US3070012A - Blasting devices - Google Patents

Description

Dec. 25, 1962 E. c. FlLsTRuP 3,0700l2v BLASTING DEVICES Filed may 19, 1959 2 sheets-sheet 1 TTOPNEYS IN V EN TOR EDWARD c. FlLsTRuP Dec. 25, 1962 C F'LSTRUP 3,0790! BLASTING DEVICES Filed May 19, 1959 2 Sheets-Sheet 2 FIG@ 2|) 67\ 6a) es) 65) 62E 6k Q INVEN TOR. EDWARD c. FlLsTRUP BY M, 2f

States lice 3,070,012 BLASTING DEVICES Edward C. Filstrup, St. lIoseph, Mich., assignor to Olin Mathieson Chemical Corporation, East Alton, Ill., a corporation of Virginia Filed May 19, 1959, Ser. No. 814,252 2 Claims. (Cl. 102-25) This invention relates to blasting devices and more particularly to material breaking cartridges utilizing Ia gas under pressure as the work performing medium.

Material breaking cartridges using compressed gas to execute the required work are well known and Widely used in the mining industry. Such cartridges or blasting devices are all reliant upon the sudden release of compressed gas to give a quasi explosive effect. The predecessors of this type of blasting cartridges consisted essentially of a cylindrical gas containing cartridge having Venting means. The cartridges were charged with gas under considerable pressure, sealed and then conveyed to the face to be worked. The compressed gas within these cartridges was released by elaborate remote control means. More recently, the practice has been to place an uncharged cartridge in the bore hole and pump gas through a suitable conduit into the cartridge in situ. Conventionally, these cartridges are formed of high strength materials and are provided with a relatively weak member which lshears or ruptures so as to liberate the gas from the cartridge body. Since the amount of pressure that can be built up in the cartridge body is dependent upon the strength of the expendable member, the quantity of energy developed by the liberation of the gas can be controlled within relatively close limits. Such cartridges are generally satisfactory but have one serious inherent drawback. After each shot, the discharge end of the cartridge must be dismantled to remove the expandable portion which has ruptured or sheared and to replace it with a new one.

This shortcoming has been well recognized and has led to a concerted eifor-t for the development of automatic shells. While many so-called automatic shells have been presented, they have met with only a modicum of success. The previous types of automatic cartridges are operable, but they are very heavy, complex and unreliable. Although the expendable portions of the shell have been eliminated, this elimination has introduced new and more serious problems. Normally, the known automatic shells rely upon a series of two or more control or pilot valves -to initiate the main release valve. Such complexity of design leads to cartridges that are ditlicult to control and exceedingly difficult to discharge at a desired predetermined pressure. In addition, the great number of moving parts in the automatic shells prior to the advent of the present invention has confronted the industry with a formidable sealing problem.

Therefore, it is an object of this invention to provide new and improved automatic or semi-automatic material breaking devices utilizing compressed gas. A further object is to provide a device of this character having novel gas release means. Another object of this invention is to provide a simplified automatic or semieautomatic shell overcoming the disadvantages of the prior art.

The manner in which these and other objects are achieved will be apparent from the following specication together with the drawing in which:

FIGURE 1 is a longitudinal sectional view of a device illustrating a preferred embodiment of the present invention;

. FIGURE 2 is a fragmentary longituidnal sectional view of the venting means illustrated in FIGURE 1 showing the position of the venting mechanism immediately prior to discharge of the cartridge;

FIGURE 3 is a fragmentary longitudinal sectional view similar to FIGURE 2 but showing the position of the venting mechanism during discharge of the cartridge;

FIGURE 4 is la cross sectional view along the line IV-IV of FIGURE 2;

FIGURE 5 is a fragmentary longitudinal sectional view of the cartridge illustrated in FIGURE l but showing another form of venting mechanism;

FIGURE 6 is a fragmentary longitudinal sectional view of a cartridge of the type shown in FIGURE 1 but illustrating another embodiment of the present invention; and

FIGURE 7 is a longitudinal sectional view of another embodiment of the present invention.

