US2330940A - Fire extinguisher - Google Patents

Description

Y Oct. 5, 1943.

J. W. WRIGHT FIRE EXTINGUISHER Filed Jan. 18, 1940 sheets-sheet 1 lllllllIlllllllllllillllllllllmlllIlIlllllllllllllllllulllll l g I -6o I E l Lm; lllllllllllllllIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIII NVN nventor Gttornegs Oct. 5, 1943. J. w. WRIGHT 2,330,940

FIRE EXTINGU'ISHER Filed Jan. 18, 1940 2 s'hets-sneet 2 y :invent r 7 f 9%@ (Ittornegs Patented Oct. 5, 1943 FIRE EXTINGUIS HER John W. Wright, Dayton, Ohio, assignorl to The Fyr-Fyter Company, Dayton, Ohio, a corporation of Ohio Application January 18, 1940, Serial No. 314,425

3 Claims. (Cl. 2520-64) This invention relates to re extinguishers.

It is the principal object of the invention to provide a fire extinguisher that is light in weight, relatively strong in construction and capable of withstanding normal usage, inexpensive to manufacture, and which will resist rupture and leakage at the seams under the application of high pressure over long periods of use, and under repeated applications of such pressure.

A further object is the provision of a Welded fire extinguisher casing of this character which is light in weight, easy to manipulate, and is fabricated from sheet metal having high strength providing a Welded construction free of rivets, and

having no solder, brazing materials, or the like.

It is a further object to provide such a fire extinguisher in which the interior of the casing is effectively protected against the corrosive action of chemicals by means of a thin, uniform protective coating overlying the entire interior thereof.

It is a still further object to provide such an extinguisher in which such coating is applied economically and uniformly by electroplating to form an electrolytically deposited protective coating thereon.

It is a still further object to provide a simple and satisfactory process for the economical manufacture of re extinguisher casings of the above character.

Other objects -and advantages will be apparent from the following description, the accompanying drawings, and the appended claims. y

In the drawings- Fig. 1 is a view in elevation of a finished extinguisher casing constructed in accordance with the present invention and showing in dotted outline the electroplating anode in position for forming the inner protective coating;

Fig. 2 is a partial view in section of the upper end of the casing showing the manner of securing the upper dome or closure member in position on the body shell;

Fig. 3 is a sectional view showing the manner of securing the bottom closure member in position;

Fig. 4 is a detail view in perspective showing al preliminary step in the forming operation in which the body shell is rolled into cylindrical form of predetermined diameter and temporarily secured;

Fig. 5 is a broken perspective view showing the manner in which the longitudinal seam is welded;

Fig. 6 is a diagrammatic view showing the welding operations and the controls therefor;

Fig. 'I is a sectional view through the Welded joint on an enlarged scale; and

Fig. 8 is a View showing a modified procedure for securing the bottom closure member in place.

Casings for fire extinguishers of the customary portable or manually operable type in commercial use at the present time are usually fabricated from sheet copper and are of riveted and soldered construction. While copper possesses desirable corrosion-resisting properties, it is not a particularly strong material and relatively heavier sections must be used to secure the required strength for an extinguisher casing. Where a riveted seam is used, it has been found necessary to solder over the head of each rivet and around the edges of the seam in order to assure a tight construction, and this operation has required considerable time and the use of a substantial quantity of solder.

interior of the casing to protect against corrosion under the action of the chemicals forming the charge, and this operation further adds to the expense of manufacture and to the weight, particularly as it is difficult to secure a uniform application of the solder and an excess is usually applied. Further the physical properties of the copper shell are such that if heated materially above the proper temperature for the application of the solder, definite impairment of its physical properties results, and consequently considerable care is necessary in the manufacture of such extinguisher casings. Such fire extinguishers are customarily made in two and one-half gallon size, and the construction as above described results in an extinguisher casing having substantial weight, making shipment more expensive and manipula- .tion and use more difficult.

In accordance with the present invention a material is utilized for the formation of the shell which has higher strength than the copper heretofore used and which will withstand equal or even greater pressure in a section of reduced thickness. Thus very satisfactory results have been secured from the use of such material in an extinguisher shell with a reduction in weight of approximately 25%, resulting not only in more economic use of materials, but reducing transportation and packaging costs and facilitating the handling of the extinguisher in actual use.

Further the invention provides for the forming and the fabrication of the shell and the finished -casing in such a manner as to completely dispense with the necessity for rivetng and soldering at the seams. This results in further economies in manufacture and provides a finished shell which is less likely to result in failure by reason of decomposition taking place in the area of the seams. In order to provide the desired resistance to corrosion under the action of the chemicals which are contained within the casing, a thin and substantially uniform protective surface is formed over the entire interior in place of the previous practice of applying a surface by tinning or soldering.

