NZ523099A - Frost reduction device - Google Patents

Abstract

A frost inhibiting air acceleration device adapted to inhibit the onset of damage due to frosting conditions in vegetation is comprised of an impeller and an air redirection means. The impeller is actuated to accelerate the air about an area of vegetation and the accelerated air is made to pass through the air redirection means. The inlet face of the impeller can be directed skywards to reduce noise experienced by neighbouring inhabitants. The air redirection means is adapted to enable the exit direction of the air which is passed through the air redirection means to be altered.

Description

Patents Form # 5 52 9 9 INTELLECTUAL PROPERTY OFFICE OF N.Z DEC 2003 RECEIVED NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION AFTER PROVISIONALS # : 523099 / 526007 / 526348 DATED : 10 December 2002 / 20 May 2003/9 June 2003 TITLE : Air Acceleration Device We, Allen Ross Jacobsen Address: 337 Parklands Road, R D 1, Te Awamutu, New Zealand Nationality: A New Zealand citizen 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: PF05.JWP FEE CODE 1050 Air acceleration device INTRODUCTION This invention relates to an air acceleration device and in particular, but not exclusively, to an air acceleration device for use in agricultural and horticultural applications for the purpose 5 of reducing the effects of mild frost conditions on crops.

BACKGROUND Frosts can be particularly harmful to some types of crops, particularly late spring or early autumn frosts, which tend to damage the crops during vital stages of growth. It is possible for a frost to destroy an entire season's production in some crop types, for example kiwifruit 10 and grapes.

During mild frost events in calm weather, an inversion layer typically occurs, with the colder air being situated at ground level, while there is a warmer layer of air at a higher elevation. Over many centuries, a number of methods have been employed to protect crops during periods when frosts are predicted, and some which attempt to draw the warmer inversion 15 layer air down to the crops. Older methods have used the combustion of fuels, in some part to provide heat, but mainly to promote air movement, to interrupt the inversion layer, and draw some of the warmer inversion layer air downwards. In more recent times fans or impellers of various forms have been used to promote the required air movement. Most commonly large diesel motors positioned on the ground, have driven impellers mounted on 20 towers many metres above the ground, via drive-shafts. In some cases helicopters have been used to hover and create the air movement required, or to drive the warmer air down from the inversion layer.

The previous methods have had a number of drawbacks. Firstly the capital costs can be a problem. The machinery is used for a relatively small number of hours per year, but at the 25 same time must be reliable, and operate satisfactorily when it is needed. Cost of maintenance and the cost to have the expensive machinery sitting idle can be significant. Secondly, noise can be a major concern. Frosts by their very nature occur during cold still nights, and are at their worst during the early morning hours. Large fans or impellers can create considerable noise, and this noise can be severe especially the noise generated from 106624NZ-Comp.l 103.doc/PA the inlet face of a large fan or propeller. And any noise generated during the early hours of the morning on a still night can be particularly annoying to neighbouring farmers. Thirdly, operating costs can be significant, it can cost many hundreds of dollars in fuel alone to operate some of the machinery currently available, and often this is due to the inefficient 5 design of the machinery. There may be significant power losses in the drive train, or the aerodynamics of the impeller, or the direction in which the air is moved, which may all may contribute to the inefficiencies and the resulting high energy costs.

Some of the existing frost protection devices are not very effective at providing protection over a wide area. For example some devices draw air directly downwards, or directly 10 upwards, in the hope of producing a steady but low speed movement of air over a wide area. Experience has shown however that these devices provide frost protection over a very limited area.

OBJECT It is therefore an object of the present invention to provide an air acceleration device which is 15 able to overcome some of the above problems, or at least provide the public with a useful choice.

STATEMENTS OF THE INVENTION Accordingly, the invention may broadly be said to consist in an air acceleration device adapted to inhibit the onset of damage due to frosting conditions in vegetation comprising; 20 an impeller, and an air redirection means, wherein the impeller is actuated to accelerate the air about an area of vegetation, and the accelerated air is caused to pass through the air redirection means, and the air redirection means is adapted to enable the exit direction of the air which is passed through the air redirection means to be altered.

