GB2372687A

GB2372687A - Apparatus for controlling vegetation by burning

Info

Publication number: GB2372687A
Application number: GB0104924A
Authority: GB
Inventors: Stuart Franklyn Goodinson
Original assignee: GREEN DRAGON FLAMING Ltd
Current assignee: GREEN DRAGON FLAMING Ltd
Priority date: 2001-02-28
Filing date: 2001-02-28
Publication date: 2002-09-04
Anticipated expiration: 2021-02-28
Also published as: GB2372687B; GB0104924D0

Abstract

An apparatus for controlling vegetation by burning comprises a mounting frame (A) for attachment to a vehicle, a tank (1), for storage of a liquefied petroleum gas, mounted on the mounting frame (A), a boom assembly (B) demountable on the mounting frame (A), and a plurality of burner assemblies (19) secured in lateral disposition on the boom assembly (B). Liquid from the liquefied petroleum gas in the tank (1) is controllably supplied through a main line (7) at a high pressure. Gas from the liquefied petroleum gas in the tank (1) is controllably supplied through a pilot line (14) at a lower pressure. The main line (7) and via quick connect hose (13) and/or the pilot line (14) is selectively connected to the burner assemblies 19 on the boom assembly (B) for operation. Figure 4 shows an embodiment where only the pilot line is connected to burner assemblies 26. The boom may be configured as an inter-row assembly.

Description

APPARATUS FOR CONTROLLING VEGETATION BY BURNING

The present invention relates to apparatus for controlling vegetation by burning.

It is known to provide apparatus mounted on a vehicle, such as a tractor or trailer and used to control vegetation by means of heat produced by burning a liquefied petroleum gas (LPG), such as propane. The heat vaporises water in cells of plants causing cells to rupture, thereby destroying the ability of treated plants to move water and photosynthesise and resulting in death of such plants.

The procedure is applicable to provide a concentrated blanket of heat from burners, such as for general overall weed control or for desiccation of haulm of crops, such as potatoes.

Alternatively, the procedure is applicable to provide weed control between rows of crops, using appropriately spaced-apart burners.

A problem exists in that different burners are required for each of these two functions of the apparatus. The burners used to provide the concentrated blanket of heat

each have a high heat output and operate from a high pressure of liquefied petroleum gas. However, the more spaced-apart burners used to provide selective weed control between rows of crops have a lower heat output and require a lower pressure of liquefied petroleum gas.

It is an object of the present invention to overcome or minimise this problem.

According to the present invention there is provided apparatus for controlling vegetation by burning comprising : a mounting frame for attachment to a vehicle ; a tank, for storage of a liquefied petroleum gas mounted on the mounting frame ; a boom assembly demountable on the mounting frame ; a plurality of burner assemblies secured in lateral disposition on the boom assembly ; means for controllably supplying liquid, from the liquefied petroleum gas in the tank, through a main line at a high pressure ;

means for controllably supplying gas, from the liquefied petroleum gas in the tank, through a pilot line at a lower pressure ; and means for selectively connecting the main line and/or the pilot line to the burner assemblies on the boom assembly for operation thereof.

The high pressure of the liquid in the main line, from the liquefied petroleum gas in the tank, may correspond substantially to that generated in the tank and may be between about 80 pounds per square inch and about 110 pounds per square inch.

The lower pressure of the gas in the pilot line, from the liquefied petroleum gas in the tank, may be between about 20 pounds per square inch and about 80 pounds per square inch and may suitably be about 30 pounds per square inch.

The pilot line may be derived from the main line, such as by way of one or more pressure regulating means, such one or more pressure regulating means serving to reduce the pressure from the high pressure of the main line to the lower pressure of the pilot line, whereby liquefied petroleum gas in gaseous form is provided in the pilot

line in contrast to liquefied petroleum gas in liquid form in the main line.

The main line may be connected to a main line distribution manifold, to which may be connected one or more pilot line distribution manifolds by way of the one or more pressure regulating means.

A flexible hose may be provided to connect the main line to the main line distribution manifold.

The main line distribution manifold and/or the one or more pilot line distribution manifolds may be connected by hose means to the boom assembly for connection to the burner assemblies thereon. Such hose means may be flexible hose means which may be provided with quick-fit connector means, whereby a change of boom assembly is facilitated.

