Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02208893 2004-11-09
Drilling apparatus
The invention relates to a drilling apparatus to drill a hole into the ground.
Drilling arrangements in which the hammering means operated by compressed
air, are placed advantageously at the drilling head of a down-the-hole drill,
have
already been known for a long time and they have also been widely used in
mining industry. An advantage of the hammering means being placed in the hole
is, that its strokes are applied directly to the drill bit, whereby it is
possible to
decrease energy loss and unnecessary wearing of components belonging to the
arrangement to lower level than in arrangements where the hammering means
are placed in the rear end of the drill rod. In pneumatic drilling machines
compressed air is usually used to flush drilling waste, also. However, it is
not
beneficial to use the drilling machine with compressed air, because a very
high
power compressor unit is thus needed. In addition, the efficiency of a
pneumatic
system is clearly lower than that of a hydraulic system.
The use of a hydraulic drilling machine is known for example from Patent
Publication PCT/4089/00256. The drilling device according to the above
publication is moved in an oscillating motion as distinct from the usual
rotational
motion, that takes place continuously in the same direction. The reason for
this is,
that for feeding of pressure medium into the hammering unit placed in the
drilling
head, separate feeding hoses are used, whereby, when adding or removing drill
rods to/from the drilling device, the feeding hoses are fed into the hole or
wound
up from the hole. To achieve an optimum drilling effect and to prevent damage
to
the feeding hoses, the twisting angle is preferably limited between
180° - 360°. To
minimize wear of the feeding hoses, an application is described in the
publication,
in which each drill rod has two longitudinal ducts that are open outwards, in
which
the feeding hoses are placed for feeding and leading off of the pressure oil
for the
hammering unit of the drilling device placed in the hole. The hydraulic hoses
are
thus advantageously inside the circle of the drill rod. Feeding of the
compressed
air is carried out advantageously by applying conventional techniques and
leading
it through the hollow drill rod.
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The solution according to the publication above is not very good in practice,
because the handling of feeding hoses requires massive equipment. It is
necessary to arrange winding drums and driving mechanisms for both feeding
hoses, the space utilization of which is determined by the depth of the hole
to be
drilled. The handling of the feeding hoses during a drilling situation is
naturally
difficult, wherein careless installation and use may cause environmental
damage
when the feeding hoses are injured. When drilling holes are different depths,
corresponding hoses of different lengths must be used or they must be
lengthened with joints, which again causes environmental risks. The hydraulic
hammer placed in the front end of the drill rods is not described in greater
detail in
the publication.
Thus it is known from both pneumatic and hydraulic drilling apparatus to
place the hammering unit inside the protecting tube at the drilling head. In
this
case there has been placed inside the frame of the hammering unit a valve and
flow directing arrangement controlling the flow of pressure medium and a
piston
arrangement carrying out the said hammering motion by influence of the above.
In
conventional constructions the flow ways of the second flow arrangement, that
are
in connection with the hammering unit, are formed of one input flow way and of
one output flow way. In addition to that, when placing the hammering unit at
the
drilling head of the drilling device, there must be placed a flushing duct,
acting as
the first flow arrangement, in the hammering unit, also. This is why, when
applying
traditional solutions, the cross section of the hammering unit always gets
relatively
big, which fact naturally has a remarkable influence on the overall
construction
and the manufacturing costs of the drilling device. On the other hand
solutions are
known from certain types of drilling devices, also, in which particularly for
minimizing the cross section of the hammering means, a flow way of the second
flow arrangement, essentially in connection with the same, such as an input
flow
way and/or an output flow way, is divided into two or more flow parts.
One practical problem concerning present down-the-hole drills is
particularly the controlling of the pressure medium of the hammering means,
whereby it is known for example from EP-application 22865 to apply an
accumulator arrangement, placed essentially apart from the hammering means, to
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stabilize pressure levels. In this case it is necessary to use a separate
compensation device, which has dividing places for the flow ways, between the
drilling device and the drill rod being attached to the same. The solution in
question is inconvenient particularly in the sense of manufacturing and
maintenance because of its complicated construction.
It is an aim of the drilling apparatus embodying this invention to achieve a
decisive improvement in the problems presented above and thus to raise
substantially the level of knowledge in the field. To achieve this aim, the
new
drilling apparatus is primarily characterized in that the drilling device
includes an
accumulator arrangement or a like, for storing pressure medium, in connection
with the second flow arrangement, that is arranged in the longitudinal
direction
immediately after the hammering means and which is placed preferably centrally
on the same longitudinal axis between the piston arrangement of the hammering
means and the dividing arrangement of the flow ways.
