NZ606411B - Method and apparatus for controlling the operation of cluster drill of down-the-hole hammers - Google Patents
Method and apparatus for controlling the operation of cluster drill of down-the-hole hammersInfo
- Publication number
- NZ606411B NZ606411B NZ606411A NZ60641113A NZ606411B NZ 606411 B NZ606411 B NZ 606411B NZ 606411 A NZ606411 A NZ 606411A NZ 60641113 A NZ60641113 A NZ 60641113A NZ 606411 B NZ606411 B NZ 606411B
- Authority
- NZ
- New Zealand
- Prior art keywords
- drill
- hammers
- dth
- cluster
- compressed air
- Prior art date
Links
- 238000000034 method Methods 0.000 title description 8
- 238000009527 percussion Methods 0.000 abstract description 43
- 239000012530 fluid Substances 0.000 abstract description 31
- 238000005553 drilling Methods 0.000 abstract description 23
- 230000015572 biosynthetic process Effects 0.000 abstract description 13
- 230000000295 complement effect Effects 0.000 abstract 2
- 238000005755 formation reaction Methods 0.000 abstract 1
- 230000003116 impacting effect Effects 0.000 description 6
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000011435 rock Substances 0.000 description 2
- 238000012358 sourcing Methods 0.000 description 2
- 235000012571 Ficus glomerata Nutrition 0.000 description 1
- 240000000365 Ficus racemosa Species 0.000 description 1
- 235000015125 Sterculia urens Nutrition 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 238000009435 building construction Methods 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- KISFEBPWFCGRGN-UHFFFAOYSA-M sodium;2-(2,4-dichlorophenoxy)ethyl sulfate Chemical compound [Na+].[O-]S(=O)(=O)OCCOC1=CC=C(Cl)C=C1Cl KISFEBPWFCGRGN-UHFFFAOYSA-M 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B4/00—Drives for drilling, used in the borehole
- E21B4/06—Down-hole impacting means, e.g. hammers
- E21B4/14—Fluid operated hammers
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B4/00—Drives for drilling, used in the borehole
- E21B4/16—Plural down-hole drives, e.g. for combined percussion and rotary drilling; Drives for multi-bit drilling units
Abstract
606411 An apparatus (100) for drilling hole in mixed ground formations is disclosed. The apparatus has a cluster (101) of two or more down-the-hole (DTH) percussion hammers (102). Each is driven from an independent supply source of compressed air or pressurized fluid. At least one hammer is driven from a supply source which is different from the supply source of the other hammers. A special distributor (104) with rotatable swivels (110, 111) is used to connect and distribute the supply sources to the DTH percussion hammers. The drill string length can be extended using drill pipes (103) formed with complementary conduits (112) for the supply sources. The hammers are arranged such that one or more circumferential layers of drill bits are formed covering the drilling area. Drills able to create circular and annular hole are disclosed. from a supply source which is different from the supply source of the other hammers. A special distributor (104) with rotatable swivels (110, 111) is used to connect and distribute the supply sources to the DTH percussion hammers. The drill string length can be extended using drill pipes (103) formed with complementary conduits (112) for the supply sources. The hammers are arranged such that one or more circumferential layers of drill bits are formed covering the drilling area. Drills able to create circular and annular hole are disclosed.
Description
METHOD AND APPARATUS FOR CONTROLLING THE ION OF
CLUSTER DRILL OF DOWN-THE-HOLE HAMMERS
Field of the Invention:
The present invention relates lly to civil building construction.
More specifically, the present invention relates to ques and equipments used in
building structural tion piling. Still more specifically, the present invention
relates to methodology and equipment for controlling the operation of cluster drill of
down—the—hole (DTH) percussion hammers for drilling in ground.
Background:
Conventional ground drilling ents or techniques normally drill
holes with a single or outer diameter (OD) target. Depending on the ground condition,
a casing sometimes is inserted in the ground to prevent collapse of soil when the
ground condition is loose. In the case where the ground strata are stable, no casing is
necessary to be inserted to the ground. In either case, all the als inside the hole
will needed to be excavated away in the process of drilling.
The single DTH percussion hammer is well known in its use for
general ground drilling. The DTH percussion hammer can be driven by either
compressed air or pressurized fluid such as water.
