US2569683A - Airfoam nozzle - Google Patents

Description

Patented Oct. 2, 1951 AIRFOAM NOZZL'E Charles H. Lindsay, Elmira, N. Y., -assignor to American La France Foamte Corporation, Elmira, N. Y., a corporation `of New York Application February 5, 1946, Serial No. 645,593

2 Claims. l

The invention relates tothe production and discharge of airioam, as from a form 4of handheld device adapted to mix and convert into kairfoam appropriate ingredients supplied `to it and also adapted to serve as a nozzle for discharging and directing the resulting airfoam. The primary object of the invention is a method and apparatus applicable to foam-forming devices in general, but vof particular utility for improving the stream and discharge characteristics of airfoam nozzles. l

For purposes of illustration only, the invention is shown and described herein as incorporated in a preferred form of nozzle which, as to features other than those claimed herein, is the subject of a co-pending application, Serial No. 645,592, filed February 5, 1946, now Patent No. 2,513,417, dated July 4, 1950.

In the drawings, Fig. I is a broken-out longitudinal section through the preferred form of nozzle incorporating an illustrative form of the invention; Fig. II is a section on the line II-II of Fig. I (with part of the background omitted for the sake of clearness) and Fig. III is a crosssection on the line III-III of Fig. I.

The nozzle illustrated consists of a cast body, generally designated I, and a pipe section, generally designated 2, the former serving as a supply unit by means of which the ingredients are introduced, and the latter serving as a receiver within which the airfoam'is formed and by which it is discharged.

The body I comprises an integrally formed tubular hub 3 encircled by a rim or sleeve portion 4, the two being united by an intervening spider 5. As shown, the rim overhangs the spider on both sides. The front face of the spider (meaning the right-hand side as viewed in Fig. I) is recessed, as at 6, and the pipe section 2 is telescoped into the recess. By making the recess of adequate depth to provide a substantial length of bearing for the pipe section, the latter may be rigidly locked in position, abutting the spider face, by means of screws l extending radially' inwardly from the periphery ofthe rim and through the intervening portion of the spider.

As shown more particularly in Fig.. II, the spider apertures, 8, of which there are four in this instance, extend substantially from the hub to the rim; and the diameter of the recess 6 and the pipe section 2 are such that the latter intersects the apertures intermediate the hub and the rim. When the interior of the pipe section is under suction (as presently described) external air is thus free to ow from front to rear of the spider lli , same time.

2 in the outer portions of the apertures 8, that is, between the pipe section and the rim; and air is likewise free to flow directly to the rear face of the spider and into the pipe section through Vthe inner portions of the apertures 8, that is, between the pipe section and thehub. With this arrangement it is virtually impossible for anyone handling the playpipe inadvertently to block off thev air supply and thereby interfere with satisfactory foam formation within the nozzle. Without conscious attention the person handling the nozzle can grasp it `as happens to be most convenient. If, by chance, his hand happens to obstruct the Iiow of air into the nozzle directly from the exterior to the rear iace of the spider, it is-of no material consequence, because free air flow is still provided for from the front face of the spider between the rim and the nozzle as above described. Similarly, an adequate air supply Vby way of the direct or rear inlet is provided notwithstanding inadvertent obstruction of the front air inlet. It will be understood that While the Width of the rim is not critical, it should be such that even a heavily-gloved hand grasping it will not obstruct both inlets at the It will also be recognized that by making the dual air inlet structure an integral part of the body portion of the unit, as is preferred, an extremely rugged structure is provided.

The central bore of the hub 3 is formed with sections of two diameters. In this instance, the section of the bore which extends forwardly from: aboutv the center line of the spider to the front end of. the hub is of substantially uniform diameter throughout; and the rear section of the bore is of a greater diameter and internally threaded to receiveV a water nozzle member il. As illustra-ted, the member 9 is arranged to project a stream o-f water into the forward or receiver section of the bore so as to create suction in the space I0 surrounding the member 9. Communieating'. with the space I-Eiis a radial inlet II incorporated inthe enlarged spoke I2 of the spider and adapted` for connection to a source of supply of airfoam liquid.

Fromthe rear end of the unit projects a flange I3 onl which is mounted a hose coupling collar I 4, a strainer I5 preferably being provided to exclude` large particles of foreign matter from the unit. As will be observed, the flange I3 and the collar I4 are so dimensioned and located as not to obstruct the entry of air directly to the rear face of the spider and thence into the pipe section or main receiver 2.