The most important advantages of the new drilling apparatus are the
simplicity of its construction and profitableness particularly in the sense of
manufacturing costs. It is possible to optimize the cross section of the
hammering
means in a way, that placing of the hammering means immediately after the
drill
bit at the drilling head does not make any extra demands for example on the
dimensioning of the protecting tube covering the hammering means and the drill
rods. In addition to that, the hammering means and the accumulator
arrangement,
when being arranged as an integrated entirety and placed directly after one
another, may be changed by cartridge principle as a whole, when required. This
makes the maintenance particularly of the components in question much easier,
because in this case either one of them may be taken in for service as a
whole,
when required, whereby a new corresponding component may be installed in the
drilling device immediately in the place of the same. In addition to that,
when
placing the accumulator arrangements as near as possible to the hammering
means, problems concerning loss of pressure or the like may be avoided.
More particularly in accordance with the invention there is provided, drilling
apparatus drilling apparatus which comprises a drilling device having a
drilling end
which includes a drilling means for drilling a hole and an other end which
includes
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jointing means for fastening a drill rod to increase drilling depth of the
apparatus,
the drilling device operating as a down-hole drill by a feeding motion in a
longitudinal axis direction of said drilling device and by a reciprocating
hammering
motion along and by rotational motion around the longitudinal axis, flushing
means
for removing drilling waste generated by the drilling means including a first
flow
arrangement for leading a flushing medium therefor, hammering means
cooperating with said drilling means comprising: a hollow frame part, a piston
arrangement in said hollow frame part, a second flow arrangement connected to
a
pressure medium system of the drilling apparatus for actuating said piston
arrangement with a valve and flow directing arrangement to provide said
hammering motion, the second flow arrangement comprising a pair of flow ways
having at least one flow way divided by a dividing arrangement into at least
two
flow parts, and an accumulator arrangement for storing said pressure medium
located in said longitudinal axis direction away from said drilling means,
beyond
the said piston arrangement and between said piston arrangement and the
dividing arrangement of said flow way.
Embodiments of the drilling apparatus according to the invention are
described with reference to the accompanying drawings, wherein:
Fig. 1 shows a view, that is half-cut longitudinally from separate places, of
a drilling apparatus according to the invention, wherein the
hammering means are placed in connection with the drill bit,
Figs. 2a and 2b
show cross sectional views along lines Y-Y and X-X in Fig. 3,
Fig. 3 shows a partial longitudinal section of a dividing arrangement placed
in connection with the hammer means,
Fig. 4 shows a longitudinal section of the hammering means, that are
arranged, as an advantageous embodiment of the invention, as an
integrated entirety, and
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Fig. 5 shows an advantageous piston arrangement of the drilling apparatus
according to the invention.
Drilling apparatus to drill a hole into the ground, whereby the drilling
apparatus has at least:
- a drilling device 1, the drilling end I of which includes at least drilling
means 2 for
drilling a hole and the other end II of which includes jointing means 3 for
fastening
of a drill rod 4 to increase the drilling depth of the drilling apparatus. The
drilling
device 1 is arranged to operate as a down-the-hole drill by a feeding motion
along
its longitudinal direction s and by a to-and-fro or a like hammering motion t
as well
as by a rotational motion w around its longitudinal axis s. In connection of
the
drilling device 1 there exists preferably flushing means 5 to remove drilling
waste
generated by the drilling means 2, that are arranged functional by flushing
medium led by a first flow arrangement 6, and
- hammering means 8, placed in connection with the drilling means 2 in the
drilling device 1, to achieve a hammering motion, that are arranged functional
by
pressure medium in liquid form led by a second flow arrangement 9 from the
pressure medium system of the drilling apparatus. The hammering means 8
include a hollow frame part 7, which has, at least to achieve a hammering
motion,
a valve and flow directing arrangement o controlling the flow of pressure
medium
taking place at the hammering means 8 and a piston arrangement 10 carrying out
the said hammering motion by influence of the above, wherein particularly at
least
to minimize the cross section of the hammering means 8, at least one flow way
of
the second flow arrangement 9, essentially in connection with the same, such
as
an input flow 9a and/or an output flow way 9b, is divided in two or more flow
parts.
The drilling device 1 includes as well as an accumulator arrangement 11 or
a like, for storing pressure medium, in connection with the second flow
arrangement 9, that is arranged in the longitudinal direction s immediately
after
the hammering means 8 and which is placed preferably centrally on the same
longitudinal axis s between the piston arrangement 10 of the hammering means 8
and the dividing arrangement 13 of the flow ways.
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In the embodiment presented in fig. 1 the hammering means 8 are
arranged inside a protective tube SP, shown by a line of dots and dashes, in
connection with the drill bit 2, shown correspondingly by a line of dots and
dashes.
In this case for leading of flushing medium, the first flow arrangement 6 is
arranged to be led centrically through the piston arrangement 10, in which
case in
the other end II of the drilling device 1 there exists coupling means 12 in
addition
to the jointing means 3, to couple the first flow arrangement 6 and the second
flow
arrangement 9 with an input flow duct 9a', an output flow duct 9b' and a
flushing
medium duct 6', that exist in a drill rod 4 being connected to the drilling
device 1.
