WO1997002740A2

WO1997002740A2 - Delivery system

Info

Publication number: WO1997002740A2
Application number: PCT/GB1996/001654
Authority: WO
Inventors: Marion Welsh; Alex Howie
Original assignee: Mauchline Business Services
Priority date: 1995-07-11
Filing date: 1996-07-11
Publication date: 1997-01-30
Also published as: WO1997002740A3; AU6463596A

Abstract

In a fluid delivery system, particularly for distributing water borne food to offshore fish cages (31, 32, 33, 34, 35 and 36), in which each cage is individually addressable using a fluid address bus (61, 62, 63, 64) and fluid address decoders (51, 52, 53, 54, 55 and 56) to activate diverters (41, 42, 43, 44, 45 and 46) from a common fluid supply line (10) to each individual cage.

Description

Delivery Svstem

This invention relates to a delivery system and particularly, though not exclusively, a delivery system for delivering particles suspended in a fluid to a number of discrete locations. One particular application to which the invention is suited is the delivery of water borne food particles to a number of discrete fish tanks at a fish farm.

A fish farm will commonly have a number of discrete fish tanks in the form of large cages which are moored offshore in the sea or in freshwater and which contain the fish being farmed. Floating walkway are usually placed between and connect the discrete tanks. In order to feed the fish, the fish farmer visits each tank in turn to sprinkle fish food over each tank usually by walking on the floating walkway which may extend to the shore. This is both time consuming and inconvenient.

According to a first aspect, the present invention provides a system for distributing a fluid from a common fluid*supply line to a plurality of delivery locations in which each delivery location has associated therewith a respective valve which is operable to selectively allow or restrict fluid communication between the fluid supply line and the delivery location, a respective valve actuator for actuating the valve in response to a respective control actuating signal and in which each valve actuator is connected to at least one common control line such that the presence of its respective control signal on the control line causes the respective valve actuator to actuate the respective valve.

The system may be used for distributing fluid to any one of the delivery locations from a common fluid supply line by issuing the appropriate control signal on the control line.

Each discrete delivery location may be connected to the fluid supply line by a respective fluid branch line. The valve may be positioned part way along the fluid branch line between the delivery location and the connection between the branch line and the fluid supply line.

Preferably, the control line is provided by a plurality of address lines and each valve actuator is provided as an address decoder connected to each of the address lines. The address lines may together form an address bus. The fluid may be distributed to a selected delivery location by issuing an appropriate address on the address bus to actuate the desired valve. The address bus may operate in binary format, each address line being switchable between one of two states.

The fluid may carry a solid or one or more particles, flakes or pellets to be delivered to one of the delivery locations.

According to a second aspect, the present invention provides a method of selectively distributing a solid suspended in a fluid from a fluid supply line to one of a plurality of delivery locations comprising the steps of: a) providing at least one of the delivery locations with a respective valve which is operable to selectively permit or restrict fluid communication between the fluid supply line and that delivery location; b) providing a valve actuator for alternatively permitting or preventing operation of the valve; c) providing a control line connected to the valve actuator; and d) issuing a control signal on the control line to cause the valve actuator to operate or permit operation of the valve.

Preferably, a plurality of delivery locations lines are provided, each with a respective valve and valve actuator by means of which it is connected to a common supply line. A plurality of control lines may be provided and in this case each valve actuator is preferably connected to each of the control lines. The control lines may be provided by address lines forming an address bus and the valve actuator may be provided by an address decoder.

The delivery location or locations may be connected to the fluid supply line by means of a respective fluid branch line.

The or each valve may be operable by a power line, preferably a common power line. The or each address decoder may be arranged to alternatively connect or disconnect the power line to the valve to operate the valve in response to that address decoder being alternatively addressed or not addressed on the address bus (ie on an enabling or disenabling control signal being issued for that address decoder on the control line) .

The system or the method may be used to distribute fluid borne food to a plurality of offshore fish tank, each fish tank being a discrete delivery location and with a respective fluid branch line feeding each respective tank from a common fluid supply line. A portion of the fluid supply line may be provided on land so that the food can be distributed from land to the fish tanks offshore. Respective portions of the control line or control lines and the power line may similarly be provided on shore; this allows on shore selection of the tanks to which the food is to be directed.

