US2391616A

US2391616A - Fog producing device

Info

Publication number: US2391616A
Application number: US507068A
Authority: US
Inventors: Herbert W Causer
Original assignee: Factory Mutual Research Corp
Current assignee: Factory Mutual Research Corp
Priority date: 1943-10-21
Filing date: 1943-10-21
Publication date: 1945-12-25
Anticipated expiration: 1962-12-25

Description

Dec. 25, 1945. w, CAUSER 2,391,616

FOG PRODUCING DEVICE Filed Oct. 21, 1943 MWYW Patented Dec. 25,1945

. FOG PRODUCING DEVICE Herbert W. Causer.

Factory Mutual Weymouth, Mass., asslgnor to Research Corporation, Boston,

Mass, a corporation of Massachusetts Application October 21, 1943, Serial No. 507,068

7 Claims.

This invention relates to a device for producing a fog of water particles or other material for use in extinguishing fires or as a screen or for other purposes, in contradistinction to an ordinary sprinkler nozzle which merely distributes water in relatively large globules over a wide area. The invention is particularly useful in extinguishing fires in vats or tanks of kerosene, fuel oil, rubber cement, lacquer and other inflammable liquids, which are diflicult to extinguish but which can be smothered by replacing the surrounding air with a fog of material incapable of supporting combustion. For example the devices of the present invention may be used to advantage in lieu of the spray nozzles disclosed in Patent 2,283,775 of Norman J. Thompson.

Objects of the invention are to produce a device of the character referred to which is'simple and economical to manufacture, which is reliable and eificient in use, which does not require excessively high pressure, which does not clog so easily as the old spray nozzles, which affords practically uniform distribution of fog throughout the cross-sectional area of the delivered stream, which permits the stream to be confined to a comparatively small cross-sectional area, and which is generally superior to the spray nozzles of the prior art.

The device of the present invention comprises a flaring bafile which is preferably conical, that is which has an outer surface approximating that of a cone, the baflle having slots extendin from its larger end toward its smaller end together with openings between the bottoms of the slots and the smaller end, so that when the smaller end of the bafile is held in line with a jet of water or the like, the jet is subdivided into smaller jets which pass through the slots and openings and then impinge on each other to form a fog the boundary of which is substantially defined by water deflected along the outer surface of the baffle in the shape of a cone. Preferably the walls of the slots lie substantially in planes which contain the axis of the bafile and the axes of the aforesaid openings are approximately parallel to the same axis, whereby the water passes through the slots and openings with less resistance and less deflection. Somewhat better results are obtained by locating the openings opposite the bottoms of certain of the slots so that each opening and adjacent slot are disopsed in the same axial plane. In the preferred embodiment the slots have approximately uniform width from end to end, in which case the fingers between the slots are keystone shaped. In order to confine the fog to a well-defined cone and to cause the fog to flow as a directed stream, the flare of the bafile should be less than approximately a right-angle, that is the angle subtended by opposite sides of the baffle should not greatly exceed The slots may be more or less elongate but opposite slots together preferably span at least approximately one-third the largest diameter of the bafiie. That is looking at the end of the baffle along its axis the apparent lengths of opposite slots added together are at least approximately equal to onethird the diameter of the baffle at the larger end. By making the baffle hollow thesubdivided jets passing through the slots and openings respectively impinge upon each other Within the baffle, so that the interior of the conical baffle constitutes an atomizing chamber.

In a more specific aspect the invention involves a combination of the aforesaid baflle with a nozzle.

directed toward the smaller end of the baflie and means to join the nozzle and the bafiie in predetermined spaced relationship so that the jet issuing from the nozzle is distributed approximatelyuniformly around the outer periphery of the bafiie. Preferably the means which join the nozzle and bafile is shaped to form the apex of the cone, the slotted part of the baffle comprising a truncated cone having its base seated against the aforesaid apex.

