Frequently Asked Questions
Q. What is the Heliscreen® ?
A. 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
brushed clean to ensure the foil does not blind and that
the flow is discharged freely.
Q. What advantages does the Heliscreen® offer?
A. 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.
Q. What is the maximum loading rate for the Heliscreen® ?
A. Following independent testing of the Heliscreen at the
national CSO testing facility at Wigan and Knostrop Wastewater
Treatment Works, the maximum recommended loading rate for
the Heliscreen is 350 l/s/m2 .
Q. What are the power requirements of the Heliscreen® ?
A. The Heliscreen requires 380-415v 3-phase supply. A single-phase
motor can be provided on request. All diameters up to 3.5 m
in length use a 0.75 kw motor. All diameters >3.5 m
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.
Q What Heliscreen® sizes are available?
A. The diameters of Heliscreen® available are 300,
500, 700 and 1000 mm.
The effective lengths of screens range from 1.5 m to 7 m in 0.5 m increments
up to 4.0 m then 1 m increments up to 7 m.
When considering a particular spill flow, more than one Heliscreen® may
be available for selection. The engineer can decide which
to opt for by considering the weir length required.
Q. What is the weight of a screen panel?
A. The weight of the screen panels varies depending on the
diameter of unit. The maximum weight of any one screen however
will not exceed 25 kg.
Q. What is the head loss imposed by the screen?
A. This is dependant on the spill flow and diameter of unit.
Please contact Hydro International for further information. |
