US1771826A - Automatic sprinkler and the like - Google Patents

Description

July 29, 1930. J TAYLOR 1,771,826

AUTOMATIC SPRINKLER AND THE LIKE Filed Feb. 25. 1926 lllm'lll INVENTOR. JZ'ay/ar l 'atentecl July 29, 1936 JOHN TAYLOR, or MANCHESTER, ENGLAND AUTOMATIC SPRINKLER AND,THE LIKE Application filed February 2 This invention relates to improvements in automatic fire extinguishing sprinklers of the type in which the sprinkler is normally held closed by means of atrangible vessel containing a liquid and is permitted to open, when suificiently heated, by the fracturing oi the vessel resulting from stresses induced in the walls of the vessel by the thermal eX- pansion of the liquid contained therein.

lhe improvement lies in the frangible vessel, andespecially in the combination producing a reaction between its liquid filler and its walls, due to the improved filler.

In order that a sprinkler of this type shall operate eii'ectively, it is essential that when the frangible vessel bursts it shall be shattered into small fragments so that no part of it shall remain to obstruct the tree opening of the head. Further, it is essential that the said frangible vessel shall be mechanically strong as a strut and maintain the sprinkler firmly closed against the pressure of the water in the sprinkler installation, and against the pressure to which it is otherwise subjected until it is called. upon to operate with an outbreak of fire. Prior to thedate of this -invention it h as been proposed to use a volatile liquid as the filling tor the frangible vessel which exerts force by the generation of gas when the expansion of the liquid has caused the vessel to burst; the energy out the rapidly generated gas at the moment of bursting tends to shatter the vessel into small pieces. The conversion to gas results from heat stored the liquid after surpassing its atmospheric boiling point; but the temperature at which the frangible vessel bursts, however, is not greatly above the boiling point of any liquid which can conveniently be employed and so, the amount of heat available to cause the generation of gas is small and the shattering action is, in consequence, also small. Further, prior to the date of this invention, it hasbeen proposed to employ a relatively non-volatile liquid and to enclose a small volume of air, or other sparingly soluble gas, in the trangible vessel with the liquid with the object that when heat makes the liquid fill the vessel,

this gas will be torced'into solution, but when the vessel bursts, the sudden expansion of 5, 1926. Serial No. 90,703. i

the said air, or other gas, contained in the vessel wlll cause it to shatter into small pieces. flu a the force, however, which can be exerted by the expansion of the relatively small volume of air, or other gas, contained in the vessel 1n this manner, is small. lhus, with the var1 ous methods proposed, prior to the date of .this invention, the amount of energy available to cause the effective shattering of the frangible vessel has been relatively small and consequently the vessel has had to be made with some degree of brittleness and consequently with some degree of unreliability, for the reason that in the absence of some degree of brittleness, the shattering force was not always su'fiicient to break the vessel into small pieces and some large pieces were left interfering with the proper opening of the sprinkler.

The principal object of this invention is to provide a frangible vessel with a filling which is capable of setting tree a far greater amount of energy when the vessel bursts than has hitherto been possible and so permit the material of which the vessel is made to be fully annealed and in this manner gain the great benefit of a stronger, tougher and generally more reliable frangible vessel than has hitherto been possible.

In the accompanying drawing Fig. 1 is a side elevation of the usual sprayer fitting showing the frangible vessel mounted therein. I

Fig. 2 is a vertical sectional view of the fitting and vessel.

Referring to the sprinkler comprises cap L) resting on the the hollow cone d.

fitting. a

My invent-ion comprises a trangiblevessel for an automatic sprinkler or fire extinguisher having therein. as its filling material drawing in detail the bulb 0 and supported by e is the usual sprayer a liquid which is highly compressible and has a high degree of thermal expansion. 7

My invention further comprises a trangible vessel for an automatic sprinkler or fire extinguisher having therein as its filling ma terial dimethylketone, dimethylketol, ketoa valve a carried by a r propane methylacetyl, pyroacetic ether, propanone or acetone or a mixture thereof.

