NZ200795A - Portable sprayer:rotary atomiser & fan within cowl - Google Patents

Description

Priority Date(s): *5.. h.. ^ Complete Specification Filed: Class: H'J'DECW" Publication Date: .... r.....

P.O. Journal. No: N. Z . No.

NEW ZEALAND Patents Act 195 3 COMPLETE SPECIFICATION "SPRAYING APPARATUS." We, MICRONAIR (AERIAL) LIMITED, a British company of Bembridge Fort, Sandown, Isle of Wight do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- - 1 - (Followed by 1A,) 200795 - 1A - "Spraying Apparatus" The invention relates to spraying apparatus for distributing liquids and relates particularly to the low volume distribution of chemical aids to growing crops. Apparatus according to the invention is also suitable for low volume spraying of chemicals for many other purposes, such as for control of tsetse flies, mosquitoes, flies and locusts, and other forms of spraying for public health purposes. The invention provides transportable spraying apparatus which may be transported and used by one person.

New Zealand Patent Specification No. 193050 discloses spraying apparatus comprising a rotary atomiser and an axial fan coupled to the atomiser to form a rotatable unit therewith, the axial fan being situated within a cowl which is shaped aerodynamically to control a blast of air generated by the axial fan when the unit is rotated, whereby, in use, the blast of air passes over the atomiser to disperse the droplets produced thereby. Such an arrangement permits spraying of extremely low volumes of liquid per unit area sprayed, giving substantial savings 200795 in the cost of liquid used, as well as reducing the undesirable contamination of soil and vegetation which is often associated with spraying by conventional apparatus. The present invention provides modifications and developments of the apparatus described and claimed in the above-mentioned patent application.

The earlier patent specification describes spraying apparatus primarily intended for mounting on a vehicle for spraying large areas of crops. There is, however, a requirement for a smaller and lighter spraying apparatus which can be transported and operated by one person and yet, at the same time, will provide the low liquid volume spraying advantages provided by the apparatus of the kind first referred to.

According to the invention there is provided spraying apparatus including a rotatable unit cc^prising a rotary atomiser and an axial fan coupled to the atomiser, the axial fan being situated within a cowl shaped aerodynamically to control a blast of air generated by the axial fan when the unit is rotated whereby, in use, the blast of air passes over the atomiser to disperse the droplets produced thereby, the rotary atomiser comprising a tubular spindle for receiving a liquid to be sprayed, a hollow foraminous atomising cylinder rotatable around the spindle, and a perforate diffuser tube disposed concentrically between the tubular spindle and the foraminous cylinder and rotatable with the foraminous cylinder, drive means for transmitting a rotary drive to the unit, and _ 3 _ 200795 means for supplying to the tubular spindle of thatomiser liquid to be sprayed, the rotatable unit and cowl being mounted at one end of a support arm capable of being transported and used by one person, the drive means also being mounted on the support arm, and a number of elongate vanes being mounted adjacent the internal surface of the diffuser tube and rotatable therewith so as to intercept and effect an initial breaking up of the liquid flow as it passes outwardly from the spindle to the diffuser tube.

The drive means for the unit may comprise an internal combustion engine mounted on the support arm and drivably connected to the rotatable unit by a mechanical transmission. For example, the mechanical transmission may incorporate driving gears and/or a belt drive„ Preferably the internal combustion engine is mounted on the opposite end of the support arm to that on which the rotate.ile unit is mounted.

In alternative arrangements the drive means may comprise an hydraulic or pneumatic motor mounted on the support arm and drivably connected to the rotatable unit, conduits for the supply of hydraulic fluid or air under pressure being mounted on the support arm.

There may be provided in combination with the spraying apparatus a container for liquid to be sprayed and means for supplying liquid under pressure from the container through a liquid supply conduit connected to the rotary atomiser, the container having means enabling it to be transported by the user of the apparatus. For example, the container may be in the form of a knapsack unit to be carried on the back of the user. 2007 95 _ 4 - Alternatively, the container may be mounted on a wheeled trolley which may be transported by one person, the support arm of the apparatus being mounted, preferably adjustably mounted, on the trolley.