In accordance with this invention the added weight and expense of a coating of solder are eliminated and a uniform highly effective coating is formed upon the interior surface by electrolytic deposition. Such operation provides for securing a uniform application of the coating, over the entire interior surface of the casing including the welded seam areas, to a proper depth to afford protection against failure, and avoiding unnecessary waste of material. The coating preferably comprises a plating of nickel which is electrolytically formed from a suitable nickel solution. Since the seams of the casing are free of rivets and there is no solder or the like, the interior of the casing presents only the surface of the metal thereof and hence may be uniformly plated with a uniform, long lasting protective coating which will not be readily subject to decomposition. A highly satisfactory coating, capable of adequately withstanding the presence of the customary fire extinguisher chemicals over long periods of time is thus provided.

Referring to the drawings which disclose a preferred embodiment of the invention, the fire extinguisher casing is shown generally at I0. It comprises a main cylindrical body portion or shell II, an upper closure or dome member I2, and a bottom closure member I3. The upper dome member is formed with a filling opening Il, the neck I5 defining such opening having an exterior threaded portion I5 for removably receiving a cap thereon. The dome also contains a discharge fitting Il passing through the wall thereof and having a screen I8 upon its inner surface and a connection shown at I! for receiving flexible hose carrying a discharge nozzle, in the usual manner. The closure member I3 is preferably located somewhat above the lower end of the body shell II, and above an inwardly recessed flange 20, to provide a space for a handle 2 I. A supporting bead 22 is formed at the bottom rim upon which the extinguisher may be supported in standing position. It will also be understood that suitable hand brackets may be positioned upon the dome, and likewise a nameplate may be fastened to the surface of the extinguisher. v

In accordance with the present invention a flat sheet of metal is rolled into the generally cylindrical form of the shell II and received within one or more gage members 25. Such gage member has an internal diameter corresponding to the desired external diameter of the shell, and the the shell. suillcient in number to securely hold the same in the proper rolled or formed position. Usually about four such spot welding applications are found entirely sufficient. It will be noted that in this operation the metal sheet is brought in surface to surface contact with itself, and that there is no intermediate use of solder or other similar auxiliary material.

The cylinder is then subjected to a welding operation to securely weld the longitudinal overlapping joint along its entire length. In order to effectively secure such joint so that it will withstand the necessary high pressure conditions to which it is subjected in use it is important that it be secured at a number of closely spaced Y points along its length. It is also important satisfactory inherent resistance to decomposition,

two ends of the cylindrical shell are lapped upon each other to provide the overlapping joint as showny at 26, one edge of the shell material preferably being offset as shown at 21 in order to form a more uniform exterior surface upon the finished extinguisher. With the shell in such position it is temporarily tacked in place at the overlapping joint by suitable means such as by spot welding electrodes indicated at SII. These electrodes may be moved along the longitudinal joint, one outside and one inside the cylinder,

high strength, and also the ability to be electrically welded, that is. possessing suitable -characteristics of electrical resistance. A preferred material for this purpose consists of a coppersilicon alloy, containing primarily copper and silicon, the silicon comprising not morev than 3.5% of the material, and to which may be also added small quantities of one or more alloying elements, such, for instance, as zinc, tin, or manganese, the total quantity of these alloying elements being less than 2.0% of the entire material. One alloy which has been successfully used for this purpose consists of copper, 96.25%.; silicon, 3.25% and tin, 0.50%. Another alloy which has been successfully used consists of copper, 97.75%; silicon, 2.00% and tin, 0.25%.

While such alloy has the desired high tensile strength, of the order of 85,000 pounds per square inch, it cannot be heated to a high temperature without serious injury to such properties and marked reduction in such tensile strength. Accordingly therefore means are provided for producing a welding operation in spaced areas along the lapped joint, sumciently close to provide for securely sealing the joint upon itself and preventing any rupture or leakage thereof in use,

and so spaced that the heat generated during the welding operation is not suillciently great in the immediate vicinity of the weld as to result in damage to the physical properties of thev metal.

For this purpose the cylindrical body is moved relative to inner and outer welding electrodes, and the welding operation is controlled in an intermittet manner during such relative movement. 'I'hat is, the welding current is supplied intermittently to such electrodes, thereby providing welded areas alternating with non-welded areas. By suitably controlling the rate of such relative travel, and the frequency and duration of the periods of such current supply and nonsupply. proper regulation and spacing of the welded areas may be secured as desired. 'I'his results in producing seams in the welded areas, which may be as lclosely spaced as necessary to provide for adequately securing the overlapping parts together, and at the same time sufficiently separated to avoid development of such excesand several spot welds made along the lenh 0f 75 i165 0f the metal- Simultaneously the parts are der 42.

subjected to substantial pressure, so that during the entire feeding operation including both periods of Welding and non-welding, the overlapping edges are rmly pressed into surface to surface contact.

