaming portion provided with means for connection with a rotating element, and a transport portion which is pivotally connected with the reaming portion and provided with^"- means for connection with the elongated element.

The device is particularly intended to be detachably connected on the ground surface with a rotatable drill string for being pulled back by the latter through the elongated, approximately horizontal hole formed by a drill head which has previously been detachably connected with the drilling rod.

Prior art

Devices of the above-mentioned kind are previously known. However, they exhibit one or several of the following disadvantages. One obvious disadvantage is the great distance between the reaming portion and the transport portion, implying that, for example, stones of some size can enter between said portions thereby preventing the pulling of the device through the hole or at least making it more difficult. Another disadvantage is that the two portions cannot be pivoted in all directions relative to each other, implying' that the portions, the connecting joint between same and/or the. drill string will be subject to breaking stresses, which could cause damage to these pieces. A further disadvantage is that the connecting joint is of a weak structure and is unprotected against physical shock and penetration by particles, which could cause rupture or could impair the pivotal function of the portions. Yet another disadvantage is that it is difficult and time-consuming to connect the elongated element, which has to be pulled back through the hole, to or from the transport portion, and, further, said connection must be established or released by means of a wrench.

An example of a previously known device exhibiting most of the above-mentioned disadvantages is the device shown in Fig. 6 of EP-A2-0209217.

Summary of the invention

It is an object of the present invention to eliminate the above described disadvantages cf previously known devices and to provide a device whose reaming and transport portions are pivotable in all directions relative to each other and are spaced apart by a minimum distance, and whose joint connecting the two portions is of a sturdy and protected construction, the device further being provided with means which are actuable such that the elongated element may be simply and quickly detachably connected with or disconnected from the transport portion without using a wrench.

This and other objects of the invention will be achieved by the device according to same having the features stated in the characterizing portions of the claims.

Description of the figure

The sole figure of the drawing is a side view of a device according to the invention showing the lower half of the figure in section.

Preferred embodiment

The device 1 shown in the figure is intended to be connected to a drill string A and a hose B. The drill string A is made up of a number of interconnected pipes and is rotated and displaced in a hole in the ground by a machine standing on the ground. The hole is formed by inserting a drill head in the ground and thereafter orienting and displacing same in a substantially horizontal direction before orienting it in a more vertical direction when it will exit from the ground, the drill head being detachably connected with the drill string A, through which it is supplied with pressurized fluid. The drill head is then removed from the drill string A and the device 1 is connected with same and with the hose B. The drill string is then pulled back through the hole under rotation for reaming the latter and for pulling the hose through the hole. When the hose has been pulled through the -entire previously formed hole, conduits of the desired kind may be pulled through the hose defining the walls of the hole. Obviously, some other elongated element may be pulled back through the hole instead of a hose B.

The above described method is known and has previously been used, however, with a device different from the device 1 according to the invention. For a better understanding of the drilling and reaming procedure, reference is made, for example, to the above-mentioned publication.

The device 1 comprises a portion 2, which is intended to rotate, and a portion 3, which is intended not to rotate. When parallel, the portions 2 and 3 are essentially rotation symmetrical. The portion 2 is threaded at one end and is threaded to the drill string A by means of a threaded adapter 4. The portion 2 is provided with helical wings 5 of a major radial extension length exceeding that of the rest of the device. The portion 2 also has a central space 6, which is connected with the interior of the drill pipe and which is thus filled with pressurized fluid. The space 6 is connected with at least one, preferably several, jets 7 spaced apart over the circumference of the portion 2, making an angle with the longitudinal axis of the device. The portion 2 is formed with a sleeve 2a surrounding a body 8. A roller thrust bearing 9 is disposed between the portion 2a and the body 8 which is provided with a key handle. In the device 1, the pieces connected with the portion 2a are rotatably connected with the pieces hereinafter described connected with the body 8.

A shank 11 is threaded to the body 8 and to an end portion 12. The shaft 11 is provided with a spherical bearing 13, in which a ball joint 14 is journalled for pivotal move- ment in all directions relative to the shέihk 11 and therefore to the portion 2. The ball joint 14 is mounted on a shaft 15, which in turn is mounted in a body 16. A frustrum of a cone 17 is threaded to the body 16 at its narrowest end, and at its other end is provided with a screw head 17b used for threading the cone. A cylindrical helical spring 18 is disposed between the body 16 and a plurality, such as four, jaws 19, which spring urges the jaws towards the right-hand end position shown in the figure, in which position they bear on an annular step 17c on the cone 17. The jaws 19 are pressed against the mantle surface of the cone 17 by an o-ring 20 and are spaced apart in the direction of circumference so as to be axially displaceable towards the left and at the same time radially inwards without colliding.