The same numbers are used throughout the drawing to identify similar members.

Referring to FIGURE 1 which illustrates a preferred embodiment of the invention, an elongated tubular body formed of metal of a strength to contain gas under high pressures, for example, pressures from 6,000 to 20,000 pounds per square inch, is indicated generally at 1. Only a portion of this tubular body, which may be of the order of 50 inches in length, is shown. The outer diameter of the body is such that that it may set freely within a bore drilled in the face of the material, such as coal, to be mined and broken down. One end of the tubular body is provided with a neck portion of slightly reduced diameter which is screw threadedly attached to the head 2 as shown at 3. The seal between the tubular body and the head is completed by an annular resilient sealing means 4 contained in groove 5 and a metallic sealing ring 6 terminating in an area 7 of reduced o cross section in contact with the main dump valve 8.

The end of the cartridge is closed by end cap 9 suitably attached to head 2. Main valve S is slidable `within head 2 and the juncture between these two members is rendered leak-proof by means of O-ring 10 or other resilient sealing means located in annular groove 11 of the head. The end cap 9 contains a rigid cylindrical member 12 which is screw threadedly attached to the head as indicated at 13. The seal between this rigid cylindrical member and the head is completed -by O-ring 14 in annular groove 15. The rigid cylindrical member 12 is provided with an anular protuberance 16 on its forward face to provide a positioning means for the helical valve return spring 17. A poppet valve seat member 18 having valve orifice 19 passing therethrough is slidably positioned in a central cavity 20 of the rigid cylin- `drical member 12. The narrowed forward portion 21 of the valve seat member, in like manner, is slidably positioned in passageway 22 of the rigid cylindrical member. If desired, the position of valve seat 18 may be maintained in part by one or more positioning iingers 23 held by rigid cylindrical member 12. The valve seat is normally urged to a forward position by helical spring 24, the tension of which may be adjusted by the pressure adjustment nut 25 having orifice 26 passing therethrough. 'Ihe end cap 9 is provided with a vent 27 cornmunicating with the exterior of the cartridge. The end cap and cylindrical member can vbe secured by bolts 74 or by :any other suitable means. The stem or reduced area portion I2,1 of the valve seat member 18 is in gastight relationship to the rigid cylindrical member 12 by means of suitable lannular resilient packing 28 in annular groove 29. A valve closure member indicated generally at 30, cooperates with the valve seat 18 in passageway 22. The tapered valve surface 31 of the valve closure member is urged against the forward surface 32 of the valve seat member to form a tight seal.

A Belleville spring 33 or other suitable means is positioned about the shank of the valve closure member 3l) between the'head 34 thereof and the shoulder 35 of the rigid cylindrical member 12. Excessive motion of the valve closure member is restricted by stop pins 36.

As more clearly shown in FIGURE 4, the head of the kpoppet valve is provided with one or more slots 37 which continue throughout the length of the poppet valve closure mernlber to the tapered valve surface 31.

Reset latch 38 is pivotally mounted at 39. The latch is provided with tooth 40 which cooperates with shoulder 41. The opposite end 42 of the reset latch is urged upwardly by spring 43. Reset pin 44 passing through endrcap 9 is provided. The main dump valve 8 is provided with one or more air passagesways 45 serving as a means of communication between themain chamber 46 and secondary chamber 47. The effective cross sectional areas of the passageways 45 are smaller than the effective cross sectional area of passageways 19 and 26 and vent 27.

-In operation, compressed air or other suitable gas is introduced into main chamber 46 by conventional means not shown. The air passes through passageway 45 into the secondary chamber 47. Thus, the pressure on either side of main valve 8 is substantially equalized. However, because of the greater effective cross-sectional area of valve 8 in the secondary chamber than in the main chamber, the valve is urged into sealing relationship with metallic sealing ring 6 and maintains discharge ports 48 in a closed position. As the pressure increases in secondary chamber 47, it moves poppet valve closure member 30 and valve seat member 18 in opposition to Belleville 'spring 33 and helical spring 24, respectively.

