US2407500A

US2407500A - Container fok explosive shells

Info

Publication number: US2407500A
Authority: US
Publication date: 1946-09-10
Anticipated expiration: 1963-09-10

Description

Sept. 10, 1946. KRASNER ETAL 2,407,500

CONTAINER FOR EXPLOSIVE SHELLS Filed Feb. 5, 1945 IN V EN TORJ:

Jrrae/vsr Patented Sept. 10, 1946 UNITED STATES PATENT OFFICE Harold E. Krasiier andBcrtha Klausner, New York, N. Y.

Kp n'aubii sassy s, 1945, this N6. man

. 3 Claims.

The present invention is directed to a container particularly adapted for use in packing explosive shells and to a method of making the same.

Containers of this type are usually cylindrical in character and madein whole or in part of metal members. The shell fits tightly into the container in order that it shall be fixed relative thereto. It has been necessary to provide at the top and bottom of the container a member which fits tightly between the top and bottom of the shell and protects it from shocks. Heretofore steel members were used in order to hold the shell in place. Such members were adequate in that they had suilicient strength to withstand handling of the assembly and they were weather-resistant so that they did not disintegrate by exposure. However, such members had a number of disad vantages. For instance, they added substantially to the weight of the assembly and increased the cost of the container by a substantial amount. They required the use of steel, which has been scarce and critical. Also because of the relative stiffness of the steel member, it transmitted shocks to the shell. The steel being a heat conductor when the container was exposed to high temperatures, it quickly transmitted such temperatures to the shell with the consequent danger of accidental explosions. Also the steel member bea ing anelectrical conductor, it was capable of con- I ducting currents which might accidentally find their way in the vicinity of the container, suchja 's lightning; cables or the like and thus a' grave danger of accidental explosions resulted.

The presentinvention is intended and adapted to overcome the diflicultiesand disadvantages in.- he'rent in prior devices of the type above de scribed, it being among the objects of the present invention to provide a container for explosive shells having members at the top and bottom.

thereof for protecting such shells, which members are non-metallic; strong and weather-resistant.

It isalso' among the objects of the present invention' to provide such members which are resilient in character and which are capable of absorblng accidental, shocks and which are' electri call}; and heat insulating.

Itis still further among the objets of the s:

cut invntionto provide member's oith type d scribed which are fibrous in character, which are made of a number of materials and which are fireresistant and'cheap to produce.

Inprabticing the present invention, 1 provide a non-metallic member, usually in the form of a disk which is made of four thicknesses or plies of eachply consists essentially of a felted or matted mass ofifibers which have been suitabl packed and consolidated and specially treated. Each of the plies. isbonded ,to the adjacent plyby means of an adhesivewhich is a melted asphalt, preferably one made synthet.. ically from the residues of petroleum oil distillai. tion of an asphaltic base. oil. Such residues are brown or oxidized at a relatively high temperature in orderto provide the necessary properties in the resulting asphalt. Such an asphaltis applied while molten to the surfaces of each ply and the four plies are compressed together while the adh sive is still hot. Thisresults in. a firm bond forming a laminated material-inwhich each of the plies is resilient but has a sufficient hard ness and toughness to withstand all shocks and blows v U 1 In order to increase fire-resistance of the disk, the asphalt is mixed with finely divided mineral material which acts as a filler and reduces the infiammability cf the asphalt. Also each of the plies is impregnated with certain inorganic salts which have fire resis ting and fire-blanketing qualities. The-surface of the disk is also treated to give a smooth, non-porous surtace which is fire-resisting and also isoil repellant.

A disk made in accordance with the present in. vention has highly. desirable properties. For instance. it has a tensile strength of about 2500 lbs.- ner square inch, making it highly resistant against shock, while at the same time being suillciently resilient to absorb the force of such shocks. The ignition point of the,;mate rial is approximately 6509,1 and its dielectricstrength is fromr'to 10.0.

material. 7 body of conduct electric currents. ,fIhe material does not lose its strength over a wide range of tempera-- tures from 205E. below zero to 7150 F. It may be worked at, ordinary room. temperatures or higher without chipping or cracking. Furthermore, it is non-warping and is not distorted by exposure to weather, oil fumes or-the like. i

In the accompanying drawing constituting-a part hereof, and in which like reference characters indicate like parts,

i .1.5 i e b n lr ew f. a seen in the.

container madein accordance withthepresent invention, some parts being broken away for clearness;

Fig. 2 is an enlarged vertical cross-sectional.

view of one of the disks constituting the essence of the present invention, and

Fig. 3 is a top plan view of such a disk, some parts being broken away to show the internal structure.

