GB2118460A - Liquid spray apparatus - Google Patents

Abstract

In a crop spraying system a liquid spray comprises two concentric annular ducts (10,12) leading to two concentric annular spraying nozzles (18,20). Means are provided in each duct for obturating and varying the flow of liquid therethrough. An intermediate sleeve (24) is formed on both its inner and outer surfaces with three axial channels (32,34 and 132,134) which define flow ducts. A rotatable plate (54) provided with six apertures is indexable to regulate the number of inner ducts in use. A similar plate (64) regulates the outer ducts. <IMAGE>

Description

SPECIFICATION Liquid spray apparatus This invention relates to liquid spray apparatus and particularly but not exclusively to liquid spray apparatus for agricultural crops which utilises an electrostatic liquid spraying system.

In such systems a suitable liquid, such as a pesticide or a herbicide, is sprayed on to the crops from a moving vehicle, such as an agricultural tractor, and the electrostatic spraying system minimises the quantity of liquid used as well as ensuring that the crops are thoroughly coated on top and underneath with the liquid. This is achieved by making the liquid impinge on a conducting surface which has an earthed field intensifying electrode mounted adjacent thereto. When the conductive surface is electrically charged to a potential of the order of 1-20 kilovolts, an electrostatic field is formed at the surface which causes the liquid droplets to atomize on hitting the surface and form electrically charged particles. These are projected away from the conducting surface and the electrode towards the surfaces of the crops which have, of course, earth potential.

It is an object of the present invention to provide liquid spray apparatus which will enable the rate of flow of the liquid to be varied considerably or which will enable two or more different liquids to be sprayed simultaneously.

According to the present invention liquid spray apparatus comprises at least two concentric annular ducts each leading to one of at least two concentric annular spraying nozzles, means being provided in each duct for obturating and varying the flow of liquid therethrough.

Preferably only two concentric annular ducts are provided.

Each annular duct may comprise a plurality of separate channels which may be straight or helical.

The means for obturating and varying the flow of liquid through each annular duct preferably comprises a plate which is rotatably mounted relative to the plurality of separate channels in each duct as described and claimed in our co-pending patent application No; 8133077.

The spray apparatus preferably comprises a central member, an intermediate sleeve and an outer sleeve arranged concentrically, the central member being rotatable relative to the intermediate sleeve to obturate or vary the flow of liquid therebetween, and the intermediate sleeve and the outer sleeve being relatively rotatable to obturate or vary the flow of liquid therebetween.

Preferably the outer sleeve is fixed.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which Figure lisa cross-sectional view through liquid spray apparatus in accordance with the invention along the line 1-1 Figure 4, Figure 2 is a cross-sectional view through the apparatus along the line 2-2 in Figure 1, Figure 3 is a cross-sectional view through the apparatus along the line 3-3 in Figure 1 and Figure 4 is a cross-sectional view through the apparatus along the line 4-4 in Figure 1.

As shown in Figure 1, the spray apparatus com prises basically three elongate members forming two liquid supply ducts 10, 12, leading to two conical spray ducts 14,16 each having a circular restricted nozzle 18,20.

The three elongate members consist of an outer fixed circular sleeve 22, an inner circular sleeve 24 and a circular shaft 26. The shaft 26 has a conical disc 28 formed as its end, the inner sleeve has a conical flared portion 30 at its end and the outer sleeve has a conical cover 52 formed at its end. The three members are spaced apart concentrically by projections formed on the inner and outer surfaces of the inner sleeve 24, these projections dividing the inner liquid supply duct 12 into three separate equally spaced axially extending channels 32,34 and 36 and the outer liquid supply duct 10 also into three separate equally spaced axially extending channels 132,134 and 136.

Secured to the upper end of the shaft 26 and abutting the ends of the channels 32,34 and 36 is a plate 54 with six orifices 40,42,44,46,48 and 50 formed therein. These orifices are positioned such that by rotating the shaft 26 relative to the inner sleeve 24 none, one, two or all of the channels 32,34 and 36 can be aligned with an orifice as described in our co-pending patent application No: 8133077. The plate 54 is urged into contact with the upper ends of the channels 32, 34 and 36 by a spring 56, the other end of the spring abutting an index plate 58 which is prevented from movement with the shaft 26 by projections engaging slots 59 formed in the inner sleeve 24. The slots 59 permit the index plate 58 to move axially relative to the inner sleeve 24.On the surface of the index plate 58 is formed a number of curved projections 60 and these are adapted to engage in curved recesses formed in the surface of a reaction plate 62 secured to the shaft 26. Thus as the shaft 26 is rotated the reaction plate 62 rotates and the index plate 58 is moved axially against the spring 56 by the projections 60. The index plate 58 and the reaction plate 62 therefore act as a lock to secure the shaft 26 in a number of desired positions within the inner sleeve 24.