As shown in yFIGURE 2, this movement continues until -the Belleville spring 33 is fully compressed between head 34 of the poppet valve closure member and shoulder 35 of .the rigid cylindrical member 12. Poppet valve seat member 18 slides back under this pressure until spring 43 on the reset latch 38 forces tooth 40 thereof into engaging relationship with shoulder 41 of the valve seat. Compressed gas passing through slots 37 of the valve closure member 30 exerts a pressure on the forward surface of the valve seat member 32. This causes further movement of valve seat 18 against spring V24 and a slight separation between the tapered valve surface 31 of the valve closure member 3i) and the forward surface of the valve seat member 32. Thus, a portion of the gas in secondary chamber 47 is exhausted through slots 37, valve orifice 19, orice 26 and vent 27. When the pressure in secondary chamber 47 is reduced, Belleville spring Y33 snaps back into a relaxed conditoin. This completely -opens valve orifice 19, as shown in VFIGURE, 3, permitting the ygas to escape therethrough at a greater rate than it enters passageway 45 through main valve 8. This suddent imbalance of pressures on either side of the main valve 8 forces it into action against spring 17 and away from discharge ports 48. The charge of compressed gas in main chamber 46 is thus completely and instantaneously .released to the surrounding work face which is to be broken down. When the charge of air leaves main chamber 46 reducing thepressure therein, main valve 8 is returned to its original position by helical spring 17.

After the shot has been made, the cartridge is returned to firing condition by merely depressing reset pin 44 against the end 42 of reset latch 38 and spring 43. The reset latch 38 then pivots about point 39, thus disengageing tooth 40 from shoulder 41 of the valve seat member 18 which is Ithen `returned to its original position by the action of spring 24. The cartridge of this embodiment is rendered completely automatic by elimination of reset latch 38. When the reset latch is not present in the cartridge, valve sea-t member 18 is returned to its original position by :spring 24 upon removal of the compressed gas from chamber 47 and the cartridge is in condition to receive another charge of compressed gas.

Valve seat 1S and the closure member 3i) cooperate to open practically instantaneously at a predetermined pressure -to insure the sudden release of the gas charge from the main chamber. The pressure at which this valve opens can be readily controlled by the tension applied to spring 24 through the pressure adjustment nut 25. Another factor serving as a release pressure control is the relationship of Ithe areas of head 34 of the poppet valve closure member and forward surface of the valve seat member 32. As the ratio be-tween these two areas increases, the pressure required to open the valve increases. Likewise, the strength of the Belleville spring 33 about head 34 of the valve closure member 3) can be varied.

In the embodiment shown in FIGURE 5, a slightly different type of lrelease valve arrangement is employed. The valve seat member 18 is yieldably mounted within the cylindrical rigid body 12 and is normally held in place against shoulder 49 thereof by spring 24'. The narrowed portion 21 of the valve seat member is slidably sealed within the central aperture 50 of valve retaining means 51 by means of suitable resilient sealing means 52. The poppet valve closure member 30 cooperates with narrowed portion 21 of the valve seat member to close valve orifice 19. The seal between the poppet valve closure member 30 and the valve retaining means 51 can be a metal-to-metal seal or a resilient sealing means 53 can be utilized as shown. The valve closure member is maintained in operable position by any suitable keeper means indicated at 54. The joint lbetween the valve retaining means 51 and the rigid cylindrical body 12 is maintained gas-tight 'by means of O-rings 55 or other suitable resilient sealing means. Also, valve retaining means 51 is provided with one or more ports 56 therethrough.

