GB2505279A

GB2505279A - Micro water turbine with submerged housing

Info

Publication number: GB2505279A
Application number: GB1310128.2A
Authority: GB
Inventors: Anthony Glynn; James Sherlock
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-06-27
Filing date: 2013-06-06
Publication date: 2014-02-26
Also published as: IE20130188A1; GB201310128D0; WO2014001929A2; WO2014001929A3; GB2503476A; GB201211441D0

Abstract

A small scale water turbine unit comprises a horizontal axis helical turbine 19 mounted in a housing with base and top sections 2, 4 which define an elongate water channel 9, 10. The upper surface 4 allows water to flow over the unit to create downward pressure on it. The channel may be tapered towards the turbine, and may include front 5 and rear 6 grilles. There may be a braking system to protect the turbine from excessive flow speed, comprising a plate 20 which is moved by the flow to restrict the water channel opening (figure 16). The unit may comprise a depth gauge and means to automatically adjust the height of the unit. The turbine may be able to operate in as little as 100mm of water, at speeds as low as 0.3m/s.

Description

"A water turbine unit"

Introduction

The invention i-elates to a water turbine unit for generating electricity from flowing water.

Hydroelectric power is generated ushig water as an energy source. Using water to generate electricity is a sustainable alternative environmentally friendly way of obtaining energy. Different hydro turbines are commercially available, however it is still uncommon to see water turbines in everyday use.

There is a need for an improved small scale water turbine which is easy and economical to instafi and operate and which provides a cost effective means of harnessing energy.

Statements of Invention

According to the invention there is provided a small scale water turbine unit comprising a base section comprising an elongated water channel; a main body section comprising a helical blade turbine; and a cover section, wherein the unit is a low profile unit allowing water to flow over the unit and create downward pressure on the unit.

In one embodiment of the invention the turbine comprises a staged helical blade turbine.

Preferably the staged helical blade turbine compnses a p'urality of blades. Most preferably the staged helical blade turbine comprises three sections with four blades on each section.

In one embodiment of the invention the sides of the water channel are substantially straight at the outer edge near the opening of the channe' and then taper inwards towards the turbine. Preferably the opening of the channel tapers to a width substantially equal to the length of the helical turbine blade.

In one embodiment of the invention the roof of the water channel is tapered.

In another embodiment of the invention the floor of the water channel is tapered.

In one embodiment of the invention water flows though the water channel providing a direct flow of water directed to just below the axle of the turbine.

In one embodiment of the invention the exit at the rear of the unit comprises an opening equal in width to the length of the turbine blade, In one embodiment of the invention the cover section lies close to the top of the turbine blade to eliminate negative forces from the back of the blades, remove any turbulence in the water flowing over the top of the blade, reduce the weight on the back of the blade as it spins upwards through the water and increase the efficiency of the blade. Preferably there is a maximum space of 15 mm over the top of the turbine blade.

In one embodiment of the invention the cover section comprises a braking system.

Preferably the braking system comprises a spring operated baffle having two blades.

most preferably one of the blades pivots on the outside of the unit and the other blade pivots on the inside of the unit.

In one embodiment of the invention the cover section comprises a front and rear grill or mesh to cover and protect the water channel.

In one embodiment of the invention the main body section comprises a turbine, generator, gear system, seal bearings and sensors.

In one embodiment of the invention the cover section is detachable. Preferably the cover section comprises a hydro foil design.

In one embodiment of the invention the main section is detachable from the base section.

In one embodiment of the invention the base section is fixed to a river bed.

In another embodiment of the invention the base section comprises adjustable legs.

In one embodiment of the invention the unit comprises a depth gauge attached to a motor to automatically adjust the height of the unit. The depth gauge optimises the performance height of the unit. Preferably the depth gauge is a float switch.

In one embodiment of the invention the unit comprises an alarm and monitoring means to remotely monitor the functioning and performance of the unit. Preferably the alarm and monitoring means comprises an rpm monitor, a current sensor and a power output sensor.

The alarm system is preferably located within the generator unit.

In one embodiment of the invention the water turbine unit is capable of operating in as little as 100mm of water.

In another embodiment of the invention the water turbine unit is capable of operating with a water flow rate of as low as 0.3 meters per second. Preferably the unit is capable of generating at least 100 watts of energy. Most preferably the unit is capable of generating greater than 700 watts of energy.

