GB2105562A - Drip dispensing apparatus - Google Patents

Abstract

Apparatus for dispensing liquid at a constant drip rate for use in watering plants, by maintaining a constant head of water comprises an open-ended container 1 which is inverted into an open-topped bath 4 above an aperture 7 through which a wick 8 leads to the plant growing medium to be watered. The container 1 is a close fit in the bath 4 except at a local deformation 5 in the bath wall which exposes the surface of liquid to atmospheric pressure. An aperture 6 in the wall of the container 1 can be aligned with the deformation 5 by rotating the container so that the uppermost extent of the aperture exposed defines the equilibrium depth of liquid in the bath under atmospheric pressure, which is the effective head above the wick 8. The aperture 6 has an upward extent that varies about the periphery of the container, thereby allowing the head of liquid to be varied by rotating the container. <IMAGE>

Description

SPECIFICATION Drip dispensing apparatus This invention relates to drip dispensing apparatus.

There are occasions when it is required to dispense a liquid at a substantially constant drip rate, e.g., for the purpose of watering or liquid feeding plants. Generally such drip dispensing apparatus has comprised a container for the liquid and wick or valve means whereby the liquid can flow from the container as a series of drips.A disadvantage with such known drip dispensing apparatus is that either the rate of drip of the liquid does not remain constant but gradually slows down and eventually stops due to the liquid container gradually emptying and the head of liquid therein thus gradually decreasing, or means has to be provided for maintaining the level of the liquid in the container substantially constant such as by connecting the container to a suitable water supply and providing ball or other suitable valve means for controlling the flow of water from the water supply into said liquid container so as to maintain a predetermined head of liquid therein.

Thus it has been the case either that it has not been possible to maintain a substantially constant drip rate or that more elaborate and expensive measures have to be taken to maintain a constant drip rate such as by providing means for maintaining a constant head of liquid in the liquid container.

The present invention has as its object to provide drip dispensing apparatus which is simple and inexpensive to produce, which does not require any elaborate valve or like means for maintaining a constant head of water and which is capable of sustaining a substantially constant drip rate.

The present invention provides a drip dispensing apparatus for liquids, comprising a liquid container, at least one opening in said container, an open-topped bath adapted to receive that part of said liquid container having said at least one opening therein so that said at least one opening opens at an intermediate level within said bath and so that at least part of the surface of the liquid in said bath when the apparatus is in use will be open to atmosphere, whereby to determine the level of the liquid in the bath, and at least one aperture in said bath below said liquid level therein. If desired or necessary means may be provided for controlling the flow of liquid through said at least one aperture so that the liquid will issue from said aperture at a substantially constant drip rate.

The invention will be more particularly described with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a sectional elevation of one embodiment of drip dispensing apparatus according to the present invention, and Figure 2 is a plan view of the drip dispensing apparatus shown in Figure 1.

Referring to the drawings it will be seen that the drip dispensing apparatus illustrated therein comprises a cylindrical liquid container 1 one end 2 of which is closed and the other end 3 of which is open, the open end 3 being received within an open-topped bath 4. The open-topped bath 4 is of the same internal diameter as the external diameter of the cylindrical container 1 so that the cylindrical container 1 is a close fit within the open-topped bath 4 except at one or more radial positions 5 where the bath is opened to atmosphere by either locally reducing the wall thickness of the peripheral wall of the bath 4 or by locally deforming the peripheral wall of the bath 4 radially outwards, whereby the surface of liquid in the bath 4 will be exposed to atmosphere.The level that liquid from the liquid container 1 will attain in the bath 4 is determined by the height within the bath 4 at which the container 1 opens.

