The invention relates to a rotor apparatus, for example a rotor apparatus used to extract energy from a fluid flow, or add energy to a fluid flow. Such a rotor apparatus may be used as pumps for conveying fluids or as turbines for receiving energy from a fluid flow.

A flowing fluid possesses kinetic energy due to its motion. Naturally occurring fluid flows can be found in tidal currents, coastal or oceanic currents, river flows, thermal currents, air currents and elsewhere. Fluid flows can also be generated by man directly or indirectly. For instance, secondary fluid flows may be generated upstream or downstream of an obstacle placed in a naturally occurring fluid flow such as a dam in a river. Fluid flows may be generated by the transport of a fluid in a pipeline or by a machine such as fluid flows in a fluid system installed on a train, on a ship or on an automobile. A rotor apparatus is used to generate rotational kinetic energy from fluid flows, typically for power generation, or to transfer kinetic energy into the fluid flow, for example, when pumping.

WO 2005/017394 discloses a system for generating energy from tidal currents in which a turbine can be selectively rotated in a housing in order that it can turn through 180° depending on the prevailing direction of water flow, i.e. to allow for incoming and outgoing tides to turn the rotor of the turbine efficiently.

Viewed from a first aspect the invention provides a rotor apparatus comprising a passage for flow of fluid, a rotor mechanism for interacting with the fluid flow and a valve arrangement for controlling the flow of fluid through the passage, the valve arrangement including a valve body holding a valve seat and a valve member that moves within the valve body to open and close the valve, wherein the rotor mechanism is mounted within the valve member.

Thus, a combined rotor and valve device is provided where the rotor mechanism is located within the valve mechanism. The proposed arrangement eliminates the need for separate valve/turbine/pump components, thus reducing the required footprint and cost. The valve member can be used to orient the rotor mechanism as well as being able to open and close the passage to allow fluid flow and to prevent fluid flow as necessary. In contrast to the features of the prior art system of WO 2005/017394 there is a valve arrangement that houses the rotor mechanism, with a valve member rotating to open and close the valve. There are numerous benefits to such a system.

For example, the rotor apparatus may be used in unidirectional hydropower applications such as high, medium, low and ultra-low head hydro where the rotor mechanism acts as a turbine for example, installed in a dam, dyke, run of river or wave capture installation. The rotor apparatus has as an integral valve that is able to switch off the turbine, for example as a safety mechanism in times of overload or for planned maintenance. The rotor apparatus may be used in bidirectional hydropower applications such as high, medium, low and ultra-low head pumped hydro where the rotor apparatus acts as a turbine and also as a pump. This occurs where the fluid moves from a higher first reservoir to a lower second reservoir and in doing so drives the turbine, thereby converting the potential energy of the fluid to kinetic energy extracted at the turbine. At certain times of the day the rotor apparatus may be run in reverse so that it acts as a pump to pump the fluid from a lower second reservoir to a higher first reservoir, thereby converting kinetic energy from the pump to potential energy in the fluid. For this application there may be more than one first or second reservoir. In this case the rotor apparatus has an integral valve that is able to switch off the combined turbine/pump between fluid movements or for planned maintenance.

In a preferred arrangement the rotor mechanism may be arranged to rotate with the valve member, alternatively it may have the ability to move rotationally independently of the valve member. Thus, the axis of rotation of the rotor mechanism (and hence its shaft) may rotate, for example about a normal to the axis, and this rotation may be about the same axis as the axis of rotation of the valve member. With this feature the apparatus may

advantageously be used in bidirectional flow installations such as tidal power generation. A 180° rotation of the valve or a 180° rotation of the rotor's axis of rotation can move the rotor mechanism from a configuration optimised for one direction of flow to a configuration optimised for the opposite direction of flow at a different time of the day..

The ability to close the valve gives further advantages in tidal power installations such as in tidal barrages. The valve member may be closed to allow the upstream tide to be held back until the downstream tide has receded, thus maximising the head difference (and the associated power extraction) for a rotor mechanism acting as a turbine when the valve is opened again.

