US152598A - Improvement in linings for safes and other fire-proof structures - Google Patents

Description

U rrED STATES PATENT ()FFIC'E.

TVILLIAM H. BUTLER, OF BROOKLYN, NEW YORK.

IMPROVEMENT lN LININGS FOR SAFES AND OTHER FIRE-PROOF STRUCTURES.

Specification forming part of Letters Patent N0. l 52,598, dated June 30, 1874 application filed June 16, 1874.

had to the accompanying drawings, which form part of this specification.

In order that my improvement, which possesses all the valuable properties of the linings or fillings for fire-proof structures heretofore known, without their defects, may be clearly appreciated, I will here state that all the earths which are the best non-conductors of heat and a number of organic substances have been employed in combination with water andsalts containing water of crystallization for linings offire-proof structures. These have servedthe purpose of their design with various degrees of completeness.

The qualities requisite forthe best linin or filling for a fire-safe are, that the body-or main material shall be of the best non-conducting and ineombustible material known that it shall hold water in some form which, when it is subjected to a high heat will pass oif gradually in the form of vapor or steam, tocarry ofl heat not only from the interior of the safe, but to reduce the temperature of the outer iron casing, and protect it from burning and melting; that, also, in the last-named condition, acid vapors shall not be liberated with those of the Water and cause corrosive damage, not only to the metallic part of the safe, but to the interior contents or property placed there for preservation; that the lining shall not rust the iron inclosure with which it is in contact; that it shall not give oit' moisture and thereby cause dampness within the safe or vault, causing books and other valuables to mildew or mold that it shall not shrink or expand to such an extent, in the one case, as to strain the sides of the safe, or, in the other, as to leave vacant spaces; that it should give firmness and solidity to the structure.

All these qualities should be permanent to the fillingor lining during the natural use of the safe or structure.

Previous to my improy'ement which I am about to describe, there was no lining or filling known or used which possessed all the qualities essential to a proper lining, as those I have above mentioned. ()ne of the first inventions of fire-safe filling or lining for which Letters Patent were granted by the United States was that of Mr. Fitzgerald. This consistedof plaster-of-paris mixed with sufficient water tocause it to set or harden, and the interposition of sheets of mica between it and the iron walls, with which the mixture would otherwise comein contact. He also mixed mica with the plaster while it was in the pasty condition, so that when it hardened the mica became a part ofthe linin There had not, previous to the improvement which I shall herein describe, been a better lining than that of Mr. Fitzgeralds, except that the inner chamber inclosed by it was damp, and property placed within it became damaged from this cause. After a time, however, when it stood ina warm, dry atmosphere, it lost thelargerportion of its water, and then became impaired in fireproof quality. Aserious difficulty was that it rusted the iron of the safe rapidly, rendering the iron worthless. The various inventions since made in linings have been for the purpose of remedying the defects found in the use of the Fitzgerald lining. It was to remedy the dampness of the interior of the safe mainly that dry clay, plaster-of-paris, dry and other earthy substances were employed with lumps of alum and other crystalized salts holding a large proportion of their weight of water of crystallization, to be given offor liberated in case of fire. A num-' her of patents have been granted by the UnitedStates for this class of linings for fireproof safes, and they are each and all a kind of compromise with the defects of the Fitzgerald filling which I have above described.

Plaster-of-paris and calcined clay both absorb moisture from the atmosphere, and become damp duringa timeproportionate to the damp ness of the atmosphere in which they are placed. The alum or other deliquescent salt becomes gradually dissolved when mixed with plaster or cement, and then absorbed by the earth of the lining, when the rusting of the iron walls commences, and ultimately a damp and rusty safe is the result of the slow but certain process. In case of fire, too, the acids evolved from the salts with the water cause damage to the property stored in the chambers of the safe, even when the heat has not been sufficient to reach it. There is no better non-conductor of heat that is incombustible than plastcr-of-paris, which it is practicable to use for the lining of fire-proof structures. Therefore, in my improvement, I prefer this material as the basis or main ingredient of the lining, and I have retained in my improvement all the valuable qualities of the invention of Mr. Fitzgerald, and have remedied all its defects.

I take powdered or ground gypsum, calcium sulphate, and heat it till its water has passed ofi' and it becomes plasterof-paris. I next make a heavy solution of calcium chloride in water, and mix it with the plaster-of-paris in quantities sufficient to form a plastic massdensity of 15 to 30 of the alkali glass will answer this I place between the walls of the inner chamber of the safe and the outer walls or outside inclosure. The plastic mass is made to fill all the interstices, and after a few hours it sets or hardens firmly, adding to the solidity of the safe, and holding sufficient water to be given off slowly in the form of vapor or steam in case it is subjected to fire, and thereby reducing the heat interiorly, and preventing the outer iron walls from burning and melting. The calcium-chloride solution does not rust iron, and when in this condition it does not part with any of its water; therefore the inner chamber of the safe is dry; and however long the safe may have been used, its walls will not have become porous from rust, nor will the lining have lost its water, and the safe will have remained whatis termed a dry safe.

I prefer the lining precisely as I have just described it; but for some purposes calcined clay, kaolin, and other earths which will not be acted upon by the chloride, or which will not affect it, but which will remain neutral and permanent, may be mixed with the plaster-of-paris, dry, and the mixture treated with the solution of calcium chloride precisely as when the plaster-of-paris is used alone.

I will here add that I have obtained very good results from the use ofhydraulic cement, or that of Esopus, and the Berlin cement, used alone with the calcium-chloride solution, and

by mixing them with the pl aster-of-paris, and proceeding as I have described in the other cases. These cements, however, are not as good non-conductors of heat as plaster-ofparis, nor do they hold as large a quantity of solution of calcium choride. I will here mention that I have made linings of calcined clay and calcium-chloride solution alone: but such does not set, and the solution gradually settles to the bottom of the lining, creating inequality of moisture in the linin This, however, I have partly remedied by placing partitions or strips at short intervals in the lining, so as to forma series of shelves, which prevent the solution from finding its way below them. There are some cases, as that of large vaults, where the expense of the structure is of the first consideration, that this method will answer the purposes of its design very well. -I have also constructed linings for safes by substituting asbestus for plaster-of-paris, and proceeding with it precisely as I have just above described for clay alone. I have also mixed asbestus with plaster-of-paris, and proceeded as in the case when plastcr-of-paris was alone employed.

None of these last-described fillings are socompletely adapted to all the conditions a linin g is required to answer to as that of plasterof-paris alone, used with the solution of calcium chloride; and, therefore, as I have previously stated, I prefer this to either of the others.

1 find paper-pulp, charcoal, dry sawdust of wood saturated with calcium-chloride solution, and mixed plaster hydraulic cements in proper proportions to allow them to set, will stand a great degree of heat; also prevent rust and resist evaporation. I

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is

l. The fillings or linings for firesafes, vaults, and other fire-proof structures, formed of calcium chloride in combination with an absorbent or absorbents, substantially as described.

2. The use of calcium chloride with plasterof-paris, clay, lime cements, asbestus, or other earthy or organic materials which will not decompose the chloride, substantially as described.

In testimony that I claim the foregoing, I have hereunto set my hand this 9th day of March, 1874.

VI-LLIAM II. BUTLER.