Low Head, Open Flume Sites

Hundreds of low head mills and weirs are spread across the lowlands of the United Kingdom and Europe. These sites were used for agro-processing and to operate industrial shops for many years. The Nautilus low head designs are intended to operate in open flumes and tap this energy source to power homes and small businesses. Most low head mill sites started with water wheels and changed to water turbines as more power and higher shaft speeds were required to drive modern machinery and generators. These turbines were installed with vertical power shafts to get equipment above flood levels in open flumes beneath the mill (see drawing below). In cases where only the weir remains, simple open flumes can be built from poured concrete or large plastic or steel tubes. Nautilus offers three Francis Turbine options to meet different flow and power requirements. These designs are supplied in both regulated and unregulated configurations. These turbines are typically installed in open flumes with a head range from 1 meter to a maximum of 3.7 meters, in power ranges from a few hundred watts to 3000 watts.

Type 660

The 660 is a 150 mm diameter Francis turbine with a bronze runner and a bronze and stainless steel guide vane and gate assembly. It uses water lubricated rubber bearings below water and heavy duty spherical roller bearings above water to support the shaft and pulley assembly. The turbine case is fitted with an adjustable cylinder gate to turn the unit off and regulate flow. In the lowest head version, where the pit can be easily drained, this cylinder gate can be eliminated to reduce cost. The power range of the Type 660 in an open flume is from 300 watts to 1200 watts

Nautilus - History

Nautilus Turbines are designed and built in America to operate on heads from 1 meter to 20 meters and develop up to 20 kW. Nautilus built its first regulated propeller turbine in 1981. All of the designs are based on turbines formerly manufactured for the hydroelectric industry and reduced in size for home and commercial applications. The most economical Nautilus designs are suitable for on-off operation without part flow regulation. These turbines can be applied where an excess of flow is available or installed in pairs to be turned on and off to match available flow. The regulated designs can be supplied with electrical controls to track available water supply and automatically turn the unit on and off to maintain pond levels or minimum stream flow. This reduces environmental impact and optimizes production by increasing turbine efficiency.

Guide Vanes

Runner in Guide Vanes

Exploded Diagram