WO1984003414A1

WO1984003414A1 - A method and an apparatus for controlling of fluid flow, particularly in automatic irrigation systems in greenhouses

Info

Publication number: WO1984003414A1
Application number: PCT/DK1984/000014
Authority: WO
Inventors: Oejvind Ellegaard
Original assignee: Ellegaard Haveagentur V Ella E
Priority date: 1983-03-01
Filing date: 1984-02-28
Publication date: 1984-09-13
Also published as: EP0136308A1; DK106583D0; DE3490110T1; DK106583A

Abstract

For the regulation of fluid flow, particularly in automatic irrigation systems for smaller hobby-greenhouses, a movably suspended regulation member (30) of strongly suctorial material, viz. synthetic felt is used, which is connected to the growth medium, e.g. the soil, by means of suctorial wicks (32) as the heaviness (weight) of the regulation member in wet heavy condition respectively in dry, lighter condition via a lever (12) is used to activate a valve (18) at opposite end of the lever (12) which being spring loaded by means of a spring (36) to establish the fluid flow through the valve (18) when the regulation member (30) is dried up corresponding to the growth medium (6) lacking water.

Description

A method and an apparatus for controlling of fluid flow, particularly in automatic irrigation systems in greenhouses.

The present invention relates to a method for controlling the water supply to greenhouse plants - even from very complex methods particularly for professional use in market gardenings comprising sensitive electronic equipment for detecting the humidity of the growth medium in the form of soil, sphagnum or mineral wool plus complete with dung dosing system and irrigation system with as well electronically controlled valve functions plus other often also electronic regulation equipment, to very simple methods particularly for hobby use consisting of smaller reservoirs to which the water supply by way of example is controlled by simple cistern valves, as the watering out by way of example takes place via siphon system and dripping tubes.

Primarily, the invention concerns a controlling method for use in automatic irrigation systems for smaller hobby greenhouses, as such systems most often do. not comprise proper regulation equipment beyond simple temperature and air humidity sensors are necessary combined with thermo cylinders for opening and closing of windows for regulation of air temperature and air humidity.

It is the purpose of the invention to provide a method for controlling of fluid flow, particularly in automatic irrigation systems for smaller hobby greenhouses, and by means of which it becomes possible in a very simple manner to control the need of irrigation dependent on the humidity of the growth medium.

The method according to the invention is characterized in that for the registering of the humidity of the growth medium, e.g. the soil, or of a fluid distribution layer, e.g. a felt plate, is used a member of subtorial material, e.g. felt, which is connected with the growth medium or the fluid distribution layer, the heaviness (weight) of which in wet and dry condition, respectively, is used to activate the valve to close and to open for the irrigation water, respectively. Hereby is obtained a very simple and precise method for controlling the humidity of the growth medium and furthermore a method, which requires a minimum of installation if any at all, that is if irrigation water is available from a natural supply. The suctorial regulation member is connected with the growth medium by means of one or more wicks through which water from the growth medium may be sucked up if the humidity is sufficiently high, and through which the water may again be sucked out from the regulation member as the growth medium is again being dried up. The heaviness of the regulation member, i.e. the weight thereof in heavy water-containing condition and in light less water filled or dry condition may thus be used to open and close directly the water supply, e.g. to a system of dripping tubes, which may supply a larger number of plants also rather remote from the wicks of the regulation member, since of course these should be positioned in connection with the growth medium at a representative position, i.e. in a position which neither is particularly exposed to drying up nor to be extraordinarily watered.

In order to cover various needs for irrigation with one and the same regulation member, e.g. decided of the growth stage or the time of the year in general, it may be appropriate in a controlled manner to supply water directly from the secondary side of the valve to the regulation member, i.e. to arrange for a regulation feedback. Fur thermore, the suctorial regulation member can be springyly suspended in such a manner that the spring tension can be adjusted depending on the need of irrigation and depending onpossibly changed absorption capacity due to lime and/or salt depositing in the regulation member whereby the self-weight thereof is also changed.

In addition the invention relates to the apparatus specified in claims 3-10 for performing the method according to the invention.

In the following the invention is described in more detail with reference being made to the accompanying drawings, in which:-

Fig. 1 shows an embodiment of an apparatus according to the invention, Fig. 2 a principle sketch for illustration of the method according to the invention. Fig. 3 a mini-greenhouse with an apparatus according to the invention, and Fig. 4 another embodiment according to the invention.

The apparatus shown in Fig. 1 consists of a housing 2 having two soil spears 4 for fixing the apparatus in a low position above the soil surface 6. A rear side plate member 8 of the housing 2 is provided with a bearing brocket 10 on which a lever 12 is pivotally mounted at 14. The lever 12 is at lefthand end provided with a permanent magnet 16 cooperating with a valve 18 which via a tube 20 is supplied with water from the mains. The valve 18 which is a so-called membrane activated valve, e.g. of the type which is usually being activated electromagnetically, is at the secondary side provided with a coupling nut 22 from which branches of a larger number of dripping tubes 24 extend. The valve 18 is at the secondary side furthermore provided with a small turning tap 26 for a thin tube 28 supplying water to a regulation member 30 suspended at the opposite end of the lever 12. The regulation member 30 consists of a strongly suctorial material, e.g. felt, being rolled up in a short reel and having two wicks 32 also of felt or a corresponding strongly suctorial material. The wicks 32 are as anticipated spread out right under the soil surface 6, i.e. in good contact with the growth medium since the wicks 32 between the soil surface 6 and the regulation member 30 is sufficiently loose to ensure that the felt member 32 is free to move somewhat up and downwards as anticipated with the arrow 34.