Brief Description of the Invention

The invention will be more clearly understood from the following description thereof with reference to the accompanying drawings in which: -Fig. I is side perspective view of the small scale water turbine unit of the invention; Fig. 2 is a side view of the water turbine unit of the invention; Fig. 3 is a view from below of the water turbine unit of the invention; Fig. 4 is a top plan view of the water turbine unit of the invention; Fig. 5 is side perspective view of the base section of the water turbthe unit of the invention; Fig. 6 is a view of the base section from the rear; Fig. 7 is a view of the base section from the front; Fig. 8 is a cross sectional view from the front to the rear of the water turbine unit of the invention; Fig. is front perspective view of the water turbine unit according to another embodiment of the invention; Fig. 10 is rear perspective view of the water turbine unit according to another embodiment of the invention; Fig. ii is a cross sectional view from the front to the rear of the water turbine unit according to Figs. 9 and 10; Fig. 12 is side perspective view of the staged helical turbine blades of the water turbine unit of the invention; Fig. 13 is side view of the helical turbine blades of the invention; Fig. 14 is a schematic view of water flowing through the helical turbine blades; Fig. 15 is an exploded view of the different sections of the water turbine of the invention; Fig. 16 is a schematic view of the baffle breaking system on the cover section of the water turbine of the invention in its open flow position (a) and restricting flow position (b); Fig, 17 is side perspective view of a water turbine unit according to another embodiment of the invention; Fig. 18 an exploded view of the component parts of the water turbine unit of Fig. 17; Fig. 19 is a front view (a) and a cross sectional view along the line C-C (b) of the water turbine unit of Fig. 17; Fig. 20 is a top view of the base section water turbine unit of Fig. 17; Fig. 21 is a cross sectional view of the cover section of the water turbine unit of Fig. 17; Fig. 22 is a side view of the main body section of water turbine unit of Fig. 17; Fig. 23 is a further side view of the main body section of the water turbine unit of Fig. 17 and cross sectional views along lines B-B and C-C; and Fig. 24 is a detailed view of the working parts of the main body section of the water turbine of Fig. 17.

Detailed description

The use of water energy is a valuable resource. In order to ensure that the resource is well managed there are various conditions that need to be met in order to operate a water turbine in rivers or waterways. A water turbine should not pollute the river, disturb the ecothgy in the river and not be harrntiil to fish or wild life.

The present invention comprises a smafi scale water turbine unit that is simple in design and easy to be installed and maintained, The unit may be very easily lowered into position in a river. The small dimensions of the unit ensure that the unit does not obstruct a rivers natural flow. The unit is capable of operating in less than 400mm of water. The unit is capable of operating in as little as 100mm of water. The unit may be fully submerged or partially submerged to operate. The water turbine of the present invention is able to give a high output at a low flow rate. The water turbine unit can operate with a flow rate as low as 0.3 meters per second (mis). The unit reaches its maximum output at 2.Srn/s. The small scale water turbine unit of the present invention is capable of generating energy from a very small river or stream. The unit maxiinises the benefits of the current present in all rivers and streams.

The unit avoids any planning issues with wildlife organisations and/or fishery boards.

The small scale water turbine unit of the present invention avoids any high civil costs typically associated with installing hydro turbines. The water turbine unit of the present invention optimises the ability to harness a rivers electricity generating potential. The water turbine unit may be used to harness energy generating an output energy of greater than l00watts.

The water turbine unit I of the present invention comprises a base section 2, a main body section 3 and a cover section 4. The water turbine unit has a low profile design. The cover section 4 is hydro foil designed to keep down force on the cover of the turbine and remove the potential of the unit being lifted from the floor of a river or stream. The front face 5 of the unit has an elongated rectangular sloped or angled face. The sloped face in addition to the low' profile shape of the unit ensures that fish or debris which come in contact with the front face of the unit move easily over the top of the unit and do not get stuck or lodged on the front face of the unit, The cover section 4 comprises a grill or mesh 6 over the elongated rectangular sloped front face 5. The grill or mesh 6 is positioned on the outer edge of the front face 5 of the unit, The grill 6 allows water to flow freely through the unit yet protects the turbine blades from any debris. The grill 6 also prevents and protects fish from passing through the turbine unit, The unit I also has a griH 6 covering the exit 9 at the rear 7 of the unit where the water flows out of the unit. The grill or mesh 6 has bars set up in a vertical manner and the bars are set to the smallest gap applicable and defined by the Fishery Board, Wildlife Association and Environmental bodies ii any country worldwide. This is to protect any wild life that risks injury when near the unit.