Strainer means for the liquefied petroleum gas may be provided in the main line.

The demountable boom assembly may have opposite end portions which are hingeable relative to a central portion, such as by hydraulic operating means, to aid transportation of the apparatus.

Means to ignite the burner assemblies may be provided and which may comprise ignition torches located at either side of the mounting frame. Such means to ignite the burner assemblies may operate by burning liquefied petroleum gas in vapour form supplied from the storage tank and suitably by way of a pressure regulating means.

The storage tank may have one or more outlet means for the liquefied petroleum gas provided with valve means to prevent excess flow and/or pressure.

The storage tank may have an outlet means connected to the main line by way of a manually-operated, or heatsensitive, valve, which may be able to be shut manually or automatically, such as in event of development of excessive heat in the vicinity of the valve.

The storage tank may be provided with a liquid intake valve and/or a level gauge and/or a liquid bleed-off valve to prevent over-filling of the tank.

The liquefied petroleum gas may comprise propane.

The vehicle to which the mounting frame is attached may be a tractor or a trailer.

A first embodiment of the demountable boom assembly may be provided in which the plurality of burner assemblies are disposed close to one another on the boom assembly to provide a blanket of heat to underlying vegetation.

In this first embodiment the burner assemblies may each be provided with a main burner, connected to the main line supplying the liquefied petroleum gas in liquid form, and a pilot burner, for ignition of the main burner, connected to the lower pressure pilot line supplying the liquefied petroleum gas in gas form.

A heat deflector may be provided overlying the plurality of burner assemblies. Such heat deflector may incorporate thermal insulation material, such as mineral wool.

The liquefied petroleum gas in liquid and gaseous form may be supplied to the main burners and pilot burners of the burner assemblies by way of manifolds secured to the boom assembly.

One or more heat shields may be provided between the burner assemblies and the manifolds.

When the boom assembly has opposite end portions which are hingeable relative to a central portion, means may be provided to prevent operation of the main burners of the burner assemblies when the opposite end portions of the boom assembly are hinged from an operating position into a folded transportation position. Such means may comprise an interlock switch on the boom assembly which operates, when the opposite end portions of the boom assembly are folded, to shut one or more solenoid valves controlling supply of the liquefied petroleum gas in liquid form to the main burners of the burner assemblies.

Control means may be provided whereby one or more solenoid valves controlling supply of the liquefied petroleum gas in liquid form to the main burners of the burner assemblies is or are only enabled to open when the pilot burners are operating.

A second embodiment of the demountable boom assembly may be provided in which the plurality of burner assemblies are arranged in lateral spaced relationship with one another, which lateral spaced relationship may be variable, with each burner assembly being mounted on a leg, the legs each having one end adapted to contact ground and an opposite end pivotably secured to the boom assembly. With this arrangement, selective burning of

undesired vegetation, such as weeds, between rows of crops may be effected.

In this second embodiment of the boom assembly, the burner assemblies may be arranged to be supplied only with liquefied petroleum gas in gaseous form by the pilot line.

The liquefied petroleum gas in gaseous form from the pilot line may be supplied to the burner assemblies by way of one or more manifolds secured to the boom assembly.

By means of the present invention, apparatus is provided for controlling vegetation by burning which is versatile in that it allows quick interchanges between different types of demountable boom assemblies to be effected, whilst providing the necessary supply of liquefied petroleum gas thereto in high pressure liquid form and/or low pressure gaseous form. The provision of a hingeable boom assembly enables wider than hitherto assemblies to be adopted for operation while allowing for ease of transportation.

For a better understanding of the invention and to show more clearly how it may be carried into effect, reference

will now be made, by way of example, to the accompanying drawings in which : Figure 1 is a perspective view of an embodiment of apparatus according to the present invention, for controlling vegetation by burning, and provided with a desiccation boom assembly; Figure 2 is a schematic representation of the apparatus of Figure 1; Figure 3 is a perspective view of an alternative embodiment of apparatus according to the present invention, for controlling vegetation by burning, and provided with an inter-row weeding boom assembly; and Figure 4 is a schematic representation of the apparatus of Figure 2.

