US2317836A - Safety apparatus - Google Patents

Description

April 27 1943- L.. L WEAVER 2,317,836

SAFETY APPARATUS Filed May 7, 1941 FIG. 4A

A TTOPNEV` Patented Apr. 27, 1943 IUNITED sTATEs PATENT OFFICE I samllms i I Leo L. Weaver, Cranford, N. J.; assignor .to

Western Electric Company, Incorporated, New York, N. Y., a corporation of New York ammunition May '1, 1941, semi 10.392.332

against explosively dangerous vapors. A

There are innumerable instances in industry where it is necessary to store in temporary or more or less permanent fashion materials which will produce or give off inflammably explosive gases or vapors, especially if abnormal/conditions become accidentally created in their immediate environment. Thusfor example, a great variety of mixtures comprising, alone or with other ingredients, a solid such as cellulose acetate softened or dissolved in an inflammable volatile liquid such as acetone, are used in many ways in various arts. In particular, in the art of manufacturing insulated electrical wire, a thickish solution, dispersion or paste of cellulose acetate inv acetone with other ingredients isused to coat wire, either bare orrhavlng a sheath of insulation thereon to which the cellulose acetate-acetone mixture is applied.

Such mixtures are ordinarily made up and held in some kind of storage tank or receptacle. The mixture may be made up in or'suppliaed to the tank in batches intermittently, as itis used up; or, in some cases, it may be made up continuously at the rat'e at which it is being used. In either case it is generally preferable to have a substantial pool of the mixture to draw from in order to ensure constancy of protection of ingredients in the mixture, and this pool'wiil be kept in a storage or supply tank or other container. Under normal atmospheric conditions, particularly of temperature, the evolution of vavpors from the material in the tank will be insuiilclent to create any hazard not to be controlled by ordnary means. However, lf abnormal conditions arise, e. g. an abrupt and considerable rise 1n temperature such as might be occasioned by a fire in the building or by the rupture of an adjacent steam line or otherwise, there may occur a relatively enormous evolution of vapor, even enough to burst the tank and to liberate the vapors into the outer air. Being easily infiammable and also capable of making violently explosive mixtures with air, such circumstances are obviously hazardous.

An object of the 4present invention is to provide means whereby sucn hazards may be greatly d mlnished and even substantially prevented, tne means being set in operation by the circumstances which tend to create .the hazard..

Wits the above and other objects in view the invention may he embodied, in connection with a receptacle to hold material tending to produce dangerous vapors and having a normally closed explosion relief aperture therein, in means to open the relief aperture and simultaneously to smother and dilute vapors issuing therefrom with a, non-inflammable explosion preventing gas, the said means being actuable by a device positioned Within the receptacle and set in ac-4 tion by the occurence therein of an abnormal condition. l

Other objects and features of the invention will appear from the following detailed description of one embodiment thereof taken in connection With the accompanying drawing in which the same reference numerals are applied to identical parts in the several gures, and in which Fig. 1 is a diagrammatic view in side elevation of an apparatus constructed in accordance with the invention;

Fig. 2 is a portion of Fig. 1 altered to show a modied form;4

Fig. 3 is another portion of Fig. 1 similarly altered for the same form; and

Fig. 4 is a view similar to Fig. 2 lof anothe modication.

In the embodiment ofthe invention shown inl containing a volatile, inflammable liquid as'one l of its ingredients, e. g. acetone, so that the material 2l tends to evolve gases or vapors inflammable and capable of forming explosive mixtures with air. Access may be had to the tank interior to supply or remove material through a suitable aperture in the top, as at 22, tightly closed ordinarily, as by the bolted lid 23. There is another aperture in the top at 24 with an upstanding collar 25 around it and formed'at the top with an -everted ange 26. A flat ring 21 of internal diameter somewhat larger than that of the col'- -lar 25 is secured upon the upper face of the flange increase of pressure arise within the tank, e. g.

because ofan accidental explosion therein.

A plurality (here four) of spacing members :19, each a vertically bored cylinder as shown ere, stands on the ring 21A and supports a ring 30 similar in shape to the ring 21, butpreferably of slightly smaller internal diameter. On. the

ring 30 rests a dat, horizontal sheet or diaphragm livery member 33, is supported on' the diaphragm4 y 3|, either directly, or as shown, with a sealing washer 34, of some suitable material such as ordinary rubber impregnatedlcloth packing.