The base section 2 comprises legs 8 allowing the unit to be easily levelled in river conditions. Preferably the unit has five legs, one at each corner of the base section and one in the centre. The legs are height adjustable. The height of the legs may be adjusted mechanically by electric motors or increased in height by placing small extension pieces onto the legs.

The base section of the unit comprises a channel 10 for the water to flow freely through the unit. The opening 11 at the front of the unit is wider than the exit 9 at the rear of the unit. The opening Ii at the front has tapered walls to create more force into the turbine blade by directing and funnelling the water into the turbine. The tapered sides have a straight edge Z at the front to stop backwash occurring. Water hitting the angle Y, formed between the straight and tapered wall, is forced in and not returned as backwash.

Fig. 5 shows the flow of water through the tapered channel 10. At the opening of the channel the floor 40 is tapered slightly to facilitate a better flow of water through the unit.

The channel 10 tapers to a width substantially equal to the length of the turbine. The angled channel 10 directs water from the tapered sides and creates a "ftrnncl". The angled sides increase the pressure and velocity of the water to where the turbine blades are located. The exit point 9 is the rear of the unit 1 and water flows through the turbine straight back into the river. The exit point 9 at the rear 7 of the unit I is narrower than at the opening mouth 11 of the unit 1.

The cover section 4 and base section 2 in combination are shaped to increase the channelling or funnelling effect as can be seen more clearly iii Fig. 8. The cover 4 is shaped so as to provide a gradual slope in the roof of the channel 10 from the opening or entrance 11 of the unit 1. The water flowing into the unit 1 is directed to just below the axle of the turbine blades, The combination of the tapered walls in the base section and tapered roof in the cover section creates a "venturi effect" 10 effectively creating positive force onto the turbine blades. This results in an improved output performance.

For larger applications for example in larger rivers the water turbine unit of the invention may be increased in height to provide a larger opening to receive the flow of water. In this instance the floor of the water channel is tapered all the way to the turbine blade as shown in Figs. 9 to 11. This provides an increase in both pressure and velocity within the funnel enhancing the "venturi effect" within the bottom, sides and roof of the water channel.

The turbine blade 19 is a staged helica' design as shown in Fig. 12. The staged helical turbine 19 has a plurality of blades. Preferably the helical turbine has 12 small blades, 4 in each third. The number of blades depends on the location of the water turbine, for example more blades may be required if the turbine is located in veiy fast moving water.

This type of blade design reduces drag and improves the flow of the blade in the water.

As shown in Fig. 12 as water hits the blade 30 at the front, pressure is exerted on the blade causing it to turn. Water is also channelled in the direction of the arrow through the gap marked S. This keeps a positive momentum in the water and exerts more pressure on blade 31. The water then moves through in the direction marked P creating forces and positive pressure on the blade 32.

Fig. 13 is a side view of the staged helical blade of the invention. Fig. 14 shows cross sections of the turbine blade as it moves one rotation showing the flow of water through the blades. As section A spins through the water it is a positive force. In section B water on blade 3lis still exerting positive pressure as the blade is moving upwards through the water, point d has a negative force on it but the water is starting to be forced down the back of the blade into pocket e. Fig. 14 (c) is a negative to neutral pocket but water at point p is being forced onto the front of the blade 30 turning the water into a positive force again.

As the blade starts to spin, it turns a drive gear this in turn spins a slave gear that is connected to the generator. The gears may be adapted to increase or decrease performance of the turbine depending on individual river characteristics, Once the river water has passed the turbine blade the water exits through the rear 12 of the unit 1.

The staged helical blade turbine 19 of the invention helps reduce the loss of natural kinetic water energy to electrical power. The shape of the blade optimises the forces on the turbine in the river and reduces negative forces during rotation. The turbine power is directly transmitted to the generator. In low speed rivers, below 2 m/s the turbine power is indirectly transmitted to the generator. In faster moving rivers the turbine power may be directly transmitted to the generator.

