Note: Descriptions are shown in the official language in which they were submitted.
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a.
SELF-CARRYING ABRASIVE TYPE HYDRAULIC SLOTTING DRILL
BIT
FIELD OF THE INVENTION
[0001] The present invention relates to a hydraulic slotting drill bit, and in
particular to a self-
carrying abrasive type hydraulic slotting drill bit, belonging to the
technical field of mining
engineering.
DESCRIPTION OF RELATED ART
100021 Hydraulic fracturing technology was first applied to petroleum
engineering to increase
the production of lean oil wells. At present, the hydraulic fracturing
technology has been
promoted and applied in the aspects of hard roof control of coal mines,
submarine tunnel
engineering, hard top coal weakening, rock fracturing, coal bed methane
mining, and the like.
Generally, the initiation and propagation of a hydraulic fracture are
controlled by the ground
stress field of drilled surrounding rock, and the fracture initiation and
propagation plane is
parallel to the direction of maximum principal stress. However, the fracture
propagation
direction required in many projects does not coincide with the fracture
direction controlled by
the ground stress field, and artificial measures are required to control the
directional initiation
of the fracture and guide the propagation direction of the fracture, that is,
directional hydraulic
fracturing.
100031 The most common method of the directional hydraulic fracturing is to
cut a fracture in
a specific direction with high pressure water jet on a drilled wall to guide
the hydraulic fracture
to propagate in the cutting direction so as to achieve the effect of
directional fracturing. On the
ground, the high pressure water jet is widely used, wherein a water jet
scalpel is a common
cutting technology using the high pressure water jet. The water jet scalpel is
a cutting tool using
water as a scalpel. This technology originated in the United States and was
used in the
aerospace military industry. It is favored for its cold cutting without
changing the physical and
chemical properties of a material. After continuous improvement of the
technology, garnet sand
is mixed in high pressure water, which greatly improves the cutting speed and
cutting thickness
of the water jet scalpel.
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[0004] At present, the sand-carrying cutting with water jet scalpels is widely
applied on the
ground, but requires a large space. Although the hydraulic fracturing has been
applied to mines
for a long time, the internal space of a drill hole is restricted by the
diameter of the drill hole,
when hydraulic slotting is carried out inside the drill hole, almost no sand
is carried, and only
high energy impact of high pressure water is used to break the coal rock.
Consequently, the
efficiency is low, the fracture depth caused by the impact is insufficient,
and the directional
effect of the directional hydraulic fracturing is poor; secondly, short
nozzles of a conventional
hydraulic slotting drill bit are arranged on a concentric circle, and the high
pressure water
cannot accumulate enough energy in the nozzles and is insufficient in energy
when being
ejected from the drill bit to limit the destruction to the coal and rock mass,
so that the slotting
depth is insufficient, the directional fracturing effect is poor, and the
engineering problems
such as directional cutting of a hard roof cannot be thoroughly solved.
100051 It is well known that the cutting speed and cutting radius of the sand-
carrying water jet
is much higher than those of the sand-free water jet. There are two ways to
produce sand-
carrying high pressure water jet: the first one is pre-mixing, that is, after
high pressure water
and abrasive (sand) are mixed, the water-sand mixture passes through a high
pressure pipeline
to reach nozzles and is directly ejected by the nozzles to cut a material; the
second one is post-
mixing, where after sand in a sandbox is sucked into nozzles by using the
siphon phenomenon
generated by high pressure water at the nozzles, and mixed with the high
pressure water, the
mixture is ejected by the nozzles to cut a corresponding material. The water-
sand mixture
produced by the pre-mixing seriously wears the high pressure pipeline along
the way, and the
nozzles are easily blocked by the sand. Consequently, the conventional
hydraulic slotting drill
bit is rarely used; and the post-mixing requires a large space to complete,
and the conventional
hydraulic slotting drill bit does not have such a condition and cannot realize
such a function.
SUMMARY OF THE INVENTION
Technical Problem
[0006] To overcome the existing deficiencies, the present invention provides a
self-carrying
abrasive type hydraulic slotting drill bit. The drill bit can greatly improve
the cutting capability
of water jet, the cutting capability is remarkably improved, the cutting speed
is also greatly
improved, more energy is obtained by the high pressure water jet, the slotting
range is increased,
and the directional fracturing effect of a drill hole is better, so that the
quantity of drill holes
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arranged on a working face is reduced, and the cost is lowered.
Technical Solution
[0007] The technical solution adopted by the present invention is as follows.
