US2120034A

US2120034A - Indestructible release mechanism for blasting cartridges

Info

Publication number: US2120034A
Application number: US71744A
Authority: US
Inventors: Leonard D Myers
Original assignee: SAFETY MINING CO
Current assignee: SAFETY MINING Co
Priority date: 1936-03-30
Filing date: 1936-03-30
Publication date: 1938-06-07
Anticipated expiration: 1955-06-07

Description

June 7,' 193s.

l. D. MYERS Fim March so, 193s s sheets-sheet 1 E `\h..w

L. D. MYERS June 7, 1938.

INDESTRUCTIBLE RELEASE MECHANISM FOR BLASTING CARTRIDGES Filed Harch 30, 1936 3 lSheets-Sheet; 2

@ sf a L. D. MYERS June 7, 1938.

INDESTRUCTIBLE RELEASE MECHANISM FOR BLASTING CARTRIDGES Filed March so, 193s 3 Sheets-Sheet 3 Patented June 7, 1938 11N-Iran sra'ras maar HNDESTRUCTIBLE RELEASE MECHANISM FDR BLASTING CARTRIDGES I corporation Application March 30, 1936, Serial No. 71,744

31 Claims.

This invention relates to new and useful improvements in indestructible release mechanism for blasting cartridges.

`Several different kinds of blasting substances have been developed in the past for use in place of ordinary explosives for breaking down materials, such as coal. These substances are intended to be confined in indestructible cartridges or shells primarily for convenience in handling, uniformity in blasting effect which is due to charging the cartridges at a central station under expert supervision and controlling the direction of application of the blasting forces, etc. cartridges or shells then Aare conveyed to the desired points oi' use and placed in drill holes formed in the material to be broken down. Representative examples of some of these diierent kinds of.

blasting substances or charges are as follows:

Carbon dioxide placed in the cartridge in liquid form and converted to the gaseous stage by the application of intense heat, V

Combinations of solids and liquids; such as quick lime and water, which are maintained separated until the blasting operation is to be performed whereupon the elements are permitted to mix to form a gas,

Liquids which are capable of being quickly vaporized by the application of heat,

Gaseous charges which will increase in volume rapidly when subjected to intense heat, and

Purely chemical mixtures; for example, decomposable salts, which when heated will liberate a non-iniiammable gas.

With all the aforementioned types of blasting substances or charges, a very rapid change of pressure occurs at the time of ring a cartridge charged with the same. Furthermore, the final pressure at which these charges are liberated is in most instances many times the pressure at which the charges are placed within the cartridges or shells. With some of these charges, the pressure at which the `same is placed in a cartridge is comparatively high and will be raised above the initial charging pressure by a rise in the temperature of the surrounding atmosphere'.

It will be appreciated that the confining oi' thes charges in cartridges until the desired blasting pressure is obtained presents a diflicult problem. i

Carbon dioxide has been the only one of the aforementioned types of blasting charges or substances which, as far as applicant is aware, has gone into extensive commercial use. The problem of successfully conning a charge of liquid carbon dioxide in an indestructible cartridge or The charged shell is probably more difficult than with any of the other examples mentioned. This is due to the fact that the charge is placed within the lcartridge at approximately a pressure of 1000 lbs. per square inch. The pressure of such a carbon dioxide charge will rise as high as 4000 lbs. perv .square inch when submitted to temperatures which are common in some localities during the summer months. When a carbon dioxide charge is heated for the purpose of converting it from a liquid to a gaseous stage, by the application of intense heat, the change takes place instantaneously. The pressures at which carbon dioxide charges have been released, in the commercial use of this type of blasting medium. have varied .from 12,000 lbs. to 30,000 lbs., more or less, per square inch. It will not be difficult to understand, that to be able to maintain this type -of blasting medium conned until a desired, predetermined blasting pressure is reached, and then suddenly liberate the charge cannot be accomplished with ordinary apparatus for controlling the flow of fluids at low pressures.

The method which has been most extensively adopted for effecting the desired control, inthe commercial'use of carbon dioxide as a blasting medium, consists of providing the indestructible cartridges or shells with rupturable wall portions.: Specifically, the rupturable wall portion takes the form of a disk which is associated with a discharge cap in such a manner that the central p01.- tion will be sheared from the remainder of the disk when a predetermined blasting pressure is obtained.

The only disadvantage which results from the use of a rupturable disk form of discharge control is that a new disk must be used with each new charge and the application of a new disk to a cartridge necessitates disassembly of the aforesaid discharge cap to permit the insertion of the new disk and then reassembly of the discharge cap to retain the disk in place. The development of an indestructible mechanism which would permit of accurate control of the discharge pressure of blasting substances or charges of the above referred to characters, and particularly carbon dioxide would eliminate the cost of providing a. new disk for each charge placed within a cartridge and would, of course, dispense with the necessity of disturbing the cartridge assembly to effect the substitution of a new disk.

