US3913604A

US3913604A - Piston-actuated fluid discharge device

Info

Publication number: US3913604A
Authority: US
Inventors: David E Hanson; Harry M Landers
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-07-13
Filing date: 1972-07-13
Publication date: 1975-10-21
Anticipated expiration: 1992-10-21

Abstract

A device for storing and discharging fluid under high pressure includes a toroidal storage chamber and a coaxial spool, in which is mounted two plugs. One plug is formed with a bored gas discharge passage into which a nozzle insert providing a square orifice extends; this passage is normally sealed by a prestressed diaphragm. The second plug provides a cylinder slidably supporting a piston, and mounts a header plug containing gasgenerating means for driving the piston to puncture the diaphragm for releasing the gas charge. The spool is threaded in both plugs; and the storage chamber, plugs, and header plug, are connected by circumferential welds which completely seal the device. The fluid storage chamber is sealed from the gasgenerating means by spaced flanges and an O-ring so arranged on the piston as to avoid pinching and thus cracking the O-ring.

Description

United States Patent Hanson et al.

PISTON-ACTUATED FLUID DISCHARGE DEVICE Inventors: David E. Hanson, 8' Oakridge Drive,

North Easton, Mass. 02334; Harry M. Landers, I56 Flaggler Drive, Marshfield, Mass. 02048 Filed: July 13, 1972 Appl. No.: 271,581

US. Cl. 137/68 Int. Cl B67b 7/24 Field of Search..., 222/5, 3; 280/150 AB;

References Cited UNITED STATES PATENTS 8/1966 Vuyosevich 222/5 5/1967 Sentz 222/5 [57] ABSTRACT A device for storing and discharging fluid under high pressure includes a toroidal storage chamber and a coaxial spool, in which is mounted two plugs. One plug is formed with a bored gas discharge passage into which a nozzle insert providing a square orifice extends; this passage is normally sealed by a prestressed diaphragm. The second plug provides a cylinder slidably supporting a piston, and mounts a header plug containing gasgenerating means for driving the piston to puncture the diaphragm for releasing the gas charge. The spool is threaded in both plugs; and the storage chamber, plugs, and header plug, are connected by circumferential welds which completely seal the device. The fluid storage chamber is sealed from the gas-generating means by spaced flanges and an O-ring so arranged on the piston as to avoid pinching and thus cracking the O-ring.

17 Claims, 4 Drawing Figures .3. Patent Oct. 21, 1975 SheetlofZ 3,913,604

\ mini I X r I NV ww mm mm mm mm US. Patent Oct. 21, 1975 Sheet2of2 3,913,604

PISTON-ACTUATED FLUID DISCHARGE DEVICE BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION Compact devices for discharging fluid stored under high pressure are employed in large quantity for such purposes as inflating marker bouys, life rafts, aeronautic and astronautic equipment, and the like. Because of the requirement to store fluid (liquid, gas, or a combination) at very high pressures, many known devices of this nature are subject to fluid leakage through imperfectly sealed joints. More reliable constructions tend to be excessively expensive to manufacture. Another common requirement of such devices is that the discharged fluid must be pure, and must contain no foreign matter or other fluid. It is therefore necessary to provide a sealing device which will not shatter into fragments when opened, and also to seal off the fluiddischarge path from the pyrotechnic gas-generating devices which are used for operating pistons or cutters for puncturing the sealing devices.

It is the general object of the present invention to provide an improved fluid discharge device which is reliable in operation, seals the fluid charge effectively against leakage, and is economical to manufacture. It is another object to provide a fluid discharge device with an improved discharge nozzle and seal arrangement. It is another object to provide a fluid discharge device with an improved actuator arrangement which affords effective sealing against mixing of actuating gas with the stored fluid. It is another object to provide an improved actuator arrangement which is unitarily constructed with the chamber body and which affords greater reliability of operation and improved economy of assembly. It is another object to improve the sealing of a fluid discharge device against loss of fluid pressure. Further objects and advantages will appear as the following description proceeds.

