WO1989011788A1

WO1989011788A1 - Plant pot

Info

Publication number: WO1989011788A1
Application number: PCT/GB1989/000625
Authority: WO
Inventors: Brian Arthur Staley
Original assignee: Brian Arthur Staley
Priority date: 1988-06-09
Filing date: 1989-06-05
Publication date: 1989-12-14
Also published as: EP0419543A1; AU3770089A; GB8813716D0; GB9026543D0; GB2237965A; GB2237965B; GB2219480A

Abstract

A self watering plant pot has an inner container (1) for the plant (3) and its growing medium. The container (1) floats in buoyancy liquid (27) in a further container (4). A valve diaphragm (18) is connected to both containers (1, 4) at their bottom walls (17, 9) to lead water (6) for the plant from an outer, reservoir container (5) through the buoyancy container (27) and into the inner container. With water loss from plant and growing medium, the inner container rises and admits water through the valve, thus constantly maintaining the pre-set weight of water/plant/growing medium.

Description

PLANT POT

Field of the Invention

The present invention relates to a plant pot which is adapted for controlled watering of growing medium and a plant within the pot.

Such plant pots are known as self-watering pots. As used herein the term plant pot is defined to mean any vessel in which a plant can be grown such as a flower pot, a seed tray, a hanging basket, a wall container for plants, a tub or trough for containing many small plants or a few large plants. Background of the Invention

Self-watering pots utilizing wicks for supplying water by capillary action from a reservoir to the growing medium are known. They are not easy to control - as regards the rate of watering - and are little improvement on standing a conventional plant pot in a tray of water.

It is known from British Patent Specifications No's: l 192 424, 1 127 936 and 1 533 184 to control flow of water to plant pots in accordance with their weight. When they dry out - and require watering - they weigh less and are spring biassed in the first two specifications and balance-arm biased in the third to open a valve to allow water to flow from a reservoir to the plant pot which becomes heavier and hence closes the valve again.

These arrangements involve varying degrees of mechanical complexity.

British Patent Specification No: 827,894 describes a livestock drinking trough having an outer tank and an inner tank. The latter is pivoted at one end and carries on its underside at the other end a pad for occluding a water supply orifice beneath it. When water is drunk from the inner tank, it floats in the outer tank, with the pad rising off the orifice. This allows water into the outer tank. The inner tank has an aperture at its pivoted end - which aperture therefore remains at a substantially constant height. When the water level rises in the outer tank, water flows -through the aperture so that the inner tank is no longer so buoyant. As the water level in the inner tank approaches that in the outer tank, the former sinks under its own weight to occlude the supply orifice. There is no suggestion that this apparatus could be adapted for watering plant pots. in the livestock trough, the height of the water in both the outer and the inner tank is controlled by the height of the aperture in the inner tank sidewall. The height of the water in the inner tank is lower by an amount related to the weight of the inner tank and its displacement. The Invention

The object of the present invention is to provide an improved plant pot utilizing buoyancy and flotation movement of an inner container to control flow of water to growing medium, which is at the same time readily controllable to accommodate variations in the quantity and density of growing medium used.

According to the invention there is provided a plant pot for containing growing medium and a plant, the pot comprising:- an inner container for the plant and its growing medium; a buoyancy liquid container adapted to have the inner container and a buoyancy liquid arranged within it for flotation of the inner container on water loss from the growing medium; and valve means adapted and arranged to open and admit water for the plant to the inner container without mixing with the buoyancy liquid when the inner container floats. T e mass of the growing medium is readily compensated for by adjusting the average height of the buoyancy liquid. In practice with the growing medium reasonably dry on initial potting of the plant, buoyancy liquid is added until the inner container just floats. Thereafter watering will be automatic. Should the growing medium be insufficiently watered, more buoyancy liquid can be added to provide more buoyancy to float the weight of wetter growing medium and vice versa.

Normally the buoyancy medium will be water, but in special circumstances, such as a heavy plant, a denser liquid such as brine can be used. It does not poison the plant since it does not mix with the water.

Although positioning of the valve means externally of the pot can be envisaged it is preferably within the buoyancy liquid container. For this, it preferably comprises an impermeable, flexible member sealingly attached to both the inner container and the buoyancy liquid container and arranged to conduct the water for the plant from without the buoyancy liquid container, through the buoyancy liquid and into the inner container.