Apparatus for controlling vegetation by burning has a mounting frame A for attachment to a vehicle such as a tractor or a trailer. Such attachment to a tractor may be by means of a well-known three-point linkage, suitably designed to meet Category 2 of BS1841: Part 1.

A tank 1 for storing liquefied petroleum gas (LPG), such as propane, is mounted on the mounting frame A, such as by eight type M16 bolts. The tank 1 is suitably manufactured to BS5500: Category 1 and may, for example, be arranged for storage of 600 kilograms of propane.

In order to extract the liquefied petroleum gas in liquid form from the tank 1, a main outlet 2 is situated at the base of the tank 1. A further outlet 3, also situated at the base of the tank 1, is arranged to supply the liquefied petroleum gas in vapour form for a burner ignition means to be described later. This is achieved by fitting a riser tube (not shown) in the tank and which extends upwards into a vapour space above the liquid in the tank.

As is well known to the skilled person, and not shown, the tank 1 is fitted with a liquid intake valve, a hydrostatic release valve, a level gauge and a liquid bleed-off valve. The liquid intake valve enables filling of the tank with pressurised liquefied petroleum gas and the liquid bleed-off valve ensures that the tank is not overfilled. The hydrostatic release valve ensures that pressure inside the tank does not reach dangerous levels.

The level gauge is suitably arranged to enable the liquid

level of the liquefied petroleum gas in the tank 1 to be viewed without having to climb onto the mounting frame A.

The tank outlets 2,3 are equipped with excess flow valves 6,20 which shut if the volume of liquefied petroleum gas passing therethrough exceeds specified levels. The excess flow valve 6 on the main outlet 2 suitably operates if the flow exceeds 91 litres per minute.

The main outlet 2 is controlled by a manually operated or heat sensitive valve 4, which can be closed, either manually, such as by pulling a rip-cord, or automatically, in the event of excessive heat occurring in the vicinity of this valve.

The main tank outlet 2 is connected by a main line 7 to a main line distribution manifold 10, by way of a strainer 5 and a manual ball valve 8. The main line connection 7 comprises a flexible hose, such as a one inch diameter Aeroquip hose, which eliminates vibration between the tank 1 and down-stream control equipment. The strainer 5 prevents any foreign matter, carried by the liquefied petroleum gas, from reaching the down-stream control equipment.

The main line 7 to the main line distribution manifold 10 operates at the high pressure of the tank 1, which can be between 80 and 110 pounds per square inch, depending upon the ambient temperature, and such that liquefied petroleum gas in liquid form is supplied to the main line distribution manifold 10.

A hydrostatic relief valve 9 is provided on the main line distribution manifold 10.

The main line distribution manifold 10 is connected to two pilot line distribution manifolds 17 by way of pressure regulators 15, incorporating pressure gauges.

Such pressure regulators 15 reduce the pressure from the high pressure at the main line distribution manifold 10 to a lower pressure of between 20 and 80 pounds per square inch, whereby liquefied petroleum gas in gaseous form is provided at the pilot line distribution manifolds 17, in contrast to liquefied petroleum gas in liquid form at the main line distribution manifold 10. The pressure at the pilot line distribution manifolds 17 may be of the order of 30 pounds per square inch.

The main line distribution manifold 10 and the pilot line distribution manifolds 17 are provided with outlets having quick-release coupling arrangements 12 to enable

flexible hoses 13, 14 to be readily connected thereto. Solenoid valves 11 are provided at the outlets where the quick-release coupling arrangements 12 are located, in order to control supply of liquefied petroleum gas from these outlets.

Referring specifically now to Figures 1 and 2, a boom assembly B is demountable on the mounting frame A. Such boom assembly B may, for example, be about 6 metres from end to end and has opposite end portions 28,30 which are hingeable relative to a central portion 32. The end portions 28,30 can therefore be folded, such as by being hinged upwardly, and suitably by hydraulic operating means (not shown), to facilitate transportation of the apparatus.

Twenty burner assemblies 19, in four groups of five, are disposed close to one another along the boom assembly B.