A gas delivery nozzle 35\in the top of the trumpet 33 is connected by suitable piping to the delivery valve 3B oi' a compressed gas tank 31 filled with some gas under pressure, e. g. carbon dioxide, nitrogen or the like, which is noninlammable and tends to prevent or smother fire. The valve 36 is actuatable to open by a'lever 38 operable by suitable means such-as the weight 39 attached to the lever.

wire rope 48 secured to one horizontal arm 42 of a three-armed lever generally indicated at 4|. The weight 39 and cord 40 normally tend to turn the lever 4| clockwise to allow the weight to drop. This is prevented by a detent 45 caught against the upper end oi a vertically upstanding arm 43 of the lever 4|. The third arm 44 of the lever 4| is formed as a counterpoise weight tending to turn the lever 4| counterclockwise but insufficient to overcome the eiiect of theweight 39.

The detent 45 is formed on the outer end of one arm of a lever 46 urged clockwise by a spring 48 and held against clockwise motion either by the arm 43 of the `lever 4| or by a ilxed stop member 49. The lever 48 may be actuated to turn counterclockwise by a push rod 50 acting on the arm 41 of the lever.

The push rod 50 is secured to one end of a corrugated metal bellows 5| into the other end of which an actuating tube 52 is secured to communicate with the otherwise imperforatedly walled interior of the bellows. The tube 52 may preferably be contained within an outer coaxial shield tube 53, and enters the tank 20 at a point above the ordinary maximum level of the material therein. There the tube is secured to and communicates with the interior of a hollow metal bulb 54, here shown as contained in and supported by a guard cage 55 or heavy wire.

The bulb 54 is of thin walled but relatively rigid metal, preferably of a metal or metallic alloy, having relatively high heat conductivity and also not subject materially to corrosion by vapors from the material 2|. In the case or acetone vapors for example, sheet copper will be a suitable material for the bulb. The walls of the bulb are wholly impertorate except for the sealed in tube 52 and except for a breather hole. This breather hole is not shown on 'the drawing because it is merely pinhole through the bulb wall at any convenient location, too small to be shown. It plays no part in the actual operation of the invention, merely acting to prevent false operation of the apparatus by normal slow changes of atmospheric temperature or barometric pressure, by allowing air to seep slowly into or out of th bulb and thereby keep the gas pressure within the bulb and bellows equal to the atmospheric pressure outside. However, this breather is too small t0 allow these The lever is normally held in the valve closing position by a cord orpressures to equalize in case a sudden rise of temperature about the bulb effects a rapid rise u of pressure within if. e

In such a case. before the breather hole can relieve the excess pressure within the bulb, this pressure transmitted through the pipe 52 will expand the bellows 5|, drive the push rod 50 down on the lever arm 41 and lift the `detent 45 from its-engagement with the leverarm 43. The lever 4| will then rotate clockwise under the pull of the cord 40 and weight 39, allowing the weight 39 to turn the lever 38 to open the valve 36. The gas released by the valve passes through the connecting pipes and the nozzle 35 into the delivery trumpet 33, vbuilds up suillcient pressure f .sumably under some pressure from the abnormal.

heat in the vicinity of the bulb 54, are thus released and immediately so diluted with noninammable, smothering gas from the trumpet 33 that all danger of explosion or even of re from these vapors is averted.

Ordinarily the parts of the chain of apparatus from the bulb 54 to the valve lever 38 are s'o proportioned that the system will operate at a temperature about the bulb 54 just a little lower than is required-to expand the vapors in'the tank -20 enough to rupture the diaphragm 28 themselves.

Although for convenience in drawing the gas tank 31 and the mechanism from the bellows 5| to the tank valve 36 are shown in close juxtaposition to the storage tank 28, these will in actual practice be located at some distance from the storage tank, as suggested by the breaks shown in the interconnecting pipe lines, perhaps even in another room. Then should external nre menace danger from the storagetank too imminent to permit of waiting for the automatic actuation, the cord 40 may be released. from the lever -arm 42 by means of the knot or handle 56 on the upper end of the cord. To this end the lever arm 42 isA forked, the cord passes up through the fork, and the handle 58 rests on the legs of the fork. With the cord thus detached from the lever, the weight 38 is free to move the lever 38 to open the gas valve.

