US3388868A - Foam producing nozzle - Google Patents

Description

.June 18, 1968 w. R. WATSON E'r Al. 3,388,868

FOAM PRODUCING NOZZLE Filed Oct. 29, 1965 Inventors 'william RfWalSorL- .DonaldR-Ander'sorz .B m d-l/ Mmmraub" Ma Marne@ United States Patent Oflice Patented .lune i8, i9@

3,383,868 FOAM PRODUCING NOZZLE William R. Watson, Oak Lawn, and Donald R. Anderson, Oswego, lll., assignors to Nalco Chemical Company, Chicago, lll., a corporation of Delaware Filed Oct. 29, 1965, Ser. No. 505,705 8 Claims. (El. 239-427) ABSTRACT OF THE DISCLOSURE This invention is directed to a foam-producing nozzle comprising a series of continuous fluid-conducting zones. These zones comprise an aspirating zone, a mixing zone, a foam-forming zone and a foam-shaping zone. These zones are in sequential relationship t each other.

This invention relates to a nozzle useful in spraying liquids as foams.

Over the past several decades, numerous foam spraying nozzles have been used as a regular part of large scale fire-lighting procedures. These nozzles have been designed to produce foams by either the simple expedient of aerating water, by the introduction of chemical foaming agents and by the combination use of both aeration and foam producing chemicals. Various nozzles have produced useful effects but in many cases they are subject to limitations from a mechanical design standpoint and with respect to the type of spray pattern produced.

While foam producing nozzles have been used for many years in combating fires, they have not been utilized to any extent in the spraying of pesticides such as herbicides or insecticides. One example of where foam producing nozzles are of value is the application of herbicidal materials to railroad right-of-ways. They are particularly beneficial when spraying brush control chemicals, which application often requires spraying liquids for distances as great as 50-75 feet from the top of specially designed moving railway cars.

While high pressure nozzles have been utilized in applying herbicidally active chemicals along railroad rightof-ways7 on the shoulders of highways and along utility routes, such applications using conventional nozzles have one major deficiency. Conventional nozzles, when used to apply herbicidally active chemicals at high pressures, eg. in excess of 2() p.s.i., under certain conditions of windage, shape and height of the pattern, and the like, produce excessive amounts of mist or fog which can drift from the intended pattern. These undesirable mists transmit the herbicidally active chemicals to areas which frequently contain valuable vegetation such as agriculturaltural crops and ornamental plantings such as shrubbery and trees, thereby causing injury to these desirable plants.

To overcome the drift problem, it has been discovered that herbicidally active chemicals may be applied by means of a special foam producing nozzle which provides several advantages heretofore not achieved by conventional spraying techniques. The nozzles are also useful in providing a maximum quantity of fluid to a predetermined location thereby making them extremely valuable for fighting various types of fires.

The nozzles of the invention are capable of adaptation to produce a variety of spray patterns which are substantially drift free under most atmospheric conditions and which are capable of being simply modified to produce an applied fluid whose finished character from a standpoint of foam density and fluid Wetability is capable of giving optimum results under a wide variety of conditions.

One of the problems encountered in using some existing foam producing nozzles is that in cases 0f excessive fluid pressures these nozzles are frequently flooded This flooding phenomena is manifested by the fluid applied being discharged from the nozzle through air inlet ports which are oftentimes used in the construction of these nozzles. This flooding, when it ocurs, oftentimes creates a spray which wets the operator. Such operator wetting due to flooding is not dangerous in the case of spraying water, but when extremely toxic chemicals are released by flooding the condition is serious and should be avoided.

lt therefore becomes an object of the invention to provide an improved foam forming nozzle capable of use in the application of herbicidally active chemicals.

Another object of the invention is to provide an improved re-figbting and prevention nozzle.

Still another object of the invention is to provide a foam formin7 nozzle capable of being readily adapted for use in a variety of applications, where it is desirable to apply fluids in the form of foams.

A further object of the invention is to provide a foam forming nozzle which is so designed as to prevent flooding conditions from occurring.

Yet another object of the invention is to provide a foam forming nozzle which is capable of producing a foam of substantially uniform particle size which is projected as a uniform, steady stream.

Other objects will appear hereinafter.

For a more comprehensive understanding of the invention, reference may be had to the drawings of which:

FlG. l is a horizontal plan view broken away in part to show the detailed construction of a typical nozzle of the invention.

FIG. 2 is a sectional view taken across lines 2 2 of FIG. 1.

FIG. 3 is a horizontal plan view of the foraminous members used in the foam forming zone of the nozzle.

FIG. 4 is a horizontal plan view of the nozzle of the invention used in conjunction with an aspirator which allows chemicals to be fed into fluids being introduced into the nozzles.

FlG. 5 is a plan view showing the end of the nozzle fitted with a stream-diverting attachment.

