US1918906A - Safety device for containers for explosives, particularly explosive gases - Google Patents

Description

July 18, 1933.

H. GROHMANN SAFETY DEVICE FOR CONTAINERS FOR EXPLOSIVES, PARTICULARLY EXPLOSIVE GASES Filed May 5, 1930 /n venfor:

Patented July 18, 1933 misstemes;

HANS GROEEIANN QF I-IIBSGIEIFELDS, GERMANY SAFETY DEVICE FOR CONTAINERS FOR EXPLOSIVES, PARTICULARLY EXPLOSIVE' GASES Application filed May 5, 1930, Serial No.

This invention relates to a safety device for containers charged with combustible (explosive) substances, so that in the event of an explosion occurring this shall not extend to the inside of the container. 7

Inthe device according to this invention, there is interposed in the path of the combustible (explosive) substance or gas, a safety shield consisting of a quantity of some ma- 1o terial such as sand, quartz, metal or other material of such consistency thatthe recoil caused by an explosion will compress the heap, so that firstly it acts as an obstacle,"and secondly by absorbing and using up consid- 5 erable quantities of heat in the form of mechanical energy, it prevents the propagation of the explosion.

It is desirable to select for the composition of the compressible heap, materials which by undergoing physical or chemical changes can absorb still further quantities of heat.

According to the present invention, the heap is placed in front of the cross section of the pipe or vessel containing the explosive substances that it is desired to protect, and

it rests upon a plate perforated with small apertures and capable of resisting the bending strain caused by the high pressures due to an explosion, in such a manner that without preventing the free passage under normal conditions of the combustible materials (gases), it will, in the event of an explosion,

be mechanically compressed by the resulting shock, and will possibly also undergo a physical or chemical change, with the result that the mechanical compression will either wholly or for the greater part close up the crosssection to be secured and prevent the gas from passing through it, whilst at the same time a portion of the heat emitted by the explosion is absorbed in consequence of physical or chemical action upon the compressed heap. In this way not only is the container or pipe which it is desired to secure protected against the shock of the explosion wave itself, but it is also protected against the heat which otherwise would be conveyed by conductivity.

The physical absorption of that part of the heat of the explosion which is not ab- 449361, and in Germany July 24, 19 29.

sorbed by the work of deformation, may, for example be brought about in adequate degree by usingjas the filling substance a heap of particles of a metal in which the product of specific gravity, specific heat and heat conductivity is as large as possible, or alternatively by using a heap of particles of a substance that melts readily, for example, finely broken up sulphur, flour of sulphur, which under the action of the pressure caused by an explosion, whilst absorbing a certain amount of mechanical energy will become compressed, simultaneously beginning to fuse under the action of the heat of the explosion wave, thereby absorbing a large part of the o5 explosion in the form of fusing heat. The absorption of a part of the explosion heat by means partly physical and partly chemical is also feasible by the choice of a suitable filling substance, for example, if we se '10 lect ammonia alum, a salt containing up to 47% of water in the form of water of crystallization, with the result that the water in this substance is caused by the temperaure of the explosion heat to evaporate, thereby abso'rbing a portion of the explosion heat. In the device forming the subject of this application, the heat is held as a result of the constitution of the filling substance forming the interposed heap, either by conduction, fusso ing, evaporation of moisture, or some other means, and partly by the simultaneous compression (deformation) of the filling substance-itself.- This compression absorbs heat by transforming it into mechanical energy and brings about at the same time a more intimate contact between the hot explosion gases and the filling substance, thereby reacting favourably upon the interchangev of heat and finally closing up the passage against any further penetration of the explosion wave.

The accompanying drawing is partly an elevation and partly a vertical section of a container and provided with a safety device constructed and arranged in accordance with this invention.

In the embodiment of my invention here shown, a nipple N is'screwed gas-tight into the container to be protected. This nipple is provided with a screwed-on valve V and with the safety cartridge Q, consisting of a tube screwed on to the lower end of the nipple N, with a rigid perforated bottom P, and filled with a heap of some suitable substance such as aluminium filings, sand quartz or the like, which will be Compressed by the force of the explosion, thereby completely closing up the apertures in the bottom P.

On an explosion wave passing from outsidethrough the nipple N into the cartridge, the first thing to happen is that the heaped mate rial in the cartridge will be compressed. If anyhotexplosiongasesdomanagetopenetrate through the apertures in the bottom P, they must first find their way therefrom into the narrow ring shaped space between the covering of the cartridge Q and a metal sleeve M which surrounds it concentrically. This external sleeve surface M is however completely surrounded by the cooling substance so that any small portion of the residue of the hot gases that may have found its way through the apertures. in the bottom P of the cartridge Q, and into the ring-shaped space, will by that time be greatlycooled down, and it is only in this cooled state that it can pass from the upper edge of the ringspace through the closing-sieve T and so reach the interior of the cylinder. On emerging from the sieve T at the upper end of the cartridge these residual explosion gases will strike the metal surface of the container charged with the combustible substance and will thereby undergo a further energetic cooling process.

What is claimedr 4 1. A safety device for explosive gases or containers of explosive charges, comprising ing from an explosion and to thereby cut off the passage of the explosion gases to the container, and an'outer shell around and spaced from the cartridge shell, so that a narrow space is formed between the two closely arranged surfaces of said shells so that the residue of the hot explosion gases which may pass through the loose material must pass through this narrow space before it can enter the container.

2. Safety device according to claim 1, characterized by the fact that the ring-space surrounds-a cartridge constructed in the shape of atube and containing the heaped substance, so that the hot explosion gases traverse the heaped material within the cartridge in onedirection and the ring-space in the opposite direction.

Safety device according to claim 1, characterized by the fact that in order to protect thecontainer chargedwi-th explosive gases, the. latter is fitted with a screw-on nipple together with a tube-shaped extension screwed on to the nipple reaching into the interior of the container and carrying the safety device.

HANS GR OHMANN.

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