DESCRIPTION OF THE DRAWINGS While the specification concludes with claims specifically pointing out the subject matter which we regard as our invention, it is believed that a clearer understanding may be gained from the following detailed description of a preferred embodiment thereof, referring to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view in elevation of a preferred form of the fluid discharge device;

FIG. 2 is a bottom plan view prior to release of a fluid charge from the device;

FIG. 3 is a bottom plan view showing the device after the fluid charge has been released; and

FIG. 4 is a sectional plan view taken along line 4-4 in FIG. 1, looking in the direction of the arrows.

In the drawings, a piston-actuated fluid discharge device includes a pair of annular chamber shells l and 12, which mate along lips 16 and are joined by a circumferential weld 14. A toroidal fluid chamber is defined by the

shells

10 and 12 and by an annular cylindrical spool 60 received coaxially therein. A first plug member 76 and a second member 18 are threadedly engaged with the spool at 64 and 17, respectively. The strength of the fluid chamber is increased by seating the shells l0 and 12 under

circumferential flanges

20 and 78 formed in the respective plugs.

The spool 60 is so dimensioned that it engages the

plugs

18 and 76 and the shells l0 and 12. This insures that the threads 17 and 64 are fully engaged when the device is assembled, thereby achieving maximum bursting strength.

The shell 10 is secured and sealed to the plug 18 by a circumferential weld 21, while the shell 12 is similarly secured to the plug 76 by a circumferential weld 80. In assembling the device, the internal parts are first assembled with the

plugs

18 and 76, the welds 21 and 80 are formed, the

plugs

18 and 76 are threaded onto the spool 60 until the lips 16 meet firmly, and the weld 14 is made last.

The plug 76 is formed with a fluid discharge passage including a circular bore 82 and a threaded port 84 adapted for attachment to a discharge conduit. The interior 61 of the spool 60 communicates with the fluid storage chamber 15 through one or more openings 66 formed in the spool wall, and the fluid escapes through the bore 82 after the device is actuated. A sealing diaphragm 68 normally seals the bore 82, and is secured to the plug 76 by a circumferential weld 72.

It is necessary that the diaphragm open without shattering when it is punctured, so that no fragments will be discharged with the pure fluid charge. It has previously been discovered that a square nozzle form backing up the sealing diaphragm will promote a clean puncture and avoid fragmentation, when the diaphragm is prestressed with crossed linear indentations extending along the diagonals of the squared nozzle, such as shown at 75 in FIG. 2. According to previous practice, a squared nozzle was formed by broaching a plug such as 76; this is an expensive machining procedure. We employ a circular bore 82, which is relatively inexpensive to form, and provide a separate nozzle insert 70 which has a squared-off orifice portion 74 extending into the bore 82. The insert 70 is formed of thin sheet metal and can be stamped or otherwise formed by lowcost high-production methods. The orifice portion 74 is not truly square, as will be seen in FIG. 2, but has corners which are rounded to a radius less than half the width of the squared orifice. This aids in preventing shattering fragmentation of the diaphragm.

A piston or cutter 44, having a pointed tip 46, is slidably received in a cylinder 28, and is adapted to be driven downwardly as viewed in FIG. 1 to puncture the diaphragm 68 at the intersection of the linear indentations 75. When the piston is actuated, the pressure of the fluid charge in the chamber 15 and the spool 60 instantaneously rips the diaphragm along the indentations 75, and the quarters of the diaghragm fold against the walls of the orifice portion 74, as shown in FIG. 3, to release the fluid charge.