The rotor apparatus may also be used in flood control, for instance, following a flooding incident that breaches a dam, a dyke, run of river, wave capture or tidal barrage installation. When the combined rotor and valve apparatus is installed in a dam, dyke, run of river, wave capture or tidal barrage installation, the valve may be opened after flooding and the rotor mechanism may be used as a pump to rapidly eject the flood water.

In the case where the rotor mechanism can also be rotated then the rotor apparatus could be used in a pumping mode in flood control or alternatively in a power generation mode. Thus, a single combined valve and rotor apparatus can stop the flow, reverse the flow by pumping, or obtain energy from a flow by acting as a turbine.

The rotor apparatus may be a part of a pipeline system for pressure recovery or pressure addition, for instance, in large fluid distribution networks such as for potable water or industrial chemicals that may require additional pumping or pressure reduction. The valve may be used for flow control, the rotor mechanism may be utilised as a turbine to extract energy from the pipeline or the rotor mechanism may be used as a pump to add energy to the pipeline. The valve member may be rotated to close the flow passage in order to switch between different flow patterns for the pipeline system. In addition, where the rotor mechanism can be rotated or rotates with the valve member, then this may allow the system to change the configuration from a pump to a turbine for different flow requirements.

The rotor apparatus may be used to extract energy in free stream tidal flows where the flow from an incoming tide may be guided into the rotor apparatus by appropriately shaping the valve body to act as a collector. In this case, when the tidal flow reverses direction the rotor mechanism and the valve member can be rotated 180° to align the rotor mechanism in the most optimum direction for the turbine to extract power. In an emergency, the rotor mechanism may also be aligned to act as a pump in order to reduce the effects of an approaching freak wave/tide such as a tsunami. This could be achieved by pumping large quantities of fluid towards the approaching freak wave/tide thus disrupting flow mechanics of the wave/tide and allowing it to break up before reaching an area where it may cause damage.

The rotor mechanism may have one or more blades, preferably a plurality of blades arranged for exchanging kinetic energy with a fluid flow, converting between rotational energy at the rotor and kinetic energy within the flow of fluid. The rotor mechanism may have a unidirectional arrangement optimised for either pumping or for use as a turbine. A bidirectional type rotor mechanism could also be used.

In some preferred embodiments the rotor mechanism comprises a unidirectional or bidirectional rotor arrangement depending on the blade design, for example a pair of contra- rotating rotors mounted on the same axis of rotation. The contra-rotating rotors may face one another such that fluid exiting one rotor will then enter the other rotor. This provides an effective unidirectional or bidirectional rotor mechanism depending on the blade design and there is inherent torque balancing that avoids the need for a specially arranged bracket that would hold out of balance torques/forces. In addition as the power/energy transfer is shared between two rotors then cheaper, lower strength materials can be used. The use of two contra-rotating rotors also allows for the diameter of the rotor to be reduced paired to an equivalent single rotor mechanism. This can be a particularly important advantage since when the rotor mechanism is held within a valve member then the size of the rotor mechanism is a constraint on the size of the valve member. It can be an advantage in many cases to minimise the size of the valve member for a given power rating of the rotor mechanism.

With a rotor mechanism capable of handling bidirectional flow there may be no particular need for rotation of the rotor mechanism through 180° to allow for pumping in different directions or use as a turbine for different flow directions. Hence with a bidirectional rotor mechanism the rotor apparatus may have a fixed (i.e. non-rotating rotor mechanism) and/or a rotor mechanism that only rotates in a 90° turn with a valve member that also rotates by only 90°, as discussed below. Thus, in some examples the rotor mechanism either cannot rotate or will only rotate through a maximum of 90°.