The device can be used to delay or eliminate the effects of a frost on a crop by creating a 25 movement of air. The device can be centrally located in the crop, and the air redirection means can be caused to rotate such that the exiting air is redirected across all parts of the crop. 106624NZ-Comp.l 103.doc/PA Preferably the air redirection means changes the direction of movement of the accelerated air from a substantially downward vertical direction to a substantially horizontal direction.

Preferably the air redirection means is a curved duct, for example a curved duct having a bend in it of approximately 90 degrees. However, the air redirection means could of course 5 be a set of vanes or a combination of vanes and a duct.

The curved duct is a particularly useful feature of the device in that the inlet face of the impeller can be arranged to face directly upwards. Much of the noise generated from an impeller originates from the inlet face, so to point it skywards provides the advantage that the noise generated is largely directed skywards, and not towards the neighbouring farms or farm 10 dwellings. While at the same time the device is able to both draw air from above where it is more likely to draw air from the inversion layer, and is able to direct the accelerated air horizontally across a crop to provide a wide area of frost protection. Directing the air horizontally across a crop in a concentrated airflow, and altering the direction of the airflow, has been found to be more effective than to direct the air in all directions at once as with a 15 simple impeller rotating about a vertical axis. A concentrated airflow has improved momentum and will travel further before dissipating.

Preferably the air acceleration device is adapted such that the air redirection means can alter the exit direction through a full 360 degrees about a substantially vertical axis.

Preferably the air redirection means alters the exit direction of the accelerated air by moving 20 in a rotating or an oscillating motion.

Preferably the device is mounted sufficiently high enough to be able to draw air from an inversion layer.

Preferably the device is mounted sufficiently high enough to allow the exiting air to be directed across the top of the vegetation.

Preferably the impeller is actuated by an electric motor. The use of an electric motor is advantageous in that an electric motor can be quieter than a diesel motor, and the energy costs to operate the electric motor can be much less than those to operate a diesel motor of similar power output. 106624NZ-Comp.1103.doc/PA Preferably the impeller is mounted directly onto the output shaft of a motor, for example mounted directly onto the output shaft of an electric motor. This configuration negates the need for any drive train, and therefore reduces cost and improves overall energy efficiency.

Optionally the impeller is driven via a drive train from a motor or engine positioned adjacent 5 to the air acceleration device, for example but not limited to being driven from a "power-take-off' shaft of a farm tractor, or a ground based diesel motor.

Preferably the air acceleration device can be permanently fixed to the ground, or optionally the air acceleration device including any supporting structure can be transportable.

Preferably a transportable version of the air acceleration device is adapted to be transported 10 by a farm tractor, for example, but not limited to, adaptations suitable for the connection of the device to a three-point-linkage system as commonly found on many farm tractors.

Preferably a transportable version of the air acceleration device is adapted to gain some stability from its attachment to a farm tractor.

Preferably a transportable version of the air acceleration device is provided with structure to 15 contact the ground for the purpose of enhancing the stability of the device.

Preferably a transportable version of the air acceleration device is collapsible to reduce the height of the device for transportation purposes, or to manoeuvre the device underneath a crop that is supported on a pergola or similar structure.

Preferably a collapsible version of the air acceleration device is provided with at least one 20 powered actuator to assist with the erection and/or collapsing of the device.

Optionally the air acceleration device includes an extension duct connected to the inlet end of the air redirection means for the purpose of causing air to be drawn from a higher altitude.

Preferably the extension duct has a bell mouth shaped entryway, for the purpose of improving the aerodynamics of the air that is being drawn into the duct, and thereby to 25 improve the efficiency of the device. 106624NZ-Comp.l 103.doc/PA Optionally the air acceleration device is provided with sound reduction materials to reduce the level of noise radiated from the device.