The fluid of the fluid supply line is preferably water. This may conveniently be seawater where the fish tanks are in the sea or freshwater where the tanks are in freshwater.

The control line or control lines are preferably fluid control lines. They may be hydraulic or pneumatic. The or each control line may be used to provide a binary signal, a first pressure of fluid in the control line representing a binary zero and a second pressure representing a binary one. In this way, the control lines can be used to provide an address bus providing a digital address.

Where the control lines are partially offshore, the fluid is advantageously seawater or freshwater.

The use of fluid control lines avoids the necessity of having electrical control lines. This may be intrinsically safer and avoid the necessity of isolation of electrical cables and connectors and the risk of possible corrosion.

Similarly, the power line may be a fluid power line and the fluid may be seawater or freshwater.

According to a third aspect, the present invention provides a fluid actuated address decoder comprising at least a first and a second address module each of which comprises: a) a passageway between a fluid inlet and a fluid outlet; b) a fluid address input; and c) means responsive to pressurisation of the fluid address input for selectively permitting and restricting fluid communication through the passageway between the fluid input and the fluid output; and in which the fluid input of the second module is connected to the fluid output of the first module.

The address decoder may have any number of modules, for example, three, four, five, six or more with the fluid output of each module being connected to the fluid input of the next module. The modules are preferably connected in series.

The means responsive to pressurisation of the fluid address input at any module may alternatively either: a) allow communication between the fluid input and fluid output of that module when the fluid address input is at a relatively high pressure (ie a logic one open valve module) and restrict communication in response to relatively low pressurisation of the fluid address input; or b) allow communication between the fluid input and the fluid output of that module when the fluid address input is at a relatively low pressure (ie a logic zero open valve module) and restrict communication in response to a relatively high pressure at the fluid address input.

The means may be provided by a piston or a valve which may have a spring return.

One or more of the address decoders may be switchable between being a logic one open valve module and being a logic zero open valve module.

One or more modules may have a first fluid passageway between a first fluid inlet and a first fluid outlet, a second fluid passageway between a second fluid inlet and second fluid outlet, a fluid address input, first means responsive to pressurisation at the fluid address input for selectively either: a) allowing fluid communication between the first fluid input and the first fluid output whilst restricting fluid communication between the second fluid input and the second fluid output; or b) allowing fluid communication between the second fluid input and the second fluid output whilst restricting fluid communication between the first fluid input and the first fluid output; and second means for selectively restricting fluid communication either through the first passageway or through the second passageway.

The second means may be provided by a manually movable plug or switch which may be positioned to block either the first or the second passageway.

According to a fourth aspect, the present invention provides an address module for an address decoder in accordance with the third aspect of the invention.

According to a fifth aspect, the present invention provides a rotatable distributor for distributing fluid borne particles over an area, the distributor comprising means for causing rotation of the distributor and at least one deflector which rotates with the distributor for deflecting particles which impinge upon it.

Preferably, a plurality of deflectors are provided. The deflector of deflectors may be provided in the form of deflector blades which may depend from a deflector surface.

The means for causing rotation of the distributor may comprise one or more rotating blades, which may be provided as turbine blades.

A single blade may act both as a deflector blade and a rotating blade.

The distributor may be substantially conical in shape. The sides of the cone may be curved and may provide the deflector surface. The deflector or deflectors may be provided on a side of the cone such as to be rotatable about an axis passing through an apex the cone. A fluid supply line may be arranged to direct a fluid carrying particles to be distributed toward the apex of the cone and over the deflector surface such that when the distributor rotates, the rotating deflector blade or blades impinge on the particles causing them to be deflected and distributed away from the distributor.

The or each rotating blade may depend from a surface of the cone opposite the apex. A fluid may be arranged to impinge upon the rotating blade or blades to rotate the distributor.

The distributor may be used to distribute fluid borne fish food over the area of a fish tank. It may be used in association with the delivery system and method described above. In this case, an output from the fluid power line may be arranged to selectively cause rotation of the distributor at the fish cage where the distributor is located upon the address of that fish cage being selected on the address bus.

The distributor may be arranged to float on or partially in water; it may have a flotation collar for this purpose. It is preferably arranged to float at or towards the centre of a fish cage.

According to a sixth aspect, the present invention provides a diverter having an inlet port, an outlet port and a hollow spool movable transversely in relation to direction of fluid flow through the diverter between a first position in which fluid supplied at the inlet port is directed through the spool and through the diverter to the outlet port and a second position in which fluid communication from the inlet port to the outlet port is restricted.

