APPARATUS FOR THE REMOVAL OF SETTLED SOLIDS FROM BODIES

OF LIQUID

FIELD OF THE INVENTION

This invention relates to apparatus for the removal of settled solids from bodies of liquid, in particular water, in a procedure commonly referred to as sludge removal. The invention also relates to containers that embody such apparatus.

Applications to which apparatus according to the invention may be put are numerous and range from the removal of solid excreta and other solid materials from water employed in aquacultural equipment used in the culturing of aquatic species including fish and marine organisms, to water purification plants and chemical processing and production plants in which precipitated, flocculated or otherwise settled solids need to be separated from a body of liquid.

BACKGROUND TO THE INVENTION

There are numerous instances in which solids are generated in bodies of liquids, typically water, and many of them require that settled solids be removed, at least from time to time, from the bottom of a container. Typical of equipment used for this purpose is a conical or other convergent bottom to a container in which liquid is located. This configuration of the bottom to a container is particularly disadvantageous from the point of view that, in order to provide a suitable angle for the solids to slide down, generally accepted to be about 60 degrees to the horizontal, an appreciable height is normally required with the attendant cost of the equipment itself and also the space to house it. Such height imposes serious limitations on the capacity of a relevant container and, accordingly, generally increases the number of

containers that must be used in order to treat a predetermined quantity of liquid.

In published international patent application WO 2004/01776 in respect of which I am the inventor, it was proposed to use a series of parallel channels to collect the faeces of the aquatic species being grown in certain aquaculture tanks. The channels were of basically Vee-shape in cross- section with an enlarged gutter at the bottom of the Vee such that the bottom of the inclined walls of the Vee formed a restricted entrance to the gutter. The restricted entrance to each gutter was to be closed and opened by raising and lowering elongate closures into and out of contact with the convergent surfaces of the Vee. The proposal did not work effectively and it was abandoned because of difficulties in mechanically raising and lowering the elongate closures and obtaining an effectively closed passageway in the gutter through which the solids could be withdrawn.

OBJECT OF THE INVENTION

It is an object of this invention to provide apparatus for the removal of settled solids from bodies of liquids that does not require any appreciable height within the liquid container being serviced. The invention also relates to containers embodying such apparatus

SUMMARY OF THE INVENTION

In accordance with this invention there is provided apparatus for the removal of settled solids from bodies of liquids, the apparatus comprising a generally horizontal collection surface composed of a plurality of juxtaposed elongate channels each of which has downwardly convergent walls that terminate in a generally U-shaped gutter at the bottom of the channel and wherein an elongate closure is associated with an upper region of the U-shaped gutter, the apparatus being characterized in that each closure is tubular and

hydraulically or pneumatically inflatable in cross-sectional configuration between an inoperative condition in which at least a portion of the width of the gutter is open to allow solids to settle onto the bottom of the gutter and an operative condition in which the tubular closure is expanded across the width of the upper region of the gutter in order to close same and form, with a lower region of the gutter, a passageway for the longitudinal flow of liquid to flush settled solids from the gutter.

Further features of the invention provide for the generally horizontal collection surface to either form the bottom of a container in which settling of solids from a liquid, typically water, is to take place or, alternatively, for the generally horizontal collection surface to form part of apparatus for installation in a container to form a bottom to a settling compartment positioned above it; for a major portion of the width of the gutter to be open in the inoperative condition of the tubular closure to allow solids to settle onto the bottom of the gutter; for one end of the elongate tubular closure to be attached to a sleeve typically passing through an end wall of a container in which the apparatus is located, the sleeve holding the associated end of the closure in generally sealing association with an adjacent part of the upper region of the U-shaped gutter; for the closure to terminate short of the other end of the associated channel to provide an inlet to a corresponding end of the passageway when the closure is in its operative condition such that liquid contained in an associated container may enter the passageway at such end and flush settled solids in the gutter out at the opposite end thereof; and for one end of the closure to have an inlet for fluid under pressure for causing the closure to adopt an operative condition in response to fluid under pressure.

In one form of the invention the elongate closure is in the form of a resiliently flexible tube of fibre reinforced plastics material that has a naturally unstressed generally flat condition. Typically a suitable layflat type of hose has proved to be effective for the purpose. In this instance, the flexible tube

is orientated with the flat unstressed cross-sectional condition generally upright to provide openings on each side thereof for solids to settle towards the bottom of the gutter. Inflating the flexible tube hydraulically or pneumatically to its operative condition causes the outer surface of the tube to engage opposite upper regions of the gutter and form a passageway with the lower region of the gutter.