It will be appreciated that with all of the types of blasting substances or charges above referred to, the interior of the chamber or chambers pruvided in the cartridges or shells for receiving the blasting medium is not available for use as a housing means forthe release mechanism.

This is due to the fact that where a heater is 'which will permitv it tobe located entirely exteriorly of theportion of the cartridge intended for use to confine the blasting medium.

It is the primary object of this invention to provide indestructible discharge mechanism for blasting cartridges, intended to receive any of the types of blasting charges above referred to, which Will eiectively and economically accomplish the desired control of the blasting charge so 'that blasting operations may be accomplished at any desired blasting pressures and with said pressures under accurate control.

.A further important object of the invention is to provide a form of indestructible discharge mechanism for blasting cartridges which will not occupy any portion of the chambers of the cartridges which are normally used for confining the blasting charges and their actuating devices. A still further important object of the invention is to provide discharge mechanism for blasting cartridges which will not necessitate any portion of the mechanism being replaced or adjusted after each ring operation.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a Dart of this specification and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a longitudinal sectional v iew of a fragmentary portion of a discharge cartridge with one form of indestructible discharge mechanism embodying this invention properly applied thereto,

Figure 2 is a transverse sectional view taken' on line 2-2 of Figure 1, l

Figure 3 is a transverse sectional view taken on line 3-3 of Figure 1,

Figure 4 is a longitudinalfsectional View of a fragmentary portionof a blasting cartridge with a modified form of indestructible release mechanism operatively associated therewith.

Figure 5 is a similar view to Figure 4 but discloses the discharge mechanism in two diierent l positions of operation,

Figure 6 is a transverse sectional view taken on line 6-6 of Figure 4,

Figure 7 is a 'longitudinal sectional View of a fragmentary portion of ablasting cartridge with a further modiiied form -of indestructible release mechanism embodying this invention operatively applied thereto, and

Figure 8 is a transverse sectional view taken on line 8-8 of Figure '7.

In the drawings, wherein for the purpose oi' at a location intermediate its ends.

formation so as to provide a chamber 2I.

complete disclosure of a cartridge of this character which is charged with carbon dioxide in liquid form, that is, gaslfied by the application of intense heat to produce the desired blasting energy, reference is hereby made to the patent issued to Dent Ferrell, et al., No. 1,805,541, issued May 19, 1931. n

Referring speciiically to the form of the invention illustrated in detail in Figures 1 to 3 inclusive, the discharge opening II of the cartridge I has threadedly connected thereto a tubular coupling member I2 which is provided with a plurality of obliquely arranged discharge ports I3 Inwardly of the series of ports I3, the coupling member I2 is provided with a shoulder I4 which functions as a valve seat. On the opposite side of the ports I3, to the shoulder I4, the coupling is provided with a partition I which, as will be described at a later point, acts as a guide for a compound valve member and also as a seat for a valve portion of said member. Outwardly of thecombined guide and seat forming partition I5, the coupling meinber I2 is bored out and internally screw-threaded` at I6 for being threadedly connected to the reduced end I1 of a casing member I3. This casing member I8 is provided with a valve guide I9 which has formed therein a circular series of apertures 2li. The casing member I8 is of tubular 'I'his chamberv2I is divided to a certain extent into two parts by the guide or partition I9 but these two parts are in constant communication with each other through the series of apertures 20. The outer end portion 22 of the casing member I8 is internally screw-threaded for receiving a plug 22 which functions to close the outer end ofthe chamber 20.

A packing ring or gasket 24 is provided to seal between the cartridge I0 and the coupling I2 to prevent leakage through this threaded connection. The joint between the coupling I2 and the casing member I8 is packed or sealed by a cup Packing rings or gaskets 21 and 23 are provided,

for sealing the joint between the closure plug 23 and the outer end of the casing member I8.

