GB2612299A - Delayed action automatic watering assembly - Google Patents

Abstract

A delayed action automatic watering assembly comprises a combination of a shallow vessel 1 and a float-operated bistable liquid level control device 8 connected via a liquid supply tube 9 to a liquid supply. The vessel can also accommodate at least one potted plant. Starting from a maximum liquid depth in the vessel, said vessel is adapted to raise a plant tub up higher than the height of a lowermost breather vent aperture (858, figure 8) of the liquid level control device, so that an extensive transient air tunnel (22, figure 13) is formed underneath the plant tub as the liquid depth is reduced, the liquid being consumed by the plant. As the liquid depth in the vessel reduces towards a lowermost depth, shallow wicking pads 7 disposed about the transient air tunnel ensure that the liquid in the vessel continues to be conducted upwards into the growing medium inside the plant tub. The wicking pads 7 may be located on raised platforms 6 positioned either side of a sump 4.

Description

DELAYED ACTION AUTOMATIC WATERING ASSEMBLY

Field of Invention

This invention describes an automatic watering assembly to control the periodic flow of liquid to the basal root region of a plant or plants in a tub, pot, bag or the like which is positioned within it. Essentially the assembly comprises a prior art shallow vessel, a bistable liquid level control device connected to a liquid supply, spacer pads and wicking pads. The novel arrangement ensures that each rewatering is preceded by a delay which is shown to result in healthier and more prolific plant growth. The delay may extend to many hours and ensures that the growing medium has an opportunity to become drained of liquid and aerated each time, so that the plant roots are not permanently waterlogged.

The invention particularly concerns an automatic watering assembly which employs versions of the prior art bistable liquid level control devices marketed as 'Smart-valve' in Australia and 'AQUAvalve' in the United Kingdom. Such control devices are used principally by horticulturalists, gardeners and growers of plant species. These mechanical prior art devices do not provide for a sought-after prolonged delay between each rewatering, rather they initiate an immediate rewatering each time a minimum liquid level is reached in the shallow vessel in which they are installed -the minimum liquid level being approximate the bottom of the plant tub so that the tub does not have an opportunity to become fully drained of liquid for a number of hours to allow air to permeate through the growing medium after this point is reached and before the onset of each rewatering. This is the first of two problems to be solved by the present invention.

Both of the prior art organisations supply custom shallow vessels and generally flat-bottomed plant tubs and pots of various heights which are intended for use with their own brand of liquid level control device. For economic and environmental reasons, the shallow vessels or trays and tubs and pots are generally thermoplastic injection moulded.

And specifically in the case of the trays they are made as small and as compact as possible with the result that the area where the 'valve unit' is installed is cramped, and as a consequence of this, the valve unit seldom reopens to its fullest extent for each rewatering so that the inbound liquid supply is throttled. This condition extends the filling time and leads to clogging and malfunctions. The performance of the valve unit can be improved by employing a larger tray but the historic gains from using fewer materials and having lower manufacturing costs and distribution costs is lost. One solution would be to adapt the prior art small tray so that it performs as though it were a larger tray. This is the second problem to be solved by the present invention.

As there are estimated to be in excess of one million of these systems already in use there is a pressing need to find a retrofit solution, which could extend the life of the existing tray-based systems by twenty years and more. It is an objective of the present invention to preserve the trays and the tub/pot populations and the universal method of installation and use.

Description of Prior Art

There are available at least two custom trays which are used with the bistable liquid level control devices based upon the prior art of 'Fah' -Patent 'Liquid Level Control Device' US 5,671,562 -which describes a bistable liquid level control device being a combination of a float-assisted liquid valve, a float-assisted air valve and a low-level breather vent.

This achieves a bistable effect from two pivoted float arrangements which operate valves. Where a first float is housed within an open-bottom chamber and employed to close off the supply liquid to, for example, a shallow vessel having a single continuous compartment -the device being positioned within a shallow vessel. And where a second float located outside the chamber is employed to assist in the release of a small air pressure build up within the chamber during filling and to then assist in the creation and maintenance of a partial vacuum within same, as the liquid level in the shallow vessel is reduced -in order to effect a delay between a maximum liquid level state, for example 30mm depth, and a minimum liquid level state in the region of 5mm in a shallow vessel containing one or a number of potted plants.

And where a low-level breather vent is present, which as the lowest liquid level is reached, is exposed to atmosphere and immediately initiates the process that refills the shallow vessel. Providing therefore a limited opportunity for aeration of the growing medium during the time that the liquid level reduces from its maximum in the shallow vessel to its minimum which is approximate the bottom of the plant tub.

A commercial example of this patented 'Fah' bistable liquid level control device is revealed on website www.autopot.com.au where the valve is called a Smart-valve. The commercial Smart-valve adheres faithfully to the text in claim 1 of the granted patent -which has now run its term.

A copy of this type of bistable liquid level control device is also revealed on website www.autopot.co.uk where the device is called an AQUAvalve.

There are benefits to be gained for the end user when both the shallow vessel or tray and the 'valve unit' are designed to operate optimally as a single entity and these benefits are not achievable without significant design changes to the prior art.

Consequently, when using many shallow vessels plumbed together, Growers often resort to installing an electronic timer valve between the water supply tank and groups of the prior art, to simultaneously impose a delay in the watering programme, to achieve a sought-after extended delay period between each rewatering. The timers simply turn off the water supply for as many hours as they are set for. This achieves the desired result where the shallow vessels can essentially drain out for a period -the liquid being imbibed by the plants -facilitating aeration of the growing medium, but this adds cost and complexity. What is being sought is a purely mechanical, simple and very compact solution using preferably an adaptation of the existing hardware.

Summary of the Invention

It is possible to overcome the two problems identified by considering a bistable liquid level control device and a shallow vessel operating together as a novel assembly, where the shallow vessel is adapted to raise a plant tub, pot, bag or the like up higher than is the normal casc, independent of the installed valve unit, so that an extensive transient air tunnel may be formed underneath the plant tub, pot, bag or the like as the liquid is consumed by the plant. The transient air tunnel providing a lagoon-like or reservoir catchment to accommodate a sudden rush of liquid that tries to escape from underneath the 'valve unit' installed in a cramped 'valve zone' region of the shallow vessel, when the meniscus clinging to the breather collapses and the trapped liquid and the inner float arrangement inside the 'valve unit' both descend, to open the liquid supply valve and refill the shallow vessel. And for this to be possible with the assistance of wicking pads positioned underneath a plant tub, pot, bag or the like to convey liquid from the shallow vessel up into the growing medium inside the plant tub, pot, bag or the like.