The cylinder 28 is formed with a locating flange 29 which rests in a stepped bore 27 formed in the plug 18, and abuts a circumferential seat 31. The use of the flange 29 rather than the commonly used weld bead at the top of the cylinder 28 provides greater reliability by virture of the greater mechanical strength of the flange. Also, the possibility of weld defects adversely affecting the reliability of actuator firing is eliminated. The dropin cylinder 28 is locked in place by the weld bead 23, which affords a more economical actuator construction. The weld bead 23 unitizes the chamber and actuator construction, and increases the reliability of the enformed with a first circumferential flange 48 which is of smaller diameter than the cylinder 28, and a second spaced-apart circumferential flange 52 which has substantially the same diameter as the cylinder and is slidably and conformably received therein. An O-ring seal 54 of rubber or other elastomeric material is received about a reduced portion 50 between the flanges 48 and 52, and seals the cylinder against fluid flow around the piston. if a pair of flanges each of the same diameter as the spool are used to-locate the seal 54 therebetween, there is a tendency for the seal to become pinched when assembled, and therefore to fail when the piston is actuated. Wehave discovered that the provision of a reduced-diameter flange 48 for locating the seal with respecttothe full-size flange 52 overcomes this problem.

To actuate the piston 44, a charge of gas-generating pyrotechnic mix 36 of anyv suitable composition is placed within a tubular ferrulev 34 received in the cylinder 28, behind the piston. A suitablepyrotechnic mixture has been developed for use in this application. Only a small amount of gas-generating material is needed, as the volume of the mix is required to multiply only a few-fold to drive the piston forwardly to engage theflange 48 against the bottom 30 of the cylinder, terminating the piston stroke.

The ferrule 34 serves not only to locate the piston. in its normal retracted position shown in FIG. 1, but also serves as a measure for the proper quantity of pyrotechnic mix 36. A header plug 22 is received in the bore 27 to enclose the charge 36. This plug receives electric leads 38 and 40; these are interconnected by a fuse or bridge wire 42 which is immersed in the charge 36, and serves to ignite it when an electric potential is applied to the leads by suitable external means (not shown) of a conventional nature.iThe charge 36 of pyrotechnic mix is placed within the ferrule 34.prior to assembly of the ferrule and plug 22 with the cylinder 28. lt is preferred to form the charge with a concave surface 37 adjacent to the flange 52.

To seal the, device against leakage of the gas generated by the charge 36, the

leads

38 and 40 are sealed byv a glass bead received in a bore 24 through the header plug 22. The header plug 22 is preferablyforrned of an alloy having substantially the same coefficient of thermal expansion as the glass bead 26, so that the glass-to-metal seal will not be damaged by changing temperatures encountered before the device is used.

The header plug 22 is permanently attached to the plug 18 by. a circumferential weld 23 at the entrance to. the bore 27. This insures against pressure leakage either from the fluid charged in the chamber 15, or from the gas generated by the charge 36. Equally important, this measure. strengthens the device at what might otherwise be a weak point, and overcomes a tendency in prior devices for the piston-actuating headerplug to be.

blown out when the device is operated, thus releasing the fluid charge and rendering the device ineffective.

Some additional advantages of the design are as follows. The design ofthe actuator permits the pyrotech 'nic device 36, 34, etc., to be inspected during the fabricationof the fluiddischarge device The cutter or piston 44 and the cylinder 28v are captured in position when the header plug 22 is located and welded in.place.-

This simplifies manufacture and secures the cylinder so that it cannot fly off when the actuator is fired. Thus the actuator is assembled as the deviceis fabricated.

" sealing highly secure.

Within the broader aspects of the invention, we contemplate its application to fluid discharge devices which are actuated mechanically rather than electrochemically, e.g., by driving thepiston directly rather than through the medium of gas/generated by an electricallyinitiated pyrotechnic mix.

