Frequently Asked Questions
Q. What is a Hydro-Static® Screen?
A. The Hydro-Static® Screen is a self-activating,
non-powered screening system for the removal of material >6 mm
in two directions. The screen is designed to intercept and
retain aesthetically offensive material and gross solids
at all states of flow up to the peak storm flow, with the
material remaining in the foul sewer during and after the
storm event. The screen can be configured as an up flow
Screen or a weir-mounted through flow screen.
Q. What advantages does the Hydro-Static® Screen offer?
A. Patented flow modifying baffles are used on the up flow
Hydro-Static® Screen to encourage a re-circulation pattern
above and below the screen panels. This flow pattern helps
reduce any blinding effect when the screen is in operation.
The up flow Hydro-Static® Screen is also configured
so that the top of the corrugated screen sits below the weir
level. Once a storm has subsided this will allow a volume
of water to backwash the screen panels helping to remove
any debris that may be caught on the underside of the screen.
The through flow Hydro-Static® Screen is offset from
the vertical to encourage screening to drop away from the
corrugated mesh one the storm has subsided.
Q. Is the Hydro-Static® Screen manufactured in standard
sizes?
A. Whilst we try to encourage the use of standard screen
panels (1.215 x 0.641 m in plan) we can design
Hydro-Static® Screens specific to each application.
We are usually able to offer a bespoke solution by cutting/extending
our screen panels to suit without any increase in cost. This
can be particularly useful for retrofit solutions.
Q. What are the loading rates/head loss figures for the
Hydro-Static® Screen?
A. The Hydro-Static® Screen has undergone
independent testing at the national CSO testing facility
at Wigan Wastewater Treatment Works. Following on from this
testing the recommended design loading range for the Hydro-Static® Screen
is 50-100 l/s/m2 (nominal value = 75 l/s/m2 ).
Head Loss figures for a 50% blinded screen at various loading
rates are as follows:
Loading
Rate (l/s/m2 ) |
Head Loss
(mm) |
100 |
100 |
75 |
55 |
50 |
40 |
Q. What is the weight of a screen panel?
A. The weight of a standard panel (1.215 x 0.641 m)
is 20 kg. This equates to 25.64 kg/m2 of plan area
and this value should be applied to non-standard panels.
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