Thus, for an initial period after each refilling the shallow vessel and a lowermost portion of the plant tub, pot, bag or the like is flooded with liquid, as is the convention. Afterwhich as the plant consumes liquid the liquid level in the shallow vessel drops to below the bottom of the elevated plant tub, pot, bag or the like, the wicking pads are then the sole means for conveying liquid by capillary action and not by inundation to the growing medium and the plant.

By this method both problems referred to earlier are addressed i.e., the plant experiences a significant delay before replenishing after the liquid level has reduced to be significantly below the bottom of the plant tub, pot, bag or the like -while the transient air tunnel is being created for aeration purposes. And the transient air tunnel and any liquid filled space below it serves as a lagoon-like or reservoir catchment extension to the 'valve zone' region to enable the 'valve unit' to function in a less confined manner optimally, as though it were in a larger container.

In a first instance the present invention is intended to be a retrofit solution, i.e., adding the spacer pads, wick pads and preferably an improved replacement liquid level control device to existing prior art shallow vessels or trays and their corresponding plant tubs, pots, bags or the like so as to extend their operating life by a great many years.

The present invention may also be envisaged as a simpler assembly when employing a new custom shallow vessel or tray where the spacer pads are an integral feature of a single piece plastic injection moulding, in which case the wicking pads can be simplified also. And particularly for this to be compatible with the manufacturer's existing apertured generally flat-bottomed tubs and pots which may require a thin flat sheet (0.35mm thick) of custom-coated micro-porous root control fabric to be placed either underneath or inside the tubs and pots.

Thus, in accordance with the present invention in a first aspect there is provided a delayed action automatic watering assembly into which may be placed one or a number of plants comprising, a shallow vessel having at least one growing zone for the placement of at least one plant tub, pot, bag or the like and a valve zone, and where within said valve zone there is installed a bistable liquid level control device which can be connected to an external liquid source, and where said device opens in response to a minimum liquid level and closes in response to a maximum liquid level being achieved in the shallow vessel, and where the bottom of the plant tub, pot, bag or the like is installed at an elevated height, which height is above the height of a lowermost breather vent aperture projecting from the bistable liquid level control device, such that as liquid from an external source passes through the bistable liquid level control device into the shallow vessel the shallow vessel fills to a maximum liquid level, which level floods a lowermost region of the plant tub, pot, bag or the like principally by way of first openings in same, and where liquid is removed from the shallow vessel by the plant or plants until the liquid level reduces to be close-by the bottom of the plant tub, pot, bag or the like, where upon further liquid is conveyed from the shallow vessel to the basal region of the plant tub, pot, bag or the like by way of at least one wicking means disposed between said items principally by way of second openings in same, so as to reduce the liquid level thereby creating a transient air tunnel, communicated to atmosphere, underneath said plant tub, pot, bag or the like for aeration of the growing medium contained within, principally by way of said first openings in same, the duration of said wicking process generally defining the delay period being sought, and where as a consequence of the wicking process the liquid level in the shallow vessel reduces, progressively increasing the depth of the transient air tunnel so that when the liquid level has reduced to a predetermined minimum, to initiate the onset of refilling said tunnel is at a maximum and serves as a lagoon-like extension to the said valve zone to accommodate displaced liquid from the valve zone caused by liquid escaping from underneath the liquid level control device, so that the liquid escapes more readily as though the valve zone were larger, which action improves the operation of the liquid level control device.

The sought-after delay period may be varied by altering the wicking material, its dimensions and properties The sought-after delay period may be varied by altering the vertical displacement between the generally bottom of the plant tub, pot, bag or the like adjacent to the valve zone in the shallow vessel, and the breather vent aperture of the liquid level control device.

The sought-after delay period may be varied by altering a combination of the two features namely the height of the platforms or steps onto which a plant tub, pot, bag or the like may be placed in the shallow vessel and the wicking material, its dimensions and properties.

Preferably though not exclusively the wicking material would be sponge-like or felt-like and possess a capillary action capable of elevating a liquid to at least 20mm in height, for example a cellulose open cell sponge or a nonwoven horticultural wicking felt.

In a second embodiment very particularly, the wicking material would be in the form of at least one porous spacer pad having mechanical integrity so as to support the mass of a potted mature plant without crushing down and possess a capillary action capable of elevating a liquid to at least 20mm in height, for example constructed from loose bundled end grain Balsawood or material with similar mechanical strength and wicking properties.

In a third embodiment very particularly, the spacer pads and wicking pads would be replaced by at least one skeletonised framework, capable of supporting a mature plant in a tub, pot, bag or the like without crushing down, in conjunction with a wicking material, which material may be crushable, having a capillary action capable of elevating a liquid to at least 20mm in height. And where said skeletonised framework may be separate from and installed inside a shallow vessel or be integral with a shallow vessel, the framework being interrupted to facilitate liquid flow to the wicking material.

