CZ7993A3 - equipment for vibrating drilling with return circulation of fluid - Google Patents

Abstract

The drill bit (1) for a hammer drill has longitudinal grooves in its outer surface and a tube fits over the shank of the drill bit so that passageways (10) are formed for a cooling medium which also removes the fragments of material. The passageways run into an annular chamber (12) formed by circumferential groove (12) in the drill bit. This annular chamber is connected by a passageway (15) to a recess (13) in the end face of the drill bit. The recess is connected to a central axial hole through a short oblique hole (22) so that the cooling medium flows back through the axial hole. ADVANTAGE - The oblique hole improves the efficiency of the circulation of the cooling medium.

Description

Advox.ítní a patentová kancelářSR Čermák, HořejS, Vrba

NSrodnf 32 // '/ ý'

- PRAGUE 1 CS

Vibration drilling equipment with return fluid circulation

The invention relates to the field of research and use of a drill bed and relates to a new type of drill bit which is used in a drilling method known as vibratory drilling with a recirculating fluid circulation and a hammer outside the borehole.

It is known to use a sheath concentric with a drill pipe to drill with a recirculating fluid, whereby the drill fluid is injected into a circular space that separates the two members and the fluid then rises up along the crumb from the rock to the surface.

However, this drilling method has some drawbacks, especially when the fluid under pressure rises radially between the sheath and the drill bit head, with the result that cavities in the borehole wall are excavated in the case of soft rock parts, which adversely affect these cavities well rigidity and sometimes partial ingress of fluid between the sheath and the borehole wall, thus preventing good upward fluid flow.

In addition, the upward fluid flow and debris from the rock ascending through the central duct of the drill bit lead to wear on the cone of the duct, which gradually loses its corresponding calibration function and there is a risk that oversized debris from the rock may pass and obstruct flow through the drill pipe.

The invention can overcome these disadvantages by providing a drilling device characterized in particular by using a new type of drill bit, the head of which is provided at a groove circumference parallel to the bore axis and located in an extended portion of the circular chamber delimited by the drill bit neck and concentric sheath covering a drill bit head abutting a shoulder provided at the periphery of the drill bit head at a slight distance below said peripheral throat.

According to a further feature of the invention, the hole provided at the base of the drill bit for the upward flow of the grit is provided with protective elements, which are inserts of ultra hard material such as tungsten carbide, these inserts being angled to the upper periphery of the hole to reduce premature wear conduit.

Furthermore, the device according to the invention makes it possible to avoid hollowing out cavities in the borehole wall due to the fact that the drilling fluid can only be directed to the front opening of the drill pipe.

In addition, the drill bit opening may advantageously be provided with drilling rock elements constituted by ultra hard inserts arranged vertically and designed to crush the rock fragments before they reach the upward fluid flow in the vertical conduit as is conventional in the art. of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS The characteristics and advantages of the invention will be better understood by studying the following non-limiting description with reference to the accompanying drawings:

The drawings show:

- figure 1 shows a longitudinal sectional view of the lower end of the drilling device,

figure 2 shows a longitudinal view of a drill bit according to the invention,

figure 3 shows a front view of the drill bit arrangement according to the invention,

Figure 4 shows a front view of another drill bit arrangement according to the invention.

Figure 1 shows a drilling device made up of tubular interconnected elements forming a circumferential sheath 2 within which a drill pipe, also formed by tubular elements with contact ends, extends concentrically and thus the drill bit 1 forms an integral part of the drill bit.

** ** split pipe using sleeve 30.

... J

The annular space 31 between the drill pipe 3 and the inner wall of the sheath 2 allows the fluid flow indicated by the arrows towards the bottom of the well, whereby the fluid enters the surface along with debris fragments inside the drill pipe 3.

The lower end of the sheath 2 has longitudinal grooves 20 disposed within a certain length, into which longitudinal grooves 10 arranged on the periphery of the drill bit 1 are inserted so as to be integral with the sheath 2, the number of said longitudinal grooves 10 being less than the number of said longitudinal grooves. of the grooves 20 of the housing 2, so that the fluid can pass through the not shown grooves 20 and pass from the annular space 31 to the front end of the drill bit 1.

