US3848794A

US3848794A - Blast chamber

Info

Publication number: US3848794A
Application number: US00340133A
Authority: US
Inventors: W Howell
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1973-03-12
Filing date: 1973-03-12
Publication date: 1974-11-19
Anticipated expiration: 1991-11-19

Abstract

A blast chamber suitable for explosive welding of pipe is formed by a closed ended metallic vessel having an opening in each end through which pipe sections may be inserted for welding together. Water traps are provided on each end to seal around the pipe and the opening and contain and/or absorb at least partially the explosive force and gases. The water traps may be suitably formed at least in part of deformable and rupturable water-containing members or may be rigid means containing water through which the gases released by the explosion must pass.

Description

United States Patent [191 Howell 5] Nov. 19, 1974 BLAST CHAMBER 3,434,194 3/1969 Whittaker et al 29/4702 x [75] Inventor: giggam G. Howell, Lakewood, Prima'y Examiner Andrew R. Juhasz Assistant ExaminerRobert J. Craig [73] Assignee: Exxon Research and Engineering Attorney, Agent, or Firm-T. B. McCulloch; F. Donald Company, Linden, NJ. Parks [22] Flled: Mar. 12, 1973 [57] ABSTRACT [21] APPL 340,133 A blast chamber suitable for explosive welding of pipe is formed by a closed ended metallic vessel having an 52 US. Cl. 228/3, 29/421 E, 29/4702 Opening in each end through which P sections y 51 1m. 01 B23k 21/00 be inserted for welding together- Water traps are [58] Field of Search... 29/4702, 421 E, 486, 497.5; vided on each end to Seal around the P and the 72 131 5 2 3 opening and contain and/or absorb at least partially the explosive force and gases. The water traps may be 5 References Cited suitably formed at least in part of deformable and rup- UNITED STATES PATENTS turable water-containing members or may be rigid 2 367 206 H1945 D m 56 means containing water through which the gases reavls 3,024,526 3/1962 Philipchuk et al 29/4701 leased by the explosion must pass 3,206,845 9/1965 Crump 72/DIG. 56 20 Claims, 15 Drawing Figures 26 (WEIGHT) PATENTEI NOV 1 9 I974 SHEET 10F 3 lull-W miilllllll PATENTELNBVIQIW 3.848.784

SHEET 30$ 3 BLAST CHAMBER CROSS REFERENCES TO COPENDING APPLICATIONS This application is copending with and commonly assigned with the following applications 1. Ser. No. 398,941 filed Sept. 20, 1973, entitled DUAL HIGH EXPLOSIVE SHAPE DETONA- TION;

2. Ser. No. 252,641 filed May 12, 1972, for Robert H. Wittman, and William G. Howell, entitled WELDING OF HOLLOW CYLINDERS SUCH AS PIPE;

3. Ser. No. 252,678 filed May 12, 1972, for William G. Howell, Steve H. Carpenter, and Henry E. Otto, entitled EXPLOSIVE WELDING OF PIPE WITH EXPLOSIVE MEANS;

4. Ser. No. 252,820 filed May 12, 1972, for William G. Howell, entitled EXPLOSIVE WELDING OF PIPE. A similar explosive welding operation is disclosed in Ser. No. 252,821 filed May 12, 1972, for William G. Howell, Theodore Espinoza, and Robert H. Wittman entitled WELDING OF PIPE BY USE OF EXPLOSIVES now US. Pat. No. 3,806,020.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to a blast chamber for explosive welding. More particularly it is directed to a blast chamber for containment of the explosive forces, noises, debris, gases, and flames resulting from explosive welding. More specifically, the invention is directed to a blast chamber having water traps on each end for containment of explosive forces, noises, debris, gases and flames resulting from explosive welding of pipe.

