AU615500B2 - Spray head - Google Patents

Description

0 0 0006..

0 0 WAIKERIE CO-OPERATIVE PRODUCERS LTD

R.K....ADDER.

By its Patent Attorneys, R.K. MADDERN ASSOCIATES.

TO:

THE COMMISSIONER OF PATENTS, CANBERRA, A.C.T.

NEW Iww 0 ~k 615500 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-62 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Form Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Prioritl': ego* 000 R 611te;i Art: Class Int. Class Ngm~of Applicant A Ore~s of Applicant: a.: Actual Inventor

SOS.

A;dre*s for Service: TO BE COMPLETED BY APPLICANT WAIKERIE CO-OPERATIVE PRODUCERS

LTD.

Corner Crush Terrace and Sturt Highway, Wai keri e, State of South Austral ia Commonwealth cf Australia Victor PI CKFORD care of R.K. MADDERN ASSOCIATES, 345 King William Street, Adelaide, South Australia, 5000 Complete Specification for the Invention entitled: "SPRAY HEAD" The foIIowl~g statement Is a full description of this Invention, includhig the best method of performing it I, known to ri Us.

'PATNTR~DE MARKS1 TO: The Commissioner of Patents Commonwealth of Australia' R K MADDERN ASSOCIATES Citicorp House 345 King William Street Adelaide South Australia 5000 7- Ki* r This invention relates to a spray head which is useful for spraying insecticides in an orchard, but can also be used for other puirposes such as spraying herbicides.

Spray heads have occupied many different shapes and configurations, and for example the reader can refer to the Australian Patent Application No. 84362/82 which illustrates a spray head constituting the closest prior art known to the applicant.

When liquid is to be formed into small droplets for spraying purposes, one of the problems has been that the liquid discharges through apertures internally of Ta cylindrical type spray head but tends to move to the S* 0 forward or downstream end, and because of this the range of droplet size varies very widely. In some instances the problem is so serious that spray is not developed properly, and for this reason various measures have been Staken in the past. For example in the above-identified application, use has been made of vanes, and an internal il0 perforate cylinder which lies within a second perforate Scylinder itself within a mesh cylinder. Even with such a complicated arrangement however, it has been difficult to achieve satisfactory results, the arrangement only partly rectifying the problem of droplet size and even distribution.

-2- 47 he lqui dichares hrogh aertresintenaly o cy ind ical type spr y he d b t te ds t mo e fc th The main object of this invention is to provide improvements whereby there is an even distribution of droplet size of liquid which is to be sprayed. It has for agricultural spraying purposes is between 80 and 140 microns diameter, but the current state of technology achieves only about 20% of droplet size in that range, and the droplet size can vary between 20 and 800 microns.

With the object of providing a spray head which is specifically useful for but not limited to agricultural applications, in an embodiment of this invention the spray head consists of mounting means, a motor carried on the mounting means, a rotary distribution drum coupled for drive to the motor, and a liquid discharge nozzle, said 5 distribution drum being of general cup-like shape, having an end portion and a generally cylindrical portion projecting from the end portion, the cylindrical portion having a series of bars extending axially and being circumferentially spaced by slots, the inner surface of 0 each bar being concave in a radially outward direction S thereby forming a miniature liquid reservoir, the liquid 10 discharge nozzle being so oriented as to discharge liquid into the cup-like drum, the cup-like drum having internal distribution surfaces which, upon rotation of drum by the motor, distribut3 the discharged liquid into the miniature reservoirs from which the liquid discharges and flows i

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i l H I[ It It has been found that with this invention a droplet size range between 65 and 85 microns can constitute as much as 51% of the entire spray, and between 113 and 160 microns, as much as 32%, and that more than 60% will lie within the desired range.

This invention results in a very even distribution because centrifugal force of a rotating drum is very much greater than gravity force which can be substantially disregarded, and as the liquid overflows from the grooves I (which function as small reservoirs) it flows over the radial surfaces between the bar-like elements in a thin film which attenuates as it moves radially outwardly.

Prior art spray heads have utilised smooth surfaced p distribution drums but in another aspect of this invention the outer surface of the drum has small corrugations

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(machine marks) which further assist in breaking down oversized droplets. Conveniently che corrugations can be on a pitch of about 1/2mm.

o An embodiment of the invention is described hereunder o0 with reference to and as illustrated in the accompanying drawings in which:- Fig. 1 is a front elevation of a spray head; Fig. 2 is a partly sectioned plan taken on line 2-2 of Fig. 1; Fig. 3 is a fragmentary section taken on line 3-3 of Fig. 2 but drawn to a much larger scale; and Fig. 4 is a fragmentary section taken on line 4-4 of Fig. 3 but drawn to an even larger scale.

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A

w In this embodiment, a spray head 10 for forming liquid into droplets comprises a circular shroud 11 which supports mounting brackets 12 extending radially inwardly and supporting a central mounting plate 13 to which is bolted a swash plate piston actuated hydraulic motor 14 of the high speed type, capable of running continuously at about 6,000 rpm.

A rotary distribution drum 16 is coupled by means of a boss 17 to the drive shaft of the motor 14, the boss 17 having drum 16 secured thereto by screw fasteners 18.

