| TECHNOLOGY


SEEING BEAUTY and ele- gance in natural patterns and processes is a fundamental human pleasure. We have an admiration for the simple and perfect way things work and an enthusiasm to capture and replicate them.


The vortex is a particular object of fascination for those of us involved in design or en- gineering, because of its sim- plicity and power. Leonardo Da Vinci once said: “Simplic- ity is the ultimate sophistica- tion.”


And simplicity can take a lot of hard work for designers to achieve. Despite its elegant principles, harnessing the power of the vortex effective- ly requires care, knowledge and expertise.


As it uses no power other than the energy of the wa- ter itself, vortex technology is inherently sustainable. It therefore feels like a very contemporary and unconven- tional solution, although in fact its use can be traced back through history.


Now the latest step-chang- es in engineering development are moving the technology on once again, particularly in the design and application of the Hydro-Brake, which through its own success has become an industry-standard term for flow controls. Because of this, specification of the cor- rect technology is therefore essential.


In the UK, vortex flow con- trol technology was first har- nessed in the mid 20th cen- tury to control and dissipate the energy of water dropping from high-level drains into deep-drop sewers. Follow- ing on from the Drop-Shaft innovations, the first Hydro- Brake Flow Controls were designed and developed in the 1970s and even featured on the BBC’s Tomorrow’s World programme in 1983, providing a glimpse of the future of sustainable drainage design. Today vortex technol- ogy is used in thousands of drainage and sewerage ap- plications all over the world. It also provides the basis for hydrodynamic separation of silts, oils and pollutants from stormwater and of solids sep- aration solutions in sewerage treatment.


Vortex flow controls are used in thousands of applica- tions worldwide in all shapes and sizes − from giant flood prevention schemes, to eve- ryday small-catchment drain- age schemes; from major flag- ship housing developments, to more prosaic applications controlling the flows out of Combined Sewer Overflows (CSOs).


In the UK, new National Standards for Sustainable Drainage Systems (SuDS) will place increased expectations for controlling the flow and quantity of surface water in


Optimised hydraulic efficiency


Vortex flow controls are used in thousands of applications worldwide in all shapes and sizes. Alex Stephenson looks at how Hydro- Brake Flow Control technology is making a difference in Sustainable Drainage Systems.


new developments. Vortex technology provides the per- fect solution – but its design and specification need careful consideration to meet the re- quired standards effectively. It is no secret that many vortex flow controls are based on Hydro-Brake technology. The name Hydro-Brake has become a generic term, rather like the Hoover to vacuum cleaners, or Biro to ballpoint pens. The specification of a Hydro-Brake or equivalent is standard practice to designers using industry-standard mod- elling software. Imitation may be a sincere form of flattery, but in the case of vortex technology substituting one product with another could lead to disaster. Whilst the technology may appear simple and elegant, the differences in engineering are significant. The choices made by designers and speci- fiers of flow controls have a huge impact on achieving ef- fective flood prevention, as well as on the installation and lifetime costs of a project.


SERVICE RESERVOIRS


WATER TOWERS


WWTW


INSPECTION, CLEANING & CHLORINATING


CORROSION PROTECTION


Storage savings achieved with Hydro-Brake Flow Control


The internal geometry of a Hydro-Brake Flow Control is designed to enable water to flow unrestricted through it for as long as possible. When the water upstream reaches a pre-determined height, for ex- ample in a flood situation, a vortex is triggered in the flow. The vortex creates a core of air in the centre, throttling back


Developments in vortex flow con- trol technology have enabled new standards in design versatility


the water, and releasing it at a measured, controlled rate. Compared


with conven-


tional technologies such as an orifice plate, penstock or slide gate valve, the flow of water out of a vortex flow control has much less energy per unit of cross- sectional area. It is therefore, much less likely to cause scouring or physical


damage to downstream struc- tures, protecting sensitive wetlands, ponds, basins or watercourses, even preventing damage to sewer infrastruc- ture. Bringing water quality back under control not only combats flooding, but also fa- cilitates effective stormwater treatment practices. The re- duction of peak flows causes less of a short-term shock pol- lutant load to the receiving waters and allows increased dilution. The 1,900-home Elvetham Heath development at Fleet is hailed as a shining exam- ple of Sustainable Drainage Systems (SUDS) using linked swales and ponds. It is the performance of 18 Hydro- Brake Flow Control devices that enables the SUDS scheme to operate successfully. A visitor to the site would not necessarily realise that the numerous swales and large ponds are interconnected. The strategically


placed Hydro-


Brake Flow Controls provide balancing and buffering of the surface water run-off. Across


STONBURY 27 YEARS AS MARKET LEADERS IN THE REFURBISHMENT OF WATER RETAINING STRUCTURES & ASSOCIATED ASSETS


Reservoir Repair & Refurb - Steel Tank Repairs & Coatings - Water Tower Refurb Sewage Tank Refurb - Pipe & Other Bridges - Corrosion Protection - Concrete Repair Inspection Reports - Cleaning & Chlorination - Security Works inc Access Covers Ladders, Handrails & Walkways - Minor Civils - EU Hygiene Training


Tel 01234 750924 email enquiries@stonbury.co.uk www.stonbury.com 8 | WET News | July 2012


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