AU707980B3

AU707980B3 - Agricultural heating control method

Info

Publication number: AU707980B3
Application number: AU69051/98A
Authority: AU
Inventors: Florencio Lazo B
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-05-29
Filing date: 1998-05-29
Publication date: 1999-07-22
Anticipated expiration: 2004-05-29

Description

/IUU/UIZ 28/5/91 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE

SPECIFICATION

PETTY PATENT Invention Title: AGRICULTURAL HEATING CONTROL METHOD The following statement is a full description of this invention, including the best method of performing it known to me:- AGRICULTURAL HEATING CONTROL METHOD DESCRIPTION OF THE INVENTION The present invention is related to a method and apparatus for frost control in agricultural crops and orchards and alternatively for evaporating the rainwater from the crops.

It is well known that the problems generated by frost over crops are unlike drought and pests etc, in that deterioration over them is not cumulative.

Depending on the frost and on the crop, one frost is able to destroy the entire crop.

There are two different types of frost: radiative frost and advective freeze.

Radiation frost consist in a descent of the temperature in the air layer close to the surface of the earth, due to the temperature losses, because of the heat radiated by the earth. In this case, the air starts cooling from the bottom to the top, generating the phenomenon called "inversion layer", that is to say, the temperature gradient diminishes as the air is closer to the ground. This inversion layer could be of about 60 mts. thick or a height of about 60 mts. At the middle of it the temperature could be 50C higher than the temperature at the ground level. In this inversion layer, the 10 mts closer to the ground are at a temperature which can cause frost damage.

The advective freeze is generated when a cold air mass spreads over the area at a high altitude. In this case, the cooling of the air layer is from the top to the bottom, in a way in which the temperature gradient goes up as the air is closer to the ground.

The most frequent is radiation frost, which can be a daily cyclical phenomenon during the cold seasons.

Different methods have been used to fight the effects of the frost. The most simple is the use of hot houses, but it is very expensive and difficult to manage for a large area, and also humidity can cause very bad effects in some crops.

Another method is to burn different kinds of fuels, liquid or solid, in different points of the treated area. This is very expensive because it is very inefficient, due to the fact that the temperature gradient between the point of

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ignition and the air treated is very high. Further, the heated air rises very fast, and does not irradiate the heat to the surrounding air. (Chimney effect).

With the development of new irrigation techniques, sprinklers are being used to wet the crop we want to protect. But the problem now is that in some cases it is not convenient to wet the crop or the trees, for potential fungal diseases or in some cases there will be insufficient water at this time of the year (Spring time).

Another method consists in blowing warm air over the cold air which is located over the orchard or vineyard. To do this helicopters or wind machines are used, which blow the warmer air from the inversion layer constantly, and is obviously a very expensive method.

Also there is a last group of methods to fight the effects of the frost, consisting in the use of axial fans, mobile or stationery, equipped with heaters, which takes the surrounding air, heats it and blows it. This group of methods, are of a short range, related with the power used, and the results are not satisfactory. In this group is the machine described in the Chilean Patent Application No. 682-94 abandoned and the one described in the Russian magazine "Traktory-i- Sel skohosyainestevennye- Mashiny". This machine is in two versions, one stationary, YOP-2 and the mobile YOP-2M. The YOP-2 is a stationary machine mounted over a tower and blows the hot air through a rotator tube, 1 meter in diameter, and covers an area of 400mts, and is particularly useful for the advection freeze. The YOP-2M is mounted over a cart and produces fog which is blowed over the field, using 90 to 100 MT of water per Ha.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method and/or device which is more effective in the control of frosts, or evaporation of rain. With this object in mind the present invention provides in one aspect a method for frost control in agriculture and fruiticulture, and/or for evaporating the rainwater from the plantations and orchards, including the following steps: a) taking the cold air from the ground level and warming it up to reach a temperature of 80 0 C to 100 0

C.

b) Imparting a large kinetic energy to the air warmed in step a) to expel it at >1: a speed of approximately 200 km per hour.

c) Reduce the turbulence in the air conditioned in the before mentioned steps.

d) Blow over the ground the air conditioned in the beforementioned steps, horizontally, and at a hight similar to the one the machine took the cold air in the beforementioned step moving over the soil at a speed of approximately 6 to 10 Km. per hour, at intervals of approximately ten minutes.