A similar arrangement is employed at the upper ends of the channels 132,134 and 136. A plate 64 having six orifices 140,142,144,146, 148 and 150 abuts the upper ends of the channels 132, 134 and 136 and the plate 64 is secured to the outer fixed sleeve 22. Thus relative rotation is achieved between the plate 64 and the channels 132, 134 and 136 when the inner sleeve 24 is rotated. A spring 66 abuts the plate 64 and acts on an index plate 68 which is secured to the inner sleeve 24. The index plate 68 has a number of curved projections 70 (as on the index plate 58) and these are adapted to engage in curved recesses formed in the surface of a reaction plate 72 secured to the outer sleeve 22. Thus as the inner sleeve 22 is rotated the index plate 68 rotates and is moved axially (together with the inner sleeve 24) against the spring 66 by the projections 70.As before, the index plate 68 and the reaction plate 72 act as a lock to secure the inner sleeve 24 in a number of desired positions within the outer sleeve 22.

Liquid is fed to the spray apparatus to the upper ends of the inner sleeve 24 and the outer sleeve 22, suitable holes being provided in the index plates 58 and 68 to permit the liquid to pass through to the plates 54 and 64. The flow of liquid can be adjusted independently from zero to all three of the channels 32,34 and 36 and the channels 132, 134 and 136, Figures 2 and 3 showing the channel 132 open only and the channels 132 and 134 open by suitable positioning of the plates 54 and 64. Thus the same liquid can be supplied to the two sets of channels and the flow varied from a rate of one channel to six channels, or two separate liquids can be supplied to the two sets of channels. This is particularly suitable fortwo liquids which require to be sprayed simultaneously but will not mix together.Alternatively a supply of pressurised air can be supplied to one of the sleeves with or without the channels to assist the spray issuing from the lower end of the apparatus.

It will be seen that fewer or more than the three channels shown can be provided and three or more concentric sets of channels may be used.

It is intended that the liquid is sprayed from the restricted nozzles 18 and 20 and the apparatus is particularly suitable for use in an electrostatic spraying system. Thus the disc 28 and the conical flared portion 30 can be made of a conducting material and electrically charged to a potential of 1 to 20 kilovolts whilst an earthed intensifying electrode (not shown) is formed around or within the cover 52.

The liquid droplets are atomised when they hit the surface of the disc 14 or the surface of the conical flared portion 30 and atomisation is achieved to a high order by the electrostatic forces.

CLAIMS (Filed on 29.10.82.) 1. Liquid spray apparatus comprising at least two concentric annular ducts each leading to one of at least two concentric annular spraying nozzles, means being provided in each duct for obturating and varying the flow of liquid therethrough.

2. Liquid spray apparatus constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. act as a lock to secure the inner sleeve 24 in a number of desired positions within the outer sleeve 22. Liquid is fed to the spray apparatus to the upper ends of the inner sleeve 24 and the outer sleeve 22, suitable holes being provided in the index plates 58 and 68 to permit the liquid to pass through to the plates 54 and 64. The flow of liquid can be adjusted independently from zero to all three of the channels 32,34 and 36 and the channels 132, 134 and 136, Figures 2 and 3 showing the channel 132 open only and the channels 132 and 134 open by suitable positioning of the plates 54 and 64. Thus the same liquid can be supplied to the two sets of channels and the flow varied from a rate of one channel to six channels, or two separate liquids can be supplied to the two sets of channels. This is particularly suitable fortwo liquids which require to be sprayed simultaneously but will not mix together.Alternatively a supply of pressurised air can be supplied to one of the sleeves with or without the channels to assist the spray issuing from the lower end of the apparatus. It will be seen that fewer or more than the three channels shown can be provided and three or more concentric sets of channels may be used. It is intended that the liquid is sprayed from the restricted nozzles 18 and 20 and the apparatus is particularly suitable for use in an electrostatic spraying system. Thus the disc 28 and the conical flared portion 30 can be made of a conducting material and electrically charged to a potential of 1 to 20 kilovolts whilst an earthed intensifying electrode (not shown) is formed around or within the cover 52. The liquid droplets are atomised when they hit the surface of the disc 14 or the surface of the conical flared portion 30 and atomisation is achieved to a high order by the electrostatic forces. CLAIMS (Filed on 29.10.82.)

1. Liquid spray apparatus comprising at least two concentric annular ducts each leading to one of at least two concentric annular spraying nozzles, means being provided in each duct for obturating and varying the flow of liquid therethrough.

2. Liquid spray apparatus constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.