US3005373A

US3005373A - Vehicle mounted dispenser for charging explosive mixtures in blast holes

Info

Publication number: US3005373A
Application number: US713637A
Authority: US
Inventors: Jr William R Ransom
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1958-02-06
Filing date: 1958-02-06
Publication date: 1961-10-24
Anticipated expiration: 1978-10-24

Description

Oct. 24, 1961 r w, R. RANSOM, JR

VEHICLE MOUNTED DISPENSER FOR CHARGING EXPLOSIVE MIXTURES IN BLAST HOLES Filed Feb. 6. 1958 3 Sheets-Sheet 1 "wen/rm WILL/AM x2. PANSOM, 42'.

Attorney Oct. 24, 1961 w. R. RANSOM, JR 3,

VEHICLE MOUNTED DISPENSER FQR CHARGING EXPLOSIVE MIXTURES m BLAST moms Filed Feb. 6, 1958 '3 Sheets-Shaet 2 W/LL/AM z AMA/$0M, .12.

Attorney Oct. 24, 1961 w RANSQM, JR 3,005,373

VEHICLE MOUNTED DISPENSER FOR CHARGING EXPLOSIVE MIXTURES IN BLAST HOLES Filed Feb. 6, 1958 3 Sheets-Sheet 3 William R. Ransom, Jr., Rogers City, Mich, assignor to United States Steel Corporation, a corporation of New Jersey Filed Feb. 6, 1958, Ser. No. 713,637

6 Claims. (Cl. 86-20) This invention relates to an apparatus for charging explosives in blast holes which, as indicated, is in the form of a dispenser mounted on a truck or other traction vehicle It relates more particularly to an apparatus for charging blast holes with an explosive mixture of ammonium nitrate and a combustible material, preferably a liquid hydrocarbon, in, such manner that a uniform dispersion of the combustible material in the ammonium nitrate is obtained. q

Fertilizer grades of ammonium nitrate have explosive properties that render it suitable for limestone or other rock quarrying operations and are of course considerably less expensive than commercial ammonium nitrate ex plosives such as ammonia dynamite. As distinguished from these commercial and more expensive explosive materials, it will be understood for purposes of definition that the use of the term ammonium nitratefhereinafter refers to the less expensive material commonly sold and used as fertilizer, and that the term granular as applied to'this' material is intended as generic to the various particle sizesand shapes that are produced by different processing, operations and are designated commercially by the terms flake, prills, crystals, granular, grained, etc. The explosive properties of this material are further known to be improved by the addition thereto or" a combustible material, such as carbon, in an amount that will combine'with the excess oxygen in the ammonium nitrate and thereby increase the energy released upon detonation. However, to obtain the maximum benefit from an addition for this purpose,.the combustible material must be uniformly dispersed through the nitrate andin an accurately proportioned amount. This has been a source of considerable trouble in preparing and charging explosive mixtures of those materials in ,blast holes. One of the principal objects of this invention is to provide a dispenser which will facilitate the charging of blast holes with explosivemixtures of the character mentioned above. further and related object is to provide an apparatus that will accurately proportion the ammonium nitrate and the combustible material, and which will efiect a uniform dispersion of the combustible material through the ammonium nitrate. A still further object is to provide an apparatus of this character in which the combustible material is a liquid hydrocarbon that is mixed with and uniformly dispersedthrough the ammonium nitrate by being sprayed into its path of travel as it gravitates through a charging spout into a blast hole.

, In many cases it may be necessary to provide-the blast hole with a lining to prevent seepage water from accumulating therein and interfering with the blasting opera tion. This invention accordingly has as an additional object the provision of an apparatus which is particularly adapted to the installation in a blast hole of a lining in the form of a sleeve or tube of water impervious material. Other objects and advantages of the invention will become apparent from the following description.