This is shown diagrammatically in Fig. 6 where the cylinder II is being moved relative to the inner and outer electrodes 35, 36, which are supplied with ow of welding current from the secondary of a step-down transformer 31. The primiry is energized from a suitable power source of alternating current (not shown), through a control indicated diagrammatically at 40. Such control is of the electronic control type using for example ignitron or thyratron tubes, providing for selection of the length of time during which the transformer is energized, and the corresponding independent control of the length of time during which it is not energized. By suitably regulating the control, the transformer may be energized and current caused to ow in the welding circuit for any desired period of time from a half cycle up, and this may be followed by a period of non-flow of welding current likewise variable from a half cycle up. With continuous movement of the electrodes relative to the cylindrical body it will thus be clear that seams or stitches may be formed in the metal of any desired width and spacing with respect to each other. An adjustable tap 4I on the transformer provides for adjusting the voltage and hence the amount of flow of the welding current. Also means are provided as shown at 42 in the form of an air cylinder for exerting pressure upon the electrodes and through them upon the parts being Welded.

As a specific example of conditions which have been found to produce highly satisfactory results in actual operations, a welding current of the order of 20,000 amperes has been used with a rate of travel of the cylinder relative to the electrodes of 36 inches per minute. Using a current of a frequency of 60 cycles per second, and with the control 40 set to provide welding current for three cycles followed by a like period of non-welding, this will result in a welded seam comprising a welded area of .03 inch in length followed by a space of .03 inch which is not welded. During these operations the welding electrodes are pressed toward each other with a total force of approximately 700 pounds by means of air cylin- As shown in Fig. 7 these welded areas 43 alternate with non-welded areas 44, producing the effect of seams or stitches in the metal, adequate to securely hold the welded parts together and yet so spaced from each other that the entire -body of the metal in the vicinity of the weld is not highly heated during the operation such It is preferred to subject these parts, after fabriand then quenched in water. This is preferably accomplished yby first fastening the dome I2 in position upon one end of the shell I I. The dome is provided with an outwardly extending ange portion which is telescopically received over the end of the shell, and a pair of welding electrodes comprising an internal wheel 46 and an external wheel 41 are brought into cooperative relation with respect to such flanged portion. Inner wheel 46 may be relatively large in diameter and supported from an arm extending through the open bottom end of the shell, the shell and the dome being preferably rotated around their longitudinal axis between the welding electrodes 46, 41. Such rotation may be effected by any suitable means, as, for instance, by causing the outer electrode 41 to be positively rotated by means of gear- wheels 48 and 49. Current is supplied to such electrodes in the same intermittent and controlled manner as above described with respect to the longitudinal seam, to secure such end closure member in place upon the shell in a similar effective manner, without the use of solder or rivets, and producing the stitch form of the nal welded joint.

Thereafter the bottom closure member I3 is slipped into position over the bead 2U, formed in the shell by rolling, the shell being slightly flattened to permit its introduction. Such member is likewise welded in place through the use of welding electrodes consisting of inner roller 5D and outer roller 5I cooperating with eachother under pressure in the manner above described. Roller 50 is made small enough to be passed through the filling opening I4, and is supported upon a suitable arm extending through such opening.

After the bottom closure is in position the casing is completely fabricated and presents a smooth and pleasing nished appearance showing the presence of the longitudinal seam and the peripheral seams 56 and 51 upon its outer surface.

In order to form the inner protective coating upon the surface of the extinguisher to protect the same against the highly corrosive chemicals which are used, an electrolytic deposit of noncorrosive metal is made throughout the entire interior surface of the extinguisher. 'I'his is effected by lling the casing with aA suitable electroplating solution, inserting an anode shown at 60 in dotted lines into the solution, and making suitable electrical connection to such anode and to the casing itself which forms a cathode, and supplying direct current thereto.

The coating which has been found to produce highly satisfactory results is a nickel coating. The anode is preferably formed of substantially pure nickel and is suspended in a solution containing 64 grams per liter of metallic nickel in the form of nickel chloride and nickel sulfate. As an example of satisfactory plating conditions, direct current of approximately amperes is passed through the solution for a period of about an hour. The passage of the current results in a rise of temperature of the solution and a change in the electrical resistance so that preferably the current ow is controlled by suitable regulating devices so that its value is maintained substantially constant. Likewise it is desirable to enclose the anode in a suitable bag or container of glass cloth or the like to prevent the settlement of sludge and foreign particles from the anode which would otherwise be deposited upon the bottom of the extinguisher.

