GB2256818A

GB2256818A - Spray nozzle

Info

Publication number: GB2256818A
Application number: GB9213084A
Authority: GB
Inventors: Rupert Oliver Birchenal Cooper
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-06-22
Filing date: 1992-06-19
Publication date: 1992-12-23
Anticipated expiration: 2012-06-19
Also published as: GB9113537D0; GB2256818B; GB9213084D0

Abstract

A spray nozzle intended for fixing to the spray bar of a conventional spraying machine has a main body 10 in which is formed an axial bore 11 closed at the lower end, a plurality of radial distribution holes 14 extend through the main body wall, in radial direction, and preferably intersect each other in the region of the bore 11. In this way, a chamber of increased cross-section is formed in the bore, adjacent the holes 14, by which the liquid fertiliser may be distributed in relatively large-sized droplets. <IMAGE>

Description

SPRAY NOZZLE This invention relates to a spray nozzle intended for use with liquid fertilisers.

The spraying of chemicals (such as insecticides or fertilisers) on growing crops, or on ground in which crops are to grow, has to be precisely controlled in order to achieve the optimum effect: too much chemical is wasteful and so expensive, and may in any event damage the plants; whereas too little chemical will not achieve the desired results. As a consequence, there have been many designs of agricultural sprayer intended to allow the precise and accurate control of the amount of chemical sprayed per unit area of ground. Most such equipment has a spray bar to which the liquid chemical is supplied under a known pressure, the spray bar having a plurality of bosses to each of which a respective spray nozzle may be connected.Each such spray nozzle typically is tubular with an orifice at its lower end of a precisely controlled size and configuration, whereby liquid issuing from the nozzle will be broken into a spray of very fine droplets, the application rate being a function of the pressure in the spray bar and the configuration of the spray nozzle. The exit orifice from the spray nozzle may be configured in a variety of ways, to ensure that a spray of small droplets is created, in the requiredspray pattern.

A particular problem arises in the case of spraying liquid fertilisers. Generally speaking, it is preferred for these to be sprayed in relatively large droplets which thus tend not to stay on any foliage, but instead fall quickly to the ground, in order to minimise damage to growing plants. Merely increasing the size of the exit orifice of a conventional spray nozzle does not achieve the required result of large droplets spread over a significant area; rather, the liquid then tends simply to run out of such a nozzle and so only a very small area of cover is achieved.

This invention aims at providing a spray nozzle adapted for use with a spraying machine and which is able to generate a spray of relatively large droplets, distributed over a sensible area.

According to the present invention, there is provided a spray nozzle suitable for distributing liquid fertiliser from a spraying machine having a spray bar to which the liquid fertiliser is pumped, which spray nozzle comprises a main body of generally tubular form and adapted to fit to the spray bar so as to depend substantially perpendicularly downwardly therefrom, the main body having an axially extending bore closed at the lower end thereof, a plurality of distribution holes formed generally radially through the body adjacent the closed end to communicate with the bore, and a metering orifice the cross-sectional area of which is less than the total combined crosssectional area of the distribution holes.

It will be appreciated that though the spray nozzle of this invention is intended for use with a conventional spraying machine, it is specifically adapted to provide relatively large droplets, which droplets are distributed as they are sprayed from the nozzle, so that the liquid fertiliser sprayed from a machine fitted with such nozzles will cover the ground over which the spraying machine is traversed. This is achieved by virtue of the distribution holes extending generally radially with respect to the main body axis and thus extending more or less in a horizontal plane, when in use. Moreover, by virtue of the relatively large sizes of the distribution holes, the liquid fertiliser is not broken into a fine mist of small droplets; instead, the liquid is sprayed in a relatively large droplet form.

The metering orifice may be defined by the bore in the main body itself, by forming at least a section of that bore to have a predetermined and controlled diameter, selected having regard to the nature of the liquid fertiliser and the pressure at which that fertiliser is pumped to the spray bar. Alternatively, the metering orifice may be defined by a separate plate adapted to be fitted between the main body and the spray bar, so as thereby to perform a metering function for fertiliser delivered to the nozzle.

In order to assist the distribution of the liquid fertiliser in a large droplet form, it is preferred for there to be within the body of the nozzle, adjacent the closed end thereof, a chamber of increased crosssectional area relative to the bore in the body.

Advantageously, the distribution holes in the body open into this chamber within the body. Depending upon the relative sizes of the bore in the body, the body wall thickness and the diameter of the distribution holes, said chamber may be formed by the distribution holes themselves opening into the bore in the body. This may be achieved by having each of the distribution holes running into its neighbouring distribution holes, in the region of the bore in the body. In this way, the bore in the body is effectively enlarged by the intersecting distribution holes, so defining said chamber.