The invention also provides an assembly of individual containers interconnected with each other in modular relationship to provide an elongate in line series of containers and wherein each container has a horizontal collection surface as defined above with the channels collinearly aligned with corresponding channels in another individual container to form in line series of channels and with the tubular closures of in line channels conveniently forming part of a single length of flexible tube extending from one end of the series to the opposite end thereof and wherein the lower regions of the in series of line U-shaped gutters are interconnected to form a continuous passageway extending along the length of the series of in line containers.

In such an instance a fitting to which an end of the tubular closure is attached is located at one end of the in-line series of channels. The tubular closure may terminate short of the other end of the in-line series of channels to provide an inlet to a corresponding end of the in line passageways.

Further features of this aspect of the invention provide for the elongate tubular closure to pass through interconnecting sleeves communicating from one container to an adjacent container in which instance the interconnecting sleeves preferably have an internal diameter substantially the same as the transverse dimension across the upper region of the gutter; for the interconnecting sleeves to have at least one formation for restraining the collapsed elongate tubular closure to its generally upright orientation; and for the lower regions of the in line gutters of adjacent containers to be interconnected by means of aligned apertures in end walls of the individual

containers preferably having a diameter approximately the same as the transverse dimension of the lower region of the gutters.

Such a series of in line containers is particularly useful for conducting aquacultural activities such as, for example, the growing of abalone or other aquatic species.

In order that the above and other features of the invention may be more fully understood one embodiment thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:-

Figure 1 is a schematic cross-section taken through a container having a bottom formed to define a generally horizontal collection surface according to the invention;

Figure 2 is a schematic cross-section through a single channel of the collection surface illustrated in Figure 1 showing the elongate tubular closure in its collapsed, unstressed, inoperative condition;

Figure 3 is the same as Figure 2 but showing the elongate tubular closure in its expanded operative condition;

Figure 4 is a schematic sectional elevation of one terminal end of a channel or in line series of channels of a plurality of in line containers of a series of thereof;

Figure 5 is a similar schematic sectional elevation of the opposite terminal end of a channel or in line series of channels of a plurality of in line containers of a series of thereof;

Figure 6 is a plan view of the said opposite terminal end illustrated in

Figure 5;

Figure 7 illustrates schematically, in side elevation, three containers connected to each other in end to end relationship to form an in line series thereof;

Figure 8 is a schematic sectional elevation illustrating a junction between adjacent ends of two in line channels of two adjacent in line containers of a series such as that illustrated in Figure 7;

Figure 9 is a schematic cross section taken along line IX to IX in Figure 8.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

In the embodiment of the invention illustrated in the drawings, the apparatus for the removal of settled solids from bodies of liquids has its generally horizontal collection surface (1) forming the bottom of a container (2) that is particularly configured to be bolted to similar containers to form an in line series thereof, as illustrated in Figure 7.

The collection surface is composed of a plurality of parallel, juxtaposed, elongate channels (3) each of which is of basically Vee shape having downwardly convergent walls (4) that terminate in a deep, generally Li- shaped gutter (5) at the bottom of the channel. The angle of inclination of the convergent walls (4) is selected so that solids settling onto the surfaces slide

down the convergent wall surfaces and fall into the gutter that preferably has a depth that is about twice its width. The angle of inclination of the convergent walls is typically about 60 degrees to the horizontal, this being a generally accepted inclination for this purpose.

An elongate tubular closure (6) is associated with the upper region of the U- shaped gutter so as to extend along substantially the entire length of the gutter. The tubular closure is, in each case, a resiliently flexible tube of fibre or fabric reinforced plastics material (such as PVC) that has a naturally unstressed, generally flat condition. The flexible tube is orientated with the flat unstressed cross-sectional condition generally upright to provide openings (5a) on each side thereof for solids to settle past it into the gutter and onto the bottom of the gutter. This condition is clearly illustrated in Figure 2.

The tubular closure is inflatable to its normal approximately circular tubular configuration in which it is operative to cause the outer surface of the tube to engage opposite upper regions of the gutter to close the openings (5a) and form a passageway in a lower region of the gutter, as shown in Figure 3.

A suitable commercially available flexible tube that has been found to be effective for this purpose is that often referred to as a "layflat" fibre or fabric reinforced PVC hose that is particularly designed to be capable of being rolled up on a reel in a flat condition for use, for example, as a fire hose or an irrigation hose.