An in-direct drive system uses two gears, the fir st a drive gear connected to the blade axle, the second a slave gear connected directly to the generator. Using an in-direct drive system allows the turbine to use a high RPM Permanent Magnet generator which in turn reduces the initial cogging torque associated with permanent magnet generators. Using a high RPM (600 rpm) permanent magnet generator reduces the initial inertia required to turn the turbine blade, When a gearing system is connected to the axle and generator, the turbine does not need to spin at 600 rpm to reach fts maximum output. Using a gearing system with a ratio of 1 (drve gear connected to blade axle) to 2.25 (connected to the generator) the turbine blade needs to spin 266 times per minute to allow the generator to operate at full output. This is achieved in 2.5 rn/s of water. This also allows for a different gearing ratio in rivers with an average speed of 2.5 mIs. For example gearing ratio of 1:0.8, for every I full revolution the blade makes the generator only revolves 0.8 times.

allowing for a lower output to protect the generator.

A direct drive system is a very simple way of connecting a generator to a turbine blade however for low RPM permanent magnet generators (250 rpm) the initial inertia required to start power generation is far greater. Although the RPM is lower the size of the turbines blade needs to be greater. A direct drive system may be used for high head, deep water sites as the weight of water is far greater.

The main body section 3 is easily detachable from the base section 2 for maintenance.

Fig. 15 shows the different sections, cover section 4. main body section 3 and base section 2.

The main body section 3 comprises a generator 12, gears 13, and bearings 14 as shown in Figs. 23 and 24. The generator is a permanent magnet generator. These are contained in a water tight chamber IS on one side of the main body section 3. On the opposite side of the main body section 3 there is a smaller water tight chamber 25 containing a beanng 16 and a bearing block 17 and water tight seal. Both chambers are held in place by a base plate 18 and the turbine blade 19. Figs. 23 and 24 relate to a water turbine according to another embodiment of the invention however the components of the main body secrion 3 are essentially the same for all embodiments of the invention. The inner workings of the water turbine are the same for all embodiments of the invention.

The gearing system is very simple. It allows site specific optimization of the unit, It consists of a drive gear attached to the axis of the turbine and a slave gear that is attached to the generator. The gear sizes may be changed to optimise the turbines output in any tiow conditions. I0

When the main body section 3 requires servicing, the cover section 4 is easily unscrewed and removed while the unit is still in position in a river. The main body section 3 is then lifted from the base section 2 and simply lifted out of the water and placed on the bank of the river to be serviced. Once servicing is complete the main body section 3 is simply placed back into the base section 2 of the unit, secured in position and the cover section re-bolted onto the unit.

The cover section 4 on the top of the unit 1 is easily detached. This allows the unit Ito be easily serviced and maintained. The cover section 4 reduces the resistance over the turbine blade 19 due to the low volume of water over the top of the turbine blade 19. The cover section 4 allows the water to be directed optimally over the blade so that the turbine blade is working at its full potential, There is a very small are available over the top of the turbine blade. Preferably there is a maximum space of 15 mm over the top of the turbine blade. By covering the top of the blade it removes negative forces from the back of the blades, in addition by having only a small space over the blade it removes any turbulence in the water flowing over the top of the blade and reduces the weight on the back of the blade as it spins upwards through the water. All of this increases the efficiency of the blade. The available area over the turbine blade is cntical to the efficient working of the water turbine of the invention. Preferably the energy output of the hydro turbine unit in optimum conditions is at least 700watts.

In fast flowing rivers over 2.5 mIs the cover section 4 may comprise a baffle 20 as shown in Fig. 16 which acts as a braking system. The baffle is positioned at the opening II of the unit 1 and serves to adjust the volume of water through the unit when required. There are two blades, fixed onto an axis 21 with an angle greater than 90 degrees. The two blades operate under a simple counter weight system to prevent over powering of the unit. One blade 22 pivots on the outside of the unit. When the river is flowing too fast the blade 22 will be forced downwards, The second blade 23 is in the water chamber within the unit. As the blade 22 on the outside is forced down (Fig. 16(b)) due to the rivers flow the blade 23 in the water chamber will move into the water chamber and reduce the volume of water moving through the turbine unit. This in turn reduces the

II

generators output. As the flow of the river reduces and the flow slows down the top blade 22 moves back into its original (vertical position) (Fig. 16(a)) and the second blade 23 moves back to the roof of the water chamber. The resistance on the baffle 20 may be changed to suit the liver and the gear setup. The baffle is changed manually. The baffle comprises a spring enabling the plate to move in and out of position.