The valve may take any suitable form. A preferred arrangement uses a ball valve and hence the valve seat acts as a cup holding a ball-shaped valve member, with the rotor mechanism supported within the ball shaped valve member. Alternatively, a barrel-shaped valve member or a conical valve member could be used. In some example arrangements, as discussed above, the valve member may be arranged to rotate by 180° or for full 360° rotation with the rotor mechanism also preferably rotating by 180° or 360°, either fixed to the valve member or rotating independently of the valve member, optionally with a different degree of freedom of rotation. In other example arrangements, the valve member may have only a 90° turn, allowing it to be open or close but not to reverse direction. With only a 90° turn the construction of the valve can be stronger and there is greater freedom in designing the supports for the rotor mechanism, since with some designs only a half of the valve body needs to hold the valve seat and allow for movement of the valve member. In the case of a 90° turn the rotor mechanism does not need to rotate with the valve, but it can optionally do so. It may be that it is easier to support the rotor in a manner that rotates with the valve if there is no relative rotation. Alternatively the valve may have a 90° turn, with the rotor mechanism being able to rotate by 180°, for example as with the rotor disclosed in WO 2005/017394. This allows for opening and closing of the flow passage, with a strong valve arrangement, and also with the ability to switch directions of the rotor mechanism meaning that a bidirectional turbine is not needed for bidirectional use of the apparatus.

The rotor apparatus may be orientated in any direction, for instance, the rotor apparatus may be orientated with its longitudinal axis horizontally or vertically or any orientation in between.

The transfer of rotational energy from the rotor apparatus to the generator may be facilitated by an intermediate gearbox that transfers energy from a connected rotor (or from the connected rotors of the contra rotating rotor mechanism). In a preferred arrangement, the gearbox may be coupled to an input/output shaft extending along the axis of rotation of the valve member, i.e. which may be perpendicular to the main shaft of the rotor(s) of the rotor mechanism. The gearbox may be a simple bevel gear or a more complicated gearbox with adjustable gearing. The gearbox may be connected to the rotor mechanism and located outside of the valve mechanism and connected to an externally connected generator, the generator in this case may be a fixed speed or a variable speed generator. The gearbox may be connected to the rotor mechanism and located within the valve mechanism, thereby transferring rotational energy out of the valve mechanism and the valve body to an externally connected generator, the generator in this case may be a fixed speed or a variable speed generator. Alternatively, a direct drive connection may be used whereby the rotor/s of the rotor mechanism may be connected directly to the generator, the generator in this case may be a fixed speed or variable speed generator. In this configuration it may be advantageous to house the generator within the rotor/s. For a rotor mechanism with contra rotating rotors a single generator connected to both rotors may be used or an individual generator may be connected to each rotor. In all cases, the rotors of a contra rotating rotor mechanism may rotate at the same rotational speed or different rotation speed depending on the required output.

The rotor apparatus may comprise multiple valves with multiple rotor mechanisms operating with several flow passages in parallel. This can provide multiplication of design flow rates whilst maintaining the same pressure. In addition, multiple valves with multiple rotor mechanisms may be used in series to provide successive pressure boosts or successive pressure extraction whilst maintain the same design flow rates.

One particularly preferred arrangement uses a rotor mechanism as described in WO2012/098363. The use of this rotor mechanism, having two contra-rotating rotors as described above, in combination with integration of the rotor mechanism into a valve member, provides particular advantages since the rotor mechanism of WO2012/098363 is highly efficient and compact.

Thus, the rotor mechanism may comprise a first rotor mounted for rotation about an axis of rotation in a first direction of rotation, the first rotor having at least one helical blade with a pitch that decreases in a direction along the axis of rotation; and a second rotor mounted for rotation about the same axis of rotation in an opposite direction of rotation and having at least one helical blade with a pitch that increases in the same direction along the axis of rotation, wherein fluid exiting the first rotor is passed to the second rotor.

Since the helical pitch of the helical blade is decreased in one direction each rotor possesses an optimum flow direction, which is from the larger pitch end to the smaller pitch end. Fluid entering parallel to the longitudinal axis and head-on to the larger helical pitch end would meet less of a resistance and would be gently guided into the rotor. As the fluid passes along the helical blade the decreasing pitch ensures efficient extraction of energy from the flow. Fluid could still flow parallel to the longitudinal axis and head-on in the non- preferred direction but power extraction would not be optimal since much energy would be lost in initially aligning the oncoming fluid flow to the angled rotor blades. Thus,

conventionally rotors are designed with a preferred flow direction. In situations where the flow direction reverses prior art arrangements might be provided with means to re-align with the new flow direction, such as a turret mounting or a tethered float in a flow or a change in blade angle by some means.