Thus this level can be adjusted by simply adjusting the level of the mouth of the container 1 within the bath 4. Preferably, however, the liquid container 1 is inserted into the bath 4 so that the open end of the container is in engagement with the bottom of the bath 4 and one or more apertures 6 is provided in the end 3 of the liquid container 1 , the or each said aperture 6 extending partially around the periphery of the container 1 and extending from the edge of the open end 3 of the container 1 progressively further in the axial direction for a distance less than the depth of the bath 4. With such an arrangement the liquid level in the bath 4 can be varied by rotating the liquid container 1 relative to the bath 4 so as to vary that part of the or each aperture 6 which is aligned with the radial portion 4 of the bath which is open to atmosphere.By so varying the level of the liquid in the bath 4 the head of liquid in the bath 4 can be varied and hence so can the drip rate of the liquid. If desired stop means, not shown, may be provided which cooperates with the or an aperture 6 to limit the angular extent through which the liquid container 1 can be rotated. Such stop means may, for example, comprise a protuberance in the bottom of the bath 4 in a position in which it will be engaged by the ends of the aperture 6 as the container 1 is rotated from the limit of its travel in one direction to the limit of its travel in the other.

Provided in the bottom of the bath 4 is a cylindrical aperture 7 through which extends a wick 8, although it will be understood that if desired the wick 8 can be dispensed with or can be replaced by any suitable valve means which will allow a liquid to issue therethrough at a required drip rate. It has been found that if the size of the aperture 7 is properly related to the size of the bath 4, the liquid level within the bath 4 and the surface area of the bath which is open to atmosphere, then liquid from the container 1 will issue from the aperture 7 in drips without the necessity for any wick or valve means. However, the said criteria appear to be somewhat critical so that small changes in operating conditions can easily affect the proper working of the apparatus and for this reason it is preferred to use a wick or valve in conjunction with the aperture 7.As will be seen the aperture 7 and the wick 8 are provided in that part of the bath 4 which is within the liquid container 1. Surprisingly it has been found that the head of liquid acting on the wick 8 is apparently the head of the liquid contained in the bath 4 and not the head of liquid in the liquid container 1 whether the wick 8 is provided in the bath 4 in such a position that it is within the liquid container 1 or outside the liquid container 1. Locating the wick 8 within the liquid container 1 enables the radial portion 5 of the bath 4 which is open to atmosphere to be klept to a minimum, thus facilitating a compact arrangement. Trial and error will quickly show the size of the aperture 7 and the size and composition of the wick 8 which will be necessary in any particular case to provide a required drip rate.

If the liquid being dispensed contains suspended solids, e.g., is ordinary tap water from a hard water area, then it is possible that the wick 8 will become blocked or clogged with such solids and will require periodic rinsing or cleaning. To facilitate such rinsing or cleaning of the wick 8 and to avoid the necessity for the wick to be removed from and replaced in the aperture 7 the short length of wick shown may be replaced by a very much longer length sufficient to enable a long enough length to be withdrawn through the aperture 7 as can readily be rinsed, e.g., under a tap, whilst leaving an inner end of the wick still within the container 1 or bath 4. Said inner end of the wick may be provided with a knot therein or other suitable stop means to prevent it being withdrawn through the aperture 7.After rinsing, the wick is redrawn back through the aperture 7 so that only a short length thereof protrudes from the aperture 7.

Depending axially downwards from the underside of the bath 4 is a ferrule 9 adapted to receive a pole or cane, e.g., a plastics pole for supporting a plant or which can be inserted into the soil or other growing medium in which a potted plant is growing. Many climbing plants such as ivies and vines are best grown on a support which is covered either with moss or with a foamed plastics material or the like, the moss or other material being maintained moist to maintain humidity around the plant or to enable the plant to absorb moisture by way of aerial roots. With such an arrangement the drip dispensing apparatus of the present invention can be positioned on top of the plant supporting pole so that the liquid from the container 1 will drip at a required rate onto the moss, foam plastics or other material so as to maintain the said material in a moist condition.