Preferably the curved duct is caused to rotate about a substantially vertical axis, so that the substantially horizontal flow of exiting air can be aimed at a range of horizontal directions.

Preferably the curved duct is caused to rotate about a substantially vertical axis continuously during impeller operation, to provide a full 360 degrees of sweep.

Preferably the duct rotates at a rate of approximately one revolution every five minutes.

Preferably a motor causes the air redirection means to rotate or oscillate.

Optionally the air redirection means is caused to rotate or oscillate by the motor or engine 10 which drives the impeller.

Optionally a wind turbine causes the air redirection means to rotate or oscillate.

Optionally the air redirection means includes an outlet nozzle adapted to further accelerate the air exiting the device. As mentioned above, a concentrated and higher velocity airflow has been found to penetrate further across a crop, and to provide some level of frost 15 protection even hundreds of metres away from the device.

Preferably the impeller is in the form of a propeller or a fan.

Preferably the impeller rotates about a substantially vertical axis.

Preferably a control system automatically turns the frost reduction device on before the onset of frost conditions, and turns it off again when the frost conditions, or the likelihood of frost 20 damage to crops, have passed.

In a second aspect, the invention may broadly be said to consist in a transportable air movement device adapted to inhibit the onset of damage due to frosting conditions in vegetation comprising; an air movement device, and a removable attachment means adapted to attach the transportable air movement device to the three-point-linkage system of a farm 25 tractor. 106624NZ-Comp. 1103.doc/PA Preferably the transportable air movement device includes the features of the air acceleration device substantially as described herein.

Preferably the removable attachment means includes a fitting or fittings adapted to mate with the three-point-linkage system as commonly found on many farm tractors.

Preferably the transportable air movement device includes a means for connection to a power-take-off drive shaft as provided on many farm tractors to provide a power source to operate the air movement device.

Optionally the transportable air movement device includes its own motor or engine to operate the air movement device.

Preferably the transportable air movement device includes means to engage with the ground, the means being adapted to stabilise the device, that is means to reduce the likelihood of the device falling over.

Preferably the transportable air movement device is adapted to gain some stability from its attachment to a tractor. This can produce a significant advantage in that the weight of the 15 tractor provides a substantial stabilising influence to a device which is tall and inherently unstable.

Preferably the transportable air movement device is collapsible to reduce the height of the device for transportation purposes, or to manoeuvre the device underneath a crop that is supported on a pergola or similar structure.

Preferably a collapsible version of the transportable air movement device is provided with at least one powered actuator to assist with erection and/or collapsing of the device.

DESCRIPTION The invention may also broadly be said to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or 25 all combinations of any two or more of the parts, elements or features, and where specific integers are mentioned herein which have known equivalents, such equivalents are incorporated herein as if they were individually set forth. 106624NZ-Comp.1103.doc/PA BRIEF DESCRIPTION OF THE DRAWINGS Preferred forms of the invention will now be described by way of example only with reference to the accompanying drawings in which, 1 is a perspective view of an electric motor driven version of the air acceleration device, 2 is a partial cross sectional view of the electric motor driven version of the air acceleration device, 3 is a side elevation of the upper portion of a transportable version of the air acceleration device, 4 is a side elevation, of the lower portion of the transportable version of the air acceleration device and, is a side elevation showing the transportable version in a folded configuration for transportation. 6 is a side elevation showing an optional lower fold location for the transportable version. 7 is a cross sectional view of an optional curved duct having a bell shaped duct inlet extension.

DETAILED DESCRIPTION Figures 1 and 2 describe a fixed example of the air acceleration device, and Figures 3 to 6 20 describe a transportable example. Figure 7 shows a variation on the curved duct design incorporating an inlet extension.