A self-carrying
abrasive type hydraulic slotting drill bit includes a drill bit and cutting
heads installed on the
periphery of the top of the drill bit, the drill bit is composed of a drill
bit outer wall and a drill
bit cavity, and a low pressure cooling water flow system and high pressure
cutting water flow
system, a high pressure water-sand mixture production and abrasive adding
system, and a high
and low pressure water shunt control system are arranged in the drill bit
cavity; a water flow
channel is formed in the center of the bottom of the drill bit; two low
pressure water channels
connecting from the water flow channel to the top of the drill bit constitute
the low pressure
cooling water flow system, and the two low pressure water channels are
arranged
symmetrically with the center line of the water flow channel as a symmetry
axis; a high pressure
water inlet channel and a high pressure water buffer channel are sequentially
connected to
constitute an eccentric high pressure water pipe, a channel nozzle is arranged
on the high
pressure water buffer channel, two eccentric high pressure water pipes
connecting from the
water flow channel to the drill bit outer wall constitute the high pressure
cutting water flow
system, the eccentric directions of the two eccentric high pressure water
pipes are opposite,
two high pressure water inlets are identical in height, and two high pressure
water outlets are
high and low respectively; the high pressure water inlets are above low
pressure water inlets,
and the plane in which the low pressure cooling water flow system is located
is perpendicular
to the plane in which the high pressure cutting water flow system is located;
the high pressure
water-sand mixture production and abrasive adding system includes high
pressure water sand-
sucking channels and a sand storage box, the sand storage box is arranged
above the water flow
channel, and the high pressure water buffer channels are connected to the sand
storage box by
using the high pressure water sand-sucking channels; the high and low pressure
water shunt
control system includes a hole sealing baffle, a pressure control steel ball,
an inner control wall
and a pressure control spring, wherein the inner control wall is in contact
with the drill hole
inner wall of the water flow channel, the inner control wall is provided with
holes
corresponding to the high pressure water inlets and the low pressure water
inlets in shape and
position, the hole sealing baffle is arranged on the inner control wall below
the low pressure
water inlets, the pressure control steel ball is above the hole sealing
baffle, and the pressure
control spring is connected to the pressure control steel ball and the inner
control wall at the
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top end of the water flow channel.
Advantageous Effect
[0008] Compared with the prior technology, the self-carrying abrasive
hydraulic slotting drill
bit of the present invention has the advantages that the high pressure cutting
water flow system
is composed of two eccentric high pressure water pipes connecting from the
water flow channel
to the drill bit outer wall, thereby providing a longer water jet channel,
increasing the energy
of high pressure water reaching the water outlets, and improving the slotting
effect; in addition,
the eccentric high pressure water pipes are staggered up and down and
eccentric left and right,
which provides a circumferential force for the drill bit and can accelerate
circumferential
slotting; a sand storage box is added to provide a sand storage space, so that
the cutting range
and cutting speed of the high pressure water jet carrying sand are increased;
the sand-sucking
channels cause the sand sucked into the high pressure water via negative
pressure produced by
the high pressure water, thereby achieving the effect of automatically sucking
the sand; the
high and low pressure water shunt control system is arranged, wherein pressure
control
components (a pressure control steel ball and an inner control wall) can be
moved as a whole
to control a conversion of high pressure water and low pressure water, wherein
the pressure
control steel ball can reduce the stress concentration of the high pressure
water entering the
high pressure water inlets and prolong the service life thereof, and the
pressure control spring
is connected to the pressure control components to control a relationship
between the pressure
and the displacement of the pressure control components so as to control the
conversion of high
pressure water and low pressure water; and the spatial joint arrangement of
high pressure water
channel and low pressure water channel improves the overall efficiency of the
apparatus, and
achieves reasonable use of the drill bit cavity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The following further illustrates the present invention with reference
to the
accompanying drawings and embodiments.
[0010] Fig. 1 is an overlook perspective according to an embodiment of the
present invention.
[0011] Fig. 2 is a cross-sectional view taken along line I-I of Fig. I.
[0012] Fig. 3 is a cross-sectional view taken along line II-II of Fig. I.
[0013] In the drawings, 1, drill bit outer wall; 2, sand supply channel; 3,
sand supply hole; 41,
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upper high pressure water sand-sucking channel; 42, lower high pressure water
sand-sucking
channel; 51, upper high pressure water inlet channel; 52, lower high pressure
water inlet
channel; 61, upper high pressure water buffer channel; 62, lower high pressure
water buffer
channel; 71, upper high pressure water outlet; 72, lower high pressure water
outlet; 81, upper
channel nozzle; 82, lower channel nozzle; 9, sand storage box; 10, low
pressure water channel;
11, pressure control spring; 12, inner control wall; 13, pressure control
steel ball; 14, water
flow channel; 15, hole sealing baffle; 16, total water inlet; 17, low pressure
water inlet; 18, low
pressure water outlet; 191, upper high pressure water inlet; 192, lower high
pressure water inlet;
and 20, cutting head.
