US 3836076 A
A nozzle and method for generating a foamed liquid includes a nozzle body, a plurality of spaced orifices forming discrete jets of a liquid foam producing agent in an elongate passage in the nozzle body, and a solid surface defined in the body upon which the jets impinge. Gas inlet openings introduce gas into the passage and the gas and liquid foam producing agent are intimately mixed by deflection of the latter from the solid surface to produce foam in the passage.
Claims available in
Description (OCR text may contain errors)
United States Patent Conrad et al.
[ Sept. 17, 1974 I FOAM GENERATING NOZZLE  Inventors: Sherman E. Conrad; Dennis W.
Bintner, both of Des Moines, Iowa  Assignee: Delavan Manufacturing Company,
West Des Moines, Iowa  Filed: Oct. 10, 1972  Appl. No: 296,352
 U.S. Cl 239/8, 169/15, 239/428.5, 239/431, 239/432, 239/597  Int. Cl B05b 7/04, B05b 15/04  Field of Search 169/15; 239/8-10, 428.5, 431, 432, 597, 598
 References Cited UNITED STATES PATENTS 1,753,443 4/1930 Murray 239/597 2,127,883 8/1938 Norton 239/597 X 2,198,585 4/1940 Urquhart et al. 169/15 X 2,423,618 7/1947 Rotzer 169/15 X 2,492,037 12/1949 Freeman et al 169/15 X 2,761,516 9/1956 Vassilkovsky 169/15 2,765,856 l0/l956 Schultz 169/15 3,199,790 8/1965 Giesemann 169/15 X 3,563,461 2/1971 Cole et al. 239/9 3,604,509 9/1971 Sachnik 169/15 3,701,482 10/1972 Sachnik 169/15 FOREIGN PATENTS OR APPLICATIONS 221,878 6/1959 Australia 239/4285 1,166,068 10/1969 Great Britain 239/428.5 1,178,631 l/l970 Great Britain 239/597 Primary ExaminerRobert S. Ward, Jr. Attorney, Agent, or Firm-Molinare, Allegretti, Newitt & Witcoff [5 7 ABSTRACT 20 Claims, 5 Drawing Figures 1 FOAM GENERATING NOZZLE BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to foam generating nozzles and, more particularly, to a foam generating nozzle and method in which a liquid foaming agent impinges on a solid surface prior to the discharge of the foam from the nozzle.
Foaming of liquid solutions is presently receiving wide attention today in several fields. In the agricultural field, foam application is extremely attractive for the application of pesticides, including both herbicides and insecticides. The foaming of pesticides substantially reduces both ground or aerial drift and thereby also reduces or eliminates altogether undesirable damage to surrounding crops and vegetation. In addition, the foam application of pesticides reduces run-off which might otherwise result in environmental damage,
reduces evaporation, provide 5a ready visual indication of spray coverage and reduces the amount of active chemicals that must be applied per unit area. Foam application techniques are also enjoying wide attention in other agricultural fields including the protection of plants against climatic conditions such as frost, hybridizing, seeding and the like. In addition to agricultural uses, foaming has been widely used in other fields for several years including fire fighting and detergent cleaning operations in which foam is employed as the cleaning agent.
In general two different methods have been employed in the generation of such foams. In one method, a chemical foaming agent is added to the solution to be sprayed which upon discharge from the applicator chemically produces the desired foam. The second general method consists of introducing air into a liquid to form millions of bubbles which make up the foam. Such air can be introduced either by an air aspirating nozzle in which the foam is formed just before being discharged from the nozzle or by the use of specially constructed foam generators and pumps which take in air and blend it with a small amount of foamable liquid and this foam is then pumped through a hose to the point of application.
The present invention is directed to a foam generating nozzle and method in which air is introduced into a liquid foaming agent to generate the foam just before discharge from the nozzle. Such foam generating nozzles have taken several forms in. the past. In one form of foam generating nozzle, the liquid foam producing agent is jetted onto a mesh strainer. The liquid passing through the strainer mesh reduces the pressure in the nozzle body to cause air to be drawn through the mesh and mixed with the liquid to generate foam. Another form of foam generating nozzle in use today comprises a simple elongate nozzle body through which the liquid foam producing agent is jetted directly through the nozzle body without further contact with the nozzle. This jet of liquid foam producing agent reduces the pressure in the nozzle body to aspirate air into the body where it is mixed with the liquid to form the foam which is discharged from the nozzle.