Conveniently, the flexible member is a diaphragm having a first endless edge and a second endless edge, the first endless edge being sealingly connected to a wall - preferably a bottom wall - of the inner container, the second endless edge being sealingly connected to a wall - preferably a bottom wall - of the buoyancy liquid container, the said walls being perforate within the extent of their sealing connections to the said endless edges for passage of water for the plant on floating of the inner pot and the perforation in the said wall of one of the said containers being arranged to be occluded on sinking of the inner container when its growing medium is wetted by the water. The said perforation may be occluded by the said wall of the other container. Advantageously the said wall having the perforation to be occluded or the other said wall opposite the perforation carries a sealing ring, the sealing ring being compressed for sealing on sinking of the inner container. Conveniently the sealing ring is a portion of the flexible member. In the preferred embodiment, the flexible member includes a tubular extension which can be passed through the said aperture to be occluded for fitting of diaphragm to the container having the aperture to be occluded and which is severable at the aperture after fitting. The tubular extension may not be severed and may be used as a connection to a water supply pipe.

Alternatively the flexible member is a pipe connected to the inner container at an aperture therein and to the buoyancy liquid container at an aperture therein and having a portion between the said connections which is occluded by compression between the containers under the weight of the wetted growing medium on sinking of the inner container.

To provide sensitivity, that is operation of the valve means over a reasonably small change in growing medium weight, the inner container and the buoyancy liquid container are preferably a wide fit within each other, providing a wide ring of buoyancy water around the inner container. However too wide a ring causes excessive diameter of the buoyancy water container or too small a diameter of the inner container. Where the ring of buoyancy water is of constant width and the containers are circular, the width is conveniently within the range 1% to 4% preferably 1.5% to 2.5% of the outside diameter of the inner container. The preferred embodiment includes means interengaging the inner container and the buoyancy water container to limit flotation movement of the inner container upwardly of the buoyancy liquid container. The interengaging means may be rims of the inner and buoyancy liquid containers. Preferably, the interengaging rims are down-turned rims arranged outwardly of the upper edges of side walls of the containers, the rim of the buoyancy liquid container having a lip on its outer side and the inner container having a lip on its inner side, the lips engaging on permitted upwards flotation of the inner container to expose a normally covered portion of the rim of the buoyancy liquid container. The Drawings

To help understanding of the invention, two embodiments and variants of the invention will now be described by way of example and with reference to the accompanying drawings in which:-

Figure 1 is a perspective view of a first plant pot according to the invention;

Figure 2 is a cross-sectional side view on a medial plane of the port of Figure 1;

Figure 3 is an enlarged scrap cross-sectional view of the valve diaphragm of the pot;

Figure 4 is a similar view of a buoyancy liquid filling aperture (not shown in Figure 2); Figure 5 is a view similar to Figure 2 of a variant of the pot without an outer container, but with a tube feed;

Figure 6 is a view similar to Figure 2 of another plant pot according to the invention. The Preferred Embodiment Referring first to Figures 1 to 4 , the plant pot has an inner container 1, with growing medium 2 and a plant 3, a buoyancy liquid container 4 and a reservoir container 5 for water 6 with which the plant is to be watered. The buoyancy liquid container 4 is a force-fit with lugs 7 moulded inside the reservoir container. The force fit avoids the buoyancy liquid container floating in the reservoir liquid, when the reservoir container is full of water 6. The buoyancy liquid container has bosses or webs 8 to space its bottom wall 9 from the bottom wall 10 of the reservoir container and allow water to flow there. The inner container 1 is a loose, but close, fit in the buoyancy liquid container 4. For instance the gap 11 between them is 4mm for a nominal 200mm diameter of the inner container. The latter is centered by webs 12 moulded inside the buoyancy liquid container 4. The upper edges of these two containers 1,4 interengage at respective turned-down rims 13,14. The rims are a sliding fit. The rim 13 of the container 4 has an external lip 15; whilst the rim 14 of the container 1 has an internal lip 16. In the position shown in Figure 2, the valve to be described below is closed and the bottom edges of the rims are flush. In the event of the inner container 1 rising, the lips inter-engage, exposing a band 13' of the rim 13. The containers are conveniently of moulded polypropylene, which allows snap-fitting of them together, with riding of the rims over each other.