In the drawings there is shown a preferred embodiment of the invention. In this showing:

FIGURE 1 is a side elevational view of an explosive charging apparatus constructed in accordance with the principles of this invention which is shown in its operative assembled position on the chassis of a truck or other traction vehicle;

' United States Patent is particularly adapted for the purpose of charging blast Patented Oct. 24, 19 61 FIGURE 2 is a plan view of the apparatus shown in FIGURE 1;

FIGURE 3 is an end view taken in the direction looking from the right of FIGURES l and 2;

FIGURE 4 is an enlarged elevational view of the charging spout shown in FIGURE 3 with a portion thereof broken away along its, vertical center line and shown in section;

FIGURES 5 and 6 are sectional views taken respectively along the lines V-V and VI-VI of FIGURE 4; and i FIGURE 7 shows somewhat diagrammatically the manner in which the apparatus is used to linea blast hole with a sleeve or tube of water impervious material and tocharge an explosive mixture therein. As indicated above, the apparatus of this inventio holes withan explosive mixture of granular ammonium nitrate and a combustible material such as fuel oil or other liquid hydrocarbons. Such apparatus, as shown in FIGURES 1-3, is comprised of a vertically extending spout I that is centered with respect to a blast hole in a manner to be described. Mixture of the materials is etiected during their movement through the spout by spraying fuel oil into the ammonium nitrate which is supplied from a chute 2 and hopper 3 at a regulated rate in a manner to be described; Fuel oil is injected into the path of movement of the granular material through the spout 1 by a spray 4 which receives the fuel oil under pressure from a supply line 5. A solenoid actu ated shut-off valve 6 controls thesupply of fuel oil through the line 5 from a reservoir or other source (not shown), and a manually adjustable control valve 7 regulates its rate of flow. The relative proportions of these. materials in the explosive charge are determined byregulating their respective rates of feed through the spout l.

The apparatus is assembled and supported on .the chassis 8 of a truck or other traction vehicle 9 by a frame 10 for swinging movement about the axis of a vertical pivot pin 11 to provide for adjustment of the position of the spout 1 with respect to a blast hole over which it is being centered. -A horizontal platform 12 that extends inwardly from one edge of the hopper 3 which is also mounted on the frame 10 furnishes a convenient support on which bags of ammonium nitrate can be opened by an operator and poured into the hopper 3.

The material filled in the hopper 3 in this manner is delivered to the chute 2 through an opening 13 which is under the control of a doorclosure 14 mounted by guides 15 for sliding movement between open and closed positions. An actuating link 16 and operating lever17 are provided for moving the closure 14 between its open and closed positions.

The chute 2 extends, angularly outwardly and down- Wardly from the hopper 3 as shown in FIGURE 1 and is comprised of

telescoped sections

20 and 21; The

a chute section 20 has itsupper end secured to the hopper 1 can be adjusted in a horizontal direction with respect to a blast hole without moving the traction vehicle 9; The chute section 20 further is formed in two parts which are connected by a short section 23 of flexible material intermediate its ends that provides for adjustment ofthe angular position of the chute section 2.1 in which the lower part 24 of chute section 29 is telescopically received.

A cable 25 supports the chute section 21 in the angular position shown in FIGURE 1 and is reeled over a pulley 1 26 which is suspended from a frame 27 supported onthe I blast hole.

ment thereof increases the rate of flow.

While adjustment of the angular position of the chute section 21 provides a regulation of the rate of flow of granular material therethrough, a valve damper arrangement of the type shown in FIGURES 4-6 is preferred for this purpose. As shown in these views, the upper section '30 of the spout 1 has'a rectangular shape and is' provided with hinges 31 on opposite sides thereof which provide pivotal supports for a pair of dampers 32. Pivotal downward movement of the dampers 32 is limited by stops 33 that are in the form of angles and are adjustably secured to the spout section 30 along opposite sides of the dampers32. The lower edges 34 of the dampers 32 when engaged with the angle stops 33 define a valve opening 35 through which granular material delivered to the spout 1 from the chute section 21 gravitates into a The effective size of the valve opening 35 and thereby the rate of flow of granular material therethrough is controlled by adjusting the positions of the stops 33.