The diverter may be used as part of a delivery system as described herein.

The diverter preferably has a second outlet port and the spool is preferably movable transversely in relation to the direction of fluid flow between a first position, in which fluid supplied at the inlet port is directed through the diverter to the first outlet port, and a second position, at which fluid supplied at the inlet port is directed through the diverter to the second outlet port. Further outlet ports may be provided with further associated positions of the spool.

The inlet and outlet ports may be co-planar.

The diverter may comprise a body to which the inlet and outlet port(s) are connected. The spool may move within the body. The inlet and outlet port(s) are preferably spaced around the perimeter of the body. The spool and an interior portion of the body may cooperate to guide and/or facilitate sliding of the spool within the body. For example, a portion of the interior of the body and the spool may be substantially cylindrical; in this case, a guide peg and slot or some other guide formation may be provided to prevent rotation of the spool within the body. Alternatively, portions of the interior of the body and the spool may have one or more cooperating, flat surfaces.

The spool may be provided as an elongate member; it may have two, sealed, opposing ends with a perimeter wall extending therebetween. The perimeter wall may have an inlet orifice and a spaced outlet orifice. The outlet orifice is preferably spaced radially from the inlet orifice around the perimeter of the perimeter wall and may be spaced axially from the inlet orifice. When the diverter is to be used with first and second outlet ports, a second outlet orifice may be provided in the perimeter wall, spaced radially and axially from the first outlet port. Further outlet orifices may be provided in a similar way for further outlet ports.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Fig. 1 is a schematic overview of a fish farm feed delivery system in accordance with the invention; Fig. 2 is a sectional view through a module of an address decoder in a first configuration; Fig. 3 is a plan view of a selector associated with the address decoder module; Fig. 4 is a sectional view through the address decoder module in a second configuration; Fig. 5 is a sectional view through an address decoder constructed from a number of address decoder modules; Fig. 6 is a perspective view of a distributor; Fig. 7 is a top plan view of the distributor of Fig. 6; Fig. 8 is a plan view of the diverter for use in the delivery system; Fig. 9 is a cross-sectional side view of the diverter of Fig. 8; and Fig. 10 is a perspective view of a spool of the diverter.

Fig. 1 shows a system for distributing a fluid from a fluid supply line 10 to a plurality of fluid branch lines 21, 22, 23, 24, 25, 26. Each fluid branch line feeds a respective cage 31, 32, 33, 34, 35, 36, of an off-shore fish farm.

The fluid supply line 10 is used to distribute particles of fish food suspended in water selectively through each of the fluid branch lines and hence to the respective fish tanks. The fish food is introduced into the fluid supply line 10 by means of a feed batching hopper 11 and a feed ejector 12. The fluid is preferably sea water or fresh water taken from the water supply in which the fish tanks are located.

Each fluid branch line has a respective valve in the form of a diverter 41, 42, 43, 44, 45, 46 associated therewith for selectively connecting or disconnecting the respective delivery location to the fluid supply line 10 through the fluid branch line. Each diverter is actuated by a respective valve actuator in the form of an address decoder 51, 52, 53, 54, 55, 56.

The system is controlled by a control signal issued on a control line in the form of an address bus comprising, in this example, four individual address lines 61, 62, 63, 64. Each address line is provided as a fluid line which is pressurised at a first pressure to represent a logic 1 and pressurised at a second lower pressure to represent a logic 0. The logic 0 may be provided when no external pressure is applied to the address line.

The system also has a common fluid power line 14 to which each of the addressed decoders is permanently connected.

Hydraulic power for the system is provided by a pump feed strainer and foot valve 15, a transport medium pump 16 and a hydraulic address control pump 17.

In a typical application, each of the address lines 61, 62, 63, 64 may run at about 30 psi when pressurised to provide a logic one signal and the fluid power line 14 may be pressurised to about 60 psi.

Each tank in the fish farm has a unique digital address set by the configuration of its respective address decoder. Each address decoder is permanently connected to each address line on the address bus. Selection of a particular address on the address bus causes the appropriate address decoder to allow passage of fluid from the fluid power line to its respective diverter to provide fluid communication between the fluid supply line 10 and the respective tank through the respective fluid branch line.