A compound valve device is provided and is designated -in its entirety by the reference character 29. One end of this compound valve device is enlarged to form a valve head 30/adapted to engage the shoulder orl seat I4. When this valve head 30 is seated on the shoulder I4, it functions to retain the blasting charge within the cartridge I il. The enlarged valve head-30 tapers rearwardly to blend into the stem portion 3|. As shown in Figures 1 and 3, the rearwardly tapering portion of the valve head 30 and the adjacent portion onfthe stem 3I are provided with a series of longivtudinally extending grooves 32. It will be noted by inspecting Figure 1 that when the Valve head 3Il is arranged in engagement with the valve seat* 65 cup leather 25 to form a valve device for closing ofi communication between the chamber 2I and the bore of the coupling I2 'which communicatesv with the discharge ports I3. When the valve head 30 is moved away from the valve seat I4, or into its dotted line position of Figure 1, the

series of longitudinally extending grooves 32 establish communication between the inner part of the chamber 2| and the bore of the coupling I2 which directly communicates with the discharge ports I3. It will be appreciated, therefore, that when the valve head 3U is unseated, the stem portion 3| of the compound valve device 29 will have been moved to a position where the grooves 32 will permit discharge of the contents oi the chamber 2| through the discharge ports I3 along with the contents of the cartridge I0.

For the purpose of charging the chamber 2| with a uid, such as air, under pressure, the closure plug 23 has formed therein a threaded aperture 33 which may be connected to auconduit leading from a suitable source of supply. To prevent discharge ofthe compressed fluid through the opening 33, a spring loaded check valve is provided for closing this opening. The ball check valve is retained in place by a cage 35 which is secured to the inner face of the closure plug 23' by means of the feet 36. These feet are intended to be suitably welded, or otherwise secured to the plug 23. For the purpose of initially closing both valve portions of the compound valve device 29, a spring 31 is provided, One end of this spring is received within a pocket 38 formed in the outer end of the valve device 29. The remaining end of the spring is connected to the closure plug 23 by means of the feet 36 of the valve cage 35.

The operation of this device may be described as follows:

It will be noted that there is provided a unitary, self-contained mechanism which may be detachably connected to the discharge end of a blasting cartridge I6. With this unitary device properly connected to the cartridge, compressed air, or the like, is to be charged into the chamber 2|. The pressure of this charge of air is to be such that it will retain the valve head 30 seated on the shoulder \I4 against. the pressure of the blasting charge within the cartridge Ill until the pressure of this blasting. charge reaches the desired working pressure at which time the blasting charge is intended to overcome the pressure within the chamber 2|. The charge of compressed air within the chamber 2| acts against the outer end of the valve stem 3| to maintain both valve portions of the device 29 seated or closed until the desired blasting pressure is attained within the cartridge.

After the chamber 2| is properly charged with compressedair, the cartridge Il) may be charged with the blasting medium. As stated above, this blasting medium may be of the form disclosed in the aforementioned Ferrell patent. The cartridge with its indestructible release mechanism is then ready to be transported to the location of a blasting operation and may be placed in a drill hole in the mine wall to be broken down. As is explained in the aforesaid Ferrell patent, the liquid carbon dioxide charge in the cartridge I is rapidly converted to a gas by means of a chemical heater unit which is electrically energized at the time the blasting operation is to be performed. The pressure of the charge within the cartridge IIJ increases'very rapidly and when the desired blasting pressure is attained, it will overcome the pressure of the charge of compressed air in the chamber 2| and will move the combined valve device 29 from its full line position of Figure 1 into its dotted line position of this disclosure. This movement of the valve device permits discharge of the blasting charge from the ycartridge I0 through the ports I3. The series of grooves 32 also establish communication between the compartment 2| and the discharge ports I3 with the result that the charge of highly compressed air is released from the chamber 2 The compressed air passes outwardly through the ports I3 with the blasting charge from the cartridge I0 and the compressed air, therefore, assists the blasting charge from the cartridge I0 in breaking down the material to be blasted. The release of the compressed air from the chamber 2| also removes from the compound valve device the force or energy which was employed to retain the two valve portions of this device in their closed positions.

Referring particularly to Figures ,4, and 6, wherein a modified form of indestructible discharge mechanism is illustrated, the character 40 designates a coupling member which is threadedly connected to the discharge end I of the cartridge I0. This coupling member 40 is provided, at a location intermediate its ends, with a series of obliquely arranged discharge ports 4I. A threaded connection 42 is provided between the coupling 66 and the cartridge, as illustrated. Outwardly of the discharge ports dI, the coupling 6I] is provided with a partition d3 which has.

formed therein a circular series of apertures M. This partition 63 acts as a guide for the stem o'f a valve which will be referred to at a later point.

Threadedly connected at B5 to the coupling 4I) is a casing member 46. This casing member has formed therein a partition 41 which is provided with a circular series of apertures d8. This partition 41 also acts as a guide for the stem of a valve device which will be referred to at a later point.