Weclaim: v 1 A piston-actuated fluid-discharge device comprising, in combination:

means forming'a storage chamber for pressurized. fluid comprising an annular shell having central openings at opposite axial ends thereof, a pair of plug members received conformably in said openingsand welded circumferentially to said shell, and an annular cylindrical spool received coaxially within said shell and threaded at opposite ends thereof in said plug members, said spool being formed with an opening communicating the interior thereof with the interior of said shell; a first one of said plug members being formed with a fluid discharge passage of circular cross-section; a nozzle insert overlying an inlet end of said discharge passage and formed with a squared orifice portion extending into said passage; diaphragm meansoverlying said nozzle insert and normally sealing said storage chamber from said discharge passage; a second of said plug members being provided with means for puncturing said diaphragm means including cylinder-forming means extending axially within said spool, a piston slidably received in said cylinder-forming means and having a tip adapted 1 for puncturing said diaphragm means, and gasgenerating meansreceivedin said cylinder-forming means at an end-of saidpiston opposite said tip for driving said piston forwardly in said cylinderforming means for puncturing said diaphragm means; 1

said piston being formed with a first circumferential flange portion conformably and slidably received in said cylinder-forming means, and with a second circumferential flange portion spaced apart along said piston from said first flange portion, said sec- -ond flange portion being circumferentially spaced apart from said cylinder-forming means; and sealing ring means received about said piston between said flange portions and sealingly engaging said cylinder-forming means. I 2. A piston-actuated fluid-discharge device comprising,"in combina'tion:

means forming a storage chamber for pressurized fluidincluding an outlet plug member formed with a fluid discharge passage of circular crosssection; a nozzle insert overlying an inlet end of said discharge passage and 3 formed with a generally said orifice portion extending into said passage;

diaphragm means overlying said nozzle insert and normally sealing said storage chamber from said discharge passage;

means for puncturing said diaphragm means including cylinder-forming means, a piston slidably received in said cylinder-forming means and having a tip adapted for puncturing said diaphragm means, and means for driving said piston forwardly in said cylinder-forming means for puncturing said diaphragm means.

3. A device as recited in claim 2, in which said generally squared orifice portion is formed with corners rounded to a radius less than half the width of said orifice portion.

4. A device as recited in claim 2, said diaphragm being pre-stressed by means of crossed linear indentations extending substantially along each diagonal of said squared orifice portion.

5. A device as recited in claim 2, in which said chamber-forming means includes an annular shell having central openings at opposite axial ends thereof, a further plug member, said outlet plug member and said further plug member being received conformably in said openings and welded circumferentially to said shell, and an annular cylindrical spool received coaxially within said shell and threaded at opposite ends thereof in said plug members; said spool being formed with an opening communicating the interior thereof with the interior of said shell, and receiving said piston and cylinder-forming means therein in alignment with said diaphragm means.

6. A device as recited in claim 5, in which said means for driving said piston comprises gas-generating means received in said cylinder-forming means at an end of said piston opposite said tip, said further plug member being formed with an axial bore receiving said cylinderforming means, and a header plug including meansfor actuating said gas-generating means from an external location, said header plug being received conformably in said axial bore in said further plug member and being circumferentially welded thereto.

7. A device as recited in claim 2, said piston being formed with a first circumferential flange portion conformably and slidably received in said cylinder-forming means, and with a second circumferential flange portion spaced apart along with piston from said first flange portion toward said tip, said second flange portion being circumferentially spaced apart from said cylinder-forming means; together with sealing ring means received about said piston between said flange portions and sealingly engaging said cylinder-forming means.

8. A piston-actuated fluid-discharge device comprising, in combination:

means forming a storage chamber for pressurized fluid comprising an annular shell having central openings at opposite axial ends thereof, a pair of plug members received conformably in said openings and welded circumferentially to said shell, and an annular cylindrical spool received coaxially within said shell and threaded at opposite ends thereof in said plug members, said spool being formed with an opening communicating the interior thereof with the interior of said shell; a first one of said plug members being formed with a fluid discharge passage;

diaphragm means normally sealing said discharge passage, I v

a second of said .plug members being provided with meansfor puncturing said diaphragm means including cylinder-formingi means'ext'ending axially within said spool, a piston slidably received in said cylinder forming means and having a tip adapted forpuncturing said diap hragm means, and gasgenerating means received in said cylinder-forming means at an end of said pisto nropposite said tip for driving said piston forwardly in said cylinderforming means for puncturing said diaphragm means. t

9. A device as recited in claim 8, said second plug member being formed with a stepped axial bore providing a circumferential seat therein, said cylinderforming means extending within said bore and being formed with an annular flange abutting said seat, together with a header plug received in said axial bore and overlying said flange to capture said cylinderforming means in said second plug member, said header plug being circumferentially welded to said second plug member to securely retain said cylinderforrning means and said gas-generating means received therein in assembly with said second plug member.