DETAILED DESCRIPTION OF THE INVENTION
[0014] In order to make the objective, technical solution and advantages of
the present
invention clearer, the following clearly and completely describes the
technical solution in the
embodiments of the present invention with reference to the accompanying
drawings in the
embodiments of the present invention. Apparently, the described embodiments
are only part of
the embodiments of the present invention, not all of the embodiments of the
present invention.
All other embodiments obtained by those of ordinary skill in the art based on
the embodiments
of the present invention without any creative effort shall fall within the
protection scope of the
present invention.
[0015] Fig. 1 to Fig. 3 are structural diagrams according to a preferred
embodiment of the
present invention. A self-carrying abrasive type hydraulic slotting drill bit
includes a drill bit
and cutting heads 20 installed on the periphery of the top of the drill bit,
the cutting heads 20
are apparatuses for cutting coal mass or rock mass, the drill bit is composed
of a drill bit outer
wall 1 and a drill bit cavity, the drill bit outer wall 1 supports the overall
shape of the drill bit,
the drill bit cavity provides a working space for each internal system, and a
low pressure
cooling water flow system and high pressure cutting water flow system, a high
pressure water-
sand mixture production and abrasive adding system, and a high and low
pressure water shunt
control system are arranged in the drill bit cavity.
[0016] A water flow channel 14 is formed in the center of the bottom of the
drill bit, and the
water flow channel 14 is formed by extending a total water inlet 16 where
total water flows
into the drill bit by a distance; two low pressure water channels 10
connecting from the water
flow channel 14 to the top of the drill bit constitute the low pressure
cooling water flow system,
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the low pressure water channels 10 are channels for low pressure water from
the inside of the
drill bit to the outside, and the two low pressure water channels 10 are
arranged symmetrically
with the center line of the water flow channel 14 as a symmetry axis; a high
pressure water
inlet channel and a high pressure water buffer channel are sequentially
connected to constitute
an eccentric high pressure water pipe, a channel nozzle is arranged on the
high pressure water
buffer channel, the high pressure water buffer channel is a channel for high
pressure water to
accumulate energy, the channel nozzle is an apparatus for ejecting high
pressure water, two
eccentric high pressure water pipes connecting from the water flow channel 14
to the drill bit
outer wall 1 constitute the high pressure cutting water flow system, the
eccentric directions of
the two eccentric high pressure water pipes are opposite, a high pressure
water inlet is at a
position where the high pressure water enters a high pressure water inlet
channel, a high
pressure water outlet is at a position where the high pressure water is
ejected from the drill bit,
the two high pressure water inlets are identical in height, and the two high
pressure water outlets
are high and low respectively, that is, the upper high pressure water outlet
71 is higher than the
lower high pressure water outlet 72; a low pressure water inlet 17 is at a
position where the low
pressure water enters a low pressure water channel, a low pressure water
outlet 18 is at a
position where the low pressure water is in contact with the outside through
the low pressure
water channel 10, the high pressure water inlets are above the low pressure
water inlets 17, and
the plane in which the low pressure cooling water flow system is located is
perpendicular to
the plane in which the high pressure cutting water flow system is located;
specifically, the two
eccentric high pressure water pipes constituting the high pressure cutting
water flow system
are respectively an upper eccentric high pressure water pipe and a lower
eccentric high pressure
water pipe; an upper high pressure water inlet channel Si, an upper high
pressure water buffer
channel 61 and an upper channel nozzle 81 are sequentially connected to
constitute the upper
eccentric high pressure water pipe; a lower high pressure water inlet channel
52, a lower high
pressure water buffer channel 62 and a lower channel nozzle 82 are
sequentially connected to
constitute the lower eccentric high pressure water pipe; an upper high
pressure water inlet 191
and a lower high pressure water inlet 192 are identical in height, and the
upper high pressure
water inlet 191 is higher than the lower high pressure water inlet 192; in
this way, the upper
eccentric high pressure water pipe and the lower eccentric high pressure water
pipe are
staggered up and down and eccentric left and right, thereby increasing the
buffer length of the
high pressure water jet, increasing the speed at which the water jet reaches
the outlet, and
improving the penetration and destructive force of the water jet.