'I'he outer end of the casing member 56 has threadedly connected thereto, as at B9, a closure plug 50. This plug has formed therein the angularly arranged, communicating passages 5| and 52. The outer end of the passageway 5| is closed by a threaded plug 53. The closure plug 50 has formed therein a recess 56 which is threaded to receive the plug 53. The wall of this recess 54 is provided with a series of longitudinally extending grooves which will permit fluid to be fed around the plug 53 when the latter is backed away from the position in which it closes the outer end of the passageway 5|. By means of a suitable charging head, which is not illustrated as it forms no part of this invention, a suitable uid under pressure, such as compressed air, may be fed through the passageway 5| and 52 of the closure plug 50 for charging the chamber 56 which is formed in the casing member 56. This chamber 56 is divided into two parts by the partition 41 but these parts are in constant communication with each other through the series of apertures 56.

For the purpose of sealing the joint between the coupling member ill and the discharge end of the cartridge ID, a suitable packing ring or gasket 51 is provided. The joint between the coupling member 50 and the casing member 66 is sealed by the packing ring or gasket 58. packing ring or gasket 59 is provided for sealing the joint between the casing member 66 and the closure plug 50. y

A compound valve device is provided in this modification for closing the discharge ends of the cartridge Ii) and the chamber 56 in substantially the same manner as that' described in connection with the form of the invention shown in'Figures 1 to 3, inclusive. This compound valve device of Figures 4 and 5, however, diil'ers structurally from the previously described valve device.

For the purpose of closing the discharge end ot the cartridge I0, a valve head is provided and is adapted to seat against the extremity 6I oi' the end il of the cartridge I0. A valve stem 62, jointed at 6I, is provided for the valve head 36. 'I'his valve stem 62 is guided by the partition 49 and terminates at its outer end in a piston-like enlargement 64 which is located in the chamber A second valve head is'provided and functions to control the release of the compressed air from the chamber 56. This valve head 65 seats against the extremity 66 of the outer end portion of the coupling ed. l A tubular stem 6l is provided for the valve head 625. The bore oi this tubular stem Si sliclably receives the stem 62 of the valve head 5d. I

The outer end ci the tubular valve stern 61 has a tapered threaded connection 66 with a sleeve 69. i tapered threaded connection 16 is provided between the outer end o! this sleeve 69 and a cap 16. Thiscap is provided with a centrally apertured end Wall 1I, as clearly illustrated.

A diaphragm in the form of arubber disk 12 is clamped between the outer end ofv the sleeve 66 and the end'wall 1| of the cap 10. For the purpose of obtaining a tight clamping connection `between this diaphragm and the sleeve 69 and cap 16, the margin of this diaphragm is faced on opposite sides with the metal rings 13. These metal rings are intended to be surface bonded, as by vulcanization, to the margin of the diaphragm.

It will be seen that the outer end of the tubular valve stem 61, the sleeve 69, the cap 10 and the diaphragm 12 form a chamber for receiving the enlarged piston-like head 64 of the valve stem 62. A lost motion connection between the valve stem 61 and the valve stern 62 i's provided by this structure.

'I'he mode of operation of this form of the invention will be described as follows:

Prior to charging the cartridge I0 with the blasting medium to be employed, a suitable charge of compressed air is fed to the chamber 56. The pressure of this compressed air charge should be such that it will retain the two valve devices seated until the pressure of the blasting charge within the cartridge I0 reaches a desired working pressure at which time the blasting charge will overcome the pressure of the compressed air charge Within the chamber 56 for'opening the two valves. 'I'he charge lof compressed air fed to the chamber 56 functions to seat the valve 65 for preventing leakage of this compressed air from the chamber. The compressed air also applies pressure to the outer face of the piston-like head 65 of the valve stem 62. This application ofA force to the piston-like head 64 takes place through the' rubber diaphragm 12 and deflects or stretches this diaphragm, as shown in Figure 5, to take up a portion of the lost motion connection between the stems of the twovalves. The application of force to the piston-like head 64 moves the valve head 60 against its seat to close the discharge end of the cartridge i0. The indestructible release mechanism of this form of the invention is now in readiness for the cartridge I6 to be charged with its blasting medium. As explained above, this blasting medium may be of the typ fully disclosed and described in the aforementioned Ferrell patent. When the blasting charge in the cartridge i6 has been acted upon to raise the pressure of the same to a desired blasting pressure, the pressure of the charge will function to overcome the pressure of compressed air within the chamber 56. The valve 60 will be moved from its seat against extremity 6I of the cartridge. This outward movement of the valve head 69 and its rigid stem 62 causes the piston-likehead 64, of the stem 62 to move outwardly and take `up the lost motion connection between it and the valve stem 61. The diaphragm 12 will be straightened out, as .shown in Figure 4, and the piston-like head 64 will apply force against the end wall 1I of the cap 1l) through the medium of the diaphragm 12. It will be noted that the aperture formed'in this end wall 1I is of ,less diameter than the diameter of the p istan-liirey head 64 so that this end wall 'di of the cap 10 will baci: up or reinforce the diaphragm 12 against the pressure of the piston-like head 64.

fAfter this lost motion-connection is taken up between the two valve stems, the pressure of the blasting charge within the cartridge I6 will move the valve head 65 away from its seat 66 for releasing the' charge of compressed air from the chamber 56. This charge of compressed air will pass outwardly through the discharge ports 4I along with the blasting charge from the cartridge I0. Figure 5 discloses the two valves 60 and 65 in their. closed positions in full lines and in their opened positions in dotted lines.