In the most preferred arrangement, the axis of each distribution hole lies substantially wholly in a true radial plane of the bore of the body, and in that arrangement the axis of each distribution hole also substantially extends in a true radial direction with respect to the bore in the main body. However, the axis of each distribution hole could lie at some angle to the true radial plane - for example, each hole may be inclined downwardly towards its free end perhaps at o 10 . Similarly, each hole may extend at an angle to the true radial direction, so in effect having a tangential component. Of course, both of these possibilities may be used at the same time, in one spray nozzle.

A conventional spraying machine has a spray bar with a plurality of bosses provided thereon, each of which is adapted to receive a so-called cap normally connectable to a boss by means of a screw-thread or bayonet-type connection. In such an arrangement, the spray cap has a central opening in which a user may position a spray-nozzle of his choice; it is preferred for the spray nozzle of this invention to be adapted for use with such spraying machines, and so to have a main body which defines an integral cap connectable to a spray bar boss. As an alternative, the main body may have an outer diameter which corresponds to the diameter of the opening in a separate cap, and a flange formed on the body at its upper end which flange is locatable within the cap, for sealing against a boss of the spray bar when the cap is fitted thereto.In either case, a sealing washer or ring may be provided to enhance the seal against the spray bar boss, if required.

The distribution characteristics of the sprayed liquid may be enhanced by ensuring that the outlet planes of no two distribution holes lie on the same line parallel to the normal direction of movement of the spray nozzle, when in use. This may be achieved in one of two ways: either the angular spacing between the distribution holes may be non-uniform; or, for a nozzle with uniformly-spaced distribution holes, the nozzle may be set at such an angle with respect to the normal direction of movement that the criterion is satisfied.

In the case of a nozzle having an even number of distribution holes spaced by aO of arc (for example, eight holes spaced by 450 of arc), the nozzle may be set with the common axis of two diametrally-spaced holes at (a/4)0 to the intended direction of movement of the nozzle, when in use (and for the nozzle mentioned above, at 11.250 to the direction of movement).

It is most advantageous to employ a bayonet-type connector for a nozzle to be set as described above, for the co-operation between the pins and slots of the connector may define the angular setting of the nozzle.

For this, the main body is conveniently formed integrally with the cap, or the main body should be connected or secured to the cap in a non-rotatable manner, in order to ensure the relationship between the grooves of the cap and the discharge holes of the nozzle remains fixed, presuming the pins of the bayonet-type connector are formed on the boss of the spray bar.

By way of example only, two specific embodiments of spray nozzle according to the present invention will now be described in detail, reference being made tithe accompanying drawings in which:- Figure 1 is a part-sectional side view of the first embodiment of spray nozzle of this invention, together with a spraying machine cap; Figure 2 is a sectional view taken on line II-II marked on Figure 1; Figure 3 shows a modified form of spray nozzle of this invention; Figure 4 is a diagrammatic plan-view of the nozzle of Figures 1 and 2, showing the distribution pattern; Figure 5 is a diagrammatic plan view of spray nozzle similar to that of Figure 1, but having a different arrangement of distribution holes; and Figure 6 is a partial view on a spray bar, showing a boss for a spray nozzle.

The embodiment of spray nozzle shown in Figures 1 and 2 of the drawings comprises a one-piece injection moulding having a main body 10 in which is formed a metering bore 11, extending from the upper end 12 of the nozzle towards the lower end 13, where the bore is closed. Extending radially through the main body 10, adjacent the lower end 13 thereof, are eight distribution holes 14, disposed symmetrically around the body 10 and each having its axis in a common radial plane. As best seen in Figure 2, each bore 14 has a diameter sufficiently great to run into the next adjacent bores; as a consequence, the effective crosssectional area of the bore 11 is increased in the region of the distribution holes 14, intersecting at their inner ends.This defines a chamber 15 within the nozzle from which liquid fertiliser passes to the distribution holes, in turn ensuring that the liquid is not disassociated into a fine spray of small droplets, on leaving the distribution holes 14; instead, the liquid leaves the nozzle in the form of relatively large droplets which do not tend to adhere to foliage but instead fall to the ground.

As can also be seen in Figure 1, the main body is formed integrally at its upper end 12 with a cap 20 for attaching the nozzle to a boss (Figure 5) of a spray bar of a known kind of spraying machine (not shown).

This cap 20 has a cylindrical side wall 21 with an inturned flange which connects to the main body 10. The side wall 21 has a pair of opposed bayonet attachment grooves 22, for engagement by projecting pins 30 from the boss 31 of the spray bar 32 (Figure 6), in a manner known in the art; such a bayonet connector will not therefore be described in detail here. Also, a resilient sealing washer 23 is located in the cap 20, to effect a seal against the spray bar boss 31, again in a manner known in the art.

In use, the bosses of the spray bar of a spraying machine are all fitted with essentially the same nozzles. Since the orientation of the pins 30 on each boss is fixed, in alignment with the length of the spray bar, and the disposition between the grooves 22 and the discharge holes 14 is also fixed, each nozzle has the same relative orientation to the spray bar.