A cluster drill of DTH sion hammers is an implementation of a
plurality of DTH hammers arranged and allocated in a cylindrical housing of which
the OD defines the diameter of the hole drilled. One such implementation is shown in
Figure 1. The ity of DTH hammers can also be arranged and allocated in an
annulus housing having an OD and an inner diameter (ID) ed to drill ring holes
with a particular size. One such implementation is shown in Figure 2. In both cases,
the OD of the hole to be drilled can range from a minimum of 300mm to any diameter
length. There is no theoretical maximum limit to the size of the hole as there can be
many different possible arrangements of the ity of DTH hammers. In the case of
drilling s ring holes, the ID of s ring hole can range from a minimum of
200mm to any larger diameter length.
Contemporary designs and arrangements for the cluster drill of DTH
sion hammers often have centralized supply sources of compressed air or
pressurized fluid for their hammer g mechanisms. The compressed air or
pressurized fluid delivery paths branch out to all the DTH percussion hammers so that
each of them can actuate its corresponding piston to strike on its front drill bit. With
this configuration, the cluster drill of DTH percussion hammers assembly can hammer
and penetrate homogenous hard als or ground formation over its drilling area.
In other words, when all the DTH sion s are simultaneously impacting
the homogenous hard materials or ground formation, there will be enough evenly
distributed on force feedback on to the drill bits and in turn pushing back on to
the pistons to facilitate the hammering cycle.
However, a problem arises in practice when the cluster drill of DTH
percussion hammers is needed to drill mixed ground formation comprising materials
of different rigidities. While the hard ground formation can provide enough reaction
force feedback on to a drill bit to facilitate the continuation of hammering cycle of its
corresponding piston, soft ground formation does not provide sufficient reaction force,
causing the drill bit to drop and rest on the drill bit retaining ring. Following the drill
bit, the piston also rests on top of it. The compressed air or pressurized fluid then
escapes directly from the drill bit through the main exhaust holes in piston instead of
going through the bottom chamber, which normally feeds the piston for the return
stroke in a normal hammering cycle if the ground is hard enough to provide sufficient
reaction force. At this point, the DTH hammer is at the maximum flushing position
with the ssed air or pressurized fluid supplied to it being directly released out
through its bottom of the drill bit. This condition is called the “direct exhaust
phenomenon.”
The condition described above is the result of that compressed air or
pressurized fluid being delivered from a single centralized supply source for the
operation of all the DTH sion hammers in the cluster of DTH percussion
s assembly. The direct exhaust enon occurred in the DTH percussion
hammers (or even in a single DTH percussion hammer) that are impacting soft
ground. It led to the bypassing of all compressed air or pressurized fluid from the
lized supply source through these direct exhaust path(s) because of the much
less flow ance through the bottom of the drill bit(s); as opposed to the much
higher flow resistance experienced when the compressed air or pressurized fluid is
driven on the (s) of those DTH percussion hammer(s) that are impacting on hard
ground.
Furthermore, due to the release of the compressed air or pressurized
fluid through the lesser flow-resistive path(s) associated with the DTH percussion
hammer(s) that are impacting soft ground; there is insufficient compressed air or
pressurized fluid left to drive the other piston(s) of those DTH percussive (s)
that are impacting hard ground. uently, the piston(s) of the DTH percussive
(s) that are impacting hard ground cease. Therefore, when the cluster drill of
DTH percussion hammers encounter mixed ground formation during drilling, it cannot
penetrate any more at that ground depth and the drilling cannot proceed further.
In fact, the aforementioned condition is the limitation of application of
contemporary designs of cluster drills of DTH percussion hammers in drilling works,
that is they can only be used in drilling homogeneous or competent rock strata, but not
mixed ground formation. Therefore, there is a need for equipments and/or
methodologies for controlling the operation of cluster drill of DTH percussion
hammers for drilling mixed ground formation.
Summary:
It is an objective of the presently claimed invention to provide a
method and an apparatus for lling the ion of cluster drill of down—the-hole
(DTH) percussion hammers. It is a further objective of the presently claimed
invention to enable the cluster drill of DTH sion hammers to drill not only in
homogeneous ground formation, but also mixed ground formation sing both
hard and soft ground formation.