It will be understood that various modifications can be made to the drip dispensing apparatus illustrated without departing from the scope of the present invention. For example the liquid container 1 has been shown as a cylindrical container although it will be understood that it could be any other suitable form of closed container, e.g., such as a suitable bottle or other container, e.g., of plastics or other suitable material, which has a necked opening, the bath 4 being adapted to receive said necked opening in the manner hereinabove described. If desired the necked opening of said container could be externally screw-threaded and the bath 4 could be internally screw-threaded so as to threadedly receive the necked opening of the container therein. For example the container 1 could be a blow moulded plastics bottle of the kind now commonly being used for soft drinks or the like.

It has been found that with apparatus of the kind illustrated in the drawings and with the wick 8 only a loose sliding fit in the cylindrical aperture 7, liquid in the container 1 will issue from the lower end of the wick 8 at a constant drip rate and that such drip rate is variable within limits by varying the liquid level within the bath 4 so as to vary the head of the liquid in the bath 4. It will thus be appreciated that the present invention provides extremely simple but effective drip dispensing apparatus which avoids the disadvantages of known drip dispensing apparatus as hereinbefore described.

Claims (14)

1. A drip dispensing apparatus for liquids, comprising a liquid container, at least one opening in said container, an open-topped bath adapted to receive that part of said liquid container having said at least one opening therein so that said at least one opening opens at an intermediate level within said bath and so that at least part of the surface of the liquid in said bath when the apparatus is in use will be open to atmosphere, whereby to determine the level of the liquid in the bath, and at least one aperture in said bath below said liquid level therein.

2. A drip dispensing apparatus as claimed in Claim 1, comprising means for controlling the flow of liquid through said at least one aperture so that the liquid will issue from said aperture at a substantially constant drip rate.

3. A drip dispensing apparatus as claimed in Claim 2, wherein the means for controlling the flow of liquid through said at least one aperture comprises a wick extending through said at least one aperture.

4. A drip dispensing apparatus as claimed in Claim 3, wherein the wick is of a length sufficient to enable such a length to be withdrawn through the aperture as can readily be rinsed whilst leaving an inner end of the wick still within the bath.

5. A drip dispensing apparatus as claimed in any one of the preceding claims wherein the said container is an open-ended container, the open end thereof being received within the open-topped bath.

6. A drip dispensing apparatus as claimed in Claim 5, wherein at least the said end of the container is cylindrical.

7. A drip dispensing apparatus as claimed in Claim 6, wherein the said end of the container is a close fit within the open-topped bath except at one or more radial positions where the bath is opened to atmosphere by either locally reducing the wall thickness of the peripheral wall of the bath or by locally deforming the peripheral wall of the bath outwardly.

8. A drip dispensing apparatus as claimed in Claim 5 wherein the open end of the container is in engagement with the bottom of the bath and one or more apertures are provided in the end of the container, the or each said aperture extending partially around the periphery of the container and extending from the edge of the open end of the container in the axial direction for a distance less than the depth of the bath.

9. A drip dispensing apparatus as claimed in Claim 7 and in Claim 8 wherein the or each aperture provided in the end of the container extends from the end of the container in the axial direction for a distance that varies progressively with the extent of the aperture around the periphery of the container, whereby the liquid level maintained in the bath when the apparatus is in use can be varied by rotating the container relative to the bath so as to vary that part of the or each said aperture which is aligned with the radial portion of the bath that is open to atmosphere.

10. A drip dispensing apparatus as claimed in Claim 9 wherein stop means are provided which cooperate with the or a said aperture to limit the angular extent through which the container can be rotated relative to the bath.

11. A drip dispensing apparatus as claimed in any one of Claims 5 to 10 wherein the aperture in the bath is provided in a part of the bath that lies below or within the open end of the container.

12. A drip dispensing apparatus as claimed in any one of Claims 1 to 8 wherein the container is screw-threadedly received in the bath.

13. A drip dispensing apparatus as claimed in any one of the preceding Claims including a downwardly depending female adapted to receive a pole or cane to support the apparatus above a growing medium for a plant.

14. A drip dispensing apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.