In the present invention a foam generating nozzle and method of foaming produces a high quality foam having millions of tiny air bubbles interspersed in the foam. In the present invention at least one discrete jet of liquid foam producing agent is formed in the nozzle body and a solid impingement surface is loacted in the path of the jet such that the jet impinges upon the surface and is deflected from the surface. The deflected liquid foam producing agent is thereby intimately mixed with the air which has been drawn into the nozzle body to produce high quality foam which is discharged from the nozzle. The foam generating nozzle of the present invention is simple in construction and, accordingly, the expense of manufacture is substantially reduced, as well as the likelihood of failure during use from clogging, wear and the like.
In one principal aspect, the present invention comprises a foam generating nozzle including a nozzle body and a passage extending through the major part of the body. Orifice means is located adjacent one end of the body to form at least one discrete jet of liquid foam producing agent in the passage along the axis of the orifice means and gas is introduced into the passage through gas inlet means on the nozzle body. The jet of liquid foam producing agent is impinged upon a solid impingement surface in the passage upstream of the discharge end of the body in the path of the jet and on the axis of the orifice means deflecting the jet toward the axis of the passage to effect intimate mixing of the liquid foam producing agent and the gas to generate foam in the passage.
In another principal aspect, the present invention comprises a method of generating foam including forming at least one discrete jet of a liquid foam producing agent in a passage along an axial path, impinging the jet upon a solid surface in the axial path of the jet in the passage, introducing a gas into the passage, and intimately mixing the gas and liquid foam producing agent deflected from the solid surface to generate foam in the passage, and discharging the foam from the passage.
These and other objects, features and advantages of the present invention will become evident upon consideration of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWING In the course of this description, reference will frequently be made to the attached drawing in which:
FIG. 1 is a cross sectioned side elevation view of a preferred embodiment of foam generating nozzle constructed and which operates in accordance with the principles of the present invention;
FIG. 2 is a cross sectioned end view of the nozzle taken substantially along line 2-2 of FIG. 1;
FIG. 3 is an end view of the nozzle as viewed substantially along line 33 of FIG. 1;
FIG. 4 is a cross sectioned side elevation view of another embodiment of foam generating nozzle constructed in accordance with the principles of the invention; and
FIG. 5 is a cross sectioned end view of the nozzle shown in FIG. 4 taken substantially along line 55 of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring particularly to FIGS. 1-3, a first preferred embodiment of nozzle constructed and which operates in accordance with the principles of the invention comprises an elongate nozzle body 10 having an elongate passage, generally 12, extending therethrough. Passage 12 comprises a first passage section 14 adjacent one end 16 of the body and a second passage section 18 adjacent the other end 20 to the body. Passage section 18 is axially spaced from the first section 16 and has a cross sectional dimension smaller than that of the first section. The first and second passage sections 14 and 18 are axially separated from each other by an annular shoulder 22 having a surface 23 which is inclined toward the passage axis a and end 20 of the nozzle body as shown in FIG. 1. This shoulder 22 will be further described in detail hereafter.
End 16 of the nozzle body 10 is stepped to define an annular surface 24 which lies in a plane substantially perpendicular to the axis a of the passage. A circular orifice plate or disc 26 is positioned against annular shoulder 24 and held in position by a lip 28 which is crimped over the other side of the plate as shown in FIG. 1. A plurality of fine orifices 29 and 30 are drilled through the plate 26. The axes of the orifices 29 and 30 are spaced from each other and are radially spaced from the axis a of the passage 12. Preferably the axes of the orifices 29 and 30 extend in a direction parallel to the axis a such that liquid foam producing agent which is jetted through these orifices is also jetted along paths substantially parallel to the axis of the passage and coincident with the axes of the orifices and impinge on surface 23, the jets J being shown in FIG. 1.
The end 16 of the nozzle body is also threaded at 32 to receive a suitable coupling (not shown) which couples the nozzle body with a supply of a suitable liquid foam producing agent. In the alternative, the nozzle body may be positioned in a suitable nozzle cap (not shown) which, in turn, is coupled to a supply of foam producing agent.
A plurality of air inlet apertures 33 and 34 are also bored radially through the nozzle body and into passage section 14 for introducing air into the passage 12, preferably by way of aspiration. The liquid orifices 29 and 30 and air inlet orifices 33 and 34 preferably are offset relative to each other such that the jets J pass between adjacent ones of the air inlet orifices. This arrangement avoids the possibility of liquid droplets building up in the air orifices which might disturb the flow of air through the orifices 33 and 34 and drip from the orifices to the exterior of the nozzle body.