Fuel oil is sprayed into the chute 1 at a regulated rate by nozzles 36 arranged in groups of three'on each of opposite sides 37 of the spout section 30. The nozzles 36-arearranged in the lower portion of the spout section 30 so that their sprays converge on a vertical plane that extends centrally of the damper valve opening 35 and in such manner that the material falling therethrough is uniformly subjected to the action of the spray and is intimately mixed with the fuel oil being injected thereby. Each of the nozzles 36 has a supply connection 38 to a manifold 39. The manifolds 39 are connected at one end to a common conduit 40 that has a T-connection 41 at its center with the fuel supply line 5.

The flow of fuel oil to the nozzles 36 through the supply line is, as mentioned above, under the control of a solenoid actuated shut-off valve 6. According to a preferred practice of the invention, the valve 6 is operated to its open position in response to flow of ammonium nitrate through the valve opening 35. For this purpose, operation of the valve 6 is controlled by a limit switch 43 which is mounted on the chute 1 and has a control button 44 arranged for operation by an actuating lever A 45 as shown in FIGURE 5. The lever 45 is secured to the projecting end 46 of the hinge pin 47 that forms part of the damper hinge 31 for the damper designated 32a in FIGURE 4. The projecting end 46 of the hinge pin 47 is bent upwardly as best shown in FIGURE 5 to provide a handle 46a which may be manually operated to actuate the lever 45 and limit switch 43. A pair of light coil springs 49- mounted on one of the chute sides 37 provide a resilient bias that operates, when no material is gravitating through the chute 21, to hold the damper 32a in a position slightly above its end stops 33 as shown in dotted lines in FIGURE 4. In this position the operating button 44 for the micro-switch 43 is not operated and the solenoid valve 6 is in its closed position interrupting the flow of fuel oil through the line 5 to the nozzles 36. When granular material is delivered to the spout through the opening 22, it falls on the damper 3211 which moves downwardly to a position determined by the location of its steps 33. This movement of the damper 32a' causes the lever 45, clamped on the hinge pin end 46, to actuate the micro-switch operating button 44. Operation of the micro-switch 43 in this. manner opens the valve 6- to supply fuel oil to the nozzles 36 at a rate that is determined by. adjustment of theregulating valve 7'.

:. .'I'he lower end of the chute. 1 is a cylindrical section 51 that has a flange 52 at its upper end which is secured by bolting to a similar flange on the bottom of the rectangular upper section 30. As best shown in FIGURE 7 a pneumatically inflatable clamping ring 53 is suspended from the flange 52 in a position about the exterior of the section 51, The ring 53 is fabricated from rubber or other expansible material that enables its being expanded by pneumatic pressure into clamping engagement with the exterior surface of the section 51. V Pneumatic pressure is admittedto the ring 53 through a supply conduit 54 under the control of a valve 55 (FIGURE 1) mounted on the traction vehicle chassis 8.

' hole 57 in an earth terrain designated by the numeral 58 which may be'limestone or other rock where quarrying operations are being performed. When it is necessary to line the hole 57 with a tube or sleeve of water impervious material to prevent the collection of seepage water therein, the tube 59 is lowered into the opening 57 and has its upper end telescoped over thetubular section 51to a position in which it is arranged in the annular space 60 about the inner surface of the clamping ring 53, asshown in FIGURE 7. The clamping ring 53 is then inflated into pneumatic sealing and clamping engagement with the upper end of the tube 59'. Air under pressure is then admitted to the interior of the spout 1 through a supply line 61 under the control of a shut-ofl valve 62. The line 61 is connected into the spout 1 through a coupling 63 attached to the lower end of the chute section 21 as shown in FIGURES. To prevent the escape of air admitted Q through the supply line 61, the chute section 21 is pro vided with a damper valve 64 that is comprised of an upper section 65 which is welded in position and a lower section 66 that has a horizontal hinge 67 along its upper edge connecting it to the lower edge of the section 65. A

pneumatic seal 68 about the periphery of the lower section 66 provides a pneumatic seal that prevents the escape of air when it is in the closed position shown in FIGURE 5'. However, the hinge 67 enables operation of the lower section 66 to open position in response to gravitational movement of ammonium nitrate through the chute section 21. When air is admitted to the chute section 21 through the supply line 61, it operates to inflate a bag or tube 59 of lining material which has its upper end attached to the spout section 51. After inflation of the liner 59 the apparatus is in condition for charging an explosive mixture of ammonium nitrate and fuel oil into a blast hole 57.

