GB2244902A - Sub surface fluid distribution apparatus - Google Patents

Abstract

The invention provides apparatus for distributing a fluid into the soil. The apparatus comprises a porous pipe adapted for placement in soil below a surface such as a lawn or other grassed area. The pipe is connected to a fluid supply via means which operate to heat or cool the fluid. The fluid is dispersed from the pipe into the surrounding soil thereby heating or cooling the soil. The fluid used may be water or preferably air and can effectively provide under soil heating for a grassed field where required. The fluid may contain additional components such as nutrients, or fungicides to provide additional soil conditioning.

Description

SUB SURFACE FLUID DISTRIBUTION APPARATUS This invention relates to sub surface fluid distribution apparatus especially such apparatus operable to supply a quantity of heated or conditioned air into soil below ground level.

It is known to provide a porous hose or pipe below soil level in order to provide measured amounts of water to agricultural or horticultural sites, gardens, lawns, playing fields etc. Such a porous pipe may be made primarily of crumbed rubber tyres or small granular size mixed with a binder as described in US Patent No.

4168799.

Such hoses can be used to promote plant growth and crop production by supplying water direct to the root area of the crop or plant. Thus the commonly occurring problem of water penetrating from soil level to root level is overcome.

A separate problem often encountered particularly with regard to playing fields or other surfaces is that of heat dispersal. During cold weather playing surfaces may be such as to pose a danger to the surface's user, for example, by being too hard due to frost, ice etc, or by being too soft due to excess moisture on the surface.

In order to overcome such problems it has been known to provide undersoil heating systems including, for example, a closed loop pipe supplied with a heated fluid media, for example, water or air, which circulating below surface level is effective to heat the surface and therefore dry out or prevent formation of frost or ice. If water is used as a circulating media it would be advantageous to include an antifreeze additive, for example, glycol. Alternatively, an electric resistance heating system in which a matrix of electric wires is located at sub surface level is also known. In such an arrangement an electric current would be applied to the wire matrix, thereby heating up the wire in proportion to the amount of current applied.

There are, however, several problems with the systems. Firstly, the possibility of damage may cause the system to be ineffective and in any event the systems are not easily controllable except in large increments. Thus, it is difficult to calibrate the systems to permit exact amounts of heat to be inputted according to the amount of heating required.

Additionally each of these systems is designed to perform only one task which is the provision of heat.

If other problems arise a second or further system will be required, for example, to irrigate the ground if it is too hard.

It would be an advantage to provide sub surface fluid distribution apparatus which is operative to provide a variety of media for soil conditioning.

With this object in view the present invention provides sub surface fluid distribution apparatus comprising a porous pipe adapted for placement below a surface supported by support media and dispersal therethrough of fluid transport media, the pipe being connected to a fluid supply via conditioning means operative to condition the fluid such that the fluid dispersed to the support media is effective to similarly condition that media.

In a first aspect of the invention the fluid is preferably air and the conditioning means is an air heater such that air is dispersed throught the porous pipe into the surrounding soil to exit via the soil surface. In this way the soil surrounding the pipe is heated through intimate contact of the soil particles with the heated air. Additionally the use of air is effective to aerate or open the soil surface such that excess water will drain quickly away in addition to the drying effect of the hot air.

In addition to supplying heated air the air may also include additional gases which could promote growth, for example, by providing oxygen enriched air. Alternatively, soil fumigating gases could be fed into the soil to eliminate fungi, disease, weed growth or parasites. Nitrogen or carbondioxide could also be included to promote manufacture of nitrate via nitrogen fixing nodules or aiding leaf development respectively.

Preferably the air heating means is capable of reversal such that the air supply may be chilled or cooled in respect of the soil temperature. In this way air could be supplied which would be effective to slow the growth rates down where warm atmospheric conditions are promoting excess growth.

It is also possible to include within the air heating means a humidifier such that the warm air dispersed into the soil can carry moisture which would be given up to the soil as condensation and accomplish irrigation in addition to heating.

It is of course possible to use water or other fluids in place of air for the same purposes and in a second aspect of the invention the fluid media is water and the conditioning means is a water heater such that heated water is supplied to the surrounding soil.