Sealingly connected to the bottom wall 17 of the inner container 1 and the bottom wall 9 of the buoyancy liquid container 4 is a valve diaphragm 18. These walls have respective lips 19,20. The diaphragm 18 is of elastomer and has endless beads 21,22 which engage with the lips and seal the diaphragm to the bottom walls. A central passage 23 in the diaphragm extends through an aperture 24 in the bottom wall 9, whilst the inner container's bottom wall 17 has a plurality of small perforations 25 within the extent of its lip 19. Thus in use water can pass from the reservoir 5, through the passage 23 and the perforations 25 - filling the central space 26 with the diaphragm - and into the inner container. This water cannot mix with buoyancy liquid 27 between the inner container 1 and the buoyancy liquid container 4.

Around the passage 23 on the top surface of a sealing ring 28 of the diaphragm, two grooves 29 are moulded which provide the sealing ring 28 with three concentric sealing ribs 30. The inner pot's bottom wall 17 has a flat 31 opposite the sealing ring 28 which sealingly engages the latter, when the inner container rests in its lowest position. In this position water cannot pass through the valve. in use, buoyancy liquid 27, in practice usually water, is present between the inner and the buoyancy liquid containers. When the growing medium dries, the inner container is buoyant and water 6 flows to the growing medium. This becomes heavier and the inner container then sinks once more, stopping further flow of water for the time being. In practice the valve peration is in effect a controlled leak.

Should the water 6 be expanded, this will be evident, by floating of the inner container until the lips 15,16 engage, when the band 13' of the inner container will be exposed. This may be coloured differently from the rim 14, to provide warning of the condition, namely that more water 6 needs to be added.

It will be appreciated that due to its inaccessibility, special means is required for fitting of the diaphragm 18. With the containers 1,4,5 dis-assembled, the diaphragm 18 can be fitted via its bead 21 and the lip 19 to the inner container 1. The diaphragm is moulded with an extension tube 32 - shown in outline in Figure 2. This is threaded through the aperture 24 in the container 4. The rims 13,14 and their lips 15,16 are engaged. Downwards pulling on the extension tube 32 engages the bead 22 of the diaphragm behind the lip 20. With the diaphragm thus installed, the tubular extension 32 can be cut off. Alternatively, as shown in Figure 4, in a variant without an outer container 5, water can be fed by a pipe 33 to the tube 32 and thence into the container 1 under control of the valve.

Referring back to Figure 2, a plurality of pots can be fed with water by dispensing with their outer containers 5 and standing them in a common tray of water. Alternatively the outer containers may be retained and be ruptured at a weak point 34. They can then be stood in and fed from a common tray. For subsequent independent use, the rupture can be repaired with a screw and 0 ring 35.

For filling of the buoyancy space between inner and buoyancy liquid containers 1,4, buoyancy liquid 27 is introduced through a filling port 36 in the rim 14 as shown in Figure 4. The rim 13 has a local indent 37 to allow the liquid 27 to flow freely. After filling, the containers may be twisted - slipping the diaphragm on the lips 20 - to minimize evaporation of the liquid 27.

If the pot is to be hung - and fed by the tube 32 - weakenings 38 in the rim 14 can be ruptured to allow a support cord or chain to be passed through this rim and through the rim 13 via moulded apertures 39 for support by a non-shown member engaging beneath the rim 13. Second Embodiment

Referring now to Figure 6, there is shown an alternative pot. It has an inner container 101, buoyancy liquid container 104 and a reservoir container 105 substantially the same as those of the Figure 2 embodiment. The diaphragm 18 is replaced by a tube 150. It is engaged by beads 151,152 with apertures 153,154 in the bottom walls of the containers 101,104 by means of severable extensions 155 in the manner of the diaphragm 18 and extension 32. A central portion of the tube 150 passes between ribs 156,157 on the bottom walls. When the inner container 101 sinks, it compresses and occludes the tube. In order to keep the tube located between the ribs, anti-rotation webs 158,159 are provided on the containers.

It is important that the gap between the inner container and the buoyancy liquid container be large enough for the valve to be sensitive. When the growing medium dries to a neutral buoyancy condition, the inner container will float on further drying. However a flotation movement results in fall in buoyancy liquid level with the result that the inner container does not float, with valve opening, as readily as it would if the gap were larger and the fall less. Nevertheless for a given pot size, the buoyancy volume available is in practice restricted because it occupies space which is useful either for growing medium or "watering" water.

Although the described embodiments are circular in plan cross-section, it should be noted that other shapes such as rectangular or other polygonal shapes, can be employed.

