Heidra Logorock & water




Optiflow T17 Turgo TurbineVolume Fraction

After analysing the typical flow characteristics of upland sites Heidra recognised the need for a low cost, high performance hydro electic turbine which was able to work at high efficiency over a wide flow range. Heidra has teamed up with a range of highly experienced industrial partners to develop the Optiflow hydro electric turbine.

All components are tested on Heidra's own class 1 or better instrumented test rig to ensure a fault-free reliable turbine that does what we claim it does.

The body of high pressure spear jet, right, is cast in gun-metal brass and the complex geometry parts of the nozzle and internal guide vanes are moulded from a high performance polymer with mechanical properties exceeding those of aluminium and with exceptional wear resistance. The spear itself is manufactured from stainless steel using computer controlled machining methods.

Static Pressure


The figure to the left shows computational results used to help optimise the nozzle orifice geometry to ensure a clean jet separation and minimum jet divergence.

By using sound, industrially leading design processes we ensure maximum efficiency and minimum wear.



Heidra has taken a modular approach to the development so that each turgo turbine can be tailor made to an individual site with a choice of rotor diameter, number of spear jets and operating RPM. A high efficiency asynchronous generator is used to ensure a maintenance free service history. The overall water-to-wire efficiency is around 80%, down to a quarter of the rated total flow capacity.

The development work was performed partly as a contract awarded from RE4D who recognised Heidra's in depth experience in the fields of solid modelling, injection moulding, polymer materials, and computational fluid dynamics (CFD). All of the main components, apart from the generator, are manufactured in Devon and a high proportion of those by companies based on Dartmoor. We are proud to minimise our carbon footprint.

Custom Spear Jets

With increasing demand for larger spear jets, both on new and refurbished pelton/turgo turbines, Heidra now supplies jets based on 4" & 6" diameter inlets. Nozzle diameters are fabricated to suit your flow requirements. All jets can be supplied with electrical DC actuators (12, 24 or 36 V).

Alignment accuacy between axially mating components is guaranteed to be within 0.05 mm, ensuring low friction, excellent jet shape and perfect sealing. The images below depict a recent installation using 2 x Heidra Optiflo Spear Jets customised to fit a refurbished Pelton Turbine.

Fabricated Spear JetsPelton + SpearSpear Jet Comissioning

Control and Grid Connection Units

Heidra works in partnership with JJAutomation to supply assembled and automated control and grid connect units for all types of hydro turbines. Features include:

  • Generator soft start for reliable grid synchronisation.
  • Full Bridge PWM (20 khz) control of actuators to ensure smooth ramp starting and stopping of actuators.
  • Power Factor correction.
  • Touch Screen control.
  • On-Line real-time performance monitoring.
  • Text and E-mail alerts of system under-performance and outage.
  • Full control of abstraction as a function of time of year (e.g. fish migration) and river flow.
  • Power back-up and automated restart in case of grid outage.
  • G59 and G83 compliant

Turgo Turbines

Heidra supplies Turgo turbines, with a 6" inlet to each jet. Turbines are normally designed to be flat belt driven for maximum efficiency.

Turgo Turbine

Rotor + Spear

Heidra has designed and developed a new system of manufacturing the turbine rotor such that each stainless steel blade is individually cast and then assembled into a machined hub. By ensuring appropriate pre-stressing, fatigue stresses are kept to a minimum. The final assembly provides a blade-shaft location tolerance of under 0.1 mm.

Nozzles Partial Rotor


water fall

Heidra Ltd, Littlehurst, Gravel Path, Berkhamsted, HP4 2PQ   Registered in England and Wales Number: 07984621