2 The Prior Art It is known to weld pipe by means of explosives. It is also known to immerse the explosive in water or hydraulic fluid. However, explosive welding of pipe, while releasing an ominous appearing fire ball and some noise and debris, is largely harmless to personnel and the surrounding environment. In accordance with the present invention any danger from the explosion and from debris and the resulting noise has been largely eliminated or decreased which is advantageous from environmental and safety standpoints.

The following prior art was considered in connection with this invention:

US. Patents SUMMARY OF THE INVENTION The present invention may be briefly described as a blast chamber for explosives, particularly for use in explosive welding of pipe. A ferrous metal, such as steel and the like, chamber is provided having at least partially closed ends with co-axial openings in each end adapted for insertion of pipe sections into the chamber and to protrude therefrom. The two pipe sections are butted together and are suitably welded by placing around the abutting ends a collar having an explosive formed thereon and detonating explosive means and detonators connected to a source of electrical energy for setting off the explosive on the collar and thus forcing it against the abutting pipe ends to weld same together.

Water traps are provided on at least one end but preferably each end of the chamber around the openings and pipe to absorb the force of the explosion, the resulting noise, and also the fire ball released by the explosion. Gases and any debris are also absorbed by the water such that only quenched gases in the form of a fine mist or spray is ejected from the chamber by the explosive welding operation.

The water traps may take any of several forms such as containing means on each end of the chamber to support or contain deformable and rupturable bags or tubes forming a seal around the pipe and openings. The water traps may be open ended and may be closed around the pipe and into the chamber by deformable and rupturable means, and the like, or they may be comprised of individual water compartments.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial sectional view of the present invention with water traps on each end;

FIG. 2 is another embodiment showing a view taken along the line 2-2 of FIG. 1;

FIG. 3 is a view of the water chamber taken along the line 3-3 of FIG. 1;

FIG. 4 is a view of the seal disc of FIGS. 1, 2 and 3;

FIG. 5 is a view taken along the line 5-5 of FIG. 4;

FIG. 6 is a view showing the connecting means of FIG. 5;

FIG. 7 is a partial sectional view of another embodiment of the present invention;

FIG. 8 is a view taken along the line 8-8 of FIG. 7;

FIG. 9 is a view taken along the lines 9-9 of FIG. 7;

FIG. 10 is a view of the water absorbing means of FIG. 7;

FIG. 11 is a modification of the embodiment of FIG. 7;

FIG. 12 is a modification of a water trap of the present invention;

FIG. 13 is a view taken along the lines 1313 of FIG. 12;

FIG. 14 illustrates use of the present invention with a modified water trap; and

FIG. 15 is an enlarged view of the water trap of FIG. 14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS AND MODES WITH REFERENCE TO THE DRAWINGS Referring now to the drawing and particularly to FIGS. 1 to 6 in which identical numerals designate identical parts, numeral 11 designates a blast chamber provided with lift rings 12 for lifting same with a hoist (not shown). Chamber 11 is provided with water traps 13 on each end but which may be only on one end as desired. Attached to water traps 13 is yoke means 14, which carries roller means 15, which may be formed to fit on pipe sections 16 which are to be welded together explosively. Roller means may include an axle 15a and may be formed at least on its periphery with rubber, which may be synthetic or natural.

Coaxial openings

17 and 18 are formed in the end walls of traps 13 and the end walls of the chamber respectively, through which the pipe 16 extends. The openings exposed about pipe 16 are closed by plate means or discs 19 which are shown more clearly in FIGS. 4, 5 and 6.

In order to arrange the discs 19 in position on pipe 16 they are comprised of semicircular sections 19a and 19b connected together by a tongue and groove effect as shown. A central opening 20 is formed in the disc to fit about the periphery of the pipe 16 and in sealing contact therewith by means of a double adhesive strip 21. A ring 22 of double adhesive is affixed to one side of the disc whereby the disc may adhere to the wall of the chambers 13 in sealing relationship therewith. Additional sealing is provided by strips 23 which cover the joint line of the two sections. The discs are formed of a resilient material such as plastic.