The diverter may be provided with a semi rotary paddle which is operable to selectively allow or obstruct flow of fluid through the diverter from the fluid power line 14 to the respective tank.

The paddle may be openable to provide communication upon connection of pressurized fluid from the fluid power line 14 to the respective diverter. The paddle may be provided with a spring return and a metered pressure release orifice. Upon interruption of the connection between the fluid power line 14 and the respective distributor when the respective address is de-selected from the address bus, the remaining pressure acting to keep the diverter open may leak out through the metered relief orifice to enable the diverter to close.

A particularly preferred form of diverter is described further on.

Each of the address lines has a metered bleed to sea as indicated at 18 to allow the pressure in each address line to reduce to sea or atmospheric pressure when its respective power supply causing the pressurisation is disconnected.

Fig. 2 shows a module 101 which forms part of an address decoder. The module 101 has a first passageway 111 between a first input 112 and a first output 113 and a second passageway 121 between a second input 122 and a second output 123. The module has a valve in the form of a spring returned piston 102 which is operable in response to pressurisation of an address input 103 to selectively either (a) allow passage of fluid through the first passageway 111 whilst preventing passage of fluid through the second passageway 121 or (b) prevent passage of fluid through the first passageway 111 whilst allowing passage of fluid through the second passageway 121. A moveable plug 104 may be positioned to block either the first passageway 111 or the second passageway 121.

Each of the inputs 112, 122 is connected to the fluid power line 14; the address input 103 is connected to one of the address lines. In the configuration shown in Fig. 2, pressurisation of the address input 103 forces the piston 102 against a spring 105 to allow fluid communication through the first passageway 111 from the first input 112 to the first output 113 whilst blocking the flow through the second passageway 121. Release of pressure from the address input 103, as shown in Fig. 4, causes the spring 105 to move the piston 102 to prevent passage of fluid through the first passageway 111 whilst allowing the flow of fluid through the second passageway 121. In the configuration shown, the second passageway 121 is blocked by a plug 104. Consequently, with both inputs 112 and 122 connected to the fluid power line 14, pressurisation of the address input 103 causes fluid communication across the module (in this case to the first output 113) to provide a fluid flow 106 whilst release of pressure at the address input 103 blocks communication through the module thus discontinuing fluid flow through the module.

In this configuration, the module 101 allows fluid communication when the address input 103 is pressurized ie it works as a logic one open valve. When the plug 104 is moved by a manual rotatable actuator so that it blocks the first passageway 111 and no longer blocks the second passageway 121 then the module will allow fluid communication across it when the address input 103 is not pressurized and prevent fluid communication when the address input 103 is pressurized. In this configuration, the module acts as a logic zero open valve.

Fig. 5 shows an address decoder comprising three connected modules 201, 301, 401. The inputs 212, 222 of the first module 201 are connected to each of the outputs 313, 323 of the second module 301; the inputs 312, 322 of the second module 301 are connected to each of the outputs 413, 423 of the third module 401. In the configuration shown, the address decoder only permits fluid communication between the fluid power line 14 (which is connected to the inputs 412, 422 of the third module 401) and an address decoder output 107 (provided by the outputs 213, 223 of the first module 201) when: (a) the input address 203 of the first module is not pressurized (ie logic 0) ; and (b) the input address 303 of the second module 301 is not pressurized (ie logic 0) ; and (c) the address input 403 of the third module 401 is pressurized (ie logic l) . Any other combination at the address inputs 203, 303, 403 disconnects the fluid power line 14 from the address decoder output 107.

The address of the address decoder (ie the combination of signals at the address inputs which enable the address decoder) can be changed by altering the configurations of the plugs 204, 304, 404.

Fig. 6 and Fig. 7 show a rotatable distributor 601 which is provided in a substantially cone shaped configuration.

A separate distributor 601 is provided at each individual fish tank; the respective fluid branch line delivers fluid carrying solid feed pellets to a position above an apex 603 of the distributor.

A plurality of rotating blades 607 provided in the form of turbine blades are mounted radially around the periphery of and protrude downwardly from a deflector blade surface 608 provided by the underside of the distributor 601. In order to rotate the distributor, a number of fluid jets are mounted under the distributor towards its centre and are set to direct a flow of fluid outwards to impinge on the blades 607. The fluid jets are supplied with pressurised fluid from the fluid power line 14 when the appropriate address is issued on the address bus to allow passage of fluid from the fluid power line through the appropriate address decoder. The distributor is thus provided with means to cause its rotation in the form of a hybrid impulse/pelton fluid turbine.