Such burner assemblies 19 may comprise type LT 2 %-12 LPS liquid spray torches manufactured by Flame Engineering of Kansas, USA. Each burner assembly 19 incorporates a main burner and a pilot burner for igniting the main burner. Each main burner requires a supply of high pressure liquefied petroleum gas in liquid form, from the main line distribution manifold 10. Each pilot burner requires a supply of lower pressure

liquefied petroleum gas in gaseous form, from the pilot line distribution manifolds 17. Accordingly, four manifolds 16 are provided on the boom B, which are connected to the pilot burners of the burner assemblies 19 and are also connected to the pilot line distribution manifolds 17 by means of quick-connect flexible hoses 14.

Four further manifolds 18 are provided on the boom B, which are connected to the main burners of the burner assemblies 19 and are also connected to the main line distribution manifold 10 by means of quick-connect flexible hoses 13.

The boom assembly B is arranged as a desiccation boom to provide a concentrated blanket of heat to underlying vegetation, such as for general overall weed control or for desiccation of haulm of crops, such as potatoes.

As shown in Figure 1, a metal heat deflector 34 is provided overlying the burner assemblies 19 along the boom assembly B, and suitably incorporating a layer of thermal insulation material, such as mineral wool. The heat deflector 34 serves to retain heat, to maximise the heat available from the main burners of the burner assemblies 19 for vegetation control, and also serves to minimise the effect of wind disturbance on the flame produced by the main burner of each burner assembly 19.

Heat shields 36, such as of stainless steel, are provided between the burner assemblies 19 and the manifolds 16, 18 on the boom assembly B, to prevent vaporisation of liquefied petroleum gas in liquid form in the manifolds.

One or more interlock switches (not shown) may be provided on the boom assembly B to cooperate with solenoid valves to prevent operation of the main burners of the burner assemblies 19 when the end portions 28,30 of the boom assembly B are hinged from an operating position into a folded transportation position. Such solenoid valves operate to interrupt the supply of liquefied petroleum gas to the main burners of the burner assemblies 19.

Control means (not shown) may be provided whereby one or more solenoid valves controlling supply of the liquefied petroleum gas in liquid form to the main burners of the burner assemblies 19 is or are only enabled to open when the pilot burners of the burner assemblies 19 are operating.

Referring specifically now to Figures 3 and 4, a boom assembly C is demountable on the mounting frame A. Such boom assembly C may, for example, be about 6 metres from end to end and has opposite end portions 38,40 which are

hingeable relative to a central portion 42, to facilitate transportation of the apparatus.

Burner assemblies 26 are arranged in lateral spaced relationship with one another and mounted on legs 44.

The legs 44 have one end 46 adapted to make sliding contact with the ground and an opposite end 48 pivotably secured to the boom assembly. Such opposite end 48 of each leg 44 is arranged to be laterally adjusted in position relative to the corresponding end of an adjacent leg, whereby the spacing between the legs, and hence between the burner assemblies 26, can be varied. The boom assembly C can therefore be adjusted with regard to the spacing between rows of crops to enable inter-row weeding to be carried out by burning weeds between the rows of crops.

The burner assemblies 26 suitably comprise type LT 1 X 8D burners, manufactured by Flame Engineering of Kansas, USA. Such burners are arranged to operate from the liquefied petroleum gas in gaseous form supplied from the pilot line distribution manifolds 17.

Accordingly, a row of manifolds 50 are provided on the boom assembly C. Such manifolds 50 are connected to the burner assemblies 26 and are also connected to the pilot

line distribution manifolds 17 by means of quick-connect flexible hoses 14.

With either of the boom assemblies B and C, it is necessary to provide ignition means for the burner assemblies 19 and 26. This is achieved by providing ignition torches 25 extending from either side of the mounting frame A. The ignition torches 25 are supplied with liquefied petroleum gas in vapour form obtained from the tank outlet 3 and supplied to a manifold 23 by way of excess flow valve 20, a pressure regulator 21 with a pressure gauge, and a flexible hose 22. The ignition torches 25 are connected to the manifold 23 by way of flexible hoses and manual ball valves 24.

Control boxes (not shown) may be provided for operating the apparatus. A main control box may be mounted inside a cab of a tractor on which the apparatus is mounted.

Two pilot control boxes may be located on either side of the mounting frame A.