Preferably though not essentially a suitable bistable liquid level control device, connected to a liquid supply and positioned in a shallow vessel to deliver liquid to said vessel comprises; a housing having a first chamber with a first tunnel-like extension within which is located a liquid flow control valve having a static orifice for the passage of liquid and a movable resilient first sealing member installed in a first float arrangement, pivotally operatively engaged with said housing and moveable between an up position and a down position responsive to a level of liquid in the first chamber, and where said first float arrangement comprises a first float body having a second tunnel-like extension from one side face which extension is loosely housed within said first tunnel-like extension, the second tunnel-like extension having at least one aperture in its ceiling to facilitate the egress of liquid from above same, the first chamber being open at its bottom to allow liquid ingress and egress, such that when said float arrangement is in a down position, when the level of liquid in the shallow vessel is at or below a minimum first predetermined level, the liquid flow control valve is open to allow supply liquid from a source to enter the device, by way of a hose-fed connection, and where said device incorporates internal liquid deflector means to redirect liquid through the apertured second tunnel-like extension and through the open bottom of the device into the shallow vessel without said liquid disturbing the first float body positioned in its downmost position within the first chamber, and where at least a portion of the first tunnel-like extension would be extended upwards so that its ceiling presents a concave deflector surface of generally semi-circular form, capable of redirecting liquid that is projected upwards from the liquid flow control valve, in an arc-like fashion so as to redirect and expel said liquid more immediately downwards through the bottom of the device, and where about an upper region of the housing there is an air flow control valve having a static orifice for the passage of air and a movable resilient second sealing member installed in a second float arrangement external to and pivotally operatively engaged with said housing and moveable between an up position and a down position responsive to a level of liquid in the shallow vessel, such that when the second float arrangement rises, as a consequence of the liquid flow control valve allowing liquid to pass through the valve and into the shallow vessel the liquid level rises towards a maximum second predetermined level lifting the second float arrangement, which action opens the air flow control valve to enable trapped air to escape from the first chamber to atmosphere, allowing liquid to rise inside the first chamber, raising also the first float arrangement and closing the liquid flow control valve to prevent further liquid flow through the device and into the shallow vessel, and where the level of liquid in the shallow vessel and in the first chamber drops to a third predetermined level of liquid as a consequence of liquid being used or being removed, the second float arrangement descends to dose the air flow control valve, the first float arrangement descends also but this is not sufficient to reopen the liquid flow control valve, thereafter as the liquid level in the shallow vessel reduces still further a partial vacuum is established and maintained inside the first chamber where the trapped liquid and the first float arrangement are held aloft, and where there is an external lower mounted breather vent annexed from and communicated with the first chamber, such that when the level of liquid in the shallow vessel falls to a fourth predetermined level as a consequence of liquid in the shallow vessel being used or removed, air enters through the said breather vent into the first chamber to overcome the partial vacuum to allow the trapped liquid to flow out of the first chamber into the shallow vessel, to allow also the first float arrangement to drop down and open the liquid flow control valve to commence refilling the shallow vessel with liquid.

Preferably said internal liquid deflector means incorporated into the said first tunnel-like extension would also comprise a generally straight deflector element positioned cross- wise to the supply liquid path, emanating from the underside ceiling of the first tunnel-like extension and extending downwards in the direction of the base of the housing, which portion of said deflector element having a width less than the width of the aperture opening in the ceiling of the second tunnel-like extension within which a portion of the said deflector may reside and where said deflector may be separate from or continuous with one end of the aforementioned concave deflector surface. The generally straight deflector surface being especially important when the device is operated at lower waterhead pressures, i.e., where a liquid supply tank maybe almost empty, so that with little head pressure available the inbound supply liquid overtops the inner first float arm and travels in a generally horizontal direction towards the rear of the inner first float, before which it flows down through at least one aperture in the ceiling of the second tunnel-like extension and into the shallow vessel, and where in the case of a higher waterhead pressure, for example from a full tank of supply liquid, the supply liquid -which can be likened to a torrent -is propelled into and deflected by the concave deflector surface and then the generally straight deflector so as to be directed downwards and into the shallow vessel.

Preferably the first tunnel-like extension, close-by its intersection, has at least one offset open bottomed generally vertical hollow shaft likened to an alcove which can facilitate the outpouring of liquid in a downward direction, so that liquid that bypasses the aforementioned deflection means by way of clearances between the tunnel-like extensions and clearances between said deflector means will be redirected into the shaft or shafts to flow out of the bottom of the device, so preventing liquid from reaching and impacting against the rear face of the inner first float body.

Essentially the means for air communication between the breather vent and the first chamber is via an upper positioned aperture of a lesser cross-section than the cross-section of the breather vent, so as to throttle the passage of air entering the first chamber via the breather vent. This is to allow time for the inner float arrangement to descend in a controlled fashion to its lowermost position, and without it bouncing. If the aperture is too large the air rushes in too quickly and the inner float arrangement comes to rest in a partially descended state, i.e., not at rest on the floor of the shallow vessel -which outcome gives rise to throttled refilling of the shallow vessel.

Further it has been shown that a breather vent and communicating aperture may be positioned in a number of places around the housing and that the shape and cross-section of the breather vent aperture may be altered also -where preferably the breather vent and communicating aperture are positioned on the sidewall of the housing approximate the mid-point of the device -the device is then less prone to malfunction caused by angular displacements of the shallow vessel within which it is installed.

Again, preferably though not essentially an alternative suitable bistable liquid level control device, connected to a liquid supply and positioned in a shallow vessel to deliver liquid to said vessel comprises, a housing having a first chamber within which is located a liquid flow control valve, operatively connected with a first float arrangement moveable between an up position and a down position responsive to a level of liquid in the first chamber, the first chamber being open at its bottom to allow liquid ingress and egress, such that when said float arrangement is in a down position, when the level of liquid in the shallow vessel is at or below a minimum first predetermined level, the liquid flow control valve is open to allow the supply liquid to pass therethrough to fill the shallow vessel to a maximum second predetermined level and also to tend to fill the first chamber and to tend to raise the first float arrangement by displacing trapped air in the first chamber, and where about an upper region of the housing there is an air flow control valve, operatively connected with an externally mounted second float arrangement in communication with the shallow vessel and moveable between an up position and a down position responsive to a level of liquid in the shallow vessel, such that when the second float arrangement rises, as a consequence of the liquid flow control valve allowing liquid into the shallow vessel, the liquid level rises towards a maximum second predetermined level lifting the second float arrangement, which action opens the air flow control valve to enable trapped air to escape from the first chamber to atmosphere, allowing liquid to rise inside the first chamber, raising also the first float arrangement and closing the liquid flow control valve to prevent further liquid flow through the device and into the shallow vessel, and where the level of liquid in the shallow vessel and in the first chamber drops to a third predetermined level of liquid in consequence of liquid being used or being removed, the second float arrangement descends to dose the air flow control valve, the first float arrangement descends also but this is not sufficient to reopen the liquid flow control valve, thereafter as the liquid level in the shallow vessel reduces still further a partial vacuum is established and maintained inside the first chamber where the trapped liquid and the first float arrangement are held aloft, and where there is an external lower mounted breather vent annexed from and communicated with the first chamber, such that when the level of liquid in the shallow vessel falls to a fourth predetermined level as a consequence of liquid in the shallow vessel being used or removed, air enters through the breather vent into the first chamber to overcome the partial vacuum to allow the trapped liquid to flow out of the first chamber into the shallow vessel, to allow also the first float arrangement to drop down and open the liquid flow control valve to commence refilling the shallow vessel with liquid.