As indicated above, the container described generally forms one of an in line series of containers that are connected to each other with corresponding in line channels in linear alignment with each other. In such an instance only a single closure tube is conveniently employed for each in line series of channels and, in order to pass from one container to another, there are provided connecting sleeves (7) through which the tubular closure can pass.

In order to ensure optimum sealing, the inside diameter of these sleeves (7) is made to be the same as the distance between the walls of the upper region of the gutter against which the closure is to seal, in use, as will be clear from a reference particularly to Figure 9.

Similarly, the lower regions of the in line gutters are in communication with each other and form a continuous flow path beneath the connecting sleeves by way of aligned apertures (8) preferably having a diameter approximately the same as the transverse dimension of the lower region of the gutters in order to minimise obstruction to the flow of solids entrained in liquid during a solids removal cycle.

With the above arrangement it is only necessary for one end of each of the elongate closures to be attached to an inlet fitting (9) passing through an end wall of a terminal container in the in line series thereof, as shown in Figures 5 and 6. The inlet fitting is configured to hold the associated end (10) of the tubular closure in sealing association with the immediately adjacent part of the upper region of the U-shaped gutter.

The tubular closure in this embodiment of the invention terminates short of the outermost end wall (11) of the container so that its end (10) is spaced from the associated end wall (11). The inlet fitting includes is a relatively small diameter tube (12) that extends from the end (11) of the tubular closure and passes through the end wall of the container so as be capable of introducing and releasing compressed air into the elongate tubular closure. This arrangement provides a space (13) on each side of the small diameter tube between the end wall and end of the tubular closure, and thus an entrance to the passageway when the closure is expanded to its operative condition. This is shown clearly in Figure 6.

Accordingly, liquid contained in the terminal container is employed to enter the passageway and flush settled solids (14) out through the opposite end of

the passageway in consequence either of gravitational flow or suction applied to a coupling (15) at the opposite end of the passageway.

The opposite end (16) (see Figure 4) of the elongate tubular closure is closed off in any suitable manner such as by means of an end cap (17) on a sleeve (18) outside of the relevant end wall (19).

It will be understood that, in use, with the closure in its inoperative generally upright orientation, solids can pass it in order to settle onto the bottom of the gutter. As the solids accumulate, and generally at predetermined time intervals, the tubular closure is inflated by way of the fitting (9), typically using air under pressure, but also possibly water under pressure, so that it expands laterally to seal against the upper regions of the wall of the gutter and form the passageway described above and as illustrated in Figure 3.

Flow is then initiated out of the coupling (15) in order to create a flow of liquid entering the passageway by way of the spaces (13) from the remote terminal container. The flow may be consequent only on the head of water contained within the tank, that is to say simple gravitational flow through the passageway or, alternatively, as may be necessary or desired, suction could be applied to the coupling. In either event, in this manner accumulated solids are flushed from the entire length of the gutter. The cycle is repeated as and when required or according to a predetermined program.

It is to be noted that, depending on the construction of the tubular closure, it may be desirable to provide formations for holding the tubular closure in its generally flat upright orientation in order to ensure that the openings (5a) are substantially free. One arrangement that has proved to be successful is to provide a segment of tube (20) within a sleeve (7) so that its two cut edges (20a) are located in a vertical plane and serve as stops to the folded edges of the generally upright flattened tubular closure that is therefore unable to slew

around to a more horizontal position. This arrangement is illustrated in Figure 9.

It is envisaged that such a series of containers will be particularly useful for conducting aquacultural activities such as, for example, the growing of abalone or other aquatic species. In the instance of some species, the containers may have permeable baskets (21) supported therein, as shown in

Figure 1 , with fresh aerated (generally recycled) water entering by way of a distribution manifold (22) at the top; passing through the baskets; and gravitating laterally towards the centre from whence it is withdrawn by way of a return pipe (23) positioned above the bottom of the container.

It will be understood that numerous variations may be made to the embodiment of the invention described above without departing from the scope hereof. In particular, the containers may be individual containers unconnected with any others. Also the nature of the elongate tubular closure can vary widely provided that it is laterally expandable in order to effectively close off the upper region of the gutter. Also, numerous applications exist for the apparatus of this invention. Still further, the apparatus need not be embodied in the bottom of a container but it could be made in the form of an accessory for fitment into separate or existing containers.