The distributor 601 is arranged on a mounting tray (not shown) which is supported by a flotation collar (not shown) arranged around it. The exhaust from the turbine drains through holes in the base of the mounting tray.

Curved-aides 6Q9 of the cone shaped distributor 601 provide a deflector surface on which four deflector blades 610 are mounted. The deflector blades 610 run from a position towards the apex 603 of the cone towards a lower edge 611 of the side 609 of the cone. When the distributor is rotated, the deflector blades 610 impart rotational energy from the distributor 601 to any material on which they impinge such that the material, when it reaches the edge of the distributor, has gained sufficient energy to leave the distributor in a tangential manner and thus be distributor across an area. The area may be, for example, the surface area of the fish cage. Not all of the material will acquire the same energy as not all of the material will remain in contact with the distributor surface for the full length of the blade. The spread of material from the distributor will thus be fairly evenly distributed in a radial pattern.

Fig. 8, Fig. 9 and Fig. 10 show a preferred form of diverter 80 having an inlet port 83, a first outlet port 81 and a second outlet port 82. Each of the ports is connectable to pipes to incorporate the diverter into the delivery system. The ports are co-planar and are spaced around the perimeter of a diverter body 84.

A hollow spool 85 is housed within the diverter body 84. The spool has a perimeter wall 86 and closed ends 87, 88. O-ring seals 89 are housed in respective perimeter grooves 90 towards each end of the spool 85 to seal the spool within the diverter body 84. The spool has an inlet orifice, a first outlet orifice 91 and a second outlet orifice 92 spaced radially and axially from the first outlet orifice 91.

The spool is slidable within the diverter body 84 from a first position (shown in Fig. 9) to a second position. In the first position, fluid can pass through the spool from the inlet port 83, through the inlet orifice, through the first outlet orifice 91 to the first outlet port 81; the second outlet port 82 is blocked by the perimeter wall 86 of the spool 85. In the second position (in which position the spool 85 is moved upwardly compared with the position shown in Fig. 9) fluid can pass through the spool 85 from the inlet port 83, through the inlet orifice, through the second outlet orifice 92 to the second outlet port 82; in this position, the first outlet port 81 is blocked by the perimeter wall 86 of the spool 85.

A slide mechanism (not shown) is provided to permit the desired sliding movement of the spool 85 within the diverter body 80 and to prevent substantial rotation of the spool within the body.

The diverter body 80 may have open ends; a limit means is preferably provided to limit the extent of permitted movement of the spool 85 within the body 80. The spool 85 may be resiliently mounted such that it is biased to one of its positions. In this case, a single actuator may be used to displace and hold the spool against the spring bias when desired. Preferably, however, an actuator is associated with each end of the spool 85 to move the spool positively in each direction between its possible positions. This may be desirable when fluid borne food particles, for example fish pellets, are passed through the diverter as pellets may become lodged between the spool 85 and the body 80. Provided the spool 85 can be displaced with sufficient force to overcome any resistance, for example, by crushing or displacing any trapped particles, then this should not adversely affect functioning of the diverter. It will be appreciated that in some applications the integrity of the seal between the spool 85 and the body 80 is not critical. For example, a small amount of fluid leakage would not adversely affect functioning of the device when used to deliver fluid borne food particles to offshore fish tanks.

In the system described, the fluid lines may be provided by plastic hose pipes. Where the cages are offshore, the lines may run below the surface of the water; they may be suspended on a floating walkway which extends to and/or between the cages. Connectors connecting the pipes or hoses may be positioned above the surface of the water.

The required number of address lines depends upon the number of individual locations that are to be addressed. The address system is binary in nature and hence, two address lines will in theory allow 4 stations to be selected, 3 address lines allow 9 stations to be selected, 4 address lines allow 16 stations to be selected as so on. In practise, it may be decided to have the number of selectable stations as two less than the theoretical maximum since the address 0 (with none of the address lines pressurised) , may be reverted to simply when the system is idle and an address where all of the address lines are pressurised simultaneously may be used flush the address bus.