Essentially in the case of a prior art shallow vessel, spacer pads are employed to raise the elevation of the plant tubs, pot, bags or the like so that the bottoms of the said plant tubs, pots, bags or the like are higher than the lowermost breather vent aperture projecting from the bistable liquid level control device, the depth of said pads largely determining the depth of the transient air tunnel.

Essentially in the case of a prior art shallow vessel, at least one wicking pad is employed between said spacer pads, the uncompressed height of same exceeding the height of the spacer pads.

Preferably, in the case of a new custom shallow vessel said separate spacer pads are not required if the shallow vessel is manufactured to take account of the required height for installing the plant tubs, pots, bags or the like.

Preferably the liquid supply source would be a source at low pressure for example at a liquid head within a range of 0.1 to 1.5 metres (for example at a pressure of around 0.01 to 0.15 bar gauge) and more particularly at a liquid head of less than one metre. The liquid may be water-based irrigation liquid. The supply source may include a water butt for example providing the desired practical maximum liquid (water) head.

The method comprises: Standing a prior art shallow vessel on a level surface open to atmosphere; installing a bistable liquid level control device in the valve zone -in which condition both the float body arrangements are in their downmost positions so that the liquid flow control valve is open to the passage of supply liquid and the air flow control valve is closed to the passage of air, installing spacer pads and at least one wicking pad in the growing zone, and if required overlaying the growing zone with a layer (0.35mm thick) of microporous coated nonwoven root control fabric, and then standing a plant or plants in tubs, pots, bags or the like in same, supplying a liquid to the bistable liquid level control device from an external source, and operating the whole assembly such that the following occur sequentially and repeatedly; From a dry empty state liquid (e.g. water) is delivered via the bistable liquid level control device into the shallow vessel.

The liquid depth rises until a predetermined maximum liquid level is attained, for example 30mm. At this stage the second float arrangement rises fractionally opening the air flow control valve to allow air to vent from the first chamber to atmosphere. The flooded liquid depth experienced by the plant tub, pot, bag or the like is approx. 15mm.

As a consequence of this, liquid in the shallow vessel is forced upwards inside the first chamber until it is equal to the liquid level prevailing in the shallow vessel.

This buoys up the inner first float inside the first chamber which action closes the supply liquid flow control valve to the passage of any further liquid.

Liquid is consumed by the plant or plants and the liquid level in the shallow vessel reduces marginally -closing the air flow control valve and enabling a partial vacuum to be created in the first chamber to maintain the elevated liquid level in the first chamber. The liquid reduction in the shallow vessel continues until such time as the liquid level reduces to be below the bottom of the plant tub, pot, bag or the like, so that the plant tub, pot, bag or the like is effectively drained of free liquid and air can permeate through the growing medium.

Over time further liquid is removed from the shallow vessel by wicking means positioned underneath each plant tub, pot, bag or the like and this defines the delay period referred to earlier. The wicking means conducts liquid upwards and through some but not all of the apertures or open pores in the tub, pot, bag or the like. As the liquid level reduces a transient lagoon-like air tunnel forms underneath the tub, pot, bag or the like installed in the shallow vessel.

Given some knowledge of the plant's requirements the sought-after delay period that occurs before each refilling is initiated can be pre-determined to a degree to last for example for a period of less than one hour or to extend to many hours. Three hours being a very beneficial period for many plants. During the delay period as the transient air tunnel is increasing in depth, air is able to permeate the growing medium contained within the tub, pot, bag or the like by way of one or more of the unobscured apertures or pores in same, i.e., those apertures or pores which are not above any wicking means.

The wicking process continues until such time as the liquid level in the shallow vessel reduces to expose a breather vent aperture, low down on the outside periphery of the bistable liquid level control device. As the partial vacuum in the first chamber is broken air is suddenly drawn into the bistable liquid level control device to trigger the refilling of the shallow vessel, i.e., the trapped elevated liquid in the first chamber drops down and disperses into the shallow vessel, and most particularly into the transient lagoon-like air tunnel, allowing the elevated first float arrangement to descend in a determined manner, thereby opening the liquid flow control valve.

Preferred features of the method will be appreciated from the general description of the delayed action automatic watering assembly herein and the invention achieves these in admirable simple manner.

Brief Description of the Drawings

Figures 1 and 2 and 7 to 10 show an automatic watering assembly incorporating features which, operating in combination, create a sought-after delayed action before each refilling of the shallow vessel and also an improvement to the operation of the liquid level control device in accordance with the invention in perspective view, exploded view and side sectioned schematic views in various operational positions, and like numerals are used where applicable.

Figures 3, 4 and 5 show a first-choice bistable liquid level control device which is suitable for use as a part of this invention. And figures 11 and 12 show an underside perspective view of the housing and the inner float arrangement of the device shown in figures 3, 4 and 5. Figure 13 is a section (A-A] of the present invention taken from figure 7, showing how the essential transient long air tunnel for liquid to disperse into is able to form -producing two benefits namely, the time it takes for the tunnel to increase to its maximum depth before the onset of rewatering defines the sought-after delay period AND when the tunnel is at its maximum depth it provides a catchment to freely accommodate liquid dispersed by liquid escaping from underneath the liquid level control device so that the inner first float assembly can descend more definitely even though the device is installed in a confined area.

For comparison figure 6 is one example of the prior art, and figure 14 is a cross-section comparable with the section A-A from figure 7 showing how in the prior art this functionality is absent.

Figure 15 is an exploded view of the present invention illustrating how savings can be made when the shallow vessel or tray is custom manufactured, as compared with figure 2.

Figure 16 is a second embodiment where separate spacer pads and wicking pads are replaced by a stiff porous material slab, which simplifies and improves the operation of the assembly.

Figure 17 is a third embodiment where skeletonised support frameworks provide for the necessary elevated height and provide housings to accommodate wicking pads in place of the aforementioned spacer pads and wicking pads.

Figure 18 shows a common array of slitted apertures in the bottom of a square plant tub.

