Evans Water Engineers

EVANS ENGINEERING

TRECARRELL MILL · TREBULLETT · LAUNCESTON · CORNWALL · UK · PL15 9QE
+44 1566 782285 · www.evans-engineering.co.uk · email sales@evans-engineering.co.uk

Water Controls and Actuators

 

OPEN CHANNEL

The range sluice gates developed for hydroelectric and water control applications, includes the lifting blade type, sector gates and weir crest gates. All are manufactured in stainless steel and cost less than conventional galvanised mild steel gates. Simplicity of construction, installation and operation has been the key design criteria. The frequency of operation, aesthetics and access are all taken into consideration at the design stage. Avoiding damage from high flood levels and floating trees may be important.

Applications include main intake sluices for waterpower and treatment works and the control of flood water levels. Industrial applications including wastewater treatment and mining slurry control also require simple corrosion proof equipment. Fish farming, leisure complexes and old mill restorations also use this type of equipment. The larger weir crest gates for controlling upstream water levels are designed for each application, taking into account the existing structures, access to the site and method of control.

Lifting blade gates as used in traditional millraces are folded up from sheet stainless steel and consist of a frame, blade and lifting mechanism. They are simple and robust but for larger gates the height of the frame above ground level can be a visual intrusion

Sector gates can have many configurations with the axis of rotation up or downstream or like a canal lock gate with the axis running vertically. They require less power to operate but are more complex and expensive.

Weir crest gates are gaining popularity for very low head hydro projects and for increasing the storage capacity of reservoirs without running the danger of flooding when the flows are high.

 

VALVES

High-pressure control applications require a spear type valve, as used in our range of impulse turbines. These can be used to give complete flow control without cavitation, and with pressure differentials in excess of 25 Bar.

Low-pressure valves of the butterfly type in cast aluminum for diameters to 1000mm, and pressures to 1 Bar.

Air operated liner valves for slurry and contaminated water up to 500mm diameter and 1 bar pressure.

We have developed water hydraulic actuation systems as a means of operating valves and sluices with a fail-safe automatic shutdown capability. All electric actuators require a battery backup, hydraulic systems have the potential to pollute the water if a pipe bursts and pneumatic systems can result in water hammer unless damped. Using modified stainless steel cylinders we have developed a simple and cost effective system that can be operated from any electrical or mechanical power source. It is pollution free and not affected by damp, in fact we install some of the units totally submerged. There are many industrial and mining activities where this type of system has potential applications.

Rupert Armstrong Evans

Managing Director