The pumps that power the system may be permanently installed and may be provided by electric motors. Alternatively, the system may be portable or partially portable and in this case may have pumps powered by a generator driven electric motor or motors or by some other prime mover, for example, a diesel or petrol engine. The pumps and any electronic controls associated with the system may be containerised to allow for easy transportation; they may be trailer mounted. The fluid supply line, fluid power line, address lines,address decoders and diverters may form part of a permanent installation at a site which are connectable to a transportable power supply unit to operate the system.

Claims

1. A system for distributing a fluid from a common fluid supply line to a plurality of delivery locations in which each delivery location has associated therewith a respective valve which is operable to selectively allow or restrict fluid communication between the fluid supply line and the delivery location, a respective valve actuator for actuating the valve in response to a respective control actuating signal and in which each valve actuator of the system is connected to at least one common control line such that the presence of its respective control signal on the control line causes the respective valve actuator to actuate the respective valve.

2. A system in accordance with Claim 1, in which each discrete delivery location is connected to the common fluid supply line by a respective fluid branch line.

3. A system in accordance with Claim 2, in which the valve of at least one delivery location is positioned part way along the fluid branch line between the delivery location and the connection between the branch line and the fluid supply line.

4. A system in accordance with any preceding claim, in which the control line is provided by a plurality of address lines and each valve actuator of the system is provided as an address decoder connected to each of the address lines.

5. A system in accordance with Claim 4, in which the address lines form an address bus.

6. A system in accordance with Claim 5, in which the address bus operates in binary format, each address line being switchable between one of two states.

7. A system in accordance with any preceding claim, in which the fluid is adapted to carry a solid or one or more particles, flakes or pellets to be delivered to one of the delivery locations.

8. A method of selectively distributing a solid suspended in a fluid from a fluid supply line to one of a plurality of delivery locations comprising the steps of: a) providing at least one of the delivery locations with a respective valve which is operable to selectively permit or restrict fluid communication between the fluid supply line and that delivery location; b) providing a valve actuator for alternatively permitting or preventing operation of the valve; c) providing a control line connected to the valve actuator; and d) issuing a control signal on the control line to cause the valve actuator to operate or permit operation of the valve.

9. A method in accordance with Claim 8, in which a plurality of delivery location lines are provided, each with a respective valve and valve actuator by means of which it is connected to a common supply line.

10. A method in accordance with Claim 8 or Claim 9, in which a plurality of control lines are provided and in which each valve actuator is connected to each of the control lines.

ll. A method in accordance with any one of Claims 8 to 10, in which control lines are provided by address lines forming an address bus and the valve actuator is provided by an address decoder.

12. A method in accordance with any one of Claims 8 to 11, in which the delivery location or locations are connected to the fluid supply line by means of a respective fluid branch line.

13. A method in accordance with any one of Claims 8 to 12, in which the valve is operable by a common power line.

14. A method in accordance with any one of Claims 8 to 13 used to distribute fluid borne food to a plurality of offshore fish tank, each fish tank being a discrete delivery location and with a respective fluid branch line feeding each respective tank from a common fluid supply line.

15. A method in accordance with Claim 14, in which portion of the fluid supply line is provided on land so that the food can be distributed from land to the fish tanks offshore.

16. A method in accordance with Claim 14 or Claim 15, in which portions of the control lines and the power line are provided on shore to allow on shore selection of the tanks to which the food is to be directed.

17. A method in accordance with any one of Claims 14 to 16, in which the fluid of the fluid supply line is water.

18. A method in accordance with any one of Claims 8 to 17, in which the control line or control lines are fluid control lines.

19. A method in accordance with any one of Claims 8 to 18, in which the control lines are used to provide an address bus providing a digital address.

20. A method in accordance with any one of Claims 8 to 19, in which the fluid used in the control lines is seawater or freshwater.

21. A fluid actuated address decoder comprising at least a first and a second address module each of which comprises: a) a passageway between a fluid inlet and a fluid outlet; b) a fluid address input; and c) means responsive to pressurisation of the fluid address input for selectively permitting and restricting fluid communication through the passageway between the fluid input and the fluid output; and in which the fluid input of the second module is connected to the fluid output of the first module.

22. An address decoder in accordance with Claims 21, in which the means responsive to pressurisation of the fluid address input is provided by a spring return piston.

23. An address decoder in accordance with any Claims 21 or 22, in which at least one address decoder is switchable between being a logic one open valve module and being a logic zero open valve module.