In the following text: Figure 1 is an example of a general perspective view of the whole assembly, Figure 2 is an exploded perspective view of the major items of figure 1, Figure 3 is a side to rear perspective view of a first-choice, bistable liquid level control device which may be employed in the whole assembly, Figure 4 is a side view of said first-choice device opened to reveal the major pivoted components, Figure 5 is a side sectioned schematic view of said first-choice device as shown in figs 3 and 4, Figure 6 is an exploded perspective view of one example of the prior art, Figure 7 is a side sectioned schematic view of the whole assembly in a dry starting condition, Figure 8 is a side sectioned schematic view of the whole assembly and where the shallow vessel is filled with liquid to a predetermined maximum level, Figure 9 is a side sectioned schematic view of the whole assembly where the liquid level is being reduced by the plant, but it is still above the breather vent, Figure 10 is a side sectioned schematic view of the whole assembly where the liquid level has reduced to a pre-determined minimum sufficient to next collapse the meniscus at the breather vent and trigger refilling the shallow vessel, Figure 11 is an underside perspective view of the housing of the first choice bistable liquid level control device as illustrated in figures 3 to 5.

Figure 12 is an underside perspective view of the inner float arrangement of the first choice bistable liquid level control device as illustrated in figures 3 to 5, Figure 13 is an end view section AA showing the transient long air tunnel due to the raised pads which facilitates the dispersal of liquid from underneath the valve unit of the present invention, Figure 14 is, similarly, an end view section showing how there is no long air tunnel possible for liquid to disperse into, in the case of the prior art, as compared with figure 13, Figure 15 is an exploded view of the items needed to assemble a custom manufactured version of the present invention, Figure 16 is an exploded view of a second embodiment similar to figure 2 whereby the stiff spacer pads and the compressible wicking pads have been replaced by a single material, being both porous and stiff, Figure 17 is an exploded view of a third embodiment similar to figure 2 whereby the stiff spacer pads and the compressible wicking pads have been replaced Figure 18 by a skeletonised support framework within which is placed a compressible wicking material, is a plan view of a square plant tub showing an arrangement of slitted apertures in the base through which irrigation water passes from the tray into the growing medium inside the tub.

Detailed Description of the Drawings

Referring to the delayed action automatic watering assembly in a first embodiment, the invention will now be described by way of example only, with reference to the figures in the accompanying drawings. Where figure 1 is a general perspective view, figure 2 is an exploded view. Figures 3, 4 and 5 show details of a first-choice bistable liquid level control device which is suitable for use in the present invention and figures 7 to 10 are side sectioned schematic views of the invention in various stages of use. Figures 11 and 12 show further details of the internal features of the first-choice bistable liquid level control device.

To keep the sectioned schematic views as simple as possible (figs. 5, and 7-10), the first-choice bistable liquid level control device has been rotated 90 degrees anti-clockwise and sectioned longwise so that the shallow vessel, the internal workings of the bistable liquid level control device and its breather vent can be presented as a single two-dimensional image. Most particularly the breather passage which is normally attached to the side of the device of the present invention, i.e., that portion which is removed to provide the section, is relocated to the front of the device to simplify the description. The external second float body is sectioned locally to reveal a resilient sealing member.

Referring to figures 1 and 2, the embodiment shown is a delayed action automatic watering assembly 0 comprising a prior art custom single compartment shallow vessel 1 which has a growing zone 2 and a bistable valve zone 3. The growing zone has a longwise shallow sump 4 running from left to right. On either side of the sump there is a shallow platform 5. The two platforms conventionally support a square plant tub having a plant therein, in a growing medium. In the present invention four rigid spacer pads 6 are added to the platforms, the pads being in the region of 10mm thick. Between each pair of spacer pads there is positioned a compressible wicking pad 7 which dry height exceeds the height of the rigid spacer pads. The wicking material overhangs the sump so that it is able to draw liquid from the sump.

For simplicity of image no plants are shown in the plant tubs in the drawings.

A suitable bistable liquid level control device 8 is installed in the valve zone 3, having a liquid supply tube 9 connected, which tube is connected to a liquid source for example a water butt (not shown). Rising from the floor 10 of the valve zone there is a TEE shaped spigot 11 anchoring means to position and secure said chosen bistable liquid level control device. There are also two forward positioned steps 12 and a rear positioned step 13 in the valve zone upon which the device 8 rests.

The wall of the shallow vessel in the valve zone has a cutaway 14 to accommodate said liquid supply hose. Most particularly the device 8 has a breather passageway 855 and breather vent 858 (fig 5) positioned to its left side approximate the middle of the shallow vessel and this is important. The device 8 also has a blind dummy breather passageway 806 (fig 2) which is used only for attaching the device to the TEE shaped spigot 11 to hold it down in the shallow vessel 1.

A first-choice bistable liquid level control device 8, for use in the automatic watering system, is based upon an improved version of the FAH patented invention Liquid Level Control Device -US 5,671,562 which describes a bistable liquid level control device as a combination of a float-assisted liquid valve, a float-assisted air valve and a low-level breather vent. The improved version described here features a novel internal liquid deflection means which enables the device to operate more efficiently and reliably in a cramped environment -this is essential if the material and manufacturing costs of the shallow vessel are to be kept to a minimum.

Figure 3 shows a front perspective view of the improved first-choice bistable liquid level control device 8 in a closed assembled form. The housing 851 and the second float arrangement 810 are visible as are the pivot lugs 828 engaged with the second float arrangement and the through hole 826 which house the stubby axles 825 on the extreme end of the second float arm 824, at the other end of which are the second float bodies 823. One of the three stubby feet 819 is shown on the side of the housing towards the front end as is the newly positioned breather passageway 855. The hollow housing is block shaped having also a first tunnel-like extension extending from one side face. Towards the rear of the extension the ceiling and the sidewalls rise upwards to create an internal concave liquid deflection surface 804. The view also shows the position of the halfmoon blind socket 806 on the front face which is used only to anchor the device to the bottom of the shallow vessel by way of the TEE shaped spigot 11 (fig 2).

Figure 4 shows a partially opened-out assembled side view of the three main components of the improved bistable liquid level control device namely, the housing 851, the inner first float arrangement 809 and the outer second float arrangement 810. The inner first float arrangement has a first float body 813 and extending from one face is a second tunnel-like extension 814. The threaded liquid supply connection 820 is shown as is one of the side hollow vertical shafts 831 which is used as a spillway to divert supply liquid away from the inner first float body. Refer also to figures 11 and 12 which are an underside perspective view of the housing 851 and the first inner float arrangement 809 in 3D.