For the purpose of illustration a typical embodiment is shown in the accompanying drawing in which Fig. l is a full-sized side view of a typical embodiment, with a part broken away;

Fig. 2 is an enlarged end view;

Fig. 3 is a sectional view on line 3-4 of Fig. 2; but on the same scale as Fig. 1; and

Fig. 4 is a sectional view on line 3-4 of Fig. 2 of the bafile.

The particular embodiment of the invention chosen for the purpose of illustration comprises a nozzle I having a. reduced outlet 2 and a threaded end 3 adapted to be screwed into a pipe coupling, in combination with abafile comprising a hollow truncated cone 4. The cone is joined to the nozzle by means of two arms 6 which meet in a. tapered head 1 which constitutes the apex of the bafile. The end 8 of the truncated cone seats against the bottom of the apex 1 and is secured in position by brazing. In the illustration the nozzle is closed by a cap l2 held in place by two struts through opening I I, and a fusible link M in wellknown manner, but these parts are not essential to the present invention.

IS, an adjusting screw ll extending,

The truncated cone is provided with slots I6 extending from the larger end towards the smaller end and also-with circular openings I'I. The slots and openings should have sharp edges on top to permit the water to enter with less turbulence and therefore in greater quantity.

While the dimensions of the parts may be varied to some extent, excellent results have been obtained with those shown in the drawing which are approximately as follows: length of truncated cone-18 mm., length of apexl2 mm., making a total length of the conical baifie 30 mm.; the maximum diameter of the truncated cone-30 mm.; the length of the slots measured along the outer surface of the truncated conemm.; the width of the slots-2 mm.; the width of the fingers between the slots, measured near the bottoms of the slots (that is the closed ends of the slots)-2 mm.; the diameter of the outlet 26 mm.; the distance from the outlet 2 to the apex of the bathemm.; and the diameter of the openings "-3 mm. As shown in the drawing the flare of the truncated cone is approximately In installations where these devices are mounted over a tank or vat they are preferably distributed around the periphery of the tank or vat as disclosed in the aforesaid patent, about three feet apart and about six feet above the level of the liquid in the tank or vat. The subdivided jets which pass through the slots impinge upon each other and upon the jets flowing through the openings ll, whereby the liquid is broken up into a fog which, while very finely divided, continues to flow in the same general direction to form a cone which isentirely filled with fog of approximately uniform distribution.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. A fog device for use with a water jet to produce a conical stream of fog, comprising a flaring baffle having a plurality of radial fingers with slots therebetween of approximately uniform width extending from its larger end toward its smaller end and openings between the bottoms of the slots and said smaller end, said fingers extending away from said smaller end and throughout their extent having their center lines divergent relative to one another.

2. A fog device for use with a water jet to produce a conical stream of fog, comprising a flaring slots therebetween of approximately uniform.

width extending from its larger end toward its smaller end and openings between the bottoms of the slots and said smaller end, opposite slots together spanning at least approximately onethird the largest diameter of the bailie, said fingers extending away from said smaller end and throughout their extent having their center lines divergent relative to one another.

4. A fog producing device according to claim 1 further characterized in that the conical bailie is hollow to form an atomizing chamber in which the subdivided jets passing through the slots and openings respectively impinge upon each other.

5. A fog producing device according to claim 1. further characterized by a nozzle directed toward the smaller end of the baflle and means to join the nozzle and bafile in predetermined spaced relationship, said means being shaped to form the apex of the conical baflle.

6. A fog producing device according to claim 1 further characterized by a nozzle directed toward the smaller end of the bafile and means to join the nozzle and baille in predetermined spaced relationship, said means being shaped to form the apex of the conical baffle and the baflie comprising a truncated cone having its base seated against said apex. p

7. A fog device for use with a water jet to produce a conical stream of fog, comprising a flaring baffle having a plurality of radial fingers with slots therebetween of approximately uniform width extending from its larger end toward its smaller end and openings between the bottoms of the slots and said smaller end, said fingers extending away from said smaller end and throughout their extent having their center lines divergent relative to one another, and the walls of said openings being parallel with the axis of the water jet and the entrant edges of the openings being sharp.

HERBERT W.'CAUSER.