24. An address decoder in accordance with any one of Claims 21 to 23, in which at least one module has a first fluid passageway between a first fluid inlet and a first fluid outlet, a second fluid passageway between a second fluid inlet and second fluid outlet, a fluid address input, first means responsive to pressurisation at the fluid address input for selectively either: a) allowing fluid communication between the first fluid input and the first fluid output whilst restricting fluid communication between the second fluid input and the second fluid output; or b) allowing fluid communication between the second fluid input and the second fluid output whilst restricting fluid communication between the first fluid input and the first fluid output; and second means for selectively restricting fluid communication either through the first passageway or through the second passageway.

25. An address decoder in accordance with Claim 24, in which the second means is provided by a manually movable plug or switch which may be positioned to block either the first or the second passageway.

26. An address module for an address decoder in accordance with any one of Claims 21 to 25.

27. A rotatable distributor for distributing fluid borne particles over an area, the distributor comprising means for causing rotation of the distributor and at least one deflector which rotates with the distributor for deflecting particles which impinge upon it.

28. A distributor in accordance with Claim 27, in which the deflector of deflectors are provided in the form of deflector blades which depend from a deflector surface.

29. A distributor in accordance with Claims 27 or 28, in which the means for causing rotation of the distributor comprises one or more rotating turbine blades.

30. A distributor in accordance with any one of Claims 27 to 29 in which a single blade acts both as a deflector blade and a rotating blade.

31. A distributor in accordance with any one of Claims 27 to 30, in which the distributor is substantially conical in shape.

32. A distributor in accordance with Claim 31, in which sides of the cone are curved and provide the deflector surface.

33. A distributor in accordance with Claims 31 or 32, in which the deflector or deflectors are provided on a side of the cone such as to be rotatable about an axis passing through an apex the cone.

34. A system in accordance with any one of Claims 1 to 7 incorporating a distributor in accordance with any one of Claims 31 to 33, in which a fluid supply line is arranged to direct a fluid carrying particles to be distributed toward the apex of the cone and over the deflector surface such that when the distributor rotates, the rotating deflector blade or blades impinge on the particles causing them to be deflected and distributed away from the distributor.

35. A system in accordance with Claim 34, in which the or each rotating blade depends from a surface of the cone opposite the apex.

36. A system in accordance with Claim 35, in which fluid is arranged to impinge upon the rotating blade or blades to rotate the distributor.

37. A system in accordance with any one of Claims 34 to 26, in which the distributor is arranged to float on or partially in water.

38. A diverter having an inlet port, an outlet port and a hollow spool movable transversely in relation to direction of fluid flow through the diverter between a first position in which fluid supplied at the inlet port is directed through the spool and through the diverter to the outlet port and a second position in which fluid communication from the inlet port to the outlet port is restricted.

39. A diverter in accordance with Claim 38, in which the diverter has a second outlet port and the spool is movable transversely in relation to the direction of fluid flow between a first position, in which fluid supplied at the inlet port is directed through the diverter to the first outlet port, and a second position, at which fluid supplied at the inlet port is directed through the diverter to the second outlet port.

40. A diverter in accordance with Claims 38 or 39, in which the inlet and outlet ports are co-planar.

41. A diverter in accordance with any one of Claims 38 to 40, in which the diverter comprises a body to which the inlet and outlet port(s) are connected.

42. A diverter in accordance with Claim 41, in which the spool moves within the body and the inlet and outlet port(s) are spaced around the perimeter of the body.

43. A diverter in accordance with any one of Claims 41 to 42, in which the spool and an interior portion of the body cooperate to guide non-rotational sliding of the spool within the body.

44. A diverter in accordance with any preceding claim, in which the spool is provided as an elongate member having two, sealed, opposing ends with a perimeter wall extending there between.

45. A diverter in accordance with Claim 44, in which the perimeter wall has an inlet orifice and a spaced outlet orifice.

46. A diverter in accordance with Claim 45, in which the outlet orifice is preferably spaced radially from the inlet orifice around the perimeter of the perimeter wall and is spaced axially from the inlet orifice.

47. A fluid distribution system or a fish farm feeding system or a method of distribution of a fluid or an address decoder or a distributor or a diverter substantially as herein before described with reference to one or more of the accompanying drawings.