US2613992A - Self-cleaning spray nozzle - Google Patents

Description

1952 A. H. BAHNSON, JR 2,613,992

SELF CLEANING SPRAY NOZZLE Filed Nov. 5, 1948 Patented Oct. 14, 1952 UNITED STATES PATENT OFFICE 2,613,992 v I I SELF-CLEANING SPRAY NOZZLE Agnew lLBahnson, Jr., Winston-Salem, N. C.

Application November 5, 1948, Serial No. 58,475

4 Claims.

1 This invention relates to .nozzles for creating a mist or a more or less finely divided spray of water or other liquid delivered under pressure for use particularly in washing or humidifying air.

One of the principal problems encountered with these nozzles is the clogging of one or more of the many small apertures, through which the liquid is passed in forming the spray, by small particles of dirt or other foreign matter that may and usually are entrained with the liquid. Filter screens have been proposed for trapping these particles but these have not proven entirely satisfactory. If the screen mesh is made fine enough to adequately stop all foreign matter, it causes too great a drop in nozzle pressure, and if made coarse enough so as to not materially affect the nozzle pressure, the interstices in the mesh are too large to block the particles. Then too, the filters must be removed and cleaned periodically and this adds to the maintenance cost.

It has also been proposed to use cleaners of the automatic type, built into the nozzle, and

which perform a cleaning operation each time that the nozzle is turned on, or off, depending upon the construction, but these are not suitable for spray nozzles of the type in which the apertures are distributed around and extend substantially laterally from a barrel type distribution head.

The general object of this invention is to provide 'an improved self-contained type of nozzle cleaner for multi-apertured nozzles of the above-described type and which operates automatically each time the nozzle is put into operation thus eliminating the necessity for disassembling and reassembling the nozzle each time that cleaning becomes necessary, and also assuring a continuous, high quality spray.

Another object is to provide a cleaner unit for spray nozzles having a minimum of parts and which is simple and inexpensive to manufacture and service.

The foregoing as Well as other objects and advantages inherent in the improved construction will become more apparent from the vfollowing detailed description of a preferred form of the invention and from the accompanying drawings in which Fig. 1 is a longitudinal central section through the improved nozzle;

Fig. 2 is an end elevation looking towards the left in Fig. 1;

Fig. 3 is a transverse section taken on line 33 of Fi 1, and

Fig. *4 is a view in perspective of the piston used to clear the nozzle apertures.

Referring now to the drawings, the nozzle is seen to be comprised of a cylindrical metal barrel, one end of which is threaded at 2 for attachment to a pipe, not shown, through which the liquid is delivered to the nozzle. To establish-a fine spray efiect, a, plurality of small diameter apertures .3 extending through the barrel are used, and these are arranged in sets of two each around the circumference of the barrel .in two axially spaced rows. The generally laterally extending apertures of each set are preferably arranged at a converging angle such that the respective streams of liquid flowing therethrough will impinge upon each other at a point .iairly close to the exterior surface of the barrel I thus breaking up the streams into a mist of very fine liquid particles. The walls of the apertures 3 are also .seen to possess a taper divergent in the direction of flow for a purpose that will be later explained.

.In addition to the two main circumferential arrays of sets of aperture '3, the nozzle barrel ,1 is also provided with a pair of apertures 4 at the end opposite the threaded end 2. These apertures are likewise set at an angle to each other and deliver a generally diverging conical mist centering about the extended longitudinal axis of the barrel I. For convenience in manufacture, the apertures 4 are formed in a central plug 5 stemmed at .6 to facilitate removal and which is threaded into a plug 1 of larger diameter that is in turn threaded into the end of the barrel l. The head 8 of plug .1 is given ,a hexagonal or some other polygonal shape for receiving a wrench, as is also the barrel l at 9, and contains an axial aperture lll spaced from the confronting end wall of plug 6 to permit passage of the liquid discharged through the set of end apertures 4.

In accordance with the present invention, the improved, automatically operating cleaning device for the main group of nozzle apertures 3 is comprised of a piston H located within the barrel 1 and which works against a coil spring 12. The right end of spring 12 as viewed in Fig. 1 extends into a well portion it of reduced diameter in the barrel for supporting and maintaining the several turns of the spring in axial alignment as it expands and is compressed, while the left end of the spring is seated in an annular groove 14 in the end face l5 of piston H.

Piston II is reduced in diameter intermediate its ends thus establishing a central portion I6 of reduced diameter and end flanges I1 and I8 the diameters of which are substantially the same as but slightly less than the internal diameter of the barrel I so as to permit a close sliding fit between the piston flanges and the barrel wall. Also the left end flange I! is seen to contain a plurality of axially extending openings I9 to permit free flow of the liquid therethrough. Finally to keep piston II and spring I2 in place and establish a starting position for the piston, a retaining sleeve 20 is used. This sleeve is inserted in the left end of the barrel and is provided with an external stop shoulder 2I adapted to abut against the end face of the nozzle barrel.

