GB2240248A - Method and apparatus for injecting air into the soil - Google Patents

Abstract

Apparatus for soil treatment of the kind in which air under pressure is injected into the soil through a probe (10) inserted into the ground, wherein a Venturi-type device (14) is provided upstream of the probe to increase the pressure and speed of air injection. <IMAGE>

Description

Method and Apparatus for the Treatment of Soil This invention relates to a method of and apparatus for the treatment of soils, especially amenity turf such as sports turf and more generally ground, often heavily compacted, in which the soil is covered by a layer of turf, by means of one of more probes inserted into the ground and through which air under high pressure is injected into the soil, for example for drainage and aeration purposes, and through which any one or more of a wide range of products, for example in the for of fungicides, herbicides, insecticides, soil conditioners and the like, can also be injected into the soil. This method or apparatus is hereinafter referred te as a method or apparatus of the kind described.

Known apparatus of the kind described has limited application to farmland and other relatively loose soils, especially for the injection of air for simple aeration' and for the insertion into the soil of fertilisers and manures entrained in the injected air. The limitations of use of the knowr. apparatus arise partly because the pressure and speed of air injection is insufficient to enable treatment of heavv or compacted ground and partly because it is not readily possible to control, vary and adjust the injecticn process, either of air or of fertiliser.

According to one aspect of the present invention, there is provided apparatus of the kind described, wherein, upstream of the probe, a Venturi-type device is provided to increase the pressure and speed of air injection.

Conveniently, the suction created at the Venturi-type device can be used to cause the entrainment into injected air of solid and liquid products such as fungicides, insecticides, silicon sands and soil conditioners. The entrainment cf products into an injected air stream is preferably made optional by provision of a valve such as a ball valve in products feed passage leading te the Venturi-type device.

Preferably, at the Venturi-type device, a metering jet for the product projects through the Venturi passage to open adjacent the Venturi exit.

The Venturi-type device, and likewise the product metering jet, are preferably embodied in an outlet block assembly having an outlet aperture to which the probe is attachable, said outlet aperture constituting the exit of an outlet passage having the Venturi passage formed at its inlet region within the block, the block assembly also having an air inlet passage leading to the entrance of the Venturi passage from an inlet aperture at the side of the block, and a product metering jet fitted within the block in communication with a product inlet passage. The block assembly preferably has two air inlet passages at opposite sides thereof, and a products inlet passage opposite the outlet passage.

Optionally, either one of two sources of compressed air, preferably of differing high pressures, car. be connected to the or either one air inlet passage under the control of valves, agaIn preferably ball valves.

In all, therefore, in a preferred embodiment, the injection process is controllable by means of up to five or more ball valves, and the opening and closing of these valves is controlled by a computerised sequenceing unit offering a variety of programmes, whereby the opening and closing of the various valves is ordered and timed to enable the injection process to be fully controlled, varied and adjusted to suit the requirements of the site and the soil treatment te be carried out.

The apparatus of the invention is especially suitable for carrying out soil treatment in compacted soils such as sports and other amenity turfs, due to the highly controlled, high pressure injection process which is made possible.

According to another aspect of the invention, therefore, there is provided a method of the kind described, especially for the treatment of highly compacted ground such as sports turfs, wherein both air injection and product injection are valve controlled by means of independently operable valves such as ball valves.

The method is preferably employed for the injection of fungicides, for example to eliminate so-calle "faIry rings", insecticides, for example to control casting worms and leatherjackets, herbicides, silica sands, soil conditioners, and water-retaining polymers and granules. The injection of abrasive materials such as sand is primarily made possible by the use of the controlling ball valves, as aforesaid, and by use of the metering jet which cooperates with the Venturi- type device, also as previously referred tc.

Further features and advantages cf the invention wil- be apparent from the following description of an embodiment, making reference to the accompanying drawings, in which: Figure 1 shows the overall system diagrammatically; Figure 2 shows an outlet block assembly; and Figure ? shows an electrical control arrangement in b:ock diagram form.

