GB2285974A - Filter, particularly for pond water - Google Patents

Abstract

A filter suitable for a pond comprises a container (2) housing a mass of filter material (3). A tray (8) is located at the upper end of the container and substantially closes the upper end. Raw water is delivered to the tray by suitable means, e.g. a pump via a riser (7). Apertures (12) are provided in the tray at a predetermined distance above the bottom surface thereof such that when the water level within the tray rises above the level of the apertures the water will flow from the tray into the filter material (3) thereby maintaining a constant water level in the tray. A layer of growing medium (17) is located within the tray supported on a barrier (16) located at a level above that of the apertures whereby plants may be planted in the growing medium and their roots may extend into the portion of the tray below the level of the apertures to remove nutrients and/or other minerals from the water flowing through the tray. <IMAGE>

Description

FILTER, PARTICULARLY FOR POND WATER This invention relates to a filter and, in the preferred embodiment, provides a filter particularly suitable for removing suspended and/or dissolved minerals and nutrients from pond water.

The term "filter" as used herein means a device through which water is passed in order to remove at least one dissolved or suspended impurity from the water. It should be noted that the term is not limited to devices in which the water is forced to pass through a porous material which constitutes a physical barrier for the purposes of removing the impurity.

Filters for the purpose of removing minerals and/or nutrients from pond water are well known.

Typically, such filters comprise a tank which is filled with a suitable filter material which provides a large surface area to support a large colony of micro-organisms.

As the water passes through the filter material the microorganisms utilize the nutrients and other minerals to grow.

In this process, certain undesirable materials, notably nitrates and phosphates, are removed from the water.

Whilst filters of the above described type are well known, they have, in the prior art, suffered from the disadvantage that they are of substantial size and generally unpleasant appearance. In general, the filter material will be housed within a cuboid moulded plastics box which must either be located a substantial distance from the pond to avoid detracting from the visual appearance of the pond, or must be located within a housing built for that purpose adjacent the pond.

The present invention provides a pond filter in which the upper surface of the filter is specifically designed to support plant life. Accordingly, the upper surface of the filter may be used to grow plants which in themselves are desirable and which, at the same time, disguise the appearance of the filter. In a particularly preferred embodiment of the filter the container housing the filter material is in itself a decorative container, for example a pot of reconstituted stone, terracotta or similar material. By this means, an effective filter which is pleasing in appearance can be provided. Further, the presence of the plants, in the preferred embodiment, assists in removal of nutrients and minerals from the water.

Accordingly, one aspect of the present invention provides a filter suitable for a pond, the filter comprising a container housing a mass of filter material; a tray located at the upper end of the container and substantially closing the upper end of the container; means for delivering raw water to the tray; apertures in the tray at a predetermined distance above the bottom surface thereof such that when the water level within the tray rises above the level of the apertures the water will flow from the tray into the filter material; and a layer of growing medium located within the tray and extending to a level above that of the apertures whereby plants may be planted in the growing medium and their roots may extend into the portion of the tray below the level of the apertures to remove nutrients and/or other minerals from the water flowing through the tray.

In a particularly preferred embodiment of the invention a means for supplying water to the tray comprises a riser which extends through the filter material.

Accordingly, both inlet and outlet connections from the filter may be located adjacent the bottom of the container, in which case they will be relatively inconspicuous to casual observers of the filter.

Additionally or alternatively the inlet pipe is preferably located within the outlet pipe so that the inlet and outlet pipes are generally co-axial and accordingly only a single pipe appears to extend from the pond to the filter.

In a particularly preferred embodiment of the invention a barrier is provided between the lower surface of the tray and the growing medium whereby the growing medium is supported on the barrier and a chamber is defined below the barrier so that the roots of the plants can grow through the barrier into the chamber to form a mesh through which the water flows.

The invention will be better understood from the following description of a preferred embodiment thereof, given by way of example only, reference being had to the accompanying drawings wherein: Figure 1 is a schematic vertical cross-sectional view through a preferred embodiment of the invention; Figure 2 is a side view, partly in section, showing a part of the embodiment of Figure 1; and Figure 3 is a schematic perspective view of the arrangement of Figure 2.

Referring firstly to Figure 1, the illustrated filter 1 comprises a container 2 which houses a mass of filter material 3. The container 2 may be of any suitable form, but is preferably decorative. To this end, the container may be a pot of reconstituted stone, simulated stone, terracotta, or the like. The filter material 3 may be of any convenient known form. As will be appreciated by those skilled in the art there are a wide range of materials which are capable of supporting colonies of micro-organisms for the purposes of removing nutrient from water.

The container includes an outlet 4 from which water flows to be returned to the pond from which it has previously been removed, and an inlet 5 for receiving water from the pond.