In use of plant pots of the invention, plant nutrient may be provided in the water for the plant. The growing medium may be peat or compost for conventional culture or aggregate or the like for hydroponic culture.

Claims

1. A plant pot for containing growing medium and a plant, the pot comprising:- an inner container for the plant and its growing medium; a buoyancy liquid container adapted to have the inner container and a buoyancy liquid arranged within it for flotation of the inner container on water loss from the growing medium; and valve means adapted and arranged to open and admit water for the plant to the inner container without mixing with the buoyancy liquid when the inner container floats.

2. A plant pot as claimed in claim 1, wherein the valve means comprises an impermeable, flexible member sealingly attached to both the inner container and the buoyancy liquid container and arranged to conduct the water for the plant from without the buoyancy liquid container, through the buoyancy liquid and into the inner container.

3. A plant pot as claimed in claim 2, wherein the flexible member is a diaphragm having a first endless edge and a second endless edge, the first endless edge being sealingly connected to a wall - preferably a bottom wall - of the inner container, the second endless edge being sealingly connected to a wall - preferably a bottom wall - of the buoyancy liquid container, the said walls being perforate within the extent of their sealing connections to the said endless edges for passage of water for the plant on floating of the inner pot and the perforation in the said wall of one of the said containers being arranged to be occluded on sinking of the inner container when its growing medium is wetted by the water.

4. A plant pot as claimed in claim 3, wherein the said perforation is occluded by the said wall of the other container.

5. A plant pot as claimed in claim 3 or claim 4, wherein the said wall having the perforation to be occluded or the other said wall opposite the perforation carries a sealing ring, the sealing ring being compressed for sealing on sinking of the inner container.

6. A plant pot as claimed in claim 5, wherein the sealing ring is a portion of the flexible member.

7. A plant pot as claimed in claim 6, wherein the sealing ring includes one or more annular sealing ribs and the opposite wall comprises a flat for occlusion contact with the sealing rib(s).

8. A plant pot as claimed in claim 7, wherein the occluded aperture is in the buoyancy liquid container and the flat is on the inner container, which latter includes at least one small water aperture around the plant.

9. A plant pot as claimed in any one of claims 3 to 8, wherein the diaphragm is of elastomeric material and includes a respective rib at each endless edge and the containers each include an endless lip for connection of the diaphragm thereto, each rib being resiliently engaged with its lip for sealing of the diaphragm to the containers.

10. A plant pot as claimed in claim 6, wherein the flexible member includes a tubular extension which can be passed through the said aperture to be occluded for fitting of diaphragm to the container having the aperture to be occluded and which is severable at the aperture after fitting.

11. A plant pot as claimed in claim 1 or claim 2, wherein the flexible member is a pipe connected to the inner container at an aperture therein and to the buoyancy liquid container at an aperture therein and having a portion between the said connections which is occluded by compression between the containers under the weight of the wetted growing medium on sinking of the inner container.

12. A plant pot as claimed in any preceding claim, including means interengaging the inner container and the buoyancy water container to limit flotation movement of the inner container upwardly of the buoyancy liquid container.

13. A plant pot as claimed in claim 12, wherein the inner container and the buoyancy liquid containers each have an interengaging rim to limit flotation movement of the inner container upwardly of the buoyancy liquid container.

14. A plant pot as claimed in claim 13, wherein the interengaging rims are down-turned rims arranged outwardly of the upper edges of side walls of the containers, the rim of the buoyancy liquid container having a lip on its outer side and the inner container having a lip on its inner side, the lips engaging on permitted upwards flotation of the inner container to expose a normally covered portion of the rim of the buoyancy liquid container.

15. A plant pot as claimed in claim 14, wherein the said normally covered portion is coloured differently from the rim normally covering it.

16. A plant pot as claimed in claim 13, claim 14 or claim 15 wherein the top surface of the down-turned rim of the inner container has a filling aperture for buoyancy liquid between the containers.

17. A plant pot as claimed in any preceding claim, including an outer, water reservoir container in which the buoyancy liquid container is engaged to prevent flotation thereof when the outer container is filled with water for the plant, the outer container and/or the buoyancy liquid container incorporating ribs to space these two containers and allow water in the outer container to flow to the valve means.

18-. A plant pot as claimed in any preceding claim wherein the inner container and the buoyancy liquid container are circular in horizontal cross-section and difference between the internal diameter of the latter and the external diameter of the former is within the range 1% to 4% of the external diameter of the former,