In this aspect of the invention, in addition to heating the system, also promotes simultaneously irrigation of the soil. Soluble agents, for example, nutrients, pesticides, etc. could be added to the water where required. Alternatively, acid or alkaline additives could be used where pH balance is required within the soil.

For both aspects of the invention the porous pipe may be any convenient arrangement, for example, the pipe may be of the type described in US Patent No. 4168799 known as a leaky pipe or could be a rubber or plastic pipe into which punched or pricked holes have been made.

The use of a porous pipe is preferred as root growth cannot block pores in the pipe walls as would happen with a number of holes in a pipe wall.

Where the pipe is provided with an air heater and an air supply for application of heated air to the soil it is, of course, possible to provide an alternative link to the same pipe network which would be operative to supply water as is already known in porous pipe irrigation techniques.

The invention will be described further by way of example with reference to a preferred embodiment of the invention.

A preferred embodiment of the invention comprises a pipe or plurality of pipes made of a porous material, i.e. rubber or plastics, the pipe is made porous by way of, for example, a process according to US Patent No.

4168799. In this patent a porous flexible hose is made of crumbed rubber and synthetic rubber reclaimed from rubber tyres and a binder of polyethylene with some added sulphur. The resultant pipe has a high degree of flexibility along its length and has porous walls so that water or other fluid introduced therealong will leak out at a predetermined rate. This rate should be determined by the use which is going to be made of the pipe and the fluid supplied pressure.

The pipe is installed below the surface of, for example, the playing field such as a football pitch. at a predetermined depth which can be determined according to the upward dispersion of fluid from the pipe and the amount of coverage which is required. The pipes may be laid in parallel lines or could be disposed in a matrix or similar arrangement depending on the facilities and requirements.

The fluid supplied for the preferred embodiment is the surrounding atmosphere from which air is taken by dry fans or compressors for supplying to the pipes.

Flow valves are preferably installed or control means are provided for the dry fans or compressors such that the rate of flow and pressure of air supplied to the pipes can be adjusted as required.

Before air from the pumped means is provided to the pipe work it is heated via a heat generated source, for example, a direct or indirect gas flame. The temperature of the air exiting the heat source is monitored and controlled such that air is entering the pipe at the required temperature for dispersal to the soil. If required a humidifier could be introduced into the system so that moisture from natural sources or from a supply could be added to the air stream according to requirements. Additionally bottled gas supplies or separate gas separating plants could introduce specific gases, for example, oxygen, carbondioxide or nitrogen into the airstream for soil enrichment, again according to the requirements of the operator.

In use the fluid distribution apparatus according to the invention would provide the following advantages over known systems. The warmed air would aid growth rates thus promoting root activity of grass or turf at the surface level which activity could be controlled by the system's operator to a relatively fine degree.

Additionally the warmed air carrying moisture could be introduced into a cooler soil area thus giving the moisture up as condensation and providing irrigation.

The constant way in which such moisture would be provided would show savings in extra demand for water from mains, springs, rivers, etc.

Where warm air is applied to a waterlogged soil, the resultant aeration would open the soil up thus promoting drainage of water from the top surface and thus damage which may be caused by its use during such conditions. Additionally, the introduction of warm air into soil below surface would help avoid damage from frost or chill to crops at ground level and would prevent the formation of frost or ice at ground level which would otherwise prevent playing on such surfaces to be cancelled.

By reversing the heat generating means and extracting heat from air provided to the pipework, cold air could be supplied into the soil which could be used to slow down the rate of growth at surface level. This could be used to prevent excess growth of crops in warm weather conditions.

The addition of pure gases at sub soil level either separately or in specific combinations could meet other requirements. For example, oxygen enriched air applied to the root zone of a growing plant would aid in the root development and thus the healthy growing of that plant. Co2 enriched air circulates through the soil to the surface and combine with atmospheric air thus providing a higher Co2 level around the plant stem aiding leaf development. Soil fumigating gases could be fed into the soil to eliminate fungi, disease, weed growth and parasites etc. The addition of nitrogen to gases fed direct to the roots of legumes would aid the nitrogen fixing nodules to manufacture the necessary nitrates.Bacteria or other biologically active organisms could also be introduced into sub soil levels by way of a fluid, e.g. gas, transport media and could perform several specific predetermined functions.

