US3236147A

US3236147A - Apparatus for manufacturing blasting cartridges

Info

Publication number: US3236147A
Application number: US369228A
Authority: US
Inventors: John F Green
Original assignee: Cherry Burrell Corp
Current assignee: Cherry Burrell Corp
Priority date: 1964-05-21
Filing date: 1964-05-21
Publication date: 1966-02-22
Anticipated expiration: 1983-02-22

Description

J. F. GREEN Feb. 22, 1966 APPARATUS FOR MANUFACTURING BLASTING CARTRIDGES 2 Sheet s-Sheet 1 Filed May 21, 1964 Feb. 22, 1966 J. F. GREEN 3,236,147

APPARATUS FOR MANUFACTURING BLASTING CARTRIDGES Filed May 21, 1964 2 Sheets-Sheet 2 IN VENTOR. L2H A 6270 United States Patent 3,236,147 APPARATUS FOR MANUFACTURING BLASTING CARTRIDGES John F. Green, Montclair, Calif., assignor to Cherry- Burrell Corporation, Cedar Rapids, Iowa, a corporation of Delaware Filed May 21, 1964, Ser. No. 369,228 7 Claims. (Cl. 86--20) This invention relates to apparatus for manufacturing blasting cartridges and, more particularly, is concerned with apparatus which manufactures such cartridges from ammonium nitrate.

It has been found that ammonium nitrate can be used as an inexpensive but powerful explosive. It has been shown to have excellent cratering qualities and it is stable under normal environmental conditions, making it safe to handle. Because it is highly stable, ammonium nitrate is diflicult to detonate completely and effectively. Sensitizing agents are therefore employed to make the ammonium nitrate sensitive to Primacord or caps while not affecting its sensitivity to mechanical friction, mechanical impact, or high temperature.

Because ammonium nitrate is highly stable and can be readily transported in bulk form, it is desirable that cartridges be made up in the field. This permits the cartridges to be made to any desired size as required. For example, in underwater blasting techniques, it has been found that cartridges made with long, thin, flexible, plastic casings filled with sensitized ammonium nitrate and with a Primacord threaded through the center of the casing makes a very effective blasting cartridge. Such plastic casings may, for example, be two and a half to three inches in outside diameter by ten to fifteen feet in length.

The present invention is directed to apparatus for making up cartridges of sensitized ammonium nitrate to any desired size. Cartridges can be made up in the field using ammonium nitrate in bulk form, the apparatus adding the sensitizing fluid to the ammonium nitrate and inserting the Primacord through the cartridge automatically. The manufacturing apparatus of the present invention ensures that the ammonium nitrate and sensitizing fluid are thoroughly mixed in exactly the correct proportion. At the same time, the apparatus is rugged in construction yet it can be easily assembled and disassembled in the field and is safe and foolproof in its operation.

In brief, the apparatus of the present invention comprises a hopper for receiving the ammonium nitrate. A horizontal filling spout is associated with the hopper. A rotating auger extends through the bottom of the hopper and out to the end of the spout, the auger pushing the solid material out the end of the spout as it rotates. A spray nozzle is secured to the end of the auger adjacent the end of the spout. Sensitizing fluid is pumped through a passage extending through the auger and communicating with the spray nozzle so that as the auger rotates, the sensitizing fluid is sprayed out into the ammonium nitrate material as it is ejected from the end of the spout. A plastic casing is fitted tightly over the end of the spout and the sensitized ammonium nitrate mixture is packed into the casing. Means is provided for simultaneously feeding Primacord into the material. With both ends of the casing then securely bound, a complete watertight cartridge is formed-which is particularly adapted for use in underwater blasting.

For a more complete understanding of the invention, reference should be made to the accompanying drawings wherein:

FIGURE 1 is a side elevational view of the apparatus of the present invention;

FIGURE 2 is an end view of the apparatus; and

Patented Feb. 22, 1966 "ice FIGURE 3 is an enlarged sectional view taken substantially on the line 33 of FIGURE 2.

Referring to the drawings in detail, the numeral 10 indicates generally an angle iron frame which includes four vertical support legs 12, upper side rails 14 and lower side rails 16. These are joined by upper and lower end rails 18 and 20 to form an open box type frame.

Mounted on top of the frame is a hopper 22 which receives the ammonium nitrate in granular form. The lower end of the hopper 22 is joined to a feed chamber 24 through which passes a screw or auger feed assembly 26. The auger feed assembly includes a shaft 28 which is journalled by suitable bearings in a support housing 30 carried by the frame 10 behind the chamber 24. The rear end of the shaft 28 is provided with a sheave 32 by which the auger feed is driven.