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[0017] The high pressure water-sand mixture production and abrasive adding
system includes
high pressure water sand-sucking channels and a sand storage box 9, the sand
storage box 9 is
arranged above the water flow channel 14, the sand storage box 9 provides a
storage space for
sand, the high pressure water buffer channels are connected to the sand
storage box 9 by using
the high pressure water sand-sucking channels, specifically, the upper high
pressure water
buffer channel 61 is connected to the sand storage box 9 by using an upper
high pressure water
sand-sucking channel 41, and the lower high pressure water buffer channel 62
is connected to
the sand storage box 9 by using a lower high pressure water sand-sucking
channel 42; the high
pressure water sand-sucking channels connect the high pressure water buffer
channels with the
sand storage box 9, when the high pressure water passes through the joints of
the high pressure
water sand-sucking channels and the high pressure water buffer channels, the
produced
negative pressure sucks sand into the high pressure water through the
channels, and therefore
the high pressure water jet is mixed with the abrasive (sand) at the nozzles
to form a water-
sand mixture, thereby improving the penetration and destructive force of the
high pressure
water and improving the cutting capability of the water jet.
[0018] The high and low pressure water shunt control system includes a hole
sealing baffle 15,
a pressure control steel ball 13, an inner control wall 12 and a pressure
control spring 11,
wherein the pressure control spring 11 is a component which controls water
pressure such that
the low water pressure coordinates with the high water pressure, the inner
control wall 12 is in
contact with the drill hole inner wall of the water flow channel 14, the inner
control wall 12 is
provided with holes (not shown) corresponding to the high pressure water
inlets and with
holes 121 corresponding to the low pressure water inlets in shape and
position, and when the
pressure reaches a degree, the holes are connected to the corresponding
channel inlets
respectively, so that the water under different pressures flows into
respective channels via
the inner control wall 12; the pressure control steel ball 13 can control a
flow direction of
the high pressure water, thereby reducing the stress concentration and
prolonging the
service life of the apparatus; the hole sealing baffle 15 is arranged on the
inner control
wall 12 below the low pressure water inlets 17, the pressure control steel
ball 13 is above
the hole sealing baffle 15, and the pressure control spring 11 is connected to
the pressure
control steel ball 13 and the inner control wall 12 at the top end of the
water flow channel 14;
when the pressure reaches a degree, the pressure control steel ball 13, the
inner control wall
12 and the pressure control spring 11 rise, the baffle blocks part of the
water flow channel 14
to control the position of the water entering the channels, and the
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inlet of the water flow is adjusted through different water pressures, so that
the flow directions
of the high pressure water and the low pressure water are controlled.
[0019] In this embodiment, the low pressure cooling water flow system is
formed by
connecting a horizontal section with a vertical section, the other end of the
horizontal section
is connected to the low pressure water inlet 17, and the other end of the
vertical section is
connected to the low pressure water outlet 18. The high pressure water inlet
channel is a curved
eccentric pipeline, and the high pressure water buffer channel is a
horizontally contracted
pipeline having a diameter smaller than those of the high pressure water inlet
channel and the
channel nozzle.
[0020] As a further optimization design of this embodiment, the high pressure
water-sand
mixture production and abrasive adding system further includes a sand supply
channel 2, the
upper end face of the sand storage box 9 is provided with a sand supply hole
3, and the sand
supply channel 2 is from the sand supply hole 3 to the top end of the drill
bit. The sand supply
hole 3 serves as a position for sand to enter the apparatus, and the sand
supply channel 2 is a
channel for supplying sand. In the presence of the sand supply channel 2, the
abrasive (sand)
can be added multiple times, so that the drill bit can be reused multiple
times.
[0021] The working process of the three systems according to the embodiments
of the present
invention is as follows:
[0022] 1) Low-pressure cooling water flow system and high pressure cutting
water flow system:
the initial injected water is low pressure water because the water pressure is
gradually increased,
part of water flows through the low pressure water channels 10 and the high
pressure water
inlet channels to cool the drill bit at the initial drilling stage, and at
this time, the low pressure
control components do not ascend and the pressure control spring 11 is not
compressed due to
the low pressure; when a drill hole is drilled to a certain position, the high
pressure water is
required for hydraulic slotting, the water pressure at this time increasingly
rises, and the
pressure control components continuously ascend as the pressure received by
the pressure
control spring 11 increases; after a certain pressure is reached, the high
pressure water impacts
the pressure control steel ball 13, so that the water is shunt to the two high
pressure water inlet
channels.
