GB1896 27197

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British Patent 27197 (1896) by Alfred Nobel
An improved manufacture of explosive compounds
Note: Application was filed ten days before Nobel died. The patent was granted posthumously to the executors of his will.

Original document is here.


British Patent N° 27,197 A.D. 1896

Date of Application, 30th Nov., 1896

Complete Specification Left, 30th Aug., 1897 -- Accepted, 30th Nov., 1897



PROVISIONAL SPECIFICATION.

An Improved Manufacture of Explosive Compounds.


I, Alfred Nobel, Chemist, Doctor of Philosophy, of 59 Avenue Malakoff, Paris in the Republic of France, do hereby declare the nature of this invention to be as follows:--

This invention relates to the manufacture of a smokeless explosive compound, consisting of layers of different chemical compositions, which are of such a nature, and are so arranged that the combustion is slowest in the outer layer, and increases inwards. The object of this invention is to modify the pressure in the powder chamber and adjacent parts of the guns in which the explosive compound is used, which pressure has a tendency to rise to a dangerous point, owing to the charge being confined in a contracted space.

I am aware that it has been tried to impart a progressive combustion to ordinary black powder by using, in the outer layers of the same, saltpetre crystals of larger size than in the inner layer; but in this way the desired result will not be obtained, owing to the fact that the larger crystals make the product more porous, and thus, as it is well known that the quickness of combustion of powder increases with the porosity of the same, it will easily happen that a result is obtained which is contrary to the one sought for. As a proof of the correctness of this statement, it might be mentioned that, by strong compression, it has been possible to make pieces of finely comminuted ordinary black powder of such a slow combustion that when ignited, it could be extinguished.

The explosive compound manufactured according to this invention differs essentially from the above mentioned powder, in that its progressive quality is obtained, in the latter case, in a purely mechanical way, by altering the size of the saltpetre crystals, while in the former case it is obtained in a chemical way, by introducing chemical substances in the outer layers of the compound, capable of modifying its explosive character.

In carrying out this invention, I use what is called ballistite, or an analogous explosive which is of such character that, during some stage in the manufacture, it is in a plastic state, and can then be pressed or rolled into any desired shape. The manufacture itself may be varied according to the nature of the explosive, the form it is desired to give the same, the ballistic properties of the fire-arm, the purpose for which it is intended, and the like. A few examples may be given in order to explain the way in which this manufacture is carried out. Of the different forms that may be given to this explosive, I may mention that of cakes or of tubes.

Charges in the form of cakes, which are specially suitable for large guns, are obtained by providing a thick rolled leaf or sheet, say A, of a composition of quick combustion, and two thinner rolled leaves, say B, of a slower burning composition. These leaves B are then placed one on each side of the leaf A, whereupon they are all rolled together or pressed in a heated state, or connected together by applying a suitable solvent, for instance, a solution of collodion in acetate of amyle, upon the surfaces, which are to be in contact with each other.

Charges in the form of tubes may be produced in same way as is usual for ballistite and similar kinds of explosive, only with the difference that the nozzle of the apparatus used in producing the tubes is arranged for simultaneously squeezing out several concentric layers of different compositions which, owing to their plasticity, will appear as only one coherent mass.

The following compositions will give good results:--

For A (the inner layer):--

60% Nitroglycerine
40% Nitrocellulose (of, for instance, 12% of nitrogen).

For B (the outer layer):--

45% Nitrocellulose
45% Nitroglycerine
10% Succinate of amylic oxide, or phthalate of methylic oxide, or any one of the many known non-explosive substances, or compositions of such substances, which dissolve nitrocellulose, and have, besides, a high boiling point, in order not to evaporate, as the properties of the explosive would then be altered. Such substances may be substituted the one for the other, as they all serve the same purpose, viz., to modify the rate of combustion of the explosive.

For large guns, it is preferable to manufacture the charge by using several layers having various rates of combustion, which increase towards the centre of the charge. Thus, the innermost layer will consist of a composition of quick combustion, intermediate layers of slower combustion, and outer layers of very slow combustion.

The advantages obtained by the use of charges thus prepared are:--

1. The possibility of using a great density of the explosive material, whereby the size of the cartridge, and thus also the size of the chamber, will be reduced to a minimum.

2. A lowering of the maximum pressure, whereby the strain on the breech, and on the hind portion of the gun, will be diminished, & erosions prevented to a great extent.

3. A greater effect per unit of weight of the barrel.

Dated this 30th day of November 1896.

NEWTON & SON,
Agents for the Applicant.

- - - - - - - - - -

COMPLETE SPECIFICATION

An Improved Manufacture of Explosive Compounds.


We, Ragnar Sohlman of Bofors, and Rudolf Liljequist, of 31 Malmskilnadsgatan, Stockholm, both in the Kingdom of Sweden, Executors of the will of the late Alfred Nobel, Chemist and Doctor of Philosophy, of 59 Avenue Malakoff, Paris, in the Republic of France, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement:--

This invention relates to the manufacture of a smokeless explosive compound, consisting of layers of powder of different chemical compositions, which are of such a nature, and are so arranged relatively to each other, that the combustion is slowest in the outer layer, and increases inwards. The object of this invention is to modify the pressure in the powder chamber and adjacent parts of the guns in which the explosive compound is used, which pressure has a tendency to rise to a dangerous point, owing to the charge being confined in a contracted space.