Such electroplating operation provides for forming a substantially uniform coating having such thickness as to afford the proper protection against failure in use. It is found that it should not be less than about .0006 inch thick all over and to assure a satisfactory thickness of coating with some margin of safety it is preferred to make it approximately .001finch thick. Being substantially uniformly deposited o ver the entire interior of the extinguisher' including the welded areas, the joints and seams.' a thoroughly effective protection is thereby secured and without waste or unnecessary thickness of material at any point. It adds about 2 oz. in weight to the extinguisher and affords substantially better protection against corrosion than the former use of a tin lead alloy applied by a tinning operation `at the seams, over rivets, and the entire inner surface, which would usually add in the range of 2 to 4 pounds in extra weight.

Following the plating operationthe exterior surface of the shell may be finished in customary manner such as by polishing, enamel coating and the like and the extinguisher is then in form so that it is suitable for use.

Fig. 8 shows a somewhat modified form of construction in which the necessity for welding the bottom closure member I3 in place by means of an arm passing through the lling opening is avoided. In this arrangement a closure member $3 is positioned within the cylindrical body 60 with its convex face inwardly after which welding wheels 64 and 65 may be brought into cooperative relation with respect to the flangedl portion, both such wheels -being of suitable size and capable of being firmly supported and pressed towards each other under suitable pressure. Similar intermittent control during relative movement of the electrodes with respect to the parts to be welded is provided, so that an effectively sealed welded joint is provided in the manner above described. After welding, the projecting edge 6I of cylindrical body 60 may be turned inwardlyas indicated at 62 forming a flanged portion serving as a base or support for -the extinguisher to rest upon whenthe device is in the upright position and presenting a smooth rounded edge to prevent injury during operation. A suitable handle 88 may be atlixed to the bottom of the shell as indicated in Fig. 8 by suitable means such, for instance, as by means of spotwelding the handle 66 to the inwardly turned flange 62.

While the processes and articles herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise processes and articles, and that changes may be made therein without departing from the scope of the invention which is dened in the appended claims.

What is claimed is:

l. A re extinguisher of the vcharacter described comprising a substantially cylindrical tubular casing member formed from a sheet of copper silicon alloy having high strength and adapted to be electrically welded and having portions of said metal sheet overlapping along -a longitudinal edge, said overlapping portions of said metal sheet being in surface to surface contact in the cylindricalV surfacev and electrically welded directly to each other along the length of said seam. a dome member on said casing ex- Atending in one direction and having a flange portion thereof extending in the opposite direction and received l verlapping relation on one end of said tubular'- ng member, a bottom closure member on said casing and also extending in one 10 direction with a flange portion thereof extending in the opposite direction thereto and received on the othereend of said tubular casing member,

the flanges of said dome and said bottom closure members being electrically welded directly to the metal surface of said tubular casing member around theentire periphery thereof, each of the welds along said longitudinal joint and around the periphery of said closure members comprising a series of separated welded areas each of predetermined size and in such number as to provide for eifectively sealing the joint and being so spaced as to avoid excessive heating of the body of the metal sheet outside of said welded areas, said casing member having a protective coating upon the entire inner surface thereof including the welded areas of a character adapted to resist corrosion from the contents of the extinguisher.

2. A fire extinguisher of the character described comprising a substantially cylindrical tubular casing member formed from copper silicon alloy of high strength and adapted to be electrically welded and having portions of said metal sheet overlapping lalong a longitudinal edge, said overlapping portions of said metal sheet being in surface to surface contact in the cylindrical surface and electrically welded directly to each other along the length of said seam, a dome member on said casing extending in one direction land having a flange portion thereof, extending in the opposite direction and received in overlapping relation on one end of said tubular member, a. bottom closure member on said casing and also extending in onedirection with a ange portion thereof extending in the opposite direction thereto and received on the other end of said tubular member, the anges of said dome and said bottom closure members being electrically welded directly to the metal tire periphery thereof providing a smooth interior surface adapted for plating, each of the welds along said longitudinal joint and around the periphery of said closure members comprising a series of separated welded areas each of predetermined size and in such number as to provide for effectively sealing the joint and being so spaced as to avoid excessive heating of the body of the metal sheet outside of said welded areas, and the entire inner surface of said extinguisher. casing including' the welded areas having a plating of nickel electrolytically applied in substantially uniform manner thereto.

3. A iire extinguisher as defined in claim 2 in which the electrodeposited plating of nickel has a thickness not less than approximately .0006 inch.

JOHN W. WRIGHT.

surface of said tubular member around the en-v

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