The Hydro-Brake® Optimum vortex flow control provides customized water quantity management for surface, foul or combined water across a wide range of flows and for a variety of applications.

Self-activated and precision engineered to meet each site or network's specific flow, head and storage requirements, the Hydro-Brake® Optimum delivers effective protection from upstream and downstream flooding as part of a sustainable or low-impact drainage system.

With no moving parts and no power requirements, the Hydro-Brake® Optimum provides reliable, low-maintenance, engineered flood management as part of green infrastructure developments.

Independently assessed, approved and certified

The Hydro-Brake® Optimum has been independently assessed, approved and certified by both the BBA (Certification no. 08/4596) and the WRc (Certification no. PT/409/0417).

BBA & WRc Logos - Hydro-Brake Optimum

Only Hydro-Brake® Optimum:

  • Is individually custom-designed to meet specific site and network requirements
  • Draws on a legacy of more than 30 years of vortex flow control technology
  • Is designed and delivered by the leaders in flow control 

The Hydro-Brake® Optimum flow control was formerly marketed as the Reg-U-Flo® vortex valve.

Designed for

High flow
Low flow
Medium flow


Get custom-designed, precision-engineered flood protection

Every Hydro-Brake® Optimum is individually designed, sized and precision engineered to meet the specific requirements of the site, network and environment in which it is installed, enabling engineers to deliver tailored protection against upstream and downstream flooding. Specify LID, SuDS and green infrastructure projects with built-in protection against storm events, management of everyday surface water runoff and capacity for the future effects of climate change.

Deliver small, medium or large-scale low-impact drainage

With a maximum flow of up to 8,700 gpm the Hydro-Brake® Optimum provides effective, reliable flow control across a wide range of environments and applications, from small individual plots to large sewer networks, giving designers the flexibility to implement a range of sustainable, low-impact drainage and green infrastructure projects.

Design with complete freedom

The Hydro-Brake® Optimum provides complete freedom in the response characteristic of the flow control. For a given maximum design head and flow, the point at which the vortex begins can be specified, enabling engineers to customize flow controls to solve even the most challenging requirements.

Independently assessed, approved and certified

Having been independently evaluated, tested, approved and certified by the UK BBA (Certification no. 08/4596) and the WRc (Certification no. PT/329/0412), customers can be confident that every flow control neets rigorous quality, performance and installation standards.

How it works

How it works

Hydro-Brake® Optimum flow controls are self-activating, relying on upstream hydraulic head to generate an air-filled vortex within the centre of the casing. The flow control moves through three distinct phases of operation:

Low Flow

Under low flow conditions the flow control behaves like an oversized orifice. The flow is gentle, with minimal turbulence inside the volute of the flow control or the outlet pipe. As the water level starts to increase above the soffit of the outlet, air becomes trapped in the volute. This exerts a back pressure against the water and begins to restrict the cross-sectional area available for water flow. As the water depth continues to increase, a vortex begins to form within the unit and the entrapped air forms the central core. At first there is not enough energy in the water flow to sustain a stable vortex, so the vortex will continually start to build and collapse.

The head at the end of this phase is the point at which there is sufficient energy within the flow to sustain a stable vortex.

High Flow

A stable vortex is maintained within the flow control. High peripheral velocities around an aerated core create a back pressure, which effectively chokes the flow through the outlet aperture. Following initiation of the vortex, the flow control restricts the flow in a similar fashion to an orifice, but with clear openings up to 600% larger, significantly reducing the risk of blockage.

Drain Down

As the water level subsides, the energy within the flow reduces and the vortex collapses. Air is drawn into the volute and the flow control returns to operating in a similar manner to an oversized orifice. This drains the system quickly and more effectively, so that the flood storage reservoir is ready for the next event.

See it in action


Technical information

Technical information

Performance Characteristics

Maximum flow: 8,700 gpm

Maximum head: 4.4 yds

Performance Customisation

Reduce onsite storage

Matching the Flush-Flo™ point equal to the design point means that the device will be as hydraulically efficient as possible, leading to more water passing through the unit during the earlier stages of a storm, thus reducing the amount of water that needs to be stored upstream.

Limit flow control size

Reducing the Flush-Flo™ point reduces the size of the device, so if the exact available space is known then the Flush-Flo™ point may be tuned to give the most hydraulically efficient performance within the space available. 

Design complex systems

Custom Flush-Flo™ points can be specified, enabling the design of precise 'complex flow control' arrangements where the pre-developed hydrology is aligned to the post-developed site.




Case Studies

Case Studies