Attempts have been made to impart a progressive combustion to ordinary black powder, by using in the outer layers of the same, saltpetre crystals of larger size than in the inner layer, but in this way the desired result will not be obtained, owing to the fact that the larger crystals make the product more porous, and as the quickness of combustion of powder increases with the porosity of the same, it will easily happen that a result is obtained which is contrary to the one sought for. As a proof of the correctness of this statement, it might be mentioned that, by strong compression, it has been possible to make pieces of finely comminuted ordinary black powder of such a slow combustion, that when ignited it could be extinguished.

It has also been proposed to obtain the effect of progressivity by coating part of the grain with a comparatively slowly combustible material, in order to produce an increasing burning surface from the non-coated parts of the grain; but besides the inappropriateness of introducing into the powder chamber another material than powder, even if comparatively rapid of combustion, this manufacture has the inconvenience of producing gases of the highest temperature at the commencement of ignition. In the firing of explosives made according to the present invention, the gases produced at first are of a comparatively low temperature, as the substances apt to lessen the velocity of combustion, also tend to lower the temperature of the gases produced. This is of great consequence in respect of protecting the bore of the gun from erosion, for, with the high pressure during the first moments of combustion, any increase in temperature greatly increases the danger of erosion.

The explosive compound manufactured according to this invention differs essentially from both of the above mentioned powders, in that the progressive quality is obtained, in the black powder in a purely mechanical way by altering the size of the saltpetre crystals, and in the coated powder also, by a mechanical arrangement, viz., by limiting the surface to be ignited, in order to obtain a spreading fire, i.e., an increasing burning surface, while in the case of the present invention, it is obtained in a chemical way, by introducing chemical substances in the outer layers of the compound, capable of modifying its explosive character.

In carrying out this invention, the material preferably used is ballistite, or an analogous explosive, which is of such character that, during some stage in the manufacture, it is in a plastic state, and can then be pressed or rolled into any desired shape. The manufacture itself may be varied according to the nature of the explosive, the form it is desired to give the same, the ballistic properties of the fire-arm, the purpose for which it is intended, and the like. A few examples may be given in order to explain the way in which the manufacture is carried out. Of the different forms that may be given to this explosive, two examples may suffice, viz.: sheets and tubes.

Charges in the form of sheets, which are specially suitable for large guns, are obtained by providing a thick rolled leaf or sheet, which may be called A, of a composition of quick combustion, and two thinner rolled leaves, called B, of a slower burning composition.-- These leaves B are then placed one on each side of the leaf A, whereupon they are all rolled or pressed together in their plastic state, or joined together by applying a suitable solvent or glue, as, for instance, a solution of collodion in acetate of amyle or acetone, upon the surfaces, which are to be in contact with each other.

The sheets thus prepared are coiled up into the form of rolls of a diameter suitable to the cartridges to be filled. The coils of these rolls are kept apart by means of longitudinal strips of the like material, the object of the insertion of these strips being to form conducting passages for the fire from the fuse to act upon the surfaces of the coils.--The rolls thus formed may be of any desired length, and, when a heavy charge is required, it will be convenient to fill the cartridges with short rolls of corresponding diameter, placed one upon the other.

Charges for rifles may be produced in the form of tubes, in the same way as is usual for ballistite and similar kinds of explosive, only with the difference that the nozzle of the apparatus used in producing the tubes, is arranged for simultaneously squeezing out several concentric layers of different compositions, which, owing to their plasticity, will appear as only one coherent mass.

The following compositions have been found to give good results:--

I. For A (the inner layer):--

60% Nitroglycerine
40% Nitrocellulose (of, for instance, 12% nitrogen)
For B (the outer layer):--
45% Nitrocellulose
45% Nitroglycerine
10% Succinate of amylic oxide or phthalate of methylic oxide, or any one of the many non-explosive substances, known as 'moderants,' or compositions of such substances, which dissolve nitrocellulose, or can be otherwise incorporated therewith, and have, besides, a comparatively high boiling point, in order not to evaporate, as the properties of the explosive would then be altered. Such substances may be substituted the one for the other, as they all serve the same purpose, viz., to modify the rate of combustion of the explosive.

II. For A:--

Same as above.
For B:--
90% of composition A
10% of powdered starch or sugar, or analogous solid or semi-solid substances, rich in carbon and hydrogen.--

III. For A:--

80% of ballistite of following composition:--
50% Nitroglycerine
45% Nitrocellulose
5% Succinate of amyle or other aforesaid solvent or moderant.
20% highly nitrated wood meal, or pulverized Nitrocellulose of any other description.
For B:--
Ballistite of the same composition as for A, but without the aforesaid addition of Nitrocellulose.

For large guns, it is preferable, in manufacturing the charge, to use a great number of layers, with various rates of combustion, increasing always towards the centre of the charge. Thus, the innermost layer will consist of a composition of very quick combustion, intermediate layers of slower combustion; and outer layers of very slow combustion.

The advantages obtained by the use of charges thus prepared are:--

1. The possibility of using a great density of the explosive material, whereby the size of the cartridge, and consequently of the powder chamber, will be reduced to a minimum.

2. A lowering of the maximum pressure, whereby the strain on the breech, and on the hind portion of the gun, will be diminished, and erosions prevented to a great extent.

3. A greater effect per unit of weight of the barrel.

Having now particularly described and ascertained the nature of the said Invention and in what manner the same is to be performed, we declare that what we claim is:--

The manufacture of explosive compounds as above described, consisting in placing upon each other, by pressing, rolling, or otherwise joining together, layers of a plastic explosive compound of different chemical composition, as respects rate of combustion, in the order and for the purpose above set forth.

Dated this 30th day of August 1897.

NEWTON & SON,
Agents for the Applicants.