GB1589848A - Device - Google Patents

Description

(54) DEVICE (71) We, FISONS LIMITED, a British Company, of Fison House, 9 Grosvenor Street, London WIX OAH, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to a device and its use.

In the raising of fish in land based vessels through which water is circulating, (hereinafter called fish farming), problems are encountered due to build up of noxious materials notably ammoniacal materials and oxidation products thereof. This is particularly the case where the water is recirculated several times through the vessel before being discharged to waste.

We have now devised a particularly suitable form of biological filter unit for use in the treatment of such water.

Accordingly, the present invention provides a fish farm comprising a series of vessels through which water is adapted to circulate and one or more units through which the water is adapted to pass, characterised in that at least one of the units is provided with a packing comprising a series of plate-like members mounted within the unit at an angle of not more than 40 to the intended line of flow of water through the unit.

Usually the unit will be operated with the plates wholly submerged and with water flowing up or down the unit. For convenience, the invention will be described herein in terms of a vertical flow of water. Where the flow is not vertical the overall line of flow will have to be identified and the angle of inclination of the plate-like members related to that flow and not to the vertical.

The plate-like members are angled at not more than 40 and preferably at more than 5 to the vertical to reduce the risk of blockage due to build up of bios. The inclination also aids spread of water over the members when the unit is used as a trickle filter. It is preferred to incline the plate-like member at 10 to 35 , e.g. 15 to 30 , to the vertical. The terms plate-like member and plate are used herein to denote a generally flat member whose surface need not be a single plane. That is, the member may be a flat sheet of material or may be a sheet having a corrugated or irregular surface. The plane with reference to which the angle of inclination is assessed is the median plane of the member as a whole.

However, it is preferred that only a minor proportion (i.e. less than 50%) of the total area of the exposed surface of the member be inclined at one than 40 to the vertical.

The angles of inclination quoted herein are measured between the vertical and the plane of the plate-like member, that is an angle of inclination of 0 corresponds to a plate having its plane vertical.

The unit conveniently takes the form of a vessel e.g. a tank or an upright tower, having a squared, rounded or other shaped crosssection. The vessel is, for example, made of brick, sheet plastic or other material, e.g.

stainless steel. The packing is preferably in the form of sheets, e.g. of plastic or stainless steel, suspended or mounted at the requisite angle in the vessel. The unit can be operated as a conventional trickle filter, with the water being treated flowing as a film over the packing.

Alternatively, the unit is operated as a submerged bed in which the plates are wholly or partially immersed in the water whichiflows longitudinally and/or transversely -across, up or down the vessel. Desirably, the plates are mounted in stacks with 2-10 cm spacing between the plates. The plates may be flexible sheets of material suspended from a suitable frame work or may be slelf-supporting or rigid.

In a particularly preferred embodiment, the plates are perforated whereby water may flow over and through the plates and bacterial growth may occur on all exposed surfaces of the plate. We have found that a perforated plate is surprisingly more effective than an imperforate plate. The perforations in the plate may be of any suitable size, e.g. 1 to 20 mm greatest dimension or diameter, and of any suitable shape, e.g. round holes, slitted apertures, polygonal holes etc.

The plates may be supported or mounted in the unit by any suitable means and the unit may be provided with means for injecting air or oxygen to aid the bacterial action. The use of the inclined plate packing for the unit offers the advantages over alternative forms of packing that the need for back washing of the unit to remove blockages and excess bios is reduced and that, by virtue of the inclined plates, the unit may serve as a solids separator as well as a biological treatment device.

Apart from the type of packing to be used in the biological filter unit, the fish farm and its operation are of conventional form. The invention therefore provides a method for raising fish in a land based vessel through which water is circulating characterised in that at least part of the water is also passed through a unit in which the water is biologi cally treated, which unit is provided with a series of plate-like members inclined at not more than 40 to the overall line of flow of water through the unit. Preferably, the water flows'substantially vertically through the unit and the plate-like members are substantially wholly immersed in the water.

The water can be treated in a unit located adjacent each vessel (so that each vessel and unit forms a self-contained unit) or can be treated at a unit serving a plurality of vessels.

If desired, each unit can be provided with -means for separating solids from the water, e.g. a settling tank, a mesh filter or a gravel bed filter, to remove suspended solids from the water before it enters the unit and/or to remove bios which is shed from the packing from water leaving the unit. If desired, means for controlling the pH of the water may be provided, e.g. as limestone or shell chips placed on top of the packing of a sand or gravel bed filter. A particularly preferred form of fish farm employs the land based vessels and method described and claimed in our co-pending application No. 8814/76.

(Serial No. 1567171).

The use of the above form of unit provides a particularly compact and effective means for reconditioning the water circulating through a fish farm.

Whilst the invention has been described above in terms of land based vessels, it can -be applied to other forms of enclosure, e.g.

ponds, in which fish are reared. The term vessel is used herein collectively to denote also these other forms of enclosure.

WHAT WE CLAIM IS: 1. A fish farm comprising a series of vessels through which water is adapted to circulate and one or more units through which the water is adapted to pass, characterised in that at least one of the units is provided with a packing comprising a series of plate-like members mounted within the unit at an angle of not more than 40 to the intended line of flow of water through the unit.

2. A method for raising fish in a land based vessel through which water is circulating characterised in that at least part of the water is also passed through a unit in which the water is biologically treated, which unit is provided with a series of plate-like members inclined at not more than 40 to the overall line of flow of water through the unit.