The drum 16 is of general cup-like shape, having an end portion 20 and a generally cylindrical portion 21 extending from the end portion 20, the cylindrical portion 21 having a series of slots 22 therein which divide the surface into a series of axially extending bars 23, the radially inner surface of each bar however e* being concave at 24 as best seen in Fig. 3 to thereby form miniature liquid reservoirs which contain a quantity of liquid upon rotation of the drum 16, by centrifugal 20 force.

As can be best seen in Fig. 4, most of the drum 16 is formed from polymeric material, but the mouth end

S

is provided with an annular liquid distribution ring which has a skirt 26 which abuts an inner surface i defines with those surfaces a plurality of conduit spaces i h d 27 from which liquid passes into the reservoirs created by the concave surfaces 24. The concave surfaces 24 extend to the mouth end of the polymeric portion of the drum 16 (for simplicity of moulding) but the ends of the channels thus formed are closed by an annular flange 28 which overlies the mouth end of the polymeric portion of the drum 16.

There is provided a liquid delivery conduit 31 which terminates within the mouth portion of the drum 16 in t a discharge nozzle 32 and this discharge nozzle discharges Ce liquid into an annular groove 33 on the radially inner 0 surface of the skirt 26, and from the groove 33 the liquid ,oe. flows through the conduit spaces 27, and into the reservoir spaces of the concave jrfaces 24 through aligned apertures 34. When the drum is spinning, centrifugal force causes the liquid to lie against the inner wall of the groove 33 as an even thickness film, and it passes evenly therefrom into the reservoir spaces of 0 the conduit spaces 27.

S.

The inner surface of the drum 16 is curved at 36 as shown in Fig. 2 to ensure a smooth flow of any liquid f which inadvertently is retained in the drum when it is

C

stationary.

The intake end of the shroud 11 is provided with i a safety grid 37 and the outlet end surrounds propeller blades 38 projecting from drum 16, the propeller blades 38 terminating at their radially inner ends in ual I t k s R T RC Yro~

I

lugs 39 which, in the plan of the propellor blade 38, diverge towards said radially inner end (see Fig. These lugs 39 are themselves of dovetail shape, which fit into recesses of complementary shape, opening to the periphery of the drum 16.

In addition thereto, the propeller blades are fastened by fastener pins 40. Furthermore, the lugs 39 are overlaid by the flange 28 of the distribution ring Fig. 4 illustrates the manner in which the outer surface 42 of the polymeric portion of drum 16 is corrugate, the 0 corrugations being conveniently formed by a cutting tool, and having a pitch of about 1/2mm. This plays a part in limiting i: development of undersized droplets normally developed by prior art devices, and wasteful because of their tendency to become airborne, and they also reduce the developme.it of oversized droplets which can bcunce off foliage and cito the ground, or even worse, pass directly onto the ground.

For a drum having a diameter of 150mm and spinning at 6,000 rpm, the main ranges of droplet size are likely to be S about 50% between 65 and 85 microns diameter and about between 85 and 160 microns diameter, so that the invention provides a marked improvement over prior art drums and consequently a considerable saving in the expensive agricultural chemicals which are sprayed.

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Claims (5)

1. 2. A spray head according to claim 1 wherein the inner surface of the cup-like drum is curved between the end and cylindrical portions.
2. 4.5555 3. A spray head according to claim 1 or claim 2 wherein a boss extends from a drive shaft on the motor into the cup-like distribution drum, and fasteners secure the boss centrally to the inner surface of its end portion, said boss thereby coupling the distribution drum for drive to the motor. -8- Wr 4. A spray head according to any preceding claim i wherein said drum comprises an annular liquid distribution ring at its mouth, the ring having a skirt which abuts an inner surface of the drum but not the concave surfaces thereof and defines conduit spaces with those concave surfaces, a plurality of apertures extending radially through the skirt and communicating with respective said conduit spaces, surfaces defining a radially outwardly extending and inwardly directed annular groove in the skirt, into which the apertures open, the ring also having a radially outstanding flange which overlies the concave surfaces and thereby closes one end of each said conduit space, j the liquid discharge nozzle being oriented to O• discharge liquid into said annular groove the surfaces of which thereby function as said internal distribution a. surfaces. 6, A spray head according to any preceding claim wherein the outer surface of said drum is corrugated by circumferentially extending corrugations.
3. 6. A spray head according to any preceding claim S further comprising a shroud of generally cylindrical %OQOr shape, said mounting ieans being carried by the shroud, a grid at an air inlet end of the shroud, and propeller blades extending radially outwardly from the drum at an outlet end of the shroud. -9- Aik k B_
4. 7. A spray head according to claim 6 when dependent on claim 4 wherein the radially inner end of each said propeller blade has a lug which, in the cross-section of the propeller blade, is of dovetail shape, and in the plan of the propeller blade diverges towards the radially inner end of the propeller blade, the drum having recesses opening to its periphery which are of complementary shape to and retain the propeller blade lugs, the skirt and flange of the distribution ring engaging surfaces of each propeller blade lug thereby assisting in the retention of that I. lug in its recess. o*
5. 8. A spray head substantially as hereinbefore S."0 described with reference to and as illustrated in the e accompanying drawings. Dated this 14th day of December, 1988. WAIKERIE CO-OPERATIVE PRODUCERS LTD., C By its Patent Attorneys, R.K. MADDERN ASSOCIATES o .s