The invention concerns an apparatus with a primer and a detonator for insertion into a charging hose for inserting bulk explosives in a whole. A method for the use of the apparatus in connection with the charging of bulk explosives in a whole and a charging device for charging with the apparatus is also described.
When blasting rock cavities and tunnels in rock, it is common to bore holes into the rock and then to place explosives, preferably bulk explosives, into the borehole along with the primer and detonator, for succeeding ignition of the explosive. The explosive, the primer and the detonator are often run into the bore hole by means of specific devices or systems designed for the purpose. The explosive can be in powder, pasta/gel, slurry or emulsion form.
The holes may have various directions, from horizontal to vertical/upwards directed. Of mainly safety reasons it is often desired to be able to perform the charging at a certain distance from the borehole. The reason may be, that the hole is difficult to access, that the area above/in front of the hole can represent danger and that the working operation in this way can be performed faster and safer.
Various systems for remote placement of the bulk explosives in boreholes are known. These systems comprise feeding systems for hoses or sticks with bulk explosives- and branch pipe for insertion of necessary primer with detonator. The hose or the sticks usually have a diameter of between 1 cm and 15 cm usually made of, a flexible material, for instance rubber or plastic. A primer with detonator may be pushed in front of the hose with bulk explosives, to the place to be charges, usually to the bottom of the borehole. The primer is often packed in a sort of cartridge, or skin, to form a “sausage like” unit the detonator is pushed into.
Examples of prior art are shown in the Swedish publications 7506593-8 and 465 566.
SE-465 566 shows a feeding device for flexible hoses or sticks and a charging unit. The feeding device comprises wheels or bands for conveying the hose or sticks and a branch pipe with feeding unit for inserting a primer with detonator.
SE 7506593-8 shows an apparatus for the insertion of a charge in a borehole. The apparatus comprises an unit with fuse/wire spooled around the apparatus.
In these publications it is shown that a primer with a detonator is carried ahead of a feeding hose and is in this way pushed into a borehole. However, it happens that in some cases and attempted charging must be disrupted—and the items must be pulled out again. This will be difficult with the apparatuses shown in the prior art. Furthermore, it can be a problem that the detonator “falls' into the borehole when this is inclined downwards or vertical. Such holes are often filled with water or other fluids, such that the primer with detonator becomes surrounded by water, outside the bulk explosives that are filled, and this may effect the ignition of the bulk explosive.
The above mentioned and other disadvantages relating to the charging of boreholes are omitted with the present invention. The invention concerns an apparatus adapted to include primer with detonator intended to be provided in a borehole by means of a charging hose for the filling of explosives into the hole. The apparatus comprises a cartridge-shaped plug adapted to be pushed into the opening of the charging hose and to be releasable held in the charging hose, and to be freed or released from the charging hose when the explosives are made to flow out of the charging hose. The apparatus may have an open and a closed end, and the primer will then normally be filled through the open end, and be placed in the charging hose with the closed end first. The detonator is placed in the apparatus and the primer through the open end. Alternatively, a plug or seal in the open end with an opening for the detonator can be formed. The detonator should preferably be protected by the apparatus when this is put in place.
The cartridge-shaped plug does not necessary need to seal the outlet of the charging hose, because the volume flow and the viscosity of the bulk explosives are such that the bulk explosives will apply a sufficient force on the plug to push it out, without the plug necessarily sealing the outlet of the charging hose. The cartridge is releasably secured in the charging hose due to the friction between the tube and the cartridge, and this friction force is what is exceeded when the bulk explosives flow out of the charging hose. The bulk explosives can be pumped into the charging hose, or can flow out due to gravity.
Furthermore, the invention comprises a method for providing a primer with detonator in a hole to be blasted by means of an apparatus adapted to incorporate primer with detonator to be provided in a borehole by means of a charging hose for the filling of explosives in the hole where the primer and detonator is inserted in a cartridge shaped plug, where the plug is pushed into the outlet of the charging hose and is releasable secured in this during the insertion of the hose in the hole, and where the plug is released from the charging hose by the bulk explosives when this is lead out of the charging hose.