And figure 5 shows a long-wise schematic section through the improved bistable liquid level control device where the breather vent 858 is shown communicating with the first chamber 802 via a breather passageway 855 and a horizontally communicated aperture 857.

Note that for ease of presentation the breather passageway 855, the breather vent 858 and the horizontally communicated aperture 857 have been moved from the side of the device to the front face of the device, and that the halfmoon blind socket 806 is obscured behind the breather passageway 855.

The first chamber is open at the bottom 811. Atop the housing 851 is an upper communicating aperture 805 leading to atmosphere. At the end wall 812 of the first tunnel-like extension 803 of the housing the image shows the closed uppermost air flow control valve 834 of which the resilient second sealing member 830 is a part. The figure shows the air flow control valve in a closed state where the second sealing member is pressed against the sharp-edged protruding orifice of the upper communicating aperture. For a comparison, when the second float arrangement 810 is pivoted upwards the second float arm 824 is raised (refer to figure 8) to pivot the resilient second sealing member away from contact with the communicating aperture and air can pass therethrough. The raising being due to the float bodies 823 being buoyed up by a rising liquid level in the shallow vessel or tray in which the device is placed.

Further the figure 5 shows the liquid flow control valve 822 inboard from the liquid supply connection 820 at the rear of the housing, also the resilient first sealing member 816 which is employed to close the valve when it is pressed against the sharp-edged protruding orifice 818 in the end wall 812 of the device, by the pivotal movement of the inner first float arrangement 809. Shown also are the stubby axles 815 in the first float arrangement and the mating slots 817 for pivoting and the rear stubby foot 819 under the end wall of the housing, being one of a set of three feet.

Inside the first chamber the pivoted inner first float arrangement 809 has a first float body 813 extending from which is the second tunnel-like first float arm 814 leading to a pivotal mounting and a resilient first sealing member. The figure 5 shows the raised semi-circular concave liquid deflection surface 804, which is a part of the first tunnel-like extension of the housing. And this is seen to further extend downwards as a straight deflector member 829 through the aperture 832 in the ceiling of the second tunnel-like first float arm.

The arm having a second ceiling aperture 832 where between the apertures is positioned a crosswise dividing wall 833 which serves to stiffen the component and act as a deflector and conduit for liquid to flow along. The latter of the apertures 832 operates in conjunction with the hollow generally vertical side shafts 831 to guide supply liquid downwards and out of the bottom of the device.

Refer also to figures 11 and 12 which are an underside perspective view of the housing 851 and the first inner float arrangement 809, which reveal the internal features which determine the different supply liquid pathways within the first-choice bistable liquid level control device.

Installation and operation of the delayed action automatic watering assembly: In use and referring to figures 1 to 5 for general reference and figures 7 to 10 for operational details. Place the shallow vessel 1 on a level surface where it is to be used, install a chosen bistable liquid level control device 8 connected to a liquid source (not shown) by way of the liquid supply hose 9, ensuring that the TEE shaped spigot 11 in the shallow vessel is fully engaged with the halfmoon blind socket 806. -to prevent the control device from floating.

The liquid source may be a water butt containing water and nutrients, the supply hose preferably has an isolation valve (not shown) installed to turn the liquid supply to the liquid level control device on and off Insert the four spacer pads and the two wicking pads in the growing zone in the shallow vessel as shown in figure 1. If required (optional) overlay the growing zone with a single layer (0.35mm thick) of microporous coated nonwoven root control fabric (not shown). The delayed action automatic watering assembly 0 is now complete and ready to receive a potted plant. Stand a potted plant in the growing zone of the shallow vessel.

When the isolation valve (not shown) is opened to the passage of liquid from the water butt (not shown) to the bistable liquid level control device the following takes place: Figure 7 shows a side sectioned schematic view of the whole assembly 0 in a dry starting condition whcrc the shallow vessel 1 is cmpty of liquid and a potted plant is set down in the growing zone on top of the spacer pads and the wicking pads. On the bistable liquid level control device 8 the air flow control valve 834 is closed to the passage of air and the liquid flow control valve 822 is open to the passage of the supply liquid. At this point the liquid from the source is about to pass through the bistable liquid level control device and into the shallow vessel. The section arrows A-A are used to create figure 13 which more clearly reveals the position and scale of the transient air tunnel.

Figure 8 shows a side sectioned schematic view of the whole assembly where the shallow vessel 1 is now filled to a predetermined maximum liquid level 100 -which level may be in the region of 30mm liquid depth. The inbound liquid flow control valve 822 has been closed by the buoyed up movement of the internal pivoted first float arrangement 809 inside the bistable liquid level control device 8, made possible by the buoyed up movement of the second float arrangement 810 which has moved the resilient second sealing member 830 away from obscuring the upper communicating aperture 805, allowing air to pass from the first chamber 802 to atmosphere, causing the liquid level 100 to prevail also inside the fillable regions of the bistable liquid level control device. At this stage the content of the plant tub 20 is flooded to approx. 15mm of depth, the liquid having entered principally through the unobscured slitted apertures 21 that are positioned above the sump 4.

The plant (not shown) consumes liquid from the filled shallow vessel. The liquid level reduces and both the first and second float arrangements descend -there is no drawing for this as the descent is fractional. The descent of the second float arrangement 810 closes the air flow control valve, i.e., causes the resilient second sealing member 830 to press downwards onto the upper communicating aperture, so isolating the first chamber from atmosphere. Concurrent with this there is a fractional descent of the inner first float arrangement and a small quantity of air is drawn into the first chamber, but this descent is not sufficient to open the liquid flow control valve.

By design the first-choice liquid level control device has a built-in safety margin, for example, the liquid flow control valve 822 is capable of closing off completely at 5mm below the maximum liquid level 100, i.e., there is a calculated overrun which can be accommodated by the first float body 813 becoming more submerged and by the springiness of the resilient first sealing member 816. So that a small reduction in liquid level from a maximum of 100 to the fractionally lower liquid level of 100a -in order to provide sufficient movement to close the air flow control valve 834-does not compromise the closed-off liquid flow control valve 822.