The base section 2 is a hollow mould and is weighted in the river by filling it with concrete, water or sand. The legs on the base section allow the unit to be easily positioned without requiring a lot of levelling or preparation work on the river bed.

The base section 2 may be held in position by driving two to four poles into the ground of the river and fastening the poles to the main body of the turbine, The poles may be tixed in any suitable position around the lower body. Preferably the poles are inserted into the holes on the outer corners of the legs 8 of the turbine unit 1.

Figs. 17 to 24 refer to another embodiment of the invention however the gearing system and general workings of the main body section are essentially the same for the water turbine according to all embodiments of the present invention.

In this embodiment of the invention the front side 5 of the turbine unit maybe elevated in comparison to the rear of the unit as shown more clearly in Figs. 16 and 18. By elevating the front 5 of the unit it makes it more difficult for stones or other debris to directly hit the front grill of the unit. In addition elevating the front 5 of the water turbine unit creates a small fall or slope directly into the turbine blade.

Water flows through the grill 6 at the front 5 of the unit, is funnelled along and down the gradual slope and tapered sides of the channel onto the blade of the turbine. As the blade starts to spin, it turns a drive gear this in turn spins a slave gear that is connected to the generator. The gears may be adapted to increase or decrease performance of the turbine depending on individual liver character stics. Once the river water has passed the turbine blade the water exits through the rear 12 of the unit i. In

To install the unit 1 in a river a cable is connected to an inverter that is separate to the unit. Two air hoses are connected to the generator unit to allow for natural air changes in the generator chamber. When the cable and air hoses are connected and brought to land the unit is simply lowered into position below the surface of the river. Any conventional attachment cable and air hoses commonly used for water turbine units may be used. The unit can be placed on the bottom of the river, where it may be levelled using a concrete plinth or shoes to level the unit, Akernatively the unit may be raised from the bottom of the river using shoes/leg extensions.

An alarm system may be connected to the cabling system to alert the iser of the water turbine unit if the unit is interfered with or the unit malfunctions as a result of a break in the current supply. The alarm system is preferably located within the generator unit. The alarm system is a monitoring unit comprising an rpm monitor, a current sensor and a power output sensor. It determines the performance of the unit and allows the unit to be monitored remotely to determine whether it is functioning optimally, malfunctioning or if it is removed or interfered with.

The water turbine unit may be positioned anywhere in a river where the flow velocity is sufficient to generate energy. The water turbine unit can operate with a flow rate as low as 0.3 meters per second and so it may even be located in streams.

The culTent in a river is typically present at approximately 100mm below the surface of the water. Rivers swell at times. The unit of the present invention may automatically adjust the height of itself so that it always benefits from the current. The adjustment process involves utilising a float on top of the water connected to the unit. Servo-motors attached to the unit higher or lower the unit as required.

The turbine unit of the present invention is a slim-line low profile unit. The minimum height of the water turbine unit is approximately 200 mm. Its low profile ensures that it does not encourage debris to gather around the unit. Debris hits the front of the unit and is guided over the top of the unit. All the gears and operating mechanics of the turbine unit are enclosed and protected by the cover section.

Any suitable materials may be used in the manufacture of the unit. The materials need to be capable of long term use submerged in water. The unit is a fight weight unit maiffly manufactured from plastic. The unit is light enough to be handled and positioned by two people. The main body section and cover section may be manufactured from a plastic mould. The pbstic used ensures there are no contaminants in the river. The main body section may be plastic and filled with concrete, water or sand to weight it down in the water. The grills to the front and rear may be manufactured by either moulded plastic of galvanised mild steel. The turbine blade, generator chamber and bearing chamber may be constructed of mild steel. galvanised and dipped or injection moulded plastic. Bio-degradable grease may be used in the inner workings of the unit to ensure no harm to environment The invention is not limited to the embodiments herein before described which may be varied in detail.