When fluid exits a unidirectional helical biaded rotor the fluid will possess both a longitudinal and radial component and that this radial component will be well suited for entering the smaller helical pitch end of another unidirectional helical biaded rotor, when the two rotors have blades that turn in the same direction as the pitch decreases (i.e. both rotors having clockwise blades as the pitch decreases or both rotors having anticlockwise blades as the pitch decreases). Thus, in the second rotor the fluid flow direction may enter from the smaller helical pitch end and flow towards the larger helical pitch end. The resulting power extraction would be the same as the initial case but in reverse and the fluid would exit the rotor with only a longitudinal component. Since the two rotors are contra-rotating and oppose one another, fluid can flow in the opposite direction with the same result. Hence, the two- stage rotor of this aspect enables energy to be extracted from flows in either direction along an axis without compromising the level of power production. A preferred embodiment is a rotor mechanism for extracting energy from bidirectional fluid flows such as tidal flows, preferably by production of electricity, thereby the rotor mechanism functions as a tidal turbine. A suitable bidirectional liquid flow might also be generated due to the regular back and forth or up and down movement of a ship or automobile.

Preferably, the first and second rotors have opposed ends that are of the same diameter. The first rotor and/or second rotor may be a cylindrical rotor having a blade formed by a cylindrical helix. In preferred embodiments the first rotor and/or second rotor have a blade or blades formed by a surface extending between inner and outer conic helixes, the conic helixes each having a pitch that decreases as the radius of the helix increases. In the preferred embodiment where both the first rotor and the second rotor comprise a blade or blades formed between conic helixes, the two rotors have the large diameter ends opposing one another and being of the same diameter.

Preferably the first rotor and the second rotor have a blade or blades of the same shape formed by similar conic helixes. This ensures maximum bidirectionality since an identical fluid flow can enter the two-stage rotor mechanism from either end with the same resulting power take off.

For all cases where the rotor mechanism comprises a pair of contra rotating rotors, the first and second rotors have ends opposing one another such that fluid flows from one rotor to the other. In some cases the opposing ends are directly opposing, i.e. with a minimal gap in between the two rotors. This makes best used of the radial component of the flow exiting one rotor and entering the other. However, in some applications, to reduce the danger to aquatic life, the gap in between the two rotors may be increased to reduce the chopping effect between rotors. Then aquatic life may pass through the device unharmed by being carried along by the swirling flow.

The rotor mechanism may comprise a valve body about the first and second rotors. The valve body preferably supports the rotors for rotation about the axis of rotation. The valve body may be designed to perform various functions. For instance, the valve body may be designed purely to house the rotor mechanism and provide support by way of mechanical bearings, magnetic bearings or some other type of active or passive bearing system which allows the rotors to freely rotate with low friction. A sealing arrangement such as lip seals, labyrinth seals or some other type of sealing arrangement may also be in place to prevent the liquid flow from reaching the bearings or electrical components in the rotor housing. Or, some of the liquid flow may be directed towards the bearings and heat exchangers of electrical components and used as coolant in demanding applications.

The valve body may also enclose generator parts, control systems and suchlike. Any suitable shape of valve body may be used. In a preferred embodiment, the valve body has an inlet section and an outlet section. The valve body may be used to enhance the performance of the rotor mechanism. The inlet geometry of the valve body may be designed to increase the linear velocity of the liquid flow as it enters the rotor mechanism entrance through use of a convergent section or some other geometry. Since the power available from the liquid flow is proportional to the cube of the liquid flow velocity, this provides an effective means of increasing the amount of available energy. The outlet of the valve body may also be designed to slow down the liquid flow in a controlled manner through the use of a divergent section or specially designed outlet geometry so that viscous and turbulence losses are minimised and the fluid is gently returned to the main bulk of fluid flow with minimal disturbance. The invention also extends to a method comprising use of the rotor apparatus as a turbine or for pumping fluid. The method may include rotating the valve member of the rotor apparatus in order to close the flow passage when it is desired to block flow through the flow passage. The valve member may be rotatable by 180° or more, or in some examples by only 90°. This method may use a rotor apparatus with any of the features discussed above.