10. A device as recited in claim 8, said second plug member being formed with an axial bore, together with aheader plug including means for actuating said gasgenerating means from an external location, said header plug being received conformably in said axial bore in said second plug member and being circumferentially welded thereto.

11. A device as recited in claim 10, said cylinderforming means being received in said axial bore in said second plug member, said header plug overlying and positioning said cylinder-forming means with respect to said second plug member.

12. A device as recited in claim 11, together with a ferrule received in said cylinder-forming means between said header plug and said piston to locate said piston in a retracted position spaced apart from said header plug.

13. A device as recited in claim 12, said gasgenerating means being received in said ferrule.

14. A device as recited in claim 8, said piston being formed with a first circumferential flange portion conformably and slidably received in said cylinder-forming means, and with a second circumferential flange portion spaced apart along said piston from said first flange portion, said second flange portion being circumferentially spaced apart from said cylinder-forming means;

and sealing ring means received about said piston between said flange portions and sealingly engaging said cylinder-forming means.

15. A device as recited in claim 8, said storage chamber-forming means being formed with a tapered orifice for filling said chamber with a charge of fluid, together with a taper pin sealingly engaged in said orifice with a force fit.

16. A device as recited in claim 8, said spool being of a length to abut said shell at each of said central openings at said opposite axial ends thereof.

17. A piston-actuated fluid discharge device comprising in combination:

means forming a storage chamber for pressurized fluid, said chamber being provided with a fluid discharge passage;

stepped axial bore providing a circumferential seat therein, said cylinder-forming means extendiri'g w within said bore and being formed with an annular flange engaging said seat, together with a header plug received in said axial bore and overlying said flange to capture said cylinder-forming means in said bore, said header plug being circumferentially welded to said chamber-forming means to securely retain said cylinder forming means and said gasgenerating means received therein in assembly with said chamber-forming means.

Claims

1. A piston-actuated fluid-discharge device comprising, in combination: means forming a storage chamber for pressurized fluid comprising an annular shell having central openings at opposite axial ends thereof, a pair of plug members received conformably in said openings and welded circumferentially to said shell, and an annular cylindrical spool received coaxially within said shell and threaded at opposite ends thereof in said plug members, said spool being formed with an opening communicating the interior thereof with the interior of said shell; a first one of said plug members being formed with a fluid discharge passage of circular cross-section; a nozzle insert overlying an inlet end of said discharge passage and formed with a squared orifice portion extending into said passage; diaphragm means overlying said nozzle insert and normally sealing said storage chamber from said discharge passage; a second of said plug members being provided with means for puncturing said diaphragm means including cylinder-forming means extending axially within said spool, a piston slidably received in said cylinder-forming means and having a tip adapted for puncturing said diaphragm means, and gas-generating means received in said cylinder-forming means at an end of said piston opposite said tip for driving said piston forwardly in said cylinder-forming means for puncturing said diaphragm means; said piston being formed with a first circumferential flange portion conformably and slidably received in said cylinderforming means, and with a second circumferential flange portion spaced apart along said piston from said first flange portion, said second flange portion being circumferentially spaced apart from said cylinder-forming means; and sealing ring means received about said piston between said flange portions and sealingly engaging said cylinder-forming means.