Mounted on the front of the feed chamber 24 is an elongated spout 34. The screw feed 26 extends to the open end 36 of the spout.

An air motor 38 is mounted on the frame 10 and is adapted to be driven by compressed air from an air compressor (not shown). The air so applied to the motor is first passed through an air filter 40, an air regulator 42, and an air lubricator 44 to a motor start-stop valve 46. The air then passes through a valve 48 for regulating the flow to control the speed of the air motor 38.

The motor 38 drives a jack shaft 50 journalled in bearings supported by

support brackets

52 and 54 in front and by a bracket 56 in the rear. The support brackets are secured to the frame -10. The motor 38 is coupled to the jack shaft 50 through a belt 58 running on a sheave 60 on the shaft of the motor 38 and a sheave 62 on the jack shaft 50. The jack shaft 50 in turn is coupled to the shaft 28 through belts -65 driven from a sheave 66 on the jack shaft 50 and engaging the sheave 32 on the shaft 28.

As thus far described, the apparatus provides a means of feeding ammonium nitrate material from the hopper 22 out of the end 36 of the spout 34 by an anger or screw feed. In operation, a casing in the form of a sleeve tied off at one end and open at the other end is slipped over the spout 34 prior to the filling operation. The casing slides off the spout as the casing is filled by the auger feed.

In order to safely mix a sensitizing fluid with the ammonium nitrate, a positive pressure fluid pump 68, such as a gear pump, is mounted on the frame 10 and driven from the jack shaft 50 by means of a belt 78 engaging a sheave 72 on the inner end of the jack shaft .50. The belt engages a variable diameter sheave 74 on the shaft of the pump 68. The variable sheave 74 provides a means of adjusting the delivery rate of the pump in relation to the feed rate of the ammonium nitrate by the auger feed assembly 26. The intake side of the pump 68 is adapted to be connected to a source (not shown) of suitable sensitizing fluid. The discharge side of the pump 68 is connected through a flexible tubing 76 to a rotary fluid coupler 78 mounted on the back end of the shaft 28 of the auger feed assembly 26. The rotary coupler communicates with a passage extending through the shaft 28 along the axis of rotation thereof, the passage being indicated at 80.

Referring to FIGURE 3, the passage 80 extends to the end of the shaft 28 adjacent the opening 36 of the spout 34. A nozzle element indicated generally at 82 threadably engages the shaft 28 at the end and communicates with the internal passage 80. The nozzle element 82 includes a hub portion 84 having an internal chamber 86 connected by a short passage 88 to the passage 80 of the shaft 28. A ball check valve 90, loaded by a spring 92, permits flow of fluid under pressure from the passage 80 into the chamber 86 but prevents back flow of fluid into the passage 80.

The hub 92 is closed by a cap 94 having an opening 96 for emitting the sensitizing fluid. In addition, three hollow spray heads 98 project outwardly from the hub 92. Each of the spray heads has a series of springs 97 communicating with an internal passage 99 by means of which fluid is discharged by the nozzle element. The entire nOZZle together with the spray heads rotate with the shaft 28. Thus as the shaft 28 rotates, causing the auger feed to discharge ammonium nitrate out the end of the opening 36, the sensitizing fluid is discharged into the ammonium nitrate and thoroughly mixed by the rotary action of the spray heads 98. By this arrangement, a uniform mixture is obtained outside of the spout, so that the sensitized explosive does not come in contact with regions where mechanical parts having relative motions might come in contact, and act to detonate the explosive mixture.

At the same time, the sensitized mixture is fed into the casing, a Primacord fuse is embedded in the mixture in the casing. This is accomplished by means of a feed tube 100 which extends along the outside of the spout 34. The outer end of the feed tube extends beyond the nozzle unit 82 and is bent inwardly so that the opening at the outer end of the feed tube is near the center of the casing. Thus the Primacord fuse is imbedded in the sensitized ammonium nitrate within the casing. As the casing is filled with the sensitized mixture, it is continuously withdrawn from the feed tube 100. The Primacord may be threaded through the tube from a reel (not shown) that is rotatably supported on the frame 10.

When the casing is filled with the mixture, the casing is tied off at the open end and the prima fuse cord is cut to the desired length. In this way, a waterproof cartridge is formed to any desired length by the apparatus of the present invention.

In order to do underwater blasting, it may be desirable to add ballast to the cartridge to ensure that it remains submerged. This may be accomplished by providing the casing with an auxiliary tubular chamber so that the casing in cross-section is in the form of a figure eight. The auxiliary chamber of the casing is filled with sand or other suitable material for adding ballast weight to the finished cartridge.