The main control box contains four sectional switches that activate the main line control valves, when the desiccation boom is in use. The circuit is designed so that the main line control valves will only operate when the pilot burners are operating. An additional safety

feature is an interlock switch, mounted on the desiccation boom, which ensures the main line control valves cannot operate if the outer booms are raised.

The pilot control boxes contain momentary push button switches that operate the pilot valves. They are located so that each of the sections can be ignited promptly, avoiding the build up of a gas cloud. The circuit is designed so that if any emergency-stops, located at each of the control boxes, are operated, the pilot valves must be reset before operation can commence. To achieve this, a safety iclay is installed within the circuit, which is located within the main control box. Before the pilot valves can be reset, the main reset switch located on the main control box must be activated.

Claims

1. An apparatus for controlling vegetation by burning comprising: a mounting frame for attachment to a vehicle; a tank, for storage of a liquefied petroleum gas mounted on the mounting frame; a boom assembly demountable on the mounting frame; a plurality of burner assemblies secured in lateral disposition on the boom assembly; means for controllably supplying liquid, from the liquefied petroleum gas in the tank, through a main line at a high pressure; means for controllably supplying gas, from the liquefied petroleum gas in the tank, through a pilot line at a lower pressure; and means for selectively connecting the main line and/or the pilot line to the burner assemblies on the boom assembly for operation thereof.

2. An apparatus as claimed in claim 1, wherein the high pressure of the liquid in the main line, from the liquefied petroleum gas in the tank, corresponds substantially to that generated in the tank.

3. An apparatus as claimed in claim 1 or 2, wherein the high pressure of the liquid in the main line, from the liquefied petroleum gas in the tank, is between about 80 pounds per square inch and about 110 pounds per square inch.

4. An apparatus as claimed in any preceding claim, wherein the lower pressure of the gas in the pilot line, from the liquefied petroleum gas in the tank, is between about 20 pounds per square inch and about 80 pounds per square inch.

5. An apparatus as claimed in claim 4, wherein the lower pressure of the gas in the pilot line, from the liquefied petroleum gas in the tank, is about 30 pounds per square inch.

6. An apparatus as claimed in any preceding claim, wherein the pilot line is derived from the main line, such as by way of one or more pressure regulating means, such one or more pressure regulating means

serving to reduce the pressure from the high pressure of the main line to the lower pressure of the pilot line, whereby liquefied petroleum gas in gaseous form is provided in the pilot line in contrast to liquefied petroleum gas in liquid form in the main line.

7. An apparatus as claimed in any preceding claim, wherein the main line is connected to a main line distribution manifold.

8. An apparatus as claimed in claim 7, wherein a flexible hose is provided to connect the main line to the main line distribution manifold.

9. An apparatus as claimed in claim 7 or 8, wherein the main line distribution manifold is connected by hose means to the boom assembly for connection to the burner assemblies thereon.

10. An apparatus as claimed in claim 9, wherein the hose means is flexible hose means which is provided with quick-fit connector means, whereby a change of boom assembly is facilitated.

11. An apparatus as claimed in any of claims 7 to 10, wherein the main line distribution manifold is

connected to one or more pilot line distribution manifolds by way of one or more pressure regulating means.

12. An apparatus as claimed in claim 11, wherein the one or more pilot line distribution manifolds are connected by hose means to the boom assembly for connection to the burner assemblies thereon.

13. An apparatus as claimed in claim 12, wherein the hose means is flexible hose means which is provided with

quick-fit connector means, whereby ct chcinge uf boom assembly is facilitated.

14. An apparatus as claimed in any preceding claim, wherein strainer means for the liquefied petroleum gas is provided in the main line.

15. An apparatus as claimed in any preceding claim, wherein the demountable boom assembly has opposite end portions which are hingeable relative to a central portion to aid transportation of the apparatus.

16. An apparatus as claimed in claim 15, wherein the opposite end portions are hingeable by hydraulic operating means.

17. An apparatus as claimed in any preceding claim, wherein means to ignite the burner assemblies is provided.

18. An apparatus as claimed in claim 17, wherein the ignition means comprises ignition torches located at either side of the mounting frame.

19. An apparatus as claimed in claim 17 or 18, wherein the ignition means to ignite the burner assemblies operates by burning liquefied petroleum gas in vapour form supplied from the storage tank and suitably by way of a pressure regulating means.