Brief Description of the Drawings:
Embodiments of the invention are described in more detail hereinafter
with reference to the drawings, in which
Figure 1 shows the cross sectional view and the bottom views of an
exemplary embodiment of a drill string that includes a cluster drill of DTH percussion
hammers;
Figure 2 shows the cross sectional View and the bottom View of one
embodiment of a drill string for annulus ring hole drilling;
Figure 3 shows the cross sectional View of one embodiment of the
cluster drill ofDTH percussion hammers for annulus ring hole drilling; and
Figure 4 shows the magnified cross sectional view of the rotary head
and the special distributor of one embodiment and illustrates the flow of compressed
air or pressurized fluid from multiple sources.
Detailed Description:
In the following description, methods and apparatus for controlling the
operation of r drill of down—the-hole (DTH) percussion hammers and the like are
set forth as preferred examples. It will be apparent to those skilled in the art that
ations, including additions and/or tutions may be made Without departing
from the scope and spirit of the invention. Specific details may be omitted so as not to
obscure the invention; however, the disclosure is written to enable one skilled in the
art to practice the teachings herein without undue experimentation.
ing to the cross sectional view of an exemplary embodiment of a
drill string 100 as shown in Figure 1. The drill string 100 includes a cluster drill of
DTH percussion hammers 101, which includes one or more DTH hammers 102
ed and allocated in either a cylindrical housing or an annulus housing; one or
more drill pipes 103; a special distributor 104 of compressed air or pressurized fluid
having one or more rotatable intake swivels, such as 110 and 111 as shown, for
sourcing the compressed air or rized fluid; and a rotary head connection
interface 105 for connecting a rotary head 106. In some cases of shallow drilling, no
drill pipe is necessary.
The cluster drill of DTH sion hammers 101 includes one or more
DTH hammers 102 arranged and allocated in either a cylindrical housing or an
s housing. With cylindrical housing, the housing OD defines the er of
the circular hole drilled. With annulus g, the size of the annulus ring hole
drilled is determined by the OD and ID of the annulus housing. The cluster drills of
DTH percussion hammers in cylindrical housing and s housing are two typical
embodiments. The presently claimed invention is applicable to many modifications
and variations of cluster drill of DTH percussion hammer designs that are apparent to
the practitioner skilled in the art.
In accordance to an embodiment of the presently claimed invention, the
special distributor 104 of ssed air or pressurized fluid ses one or more
rotatable intake swivels, such as 110 and 111 as shown, for sourcing the compressed
air or pressurized fluid. The one or more rotatable intake swivels are constructed
purposely to allow independent supply of compressed air or pressurized fluid from
each rotatable swivel to drive the DTH sion hammers of the cluster drill. This
is in contrast to the conventional design of using a single centralized supply source of
compressed air or pressurized fluid to drive all the DTH percussion hammers. The
number of rotatable swivels needed depends on the configuration and size of the
cluster drill of DTH percussion hammers.
The rotary head 106 provides rotational turning speed and output
torque for the drill string 100. The rotary head 106 is also equipped with an intake
swivel 107 where ssed air or pressurized fluid is supplied from a source, which
can be independent of those supplying the special distributor 104 through its one or
more rotatable intake swivels. The compressed air or pressurized fluid is then
delivered through the internal channel in the rotary head 106 to the internal channel in
the rotary head connection interface 105. Figure 4 shows the magnified cross
sectional View of the rotary head and the special distributor. Different sources of
compressed air or pressurized fluid are ing through the intake swivel 401 of the
rotary head and the rotatable intake swivels 402 and 403 of the special butor; and
the compressed air or pressurized fluid travel through te paths 411, 412, and 413
respectively to the corresponding DTH percussion hammers.
One or more drill pipes 103 are attached vertically, providing the
extension lengths for the drill string 100 to meet the drill depth requirement. Internal
delivery pipes 112 are ed from top to bottom inside each of the drill pipes 103.
Compressed air or pressurized fluid is delivered through the internal delivery pipes
112 and reaches the r drill of DTH percussion hammers 101. When two drill
pipes are vertically attached, their respective delivery pipes are internally aligned and
connected, forming the continuous delivery channels for the compressed air or
pressurized fluid supplied h the rotatable swivels of the special distributor 104
and the intake swivel of the rotary head 106. Each DTH percussion hammer is
connected to one delivery pipe. The drill pipes 103 also er the rotational torque
from the rotary head 106 to the cluster drill ofDTH percussion s 101. In some
cases of shallow drilling, no drill pipe is necessary. In those cases, the cluster drill of
DTH sion hammers 101 is directly connected to the special distributor 104.