In the form of the invention disclosed in Figures 'I and 8, the blasting cartridge Il) has its discharge end 14 threadedly connected to one end of a coupling member 15. The remaining end 16 of this coupling member is threadedly connected to a casing member 11. A series of obliquely arranged discharge ports 16 are provided in the coupling member 16 at a point intermediate its ends.

The outer end of the casing member 11 is threadedly connected at 19 to a plug 60 which functions to close the end of the casing member. Passageways 6i `and 62 are provided in the closure plug 66. The iextremity of the passageway 62 is provided with a closure 83 which is threadedly connected to the plug 60 and cooperates with grooves 64 for permitting compressed air, or 'the like, to be fed into the chamber 85 formed in the casing member 11, in the manner described in connection with the form of the invention illustrated in Figure 4. l I

A packing or gasket 86 is provided for sealing the connection between the cartridge I0 and the coupling member 15. A packing ring or gasket 61 is provided for sealing the connection between the casing member 11 and the closure plug 60.

A compound valve device, designated in its entirety by the reference character 88, consists of a valve head 89 which is adapted to seat against the extremity 90 of the discharge end 14 of the cartridge I0. This valve head 89 is rigidly connected by the stem 9| to a second valve head 92 which is adapted to seat against a shoulder 93,

preferably formed integrally with the inner wall v vided with a series of axially extending grooves 95. Figure 8 discloses the grooves 95 inthe periphery of the valve head 92. It is to be understood that the grooves 94 in the valve head Il will have the sameappearance when viewed from the' outer end of said head.

It will be appreciated that the chamber 85 of the casing member 11 is to be charged with a compressed fluid, such as air and that the pressure of this compressed air will bear against the inner face of the valve head 92 for forcing this valve head to seat against the shoulder. 93 for confining the charge of compressed air within the chamber. This seating movement of the valve head 92 is to be employed for seating the valve head 89 against its seat 90 for the purpose of' confining the blasting charge within the cartridge l until the pressure of this charge reaches a predetermined value with respect to the pressure of the charge within the chamber 85. When this pressure ratio is reached, the blasting charge in the cartridge 'l0 will overcome the charge of compressed air in the chamber 85 for moving both valves oi of their seats. The unseating of these two valves will permit the blasting charge from the cartridge l0 to be released through the discharge ports 18. The

grooves

94 and 95 formed inthe peripheries of the valve heads 89 and 92 will permit the charge of compressed air to be released from the chamber 85 for passage through the ports 18.

It will be appreciated that when produced in quantities, it will be impossible, due to normal manufacturing tolerances, to have both valve heads simultaneously engage their respective seats with uniform sealing effects unless some adjustment is permitted. Adjustment between the two valve heads is not plausible because these heads are normally inaccessibly located within the coupling and housing members. In this structure, the desired adjustment, therefore, is to be brought about between the two valve seats. The coupling member 15 is intended to be connected to the discharge end 14 ofthe cartridge in a non-adjustable manner. That is, the valve seat SG, formed by the cartridge l0, is intended to be fixed relative to the coupling member 15. The Avalve seat 93 for the valve head 92 is intended to be fixed relative to the casing member '17. By accomplishing an adjustment between the coupling member 'l5 and the casing member Tl, the desired adjustment between the two valve seats may be accomplished. For that reason, clearance, as at 9E. is provided between the opposed faces 91 and 98 of the casing member 17 and coupling member 'l5 respectively. This clearance will permit of relative adjustment between the members l and 11. A locking nut or ring 99 is provided for retaining the coupling and casing members in their desired adjusted positions.

To determine the adjustments necessary between the coupling and casing members, the chamber 85 may be charged with compressedair, or the like, at a time when the coupling member 'l5 and its cartridge I0 are backed away from the casing member Tl. The valve head 92, therefore, will be permitted to properly engage its seat 93. The cartridge I0 with the coupling member 'i5 then may be moved or adjusted toward the casingmember 'I1 until the valve head 89 tightly engages its seat 90. To determine whether the valve head 89 is tightly and completely engaging its seat 99, the cartridge I0 may be preliminarily charged with a compressible fluid, such as air. After the proper adjustment has been made, the lock nut 99 may be tightened against the surface 91 of the casing member 11 for maintaining this adjustment. The mechanism then will be ready for repeated use without further adjustment being necessary.