Despite the simplicity of the invention, it is based in the control of some parameters, which together, proved being absolutely different in its results with the achievements obtained to this time by the prior art. The control of the parameters is basically achieved by: a) Taking the air at the ground level b) Blowing the air in a relatively laminar flow c) Blowing the air at a speed of approximately 200 Km. per hour at the exit of the apparatus, which means that the air reaches a long distance.

The beforementioned conditions, used in the method and executed by the apparatus of the invention, allows the introduction of a wedge of hot air in the base of the inversion layer which is causing the frost (radiative frost) or allows the artificial creation of an inversion layer at the ground level (advective freeze). Fig 2 and 3.

It has been discovered, surprisingly, that for achieving the characteristics b and c, beforementioned, a centrifugal fan is required, as it produces a less turbulent stream of air at the exit than an axial fan, and imparts a very large kinetic energy to the air expelled.

Another application of the invention is related with evaporating the rainwater from crops which are sensitive, like Cherries, Grapes etc. The invention has proved to be very effective for removing the water very fast and avoiding damage to the crops.

For a better understanding of the invention, it will be described over a preferred embodiment, which will not be considered as limitative, and with reference to the figures and drawings, in which i" Fig 1. represents an schematic graphic typical of the distribution of the temperatures with altitude, for radiation frost. The continuous curve represents temperature distribution without the intervention of the invention, instead the segmented curve represents temperature distribution achieved with the intervention of the invention.

Fig 2. represents an schematic graphic typical of the temperature distribution with altitude, for the advective freeze. Symbols similar to Fig 1.

Fig 3. represents an schematic graphic typical of temperature distribution of the stream of hot air blown from the apparatus invented, as long as it travels horizontally from the apparatus exit.

Fig 4. is an elevation view of a preferred construction of the apparatus invented, which apply the beforementioned method.

Fig 5. is a side view of the right hand side of the apparatus.

Fig 6. is a parallel perspective of the apparatus on Fig 4, from an angle.

Fig 7. shows a view of the apparatus, from an angle similar to the one on Fig 6, installed in an agricultural tractor, with the fuel tanks (Propane), in the case the invention uses heaters consisting in bumers of liquid gas.

The method for frost control or for evaporating the rainwater over the crops, according to a preferred aspect of the present invention, consists basically in taking the ambient air from the ground level and transforms it as follows: if a) Heat the air from the ambient temperature (approx 30C 0°C) to a temperature between 800C to 1000C.

b) Put kinetic energy on the hot air to expel it at a speed of approximately 200 km. per hour.

c) Reduce the turbulence acquired by the air during the process of raising the kinetic energy, in a way that when it is blown to the crop, it is not dissipated by the turbulence and reaches a long distance.

d) Distribute over the ground streams of the air conditioned in the beforementioned steps, blowing it horizontally, and at an altitude similar to the one the apparatus took the cold air from; and travelling over the ground at a speed between 6 to 10 Km. per hour, at intervals of approximately ten minutes.

The suction, conditioning and blowing of the air, is executed in movement, for example pulling the apparatus at a speed between 6 to 10 Km.

per hour with the help of a tractor vehicle.

The sequence of these three simple operations can change, depending on the priorities. These priorities are related with efficiency and safety, especially if the heaters are burners.

If efficiency is preferred over safety, firstly raise the kinetic energy and then heat the air. This order in the sequence is more efficient because it is easier to raise the kinetic energy of a dense gas (cold air) in comparison with a light gas. The inconvenience of the sequence is when heaters like burners are used at the exits of the apparatus, and can blow flames which could injure people or damage the crops.

If safety is preferred over efficiency, when heaters like burners are used, firstly heat the cold air and then raise the kinetic energy, flames will be produced in the interior of the device executing the invented method.

In either case, the global efficiency of the method is by far much better than the prior art, thanks to the reduced turbulence of the stream of hot air conditioned in the heating step and raising the kinetic energy step.

The three beforementioned operations are executed by means of an apparatus like that shown in Figs 4 to 7. The apparatus basically consists of a centrifugal fan 1 with an axial air entrance 2 and two tangential exits 3 oriented in an opposite way between them. These exits 3 are represented in a vertical plane, and with the axial entrance 2 in an horizontal position. But, the exits 3 could be in an horizontal way and with the entrance 2 in a vertical position. The burners 4 are represented at the entrance of the cold air 2, according with the option, safety over efficiency.