Figure 9 shows a side sectioned schematic view of the whole assembly where, as further liquid is removed from the shallow vessel the liquid level reduces until it is below the bottom of the plant tub 20 and this is referred to as liquid level 101. As can be seen from the figure, the liquid inside the bistable liquid level control device 8 remains elevated at liquid level 100a. The liquid is held aloft due to the partial vacuum that prevails inside the first chamber 802 -on account of the descended second float arrangement 810 closing the air flow control valve at the top of the first chamber.

The wicking pads 7 conduct liquid from the shallow vessel up into the tub through those slitted apertures which are above the wicking pads. Concurrent with this, due to the elevated position of the tub standing on the spacer pads 6, a lagoon-like long air tunnel 22, communicated to atmosphere, forms underneath the tub over the shallow sump 4, and this continues to increase in depth as more liquid is removed. This is revealed in figure 13 which is a sectioned end view A-A selected from figure 7, (which shows the assembly in a dry state).

The reduction in liquid level in the shallow vessel results in a drained-out state in the tub, enabling air from the long air tunnel to enter the growing medium through those unobscured slitted apertures 21 that are positioned above the shallow sump 4, (refer also to figure 18).

Figure 10 shows a side sectioned schematic view of the whole assembly, where liquid has been removed from the shallow vessel via the wicking pads to achieve a lowermost liquid level 102 -the wicking process continues. This liquid level is below the level of the breather vent 858 and the meniscus 25 -due to the surface tension -can be seen clinging on to the breather vent lip and is at the point of collapse. As with figure 9, the elevated liquid level 100a still prevails inside the bistable liquid level control device 8. The long air tunnel 22 is increasing downwards towards its maximum dimension -which is approximate the thickness of the spacer pads i.e., 10mm -above the liquid present in the shallow sump. Maximum thickness of the long air tunnel will be achieved at the moment the meniscus collapses.

Suddenly the meniscus 25 collapses and the breather vent 858 is exposed to atmosphere sufficient to draw air in through to the first chamber 802 via the breather passageway 855 (refer also to figure 5) and the horizontally communicated aperture 857 of the bistable liquid level control device 8. Consequently, the partial vacuum is broken, and the elevated liquid trapped inside the first chamber tries to descend rapidly along with the inner first float arrangement 809. Given the transient space provided by the long air tunnel 22 above the shallow sump, liquid is able to disperse from underneath the housing 851 into the valve zone by displacing standing liquid in the valve zone into the long air tunnel. This enables the inner first float arrangement to descend positively, opening the liquid flow control valve 822 to start filling the shallow vessel once more.

Geometrically the condition is the same as for figure 7 the notable difference being that at the commencement of the first refilling and for all subsequent refilling there will always be residual liquid remaining in the shallow vessel at the liquid level 102. This residual liquid gets churned up and refreshed with each refilling and does not stagnate.

Figure 13 is a sectioned end view A-A selected from figure 7 of the present invention and is included to more dearly illustrate the size and significance of the lagoon-like air tunnel 22. The view shows the prior art sectioned shallow vessel 1 accommodating a tub 20 which is raised up on pads 6 which are approx. lOmm thick and spaced apart so as to create a void or lagoon-like long air tunnel above the shallow sump 4. The long air tunnel is transient in that it only develops to achieve its maximum height of approx.

lOmm as liquid in the shallow vessel is wicked up into the bottom of the tub and consumed by the plant or plants.

Prior Art

Figure 6 shows an exploded perspective view of one example of the prior art, where the prior art shallow vessel 1 or tray is the same as that described for the present invention to which is added a prior art bistable liquid level control device 800 in this case an AQUAvalve5. Both items being supplied commercially by AutoPot (Global) Ltd. There is a halfmoon socket 806 which has a dual role, as it serves to both anchor the device to the shallow vessel or tray, by way of engaging with the TEE spigot 11, and to function as a breather, there being a horizontally communicated aperture (not shown) inside the top of the socket which communicates with the uppermost region of the first chamber inside the device.

Figure 14 is an end view section showing how the prior art is not able to produce a lagoon-like long air tunnel for liquid to disperse into to achieve the two sought after benefits -without raising the plant tub up on pads and adding also wicking pads, i.e., the plant tub occupies the space needed to create the long air tunnel.

Figure 15 is an exploded view of the items needed to assemble a custom manufactured version of the present invention, where the shallow vessel la has raised pads 5a as an integral feature of a single piece thermoplastic injection moulding. Between which the shallow sump 4a has been extended to a cruciform shape wherein two thicker, simpler wicking pads 7a are placed to simplify the wicking feature -compare with fig 2. This is the delayed action automatic watering assembly in its simplest form, and this may be compared directly with figure 6 the prior art which is not able to delay the onset of rewatering.

Referring again to the comparison between the figures 13 and 14 it will be self-evident to those skilled in the art that the essential long air tunnel could for example be created by recessing the bottom of the plant tub with a groove running from one side to the other. And installing the tub -without employing the spacer pads -so that it presents a long air tunnel aligned to the valve zone in the shallow vessel or tray. But this would require newly manufactured plant tubs with additional features to cater also for the wicking pads so that the final compound shape of the bottom of the plant tub or pot would not be compatible with the flat sheet of coated nonwoven root control fabric which is often employed for growing particular plant species. Further it is evident that the shallow sump could in principle be dispensed with, since the long air tunnel provides the primary catchment for liquid escaping from the valve zone. However, the sumps already exist in the million or so sets of watering assemblies that are in current use and the sumps are useful for collecting debris and retaining it rather than have it circulating around the shallow tray each time it is refilled. Over time these systems accumulate organic and inorganic matter which tends to clump together along with the inevitable algae that grows in the supply tank, the hoses and the shallow trays.

One purpose of the present invention is to extend the serviceable life of the existing universally adopted trays and tubs through adaptation, to achieve a more environmentally friendly outcome with healthier and more prolific plant growth for as diverse a range of plant species as possible Figure 16 shows a second embodiment, as compared with figure 2, where the wicking material would be in the form of at least one larger stiff porous spacer pad 6a, for example 10mm thick, having mechanical integrity so as to support the mass of a tub and mature plant without crushing down. And possess a capillary action throughout its extent, capable of elevating a liquid to at least 20mm in elevation, for example constructed from loose bundled end grain Balsawood or material with similar mechanical strength and wicking properties.