The container 1, cylindrical in form, is made of any suitable material and it has a bottom 2 integral therewith. A cover 3 fits over the top thereof to complete the closure. On the bottom 2 is placed a disk 4 which is made of fibrous materials, as more fully described below. Shell 5 rests on disk 4 and the Sides thereof frictionally engage the sides of the container I. The nose 6 of the shell contacts with disk 1 of the same construction as disk 4. Disk 1 is fitted tightly into the sides of container I.

Each of the disks consists of four disks or sheets or plies 8 of suitable fibrous material. The fibers are relatively long, ranging from .25" to .5" in. in length. Principally the fibers are obtained from rags and cellulose, usually cotton, linen or the like. Preferably the fibers are treated with a solution of sodium hydroxide to cause chemical combination and then washed with an acid to remove excess caustic soda. This changes the surface of the fibers so that they may now be matted or felted. Preferably a mixture is made of about 75% of such fibers and about 25% of animal fibers, such as wool, fur, hair or the like. The mixture is felted by processes which are wellknown to form sheets of material.

Such sheets are impregnated with a water solution of a mixture of diammonium phosphate and ammonium borate. The salts are generally in equal proportions and the amount thereof impregnated into the sheets is from 1% to 2% b weight of the fibers present. For the present purpose,

it is preferable that in each molecule of salt there be at least two ammonium radicals. The impregnated sheets are then dried, leaving the intimate mixtures of salts 9 uniformly distributed throughout the same. The salts 9 have the property of preventing the penetration into the plies of oils, asphalt or the like, thus retaining the resiliency thereof. The salts also impart fire-resisting properties to the material.

The sheets are cut into disks of the proper size and each of the disks is sprayed with a hot molten asphalt mixture. Preferably the asphalt has a softening point of about 150 F. to 175 F. It is mixed with diatomaceous earth in the ratio of equal proportions by weight of asphalt and earth. No solvent is used and the thin film ID of the mixture is sprayed on each ply. Four plies are assembled and subjected to pressure while the asphalt is still hot and pressure maintained sufilciently long to allow cooling and solidification of the asphalt. Usually a pressure of about 40 to 60 lbs. per square inch is found to be suitable for the purpose of providing a unitary mass while still not injuring the resiliency of each P y.

The disk so formed is then provided with a coating l I on the upper and lower surfaces thereof. The coating is made of a mixture of 20% of asphalt having a high softening point in the neighborhood of 250 F. It is mixed with 80% of a filler which is mineral in character and fireresistant. The mixture is dissolved in a suitable organic solvent for the asphalt and it is sprayed or otherwise coated on the faces of the disk so that it penetrates a short distance into the same. The solvent is evaporated. The surfaces so treated are non-porous and because of the high percentage of inorganic filler is fire-resistant. This fire-resistance is thereby given to the entire disk.

It is important in the present invention that the relative proportions of the several constitu- 4 ents be within certain well-defined limits. The thickness of the asphalt layers i0 is small compared to the thickness of the disk. Preferably the thickness of asphalt I0 is about 1% of the thickness of the disk. The film or layer ll must be quite small and is in the neighborhood of onetenth of one percent of the thickness of the disk.

It is only by using a process such as is described in detail above that a disk is obtained which is fully capable of performing the functions required of it in protecting explosive shells both in transportation and any accidental detonation. The essence and the novelty of the present invention is that the disk or board of a combination of plastic and fibrous materials has such a strength that it may be used as a replacement for steel. It is also essential that the disk is suficiently lower in tensile stiffness or strength than steel so that it fully eliminates the possibility of building up with the sam an internal force great enough to cause the shell to explode prematurely. At the same time, the disk must be sufficiently tough or resilient to be used in place of steel and have a decided advantage over steel.