The lever 12 is at righthand side, i.e. at the longer moment arm of the lever 12, springloaded upwards by means of a tension spring 36 the tension of which may be adjusted by means of a regulating screw 38 at the top of the housing 2. Hereby the sensitivity of the apparatus may be adjusted as an increased tension of the lever 12 decreases the sensitivity of the apparatus corresponding to the regulation member 30 being able to close the valve 18 in a lighter condition. Another possibility of adjustment consists in "cheating" the regulation member 30 by supplying more or less water directly thereto via the turning tap 26 and the tube 28 which as shown debouches above the regulation member 30. By thus supplying water directly from the secondary side of the valve 18 to the regulation member 30 is caused an earlier closing of the valve 18 than of the regulation member 30 by itself has to suck up a corresponding fluid quantity from the growth medium via the wicks 32. In other words, the re gulation member 30 is "cheated" to conceive the growth medium as sufficiently wet, i.e. that the need for water is artificially reduced via the feedback tube 38 which still only supplies water to the regulation member 30 when the valve 1 8 is open. By the way the valve 18 is closed instantly when the permanent magnet 16 is swung upwards by the lever 12 as a spring loaded disc inside the valve 18 hereby is released and closes off the fluid downstream from the rear side of the valve membrane. The water pressure is built up quickly behind the valve membrane whereby this closes off the main stream of the valve. In this way it is a very little external effort which is necessary for activating the closing/opening function of the valve 18.

Instead of the described valve 18 may be used an usual cistern valve which is shut by downward movement of the short lever portion when the long lever portion is correspondingly moved upwards, which may be caused by letting the regulation member 30 influence the lever 12 via a pulley positioned above the right end thereof as the regulation member 30 in this case is suspended in a string which via the pulley transmits a downward movement of the regulation member 30 to an upwardly directed pull in right end of the lever 12 which may have a suitable length for creating a sufficient momentum to activate the valve 18. In the right hand side of Fig. 1 is in dotted lines shown the lever 12 prolonged out through the side of the housing 2. Hereby the actual regulation condition of the apparatus may be observed from the outside, and if desired the lever 12 may be activated directly from the outside for possible shutting or opening the valve.

Fig. 2 shows the method principle according to the inven tion. From a fluid supply 40 water is sucked up via a wick 42 which by means of a valve slot 44 being separated from a fluid distribution layer 46 of a suctorial material, e.g. synthetic felt, which by a heat treatment becomes strongly suctorial. In front of the valve slot 44 is below the same springily suspended a valve member 48 in the form of a reel of felt, of which a free end constitutes a wick 50 being connected to the fluid distribution layer 46. The felt reel 48 is suspended in a tension spring 52 which by means of a regulating screw 54 may be given a suitable tension corresponding to the felt reel 48 iu jhy or less wet condition, i.e. in light condition, may be lifted upwardly in order to shut the slot valve 46 in supplying water from the wick 42 to the fluid distribution layer 46 which may consist a under watering felt mat, e.g. for potted plants.

When the felt reel 48 forms connection between the wick 42 and the fluid distribution mat 46, the felt reel 48 per se sucks up water too. Hereby the felt reel or the valve member 48 becomes more heavy and when the spring force of the spring 52 is exceeded the felt reel 48 is weighed down and opens the valve slot 44 or interrupts the fluid flow from the wick 42 to the fluid distribution mat 46 and to the felt reel 48 per se. In the course of time the felt reel 48 supplies the sucked up water to the fluid distribution mat 46 via the wick 50, the sucking capacity of which together with the spring tension determines the cycle of the system.

In fig. 3 is shown a so-called mini-greenhouse with an irrigation system according to the invention. A tray shaped lower portion 56 is beneath a support plate member 58 provided with a water reservoir 60 from which a wick 62 of synthetic felt sucks up water along an inclin ed wall portion 64. The support plate 58, which is provided with a number of transverse, open support wall portions 66, ends in a distance from the inclined wall portion 64 for constituting a valve slot 68. From this is along the underside of the support plate 58 positioned a narrow length of suctorial felt 70 which from the valve slot 68 extends to about the middle of the support plate 58 and upwards through an opening to a position under a fluid distribution mat 72 being spread out at the top of the support plate 58 in order to, as shown, underwater smaller potted plants 74 with or without a transparent cap portion 76.