The other end 20 of the nozzle body 10 is formed with a suitable discharge opening 36 for exit of the foam F which is generated in passage 12. This opening, for example, may take the form of a slotted aperture which will eject the foam in a fanshape. The shape of the opening 36 may be varied depending upon the shape of discharge desired.
Having considered the above description, it is believed that the operation of the foam generating nozzle shown in FIGS. 1-3 will be evident. However, for purposes of clarity, the operation of this embodiment of invention will be briefly described.
A source of foam generating agent, such as Fomex, obtainable from Colloidal Products Corporation, Petaluma, California, is coupled to end 16 of the nozzle body 10 and this foaming agent is fed to the plate 26 under a pressure of about 40 psig. Such foam producing agents may, and usually, include commercial foaming agents as diluted with a suitable amount of water or other diluents. In fact, the term foam producing agent as referred to herein may include water only as it has been found that the invention will operate reasonably well with water to which no other commercial foaming materials have been added.
As the foaming agent passes through orifices 29 and 30, a plurality of discrete fine jets J are formed. These jets J are jetted past the gas inlet apertures 33 and 34 in an axial path which is substantially parallel to axis a and the jets impinge the solid inclined surface 23 of shoulder 22 which lies in their axial path. The jets J upon impingement are deflected toward the axis a of the passage where the deflected liquid foam producing agent is thoroughly and intimately mixed in the reduced passage section 18 with the air'which has been aspirated through orifices 33 and 34. The air is aspirated into the passage due to the reduced pressure which is created in passage section 14 due to the presence of the high speed liquid jets J passing the air orifices 33 and 34. The intimate mixing of th deflected liquid foam producing agent and air in passage section 18 produces a high quality foam which is then discharged from the slotted discharge opening.
Referring to FIGS. 4 and 5, a second embodiment of foam generating nozzle and method is shown in which a pintle is positioned in the nozzle body passage to enhance the generation of foam.
In this embodiment the elongate nozzle body 50 includes a passage 52 extending through the body. One end 54 of body 50 is externally threaded at 56 to receive a coupling for coupling the body to a suitable supply (not shown) of liquid foam producing agent under pressure. The passage 52 is also internally threaded at 58 adjacent end 54 to receive a threaded bushing 60 having a fluid inlet passage 62 extending therethrough.
A pintle 68 includes a pair of discs 70 and 71 which are spaced axially from each other along passage 52 by a rod 72 to which they are firmly affixed. Disc 70 is substantially the same diameter as passage 52 and disc 70 is clamped between the internal end 74 of bushing 60 and an annular step located on the passage wall to properly position the pintle 68 in the passage 52. The downstream disc 71 is preferably smaller in diameter than disc 70 to allow the foam to freely flow between its edges and the wall of passage 52.
The shoulder 80 abruptly terminates upstream of a plurality of air inlet orifices 82 which are bored radially through the body 50 for introducing air into passage 52.
A plurality of orifices 84 are also bored axially through the thickness of disc 70. These orifices 84 will form fine jets J on the foam producing agent which aspirate air through orifices 82 and will impinge the upstream face 86 of disc 71 as shown in FIG. 4.
A foam discharge opening is located at the other end 88 of the body 50. This opening may also take the form of a slot 90 formed in a threaded nozzle tip 92 which is threaded onto threads 94 on the body 50.
The operation of the foam generating nozzle shown in FIGS. 4 and 5 is as follows:
The liquid foam producing agent is supplied under pressure to the end 54 of nozzle body 50. This liquid flows through passage 62 in bushing 60 and through the axial orifices 84 to form the discrete thin axially directed jets of liquid J. Upon leaving orifices 84, jets J will create a pressure drop as they pass orifices 82 to aspirate air into passage 52. As jets J further move downstream they will impinge the surface 86 of disc 71 producing turbulence and intimate mixing with the air which has been aspirated into passage 52 to enhance the quality of the foam. The foam thus generated will leave disc 71 and exit from the discharge slot 90.
Although the orifices 82 and 84 are shown in registry with each other in FIGS. 4 and 5, it will be understood that they may be offset from each other for the reasons set forth with respect to the embodiment shown in FIGS. 1-3.