In this instance both the plain spacer pads 6 (fig 2), to raise the plant tub 20 (fig 7), and the compressible wicking pads 7 are not required. The stiff porous spacer pads run the extent of the growing zone on either side of the long central shallow sump 4. This is a simpler arrangement as compared with figure 2. And because the stiff porous spacer pads extend underneath a greater number of slitted apertures, in the base of the plant tub or pot, there are more opportunities for liquid to be conducted into the plant tub, which is helpful when the thin flat sheet (0.35mm thick) of custom-coated micro-porous root control fabric is employed as this has been shown to reduce the rate of liquid transfer from the shallow vessel through the wicking means and up into the plant tub.

Figure 17 shows a third embodiment, as compared with figures 2 and 16, where a skeleton support frame 30 is employed on each side of the long central sump 4 in the growing zone of a shallow vessel. Each frame is rectangular and has a run around peripheral thin wall 31, on the outside of which are six perpendicular stand-off thin walls 32 used for positioning within the growing zone of the shallow vessel. Inboard from each end of the run around frame there are cross-member thin walls 33. Together the outer frame wall and the cross-member walls define an elongate pocket 34 which accommodates a compressible elongate wicking pad 7b. The features also support the gross mass of a plant tub and mature plant.

The elongate wicking pads have a capillary action capable of elevating a liquid to at least 20mm in height. The support frame may have an optional cut-out 35 to facilitate the free movement of liquid. In this embodiment a wider range of wicking material choices are available to the designer ranging from soft nonwovens to semi-rigid sponges and open cell foams, so long as in each case the wicking function is capable of elevating a liquid to at least 20mm elevation. There is a wider choice also of fabrication methods, for example the support frames might be plastic injection moulded.

In this instance, i.e., figure 17, both the plain spacer pads 6 (fig 2), to raise the plant tub 20 (fig 7), and the compressible wicking pads 7 are not required. The new support frames run the extent of the growing zone on either side of the long central shallow sump 4 so that the gross mass of the tub is more evenly supported, i.e., not simply in the four corner regions of the tub. This is a simpler arrangement as compared with figure 2. And because the wicking capability extends underneath a greater number of slitted apertures in the base of the plant tub or pot, (figure 18) there are more opportunities for liquid to be conducted into the plant tub which is helpful when the thin flat sheet (0.35mm thick) of custom-coated micro-porous root control fabric is employed as this has been shown to reduce the rate of liquid transfer from the shallow vessel through the wicking means and up into the plant tub.

Figure 17 can be compared to the prior art shown in figure 6 which most particularly is not capable of delaying the onset of rewatering once the minimum liquid level in the shallow vessel is achieved.

Further, in the case of new manufactured shallow vessels, there is the option also to integrate the load bearing features of the skeleton support framework into the shallow vessel itself thereby reducing the number of components. The load bearing walls having gaps for liquid access to the wicking pads.

Figure 18 is a plan view of a prior art square plant tub 20 showing a common radial array of sated apertures 21, sixteen in total, in the base through which irrigation water and air can pass from the tray into the growing medium inside the tub and vice versa. The illustration shows how the wicking material 7b can be seen through ten of the slitted apertures. This is the same as in the second embodiment in figure 16 where the stiff porous spacer pads 6a would be visible also through ten slitted apertures. This can be compared with the embodiment in figures 1 and 2 and in figure 15, where the shorter wicking pads 7 and 7a would be visible through approximately six slitted apertures (not shown].

For the present invention to operate efficiently a number of the slitted apertures span the wicking means and these principally facilitate the controlled upward conduction of liquid into the tub and these are referred to in the first foreshadowed claim as second openings in same. Those slitted apertures that are sited over the long sump 4 (within the dashed line lozenge shape) in the shallow vessel are referred to in the first foreshadowed claim as first openings in same and these serve two purposes namely, they enable liquid to flood into the base of the tub during the filling stage, and they enable air from atmosphere to pass into the basal region of the tub during the development of the transient air tunnel, i.e., during the delay period, so aerating the roots.

It may be understood that referring here to an assembled delayed action automatic watering assembly it will be evident that further modifications and variations including scale, materials and relative dimensions are possible without departing from the underlying principles of the invention and that all such modifications and variations should be considered within the scope of the present invention. And this to include; any tray configuration capable of accommodating more than one plant tub, pot, bag or the like watered by way of a bistable liquid level control device, mechanical or otherwise, the assemblies demonstrating the ability to delay the onset of watering as so described.

Claims (1)

1. CLAIM 1.C\I 15 C\I a)DELAYED ACTION AUTOMATIC WATERING ASSEMBLYA delayed action automatic watering assembly into which may be placed one or a number of plants comprises; a shallow vessel having at least one growing zone for the placement of at least one plant tub, pot, bag or the like and a valve zone, and where within said valve zone there is installed a bistable liquid level control device which can be connected to an external liquid source, and where said device opens in response to a minimum liquid level and closes in response to a maximum liquid level being achieved in the shallow vessel, and where the bottom of the plant tub, pot, bag or the like is installed at an elevated height, which height is above the height of a lowermost breather vent aperture projecting from the bistable liquid level control device, such that as liquid from an external source passes through the bistable liquid level control device into the shallow vessel the shallow vessel fills to a maximum liquid level, which level floods a lowermost region of the plant tub, pot, bag or the like principally by way of first openings in same, and where liquid is removed from the shallow vessel by the plant or plants until the liquid level reduces to be close-by the bottom of the plant tub, pot, bag or the like, where upon further liquid is conveyed from the shallow vessel to the basal region of the plant tub, pot, bag or the like by way of at least one wicking means disposed between said items principally by way of second openings in same, so as to reduce the liquid level thereby creating a transient air tunnel, communicated to atmosphere, underneath said plant tub, pot, bag or the like for aeration of the growing medium contained within, principally by way of said first openings in same, the duration of said wicking process generally defining the delay period being sought, and where as a consequence of the wicking process the liquid level in the shallow vessel reduces, progressively increasing the depth of the transient air tunnel so that when the liquid level has reduced to a predetermined minimum, to initiate the onset of refilling said tunnel is at a maximum and serves as a lagoon-like extension to the said valve zone to accommodate displaced liquid from the valve zone caused by liquid escaping from underneath the liquid level control device, so that the liquid escapes more readily as though the valve zone were larger, which action improves the operation of the liquid level control device.