Filling of the auxiliary chamber in the casing can be accomplished by means of a second hopper 102 having a canted bottom 104. An air diffuser 106 is provided on the bottom of the hopper to which is connected a supply of air through a suitable air line 108. The air diffusing into the canted bottom of the hopper blows the sand out of the tube 110 which, for convenience, passes through the hopper 22 and is bent downwardly as indicated at 112 to form an auxiliary spout 113 directly above the spout 34. The auxiliary spout 113 provides means for blowing sand into the auxiliary chamber of the casing to add ballast to the cartridge. 'From the above description, it will be recognized that apparatus has been provided for making blasting cartridges using ammonium nitrate and a sensitizing liquid. The apparatus provides for thorough mixing of the ammonium nitrate and the sensitizing material in accurately controlled proportions. It permits cartridges to be made up of any desired size. At the same time, the apparatus minimizes any danger of premature explosion of the sensitized material by providing mixing within the casing of the cartridge at a point remote from any source of heat, friction or other disturbing influences which might otherwise be a source of danger.

What is claimed is:

1. Apparatus for manufacturing ammonium nitrate blasting cartridges comprising a hopper for receiving the ammonium nitrate, a hollow spout adapted to receive a plastic casing over the end of the spout, a rotatable auger extending through the bottom of the hopper and out to the end of the spout for feeding ammonium nitrate from the hopper out the end of the spout into the casing, the

auger having a fluid passage extending through the entire length of the auger, a nozzle element including a plurality of radially extending spray heads secured to the end of the auger and projecting'beyond the end of the spout, the nozzle element being rotatable with the auger, a fluid pump adapted to be connected to a source of sensitizing fluid, means connecting the output of the pump to the fluid passage in the anger at the end remote from the nozzle element, means for simultaneously driving the pump and the auger to effect mixing of the sensitizing fluid with the ammonium nitrate as it is pushed out of the spout into the casing, and means including a tube extending along the outside of the spout for directing a fuse cord into the casing and immersing the cord in the ammonium nitrate in the casing, one end of the tube extending beyond the nozzle element and being bent inwardly to provide an opening positioned in front of the nozzle.

2. Apparatus for manufacturing ammonium nitrate blasting cartridges comprising a hopper for receiving the ammonium nitrate, a hollow spout adapted to receive a plastic casing over the end of the spout, a rotatable auger extending through the bottom of the hopper and out to the end of the spout for feeding ammonium nitrate from the hopper out the end of the spout into the casing, the auger having a fluid passage extending through the entire length of the auger, a nozzle element including a plurality of radially extending spray heads secured to the end of the auger and projecting beyond the end of the spout, each spray head having a passage communicating with the fluid passage in the auger and opening at the outer radial end of the spray head, the nozzle element being rotatable with the auger, a fluid pump adapted to be connected to a source of sensitizing fluid, means connecting the output of the pump to the fluid passage in the auger at the end remote from the nozzle element, means for simultaneously driving the pump and the auger to effect mixing of the sensitizing fluid with the ammonium nitrate as it is pushed out of the spout into the casing, and means including a tube extending along the outside of the spout for directing a fuse cord into the casing and immersing the cord in the ammonium nitrate in the casing.

3. Apparatus for manufacturing ammonium nitrate blasting cartridges comprising a hopper for receiving the ammonium nitrate, a hollow spout adapted to receive a plastic casing over the end of the spout, a rotatable auger extending through the bottom of the hopper and out to the end of the spout for feeding ammonium nitrate from the hopper out the end of the spout into the casing, the auger having a fluid passage extending through the entire length of the auger, a nozzle element including a plurality of radially extending spray heads secured to the end of the auger and projecting beyond the end of the spout, each spray head having a passage communicating with the fluid passage in the auger and opening at the outer radial end of the spray head, the nozzle element being rotatable with the auger, a fluid pump adapted to be connected to a source of sensitizing fluid, means connecting the output of the pump to the fluid passage in the auger at the end remote from the nozzle element, and means for simultaneously driving the pump and the auger to effect mixing of the sensitizing fluid with the ammonium nitrate as it is pushed out of the spout into the casing.