It will be appreciated that with the three forms of indestructible release devices, the same general principles are involved. These consist of the provision of a compound valve device which will function to retain a blasting charge within a cartridge and a valve controlling charge of a compressible uid within an auxiliary chamber. When the pressure of the blasting charge within the cartridge reaches a predetermined value with respect to the pressure of the charge within the auxiliary chamber, the compound valve device will be operated for releasing the charges from both the cartridge and the auxiliary chamber. The control mechanism of each of these modifications is of such a character that it will not occupy any of the space formed in the blasting cartridge. This is very desirable because it leaves the entire interior of the blasting cartridge available for occupancy by the blasting medium and its associated mechanism. It further will be appreciated that these release devices operate on the principle of employing 'the pressure of fluid medium in an auxiliary chamber for counteracting the pressure of a uid medium in the blasting chamber until the pressure of said latter fluid medium overcomes the pressure of the fluid medium in the auxiliary or control chamber.

It is to be understood that the forms of this invention herewith shown and described are to be taken as preferred examples of the same, and that various changes in the shape, size, and arrangement` of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim:

1. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge the pressure of which is suddenly elevated to the desired blasting pres-L and a plunger in said chamber subjected to the pressure of the fluid and connected to said valve.

2. In combination, a cartridge having a chamber formed with a discharge opening and'adapted to receive a blasting charge the pressure of which is suddenly elevated to the desired blasting pressure at the time of releasing the charge, a valve for controlling release of the blasting charge through said opening and movable in the direction of flow of the released blasting charge during opening movement, and means operated by the pressure of an independent fluid charge for opposing opening movement of the valve until the pressure of the blasting Acharge overcomes the pressure of said fluid charge, said means including discharge mechanism for the independent fluid charge.

3. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge the pressure of which is suddenly elevated to the desired blasting pressure at the time of releasing the charge, a valve for controlling release of the blasting charge through said opening, and means operated by the pressure of an independent fluid charge for opposing opening movement of said valve until the charge through said opening, means operated byh the pressure of an independent fluidA charge for opposing opening movement oi said valve-until the pressure of the blasting charge overcomes the pressure of said fluid charge, and means for releasing the independent fluid charge through said discharge opening at the time of releasing the blasting charge.

5. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge the pressure of which is suddenly elevated to the desired blasting pressure at the time of releasing the charge,

a valve for controlling release of the blasting charge through said opening and movable in the direction of ilow of the released blasting charge during opening movement, means operated 'by the pressure oi an independent uid charge for opposing opening movement of the valve until vthe pressure of the blasting charge overcomes the pressure of said fluid charge, and valve vmeans actuated by opening movement of the iirst valve for releasing the independent iiuid charge at the time of releasing the blasting charge. A A

6. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge the pressure of which is suddenly elevated to the desired' blasting pressure at the time o! releasing the charge, an auxiliary chamber having a discharge `opening and adapted to receive a fluid charge under pressure, a valve device for controlling release of the blasting charge from the cartridge chamber and the iiuid charge from the auxiliary chamber, and means subject to the iiuid charge in the auxiliary chamber for actuating said valve device to retain both of said charges coniined .in their respective chambers until the pressure of the blasting charge reaches a predetermined value relative to the pressure of the iluid charge, whereupon the blasting charge'will actuate the valve device for releasing both charges.

7. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge the pressure of which is suddenly elevated to the desired blasting pressure at the time of releasing the charge, an auxiliary chamber having a discharge opening and adapted to-reoeive a fluid charge under pressure, means comprising a valve for each oi said discharge openings for controlling release of the charges from both chambers, and means subject to the iluid charge in the auxiliary chamber for actuating said valve means to retain both oi' said charges conned in their respective chambers until the pressure of the blasting charge reaches a' predetermined value relative to the pressure of the iluid charge, whereupon the blasting charge will actuate said valve means for releasing both charges.

8. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive Aa blasting charge the pressure 0I Which is suddenly elevated to the desired blasting pressure at the time of releasing the charge, an, auxiliary chamber having a discharge opening and adapted to receive a iluid charge under pressure, coupling means for connecting said chambers and having a series o'f radial discharge ports, a' valve device for controlling release of the blasting valve device for releasing both charges into saidcoupling means for simultaneous discharge through said ports.

9. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge'the pressure of which is suddenly elevated to the desired blasting pressure at the time of releasing the charge, and a self-contained, unitary control device adapted to be located outwardly of and detachably connected to said cartridge adjacent said discharge opening for controllingrelease oi' the blasting charge from said chamber, said means including dual valve mechanism. 1

10. In combination, a cartridge having a chamber formed with aI discharge opening and adapted to receive a blasting charge the pressure of which is suddenly elevated to the desired blasting pressure at the time of releasing the charge, and a self-contained fluid pressure operated unitary 'control device adapted to be detachably connected to said cartridge and positioned entirely outside said chamber for controlling release of the blasting charge from said chamber, said means including a compound valve device.

. 11. A self-contained unitary control device adapted to be detachably coupled to the discharge end oi' a blasting cartridge to effect release of the cartridge charge, comprising a valvefor retaining the blasting charge in the cartridge and movable away from the cartridge in opening, a chamber for receiving and confining a fluid charge under pressure and means in said chamber subject to the pressurel oi the fluid charge for retaining said valve closed until the pressure of the blasting charge reaches a desired value relative to the pressure of the iluid charge.

12. A self-contained unitary control device adapted to. be detachably coupled to and positioned entirely outside one end of a blasting cartridge to eifect release of the cartridge charge, comprising a valve for retaining the blasting charge in the cartridge, a chamber for receiving a iluid charge under pressure, means in said chamber subject to the pressure oi.' the fluid charge for retaining said valve closed until the pressure of the blasting charge reaches a desir-ed value relative to the pressure of the iluid charge, and means for releasing the charge of iiuid charge under pressure and chargeable prior to coupling the device to a cartridge, means in said chamber subject to the pressure of the uid charge for retaining said valve closed until the pressure of the blasting charge reaches a desired value relative to the pressure of the uid charge, and a second `valve for releasing the charge of fluid from said chamberwhen the first valve is opened to release the blasting charge.

14. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge, the pressure of which is suddenly elevated to the desired blasting pressure at the time of releasing the charge, means for controlling release of the blasting charge through said opening, means operated by the pressure of an independent uid charge for opposing charge release operation of the rst mentioned means until the pressure of the blasting charge overcomes the pressure of said fluid charge, and means for releasing -the independent fluid charge at the time of operation of the blasting charge release, said two release means being capable of independent opening and closing movements.

15. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge, the pressure of which is suddenly elevated to the desired blasting pressure at the-time of releasing the charge, means for controlling release of the blasting charge through said opening, means operated by the pressure of an independent fluid charge for opposing charge release operation of the first mentioned means until the pressure of the blasting charge overcomes the pressure of said iiuld charge, and means actuated by the charge release operation of the first mentioned means for releasing the independent fluid chai-ge.

16. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge, the pressure oi which is suddenly elevated to the desired blasting pressure at the time of releasing the charge. means for controlling release of the blasting charge through said opening, means operated by,

the pressure of an independent uid charge for opposing charge release operation of the first mentionedmeans until the pressure of the blasting charge overcomes the pressure of said fluid charge. and valve means for releasing the independent fluid charge as a result of operation of the blasting charge release means. i

17. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge, the pressure of which is suddently elevated to the desired blasting pressure at the time of releasing the charge, a valve for controlling release oi the blasting charge through said opening and movable in the direction of ow of the released blasting charge during opening' movement, means operated by the pressure of an independent iiuid charge for opposing opening movement of the valve until the pressure of the blasting charge overcomes the pressure of said fluid charge, and means actuated b v opening movement of the valve for releasing the independent fluid charge at the time of re-` the pressure of an independent fluid charge for opposing charge release operation /of the rst mentioned means until the pressure of the blasting charge overcomes the pressure of said uid charge, and valve means for releasing the independent uid charge through said chamber discharge opening at the time of operation of the blasting charge release means.

19. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge, the pressure of `which is suddenly elevated to the desired blastpressure of the fluid charge, whereby the blasting charge will actuate the first mentioned means for releasing both charges.

20. A self-contained unitary control device adapted to be detachably coupled to and positioned exteriorly of the discharge end of a blasting charge receiving chamber for a blasting cartridge to effect release of the cartridge charge, comprising release means for the blasting charge in the cartridge, a chamber for receiving a uid charge under pressure, means in said chamber subject to the pressure of the uid charge for restraining operation of said release means until the pressure of the blasting charge reaches a desired value relative to the pressure of the fluid charge, and means for releasing the charge of fluid from said chamber when the blasting charge release means is operated to release the blasting charge.