The chamber 11 may be provided with an internal weight 26 which may be arranged externally and which may be fixedly or removably attached either internally or externally. This weight 26 serves to maintain the chamber 11 in a coaxial and upright position.

The chamber 11 is also provided as desired with a manhole cover 27 having hinges and locking means 28 comprising members 29 and pins 30. The cover 27 may be suitably sealed by gasket means and the like (not shown).

Water traps 13 may be filled with bodies of water 31 which are blown out when the mounded, stripped, or formed explosive mass 32 on collar 33 is detonated by ring detonating means 34 on mass 32 which is detonated by an electric current introduced through leads 35 connecting to a source of electric energy through opening 36 in cover 27 thus confining flames, debris, and the force in chamber 11 and causing the force and gases to blow out through water 31 in traps 13, the

discs

18 and 19 being ruptured.

FIGS. 7 to 11 show another embodiment in which only different parts to those of FIGS. 1 to 6 are described. In this embodiment the chamber 11 is acoustically insulated with usual acoustical insulation means 40 and the manhole cover 27 is also covered with similar means 40.

The weight 26 may have an opening 26a communicating with an opening 41 in chamber 11 closed with a threaded closure means 42. This opening 41 allows removal of any water which may accumulate in this embodiment of chamber 11.

In FIG. 7 the water traps 43 are provided with open ends 44 and windows 45. The traps 43 are suitably filled with split ring sponges 46 or other water absorbable material, either synthetic or natural, which are held in places by pins or bolts 47 which fit into openings 48 in water traps 43 and serve to hold the water absorbable material in place and form a seal.

In FIG. 11 the water traps 43a are identical to traps 43 except traps 43a are not provided with windows 45.

It is to be noted that the pipe sections 16 are arranged on support chocks 49.

FIG. 9 shows the yoke 14 and roller 15 as arranged with respect to FIGS. 7 to 11 since in these instances the water traps 43 and 43a provide partial support to the yoke 14 to carry the chamber 11.

Referring to FIGS. 12 and 13 a water trap 50 is provided with retainers 51 and which is open ended. Arranged in the water trap is water-filled bag 52, suitably constructed of rupturable and deformable material such as a closed plastic bag 52. For example, one used in garbage collection may be suitable. The bag need not be plastic but may be made of fabric suitably waterproofed which may be ruptured by the explosion from the welding operation. It will be noted that the bag 52 seals around the pipe section 26 and closes opening 53 into chamber 11.

In FIGS. 14 and 15 the chamber 11 is arranged on pipe sections 16 which have been welded together and is pulled onto or the pipe sections 16 is pulled into the chamber 11. In this embodiment deformable sleeves 60 are clamped about the pipe sections 16 and spaced thereon a prescribed distance from the abutting ends of the pipe sections which have a collar 32, explosive mass 33 and detonator means 34 arranged thereon. As shown the sleeves 60 are spaced apart a distance D which when the chamber 11 is moved into position the traps 61 are positioned about the sleeves 60. The sleeves are inflated by pressure such as applied through water connector means 61a as shown in FIG. 15, to expand the sleeves and send off the annulus between the pipe 16 and the inner wall of the trap 61 such that on detonation of the explosive mass 32 the bags 60 are ruptured, thus absorbing the explosive force and allowing only water and water vapor to be released, confining in chamber 11 substantially the force of the explosive, debris, flames, and reducing the noise of the explosive welding. This is particularly important in explosive welding of pipe at sea or in areas where the environment must be protected; particularly the present invention is important and useful in explosive welding of pipe at sea. When welding at sea or offshore, particularly in deep water, the chamber maybe used in a horizontal position or near horizontal position in shallow waters, vertical position, or in a position off the horizontal. In such cases the embodiments of FIGS. 7 to 15 may be particularly useful, or variations of such. In such latter cases, provision is suitably made for holding the chamber in a vertical or off horizontal position which maybe accomplished by the provision of suitable lift rings on one or both ends as shown in FIG. 1. Also, when welding at sea or offshore, the blast chamber may be arranged on the pipe laying barge off the horizontal position in deep water and may be fixedly or removably attached to the barge; in either case the pipe may move through the chamber rather than having the chamber move over the pipe as previously discussed.