In the normal course, the stream of water and airfoam liquid emerging from the forward end of the hub bore diverges and strikes the wall of the pipe section, the forward flow of the stream thus creating the suction which draws air into the pipe section in the manner above described. Preferably, means are provided for spreading the emerging stream at a somewhat greater angle (and hence causing it to strike the receiver wall sooner) than would otherwise be the case, a greater length of the receiver thereby being made available for the thorough incorporation of the air with the liquid to form foam. In order to minimize interference with the How of the stream emerging from the hub bore, such means may consist of a conical spreader I5 of the form commonly used in garden hose nozzles and positioned by means of four slender spokes I6 which are clamped against the front end of the hub by a nut member I'I.

As illustrated, and as is preferred, the receiver 2 is of generally uniform diameter throughout the major portion of its length; but, unless otherwise controlled, the emerging stream of airfoam is not of an ideal character from the standpoint of uniformity and range of discharge. It has been found that the stream is very much improved in both these respects by selectively controlling its velocity within and adjacent the outlet end of the receiver in such manner that the entire stream throughout its cross-section travels at about the same speed. Left to its own devices, the stream exhibits substantial differences in velocity throughout its cross-section, it being materially slowed down at its skin or outer surface due to friction between it and the receiver wall. The core of the stream, on the other hand, is not so hindered and emerges at a higher velocity. The stream as a whole, after it has emerged, is thus less uniform or solid and its range is adversely affected, particularly when projected in a strong breeze.

In general, the desired control is affected by slowing down the core of the stream to conform its velocity substantially to that of its skin; and this may conveniently be done by mounting in the receiver, toward its outlet end, a tear drop shaped baffle I8 supported by thin struts or ribs I9. The core of the stream is thus itself subjected to frictional resistance comparable to that experienced by the skin of the stream.

To insure maximum range, the receiver is preferably provided with a short outlet tip 20 of a diameter slightly less than that of the receiver proper, the tip being coupled to the receiver by a tapered section 2l. As indicated, the tip 20 may be provided with a protective ring 22 of rubber or the like. Optimum conditions are found to obtain when the cross-sectional area of the annular stream as it passes the baille I 8 is substantially equal to the cross sectional area of the tip 20. While, of course, the dimensions of the parts are subject to variation as may be convenient or preferred, it may be noted that the proportions indicated by the following are productive of excellent results: diameter of main section of receiver, about 21/2; maximum diameter of the tear drop baffle, about 11/8; diameter of outlet tip, about 2".

While the nozzle has been described primarily with reference to its use for so-called portable operation, in which the airfoam liquid supply is usually carried by the person handling the nozzle, it willbe understood that it is equally adaptable for use in conjunction with motorized apparatus. In the latter case, as is well known, the airfoam liquid is or may be conveniently mixed Awith the water stream at or near the water pump, so that the nozzle receives already-mixed airfoam liquid and water by way of the hose coupled to it by collar I4, the nozzle otherwise functioning just as described.

In the light of the foregoing specific description, for illustrating purposes only, of a preferred form of the invention and its principles, the following is claimed:

1. An airfoam nozzle comprising the combination of an ejector for a water-airfoam liquid mixture, a tubular receiver section of substantially uniform diameter receiving and confining the stream discharged by the ejector, with an air inlet port to the interior of said section on the upstream side of the discharged liquid, a succeeding section tapering in the direction of flow, a tear drop shaped baille fixedly supported axially in the latter section, the length of the bale from its maximum diameter to its forward end being substantially equal to the length of said tapered section and its outer surface, with the surface of said tapered section, defining an annular passage, and an adjoining outlet section of a uniform cross-sectional area substantially equal to that of the said annular passage.

2. An airfoam nozzle comprising the combination of an ejector for a water-airfoam liquid mixture, including spreader means for expanding the discharged liquid into a stream of diverging form and a tubular passage section receiving and confining said stream, with an air inlet port to the interior of said section on the up-stream side of the diverging portion of the discharged liquid; an annular passage section of smaller cross-sectional area than the tubular section and forming a continuation thereof and an outlet section of substantially the same cross-sectional area as the annular section and forming a continuation thereof.

CHARLES H. LINDSAY.

REFERENCES CITED The following references are of record in the l'lle of this patent:

UNITED STATES PATENTS Number Name Date 245,168 Hopkins Aug. 2, 1881 259,667 Churchman June 20, 1882 654,891 Haley July 31, 1900 998,762 Faller July 25, 1911 1,048,004 Strebig Dec. 24, 1912 1,148,630 Schmidt Aug. 3, 1915 1,496,338 Haley June 3, 1924 1,816,417 Witter July 28, 1931 1,874,209 Schnabel Aug. 30, 1932 2,183,561 Hamblin Dec. 19, 1939 FOREIGN PATENTS Number Country Date 417,620 Great Britain Oct. 9, 1934

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