'4. Apparatus for manufacturing ammonium nitrate blasting cartridges comprising a hopper for receiving the ammonium nitrate, a hollow spout adapted to receive a plastic casing over the end of the spout, a rotatable auger extending through the bottom of the hopper and out to the end of the spout for feeding ammonium nitrate from the hopper out the end of the spout into the casing, a nozzle element including a plurality of radially extending spray heads secured to the end of the auger and projecting beyond the end of the spout, the nozzle element being rotatable with the auger, a fluid pump adapted to be connected to a source of sensitizing fluid, means connecting the output of the pump to the nozzle element, means for simultaneously driving the pump and the auger to effect mixing of the sensitizing fluid with the ammonium nitrate as it is pushed out of the spout into the casing, and means including a tube extending along the outside of the spout for directing a fuse cord into the casing and immersing the cord in the ammonium nitrate in the easing, one end of the tube extending beyond the nozzle element and being bent to provide an opening positioned in front of the nozzle along the axis of rotation of the auger.

5. Apparatus for manufacturing ammonium nitrate blasting cartridges comprising a hopper for receiving the ammonium nitrate, a hollow spout adapted to receive a plastic casing over the end of the spout, a rotatable auger extending through the bottom of the hopper and out to the end of the spout for feeding ammonium nitrate from the hopper out the end of the spout into the casing, a nozzle element including a plurality of radially extending spray heads secured to the end of the auger and projecting beyond the end of the spout, each spray head having a passage communicating with the fluid passage in the auger and opening at the outer radial end of the spray head, the nozzle element being rotatable with the auger, a fluid pump adapted to be connected to a source of sensitizing fluid, means connecting the output of the pump to the nozzle element, and means for simultaneously driving the pump and the auger to efiect mixing of the sensitizing fluid with the ammonium nitrate as it is pushed out of the spout into the casing.

6. Apparatus for making blasting cartridges using an explosive particulate solid material and a sensitizing liquid material comprising a spout, means for pushing the solid material out the end of the spout, means including a hollow shaft extending through the spout and projecting beyond the end of the spout, a nozzle element secured to the end of the shaft projecting beyond the end of the spout, the nozzle element including a plurality of radially projecting spray heads, each head having a radial passage opening at the outer projecting end of the spray head, the radial passages communicating with the interior of the hollow shaft for mixing the liquid in the solid material as it leaves the spout, a check valve positioned between the radial passages in the spray head and the interior of the hollow shaft, and means for guiding a fuse cord into the mixture beyond the position of the nozzle element.

7. Apparatus for making blasting cartridges using an explosive particulate solid material and a sensitizing liquid material comprising a spout, means for pushing the solid material out the end of the spout, and means including a hollow shaft extending through the spout and projecting beyond the end of the spout, a nozzle element secured to the end of the shaft projecting beyond the end of the spout, the nozzle element including a plurality of radially projecting spray heads, each head having a radial passage opening at the outer projecting end of the spray head, the radial passages communicating with the interior of the hollow shaft, for mixing the liquid in the solid material as it leaves the spout.

References (Iited by the Examiner UNITED STATES PATENTS 542,322 7/ 1895 Batchelor 8631 1,142,841 6/1915 Raleigh 25925 1,459,657 6/1923 Dempsey 259168 1,855,548 4/1932 Forster 25910 2,363,569 11/1944 Caldwell et al. 8631 X 3,005,373 10/1961 Ransom 8620 3,127,835 4/1964 Alexander 8620 3,158,358 11/1964 Fischer 259-44 X FOREIGN PATENTS 1,105,552 7/1955 France.

BENJAMIN A. BORCHELT, Primary Examiner.

Claims

7. APPARATUS FOR MAKING BLASTING CARTRIDGE USING AN EXPLOSIVE PARTICULATE SOLID MATERIAL AND A SENSITIZING LIQUID MATERIAL COMPRISING A SPOUT, MEANS FOR PUSHING THE SOLID MATERIAL OUT THE END OF THE SPOUT, AND MEANS INCLUDING A HOLLOW SHAFT EXTENDING THROUGH THE SPOUT AND PROJECTING BEYOND THE END OF THE SPOUT, A NOZZLE ELEMENT SECURED TO THE END OF THE SHAFT PROJECTING BEYOND THE END OF THE SPOUT, THE NOZZLE ELEMENT INCLUDING A PLURALITY OF RADIALLY PROJECTING SPRAY HEADS, EACH HEAD HAVING A RADIAL PASSAGE OPENING AT THE OUTER PROJECTING END OF THE SPRAY HEAD, THE RADIAL PASSAGES COMMUNICATING WITH THE INTERIOR OF THE HOLLOW SHAFT, FOR MIXING THE LIQUID IN THE SOLID MATERIAL AS IT LEAVES THE SPOUT.