EXAMPLE 1 With reference to Figures 1 and 2, a fixed air acceleration device (10) is shown comprising at least a propeller (11), and a main motor (13) supported above the ground on a fixed pole 25 (15). The fixed pole (15) is secured in the ground with a concrete foundation (17). Also FIGURE FIGURE FIGURE FIGURE FIGURE FIGURE FIGURE 106624NZ-Comp.l 103.doc/PA supported by the fixed pole (15) is a curved duct (19) and a supporting frame (21) for the curved duct (19). Although a number of motor types can be used it is preferred to use an electric motor for the main motor (13) due to its high power to weight ratio, its quietness of operation and its energy efficiency.

The curved duct (19) and the supporting frame (21) are pivotally attached to the fixed pole (15) by a drive sleeve (23). A bearing plate (25), attached to the drive sleeve (23) bears and slides on a second bearing plate (27) which is attached to the fixed pole (15), thereby supporting the weight of the curved duct (19). Grease can be applied between the bearing plates (25) and (27) to reduce the friction between the two. A geared motor (29) drives the 10 drive sleeve (23), the supporting frame (21) and the curved duct (19) about the axis of the fixed pole (15), via a gear train (31).

A controller (33) detects the conditions that are likely to produce frost damage in a crop, and automatically supplies power to the main motor (13) and the geared motor (29) via electrical cabling (35). The main motor (13) turns the propeller (11). The propeller (11) is oriented to 15 draw air from above the device and to pass it through the curved duct (19). The resulting substantially horizontal air flow (37) is directed across a crop for example.

The operation of the geared motor (29) to turn the curved duct (19) about the axis of the fixed pole (15) provides for a full 360 degrees of influence of the air acceleration device (10) about its location. When the conditions that are likely to cause frost damage to a crop have 20 passed, the controller (33) can automatically switched off the air acceleration device (10).

Such a device (10) can be used to provide frost protection for an orchard of kiwifruit or a vineyard of approximately 10 acres using a 10 kilowatt electric motor, and a fan of 1.8 metres diameter. The device has significant advantages over existing frost fans. The electric motor (13) is very reliable, and cheap to run as well as being quieter than many diesel 25 engines. Having the front face of the fan (11) pointing upwards is a great advantage in reducing noise. Much of the noise produced by the fan (11) is directed upwards, and this causes less disturbance to neighbours.

The curved duct (19) can direct the air in a horizontal direction, and by simply rotating the duct (19) about a vertical axis, the accelerated air can be directed through a full 360 degrees. 106624NZ-Comp.1103.doc/PA This range of output is achieved without having to move the motor, providing another advantage whereby the supply of energy to the motor does not have to travel through a swivel joint or brushes of any sort, reducing cost and complexity and improving reliability.

The curved duct (19) can have a narrowed or constricted outlet which can further concentrate 5 and accelerate the air passing through the device. The inventor has seen considerable advantage in being able to direct the air through an outlet nozzle which to some extent concentrates the outlet air into a relatively narrow but higher velocity airflow. The advantage being that the higher velocity airflow will travel a greater distance before dispersing, and therefore allow a larger crop area to be protected.

An earlier prototype produced by the inventor had a propeller and motor assembly rotating about a horizontal axis, which was particularly noisy especially when the propeller was facing a listener. It was found that mounting the propeller to rotate about a vertical axis produced a quieter operation, in that the most disturbing noise was directed towards the sky.

The inventor also found that because the electric motor was smaller and lighter than a 15 comparable diesel motor, it was simpler to mount in an elevated position. Additionally an electric motor was found to be advantageous because automatic start-up was almost guaranteed in an electric motor, but this was not so with an internal combustion engine. Similarly the electric motor requires less maintenance than an equivalent diesel engine, used in this application.

A second prototype produced by the inventor used an electric motor and propeller oriented with a vertical axis of rotation and mounted directly above and blowing onto a modified conical shape, the apex of the conical shape facing the propeller, and the conical shape having concave curved sides. The modified conical shape was intended to re-direct the downward flowing air into a horizontal flow in all directions at the same time. But it was 25 found that the effect of the air movement was soon dissipated and only a small area of crop was influenced by the device.