Depending on the requirement of the hole to be drilled, various
tion arrangements of the drill bits are possible. In the case of annulus ring hole,
if the difference between the annulus ring hole OD and ID is small, one
circumferential layer of drill bits is used. For an annulus ring hole with a large OD—ID
difference, two or more circumferential layers of drill bits can be o cover the
large annulus ring drilling area. Similarly for ng large circular holes, two or more
circumferential layers of drill bits can be used to cover the drilling area.
ing to the bottom Views 120 and 121 of an exemplary
configuration of a cluster drill of DTH percussion hammers shown in Figure 1, in
which two circumferential layers of drill bits are arranged from the center of the
cluster drill of DTH percussion hammers 101 to its outermost diameter as viewed from
the bottom. The ng area that can be formed by each drill bit is governed by the
swept area produced by its revolving motion about the rotational axis of the cluster
drill of DTH percussion hammers 101. It is common to te the drill bits in cluster
drill in such a way that summation of the drilling area formed by all drill bits located
at different radial distance from the center of the cluster drill will fully cover the entire
cluster drill bottom face area.
Referring to Figure 2. Another ary configuration of a cluster
drill of DTH percussion hammers is shown. As shown by the bottom view 210, one
circumferential layer of drill bits is used in an annulus ring housing for ng
annulus ring holes.
In accordance to an embodiment of presently disclosed invention,
within each circumferential layer of drill bits there is at least one drill bit’s
corresponding DTH percussion hammer is supplied with an independent source of
compressed air or pressurized fluid through one of the rotatable swivels, such as 110
and 111, of the special butor 104, or the intake swivel 107 of the rotary head 106.
For the exemplary configuration of a cluster drill of DTH percussion
hammers as shown in Figure 1, since there are two circumferential layers, there are at
least two independent supply sources of compressed air or pressurized fluid and three
rotatable swivels in the special distributor 104. In this exemplary embodiment, the
inner circumferential layer of drill bits comprises only one drill bit 122. Its DTH
percussion hammer is supplied with compressed air or rized fluid from an
independent supply source through the rotatable swivel 110 of the special distributor
104. The outer circumferential layer comprises four drill bits 123, 124, 125, and 126.
The DTH percussion hammer of drill bit 123 is selected to be independently supplied
with compressed air or rized fluid from an independent supply source through
the ble swivel 111 of the special distributor 104. The DTH percussion hammers
of drill bit 124, 125, and 126 are ed with compressed air or pressurized fluid
from a l supply source through the intake swivel of the rotary head.
In the situation where the drill bit 124, 125, or 126 hit on mixed ground
formation during drilling and causes direct exhaustion of the compressed air or
pressurized fluid from the central supply source - direct exhaust enon.
However, since the DTH percussion hammer of drill bit 123 is supplied by an
independent compressed air or pressurized fluid source, it can continue to hammer and
penetrate the mixed ground. Once more solid rock strata are reached, the halted DTH
percussion hammers of drill bit 124, 125, or 126 can restart hammering.
In accordance with s embodiments, specially designed
percussion drill bits with en carbide tips are mounted at the bottom of each drill
bit. The drill bit has a special peripheral profile to achieve a larger percussion area on
both the annulus OD and ID drilling areas. The drill bit cutting face profile is not
necessary circular in shape, and can be triangular, gular, or any special profiled
shape.
The foregoing description of the present invention has been provided
for the purposes of illustration and description. It is not intended to be tive or
to limit the invention to the precise forms disclosed, Many modifications and
variations will be apparent to the practitioner skilled in the art.
The embodiments were chosen and described in order to best explain
the principles of the invention and its practical application, thereby enabling others
skilled in the art to understand the invention for various ments and with various
modifications that are suited to the particular use contemplated. It is intended that the
scope of the invention be defined by the following claims and their equivalence
WHAT I/WE
Claims (1)
1. CLAIM 2001 ..v1.1vavvv....nwuv.+i,w_._fl Llfifi . -_nIEmPE.l. : .33? auE,...m3My. Figllrs 4
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
HK12101330.3 | 2012-02-10 | ||
HK12101330.3A HK1155608A2 (en) | 2012-02-10 | 2012-02-10 | Method and apparatus for controlling the operation of cluster drill of down-the-hole hammers |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ606411A NZ606411A (en) | 2014-05-30 |
NZ606411B true NZ606411B (en) | 2014-09-02 |
Family
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