With specific reference to the drawings, there is shown in FIG. 1 a nozzle 1li having aninlet 12 and an outlet i4. The sequential arrangements of the components form several zones or functional areas which are designated generally by the letters A, B, C and D respectively with the end of one zone being the begining of the next.

Zone A, which may -be considered as an aspirating zone, is composed of duct i6 which may be in the form of a conventional threaded pipe nipple for allowing the nozzle to lbe connected to a source of fluid (not shown). Theinlet 12 of the nozzle which forms the inlet of theduct 16 contains an end-plate 18 which is fitted in sealing relationship. The end-pl-ate fitted to lthe duct is shown to best advantage in FIG. 2. The end-plate is provided with a plurality of spaced apartcircular openings 20 into which are flange fittedfluid conducting tubes 22. The endplate 1S acts as a spacer and as a mounting support for fluid conducting tubes, that may be cemented into the end-plate by means of an epoxy resin or similar adhesive.

The fluid conductingtubes 22 extend horizontally in spaced apart relationship throughout substantially the length ofduct 16 and terminate near screen 24. The tubes may touch the screen Zd although they may be slightly above the screen with good operational results being achieved in either case. Theduct 16 has positioned about its circumference near inlet 12 a plurality of air-inlet 3openings 26. The outlet end 27 ofduct 16 is fitted with abushing 28 which connects the duct to au outer housing such aspipe 30. Theoutlet 32 Iis also tted with apacking collar 34 which, for purposes of sealing, is additionally fitted with an O-ring 36.

Withintluid conductor 30 is a sleeve 38. Sleeve 38 has mounted on its one end screen 24 and on itsother end screen 44. Sleeve 38 therefore acts as a spacer forscreens 24 and 44. Adjacent to screen 44 are twoadditional spacers 46 and 48 which hold in spaced apart relationship screens Si) and 52. This arrangement of spacers and screens is shown in detail in FIG. 3.

Engagingscreen 52 againstspacer 48 isbarrel 54 which fits in sliding relationship with respect to thefluid conductor 30. Thebarrel 54 is prevented from moving with respect to thescreens 44, Sit and 52 by setscrews 56.

Theend 14 of thenozzle 10 has itsouter edge 58 back beveled to provide a smooth, sharp line of release for the emerging foam and thereby provide a substantially distortion free uniform solid foam stream.

As indicated, the nozzle is constructed to form a series of zones in which occur a number of sequential functional steps with respect to the overall operational etliciency in the nozzle. The zone areas are generally indicated as Zones A through D inclusive. These letter designations are not intended to be precise but merely indicate general regions within the nozzle.

Zone A may be considered as an aspirating zone with Zone B being a mixing zone. ZonesC and D, respective 1y, are foam forming and foam shaping zones.

Illustrative of the operation of the nozzle would be the injection of water intoinlet 12 of thenozzle 10. This water is conveyed by fluid conductingtubes 22 to screen 24. In an area around screen 24 a strong aspiration effect is achieve. The air is drawn through air-inlet openings 26.

An important concept of the invention is that aeration which occurs near screen 24 is substantially uniform and thorough. The air mixes throughout the entire crosssection of the lluid. This elfect is achieved since the air which enters the air-inlet openings 26 is transported uniformly throughoutduct 16.

Due to the uniformity of aspiration, better foaming elects at greater pressures can be achieved. The aspiration etfect which was just described occurs in Zone A. Concurrently with the water being aspirated, rapid mixing of the two media occurs in mixing Zone B.

With the aeration and mixing having taken place, the water then moves againstscreens 44, S and 52 which comprise the beginning of foam forming Zone C. After being formed in Zone C the foamed tluid is then passed into foam shaping Zone D where it is ejected fromend 14 ofnozzle 10 in a substantially distortion free iluid dispersion pattern.

Another important advance in the art made by this invention is the concept of the foam forming zone which containsfoam forming screens 44, 50 and 52. It is possible to create foams of Varying uniformity and cohesiveness by changing the size, arrangement and number of the screens. Experimental evidence indicates that when large mesh screens are used, a coarse structured foam is formed. Therefore, a single large mesh screen will provide a coarse structured foam. Fine mesh screens produce tine structured foams. When a number of screens are used, a greater uniformity of the Afoam and iinished spray is achieved as well as the effect of producing foam particles having the desired size.

By providing a variety of different mesh size screens, it is possible to quickly determine optimum conditions for a particular application. The foam forming screens are particularly elective in producing useful foams when the liquids passing through the nozzle have been treated with suitable toam forming and foam stabilizing chemicals.

Experimentation has shown that the back-beveledouter edge 58 ofoutlet 14 is important from the standpoint of creating a uniform fluid applicational pattern. Without the back beveling it was found that stream distortion occurred.