Above the valve slot 68 is on one end of a lever 78 positioned a felt valve member in the form of a small felt reel 80. At the opposite end of the lever 78 is positioned a regulation member in the form of a larger felt reel 82 of which an outer turn proceeds in a loose wick 84 connected with the fluid distribution mat 72. The lever 78 is spring loaded by means of a tension spring 86 with associated regulating screw 88. Besides, the lever 78 cooperates with an external spring activated indicator 90 being able to show the actual valve condition from outside as the lower portion 56 and the housing around the irrigation weight normally consists of non-transparent plastic. Regarding the function of the automatic irrigation system of the mini-greenhouse is referred to the above mentioned specified explanation.

Fig. 4 shows another embodiment of the irrigation method according to the invention. A lever 92 has at one. end of the valve member 94 of felt, and at the opposite end thereof is suspended a regulation member 96 with wicks 98 being inserted below an irrigation mat 100 starting from a valve slot 102 opposite to a supply wick 104.

Functionally reference being made to Figs. 1 and 2 as the embodiment shown in Fig. 4 constitutes a combination proportional to Figs. 1 and 2 corresponding in principle to the automatic irrigation system by the mini-greenhouse of Fig. 3.

The invention is in general explained with reference to felt as suctorial material and more generally to so-called synthetic felt consisting of polypropylene, polyester and rayon. Synthetic felt having fixed dimensions (shrinkproof) in wet as well as in dry condition has achieved its strong suctorial quality by heat treatment. Synthetic felt even stands machine washing. Among other suctorial materials being usable in connection with the invention instead of synthetic felt may be mentioned cotton, wool, mineral wool, natural sponge or artificial sponge and even so-called super suctorial paper laminate of the type used in paper diapers.

As mentioned the main aspect of the invention is obtaining an optimal regulation of water supply by means of a minimum of technical apparatus portions and entirely without external energy supply - other than from water, e.g. from the mains.

As mentioned in connection with the apparatus according to the invention shown in Fig. 1 the irrigation interval may be determined by supplying a certain quantity of water directly to the regulation member 30 via the turning tap 26 and the tube 28. The tap 26 may in order to ensure a certain constant water supply to the regulation member 30 be thus adapted that the tap 26 cannot be entirely shut so that when the valve 18 otherwise is open, a certain quantity of water is always supplied directly to the regulation member 30. Alternatively, this direct water supply to the regulation member 30 may take place via a quite separate connection to a regulation valve which is adjusted dependent on the actual water pressure.

Claims

C L A I M S :

1. A method for controlling fluid flow, particularly in automatic irrigation systems for greenhouses, and by which water is supplied via a valve being controlably connected with means for registering the humidity of the growth medium, c h a r a c t e r i z e d in that for the registering of the humidity of the growth medium, e.g. the soil, or of a fluid distribution layer, e.g. a felt plate, is used a member of suctorial material, e.g. felt, which is connected with the growth medium or the fluid distribution layer, the heaviness (weight) of which in wet and dry condition, respectively, is used to activate the valve to close respectively to open for the irrigation water.

2. A method according to claim 1, c h a r a c t e r i z e d in that the member of suctorial material in a controllable manner is supplied with water directly from the secondary side of the valve.

3. An apparatus for performing the method according to claim 1 and comprising a valve (18) for regulation of the water supply by way of example to an automatic irrigation system of greenhouses and means (30) being controlably connected to the valve for registration of the need for water, c h a r a c t e r i z e d in that the control and registration means consist of a member (30) of suctorial material, said member (30) being movably mounted and connected to the growth medium (6) in such a manner that the heaviness (weight) of the member in wet and dry condition, respectively, can activate the valve (18) to close respectively to open for the irrigation water as the member (30) is spring loaded to in dry condition, i.e. in light condition, to establish the fluid flow through the valve (18).

4. An apparatus according to claim 3, c h a r a c t e r i z e d in that the valve consists of a magnet activated membrane valve (18) which is activated by a permanent magnet (16) mounted at one end of a pivotable lever (12) at the opposite end of which the member (30) consisting of suctorial material is suspended.

5. An apparatus according to claims 3 and 4, c h a r a c t e r i z e d in that the valve (18) at the secondary side thereof is provided with a number of dripping tubes (24) for distribution of water to individual irrigation objects and being provided with a regulation connection (28) for the supply of water via a regulating tap (26) directly to the suctorial member (30) .

6. An apparatus according to claim 3, c h a r a c t e r i z e d in that the valve consists of a slot (44, 102) between two suctorial material layers, e.g. of felt, and of a movable valve member (48, 94) also consisting of suctorial material, e.g. felt, said valve member (48, 94) being adapted to constitute connection across the valve slot (44, 102) .

7. An apparatus according to claim 6, c h a r a σ t e r i z e d in that the felt valve member (80, 94) is mounted at one end of a pivotable lever (78, 92) at the opposite end of which the member (82, 96) consisting of suctorial material is suspended.

8. An apparatus according to claim 6, c h a r a c t e r i z e d in that the movable felt valve member consists of a springily suspended felt reel (48).

9. An apparatus according to claims 6 and 7, c h a r a c t e r i z e d in that the movable suctorial valve member and the member consisting of suctorial material consist of felt reels (80, 82) positioned at opposite ends of a lever (78) .

10. An apparatus according to claim 9, c h a r a c t e r i z e d in that both the felt reels are rolled directly around opposite ends of the lever.