Anticipated uses for such an arrangement are farms, horticultural establishments such as nurseries or glasshouses, orchards, sports grounds such as school playing fields, cricket pitches, football grounds, golf greens, fairways, horse race courses, bowling greens etc, gardens, parklands. The use of air as a heating medium may also be used to warm a synthetic surface in order to prevent frost or ice formation on such surfaces, e.g. synthetic playing surfaces, roads, driveways, access ramps for vehicles, pavements etc.

The heat generating means used to warm the air or water could be any convenient apparatus. For example, it is envisaged that direct gas flame or indirect gas flame heating means may be used although any heat exchanger, electric heater, gas, engine, duo-thermal solar or catalytic sourced heat engine may be used according to the precise amounts of heat required and the available energy sources. Cooling systems which could be used include refrigerating plants either absorption or compression designs a conveniently located cool mass of water e.g. a reservoir or subterranearn river, an evaporator or vaporising system or any chemical or mechanical means for lowering the temperature of the body which may conveniently be used.

Other applications include the heating of gravel, asphalt or other porous transport surfaces, such as aircraft runways, pavements, driveways, bridges, etc.

In such arrangements the invention will be operative to remove snow and ice. Additionally the apparatus could be used for localised heating of railway points. The apparatus may also be used to distribute conditional inert gas and anaerobic bacteria to waste land fill sites so as to promote decay and controlled production of methane or, if required, to inhibit methane formation.

Conditioned air or oxygen enriched air may include aerobic bacteria such as azotbacter, phosphobacter and streptomyces so as to promote increased yield and/or growth control.

One further use for the invention which is possible is its use to provide a permafrost barrier surrounding liquid gas storage plants. In such instances the very low temperature of such large cold masses progressively freezes surrounding soil or earth which can cause damage to local plant life, buildings etc. By surrounding such masses by apparatus according to the invention and injecting warmed atmospheric air into the soil a barrier is set up around the installation which would prevent the spreading of such permafrost at a sub soil level.

The invention is not confined to the foregoing details and variations may be made thereto within the scope of the invention. Where the pipe is required to be fairly strong or corrosion resistant a sintered metal pipe could be used. The apparatus may be arranged such that pipes in predefined zones beneath the surface to be conditioned may be controlled separately with respect to temperature of fluid media etc. Additional valves and controls will be necessary to effect such selective control Moisture and temperature control means for the apparatus may include closed loop control systems having control valves, computer systems and sensors. The sensors used may be overhead scanning devices such as radiation sensors, portable or fixed pads or probes or sub surface sensors such as thermocouples, moisture detectors, oxygen sensors etc.

Claims (8)

1. Sub surface fluid distribution apparatus comprising a porous pipe adapted for placement below a surface which is supported by the support media and dispersal therethrough of fluid transport media, the pipe being connected to a fluid transport media supply via conditioning means operative to condition the fluid temperature media such that the fluid media dispersed to the support media is effective to similarly condition that media.

2. Apparatus as claimed in claim 1 in which the fluid transport media is air and the conditioning means is an air heater such that air is dispersed through the porous pipe into the surrounding support media to exit via the surface.

3. Apparatus as claimed in claim 2 in which in additon to heating the air the conditioning means also provides oxygen enrichment.

4. Apparatus as claimed in claim 2 in which fumigating gases are added to the air.

5. Apparatus as claimed in any of claims 2 to 4 in which the air heating means is capable of reversal such that the air supply may be chilled or cooled with respect to its inlet temperature.

6. Apparatus as claimed in any of claims 2 to 4 which includes within the air heating means a humidifier such that the air dispersed into the surrounding support media can carry moisture which will condense in the media to provide irrigation thereof in addition to heating.

7. Apparatus as claimed in claim 1 in which the fluid tranport media is water and the conditioning means is a water heater such that heated water is supplied to the surrounding support media.

8. Sub surface fluid distribution apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.