US2765762A - Heat detector - Google Patents

Description

Oct. 9, 1956 J, A. CHAMBLISS HEAT DETECTOR Filed July 22, 1953 FIGURE 1;

INVENTOR.

HEAT DETECTOR John A. Chambliss, Lookout Mountain, Tenn.

Application July 22, 1953, Serial No. 359,565

1 Claim. (Cl. 115-405) My invention relates to a detector of heat that may ignite wood or similar combustible materials and more particularly to a fire detector to be placed in attics, cellars, closets, or at other points where no person may be present to detect, observe and warn of excessive heat that may cause accidental fire.

Various types of fire detectors have been used for the purpose of detecting excessive heat causing accidental fire. Such detectors are used to warn of secret fires, fires in infrequented places, or fire at night when occupants are asleep. In general, such detectors consist of electric detectors and spring actuated detectors. These detectors are more elaborate in construction, and while they are more sensitive to heat, the unit cost is about twice that of my invention; they are subject to tampering and corrosion and many depend on an electric current installation.

An object of my invention is to provide a fire detector and more particularly a fire detector which (a) is autonomous or self-contained, (b) detonates with a loud report from the heat of a fire, requires no maintenance, (d) is not easily tampered with, (e) has no moving parts, and (f) may be installed by the inexperienced.

The foregoing and other objects, features and advantages of this invention will be apparent from the following description and from the accompanying drawing of a preferred embodiment, it being understood that the detailed description and drawing are merely illustrative of the invention, which is defined in the claim.

In the drawings, Fig. 1 represents one embodiment of the invention in vertical position; and Fig. 2 represents a similar embodiment of the invention in horizontal position, with the jacket in cross-section.

Referring now to the drawings in more detail, a solid cylindrical metal jacket 1 is provided having reduced ends with circular apertures therethrough. Cylindrical cartridges 2 and 2a as shown in Fig. 2 are loosely jacketed within the container 1, and are of such dimensions that they will not pass through either of the apertures in the ends of the container 1. The cartridges 2 and 2a contain expansible fluids under pressure, to which, when applied, a predetermined amount of heat will explode the cartridges and create a suificient noise to alarm persons in the vicinity of the heat detector. Liquid CO2 has proven very effective as an explosive fluid within the cartridges. The metal used in the container 1 should be of high heat conductivity and of sufficient tensile strength to resist rupture or fragmentation upon explosion of the cartridges 2 and 2a. Alloys of steel or aluminum have proven very satisfactory.

It is highly important that the cartridges be loosely States Parent 0 2,765,762 Patented Oct. 9, 1956 jacketed within the container 1 in order that the explosion of the cartridges may be absorbed by the air cushion between the cartridges and the container, and also so that the noise created by the explosion will not be muted. The apertures in the ends of the container 1 allow the expanding gases and the noise to escape, as well as being adapted to receive the support hooks 3. By having apertures at both ends the tendency to produce jet action is reduced and provision is made for support hooks at both ends so that the container 1 may be easily suspended in horizontal position.

The containing jacket may be hung behind pictures on walls, placed behind books in bookshelves, or placed in furniture, as in the spring sections of chairs, couches, etc. If desired, it may have a support hook 3, attached thereto for hanging it from the ceiling of a cellar, closet, or other place where observation would not be objectionable. It may also be suspended from curtain rods, placed behind books, clocks, over furnaces, or near electric wires or in fuse and switch boxes, or in immediate roximity to other objects potentially dangerous from the standpoint of starting fires. It may be secured to wooden surfaces by a pipe strap to prevent easy removal and also be laid in attics or placed on beams, sills, among rafters, or in the studding of a building.

Since cylinders build up pressure from heating, the rupture is dangerously violent. A ruptured metal cylinder spreads, forming a sail, which the pressure violently projects and is hazardous. Thus it is unsuitable for use as a detector unless controlled by being jacketed.

Before wood which it is in immediate proximity to ignites and before the temperature rises to a point far less than that of the lowest flame, cylinders 2 and 2A will noisily explode, almost certainly at an interval. The noise of the detonations will warn a person in the immediate vicinity.

By my invention there is provided a fire detector which operates automatically to warn persons of the presence of a fire. The detector is thoroughly reliable in operation, and due to its low cost of manufacture can be used liberally in all constructions in which fire hazard exists.

I claim:

A heat detector comprising a solid cylindrical container of high heat-conductive metal, said container having tapered end portions terminating in circular apertures, a plurality of cylindrical cartridges containing fluid under pressure arranged loosely and end to end within the container, each cartridge end portion adjacent an aperture in the container having a spherical shape to prevent rupture of the cartridge opposite the container apertures, and the outside diameter of each of the cartridges being greater than the diameter of each aperture and less than the inside diameter of the cylindrical container, the spacing between said cartridges and said cylindrical container being suificient to provide a shock absorbing air cushion and to permit the rapid flow of expanding gases to both apertures.

References Cited in the file of this patent UNITED STATES PATENTS 2,059,113 Kalstrom Oct. 27, 1936 2,548,382 Lovelace Apr. 10, 1951 2,626,586 Mendes Jan. 27, 1953

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