Referring to Figure 1, reference 10 denotes a probe which is inserted into the ground to enable the injection of air and/or products such as insecticides or soil conditioners into the soil, for example at a depth of up to a metre or more below the surface. The system is intended to be tractor mounted, and the probe may be inserted into the ground by means of an hydraulic ram powered from the tractor hydraulics.

The probe has four outlet apertures just above its tip, spaced around the probe, and one such aperture 12 is visible in Figure 1.

The probe is detachably mounted te an outlet block assembly, generally referenced 14, through which air and/or products from pressurised supplies thereof pass into the probe. The outlet block assembly 14 is shown in and later described with reference te Figure 2.

The outlet block assembly is able to receive air under pressure from any of four pressurised air containers, two of which containing air at a pressure of 225 p.s.i. are referenced 16, 16A and two of which containing air at a pressure up to a maximum of 30C p.s.i. are referenced 18, 18.

In addiction, the block assembly can receive c product te be injected from a pressurised product container 2. The supply of air and/or product to the block assembly 14 is controlled by five independently operable ball valves respectively referenced 22, 24, 26, 28 and 30. One way check valves 32, 34, 36 and 36 prevent reverse flow from the block assembly towards the ball valves.

Pressurisation of the containers is enabled by five pressure regulator units 40, 42, 44, 46 and 48 in an outlet supply line 50 from a compressor. Again, check valves iz, 54, 56 and 58 prevent reverse air flow.

The ball valves 22 to 30 can be air operated, or electrically operated as in the present embodiment. The microprocessor control arrangement for these ball valves is shown and later described with reference to Figure 3.

The outlet block assembly shown in Figure 2 comprises a steel block of several assembled parts which define a central chamber 60 having a bottom outlet passage 62, side air inlet passage 64, 66 and a top products inlet passage 68. The passage 68 leads to a product metering jet 70, which protrudes centrally into the upper end region of the outlet passage 62, where a Venturi-type device 72 is define.

The exit of the jet 70 opens adjacent the outlet of the Venturi restriction.

When one of the ball ales 22 te 28 for air supprny Is opened, then if the ball valve 30 for product supply is opened while the air supply valve is opened, product such as insecticide or soil conditioner is metered into the air flow beina accelerated through the Venturi 72, and is entrained in the air flow for deliver under high pressure into the soil. However, the ball valve 30 may cr may not be opened, according te requirements, and the s'ipply of air at a chose pressure, with or without supply of the product, is independently selectable.

Operation of the ball valves 22 te 30 is controlled b the microprocessor control arrangement shown in Figure 3, where reference 74 denotes a bank of solenoids which control opening and closing of the ball valves. The solenoid bank has a common exhaust 76 for the valves.

The solenoid bank 74 is fed with control signals from a CPU 78 powered from a power supply unit 80 capable of optionally serving as a d.c. battery power source or a stepped down and rectified mains source. The CPU controls the ball valve solenoids in accordance with any one of a set of programs input through a programmer unit 82 and selected by a selector unit 84. The CPU also receives an input from a distance measurement unit 86. Access unit 88 enables a selected programme to be modified in respect of operating periods, non-operating intervals, and the like.

For use, the apparatus is mounted on a tractor, the power take-offs of which are used to drive the compressor and te drive an hydraulic ram used to push the probe inte the ground.

Amongst other applications, the apparatus is especially suitable for treating amenity turf such as sports turf, which is often highly compacted. For treating an area of such turf, the probe is inserted and the apparatus operated at each point of a pattern of points appropriately spaced apart in both coordinate directions, whereby te ensure that the entire area is uniformly treated with minimum overlaps. The on-board distance measuring unit assists in ensuring uniformity of treatment.

At each treatment pcint, having inserted the probe, E switch is operated to cause the apparatus to run through a CPU controlled treatment cycle. Typically, the apparatus will be equipped with say twelve basic programs, providing as many as 1000 to 2000 different options. Additionally, special programs can be input to enable particularly difficult or unusual sites to be dealt with.