The invention is also useful in welding in built up industrial and residential areas where environmental and safe conditions must be carefully controlled.

When the weld is made it will be understood that a mandrel will be used underneath the pipe collar to prevent collapse thereof and to absorb the shock. This mandrel may be moved along through the pipe and another section of pipe added thereon by pulling pipe through the blast chamber or moving the blast chamber along the pipe with the mandrel.

VARIABLES OF THE INVENTION The high explosive used in the mass or body on the collar and in the detonation explosive means may be any one of a number of high explosives such as, but not limited to, Detasheet C which is 63 percent by weight PETN, 7 percent by weight nitrocellulose and 30 percent polymeric materials and has a specific gravity of 1.48, a detonation velocity of about 23,000 feet per second, and is currently supplied on the market in rubbery sheet form, pentaerythritol tetranitate (PETN) with red lead and a binder composed of a mixture of butyl rubber and polymers of ,8 pinene, TNT, cyclomethylene (RDX), Pentolite which is a 50:50 mixture of TNT and PETN, amatol, a 50:50 mixture of ammonium nitrate and TNT, and other well-known high explosives and mixtures thereof which may be shaped, formed, or cast on the collar as will be described more fully hereinafter.

When using detonation means as described herein, explosives should be selected having detonation velocities within the range from about 15,000 to about 30,000 feet per second. Generally, explosives having detonation velocities within the range from about 22,000 to about 30,000 feet per second may be used in the detonation explosive means and explosives having detonation velocities within the range from about 15,000 to 23,000 feet per second in the body or mass. The explosive detonation means should have a detonation velocity substantially greater than the detonation velocity of the body or mass. Suitably a detonation ve locity of the detonation means about 25 percent to about 35 percent greater than the detonation velocity of the body or mass, within the broad range of about 15,000 to about 30,000 feet per second may be used preferably about 30 percent greater.

When using other detonation means such as described in copending applications Ser. Nos. 252,641; 252,820; and 252,821 are used, explosives having different detonation velocities as described therein may be employed.

The high explosive shaped or formed or otherwise placed on the collar such as by casting or molding may have a thickness at least adjacent its center about 200 percent to about 100 percent of the thickness of the sleeve or collar on which it is adapted to be placed at least adjacent its center and a thickness adjacent its ends about 200 percent to about 100 percent of the collar at least adjacent the ends of the collar. The high explosive may be shaped, formed, cast, molded, or layered and may be stepped, triangular, conical, truncated conical, or mounded in cross-section.

The size of the pipe which may be welded may vary from about 2 to about 48 inches in diameter with collars corresponding in size to weld the ends of the pipe together, but larger diameters of pipe may be used.

The amount of high explosive to be employed will vary, of course, with the size of the pipe collar and the detonation velocity of the explosive. However, the high explosive mass or body in the form of a ring on the collar may have a thickness at the center of the collar sufficient to provide from about 8 to about 16 grams per square inch down to a thickness of from about 4 to about 8 grams per square inch at the ends or edges of the collar. For example, in welding 12 inches pipe and employing Detasheet C explosive, the explosive would have a thickness at the center of the collar of about 10 to about 12 grams per square inch and at the ends or edges of the collar from about 4 to about 6 grams per square inch.

The high explosive detonation means may be in the form of a strip of high explosive at the center of the mass or body and may comprise from about 1 to about 10 percent by weight of the body and may be arranged in an indentation in the mass or body which may extend inwardly to the outer surface of the collar or sleeve. The indentation may be in the form of a notch and may have a V-shape.