In the modified form disclosed in Figs. 2 and 3, the bulb 54 is replaced by a thermoelectric device |54 connected through wires |52 replacing the tube 52 to a solenoid |5| whose pullrod |50 actuates the lever arm 41. Both of the arrangements above described operate upon the occurence of an abnormally high purely pressure responsive device such as a metallic bellows 254 which will shorten under external gas pressure and thus move the rod 251 'to close an electrical switch 258 and thus actuate lthe solenoid of Fig. 3 upon the occurrence of an excessive pressure of predetermined amount within the container.

" While al1 the forms above tdescribed are adapted to provide a blast of non-inflammable gas tank 31 could-be replaced by -a source of vnon-inflammable liquid, especially if the material 2l and its vapors are soluble or miscible in the particular liquid employed. The nozzle 35 would then be formed as the case mightrequire,

to deliver the liquid as foam, spray or in a jetk according to its nature.

'I'he embodiments shown are illustrative and may be modied and departed from in various waysvwithout departing from the spirit and scope of the rinvention as pointed out in and limited only by the appended claims.

container.

2. A safety apparatus for a container for materials which may evolve vapors and which container is provided with a relief aperture and means to close the same, the said apparatus comprsing a nozzle opposed to the aperture and connected through a valve to a supply of non-inflammable uid, and means actuable :by the occurrence in the container of an abnormal condition to open the valve torelease fluid through the nozzle to open the aperture and to surround the same with the non-inammable fluid.

v3. A safety apparatus for a container for materials which may evolve vapors and which container is provided with a relief aperture and means to close the same, the said apparatus comprising a nozzle opposed to the aperture and connected through a valve to a supply of non-innammable fluid, and temperature responsive means actuable by the occurrence in the container of anl abnormal temperature to open the valve to re- 2,317,836 gas or vapor from the nozzle 35, if desired the apparatus comprising a nozzle opposed to the aperture and connected through a valve to a supply of non-inflammable fluid, and means actuable 4=by the occurence in the container of an abnormal condition to openthe valve to release fluid through the nozzle to rupture the diaphragm and to surround the aperture with uid.

6. A safety apparatus for afcontanerv for materials which may evolve vapors and which conlease fluid through the nozzle to open the -aperture and tov surround the same with the noniniiammable fluid.

4. A safety apparatus for a container for materials which may evolve vapors and which container is provided with a relief aperture. and means to close the same, the said apparatus comprising a nozzle opposed to the aperture and connected through a valve to a supply of noninammable fluid, and pressure responsive means actuable by the occurrence in the container of an abnormal pressure to open the valve torelease duid through the nozzle to open. the aperture and to surround the same with fluid.

5. A safety apparatus for a container for materials which may evolve vapors and which container is provided with a reliefaperture and a rupturable diaphragm to close the same, the said tainer is provided with a relief aperture and a rupturable diaphragm to close the same, the

said apparatus comprising a shatterable dlaphragm spaced from and opposed to the rupturable diaphragm, a fiuid ejection nozzle directed toward the shatterable diaphragm on the other side thereof from the rupturable diaphragm; means including a valve to supply non-infiammable uid .to the nozzle, and means `actuable by the occurrence in the container of an ab-. normal condition to open the valve to release fluid through the nozzle to shatter the shatterable diaphragm and project the lfragments thereof to rupture the rupturable diaphragm while the fluid also surrounds the aperture.

7. A safety apparatus for a container'for materials which may evolve vapors and which container is provided witha relief aperture and a rupturable diaphragm to close the same, the said lapparatus comprising a shatterable diaphragm spaced from and opposed to the rupturable diaphragm, a fluid ejection nozzle directed toward the shatterable diaphragm on the other side thereof from the rupturable diaphragm, means including a valve to supply non-infiammable fluid to the nozzle, and temperature rey sponsive means actua-ble by the occurrence in the container of an abnormal temperature to open the valve to release uid through the nozzle to shatter the shatterable diaphragm and project the fragments thereof -to rupture the rupturable diaphragm while the fluid also surrounds t aperture.

8. A safety apparatus for a container for materialswhich may evolve vapors and which container is provided with a relief aperture and a rupturable diaphragm to close the same, the said apparatus comprising a shatterable diaphragm l spaced from and opposed to the rupturable diaphragm, a`uid ejection nozzle directed toward LEO L. WEAVER.

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