The device 1 has a generally smooth outer surface and, with the exception of the wings 5, has no major recesses, projections or the like, into which or against which stone blocks could fall from the walls of the drilled hole, thus impeding the pulling of the device through the hole.

When the hose B is to be attached to the portion 3 of the device 1, a sleeve 21 is first passed onto one end of the hose, and the portion 3 is then applied to the hose with sleeve, so that the end of the hose will displace the jaws 19 towards the left against the spring force. At the same time, the jaws will be displaced radially inwards by means of the o- ring, so that the hose will be located radially outwardly of same. Displacement of hose B with sleeve 21 towards the left will occur until the upset end 21a of the sleeve bears on an inclined surface 12a formed on the end piece 12, the centre of curvature of said surface coinciding with the centre of curva¬ ture of the joint 14, and the end of the hose bearing on the inner surface of the upset end, as shown in the figure. The hose B is prevented from being pulled out of the portion 3 by the jaws 19 with their cogged or grooved, radially outer surfaces pressing the hose against the sleeve 21, the pressure increasing with increased pulling of the hose in the right-hand direction of the figure. After the device 1 has also been connected with the drill string A via the adapter 4, the drill string is rotated at the same time as it is pulled in the left-hand direction of the figure into and then inside the previously drilled hole, the rotating wings 5 and the pressure fluid emitted from the jets 7 reaming the hole and the hose B being passed through the reamed hole without rotating. During the reaming and the transport, the portions 2 and 3 will pivot relative to each other in order to follow the extension of the hole, whereby bending stress on the device 1 and the drill string A will b avoided. The pivotal movement into various positions takes place without particles or blocks coming down from the wall the hole being able to get to the joint 14, since said joint is fully encased in the device by the end piece 12, sleeve 2 and hose B. During pivoting of the portion 3 elative to the portion 2, the end 21a of the sleeve 21 will always be locat at a very short distance from the surface 12a of the end pie 12, thereby preventing major particles from entering. Sliould more complete sealing between the end 21a and the surface 12 be desired, an elastic sealing ring (not shown) may be mount to the end 21a, or the end piece 12 may be pressed against said end by spring force. When the device 1 with hose B has been pulled out of the reamed hole, the device 1 is detached from the drill string A and the hose B. Detachment of the hose from the device takes place by cutting the hose adjacent the end of t hose attached to the portion 3, and a tnin-walled sleeve, whose outer diameter is slightly smaller than the inner diameter of the hose, and whose inner diameter is slightly bigger than the major outer diameter of the cone 17, is inserted in the hose end and is pressed against the jaws 19 which will thereby be axially displaced towards the left and radially inwards in the figure. It will then be easy to pull the sleeve 21 and the hose end away from the device.

Although only one embodiment of the present invention has been described above and shown in the drawings, it will understood that the invention is not limited to said embodi- ent but only by what is stated in the claims.

Claims

1 A device for reaming an elongated hole formed in the ground and for transporting an elongated element through the reamed hole, comprising a reaming portion (2) provided with means (4) for connection with a rotating element (A), and a transport portion (3) which is pivotally connected with the reaming portion and provided with means (18 - 20) for connec¬ tion with the elongated element (B) , characterized in that th connection between the two portions (2, 3) comprises a joint (13, 14) making possible the relative pivoting of said portions in all directions.

2 A device according to claim 1, characterized in that the joint (13, 14) is a ball joint (13, 14). 3 A device according to claim 1 or 2, characterized in that the joint (13, 14) is disposed inside the device, so as to be protected by same independently of the relative pivotal positions of the two portions (2, 3).

4 A device according to any of the preceding claims, characterized in that it is preferably rotation symmetrical and formed in such a way that pieces coming loose from the ground around the hole will not get stuck between the walls o the hole and the device.

5 A device according to any of the preceding claims, characterized in that the transport portion (3) is provided with engagement means (18 - 20) which are withdrawable by the elongated element (B) formed as a hose or the like in connec¬ tion with the detachable attachment of same to the transport portion and which prevent removal of the elongated element from the transport portion.

6 A device according to claim 5, characterized in that the engagement means (18 - 20) include jaws (19) which are axially and radially displaceable along a preferably conical surface (17) inclining relative to the longitudinal axis of the device, the jaws being displaced towards the elongated element (B) by means of a spring force (18), said element being intended to be inserted between the outer surfaces of the jaws and a preferably detachable sleeve (21) surrounding said surfaces.

7 A device according to any of claims 1 - 5, charac¬ terized in that a sleeve (21) is mounted on the transport portion (3) at least partly surrounding same, the sleeve bein disposed at a small distance from the reaming portion (2) or sealingly sliding on a surface (12a) of said reaming portion during the relative pivoting of the two portions (2, 3).