20. An apparatus as claimed in any preceding claim, wherein the storage tank has one or more outlet means for the liquefied petroleum gas provided with valve means to prevent excess flow.

21. An apparatus as claimed in any preceding claim, wherein the storage tank has one or more outlet means for the liquefied petroleum gas provided with valve means to prevent excess pressure.

22. An apparatus as claimed in any preceding claim, wherein the storage tank has an outlet means connected to the main line by way of a valve, which is able to be shut, such as in event of development of excessive heat in the vicinity of the valve.

23. An apparatus as claimed in claim 22, wherein the valve is manually operated.

24. An apparatus as claimed in claim 22, wherein the valve is heat-sensitive and is able to be shut

C. lUiO. L-i-Gcl. iy.

25. An apparatus as claimed in any preceding claim, wherein the storage tank is provided with a liquid intake valve.

26. An apparatus as claimed in any preceding claim, wherein the storage tank is provided with a level gauge.

27. An apparatus as claimed in any preceding claim, wherein the storage tank is provided with a liquid bleed-off valve to prevent over-filling of the tank.

28. An apparatus as claimed in any preceding claim, wherein the demountable boom assembly is provided in which the plurality of burner assemblies are disposed close to one another on the boom assembly to provide a blanket of heat to underlying vegetation.

29. An apparatus as claimed in claim 28, wherein the burner assemblies are each provided with a main burner, connected to the main line supplying the liquefied petroleum gas in liquid form, and a pilot burner, for ignition of the main burner, connected to the lower pressure pilot line supplying the liquefied petroleum gas in gas form.

30. An apparatus as claimed in claim 29, wherein the liquefied petroleum gas in liquid and gaseous form is supplied to the main burners and the pilot burners of the burner assemblies by way of manifolds secured to the boom assembly.

31. An apparatus as claimed in claim 30, wherein one or more heat shields are provided between the burner assemblies and the manifolds.

32. An apparatus as claimed in claims 29,30 or 31, wherein means is provided to prevent operation of the

main burners of the burner assemblies when the opposite end portions of the boom assembly are hinged from an operating position into a folded transportation position.

33. An apparatus as claimed in claim 32, wherein such means comprise an interlock switch on the boom assembly which operates, when the opposite end portions of the boom assembly are folded, to shut one or more solenoid valves controlling supply of the liquefied petroleum gas in liquid form to the main

burners of the burner assemblies.

34. An apparatus as claimed in claim 33, wherein control means is provided whereby one or more solenoid valves controlling supply of the liquefied petroleum gas in liquid form to the main burners of the burner assemblies is or are only enabled to open when the pilot burners are operating.

35. An apparatus as claimed in any preceding claim, wherein a heat deflector is provided overlying the plurality of burner assemblies.

36. An apparatus as claimed in claim 35, wherein the heat deflector incorporates thermal insulation material.

37. An apparatus as claimed in claim 36, wherein the thermal insulation is mineral wool.

38. An apparatus as claimed in any one of claims 1 to 27, wherein the demountable boom assembly is provided in which the plurality of burner assemblies are arranged in lateral spaced relationship with one another.

39. An apparatus as claimed in claim 38, wherein the lateral spaced relationship is variable.

40. An apparatus as claimed in claim 38 or 39, wherein each burner assembly is mounted on a leg.

41. An apparatus as claimed in claim 40, wherein the legs each have one end adapted to contact ground and an opposite end pivotably secured to the boom assembly to provide selective burning of undesired vegetation between rows of crops.

42. An apparatus as claimed in any of claims 38 to 41, wherein the burner assemblies are arranged to be supplied only with liquefied petroleum gas in gaseous form by the pilot line.

43. An apparatus as claimed in claim 42, wherein the liquefied petroleum gas in gaseous form from the pilot line is supplied to the burner assemblies by way of one or more manifolds secured to the boom assembly.

44. An apparatus as claimed in any preceding claim, wherein the liquefied petroleum gas comprises propane.

45. An apparatus as claimed in any preceding claim, wherein the vehicle to which the mounting frame is attached is a tractor.

46. An apparatus as claimed in any preceding claim, wherein the vehicle to which the mounting frame is attached is a trailer.

47. An apparatus for controlling vegetation by burning substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.