3. A fish farm or method as claimed in either of claims 1 or 2, wherein the flow of water is substantially vertical through the unit.

4. A fish farm or method as claimed in any one of claims 1 to 3, wherein the platelike members are inclined at from 5 to 35 to the line or intended line of flow of water through the unit.

5. A fish farm or method as claimed in any of the preceding claims, wherein the plate like members are mounted generally parallel to one another.

6. A fish farm or method as claimed in claim 5, wherein the plate-like members are spaced from 2 to 10 cms from one another.

7. A fish farm or method as claimed in any one of the preceding claims wherein the plate-like members are perforated.

8. A fish farm or method as claimed in any of the preceding claims, wherein means are provided for injecting oxygen into the unit.

9. A fish farm or method as claimed in any one of the preceding claims, wherein each vessel is provided with a unit having a packing comprising a series of plate-like members inclined at an angle of not more than 40 to the intended line of flow of water through the unit.

10. A fish farm or method as claimed in any one of the preceding claims, wherein means are provided for separating solids from water before and/or after it passes through the unit.

11. A fish farm or method as claimed in any one of the preceding claims, wherein the series of vessels comprises at least one vessel substantially as described and claimed in our co-pending Application No. 8814/76. (Serial No. 1567171).

12. A fish farm or method as claimed in either of claims 1 or 2 substantially as hereinbefore described.

13. A method as claimed in any one of the preceding claims wherein the p]ate-like members are substantially wholly immersed in the water passing through the unit.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (13)

**WARNING** start of CLMS field may overlap end of DESC **. of any suitable shape, e.g. round holes, slitted apertures, polygonal holes etc. The plates may be supported or mounted in the unit by any suitable means and the unit may be provided with means for injecting air or oxygen to aid the bacterial action. The use of the inclined plate packing for the unit offers the advantages over alternative forms of packing that the need for back washing of the unit to remove blockages and excess bios is reduced and that, by virtue of the inclined plates, the unit may serve as a solids separator as well as a biological treatment device. Apart from the type of packing to be used in the biological filter unit, the fish farm and its operation are of conventional form. The invention therefore provides a method for raising fish in a land based vessel through which water is circulating characterised in that at least part of the water is also passed through a unit in which the water is biologi cally treated, which unit is provided with a series of plate-like members inclined at not more than 40 to the overall line of flow of water through the unit. Preferably, the water flows'substantially vertically through the unit and the plate-like members are substantially wholly immersed in the water. The water can be treated in a unit located adjacent each vessel (so that each vessel and unit forms a self-contained unit) or can be treated at a unit serving a plurality of vessels. If desired, each unit can be provided with -means for separating solids from the water, e.g. a settling tank, a mesh filter or a gravel bed filter, to remove suspended solids from the water before it enters the unit and/or to remove bios which is shed from the packing from water leaving the unit. If desired, means for controlling the pH of the water may be provided, e.g. as limestone or shell chips placed on top of the packing of a sand or gravel bed filter. A particularly preferred form of fish farm employs the land based vessels and method described and claimed in our co-pending application No. 8814/76. (Serial No. 1567171). The use of the above form of unit provides a particularly compact and effective means for reconditioning the water circulating through a fish farm. Whilst the invention has been described above in terms of land based vessels, it can -be applied to other forms of enclosure, e.g. ponds, in which fish are reared. The term vessel is used herein collectively to denote also these other forms of enclosure. WHAT WE CLAIM IS:

1. A fish farm comprising a series of vessels through which water is adapted to circulate and one or more units through which the water is adapted to pass, characterised in that at least one of the units is provided with a packing comprising a series of plate-like members mounted within the unit at an angle of not more than 40 to the intended line of flow of water through the unit.

2. A method for raising fish in a land based vessel through which water is circulating characterised in that at least part of the water is also passed through a unit in which the water is biologically treated, which unit is provided with a series of plate-like members inclined at not more than 40 to the overall line of flow of water through the unit.

3. A fish farm or method as claimed in either of claims 1 or 2, wherein the flow of water is substantially vertical through the unit.

4. A fish farm or method as claimed in any one of claims 1 to 3, wherein the platelike members are inclined at from 5 to 35 to the line or intended line of flow of water through the unit.

5. A fish farm or method as claimed in any of the preceding claims, wherein the plate like members are mounted generally parallel to one another.

6. A fish farm or method as claimed in claim 5, wherein the plate-like members are spaced from 2 to 10 cms from one another.

7. A fish farm or method as claimed in any one of the preceding claims wherein the plate-like members are perforated.

8. A fish farm or method as claimed in any of the preceding claims, wherein means are provided for injecting oxygen into the unit.

9. A fish farm or method as claimed in any one of the preceding claims, wherein each vessel is provided with a unit having a packing comprising a series of plate-like members inclined at an angle of not more than 40 to the intended line of flow of water through the unit.

10. A fish farm or method as claimed in any one of the preceding claims, wherein means are provided for separating solids from water before and/or after it passes through the unit.

11. A fish farm or method as claimed in any one of the preceding claims, wherein the series of vessels comprises at least one vessel substantially as described and claimed in our co-pending Application No. 8814/76. (Serial No. 1567171).

12. A fish farm or method as claimed in either of claims 1 or 2 substantially as hereinbefore described.

13. A method as claimed in any one of the preceding claims wherein the p]ate-like members are substantially wholly immersed in the water passing through the unit.