In the ,operation of this embodiment, the pressure on both sides of the valve retaining means 51 is maintained substantially equal because of ports 56 therethrough. However, the force on the side of the valve retaining means facing the secondary chamber 47 is greater than on the other side because of the differential area. This force causes the valve vassembly to move in a direction away from the secondary chamber until the poppet valveY closure member 30 is forced away from valve retaining means 51 by the narrowed portion 21 of the valve seat member 18. This movement breaks the seal between the valve closure member 30 and valve retaining means 51 and permits the gas to escape through valve orifice 19. In accordance with this embodiment, the effective cross sectional area of the air passageway 45 through main valve 8 must be less than the effective area of the ports 56 through cylindrical valve retaining means 51. This results in the sudden reduction of pressure in the sec,- ondary chamber 47 and the substantially instantaneous dumping of the gas charge from main Chamber 46 in the same manner as described above.

In the embodiment shown in FIGURE 6, the shell is provided with an end cap 57 having one or more vents 58 passing through the base thereof. The end cap is also provided with set screw 59 and back-up plug 60. A cylindrical extension 6-1 of end cap 57 is screw threadedly attached to head 2. The seal between these two members is completed by means of O-ring 62 or other suitable resilient sealing or gasket-means. A valve retaining means 63 is siidably sealed within the cylindrical extension 61 by means of O-ring 64. A helical spring 65 is positioned between the end of cylindrical extension 61 and shoulder 66 of valve retaining means 63. However, excessive movement of valve retaining means 63 is restricted by `annular shoulder 67 within head `2. Valve retaining means 63 is provided with a centrally located passageway 68 passing therethrough and also with one or more ports 69 passing through shoulder 66.V

Valve member 70 rests on the surface of valve retaining means 63 and the stem 71 of this valvemember passes through passageway 68 in alignment with set screw 59. The seal between the valve member 70 and the valve retaining means 63 can be metal-'tolmetal or a resilient Sealing means 72 as shown can be employed. Valve member 70 is provided with suitable keeping means 73.

In operation, as the pressure in secondary chamber 47 increases, valve retaining means 63 and valve member 70 are pressed tightly together and are urged as a unit against helical spring 65. Although the pressure on both sides of shoulder 66 of the valve retaining means 63 is substantially equal because of ports 69, this member is urged away from the secondary chamber because of the diiferential effective areas involved. This movement continues until such time as stem 71 of valve member 70 contacts set screw 59. At this point, the valve member 70 can move no further and conditions remain static until such time as the pressure in secondary cham-ber 47 becomes suiciently great to overcome the force of spring 65. At this instant, the effective area of the valve retaining means 63 exposed to the pressure in chamber 47 suddenly becomes very much greater than the area of shoulder 66 in contact with spring 65, and as a result valve retaining means 63 moves exceedingly rapidly toward the end cap 57. As this happens, the seal between valve retaining means 63 and the valve member 70 is broken because the movement of valve member 70 is restrained by set screw 59 whereas the movement of the valve retaining means 63 is relatively unrestrained. In this manner, the gas pressure in secondary chamber 47 is very rapidly relieved through passageway 68 and vents 58. This sudden reduction in pressure eiects the operation of the main sleeve valve in the same fashion as described in the first embodiment.

Referring now to the embodiment shown in FIGURE 7, the shell is provided with an end cap 9 which is screw threadedly attached to member 75 which, in turn, is attached to head 2 as shown. A rigid cylindrical member 12 carries within its central perforation valve seat 18 provided with valve orifice 19, poppet valve closure member 30, helical spring 24, and pressure adjustment nut 25. Valve seat member 18 is retained in position by disc 76 while the seal between member 75 and cylindrical member 12 and between valve seat member 18 and member 75 are maintained by resilient O-rings 77 `and 78, respectively. Cylindrical member 12 is provided with a series of radial ports 79 which are in communication with vents 27. One or more vents may be employed but in any event their effective cross sectional area must be sufficiently great to permit a rapid reduction of pressure in secondary chamber 47.

