The Heliscreen^® is a compact powered CSO screening system with the ability to operate under surcharged conditions. With low headloss and a small footprint, the Heliscreen^® is ideal for retrofit installations with hydraulic or physical site constraints.

Applications

• New CSO facilities
• CSO retrofits
• Sites constrained by hydraulic levels or chamber dimensions
• Facilities with low maintenance requirements

  

Advantages

• 100% of screenings retained on the sanitary side of overflow weir
• Operates under surcharged conditions
• Low headloss
• Compact design
• Ability to handle high concentrations of screenings down to 6mm in diameter
• Self-cleansing
• Easy to install and maintain

Water flows into the chamber (red arrow) and begins to flow through the Heliscreen^® unit’s semi-cylindrical stainless steel perforated screen.

Water levels in the chamber rise, initiating the rotation of a helical brush mechanism on the influent side of the screen.

The spinning helical brush scrubs solids away from the screen and into the continuation flow while the effluent is discharged to a spillway (blue arrow). The screenings and continuation flow are carried on for further treatment (brown arrow).

As the water level continues to rise, spill flow and continuation flow pipes become surcharged. Excess flows are bypassed over the back plate/emergency overflow weir. Unlike most CSO screens, the powered motor of the Heliscreen^® sits above the back plate to ensure that the device will continue to operate even in the event of surcharges.

Heliscreen^® Process Overview

What is the Heliscreen^®?

The Heliscreen^® is an automatic self-cleaning powered screening system for the screening of material >6 mm in two directions. Each Heliscreen^® uses a 6mm stainless steel perforated screen foil which allows excess storm flow to discharge to an alternative water course (or storage) while ensuring that the screenings are retained within the chamber / sewer system. The Heliscreen^® is continually flushed clean to ensure the foil does not blind and that the flow is discharged freely.

What advantages does the Heliscreen^® offer?

The Heliscreen^® is normally cantilevered from the weir wall within CSO chambers. As the Heliscreen^® retains solids in the foul flow (to treatment) the Heliscreen can continue to operate even when the continuation pipe and / or spill flow pipes are completely surcharged. Also, as the screen overhangs the main through flow channel any required maintenance can be undertaken from the dry side of the weir.

What is the maximum loading rate for the Heliscreen^®?

Following independent testing of the Heliscreen^® the maximum recommended loading rate for the Heliscreen is 350 l/s/m².

What are the power requirements of the Heliscreen^®?

The Heliscreen^® requires 380-415v 3-phase supply. A single-phase motor can be provided on request. All diameters up to 11.5 ft in length use a 0.75 kw motor. All diameters >11.5 ft in length use the 1.1 kw motor. The Heliscreen^® can also be powered via a Hydraulic drive if it is desirable to keep the electrical motor out of the CSO.

What is the weight of a screen panel?

The weight of the screen panels varies depending on the diameter of unit. The maximum weight of any one screen however will not exceed 55 lbs.

What is the headloss imposed by the screen?

This is dependent on the spill flow and diameter of unit. Please contact Hydro International for further information.