US2364199A - Apparatus for producing artificial fog or smoke - Google Patents

Description

Dec. 5, 1944. T. s. DERR 2,364,199

APPARATUS FOR PRODUCING ARTIFICIAL FOG 0R SMOKE Filed Jan. 18, 1943 Patented Dec. 5, 1944 APPARATUS FOR PRODUCING ARTIFICIAL FOG OR SMOKE Thomas S. Derr, Newton, Mass.,

American Steam Automobile Company,

assignor to West Newton, -Mass., acorporation of Massachusetts Application January 18, 1943, Serial No. 472,725

3 Claims.

This invention relates to the production of an artificial fog or smoke for use as a screen or any other purpose, and the principal objects are to provide a method of and means for producing a fog or smoke rapidly, extensively and at a relatlvely low cost, without risk of fire or explosion and with material which is inexpensive and readily available and which is non-injurious to man and equipment, to start the production of a fog or smoke on short notice, and to produce a fog or smoke of any desired color and quickly to change the color thereof.

Further objects will be apparent from a consideration of the following description and accompanying drawing, wherein the figure is a longitudinal section through what is now considered a preferred form of the apparatus.

According to the present invention the fog or smoke-producing apparatus comprises a series of interconnected nozzles or the like conduits arranged so that each successively discharges into the next succeeding nozzle which is of sufliciently greater size or cross-sectional area to create a zone of reduced pressure separated from the body of the main jet by a zone of turbulence; and each nozzle after the first one is provided with an inlet opening arranged to communicate with the zone of reduced pressure so as to provide an aspirator effect. One or more of the inlet openings may be connected with a supply reservoir or hopper of the material to be dispersed, and one or more of the other inlet openings may be connected with a suitable source of a gaseous diluent such as air, hot flue gases, or the like.

The material to be dispersed may comprise either a high boiling point fluid or a finely divided solid, such, for example, as clay, depending upon whether a fog or smoke is to be produced, the desired effects. etc. Clay and the like naturally occurring mineral substances are preferred in that such material is readily available, inexpensive, non-injurious and capable of being easily reduced to a flne state of subdivision. In any case a gaseous fluid such as compressed air or steam, preferably superheated, is discharged through the first nozzle so as not only to create a zone of decreased pressure which aspirates either the gaseous diluent or the material to be dispersed through the inlet opening of the second nozzle, but also sets up a zone of turbulence eflective to break up or disintegrate the aspirated material and entrain it into the main jet which travels through the second nozzle at a relatively high velocity. The same performance is repeated when the jet of the second nozzle discharges into the third nozzle and so on until the last of the series of nozzles discharges into the atmosphere.

The arrangement of the inlet openings for the diluent gases and the material to be dispersed may be varied and will depend upon the character of the material to be dispersed, the particular type of gas or gaseous fluid discharged by the first nozzle and the diluent gas or gasesadmitted to the other nozzles, and various other factors which will be recognized by those skilled in the art. Although the diluent gas may be aspirated as above noted, other inlets may be provided through which diluent gas may be introduced either under a pressure greater than that within the nozzle provided with such inlets, or by blowing the gas in at a suitable velocity. If desired, a plurality of supply hoppers, each containing a different colored dispersible material, may be connected to one or more of the inlet openings so that any desired color effects may be produced and valves or the like control means may be provided for each inlet opening so that the density of the smoke or fog may be adjusted or varied as desired.

The embodiment herein shown for the purpose of illustration comprises a series of interconnected axially aligned nozzles I, 2, 3 and 4 arranged so that nozzle l discharges into the adjacent end of nozzle 2, the said adjacent end of said nozzle 2 being of greater cross-sectional area than the discharge end of nozzle l; and nozzle 2 likewise discharges into the nozzle 3 which is of greater cross-sectional area than nozzle 2, etc. Although the dimensional relationship of the nozzles may vary, satisfactory results have been obtained using a nozzle I having a bore of the order of /4" and flaring to about a nozzle 2 having a bore of the order of 1"; a nozzle 3 having a bore of the order of 1 /2"; and a nozzle 4 having a bore of the order of 2" which may or may not flare outwardly. In any case the size of the discharge end of nozzles I to 3 should be sufficiently smaller with respect to the inlet ends of nozzles 2 to.4, respectively, so that a jet, indicated by the straight arrows'5, creates a zone of reduced pressure, indicated by stippling 6, which is separated from the main jet 5 by a zone of turbulence, indicated by the curved arrows I.

The nozzles 2, 3 and 4 are provided with inlet openings H], II and I2, respectively, each communicating with a zone 5 of reduced pressure, and the inlets are selectively connected by suitable duets with a source of the material to be dispersed and a diluent gas. Where, for example. the nozzle I is connected with a-supply or superheated steam, for example under a pressure of the order of 250 pounds per square inch, and

hot flue gases are to be used as a diluent, the inlets lll and I! are connected by ducts l4 and II with a supplyof flue gas and the inlet II is connected to a supply duct it formed with a funnel-like end' I! which receives the conical end I! or a supply hopper 20, the walls or the ends l1 and! being spaced to provide a gap is so arranged as to provide an aspirator effect. If desired suitable valves 2|, 22, 23 and 24 may be provided to control the flow through the nozzle I and inlets I0, H and I2, respectively.