EXAMPLE 2 With reference to Figure 3, a transportable air acceleration device (50), which can also be referred to as a transportable air movement device, is shown comprising at least a propeller 106624NZ-Comp.1103.doc/PA (11) and a curved duct (19). The duct (19) is mounted on a structure (51). The structure includes a lower member (53) and an upper member (55). The upper member (55) is pivotally attached to the lower member (53) by the pivot arrangement (57). A hydraulic ram (59) is used to assist the movement of the upper member (55) from an erect position as 5 shown, to a lowered position for transportation. This transportation configuration is shown in Figure 5.

With reference to Figure 4, the lower member (53) includes a main upright (61), a base (63), and a mounting structure (65). The mounting structure (65) includes mounting points (67) which are adapted to mate with a typical three point linkage system found on many farm 10 tractors. The ability to connect with the three point linkage system of a tractor produces a number of advantages, firstly, the device can easily be lifted and transported, and also, the weight of the tractor can provide a heavy anchor to stabilise the device when erected and operating. The base (63) includes feet (69) to improve the stability of the transportable air acceleration device (50) when it is operating.

An input shaft (71) is adapted to receive a drive-shaft which is powered by a ground based engine, for example, a tractor, utilising the tractor's power take off system. A right angle gearbox (73) transfers the torque to a vertical telescoping drive-shaft (73). The torque is further transferred through a flexible coupling (75) to another shaft (77) which is mounted inside the upper member (55) and transmits the torque to the propeller (not shown).

The transportable or tractor mounted version described above has arisen out of a need to produce a machine that can easily be transported from one location in an orchard to another, or indeed from one orchard to another.

With reference to figure 5, the transportable air acceleration device (50) is shown in a transportation configuration. Since the device needs to be of some height to be effective, it 25 can not easily be transported along the road, or underneath power lines etc, in a fully extended configuration.

By the action of the hydraulic ram (59) the upper member (55) can be rotated about the pivot (57) to a lowered position. Conversely the hydraulic ram (59) can be used to raise the upper member (55) to a vertical position for use as an air acceleration device (50). 106624NZ-Comp.1103.doc/PA The entire device (50) can be attached to a tractor using the mounting points (67) and then lifted and transported. The mounting points (67) are adapted to enable the device (50) to be connected to the three point linkage system of a farm tractor. This linkage to the farm tractor can also be used to stabilise the device (50) when in use.

With reference to figure 6, a variation on the transportable air acceleration device (50) is shown. In a number of orchard situations the vines are grown on a very large pergola, and the only way to get a piece of machinery into the centre of the orchard is to drive underneath the pergola. To achieve this it is necessary to further reduce the height of the device (50) to a height in the range of 1.5 to 2 metres.

To achieve this the lower member (53) of figure 4 is divided into two, a base member (83) and an intermediate member (81), which are connected about a pivot (84). A second hydraulic ram (85) can be used to raise and lower the intermediate member (85), for example from a substantially horizontal stowed position for travel under a pergola, to an upright position for use.

Similarly the telescoping drive-shaft (73) of figure 4 can be divided into two shafts (87) and (89), which can be provided with a coupling that connects when the two shafts (87) and (89) are aligned and mated.

With reference to figure 7, a variation on the curved duct (19) is shown. In this case the curved duct (19) has a bell mouth shaped duct extension (91) forming the inlet to the duct.

The bell mouth shaped duct extension (91) can be used to improve aerodynamic efficiency, and/or to extend the inlet higher for the purpose of drawing the warmer air down from the inversion layer which may exist on a calm frosty night. 106624NZ-Comp. 1103.doc/PA

Claims (18)

1. A frost inhibiting air acceleration device adapted to inhibit the onset of damage due to frosting conditions in vegetation comprising; an impeller, and an air redirection means, wherein the impeller is actuated to accelerate the air about an area of vegetation, and 5 the accelerated air is caused to pass through the air redirection means, and the air redirection means is adapted to enable the exit direction of the air which is passed through the air redirection means to be altered.