The various advantageous applications of the rotor apparatus described above may provide preferred methods of use of the rotor apparatus. Thus, the method may be a method for unidirectional or bidirectional hydropower applications such as pumped hydro, for tidal power generation, for flood control, and/or as a part of a pipeline system for pressure recovery or pressure addition, for instance, in large fluid distribution networks such as for potable water or industrial chemicals. The valve may be used for flow control, the rotor mechanism may be utilised as a turbine to extract energy from a fluid flow or the rotor mechanism may be used as a pump to add energy to a fluid flow.

The method may include rotating the rotor mechanism of the rotor through 180° in order to change the direction of operation of the rotor mechanism for pumping or for use as a turbine in both directions of flow along the flow passage.

The method may include rotating the valve member in order to close the flow passage for the purpose of building up a head difference between fluid at either end of the flow passage, for example when using the rotor apparatus as a tidal turbine the valve may be closed for holding up an upstream tide until a downstream tide has receded. The rotor mechanism may be switched from operation as a turbine to operation as a pump in order to remove floodwaters or to operate in a pumped hydro application or to add energy to a pipeline application.

Certain preferred embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 depicts a rotor apparatus with a contra-rotating rotor mechanism and a ball valve rotated at 0° allowing fluid flow through the valve;

Figure 2 depicts the rotor apparatus of Figure 1 in a shutdown condition with valve rotated at 90 deg;

Figure 3 depicts the rotor apparatus with the valve rotated at 180 deg, in this configuration having a contra rotating turbine;

Figure 4 depicts an alternative configuration with the inclusion of an access port; and Figure 5 depicts an alternative configuration with a four way (or more) configuration whereby two or more pipe networks may be connected.

Figure 1 shows a rotor apparatus with a contra-rotating rotor mechanism having two rotors 7, 8 and a valve member 4 taking the form of a ball valve member 4 rotated at 0° allowing fluid flow through the valve body 5. A section is removed from the valve member 4 and the valve body 5 to allow visualisation of the internal parts of the device. A

housing/plinth 1 is shown schematically. This housing/plinth 1 may form the supporting structure for the rotor apparatus. A motor/generator 2 and optional variable speed rectifier (not shown) are coupled to the rotor mechanism 7, 8 and arranged to drive or be driven by the rotor mechanism 7, 8 when it acts as either a turbine or a pump. A stepper motor or pneumatic/hydraulic actuator 3 is coupled to the valve member 4 and provides for valve actuation. The fixed valve body 5 provides support to the movable valve member 4 and allows for connection to external flow passages, such as pipework or flow channels in hydropower installations, dykes, dams, run of river, wave capture and tidal barrage installations, for example. The contra rotating rotors 7, 8 extract or input energy through a gearbox 6. The rotor mechanism may have features similar to those described in

WO2012/098363.

An example of the flow direction in turbine mode is indicated by the black solid arrows and the flow direction in pump mode is indicated by the black dashed arrows. The flow passes through the device around the rotors 7, 8 through the inlets/outlets 9, 10.

Whether the device operates in turbine or pump mode, and in what direction, depends on the orientation of the valve member 4 and the direction of rotation of the rotors 7, 8. In this configuration, the rotor mechanism 7, 8 is rigidly coupled to the valve member 4 by the gearbox 6 and its supports and hence the shaft of the rotors 7, 8, as well as the gearbox 6, rotate with the valve member 4. Thus, the contra rotating turbine/pump can accept turbine flow in either direction or pump flow in either direction through inlets/outlets 9 & 10 as the valve member 4 part of the valve may be turned a compete 360° by the stepper motor or pneumatic/hydraulic actuator.

In the example of Figure 1 the valve member 4 and valve body 5 are a ball type of valve, but it is equally possible to utilise a cylinder or other shapes depending on

manufacturing considerations. In addition, various seals may be used to seal leak channels and valve member 4 and fixed valve body 5 may be lubricated, self-cleaning and/or made from material such as PTFE with a low coefficient of friction. It will also be appreciated that a full 360° rotation is not essential. In fact there can be advantages in permitting only a reduced degree of rotation. Thus, in some embodiments the valve member 4 is only permitted a 90° turn, or optionally a 180° turn, with the shape and interconnection of the valve member 4 and valve body 5 adjusted accordingly. The design for the valve member 4 and valve body 5 can be based on conventional valve structures with the addition of the necessary modifications to permit the rotor mechanism 7, 8 and gearbox 6 to be housed within the valve member.