In order to operate the apparatus to produce an artificial fog or smoke the hopper 20 is first supplied with a dispersible solid material of the 'desired color, such for example as clay or the like material, and with the valves 22 to 24 properly adjusted, the valve 2| may then be opened to discharge a jet 5 of superheated steam or other gaseous fluid into the nozzle 2, thereby creating a zone 6 of reduced pressure and a. zone I of turbulence. The zone of reduced pressure is effective to draw in through the inlet l hot flue gases, or other diluent, which are entrained with the main jet 5.

Under some conditions the diluent gas entering through opening l0 serves also to increase the capacity or efliciency of the apparatus by enabling a fixed amount of high pressure gaseous fluid to disperse more material than would be feasible if the jet of high pressure gaseous fluid acted directly on the material; in other words, the diluent gas entering through opening l0, under some conditions, makes possible an increase in capacity to disperse material, over what would be the case if the jet discharged from nozzle I acted directly on the material without the benefit of the diluent gas.

The jet travels through the nozzle 2 and discharges into the nozzle 3 and a similar action takes place. However, at this stage the jet aspirates the material to be dispersed through opening II and the zone of turbulence 1 is efiective to break up or pulverize this material so that as it is entrained by the main jet 5 it becomes entirely or almost entirely dispersed therein. As the material in the hopper 20 is drawn through the conduit l6, air is also drawn in through thegap I 9 which not only helps to regulate the flow of material through duct IE, but also tends to prevent clogging and thus, tends to efiect a more uniform introduction of the materialinto the nozzle 3 s As the jet 5 and its entrained material is discharged into the nozzle 4, more hot flue gases, or other suitable diluent, are aspirated through the opening l2 and these hot gases, or other suitable diluent, not only act to reduce or prevent condensation of the steam upon its emergence into the atmosphere (it steam is used), but also serve to create a greater degree of turbulence within the nozzle 4 than would otherwise occur, and hence are effective to improve the quality of the fog or smoke in that the particles of dispersed material are more thoroughly broken up and more uniformly distributed throughout the moving mass of gas. Finally the jet 5 is discharged from the end of nozzle 4 into the atmosphere to form a smoke cloud, the density and volume of which may be varied by proper adjustment of the valves 2| to 24 and the color of which may be varied or changed by introducing an appropriately colored material through the duct "5 into nozzle 3,

With the aforesaid sizes of nozzles and a steam pressure of the order of 250 pounds per square inch and a steam temperature of 600 F. to 700 F., the steam flow being of the order of eight pounds per minute, this apparatus will disperse a fine powdered clay such as bentonite at the rate of ten to fifteen pounds per minute; and on a, relatively calm day the apparatus will generate fog at a sufliciently rapid rate to obscure one-half acre to one acre per minute.

While I have shown and described one desirable embodiment of the invention, it is to be understood that this disclosure is for the purpose of illustration and various changes and modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. Apparatus for producing an artificial fog or smoke comprising a series of at least three interconnected nozzles, the second, and third nozzles being of greater cross-sectional area respectively than the first and second nozzles of the series so that a Jet of gaseous fluid discharging from one nozzle into the next nozzle creates a zone of decreased pressure separated from the main jet by a zone of turbulence, the second, and" third nozzles having inlets communicating with the zones of decreased pressure, means for introducing a dispersible .material through one of the inlets, and means for introducing gaseous diluent through another of said inlets.

2. Apparatus for producing artificial fog or smoke comprising a series of interconnected nozzles arranged so that one discharges into the next of the series, each nozzle receiving the jet discharged from the preceding nozzle being of greater cross-sectional area so that upon the discharge of the jet there is created a zone of decreased pressure separated from the main jet by a zone of turbulence, each of the jet-receiving nozzles being provided with an inlet communicating with the zone of decreased pressure, and supply ducts connected with said inlets for selectively introducing dispersible material and a gaseous diluent into the zones of decreased pressure.

3. Apparatus for producing artificial fog or smoke comprising a series of interconnected nozzles arranged so that one discharges into the next of the series, each nozzle receiving the jet discharged from the preceding nozzle being of greater cross-sectional area so that upon the discharge of the jet there is created a zone of decreased pressure separated from the main jet by a zone of turbulence, each of the jet-receiving nozzles being provided with an inlet communicating with the zone of decreased pressure, a supply hopper for receiving dispersible material connected to one of said inlets, and a duct for introducing gaseous diluent connected to another of saidinlets.

THOMAS S. DERR.

Images