A FIELD CONSTRUCTION FOR A SPORTS OR OTHER FIELD

Abstract: The object of the invention is a field construction for sports or other fields, which includes a substrate or other surface layer and beneath this a filter layer and which field is equipped with a pipe network (2, 3) located in the filter layer, which consists of numerous perforated multi-purpose pipes (3) to dry the field and to lead air through the field. In the filter layer (4) in accordance with the invention the proportion of fine material, or a granular size of less than 0,06 mm is less than 5 %, most advantageously less than 1 %, so that it is highly permeable to air, and the substrate includes so much fine material that it is essentially less permeable to air.

Description: A Field Construction for a Sports or other Field The object of the invention is a field construction for sports or other field, which includes a substrate or othe surface layer and beneath this a filter layer and which i equipped with piping in the filter layer, which piping a grea number of perforated multi-purpose pipes to dry the field an to lead air through it. In field-drains in the grass-covered areas of sports facilitie the distance between the drains varies from 8-10 meters. Uneve drying can be observed at present on many fields. At 2-4 meter from the line of the drain the field is considerably drier tha in the areas between the drains. Fields equipped with various kinds of piping are presented i the German Application and Patent Publications DE-P-924931, DE-2059383, DE-H-27 38 133, and DE-H-2840389. By means of network of pipes beneath the surface of the field it is bot warmed, and dried by draining excess water into field-drai soak-aways. The warming of the field takes place in these b blowing warmed air into the pipe network, from which it travels upwards to the surface of the field. The problem with th above-mentioned field constructions is firstly the unevenness of the blowing if the network of pipes is not very dense. Secondly, the back- and forwards flow causes fine mineral substances the enter the known field pipes. The use of electrical resistances or heating pipes in the surface of a sports field is also known, these both warming and drying the surface of the field. The distance between the resistances or pipes has been only about 20 cm, which has led to an enormous total length of resistance cables and heating pipes. The intention of this invention is to achieve a new field structure, which makes possible efficient use of the pipe network for both drying and heating and by means of which this is possible using a greater space between pipes than previously. The characteristic features of the invention appear in the accompanying Patent Claim 1. In accordance with the invention the pipe network is placed in a filter layer in which the proportion of fine mineral substances is small, so that the flow of heating air within this layer in a horizontal direction is also possible. The pipe network does not then have to be unreasonably dense. The field construction in accordance with the invention is most advantageously applied to a field equipped with a substrate in accordance with Patent Claim 3. The substrate is adapted in each individual case to have poor air permeability. Depending on the type of soil the proportion of fine mineral substances may vary greatly. In what follows the invention is illustrated by means of examples by reference to the accompanying figures, which shows one form of application of the invention in connection with a turf field of about 8000 m 2 intended for ordinary sports use. Figure 1 shows the location of the pipe network in the field Figure 2 shows the field construction in ground cross-section Figure 3 shows a multi-purpose pipe Figure 4 shows another advantageous pipe network construction The entire pipe network is located beneath the surface of the ground. The main pipes 1, which are connected to the extension pipes 2 extending to the centre of the field, are located at the side of the field. The multi-purpose pipes proper 3, which act as field drains, air-distribution and watering pipes in the other direction, are further connected to them. The substrate of the field turf is fairly conventional. It is formed, however, of a layer 5, which is clearly separate from the filter layer 4. In addition, the layer of the substrate 5 is selected of such a great proportion of fine material that it gives rise to a powerful capillary effect, by means of which the roots of the plants get water from the filter layer 4. Bot layers, 4 and 5, are about 20 cm thick. If a further separate damping layer is used beneath the turf, the hardness of the surface can be adjusted as required in each individual case. The pipe network 2, 3 is located in the filter layer 4, in which the proportion of fine material is very small. The blown air and the warmth and moisture in it are thus permitted to also travel in a horizontal direction, in which case the multi-purpose pipes 3 can be located at a reasonable distance of about 1,5- 2,5 m from one another. On account of this, there does not need to be more than 3000-4000 m of multi-purpose piping in a normally sized sports field, when the requirement of the previously mentioned electrical heating resistance or liquid circulation pipes would have been about 30 000 m. The multi-purpose pipes 3 are advantageously manufactured from conventional perforated field-drain pipes, on top of which a plastic filter screen 7 is placed. This prevents the fine material from entering the pipe and thus blocking it, Figure 3. In a field construction of this kind watering can be carried out as either spray watering or damming watering. Spraying is carried out together with blowing, whereas in damming watering the pipe network is filled directly with water. The field construction in accordance with the invention is intended for use during the entire growing season. In summer it can be used for both watering the field and for draining excess water into field-drain soak-aways. For example, by means of the known electrical heating, the field heating is used only in the spring and autumn. By means of practical experiments the pipe network has been further developed and the structure in accordance with Figure 4 has been arrived at. In a field of normal size the pipe network two sectors on each side are operated by the apparatus 8 arranged on both sides of the field. In these the flow is directed to the main pipe 1 at both sides of the field through the main control valve 9. By means of these, the full power can be directed to one sector, if required. Naturally it is possible to realize the blowing by means of only one blowing apparatus. The main pipe 1 of a diameter of 400 mm branches into distribution pipes 2 of 160 mm beneath the field and from these numerous multi-purpose 50 mm pipes branch out. By using a network structure of this kind with a filter layer 4 that is highly permeable by air, several advantages are achieved. The network structure increases operational dependability and makes it possible to reduce the diameter of the multi-purpose pipes to one half of that in a branch structure. It is quite essential that the surface layer causes the greatest air resistance. Due to this the heating, drying or watering is made even over the entire area of the sector It can be recommended, that the air permeability of the filter layer should be 3-4 times as great as that of the surface layer.

Claims: Patent Claims 1. A field construction for sports or other fields, which includes a substrate or other surface layer and beneath this a filter layer and which field is equipped with a pipe network (2, 3) located in the filter layer, which includes numerous perforated multi-purpose pipes (3) to dry the field and conduct air through the field, characterized in that the proportion of the fine mineral substances of a granular size of less than 0,06 mm, in the filter layer (4) is less than 5 %, preferably less than 1 %, so that it permits a good flow of air, and that the surface layer includes so much fine material that it is essentially less permeable by air. 2. A field construction in accordance with Patent Claim 1, characterized in that the multi-purpose pipes (3) are composed of as such known field drain pipes (6) , which are covered with fabric mesh (7) . 3. A field structure for a substrate in accordance with Patent Claims 1 or 2, characterized in that the substrate is formed of a separate layer (5) on top of a filter layer (4) , and that the proportion of fine material, granular size less than 0,06 mm, of the mass of the substrate is more than 15 %. 4. A field construction in accordance with Patent Claims 1, 2, or 3 characterized in that the thickness of the filter layer (4) is 15 - 25 cm and the thickness of the substrate is 15- 25 cm. 5. A field structure in accordance with one of Patent Claims 1-4, characterized in that the pipe network located in the filter layer (4) is formed of a network of distribution and multi-purpose pipes (2, 3), in which each multi-purpose pipe (3) crosses several transverse distribution pipes (2) . 6. A field construction in accordance with one of Patent Claims 1 -5, characterized in that the soil types of the substrate and the filter layer are selected in such a way that the specific permeability of the filter layer is at least 2,5 times as great as that of the substrate.

Inventors: HUSU AARNE, HUSU, AARNE
Applicants: HUSU KY A, A. HUSU KY
Application year: 1989
Main classification: E01C13
IPC codes: E01C13