2. A piston-actuated fluid-discharge device comprising, in combination: means forming a storage chamber for pressurized fluid including an outlet plug member formed with a fluid discharge passage of circular cross-section; a nozzle insert overlying an inlet end of said discharge passage and formed with a generally squared orifice portion having rounded corners, said orifice portion extending into said passage; diaphragm means overlying said nozzle insert and normally sealing said storage chamber from said discharge passage; means for puncturing said diaphragm means including cylinder-forming means, a piston slidably received in said cylinder-forming means and having a tip adapted for puncturing said diaphragm means, and means for driving said piston forwardly in said cylinder-forming means for puncturing said diaphragm means.

6. A device as recited in claim 5, in which said means for driving said piston comprises gas-generating means received in said cylinder-forming means at an end of said piston opposite said tip, said further plug member being formed with an axial bore receiving said cylinder-forming means, and a header plug including means for actuating said gas-generating means from an external location, said header plug being received conformably in said axial bore in said further plug member and being circumferentially welded thereto.

8. A piston-actuated fluid-discharge device comprising, in combination: means forming a storage chamber for pressurized fluid comprising an annular shell having central openings at opposite axial ends thereof, a pair of plug members received conformably in said openings and welded circumferentially to said shell, and an annular cylindrical spool received coaxially within said shell and threaded at opposite ends thereof in said plug members, said spool being formed with an opening communicating the interior thereof with the interior of said shell; a first one of said plug members being formed with a fluid discharge passage; diaphragm means normally sealing said discharge passage, a second of said plug members being provided with means for puncturing said diaphragm means including cylinder-forming means extending axially within said spool, a piston slidably received in said cylinder-forming means and having a tip adapted for puncturing said diaphragm means, and gas-generating means received in said cylinder-forming means at an end of said piston opposite said tip for driving said piston forwardly in said cylinder-forming means for puncturing said diaphragm means.

9. A device as recited in claim 8, said second plug member being formed with a stepped axial bore providing a circumferential seat therein, said cylinder-forming means extending within said bore and being formed with an annular flange abutting said seat, together with a header plug received in said axial bore and overlying said flange to capture said cylinder-forming means in said second plug member, said header plug being circumferentially welded to said second plug member to securely retain said cylinder-forming means and said gas-generating means received therein in assembly with said second plug member.

10. A device as recited in claim 8, said second plug member being formed with an axial bore, together with a header plug including means for actuating said gas-generating means from an external location, said header plug being received conformably in said axial bore in said second plug member and being circumferentially welded thereto.

11. A device as recited in claim 10, said cylinder-forming means being received in said axial bore in said second plug member, said header plug overlying and positioning said cylinder-forming means with respect to said second plug member.

13. A device as recited in claim 12, said gas-generating means being received in said ferrule.

14. A device as recited in claim 8, said piston being formed with a first circumferential flange portion conformably and slidably received in said cylinder-forming means, and with a second circumferential flange portion spaced apart along said piston from said first flange portion, said second flange portion being circumferentially spaced apart from said cylinder-forming means; and sealing ring means received about said piston between said flange portions and sealingly engaging said cylinder-forming means.

15. A device a recited in claim 8, said storage chamberforming means being formed with a tapered orifice for filling said chamber with a charge of fluid, together with a taper pin sealingly engaged in said orifice with a force fit.

17. A piston-actuated fluid discharge device comprising in combination: means forming a storage chamber for pressurized fluid, said chamber being provided with a fluid discharge passage; diaphragm means normally sealing said discharge passage; means for puncturing said diaphragm means including cylinder-forming means, a piston slidably received in said cylinder-forming means and having a tip adapted for puncturing said diaphragm means, and gas-generating means received in said cylinder-forming means at an end of said piston opposite said tip for driving said piston forwardly in said cylinder-forming means for puncturing said diaphragm means; said chamber-forming means being formed with a stepped axial bore providing a circumferential seat therein, said cylinder-forming means extending within said bore and being formed with an annular flange engaging said seat, together with a header plug received in said axial bore and overlying said flange to capture said cylinder-forming means in said bore, said header plug being circumferentially welded to said chamber-forming means to securely retain said cylinder forming means and said gas-generating means received therein in assembly with said chamber-forming means.