[0023] 2) High and low pressure water shunt control system: during the cooling
process, water
mainly flows through the low pressure water channels, the high pressure water
enters the
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channels to assist the cooling, and the water reaches the inside of the drill
bit through the total
water inlet 16; the low water pressure cannot cause the pressure control
components to ascend
and the pressure control spring 11 to compress, so the water enters from the
low pressure water
inlets 17 to the low pressure channels and then reaches the drill bit to cool
the drill bit, and
meanwhile, the low pressure water also enters from the high pressure water
inlets to the high
pressure water inlet channels and flows through the channel nozzles; the high
pressure water
enters from the high pressure water inlets to the high pressure water inlet
channels, flows
through the high pressure water buffer channels and the channel nozzles, and
reaches the drill
bit outer wall 1 to cool same; more importantly, during the drilling process
of the drill bit,
pressure water always flows out from the high pressure water channel nozzles
to prevent
drilling cuttings produced during the drilling process from blocking the two
channel nozzles;
when the pressure water is high pressure water, the high pressure water flows
from the total
water inlet 16 to the high pressure water inlets, then reaches the high
pressure water inlet
channels, and flows through the high pressure water buffer channels, and the
high-energy water
jet is ejected from the high pressure water outlets through the channel
nozzles to carry out
hydraulic slotting.
[0024] 3) High-pressure water-sand mixture production and abrasive adding
system: at the
beginning, sand is injected through the sand supply hole 3, and the sand
enters the sand storage
box 9 through the sand supply channel 2; when high pressure water flows, the
negative pressure
produced by the high pressure water sucks the sand into the high pressure
water, so that the
sand cuts the coal (rock) mass together with the high pressure water; after
the sand in the sand
storage box 9 is used up, sand is supplied through the sand supply hole 3, so
that the apparatus
can be reused multiple times.
100251 The beneficial effects of the present invention are as follows:
[0026] 1. The apparatus is designed with eccentric jet pipes (for example,
eccentric high
pressure water pipes) to provide longer water jet channels, so that more
energy is obtained by
the high pressure water jet, the slotting range is increased, the directional
fracturing effect of
drill holes is better, the directional fracturing range of a single drill hole
is larger, the quantity
of drill holes arranged on a working face is reduced, the cost is reduced,
meanwhile, the
directional fracturing effect of a hard roof is better, the fracturing
position of the roof is enabled
to fracture along the designed fracture line when the hard roof is
directionally fractured, and
therefore better engineering effects, such as directional top cutting and
pressure relief in a
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roadway near a gob, can be achieved.
100271 2. A sand storage box 9 is designed in the drill bit, and sand is
sucked into the water jet
through the negative pressure produced by the high pressure water jet nozzles
to increase the
cutting capability and cutting speed of the water jet. Cutting hard rock in
the limited space of
a drill hole by the pure high pressure water jet (no abrasive such as the sand
is added) is difficult.
The pure high pressure water jet can cut only some soft rock strata and coal
seams within a
small range, and therefore is limited in cutting capability and low in cutting
speed. After the
sand storage box 9 is integrated in the drill bit, the abrasive (sand) can be
added in the high
pressure water, which can greatly improve the cutting capability of the water
jet, cut hard rock
or even steel plates, remarkably improve the cutting capability and greatly
improve the cutting
speed.
100281 3. The sand storage box 9 is supplied with sand through a special
supply hole, and the
capacity of the sand storage box 9 is sufficient for hydraulic slotting of a
drill hole. When a
drill hole is drilled to a predetermined position, after the hydraulic
slotting is performed, the
drill bit is withdrawn, and sand is fully fed to the inside of the drill bit
through a special sand
supply channel for hydraulic slotting of a next drill hole. After the special
sand supply channel
is designed, the hydraulic slotting drill bit can be reused multiple times, so
that the practical
value of the slotting drill bit is improved.
[0029] 4. The pressure is controlled through a pressure control system. When
the pressure is
low, only the cooling operation is performed; when the pressure is high, the
pressure control
components (the inner control wall 12 and the pressure control steel ball 13)
compress the
pressure control spring 11 due to the pressure increase, the pressure control
components ascend,
the lower low pressure water inlets 17 are blocked by the inner control wall
12 of the control
component, the water only enters the high pressure water channels from the
high pressure water
inlets and reaches the high pressure water nozzles, and the high pressure
water is ejected from
the high pressure water outlets through the buffer channels, wherein the
pressure control steel
ball 13 can change the flow direction of the water to reduce the stress
concentration.
[0030] Described above is only a preferred embodiment of the present
invention, and the
present invention is not limited thereto in any form. Any simple modifications
and equivalent
changes made to the embodiment according to the technical essence of the
present invention
shall fall within the protection scope of the present invention.