When the nozzles of the invention are used as firefighting nozzles, it is sometimes advantageous that they be equipped with means for allowing the introduction of foam forming and fire suppressing chemicals. One simple method for adapting the nozzles for such purpose is shown in FIG. 4. In thisembodiment inlet 12 is tted with an eductor 6i) which has an inlet 62 and a suction port 64. This port is connected to a suitable source of foam producing chemicals (not shown). It will be obvious to those skilled in the art that instead of using eductor 60` other means for introducing chemicals such as metering pumps may be used.

When the nozzles are used for applying herbicidally active chemicals, theoutlet 14 of thenozzle 10 may be fitted with an adjustable duck-billed shaper which will produce a fan-shaped spray where such a spray pattern is desired. The duck-billed spray shaper axed to the end of the nozzle is shown in FIG. 5.

The duck-billed spray shaper is composed of alternately opposedlips 66 and 63. The leadingedges 70 are of greater linear dimension than back edges 72. The lips are titled withsides 74 to form inverted scoops. Aixed near back edges 72 are mountinglugs 76 and 78 which are pivotally mounted to the end of the nozzle by means ofrivets 80. Positioned behind the duck-billed shaper isslidable collar 82 which may be locked by means ofwing nut 84, onto the end of the nozzle.

By pivoting the lips of the duck-billed shaper and forcing thecollar 82 thereagainst it, it is possible to lock the shaper into any desired position. This shaper allows a drift-free foam to be applied by the nozzle in a fan-shaped pattern which is valuable in applying herbicidal materials.

Instead of using the duck-billed shaper in FIG. 5, other pattern shaping devices may be used. For instance, if a conical spray is desired, a suitable conical shaper may be placed inside theend 54 of thenozzle 10. A variety of spray patterns can be achieved by using other types of known spraying pattern shapers.

Comparative testing of the nozzles described against other so-called foam forming nozzles has shown them under conditions of high windage and humidity to reduce spray drift as much as L90% based on visual inspection.

The nozzles may be constructed of a variety of materials such as standard iron, steel or plastic piping. When .corrosive liquids are to be applied through the nozzles such materials of construction as stainless steel and plastics are preferred so as to minimize the destructive :action of these chemicals on the nozzles.

We claim:

1. A nozzle useful for applying uids in the form of a foam, which is composed of a plurality of uid conducting continuous zones, said zones being in sequential relationship to each other and comprising:

(I) An aspirating zone, said aspirating zone being further characterized as having:

(A) an inlet and a foraminous outlet,

(B) a plurality of lluid conductors extending substantially throughout said aspirating zone, and

(C) air conducting means for conveying air to a point near said foraminous outlet, comprising a duct substantially `enclosing the fluid conductors, said duct having at least one inlet open to the atmosphere;

(II) A mixing zone, said mixing zone comprising a chamber having an inlet adapted to receive air and iluid from the aspirating zone and an outlet which comprises the inlet of (III) A foam forming zone, which comprises a lluid conducting chamber having positioned therein in the path of said uin a foraminous foam forming member and an outlet which comprises the iilet of the (1V) Foam shaping zone, said foam shaping zone comprising a uid conductor.

2. The nozzle of claim 1 where the foraminous foam forming member positioned in the foam forming zone comprises at least two screens positioned in perpendicular relationship to the fluid ow through said foam forming zone.

3. The nozzle of claim Z Where the outlet of the foam shaping zone is substantially circular in cross-section and is back-beveled.

4. The nozzle of claim 2 where the outlet of the foam shaping zone is adjustable to provide variance in the type of fluid dispersion pattern.

5. The nozzle of claim 4 where the outlet is an adjustable duck-billed shaper capable of forming a substantially fan-shaped pattern.

6. The nozzle of claim 1 where the inlet of the aspirating zone is associated with mechanical means adapted to introduce foam forming chemicals into the nozzle.

7. The nozzle of claim 6 where the mechanical means adapted for the introduction of foam forming chemicals is an aspirator.

8. A nozzle useful for the dispersion of aqueous iluids in the form of a foam which comprises a substantially tubular conductor having an inlet and outlet, said inlet being composed of a tubular duct having near its entrance end a plurality of air-inlet openings and a foraminous outlet, a support located Within the entrance of the duct to hold in spaced apart relationship a plurality of tubular fluid conductors whose ends terminate near the end of the foraminous outlet of the tubular duct, and a pipe positioned at the foraminous outlet of the duct which has contained therein foam forming screens which are in substantially spaced apart relationship to each other with the end of said pipe being the outlet of said nozzle.

References Cited UNITED STATES PATENTS 2,408,588 10/1946 Watts Z39-553.5 X 2,609,240 9/1952 Faulkner et al. Z39-590.5 X 3,094,171 6/1963 Gagliardo 169-15 3,138,332 6/1964 Hinderer 239-427 ALLEN N. KNOWLES, Primary Examiner.

M. HENSON WOOD, JR., Examiner.

H. NAT'TER, Assistant Examiner.

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