A closure 71 is provided at the upper end of the spout 1 to provide access thereto when needed. i j 1 To determine the level at which blast holes have been filled, a reel 72 of measuring tape 73 is mounted by brackets 7-4 on the spout 1. The tape'73 extends through a slot 75 in the spout 1 and is reeled over guide pulleys 76. It has a weight 77 attached to its lower end so that it may be lowered through the spout section 51 to thereby provide an operator with information concerning the depth to which the blast hole 57 has been filled.

' A typical charging operation is effected by driving the truck 9 to a position in which the spout 1 is arranged over a blast hole to be charged with explosive. Final cen tering adjustment of the spout 1 with respect to such hole is obtained by swinging the frame 10 about the pivot 11 and by adjusting the telescopedposition of the chute section 21 on the lower end 24 of the chute section 20. Thereafter bags of ammonium nitrate are opened on the platform 12 and poured into the hopper 3 until it contains a sutficient amount of ammonium nitrate for the blast hole to be charged. The lever 17 is then operated to slide the door closure 14 to a position uncovering the opening 13 so that the ammonium nitrate in the. hopper 3 may gravitate through the chute 2 into the spout 1. As the material moves downwardly through the chute-1,-

' it actuates the damper 32a against the action of the bias ing springs 49 as explained above, and the lever 45 is turn energizes the solenoid valve 6 to its open position and to thereby deliver a supply of fuel oil to the spray nozzles 36 at a rate controlled by the regulating valve 7. In this manner, the ammonium nitrate moving through the meter opening 35 at a rate determined by the size of such opening is intimately mixed with a predetermined quantity of fuel oil. The resulting mixture gravitates through the lower spout section 51 into a blast hole over which it has been centered as explained above.

While the arrangement of hopper 3 and chute 2 as shown in the drawings furnishes a convenient means for delivering ammonium nitrate to the spout 1, it will be understood that other conveyor arrangements such as variable speed screw conveyors and the like may be used for this purpose. In addition, it will be apparent that the substitution of such other conveyor arrangements will eliminate the necessity of adjustable valve dampers 32 for regulating the rate of flow through the spout 1, and that actuation of the switch 43 to control the supply of fuel oil or other combustible material can be made responsive to other damper arrangements, for example, the damper 66, that are actuated by the ammonium nitrate as it flows through the chute 2 or spout 1. Moreover, and while the foregoing describes a modification that uses fuel oil as the combustible material, it will also be understood that other liquid hydrocarbons such as nitroparaffins, 2 nitro-propane or nitro-methane, for example, may be used instead. In these and other respects, it will be further understood that the drawings show one embodiment of the invention and that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. An apparatus for filling an explosive charge of granular material in a blast hole comprising a vertically extending spout, a support for said spout including means for centering its position over a blast hole, means for feeding granular material to said spout for gravitational movement therethrough into a blast hole, a damper valve in the path of gravitational movement of said material through said spout, means for adjusting the position of said valve to regulate the rate of How of said material, said valve having a pivotal support for limited movement in a direction away from its adjusted position and a spring biasing its movement in said direction, said valve being movable to its said adjusted position against the action of said biasing spring in response to movement of granular material through said spout, and spray means under the control of said damper valve for injecting a spray of another material into the path of gravitational movement of said granular material through said spout upon movement of said valve thereby to its said adjusted position, said spray means including a control valve, a solenoid for actuating said control valve, and a limit switch operated by said damper valve controlling the operation of said solenoid.