In this case, the first flow arrangement 6 for leading of flushing medium is
arranged, as an advantageous embodiment of the invention, to be directed
centrally through the accumulator arrangement 11 placed after the piston
arrangement 10, that is situated at the drilling end I of the drilling device
1. As an
advantageous embodiment, the accumulator arrangement 11 is connected to the
flow parts 9a1, 9a2, 9a3, 9a4 and 9b1, 9b2, 9b3, 9b4 of the input flow way 9a
and
the output flow way 9b of the second flow arrangement 9. (See also Fig. 2a, 2b
and 3.)
With reference to figs. 1, 4 and 5 the piston arrangement 10 of the
hammering means 8 includes at least one slide piston 10a moving in the
longitudinal direction s of the frame part 7, the first end I' of which acts
as a
hammering head, whereby the hammering means 8 include as well coupling
means 12 to couple the flow ways 9a, 9b of the second flow arrangement 9, that
are in connection with the hammering means 8, with the pressure medium system
of the drilling apparatus. In this case in connection with the hammering means
8
there has been arranged a dividing arrangement 13, as shown in figs. 1 and 3,
to
divide the input flow way 9a and the output flow way 9b of the second flow
arrangement 9, that are connected to the piston arrangement 10 belonging to
the
hammering means 8, into several flow parts by dividing points J1, J2 placed
advantageously at a distance a from each other in the longitudinal direction
s.
The flow ways 9a, 9b of the second flow arrangement 9 in connection with
the hammering means 8, are advantageously each formed of a recess, such as a
groove or a like, placed on the outer surface of piston arrangement 10
essentially
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in the longitudinal direction s, whereby flow of the pressure medium in
connection
with the hammering means 8 at least partly takes place between the piston
arrangement 10 and the frame part 7. In this case as an advantageous
embodiment, the flow parts of the flow ways 9a, 9b of the second flow
arrangement 9 in at least part of the piston arrangement 10 are arranged, when
viewed cross sectionally, symmetrically, preferably as recesses placed on the
outer surface of the piston arrangement 10 in the longitudinal direction s.
Further,
as an advantageous embodiment, the input flow way 9a and the output flow
way 9b of the second flow arrangement 9, that are in the piston arrangement
10,
are divided into tour parts 9a1, 9a2, 9a3, 9a4, 9b1, 9b2, 9b3, 9b4, each,
whereby
they are arranged, when viewing also the piston arrangement 10 cross
sectionally,
preferably in turn at an angle of 45° in relation to each other, as in
figs. 2a and 2b,
and on the outer surface of the piston arrangement 10, as shown in fig. 5. The
reference letter o in fig. 5 represents a control flow duct of the valve
arrangement
and the reference code tv represents a leak flow duct of the gaskets.
As a particularly advantageous embodiment with reference to fig. 4, the
hammering means 8 are arranged as an integrated entirety, such as a cartridge
or
a like, that may be installed/removed essentially as a whole from the drilling
apparatus. This matter has a very remarkable meaning concerning maintenance
carried out at the working site, because when applying traditional solutions,
the
operations concerning particularly the hammering means must be carried out by
removing the parts belonging to the hammering means nearly one at a time from
the drilling apparatus.
Further, with reference to fig. 4, to form an integrated entirety, the first
end
I' of the frame part 7 is closed by means of a closing part 15, that is
connected to
the frame part 7 by fixing means 14, such as by welding, screw coupling or
correspondingly, whereby at the other end II' of the frame part 7 there is a
shoulder 16, that restricts the movement of the piston arrangement 10 in the
longitudinal direction s. Further, as an advantageous embodiment, the frame
part
7 surrounding the hammering means 8 includes at the other end II' of the same
an
extension part 7', that starts from the bottom part 16 and is directed in the
longitudinal direction s away from the piston arrangement 10, for the
installing of
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the accumulator arrangement 11 and the dividing arrangement 13 inside the
extension part 7'.
It is obvious, that the invention is not limited to the embodiments presented
or described above instead it can be modified to a great extent within the
basic
idea. For one thing the hydraulic fluid of the hammering means may be
transmitted in connection with the drill rods by feeding hoses or
correspondingly.
Correspondingly the first flow arrangement of the flushing means may be formed
of two ducts, whereby feeding of the flushing medium takes place through the
first
duct and suction of the flushing medium takes place through the second duct
through interiors of the drilling device and the drill rods. Correspondingly,
the
turning motion of the drilling apparatus may be arranged reciprocating,
whereby,
however, a more complicated and uncertain controlling and regulating technics
is
required than that for the above described application.