These are organic chemical compounds, all

as it happens being aliphatic compounds, acetone being a liquid of the class of saturated ket-ones, and the others respectively ketone alcohols (ketols), acetals and esters. Any liquid which meets the requirements stated may be used.

The characteristic requirement is that there be a relatively high ratio of the coefficient of compression of the contained liquid to the coeflicient of extension of the material comprising the bulb walls; i. e., that the liquid has a capability of being com )ressed into a volume smaller than the volume which it naturally tends to occupy at the instant temperature, which capability exceeds the capability of the wells to be stretched or di torted by the pressure which the liquid applies to them; and this stretching pressure results fromithe Walls havinga co-efiicient of .thermal expansion lower than the co-efiicient of thermal ex pansion of the liquid which they confine. The inability of the liquid to get the space, which it tends to occupy at the higher temperature, puts it into a state of compression. This state of compression increases in intensity, with rise of temperature, until its net expansive pressure is sufficient to break the vessel wall.

The action is thus seen to be independent of the volatility or boiling point of the liquid, and independent of the presence of a gas with the liquid within the vessel. The action is rather a building up and storage, in the liquid, of energy in potential form which becomes kinetic when the wall first gives way, and makes it burst with shattering force and effect.

The action as a whole may be likened to an increasing attempt of a spring to expand against an element which re. ists the spring p to a certain point, and then breaks suddenly. The stronger the member that resists the spring, the greater will the spring tension become before the fracture occurs. According to the material used for the walls of the bulb and its heat treatment for strength and for guarding against brittleness, the relation between the ability of the walls to resist, andthe ability of the elastic liquid to store potential energy in itself before the resistance yields. and the temperature of yielding, may be made according to design.

The liquids before mentioned are highly compressible so that when compressed, due to the heating of the frangible vessel, they store up a very considerable amount of potential energy, ously expended when the vessel bursts. Further, the said liquids have a very high thermal expansion which compensates for the great compressibility previously referred to, so that the temperature of bursting of a which is almost instantane frangible vessel filled with the liquid may be made as low as is required in practice and, if desired, below the boiling point of the liquid. The liquids before specified are equally effective whether the frangible vessel does or does not include air or other gas.

' The vessel 0 is a sealed bulb containing the liquid herein described. It cracks when rise of temperature causes the expansive force of that liquid to exceed the strength of the walls; and thereupon the resistance of the walls is instantly greatly reduced, and the energy stored in the liquid which has been unable to spread them before the cracking occurred becomes suddenly able and expends itself with shattering effect so that no fragment of the walls remains in place. These walls, as already known, maybe of glass, fused. transparent quartz or other suitable material. Upon the shattering of the vessel its function as a strut ceases and the water within the sys tem is released through the opening left by the valve plug a, through which a jet of water issues striking the usual deflector c. The essential action of the frangible vessel being that it bursts when the temperature rises to a sufficient extent, it will be understood that the invention may be applied in any place where such vessels may be used, that is in any arrangement of members where a sired to occur at a predeterminined temperature. The methods of manufacture and of predetermining the temperature for bursting are well known, and can be practiced (without it being necessary to determine or measure the actual stresses involved) by a series of trials and approximations in preliminary experimental manufacture.

I claim 1. An automatic sprinkler comprising, as a means for normally holding the sprinkler closed, a frangible vessel containing a highly compressible gas-free liquid whose boiling point is higher than the intended operating temperature of the sprinkler.

2. An automatic sprinkler comprising, as a means for normally holding the sprinkler closed, a frangible vessel which at'normal temperatures is near'y filled with a gas-free liquid which is highly compressible, volatile and has a coefficient of thermal expansion greater than the coefficient of expansion of the vessel, and has a boiling point higher than the intended operating temperature of the sprinkler.

8. An article of manufacture consisting of a frangible vessel containing a highly compressible gas-free liquid whose boiling point is higher than the intended operating temperature of the sprinkler.

In testimony whereof I have signed my name to this specification.

JOHN TAYLOR.

release is de-

Images