Figure 2 shows the same rotor apparatus in another configuration, in which the stepper motor or pneumatic/hydraulic actuator 3 has provided valve actuation of the valve member 4 has rotated it 90° from its original orientation in Figure 1 , such that the valve is now firmly closed at its inlets/outlets. As the rotor mechanism 7, 8 is connected to the valve member 4 by the gearbox 6 and its supports, it rotates with the valve member 4 as shown. As indicated in Figure 2, there is now no flow at the inlets/outlets 9 & 10.

Figure 3 shows the same rotor apparatus with the valve member 4 rotated 180°s from its original orientation in Figure 1 , such that the valve is now open again at its inlets/outlets 9, 10. As the contra rotating turbine/pump is connected to the valve member 4 by the gearbox 6 and its supports, it rotates with the valve member 4 as shown. The flow direction in turbine mode is indicated by the black solid arrows and the flow direction in pump mode is indicated by the black dashed arrows and the flow passes through the device around the rotors through the inlets/outlets 9 & 10.

Figure 4 illustrates an additional feature that may be incorporated in the rotor apparatus. The fixed valve body 5 may be modified to include an access port 11 to allow access to the rotor mechanism 7, 8 and gearbox 6 when the valve member 4 is closed.

Thus, the access port 1 1 may be placed at a point on the valve body 5 that is perpendicular to the flow passage between the inlet/outlet ends 9, 10. This would allow access for extraction and maintenance of the t rotor mechanism 7, 8 and gearbox 6 without requiring the whole valve apparatus to be removed from any connecting pipework or flow channels thus saving considerable labour costs and downtime.

Figure 5 illustrates another optional feature that may be incorporated in the valve apparatus. In this arrangement an additional inlet/outlet pair 14, 15 is provided with corresponding pipe connections 12, 13, with the additional inlet/outlet pair 14, 15 being at 90° to the first set of inlet/outlet 9, 10. Thus, when the valve member 4 is in the 90° position as in Figure 2 then a first flow passage between the first set of inlet/outlet 9, 10 is closed and a second flow passage between the additional inlet/outlet 14, 15 is opened. With this configuration the rotor apparatus may be used with two or more pipe networks and it is able to switch to turbine or pump mode for each individual pipe network. I

In an alternative configuration not shown, the valve member 4 part of the valve rotates and closes the valve but does not rotate the gearbox and its supports 6, and the turbine/pump rotors 7 and 8 with the valve member 4. In this configuration the valve member 4 works independently. As noted above, there need not be a 360° movement of the valve member 4 and this also applies in the case where the rotor mechanism 7, 8 and gearbox 6 do not move with the valve member 4. In one example the rotor mechanism 7, 8 and gearbox 6 are fixed and the valve is a 90° turn valve where the valve member 4 moves by only 90° to control flow through the rotors.

In all of the above figures, the rotor mechanism 7, 8 does not need to be a contra rotating arrangement. Instead the rotor apparatus may include a single rotor turbine, single rotor pump or single rotor turbine/pump. In a configuration of this type, the single rotor turbine may accept flow in a single direction if it is a unidirectional turbine or both directions if it is a bidirectional turbine. The pump may be able to pump flow in a single direction if it is a unidirectional pump or in both directions if it is a bidirectional pump. An arrangement where the rotor turns through 180°s is of benefit when a unidirectional rotor is used, since it can then act as a turbine or as a pump in either direction.

However, the use of a contra rotating pair of rotors 7, 8 has additional benefits, such as inherent torque balancing requiring a minimal plinth construction for out of balance torques/forces. In addition, since the power is shared by both turbines, the turbine blades may be designed for reduced strength, thereby reducing material costs. Finally, the diameter of the turbine/pump may be reduced since twice the power is taken out or added in a smaller cross sectional area.