The collar may have a thickness at the center substantially the same as or slightly larger than the wall thickness of the pipe sections tapering on its inner surface to about one-half the pipe sections wall thickness.

The center inner surface of the collar or sleeve may be from about one-sixteenth inch to about 1 inch in width, while the inner tapered surfaces may each be from about 45 percent to about 48 percent of the length of the collar. For example, a 12 inches pipe may require a collar about 4 inches in length while a 48 inches collar may require a collar of about 4 inches to about 6 inches length. A nominal 2 inches pipe may require a collar of about 2 inches length, whereas pipe of nominal 20 inches diameter may require a nominal 4 inches length collar.

The deformable and rupturable means and inflatable deformable and rupturable traps and bags are suitably constructed of sufficiently strong elastomers, rubber, both synthetic and natural, plastics, rubberized material such as impregnated fabric, such as canvas and the like or other impregnated, waterproofed fabrics and the like may be formed into inflatable bags, closed end tubes, and the like, but are sufficiently weak to be ruptured by the explosive force.

The nature and objects of the present invention having been completely described and illustrated and the best mode and embodiment contemplated set forth,

What I wish to claim as new and useful and secure by Letters Patent is:

1. Apparatus for containing an explosive force developed by the explosive welding of pipe sections which comprises:

a blast chamber having first and second at least partially open ends, in which said explosive is adapted to be enclosed;

means for closing said first and second ends at least partially such that there is provided an opening in said first and second ends sufficient for passage of pipe sections of selected size into abutting relationship in said chamber with said pipe sections extending longitudinally therefrom; and

means for containing a fluid arranged around at least one of said pipe sections extending longitudinally from said chamber to form a water trap around at least said one pipe section on at least one of said ends and substantially adjacent at least one of said openings for substantially containing the explosive force and noise resulting from the explosive welding of the pipe sections. 2. Apparatus in accordance with claim 1 in which the water trap comprises deformable and rupturable con-.

tainers.

3. Apparatus in accordance with claim 1 in which the water trap comprises first and second means adapted to contain water attached to said first and second ends at least below said openings.

4. Apparatus in accordance with claim 1 in which the water trap comprises:

a. a first and second means attached to said first and second ends at least below said openings; and

b. deformable and rupturable containers containing an aqueous fluid arranged in said means to seal said openings.

5. Apparatus in accordance with claim 1 in which the blast chamber has a scalable opening for permitting access to the interior of said blast chamber.

6. Apparatus in accordance with claim 1, including means for acoustically insulating said blast chamber.

7. Apparatus for containing an explosive force which comprises:

a blast chamber in which said explosive is adapted to be enclosed;

said blast chamber being formed to have first and second closed ends with an opening in said first and second ends sufficient for passage of pipe sections of selected size into said chamber and to extend therefrom;

first and second open ended water trap means arranged on said first and second ends to surround and extend from said openings;

deformable and rupturable means having a concentric opening, adapted to surround a pipe section extending through each of said trap means arranged on the open ends of each of said water trap means; and

means for introducing water into said water trap means.

8. Apparatus in accordance with claim 7 in which the blast chamber has a sealable opening for permitting access to the interior of said blast chamber.

9. Apparatus in accordance with claim 1 in which the blast chamber has deformable and rupturable means for containing a fluid on each of said ends arranged on said pipe sections to provide a seal at each of the openings around the pipe sections, when containing sufficient fluid to inflate said deformable and rupturable means into sealing contact with the portion of said blast chamber defining said opening and the pipe section which extends therethrough.

10. Apparatus in accordance with claim 9 including means for introducing fluid into the fluid containing means.

11. Apparatus in accordance with claim 1 including acoustical absorbing means operatively associated with the exterior of said blast chamber.

12. Apparatus in accordance with claim 1 in which the means to form said water trap comprises sponge means adapted to substantially seal when inflated with a fluid, any space between the pipe section and the portion of said blast chamber defining said opening.