In order to supply liquid under pressure from the container, the container may be pressurised. Alternatively the liquid may be delivered from the container by a pump.

The following is a detailed description of 10 embodiments of the invention, reference being made to the accompanying drawings in which: Figure 1 is an axial section through a unit comprising a rotary atomiser and axial fan, Figure 2 is a side elevation of a portable 15 spraying apparatus for use by a single person and incorporating the unit of Figure 1, Figure 3 is a view in the direction of the arrow A of Figure 2, Figure 4 is a section through an alternative, 20 hydraulically driven spraying unit, Figure 5 is a front view of the unit of Figure 4, and Figure 6 is a scrap section on the line A-A of Figure 5.

Referring to Figure 1, the spraying apparatus comprises a rotary atomiser 10 and an axial fan 11 coupled together to form a single rotatable unit.

The atomiser comprises a fixed tubular spindle 200795 12 which is supported on a mounting bar 13 and is provided at one end with a union 14 to which is connected a flexible conduit for supplying the liquid to be sprayed to the interior of the spindle 12. The opposite end of the 5 spindle 12 is closed by an end plug 15 and radial holes 16 are formed in the walls of the spindle 12 adjacent the end plug so that the liquid under pressure may pass radially outwardly of the spindle.

The hub 17 of the axial fan 11 is rotatably 10 mounted on the spindle 12 by means of bearings 18. The hub is formed in two parts 19 and 20 which are held together by screws 21. The cylindrical root ends of three fan blades 22 are clamped in circular sockets formed by cooperating shaped parts of the hub portions 19 and 20, 15 the arrangement being such that the pitch angle of the blades may be adjusted by loosening the screws 21 and separating the hub portions 19 and 20. The blades 22 may then be turned to adjust their pitch whereafter the screws 21 are tightened up again to clamp the blades in their 20 new position. The fan blades may be formed from plastics material, such as "Delrin".

Although three fan blades are shown, any other suitable number of blades may be employed. For example, five blades may be used.

A diffuser tube 23 projects from one face of the hub portion 20 and encircles the end of the tubular spindle 12. The diffuser tube 23 may be formed from stainless steel and has a perforated surface, the perfora- 200795 tions preferably extending over 80$ of the surface of the tube, to allow the liquid passing from the spindle 12 to pass through the diffuser tube. Equally spaced around the internal surface of the diffuser tube 23 are three longitudinally extending vanes 24 each vane lying in a generally radial plane. The vanes are secured at one end to an annular disc 24a which encircles the spindle 12, and at the other end to a disc 24b which is bolted to an end cap 27. The vanes 24 serve to intercept and effect initial breaking up of the liquid as it passes outwardly from the spindle 12 and before it passes through the diffuser tube 23. Although three vanes are shown, any other suitable number may be used, and the vanes may also be of other shapes. For example, the vanes may extend spirally as they extend longitudinally of the diffuser tube.

Encircling the diffuser tube 23 and spaced radially outwardly therefrom is a foraminous atomising cylinder 25, which may be formed from metal gauze. One end of the cylinder 25 is attached to a radially projecting flange 26 on the hub portion 20 and the opposite end is secured to the aforementioned end cap 27.

As shown in Figure 2, the axial fan 11 rotates within the downstream end of a fixed cowl 28 which is supported on the mounting bar 13. The rotary atomiser 10 projects clear of the downstream end of the cowl 28. The cowl may be formed from metal or plastics, such as glass fibre reinforced plastics.