2. A frost inhibiting air acceleration device as claimed in claim 1, wherein the air redirection means changes the direction of movement of the accelerated air from a 10 substantially downward vertical direction to a substantially horizontal direction.

3. A frost inhibiting air acceleration device as claimed in any preceding claim, wherein the air redirection means is a curved duct, for example a curved duct having a bend in it of approximately 90 degrees.

4. A frost inhibiting air acceleration device as claimed in any preceding claim, wherein 15 the air acceleration device is adapted such that the air redirection means can alter the exit direction through a full 360 degrees about a substantially vertical axis.

5. A frost inhibiting air acceleration device as claimed in any preceding claim, wherein the impeller is actuated by an electric motor.

6. A frost inhibiting air acceleration device as claimed in any preceding claim, wherein 20 the impeller is mounted directly onto the output shaft of a motor, for example mounted directly onto the output shaft of an electric motor.

7. A frost inhibiting air acceleration device as claimed in claims 1 to 4, wherein the impeller is driven via a drive train from a motor or engine positioned adjacent to the air acceleration device, for example but not limited to being driven from a "power-take- 25 off' shaft of a farm tractor, or a ground based diesel motor.

8. A frost inhibiting air acceleration device as claimed in any preceding claim, wherein the air acceleration device is adapted to be permanently fixed to the ground. 106624NZ-RvsdClms.0505.doc/PA INTELLECTUAL PROPEFiT' ' ' ' ' 1 9 MAY 2005 RPrcu/cn - 14-

9. A frost inhibiting air acceleration device as claimed in claims 1 to 7, wherein the air acceleration device is adapted to be transportable.

10. A frost inhibiting air acceleration device as claimed in claim 9, wherein the transportable version of the air acceleration device is adapted to be transportable by a 5 farm tractor, for example, but not limited to, adaptations suitable for the connection of the device to a three-point-linkage system as found on farm tractors.

11. A frost inhibiting air acceleration device as claimed in claims 9 or 10, wherein the transportable version of the air acceleration device is collapsible to reduce the height of the device for transportation purposes, or to manoeuvre the device underneath a crop 10 that is supported on a pergola.

12. A frost inhibiting air acceleration device as claimed in any preceding claim, wherein the air acceleration device includes an extension duct which has a bell mouth shaped entryway.

13. A frost inhibiting air acceleration device as claimed in any of claims 3 to 12, wherein 15 the curved duct is caused to rotate about a substantially vertical axis, so that the substantially horizontal flow of exiting air can be aimed at a range of horizontal directions.

14. A frost inhibiting air acceleration device as claimed in any preceding claim, wherein the impeller is in the form of a propeller or a fan. 20

15. A frost inhibiting air acceleration device as claimed in any preceding claim, wherein the device further incorporates a control system which is adapted to automatically turn the device on before the onset of frost conditions, and turns it off again when the frost conditions, or the likelihood of frost damage to crops, have passed.

16. A frost inhibiting air acceleration device substantially as described herein with 25 reference to figures 1 and 2 of the accompanying drawings.

17. A frost inhibiting air acceleration device substantially as described herein with reference to figures 3 to 6 of the accompanying drawings. 106624NZ-RvsdClms.0505.doc/PA INTELLECTUAL PROPER!'. — "'.2 I ! 1 9 MAY 2005 j R EC E!\/ L O 1 -15-

18. A frost inhibiting air acceleration device substantially as described herein with reference to any of the accompanying drawings PIPERS Attorneys for: ROGER MELVYN JUNIOR COSTAIN AND VICTORIA LEE COSTAIN as trustees of the RMJ and VL Costain Family Trust SND OF CLAIMS