Although the invention has been described setting forth a single embodiment thereof and a single method of preparation of the board or disk, it will be apparent to those skilled in the art that certain variations in the details may be made within the scope of the invention. For instance, instead of cutting disks 8 from the sheets and then assembling the same, one may take the whole sheets, spra the same with molten asphalt l0 and consolidate the sheets into multiple ply boards. The boards may then be slightly warmed and punched to form the completed disk.

One may impregnate into each ply an organic material which is water and oil repellant. The ends of each disk may be sealed in the same manner as the faces thereof and sealed b films H. Other fillers may be used in place of diatomaceous earth, such as fullers earth, bentonite and the like. Instead of the phosphates and borates, one may use sulphates and tungstates of ammonia or mixtures thereof. The diameter of the disk may be changed relative to the thickness thereof for use in containers of different diameters but the relative thicknesses of the Several layers and films should remain without alteration.

These and other changes in the details of my invention may be made within the spirit thereof and the invention is to be broadly construed and not to be limited except by the claims appended hereto.

We claim:

1. In a container for explosive shells having a cylindrical case closed at one end, a fibrous laminated disk at said end, a shell on said disk and closely fitting the walls of said case, a second laminated disk on the top of said shell and fitted into said case, the improvement which consists in that each of said disks consists of four transverse plies of felted fibers, the major portion being cellulose fibers and the minor portion being animal fibers in the ratio of about rag fibers and 25% wool fibers, each of said plies being treated with a small amount of ammonium salts of inorganic acids to render the plies fire-resistant and oil repellant, a relatively thin cementing film of melted asphalt mixed with finely divided inorganic filler in the ratio of about 50% of asphalt and 50% diatomaceous earth sprayed on the meeting faces of said plies, said plies having been subjected to pressure while the asphalt is hot to 7 consolidate said disk, whereby the resiliency of said plies is retained, the outer faces of said disk being impregnated to a small depth by a solution in a volatile solvent of a mixture of a major portion of asphalt and a minor portion of an inert, finely-divided, mineral filler in the ratio of about 80 to 20, said disk being resilient, strong, and having a high dielectric value.

2. In a container for explosive shells having a cylindrical case closed at one end, a fibrous laminated disk at said end, a shell on said disk and closely fitting the walls of said case, a second laminated disk on the top of said shell and fitted into said case, the improvement which consists in that each of said disks consists of four transverse plies of felted fibers, the major portion be ing cellulose fibers and the minor portion being animal fibers in the ratio of about 75% rag fibers and 25% wool fibers, the length of said fibers being from .25" to .50", each of said plies being treated with from .5 to 2% by weight or ammonium salts of inorganic acids to render the plies fire-resistant and oil-repellant, a. relatively thin cementing film of melted asphalt mixed with finely divided inorganic filler in the ratio of about 50% of asphalt and 50% diatomaceous earth sprayed on the meeting faces of said plies, said plies having been subjected to pressure while the asphalt is hot to consolidate said disk, whereby the resiliency of said plies is retained, the outer faces of said disk being impregnated to a small depth by a solution in a volatile solvent of a mixture of a major portion of asphalt and a minor portion of an inert, finely-divided, mineral filler in the ratio of about 80 to 20, said disk being resilient, strong, and having a high dielectric value, said cellulose fibers having been treated with sodium hydroxide and washed.

3. In a container for explosive shells, a disk consisting of four transverse plies of felted fibers, the major portion being cellulose fibers and the minor portion being animal fibers in the ratio of about rag fibers and 25% Wool fibers, the length of said fibers being from .25" to 50", each of said plies being treated with from .5 to 2% by weight of ammonium salts of inorganic acids to render the plies fire-resistant and oil-repellant, a relatively thin cementing film of melted asphalt mixed with finely divided inorganic filler in the ratio of about 50% of asphalt and 50% diatomaceous earth sprayed on the meeting faces of said plies, said plies having been subjected to pressure while the asphalt is hot to consolidate said disk, whereby the resiliency of Said plies is retained, the outer faces of said disk being impregnated to a small depth by a solution in a volatile solvent of a mixture of a major portion of asphalt and a minor portion of an inert, finelydivided, mineral filler in the ratio of about to 20, said disk being resilient, strong, and having a, high dielectric value, said cellulose fibers having been treated with sodium hydroxide and washed.

HAROLD E. KRASNER. BERTHA KLAUSNER.