2l. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge, the pressure of which is elevated to the desired blasting pressure to effect release of the charge, an auxiliary chamber having a discharge opening and adapted to receive a uid charge under pressure, a compound valve device for controlling release of the charges from said chambers through'their respective discharge openings, saidcompound valve device including lateral discharge ports common to both of said chambers for releasing to the atmosphere the charges released through said discharge openings, and means operatively connected to said valve device and subiect to the fluid charge in the auxiliary chamber for actuating said valve device to release the charges from both chambers when the blasting charge reaches the desired blasting pressure.

22. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge, the pressure of which is elevated to the desired blasting pressure to eiect release ofthe charge, an auxiliary chamber having a discharge opening and adapted to receive a uid charge under pressure, a valve seat associated with each dischargeopening, a coupling for connecting said chambers and having lateral discharge ports located between said valve seats, a compound valve device including a valve for each of said seats for controlling release of the charges from both of said chambers into said coupling, and means subject to the pressures ofA the charges in both of said chambers for actuating said valve device to release charges from both of said chambers, means for effecting uniform engagement of both of said valves against their seats by limited movement of said valves relative to each other, and means subject to the pressures of the charges in both said chambers for actuating said valve device to release said charges when said pressures bear a predeterminedv relation one to the other.

24. In combination, a cartridge having a chamber iormed with a discharge opening and adapted to receive a blasting charge, the pressure of which is elevated to the desired blasting pressure to effect release of the charge, an auxiliary chamber having a discharge opening and adapted to receive a fluid charge under lpressure, a valve seat associated with eachi discharge opening, a compound valve device including a valve for each of said seats for controlling release of the charges from both of said chambers, means for effecting automatic axial adjustment between the valves during seating movement for causing a uniform seating engagement, and means subject to the pressures of the charges in both of said chambers for actuating said valve device to release said charges when said pressures bear a predetermined relation one to the other.

25. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge, the pressure of which is elevated to the desired blastingpressure to effect release of the charge, an auxiliary chamber having a discharge opening and adapted to receive a iiuid charge under pressure, a valve seat associated with each discharge opening, a compound valve device including a valve for each of said seats for controlling release of the ,charges from both of said chambers, means for eiecting adjustment between said valve seats for causing uniform seating engagement of said valves, and means subject to the pressures of the charges in both of said chambers for actuating said valve device to release said charges when said pressures bear a predetermined relation one to the other.

26. In combination, a cartridge having a chamber formed with a discharge opening and adapted to receive a blasting charge, the pressure .of which is elevated to the desired blasting pressure to effect release of the charge, an auxiliary chamber having a discharge opening and adapted to receive a fluid charge under pressure, a valve seat associated with each discharge opening, a compound valve device including a valve for each of said seats for controlling release o! the charges from both oi' said chambers, a lost motion connection between the valves of said device for effecting uniform engagement oi' the valves against their seats, and means subject to the pressures of the charges in both of said chambers for actuating said valve device to release said charges when said pressures bear a predetermined relation one to the other.

27. In combination, a blasting cartridge having a plurality of ports through which the contents of the cartridge are to Abe discharged into the material to be broken down, said cartridge having a blasting charge receiving chamber and a control chamber to receive a iiuid charge under pressure, and means for effecting simultaneous discharge of the blasting charge and the fluid Icharge through all of said ports when the pressures of the charges in said chambers reach a predetermined' value relative to each other.

28. In combination, a blasting cartridge having a plurality of ports through which the contents of the cartridge are to be discharged into the material to be broken down, said cartridge having a blasting chargereceiving chamber and a control chamber to receive a iuid charge under pressure, and differential Afluid pressure valve means for eiecting simultaneous discharge of the blasting charge and fluid charge through all of said ports when the pressures of the charges in said chambers reach a predetermined value relative to each other. v

29. I n combination, a pair of chambers adapted to receive fluid charges under pressure, a valve seat for each chamber, a valve device including rigidly connected valves for both of said seats, said valves being operated for opening and closing movements by the differences in pressures in said chambers, and means for adjusting said valve seats' relative to each other to eii'ect uniform engagement of said valves with their seats.

30. Incombination, a pair'of chambers adapted to receive fluid charges under pressure, a valve seat for each chamber, a compound valve device including a valve for each valve seat, said valves each being subject to the fluid pressure in its respective chamber, a limited slidable connection between said valves to permit uniform seat engagement and to transmit the pressure applied-to each valve from its chamber to the valve of the other chamber, and means for sealing said slidable connection against leakage of said fluid from one chamber to the other.

31. In combination, a pair of chambers adapted to receive fluid charges under pressure,y a valve seat for each chamber, a compound valve device including a valve for each valve seat, said valves each being subjected to the iluid pressure in its valves in response to differences in' pressure be-v tween said chambers.

LEONARD D. MYERS.