2. An apparatus for filling an explosive charge of granular material in a blast hole comprising a vertically extending spout, a hopper for supplying said granular material to said spout for gravitational movement therethrough, a traction vehicle on which said spout and hopper are mounted, means including said vehicle for centering the position of said spout over a blast hole, spray means intermediate the upper and lower ends of said spout for spraying a second material into the path of gravitational movement of said granular material therethrough, means for operating said spray means in response to the flow of granular material through said spout to thereby obtain a uniform dispersion of said second material in said granular material, and means for regulating the rates of supply of both of said materials to thereby deliver a proportioned mixture thereof through said spout.

3. An apparatus as defined in claim 2 characterized by said last-named means comprising a valve damper movably supported in said spout and operating to define 61 a meter opening through which said granular material gravitates through said spout, and means for adjusting the position of said valve damper in said spout to vary the size of said meter opening and regulate the rate of flow of said granular material through said spout.

4. An apparatus as defined in claim 2 characterized by the provision of a downwardly inclined chute extending between said hopper and spout, and by said last-named means comprising means for adjusting the angular position of said chute relative to said hopper.

5. An apparatus for filling an explosive charge of granular material in a blast hole comprising a vertically extending spout, a hopper for supplying said granular material to said spout for gravitational movement therethrough, a traction vehicle on which said spout and hopper are mounted, means including said vehicle for centering the position of said spout over a blast hole, means for regulating the rate of flow of said granular material through said spout comprising a pair of valve dampers arranged in oppositely and downwardly inclined positions with their lower edges cooperating to define a meter opening through which said granular material gravi-tates through said spout, pivot supports at the upper edges of and mounting said dampers in said spout for movement in opposite rotational directions relative to each other, means for adjusting the positions of said dampers in said spout to vary the size of said meter opening and regulate the rate of flow of said granular material through said spout, spray means arranged below said meter opening and above the lower end of said spout for spraying a second material into the granular material flowing therethrough, means for operating said spray means in response to the flow of granular materials through said spout to thereby obtain a uniform dispersion of said second. material in said granular material, and means for regulating the rate at which said second material is sprayed into said spout to thereby deliver a proportioned mixture of said granular material and said second material through said spout.

6. An apparatus for filling an explosive charge of granular material in a blast hole comprising a vertically extending spout, a hopper for supplying said granular material to said spout for gravitational movement therethrough, a traction vehicle on which said spout and hopper are mounted, means including said vehicle for centering the position of said spout over a blast hole, means for regulating the rate of flow of said granular material through said spout comprising a pair of valve dampers arranged in oppositely and downwardly inclined positions with their lower edges cooperating to define a meter opening through which said granular material gravitates through said spout, pivot supports at the upper edges of and mounting said dampers in said spout for movement in opposite rotational directions relative to each other, means for adjusting the positions of said dampers in said spout to vary the size of said meter opening and regulate the rate of flow of said granular material through said spout, spray means arranged below said meter opening and above the lower end of said spout for spraying a second material into the granular material flowing therethrough, a spring biasing the movement of one of said valve dampers in a direction away from its adjusted position, said one valve damper being movable to its said adjusted position against the act-ion of said biasing spring in response to movement of granular material through said spout, means operated by movement of said one damper valve against the action of said biasing spring to its adjusted position for actuating said spray means to thereby obtain a uniform dispersion of said second material in said granular material, and means for regulating the rate at which said second material is sprayed into said spout to thereby deliver a proportioned mixture of said granular material and said second material through said spout.

(References on following page) References Cited in the file of this patent 2,782,962 UNITED STATES PATENTS 239031969 835,595 Bishop NOV. 13, 21906 2,097,914 Cooper et a1. Nov. 2, 1937 5 725 371 2,101,315 Kemp Dec. 7, 1937 2,745,346 Aitchison et 'al May 15, 195'6 8 Mercer Feb, 26, 1957 KoIbe Sept. 15, 1959 FOREIGN PATENTS Great Britain Mar. 2, 1 955 Great Britain Oct. 23 1 957