Flow ControlHydro International

  • Reg-U-Flo® Vortex Valve
  • Hydro Vortex Drop Shaft

Reg-U-Flo Vortex Valve

The Reg-U-Flo® Vortex Flow Control provides superior hydraulic performance over conventional flow controls. Its unique features reduce the chance of blockages and reduce runoff detention volumes by up to 30%.

This self-activating device uses vortex principles to control and slow the runoff rate of stormwater without the need for moving parts or external power requirements.

Three series of Reg-U-Flo® Vortex Flow Controls are available to suit various applications and design constraints (the S, V, and C series).


  • Used as the outlet flow control for retention/detention systems for stormwater or combined sewers
  • A retrofit solution in Runoff Volume Reduction schemes where detention/retention ponds are retrofitted to capture more site runoff
  • Reduction of runoff volume from sites, when used as a flow control to the inlet of the drainage system
  • Green Infrastructure schemes such as "Blue Roof" stormwater detention schemes
  • Outlet flow control for structural flood control schemes such as dams


  • When used as an outlet flow control, reduces storage requirements by up to 30%
  • When used for runoff volume reduction and green infrastructure schemes, controls more flow than an equivalent orifice for greater on-site detention/retention capacities
  • Up to 50% savings in project costs
  • Self-activating with no moving parts or power requirements
  • Area of opening is 3-6 times larger than the equivalent orifice
  • Virtually maintenance free
  • Performance proven with 17,000 installations worldwide



Flow enters the volute tangentially through the inlet. Under low flow conditions, the Reg-U-Flo acts as a large orifice and water passes directly from the inlet to the outlet. As flow increases and reaches the flush flow point, high peripheral velocities start throttling action. As head increases, the valve approaches the kickback point and an air-filled core starts to form in the volute. As head continues to increase, the air core fully stabilizes and the valve discharge is throttled to that of a smaller orifice.


The Reg-U-Flo® Vortex Valve out-performs conventional flow control devices. Its unique S-shaped head/discharge curve, which has been devised from extensive systematic modelling and field testing, comprises two distinct phases. As the head increases, a transition takes place from free flow to vortex controlled flow . The Reg-U-Flo® Vortex Valve thereby achieves maximum design discharge rates at lower heads than conventional controls. As a result, storage requirements are reduced by up to 30%, significantly reducing project capital costs.

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Hydro International: Reg-U-Flo Hydro International: Reg-U-Flo (985 KB)


Hydro Vortex Drop Shaft

The Hydro Vortex Drop™ Shaft is a compact, single shaft system used for controlling flows from high level sewers into deep tunnels. The system dissipates the energy of dropping water in order to protect infrastructure from noise, vibration and damage.


  • Controlled drop of sewer flows into deep tunnels
  • Energy dissipation of dropping water
  • Flood control
  • Combined sewer systems
  • Stormwater systems


  • No auxiliary air and/or maintenance shafts needed
  • No requirement to keep an air core within the drop pipes so pipe sizes are significantly reduced
  • Safe, controlled, efficient
  • Self-activating with no moving parts
  • A multiple pipe arrangement can accommodate higher flow rates




Vortex Mode

During low flow conditions, when the Hydro Vortex Drop™ Shaft is operating in the air-entrained mode, water flows into the inlet of the vertical drop barrel. Air enters the vertical pipe through the open air switch, located at a higher elevation than the inlet pipe. Water flows down through the vertical pipe barrel and into the cylindrically shaped Energy Dissipation Unit (EDU), where the geometry of the device causes water to flow in a horizontal vortex flow path through the cylinder and out to the outlet. The air core at the center of the vortex in the EDU throttles back and dissipates the energy of the flow that is conveyed down the vertical drop pipe.


Pipe Full Mode

The combination of the vertical pipe and vortex in the EDU continues to throttle the effluent discharge as flows into the upstream chamber increase. As a result, the water level in the upstream chamber rises. As water levels rise, the Air Switch controls the amount of air that is allowed into the Vertical Drop Pipe. When the water level finally reaches the height of the Air Switch the air is switched off and the flow in the vertical drop pipe transitions into a pipe full mode of operation. The design of the air switch ensures a smooth transition preventing glugging noises and vibrations that can be caused by other drop shaft systems.



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Hydro International: Hydro Vortex Drop™ Shaft Hydro International: Hydro Vortex Drop™ Shaft (122 KB)