It will also be understood that although the foam generating nozzles described herein are shown having pairs of liquid and air orifices, the number of orifices may be varied without departing from the spirit and scope of the invention. Moreover, it is not intended that the foam generating nozzles and methods of the present invention be construed as being limited to use in agricultural applications only, but are intended to be useful in the generation of foam of widely varying characteristics and uses.
In addition, it will be understood that numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention, the above described embodiments of the present invention being merely illustrative of a few of the applications of the principles of the invention.
What is claimed is:
l. A foam generating nozzle comprising,
a nozzle body having an elongate passage extending through the major part of the length of said body,
a liquid inlet at one end of said body for introducing a liquid foam producing agent to said passage,
orifice means adjacent said one end of said body, said orifice means having an axis and forming at least one discrete jet of liquid foam producing agent in said passage along said axis when said agent is introduced through said liquid inlet,
gas inlet means on said nozzle body between said orifice means and the other end of said body for introducing a gas into said passage,
a solid impingement surface in said passage between said orifice means and the other end of said body positioned in the path of said jet on said axis, said surface deflecting said jet which impinges thereon toward the axis of said passage to effect intimate mixing of the liquid foam producing agent and the gas to generate foam in said passage, and
foam discharge means adjacent said other end of said body, said passage being of substantially constant cross section over its length between said solid impingement surface and said foam discharge means.
2. The nozzle of claim 1 wherein said passage extends axially between the ends of said body.
3. I h e nozzle of claim 1 wherein said orifice means comprises a plurality of orifices spaced radially from the axis of said elongate passage, said orifices forming a plurality of fine jets each of which impinge said solid impingement surface.
4. The nozzle of claim 3 wherein said gas inlet means also comprises a plurality of orifices through said body.
5. The nozzle of claim 4 wherein said gas inlet orifices are positioned between said plurality of liquid orifices and said solid impingement surface and said liquid foam producing agent orifices are offset from each other such that each of said jets pass between adjacent ones of said gas inlet orifices.
6. The nozzle of claim 1 wherein said orifices means comprise a plate positioned at said one end of said passage, said plate having a plurality of orifices therein radially spaced from the axis of said elongate passage.
7. The nozzle of claim 1 wherein said orifice means directs said jet in a path substantially parallel to the axis of said passage.
8. The nozzle of claim 1 wherein said orifice means and said gas inlet means are positioned relative to each other such that the jet issuing from said orifice means reduces the pressure in said passage adjacent said gas inlet means to a pressure below atmospheric pressure, whereby the gas is aspirated into said passage through said gas inlet means.
9. The nozzle of claim 1 wherein said solid impingement surface comprises a shoulder defined on said body in said passage, said shoulder being positioned in the path of said jet.
10. The nozzle of claim 9 wherein said shoulder is annular.
11. The nozzle of claim 9 wherein said shoulder is sloped toward said foam discharge means whereby said jet is deflected toward the axis of said passage.
12. The nozzle of claim 9 wherein said passage comprises a first section and a second section axially downstream from said first section, said second section having a cross section smaller than said first section and being separated from said first section by said shoulder.
13. The nozzle of claim 1 wherein said foam discharge means conprises a slotted opening.
14. The nozzle of claim 1 wherein said gas inlet means is axially positioned between said orifice means and said solid impingement surface.
15. A method of generating foam comprising the steps of:
forming at least one discrete jet of a liquid foam producing agent in a foam generating passage along an axial path,
impinging said jet upon a solid surface in said axial path of said jet in said passage, introducing a gas into said passage downstream of the location at which said fine jet is formed,
intimately mixing said gas and the liquid foam producing agent deflected from said solid surface together to generate foam in a portion of said passage having substantially constant cross section over its length, and
discharging said foam from said portion of said passage.
16. The method of claim 15 including forming a pluraltiy of said jets of said liquid foam producing agent and directing said jets along a path substantially parallel to and radially spaced from the axis of said passage, each of said jets impinging upon said surface.
17. The method of claim 16 wherein said jets impinge upon an annular surface in said passage.
18. The method of claim 15 wherein said jet is deflected toward the axis of said passage by impingement upon said solid surface.
19. The method of claim 15 wherein said gas is introduced into said passage upstream of said solid surface.
20. The method of claim 15 wherein said solid surface includes a disc in said passage downstream of the location at which said gas is introduced into the passage.