The apparatus invented can be mounted over a cart 5, for pulling or an autocart, oriented in a way in which the exits 3 are transversal to the movement of the apparatus, blowing the air to both sides of the apparatus, in a horizontal plane and close to the ground level.

Fig 1. represents with a continuous line the temperature distribution with

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altitude, for the radiation frost. It shows that in the first 5 mts. close to the ground, the temperature is between -3oC and 0oC, going warmer to the 20 mts. level where it reaches the maximum, about 50C, and it goes down in a way in which at 50 mts it is about 000C. The segmented line represents the temperature distribution with the help of the invention, affecting basically the first 20 mts.

staying this portion at a temperature of about 40C to 50C. In reality, the invented method affects basically the first 10 mts. but being in this case a radiation frost, the ambient air between 10 to 20 mts is at 30C to Fig 2 represent with a continuous line temperature distribution with altitude for the advective freeze. It shows that temperatures descend with altitude, reaching a maximum temperature at the ground level, about -30C. The segmented line represents the distribution of the temperature with the help of the invention, changing the temperatures in the first 10 mts. to positive values.

As we can see in figures 1 and 2, the invented method allows the temperature at ground level to be raised, and shows a very interesting phenomenon: in the case of the inversion layer (radiative frost), the invention neutralises the inversion and gives a temperature distribution decreasing with height, and for the advective freeze, the invention generates an inversion layer.

The hot air is projected horizontally by the exits 3 of the apparatus, at a temperature between 800C and 1000C. This stream of hot air maintains its horizontal direction due to the fact that it loses very rapidly its caloric energy, as it is represented on figure 3. As it diminishes the temperature with the horizontal distance, the hot air diminishes it speed, in a way in which the density is maintained relatively uniform, preventing the air from going up. This result is a key in the success of the invented method and the apparatus, because, and differently from other ideas, practically all the heat is distributed over the ambient air layer which is desirable to maintain at a good temperature.

Some examples of the use of the invented method and apparatus are described, using burners of liquid gas as fuel, contained in four cylinders of kg. each, giving an operating time of approximately 5 hours.

Example 1 The method was applied in three blocks of vineyards, 5 Ha. each with roads in between and the sides of each one. With a tractor the invented apparatus was carried over the road surrounding the central block, blowing air to both sides, the temperature in the blocks was raised 0.5°C at a distance of mts., this temperature began to go down because of the normal radiation losses, then it was necessary to pass again every approximately 10 minutes. The area controlled by the apparatus is about 50 mts to each side of the apparatus, forming a horizontal bag of hot air which is pushed in every pass of the apparatus. This artificial microclimate maintains a temperature of about 0.3°C in the coldest part to 1.2°C in the warmest part. In the area not affected by the apparatus, the ambient temperature was Example 2 The method was carried out in a 15 Ha. Plum orchard, Red Beaut variety, divided in two blocks, 7.5 Ha each and with a road between the two blocks. In the 1996 season this orchard was severely damaged by the September 6th frost, we had estimated 30,000 boxes and with the frost damage we got only 214 boxes.

In this case the apparatus was passed only by the central road, blowing air to both sides of the road. Using very precise thermometers it was settled that at a distance of 120 mts. the temperature was raised 0.3°C, which descended in about ten minutes. It Was possible'to maintain'the orchard temperature at about passing regularly each ten minutes, while the ambient temperature was -1.90C.

Claims

1. A device for frost control in agriculture and fruticulture and/or for evaporating the rainfall from the plantations and orchards, including a centrifugal fan with an axial entrance for the air, said device being mounted in a cart or autocart, oriented such that the exit of air will be transversal to the movement of the cart, air flow is substantially laminar and horizontal, and the speed of the air exiting the device is between 180 and 220 km/hr, and wherein said centrifigal fan is equipped with heaters to raise the temperature of the air to reach between 800 C and 1000 C.

2. A device as claimed in claim 1, further including two exits tangentially oriented and opposed.

3. A device as claimed in claim 1 or claim 2, wherein said centrifugal fan is oriented in a vertical or horizontal position. DATED this 26th day of May, 1999 FLORENCIO LAZO B WATERMARK PATENT TRADEMARK ATTORNEYS 4TH FLOOR, "DURACK CENTRE" 263 ADELAIDE TERRACE PERTH W.A. 6000 AUSTRALIA