ESTATE WATER TURBINES
‘MICROHYDRO’
With nominal outputs up to 50 kW, these units have been specifically designed as direct replacements for diesel generating sets, in that they provide a fully governed single or three phase AC supply. All are controlled using the latest versions of our award winning ‘Electronic Load Governing System’. They are similar to the ‘PICO’ Series, in that they are of modular construction, so that they can be adapted quickly and easily to fit a far wider range of site and application.
The high head ‘Hillstream’ sites are harnessed using mainly vertical shaft milti-jet ‘Pelton’ wheels and ‘Turgo’ type runners in a square casing. Highly adaptable and reliable, we have supplied these to projects around the world for over thirty years. The lower head ‘Millstream’ sites are developed using circular cased ‘Armstrong’ and ‘Propeller’ turbines. The very low head sites employ ‘Open-Flume’ or ‘Bulb-Type’ propeller turbines.
We usually fit brushless synchronous generators because it allows the plant to be operated when there is a power cut, something that is not usually possible with an induction generator. All are well insulated and able to withstand accidental over-speeds. Protection against dangerous ‘over-voltages’ associated with over-speed conditions is also standard.
MICROHYDRO TURBINE GALLERY
"Lochourn" (VSO PE 30/240)
This is a vertical shaft overhung Pelton turbine that is well suited to mountainous areas. If the head is not restricted, it can be chosen to match the turbine to give the correct operating speed for a standard 'pitch-circle'. Within reason the 'pitch-circle' of a Pelton (tangential flow turbine) can be altered to match the head. Our standard runners are designed for a pitch-circle to jet ratio of 8:1, this can however range from 4:1 up to 20:1 without significant impact on the overall efficiency.
"Buthan" (HSO PE 30/240)
A slightly more expensive version than the "Cambrian" but easier to service since the runner and jet is accessible through a large removable side panel. The water flow is controlled with a manually operated spear-valve. The turbine illustrated had to be dismantled into small components for the three day walk to the installation site!
"Idris" (HST PE 40/350)
A traditional twin bearing Pelton turbine with spear-valve and deflector control of the water. This turbine is used to recover energy from the inlet supply pipe to a water treatment works. A significant advantage of this type of turbine for this application rests on its ability to control the flow rate and the power output independently, so an electrical shutdown does not stop the flow to the works.
"Lauriston" (VSB PE 50/400)
One of our most popular turbine designs, having been installed in North Wales, Scotland, Sri Lanka and the Amazon Rainforest. The smallest economic output for this size is 10 kW and is illustrated here. Other versions have been rated up to 80 kW. The generator is often 'packaged' with the turbine bed-frame to make installation easier.
"Precelli" (HXF 400/125)
Installed in a water treatment works to control the inlet flow and turn surplus pressure into electricity, this cross-flow turbine in manufactured entirely in stainless steel. The runner is an investment casting to overcome the common problem of blade failure due to fatigue, found in cheap fabricated cross-flow turbines. This design has largely been superseded by our own 'Axial-flow Armstrong Turbine' that also uses a fully cast stainless steel runner.
"Dunblane" (HXF 400/800)
Working from six metres of fall at an old mill site, the turbine utilises about 2 metres of vacuum below the turbine. The runner is a stainless steel 'lost-wax' casting to overcome the problems usually encountered with fabricated cross-flow runners. This type of turbine has largely been superseded by our own design of axial flow 'Armstrong' turbine.
"ARMSTRONG" (VCB 300)
This is an investment cast stainless steel nozzle ring from our axial flow impulse turbine. There are several arrangements of flow control, some of which give a minimum flow of around 15% of the full rated flow. The design is exceedingly strong, especially when compared to the cross-flow.
"TUBULAR" (TP 350)
Installed in the same type of circular casing as the 'Armstrong', these turbines give an efficiency of over 80% at a much higher shaft speed, but the flow variation is limited to variable speed operation and a flow variation of no more than 20%. Multiple turbines are used to cater for major variations in flow, being more efficient and cheaper than a single Kaplan turbine.
"Elbo" (AP 500)
Installed as single or twin units like the one illustrated, these turbines are simple, efficient and reliable. The novel water-lubricated steady bearing removes the risk of water pollution from leaking oil, whilst giving a life that is many times longer than cutlass type bearings.
"KAPLAN" (KA 700)
Where variation in flow is required from a single turbine, we can supply our Kaplan turbine. The runner and all working parts including the variable guide vanes are made of stainless steel.
Illustrated above is a selection of plants rated between 5kW and about 50kW that we have built over the years. There are many other combinations that we can supply to match your specific requirements, so we would be delighted to hear from you. The array of designs may appear a little daunting, but all you have to do is tell me about your site and what you want and I will do the rest.
Our aim is to supply quality turbines, mainly in stainless steel that are the same price as mild steel alternatives and with efficiencies and design lives that are significantly better than our competitors.
We lead the field in small turbine designs and with innovations such as 'electronic load governing' that are now used around the world. We plan to continue for the next 200 years with many more innovations and products that will still be serving your grandchildren.
Rupert Armstrong Evans
Managing Director