Operation of the cleaning device is as follows:

With the nozzle cut off from the pressure liquid, piston II and spring I2 occupy respectively the positions shown in full lines in Fig. 1. When, however, the liquid is introduced into the nozzle body I at the left end, the pressure of the same acting principally against the imperforate piston flang I8 forces piston II to the right. During this movement, the piston end flanges l1 and I8 in sliding past the entrance edges of the apertures 3 shear off or agitate loose any dirt or other foreign matter that may have lodged at the entrances to one or more of the apertures and the normal pressure of the liquid is thus suflicient to force the foreign matter out through the apertures. The latter because of their divergent taper provide free passage of the particles and this serves to prevent reclogging the apertures proper.

Piston II stops when it reaches the position shown in broken lines with spring I2 fully compressed and the piston end flange I8 to the right of the row of apertures 3 nearest the right end. The main portion of the liquid thus flows freely through all of the apertures 3. A minor portion of the liquid, however, escapes past end flange I8 between the rim of the latter and the wall of the barrel and enters the end apertures 4 to form the auxiliary end spray. While the amount of liquid flowing through apertures 4 constitutes but a minor portion of the total supplied, its rate of flow is nevertheless sufficient to maintain a reduced pressure condition on that side of the piston flange I8 nearest the end apertures 4 with the result that piston I I will be maintained in the position shown in broken lines so long as the pressure behind the liquid is maintained. However, when the pressure is turned off, the restoring force built up within spring I2 due to its compression is now free to exert itself and thus pushes piston I I back to its initial position shown in full lines. Piston I I obviously executes a second clearing action of the entrance edges of the apertures 3 during the return stroke.

Normally a single stroke of piston I I is all that is needed to clean out any foreign matter which may have accumulated. However, if a particularly bad clogging condition arises, the cleaning cycle may of course be repeated as many times as necessary merely by turning the liquid pressure on and oil.

In conclusion, it is to be understood that while the illustrated construction is to be preferred, various modifications thereof may occur to and possibly be preferred by others who may seek to practice the invention but without, however, departing from the spirit and scope of the invention as defined in the appended claims. Thus, for example, if in certain applications an end spray is not considered advantageous or indeed should become undesirable, the set of end orifices 4 may be dispensed with and an air bleed substituted therefor to prevent a counterpressure from being built up on the end of piston I I opposite to that of the liquid pressure as the piston moves to the right. In such a case the imperforate piston end flange I8 would be modified so as to present a closer fit with the wall of barrel I, a packing ring being used if necessary, to prevent an of the liquid from leaking past the piston to the air bleed side.

Having now fully described my invention and illustrated a preferred constructional embodiment of the same, I claim:

1. A self-cleaning spray nozzle comprising a cylindrical barrel having a fluid inlet at one end thereof adapted to be connected to a source of fluid under pressure and a plurality of apertures spaced longitudinally along and extending outwardly through the barrel wall in a generally lateral direction, a piston slidable within said barrel having a diameter substantially equal to the internal diameter of said barrel so as to wipe across the inlet edges of said apertures, a helical loading spring in said barrel for said piston, one end of said spring being fixed and the other end thereof being engaged with one face of the piston and biasing the latter to a starting position at the fluid inlet end of said barrel, a removable sleeve disposed within said barrel at the fluid inlet end thereto, the end face of said sleeve within said barrel constituting a stop for said piston and establishing the said starting position for the piston, the opposite face of said piston when in said starting position being subject to pressure from the fluid when admitted to said inlet, and causing said piston to be driven from its starting position along said barrel past said apertures and to compress said loading spring.

2. A self-cleaning spray nozzle as defined in claim 1 wherein the opposite end of said sleeve includes a shoulder abutting the end face of said barrel.

3. A self-cleaning spray nozzle comprising a cylindrical barrel having a fluid inlet at one end thereof adapted to be connected to a source of fluid under pressure and a plurality of apertures spaced longitudinally along and extending outwardly through the barrel wall in a generally lateral direction and a well portion at the other end of said barrel provided with an aperture extending from the base of the well portion through the end wall of the barrel in a direction generally longitudinally of the barrel, a piston slidable within said barrel having a, diameter substantially equal to the internal diameter of said barrel so as to wipe across the inlet edges of said laterally extending apertures, a helical loading spring in said barrel for said piston, one end of said spring being received in said well and the other end of said spring being engaged with one end face of said piston and biasing the piston to a starting position at the fluid inlet end of said barrel, the

opposite end face of said piston when in starting position being subject to pressure from the fluid when admitted to said inlet and causing said piston to be driven from its starting position along said barrel past said laterally extending apertures and to compress said loading spring.

4. A self-cleaning spray nozzle as defined in claim 3 wherein the portion of said piston intermediate its ends is of reduced diameter to establish end flanges and the end flange adjacent the I 6 v fluid inlet to said barrel is apertured axially, the Number Name Date other end flange being imperforate. 1,180,807 Vedder Apr. 25, 1916 AGNEW H. BAHNSON, JR. 1,416,401 Dudley May 16, 1922 1,762,313 Snow et a1 June 10, 1930 REFERENCES CITED 5 1,879,012 Armstrong Sebt. 27, 1932 The following references are of record in the 2,096,307 Hulberb Q 1937 file of this patent: -gg Foster O 3. 322

2, 43, Latter Mar. 1 UNITED STATES PATENTS 2,466,182 Peeps Apr. 5, 1949 Number Name Date 10 405,015 Crance June 11, 1889

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