The invention also describes a method be using a charging device comprising a feeding unit, a branch tube with an inlet section and an outlet section connected with a deviated section, a transport channel, a guiding tube and a charging house, where the feeding unit is adapted to feed the charging hose through the guiding tube and into the outlet section of the branch pipe comprising the following steps:
Inserting the charging hose into the guiding tube by means of the feeding unit such that one end of the charging hose is placed in the guiding tube, inserting the apparatus into the transport channel, conveying the apparatus through the transport channel and into the branch pipe forward to a stopping device placed in the outlet section of the branch pipe, feeding the charging hose such that the charging hose is guided outside the apparatus, and releasing the stopping device such that the charging hose with the apparatus can be conveyed out of the outlet section of the branch pipe and into the bottom of the hole.
The invention also comprises a charging device for charging bulk explosives into holes, where the charging device comprises a feeding unit for feeding a charging hose, a guiding tube for guiding the charging hose, and a transport channel for inserting the apparatus into a branch pipe. The charging device furthermore comprises a stopping device holding the apparatus in an outlet section of the branch pipe until the charging hose is led to the outside of the apparatus.
The apparatus is filled with a primer and a detonator, known in the art. The apparatus can manually or automatically be inserted in the end of the charging hose, before this is led into a hole, usually a borehole or blasting hole in rock. Preceding the insertion of the charging hose in the hole, bulk explosives are led out of the charging hose and the bulk explosives thereby pushes the apparatus out of the charging hose, such that this stays in the borehole surrounded by bulk explosives. The bulk explosives continues to flow out of the charging hose while this is withdrawn through the hole, and the hole is filled with a predetermined amount of bulk explosives. The detonator communicates in a ordinary way by means of wire or fuse with device well known in the art for igniting the detonator.
This charging device may appear similar to the one described in the Swedish publication SE-465 566, but the device according to the present invention also comprises a stopping unit in the branch pipe (denoted as guiding tube 50 in the Swedish publication). The branch pipe comprises two substantially straight areas connected with a curvature or bend, such that the two areas form an angle in relation to each other. A guiding tube is connected with the branch pipe in this curvature such that the guiding tube forms a substantially straight extension of the one substantially straight area and an angle with the other substantially straight area. The stopping device is provided in the straight area of the branch pipe forming an extension of the guiding tube, such that the device can be “parked” against the stopping device after insertion in the branch pipe. The stopping device can be controlled in various ways, as long as it stops the apparatus until the charging hose is led over the apparatus. A counter for the charging hose can for instance be used to indicate when this is placed over the apparatus, and when the charging hose is in a position that accepts the conveying of the apparatus. This position is in an area of the guiding tube before the transition to the branch pipe. The stopping device can be controlled electrically, pneumatically or hydraulically. Photocells or other means can be used to sense and control this process.
The invention is more closely described below with reference to the accompanying drawings, where:
Below follows an embodiment of the invention with reference to the accompanying drawings.
The stopping device 19 comprises a locking pin 12 in which the apparatus A is held against and stopped and that holds the apparatus A until the charging hose is led on the outside of the apparatus A. The stopping device 19 is shown purely mechanically, in that a wheel 13 is displaced by the charging hose 21 such that the locking pin 12 releases the apparatus A and the ready and charged” hose can be led out of the outlet section 18 of the branch pipe. However, the stopping device 19 can be controlled in other ways as long as it stops the apparatus A until the charging hose 21 is led over the apparatus A. A counter (not shown) for the charging hose 21 may for instance be used to denote when this is placed over the apparatus A and when the charging hose 21 is in a position that accepts conveying of the apparatus A. This position is in the area 10 of the guiding pipe 15 in front of the transition to the branch pipe 17, 18. Locking pin 12 may alternatively be controlled electrically, pneumatically, hydraulically or a combination for these. Photocells or other means can also be used to sense and control this process. The guiding tube 15 has preferably a reasonably small gap in relation to the charging hose 21, to prevent to much pressurized air to leak out if the apparatus A is to be conveyed to the stopping device 19 by pressurized air. A seal may of course also be provided if necessary. However, the apparatus A may be conveyed in other ways, making this uncritical. Stemming or driven rolls are examples of such methods. Reference numeral 14 shows a delivery channel for the apparatus A to the branch pipe 16, 17, 18. This results in the charging hose being charged from a substantial distance (tenths of meters) and this has important advantageous in relation to safety.
An example of a method according to the invention for charging boreholes with the charging device shown on
The shown examples are only intended to illustrate embodiments of the invention and the invention is only delimited by the enclosed claims.
Number | Date | Country | Kind |
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2000 3438 | Jul 2000 | NO | national |
Filing Document | Filing Date | Country | Kind |
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PCT/NO01/00276 | 6/29/2001 | WO |