The inlet 5 is connected to a horizontal feed pipe 6 which extends to the centre of the container and is there connected to a riser 7 which extends vertically upwardly to a tray 8 located adjacent the upper end of the container. The tray 8 may be supported on the riser 7 or on the filter material 3, but is preferably supported on one or more ledges provided for that purpose by the container 2.

In the illustrated embodiment of the invention the container is generally circular in cross-section at the mouth thereof and accordingly the tray is similarly circular so as substantially completely to fill the mouth of the container. The tray comprises a base 9 and an upstanding peripheral wall 10. Overflow holes 11 are provided in the peripheral wall to prevent the level of water within the tray rising above the level of the overflow holes. Additionally, drainage holes 12 are provided in the tray for permitting water which has entered the tray via the riser to flow out of the tray and over the surface of the filter material. The arrangement of drainage holes 12 in the preferred embodiment of the invention is more clearly shown in Figure 3. It will be noted that the tray is divided into a multiplicity of sectors 13 by hollow ribs 14 which extend radially from a water distributing hub 15 to the peripheral wall 10. Each rib 14 includes, along the upper edge thereof, a multiplicity of drainage holes 12.

Whilst in the illustrated embodiment of the invention four ribs divide the tray into four sectors, it will be appreciated that other numbers or ribs/sectors are possible within the scope of the invention.

Referring again to Figures 1 and 2, a barrier 16 is supported atop the ribs 14. The barrier may be of any suitable material, for example a mesh or foam material.

The barrier 16 supports a growing medium 17, for example, soil, a soil-based compost, or a soilless compost. In the preferred embodiment of the invention the barrier is sufficiently rigid to support the growing medium in manner to define a multiplicity of chambers 18 each defined by a portion of the barrier, a portion of the base 9 and two of the ribs 14.

In use, suitable plants are planted in the growing medium and water is pumped continuously into the inlet 5 to travel along pipe 6 and riser 7 and thence outwardly through hub 15 into the chambers 18. Initially, the soil will be wetted because the lower surface of the soil will be substantially at the water level within the tray as defined by the position of the drainage holes 12.

The plants will, accordingly, grow vigorously and after a short period the roots of the plant will penetrate the barrier to enter the chambers 18. The roots will tend to form a dense mat of feeding roots within the chambers 18 and will extract from the water located in these chambers nutrients (typically nitrates and phosphates), minerals and trace elements required to sustain plant growth. The water, having passed through the chambers 18, will flow downwardly through drainage holes 12 to be acted on by the biological filtration process in conventional manner.

It will be appreciated that the invention may be embodied as a garden feature of considerable aesthetic appeal. By chosing a suitably attractive container and, effectively, covering the top of the container with plant growth, a pleasant feature may be formed from a device which, heretofore, has been unpleasant in appearance.

Also, the presence of the plant growth will assist in removing impurities from the water and will be particularly effective in removing certain impurities, for example trace elements, which are normally unaffected or substantially unaffected by biological filtration techniques.

Claims (13)

1. A filter suitable for a pond, the filter comprising a tray; means for delivering raw water to the tray; apertures in the tray at a predetermined distance above the bottom surface thereof such that when the water level within the tray rises above the level of the apertures the water will flow from the tray; and a layer of growing medium located within the tray and extending upwardly from a barrier located at a level above that of the apertures whereby plants may be planted in the growing medium and their roots may extend into the portion of the tray below the level of the apertures to remove nutrients and/or other minerals from the water flowing through the tray.

2. A filter according to claim 1 wherein the tray is located at the upper of a container and substantially closes the upper end of the container.

3. A filter according to claim 2 wherein the means for supplying water to the tray comprises a riser which extends through the container and water flowing the apertures in the tray enters the container for collection by the container.

4. A filter according to claim 3 wherein an inlet connection to the riser and an outlet connection from the interior of the container are located adjacent the bottom of the container.

5. A filter according to claim 4 wherein the inlet and outlet pipes are generally co-axial.

6. A filter according to any preceding claim wherein the container is substantially filled with a filter medium.

7. A filter according to any preceding claim wherein the barrier is of a foam or mesh material.

8. A filter according to any preceding claim wherein the growing medium comprises soil or a soil based compost or a soilless compost

9. A filter according to any preceding claim wherein the tray is formed with a plurality of hollow ribs extending upwardly from the lower surface of the tray and the apertures are provided in the ribs.

10. A filter according to claim 9 wherein the apertures are in the upper surface of the ribs.

11. A filter according to claim 9 or claim 10 wherein the barrier is supported on the ribs.

12. A filter according to any preceding claim in combination with a pump for supplying water to the tray whereby the tray, the pump, and any container housing the tray and the pump form a self-contained filter assembly.

13. A filter substantially as hereinbefore described with reference to the accompanying drawings.