In use the unit comprising the fan 11 and 2 007 9 5 atomiser 10 is rotated by a drive (to be described) and the liquid to be sprayed is delivered under pressure to the interior of the spindle 12. The liquid under pressure passes radially outwardly through the holes 16 in the spindle and is intercepted and broken up into droplets by the vanes 24 before passing through the diffuser tube 23. The droplets continue to move radially outwardly and pass through the gauze atomising cylinder 25 where they are further broken up to form extremely fine droplets. As the droplets pass outwardly through the gauze cylinder 25 they become entrained in the blast of air from the axial fan 11, the blast being controlled and directed by the cowl 28, and the droplets are dispersed as a fine spray over the area towards which the unit is directed. The combination of the particular arrangement of the atomiser and the controlled blast of air causes extremely small volumes of liquid to be dispersed over a very wide area but in a controlled fashion, the dispersion being controlled by the pressure of the liquid and the pitch angle of the axial fan 11.

The atomiser unit described with relation to Figure 1 has many applications and may be used in vehicle mounted spraying apparatus or in other large transportable spraying equipment. However, it is also particularly suitable for use in transportable spraying apparatus suitable for use by one person, since only small volumes of liquid are required to spray large areas and thus the liquid supply may be readily transported by one person. * 200795 - 8 - *• Figures 2 and 3 show one form of portable spraying apparatus incorporating the unit of Figure 1.

Referring to Figure 2, the spraying apparatus comprises a tubular support arm 29 which carries at one end an angled bracket 30 to which is secured the aforementioned mounting bar 13 for supporting the cowl 28 and the tubular spindle 12 of the atomising unit. The hub 17 of the axial fan (the blades of which are removed for clarity in Figure 2) carries a pulley wheel which is encircled by an endless driving belt 31 which passes around a driving pulley 32 rotatably mounted on the end of the support arm 29. The pulley 32 is driven through gearing at one end of a shaft (not shown) which extends longitudinally through the support arm 29 and is coupled to the output shaft of a small internal combustion engine 33 mounted on the end of the support arm 29 remote from the atomiser. The union 14 at the end of the tubular spindle 12 is connected by a variable restricter unit 34 to a flexible conduit 35 which extends along the support arm 29 and is connected, adjacent the engine 33» by a quick disconnect coupling 36 to a flexible hose 37. The hose 37 is connected through a manually adjustable pressure regulator 38 to a knapsack unit 39 comprising a container for the liquid to be sprayed. The container may be pressurised, or a pump may be provided on the knapsack unit for delivering liquid under pressure from the container.

A pressure gauge 40 is mounted on the support 200795 ami 29 and connected to the conduit 35, and the support arm 29 also carries a stand 41 which holds the atomiser clear of the ground when the apparatus is resting on the ground.

The knapsack unit 39 and the support arm 29 are provided with straps, not shown, so that the knapsack unit can be carried on the back of the user while the apparatus itself is slung from one shoulder of the user. The arrangement is such that the main weight of the unit, the engine 33, is close to the body of the user who holds the support arm 29 extending away from him so that the atomiser unit is directed downwardly and forwardly as required to distribute the finely atomised spray.

The straps from which the unit is suspended are preferably so connected to the support arm that the weight of the engine at one end of the arm substantially counterbalances the weight of the atomiser unit at the other end. It will be appreciated however that when the unit is in use there will be a reaction on the end of the support arm due to the air blast from the fan, and the fan is therefore preferably so directed that this reaction also tends to counterbalance the weight of the atomiser unit, making the device lighter to carry and easier to control.

Although the particular device described above is designed to be carried by one person, being supported from the body of the user, other methods of use are possible. For example, the support arm may be mounted, at 2 007 9 5 one end, on a trolley which is light enough to be readily transported by one person, the trolley also carrying the container for the liquid to be sprayed. Preferably the support arm is adjustably mounted on an upper part of the trolley so that the position and orientation of the atomiser unit may be so adjusted that the required spraying pattern is provided alongside the trolley as it is pushed or pulled by the user. The trolley may conveniently be a lightweight metal two-wheeled trolley similar to the kind commonly used as a golf-cart.