When liquid fertiliser is pumped to the spray bar at a pre-selected pressure, it will be distributed through the attached nozzles and discharged out of the holes 14. By virtue of the disposition of the distribution holes 14, a generally circular spray pattern is obtained, of relatively large droplets - which is most advantageous for a liquid fertiliser.

As shown in Figures 2 and 4, the nozzle is orientated with respect to the direction of movement of the spray bar such that a series of lines B all parallel to the direction of movement A and drawn through the intersects of the axes of the distribution holes 14 and the outer circumference of the nozzle are all spaced from one another, with only one distribution hole lying on each line. It can be demonstrated that with an even number n of distribution holes, the angle a between the holes is (360/n)", and by setting the axis of two diametrally-opposed holes at (a/4)0=(90/n)0 to the direction of travel, this advantageous condition can be achieved. Once done, an optimum spray pattern over the ground will be obtained, without significant double-coverage of some regions and without minimal or no coverage of other regions.

In the modified embodiment shown in Figure 3, like parts with those of Figures 1 and 2 are given like reference characters and will not be described again here. In this embodiment, the bore 11 is counter-bored from the lower end 13 of the body 10, thereby defining a shoulder 25 part-way along the length of the bore, above which the bore 11 serves to define the metering orifice for liquid fertiliser supplied under pressure to the nozzle. The lower end 13 of the bore is closed by a screw-threaded plug 26 fitted into the counterbore. In this way, a chamber 15 of enlarged crosssectional area is defined, into which the distribution holes 14 communicate. This arrangement allows the furnishing of distribution holes of a smaller diameter as compared to those of Figure 1, whilst still having a chamber of enlarged cross-sectional area adjacent the inner ends of those holes.

Also shown in Figure 3 is an anti-drip valve, comprising a ball 27 urged by a spring 28 acting against the plug 26, into engagement with the shoulder 25. The ball will lift away from that shoulder 25 against its spring bias when liquid is pumped under pressure to the spray nozzle, but when the supply of liquid under pressure is removed, the ball will seat against the shoulder 25 and close off the bore 11.

Figure 5 diagrammatically shows a further embodiment of nozzle similar to that of Figures 1 and 2 and like parts are given like reference characters.

The nozzle differs in that the distribution holes 14 are irregularly spaced around the periphery of the nozzle, unlike the case with the nozzle of Figures 1 and 2. By angularly spacing the distribution holes as shown in Figure 5, the outlets therefrom are spaced uniformly across the normal direction of movement A of the nozzle. In this way, an optimum spray pattern can be obtained, without significant double-coverage of the same region on the ground, and without minimal or no coverage of other regions.

Claims

1. A spray nozzle suitable for distributing liquid fertiliser from a spraying machine having a spray bar to which the liquid fertiliser is pumped, which spray nozzle comprises a main body of generally tubular form and adapted to fit to the spray bar so as to depend substantially perpendicularly downwardly therefrom, the main body having an axially extending bore closed at the lower end thereof, a plurality of distribution holes formed generally radially through the body adjacent the closed end to communicate with the bore, and a metering orifice the cross-sectional area of which is less than the total combined cross-sectional area of the distribution holes.

2. A spray nozzle according to claim 1, wherein the metering orifice is defined by the bore in the main body itself, which bore has at least a section of a predetermined and controlled diameter, selected having regard to the nature of the liquid fertiliser and the pressure at which that fertiliser is pumped to the spray bar.

3. A spray nozzle according to claim 1, wherein the metering orifice is defined by a separate plate adapted to be fitted between the main body and the spray bar.

4. A spray nozzle according to any of the preceding claims, wherein there is formed within the body of the nozzle, adjacent the closed end thereof, a chamber of increased cross-sectional area relative to the bore in the body.

5. A spray nozzle according to claim 4, wherein the distribution holes in the body open into said chamber formed within the body.

6. A spray nozzle according to claim 5, wherein said chamber is formed by the distribution holes intersecting each other where those holes open into the bore in the body.

7. A spray nozzle according to any of the preceding claims, wherein the axis of each distribution hole lies substantially wholly in a true radial plane of the bore of the body.

8. A spray nozzle according to any of the preceding claims, wherein the axis of each distribution hole substantially extends in a true radial direction with respect to the bore in the main body.

9. A spray nozzle according-to any of claims 1 to 6, wherein the axis of each distribution hole lies at a shallow angle to the true radial plane.

10. A spray nozzle according to any of claims 1 to 6 or claim 9, wherein each distribution hole extends at an angle to the true radial direction.

11. A spray nozzle according to any of the preceding claims, wherein a non-return valve is fitted into the bore in the main body, above the distribution holes formed therein.

12. A spray nozzle according to any of claims 1 to 10 and including a cap to attach the nozzle to the spray bar of a spraying machine, which cap is configured to pre-set the disposition of the distribution holes of the nozzle relative to the spray bar.

13. A spray nozzle according to claim 1 and substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.