13. Apparatus in accordance with claim 1 in which the blast chamber is provided with means for facilitating movement along at least one of said pipe sections.

14. Apparatus in accordance with claim 13 in which the movement means comprise rotatable means attached to each end of said blast chamber.

15. Apparatus in accordance with claim 14 in which the rotatable means are flanged wheels.

16. Apparatus in accordance with claim I in which the means to form said water trap comprises an opentopped vessel attached to at least one end of said blast chamber adapted to contain water and having an opening for receiving a pipe section protruding longitudinally from the blast chamber, and including means for sealingly closing any opening around the pipe section.

17. Apparatus in accordance with claim 16 including closure means at each end of said water trap which comprises a plurality of plate means adapted to sealingly engage around the pipe section, and means for holding said plate means together.

18. Apparatus in accordance with claim 17 in which the holding means comprise adhesive strips and the plate means comprises separable semicircular members which when connected together form a coaxial opening for receiving the pipe section.

19. Apparatus in accordance with claim 1 including means for weighting the blast chamber to maintain it in a substantially horizontal position when arranged horizontally on said pipe sections.

20. Apparatus for containing an explosive force which comprises:

a blast chamber having at least partially open first and second ends, adapted for containing the explosive therein;

means for closing said first and second ends at least partially to define openings therein respectively, sufficient for passage of predetermined pipe sections which extend longitudinally therefrom;

first and second open ended water trap means arranged at said first and second ends to surround and extend from said openings; and

deformable and rupturable means having an opening for surrounding said pipe sections extending through each of said water trap means and arranged at the open ends of each of said water trap means.

Claims

1. Apparatus for containing an explosive force developed by the explosive welding of pipe sections which comprises: a blast chamber having first and second at least partially open ends, in which said explosive is adapted to be enclosed; means for closing said first and second ends at least partially such that there is provided an opening in said first and second ends sufficient for passage of pipe sections of selected size into abutting relationship in said chamber with said pipe sections extending longitudinally therefrom; and means for containing a fluid arranged around at least one of said pipe sections extending longitudinally from said chamber to form a water trap around at least said one pipe section on at least one of said ends and substantially adjacent at least one of said openings for substantially containing the explosive force and noise resulting from the explosive welding of the pipe sections.

2. Apparatus in accordance with claim 1 in which the water trap comprises deformable and rupturable containers.

4. Apparatus in accordance with claim 1 in which the water trap comprises: a. a first and second means attached to said first and second ends at least below said openings; and b. deformable and rupturable containers containing an aqueous fluid arranged in said means to seal said openings.

5. Apparatus in accordance with claim 1 in which the blast chamber has a sealable opening for permitting access to the interior of said blast chamber.

7. Apparatus for containing an explosive force which comprises: a blast chamber in which said explosive is adapted to be enclosed; said blast chamber being formed to have first and second closed ends with an opening in said first and second ends sufficient for passage of pipe sections of selected size into said chamber and to extend therefrom; first and second open ended water trap means arranged on said first and second ends to surround and extend from said openings; deformable and rupturable means having a concentric opening, adapted to surround a pipe section extending through each of said trap means arranged on the open ends of each of said water trap means; and means for introducing water into said water trap means.

16. Apparatus in accordance with claim 1 in which the means to form said water trap comprises an open-topped vessel attached to at least one end of said blast chamber adapted to contain water and having an opening for receiving a pipe section protruding longitudinally from the blast chamber, and including means for sealingly closing any opening around the pipe section.

20. Apparatus for containing an explosive force which comprises: a blast chamber having at least partially open first and second ends, adapted for containing the explosive therein; means for closing said first and second ends at least partially to define openings therein respectively, sufficient for passage of predetermined pipe sections which extend longitudinally therefrom; first and second open ended water trap means arranged at said first and second ends to surround and extend from said openings; and deformable and rupturable means having an opening for surrounding said pipe sections extending through each of said water trap means and arranged at the open ends of each of said water trap means.