In operation, the cartridge is filled as described in connection with the preceding embodiments and the gas pressure in secondary chamber 47 acts on valve closure member 30 in opposition to helical spring 24. At a predetermined pressure which can be controlled by the strength of spring 24 and the setting of adjustment nut 25, the valve closure member 30 is unseated from valve seat member 18 causing the valve closure member to move against spring 24. This movement results in opening radial ports 79 and the gas in secondary chamber 47 is then rapidly exhausted through valve orific 19, radial ports 79 and vents 27. This rapid reduction in the secondary chamber pressure permits the main sleeve valve to open abruptly and to instantaneously dump the gas charge from the main chamber in the same manner as in the preceding embodiments. After the gas is discharged from the shell, the poppet valve is returned to a closed condition by spring 24 and the main sleeve valve is returned to its position, closing the ports by helical spring 17. The cartridge is then in condition to be recharged.

The embodiments shown in FIGURES 5, 6 and 7 are completely automatic and in each instance the control valve is closed after discharging the shell by spring 24. However, it will be readily appreciated that the cartridges 55 of these embodiments 'can be rendered semi-automatic by the provision of any lsuitable reset latch mechanism including reset latches of the typ shown in connection with the rst embodiment. v 4

While four specific embodiments of the present invention has been shown, various modications will suggest themselves to those skilled in the art. Thus, various types of control valves and main release valves can be employed withinpthe sc ope of this invention. Likewise, the helical and Belleville springs shown, as well as the resilient O-rings, can readily be replaced by other suitable means. While the present discloseure is directed to blasting devices, it will be appreciated that the inve-ntion is applicable to any other type of apparatus in which a suddent release of gas under pressure is required.

What is claimed is:

1. A blasting device comprising a substantially cylindrical body closed at one end by an end cap provided with a vent, a main chamber for containing a charge of gas under pressure, a single control chamber between the main chamber and the end cap, lateral gas discharge outlets intermediate the ends of the body and passing through that portion of the body containing the main chamber, a gas pressure responsive main valve slidable within the cylindrical body between and separating the main chamber and control chamber and normally positioned to span and seal said outlets, a perforation through the main valve between the chambers and having a lesser eiective cross-sectional area than said vent, the end of the control chamber adjacent the end cap terminating in a rigidly mounted member provided with a passageway therethrough, the passageway being enlarged at each end to dene a shoulder at each end of the rigidly mounted member, a valve seat having a passageway therethrough, a portion of said valve seat movably mounted and sealed within the end of the passageway of the rigidly mounted member adjacent the end cap, and enlarged head portion on the valve seat abutting the shoulder at that end of the rigidly mounted member and limiting the movement of the valve seat, a valve having a tapered end portion loosely mounted in the other end of the passageway of the rigidly mounted member with the tapered end portion normally engaged with the passageway of the valve seat to seal the same, said valve having an enlarged head portion, a spring disposed between the head portion of the valve and the other shoulder of the rigidly mounted member, a second spring disposed between the head portion of the valve seat and the end cap to urge the valve seat toward the valve, air pressure in the control chamber causing said valve and valve seat to move against the force' of said springs until further movement of the valve is prevented by an adjacent shoulder of the rigidly mounted member acting through said spring, a further increase in air pressure causing said valve seat to move away from the valve to open the passageway in the valve seat and to vent the secondary chamber to the atmosphere.

2. The device of claim 1 in which latch means is pivotally mounted on the cylindrical body to engage the head portion of the valve seat after it has been moved a predetermined amount toward the end cap, and release means is further provided to disengage the latch from said valve seat.

References Cited in the file of this patent UNITED STATES PATENTS 2,122,706 Armstrong July 5, 1938 2,720,167 Hesson Oct. 11, 1955 2,720,168 Hesson Oct. 1l, 1955 2,720,169 Smith Oct, 11, 1955 2,771,032 Callahan Nov. 20, 1956 2,906,289 -Fox Sept. 29. 1959 FOREIGN PATENTS 199,541 Great Britain June 28, 1923 597,161 Germany May 18, 1934

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