A typical treatment cycle will involve "crackling' air injection to loosen and break-up the soil but without creating an explosive effect), injection of product (such as insecticide, fungicide or conditioner or a mixture thereof, and possibly including a liquid product) and "purging" (flooding the air and/or product through the broken-up soil). The cycle may include one or more of each kind of treatment step, and include the performance of steps at different depths of probe insertion.

A selected treatment cycle is automatically carried out by operation of the valves 22 to 30 in an appropriate sequence under the supervision of control signals supplied by the CpU in accordance with the selected programme. Time periods (Tp) forming part of the programme can be adjusted.

By way of example, a typical programme may comprise:1. Open valve 22 (initial air cracking) for one TF.

2. Close valve 22 and open valve 26 (air purge) for one T 3. Open valve 3C (purge product through soil) for one p.

4. Close valve 3C.

5. One Tp delay.

6. Close valve 26.

7. Hold.

8. Open valve 24 (air cracking) for one Tp.

9. Close valve 24 and open valve 28 (purainc! for one Tp.

10. Open valve 30 (product injection) for one Tp 11. Close valve 30.

12. One Tp delay.

13. Close valve 28.

14. Reset.

Tp will typically be of the order of two seconds.

At each treatment step, it will be appreciated that the air or air with entrained product is, b virtue of the Venturi in the outlet block assembly, injected into the soil under high speed and pressure, thus ensuring efficient soil treatment even in the case of highly compacted ground such as sports turf. The exact nature of the treatment required at different sites varies, and the range of treatment programs available, enabled by means of the independently operable ball valves, ensures that in an given case the treatment carried out is that most suited to the particular site.

Various modifications of the above described method of and apparatus for soil treatment are possible within the scope of the invention hereinbefore defined.

Claims (14)

Claims

1. Apparatus of the kind described, wherein, upstream of the probe, a Venturi-type device is provided to increase the pressure and speed of air injection.

2. Apparatus as claimed in claim 1, having, in addition to an air inlet at the Venturi-type device, a product inlet at said device enabling the entrainment of a solid or liquid product into the air stream by virtue of the suction created at the Venturi-type device.

3. Apparatus as claimed in claim 2, including a valve such as a ball valve in a products supply passage leading to the product inlet.

4. Apparatus as claimed in claim 2 or claim 3, wherein a metering jet for the product projects through the Venturi passage to open adjacent the Venturi exit.

5. Apparatus as claimed in claim 4, wherein the Venturitype device and metering jet are embodied in an outlet block assembly having an outlet aperture to which the probe is attachable, said outlet aperture constituting the exit of an outlet passage having the Venturi passage formed at its inlet region within the block, the block assembly also having an air inlet passage leading to the entrance of the Venturi passage from an inlet aperture at the side of the block, and a product metering jet fitted within the block in communication with a product inlet passage.

6. Apparatus according to claim 5, wherein the block assembly has two air inlet passages at opposite sides thereof, and a products inlet passage opposite the outlet passage.

7. Apparatus according to claim 6, wherein either one of two sources of compressed air of differing high pressures can be connected to the respective air inlet passages under valve control.

8. Apparatus as claimed in claim 7, wherein the injection process is controllable by means of a plurality of valves, and the opening and closing of these valves is controlled by a computerised sequencing unit offering a variety of programmes, whereby the opening and closing of the various valves is ordered and timed to enable the injection process to be fully controlled, varied and adjusted to suit the requirements of the site and the soil treatment to be carried out.

9. A method of the kind described, according to which the pressure and speed of air injection is increased by means of a Venturi-type device upstream of the probe.

10. A method according to claim 9, applied to soil treatment of compacted soils such as sports turf and amenity turf.

11. A method according to claim 9 or claim 10, applied to the injection of fungicides, insecticides, herbicides and soil conditioners.

12. A method according to claim 11, wherein air and product injection are controlled by independently openable valves.

13. Apparatus for soil treatment substantially as hereinbefore described with reference to the accompanying drawings.

14. A method of soil treatment substantially as hereinbefore described.