The longitudinal grooves 10 of the drill bit 1 are extended at their lower end to a peripheral neck 11 partially or completely covered by the sheath 2 to allow longitudinal shifting of the sheath relative to the drill pipe 3. When the sheath 2 is in extreme position known in FIG. , its base releases a large circumferential space 9 through which the radial fluid flows under pressure, resulting in a recess of the cavities in the borehole wall in the soft layers of soil.

In contrast to the unoccupied longitudinal grooves 20 of the sheath 2, the longitudinal orifices 10 'are arranged on the periphery of the drill bit 1 to allow fluid flow thereafter which extends below the drill bit 1 before it starts to rise again through the central bore 13 arranged in the base and then flows through the inclined conduit 22 extended into the axial tube 8 located in the extension of the drill pipe 3.

The hole 13 of the drill bit 1 is provided on its periphery with six carbide pins 27 inclined outwards and three pins 28 also made of tungsten carbide inclined inwards. The lower part of the opening 13 is provided at the entrance to the inclined pipe 22 with two vertically arranged rock crushing elements 29.

Figure 2 shows a drilling device according to the invention with a drill bit 1, the head of which is covered by an extension 21 of the shell 2, thereby forming a circular chamber 12 which remains further closed, whatever the position of the drill pipe 3 is; the end of the extension 21 completely covers the peripheral neck 11 of the drill bit 1 and abuts the arm 14 arranged on the drill bit 1.

The fluid from the annular space 31 flows to the bottom of the borehole 15 arranged on the periphery of the drill bit 1 parallel to the bore axis 3, the lower ends of the channels being expanded and open on the inside so that the fluid is oriented towards the central bore 13 the circumference of which are embossing plates 19, which thus form an embossing ring.

As shown in Figures 3 and 4, in order to reduce excessively rapid wear of the drill bit 1 with fluid and debris from the mine that carries the fluid, at the inlet of the conduit 22 through which the fluid filled with debris rises upwardly accommodates carbide pins 17. tunnel at the points of highest wear, ie approximately against the openings 16 of the channels 15 in order to protect the inlet into the conduit 22 so that its diameter is maintained and no excess soil debris can penetrate into the conduit 22 and thereby risk of blockage of the drill pipe.

Other rock crushing elements 18 located in the opening 13 allow fractionation of the fragments and additionally protect the opening 13.

The number and position of the wear pins 17 and rock crushing elements 18 may vary depending on the number and position of the channels 15 and the embossing plates 19. Thus, in the embodiment of Figure 3, the drill bit has five embossing plates 19 disposed between the holes 16 of the five channels 15, three wear pins 17 are arranged obliquely and one freshman for crushing rock 18 is positioned vertically. In the embodiment of Figure 4, the drill bit is provided with four embossing plates 19 disposed between the holes 16 of the six channels 15, the three wear pins 17 are inclined and one rock crushing element 18 is positioned vertically.

It goes without saying that the present invention is not limited to the description,

which is presented before some embodiments, but which may still have a certain number of modifications without departing from the scope of the invention. In particular, the drill bit shown in Figures 2,3 and 4 may be formed from elements other than inserts and may consist of elements commonly known as pins or pins.

Claims (3)

? // / y - ΰ S PATENT COVERS 1. Apparatus for vibratory drilling with a borehole and recirculating fluid, provided with a jacket concentric to the drill pipe, at the end of which a drill bit is provided by means of a sleeve with an axial pipe connected by an inclined pipe to the front hole characterized in that the drill bit (1) is provided at its lower end with a circular chamber (12) defined by an extension (26) of the sheath (2) and a circular neck (11) of the drill bit (1), on the arm (14) of the drill bit (1) located below said annular neck (11) and on its periphery are arranged channels (15) parallel to the axis of the drill pipe (3) having the lower ends (16) widened and open inwards for directing fluid into the opening (13) and into the inclined pipe (22) of said crown (1). Device according to claim 1, characterized in that the inlet circumference of the inclined pipe (27) is provided with protective obliquely arranged elements of ultra-hard material. Device according to claim 1 or 2, characterized in that the at least one rock crushing element (18) of the ultra-hard material is positioned vertically in the opening (13) below the inlet of the duct (22).