In the alternative arrangement shown in Figure 4 a smaller pulley 42 coupled to the hub 17 of the axial fan is driven through the drive belt 31 from a pulley 43 coupled to the output shaft of an hydraulic motor 44. The hydraulic motor 44 is driven in known manner by hydraulic fluid under pressure passing along flexible conduits extending along the support arm 29. The hydraulic fluid may be pressurised by a portable power-driven fluid pump.

In a further alternative arrangement, not shown, the rotary atomiser is driven by a pneumatic motor mounted on the end of the support arm, the motor being provided with air under pressure from any known portable air pump.

In the arrangement of Figures 4 and 5 the mounting bar 13 supporting the atomiser unit and the cowl 28 is connected to the end of the support arm by support stays 45. The ends of the bar 13 are connected to the support stays 45 by adjustable clamping screws 46 so that 200785 K I the bar 13» and hence the cowl and atomising unit, may be tilted with respect to the support stays 45 by loosening the clamping screws 46,adjusting the position of the atomiser and cowl and then retightening the clamping 5 screws. This arrangement is possible using an hydraulic or pneumatic motor since the motor can tilt with the atomiser unit due to the flexibility of the conduits supplying the hydraulic fluid or air under pressure to the motor. This tilting arrangement enables the angle of the cowl and 10 atomiser unit to be adjusted with respect to the support arm as required.

•In tho above doooribod nrrongomontc tho rotating dispersion element of the atomiser is in the form ofjs cylindrical wire gauze. It will be appreciated hawever 15 that other forms of rotating element may be used. Thus the wire gauze cylinder may be replaced by any other form of foraminous cylinder. For exampley/Vae cylinder may be formed from foamed metal which prp^rides a labyrinth path for the liquid as it flows oirb^ardly from the central 20 spindle under centrifugal/iorce. Rotary atomisers employing such a construction are described in British Patent Specification No. 1,486,427. Alternatively, the atomiser may odmprise a plurality of axially spaced rotating dieses, the liquid flowing outwardly over the 25 surfaces of the discs and being dispersed as fine droplets from the outer poriphorico thereof. 200795

Claims (5)

WHAT WE CLAIM IS

1. Spraying apparatus including a rotatable unit comprising a rotary atomiser and an axial fan coupled to the atomiser, the axial fan being situated within a cowl shaped aerodynamically to control a blast of air generated by the axial fan when the "unit is rotated whereby, in use, the blast of air passes over the atomiser to disperse the droplets produced thereby, the rotary atomiser comprising a tubular spindle for receiving a liquid to be sprayed, a hollow foraminous atomising cylinder rotatable around the spindle, and a perforate diffuser tube disposed concentrically between the tubular spindle and the foraminous cylinder and rotatable with the foraminous cylinder, drive means for transmitting a rotary drive to the unit, and means for supplying to the tubular spindle of the atomiser liquid to be sprayed, the rotatable unit and cowl being mounted at one end of a support arm capable of being transported and used by one person, the drive means also being mounted on the support arm, and a number of elongate vanes being mounted adjacent the internal surface of the diffuser tube and rotatable therewith so as to intercept and effect an initial breaking up of the liquid flow as it passes outwardly from the spindle to the diffuser tube.

2. Spraying apparatus according to Claim 1 wherein the drive means for the rotatable unit comprises an internal combustion engine mounted on the support arm and drivably connected to the rotatable unit by a mechanical transmission.

3. Spraying apparatus according to Claim 2, wherein - 13 - 200795 the mechanical transmission incorporates driving gears and/or a belt drive.

4. Spraying apparatus according to Claim 2 or Claim 3, wherein the internal combustion engine is mounted 5 on the opposite end of the support arm to that on which the rotatable unit is mounted.

5. Spraying apparatus according to Claim 1 or Claim 2, wherein the drive means comprise an hydraulic or pneumatic motor mounted on the support arm and drivably 10 connected to the rotatable unit conduits for the supply of hydraulic fluid or air under pressure being mounted on the support arm. 15 MICRONAIR (AERIAL) LIMITED By Their Attorneys HENRY HUGHES LIMITED Per: ./'V • 18 OCTt985