JEC COMPOSITES MAGAZINE - Issue #79 - March 2013 - 111

Tab. 1: Characteristics of Polistok pipe filters

Unit size

STF
50

STF
80

STF
100

STF
130

STF
150

STF
200

STF
230

STF
300

STF
440

Internal diameter, mm

100

125

142

174

210

267

416

Length of one module, m

0.5 to 3.4

Type of pipe filter connection

Bell-spigot, socket-coupled, flanged, threaded

Cell size of the filtering web, mm

0,1’ x 0,2 to 1,0’ x 2.0’’

Working temperature, °C

−60 to +60

Filtration index, m/day

300 to 1,500

enough to protect the filtering layer
from deformations (especially stripping) related to casing manipulations.
This type of GRP radial drainage
filter could be particularly suitable for
construction works in the tight sites
typical of modern cities.
Fig. 5: Toroidal type STF-80 air-dispersing element
used to supply air pressure to a wastewater
biochemical purification reactor (source: Polistok)

Fig. 6: Hybrid PVC-GRP well filter design produced
by Polistok (source: Polistok)

operating experience. Originally, they
were used in water supply (freshwater
wells) and wastewater systems as a
drainage-distributing system for highspeed filters, and in drainage systems
at sludge sites. Later on, they were
also used in hydro-energy construction, and in case of landslide hazards.
Current applications for bundlewound GRP pipe filters also include
horizontal and radial drainage systems,
well points in vacuum water drawdown
installations, direct river water intakes,
clearing filters for waste and technological water, and ventilation drainage systems. One of Polistok’s latest
developments is a GRP filter for radial
drainage wells that is strong and elastic

Others players
Similar bundle-wound GRP pipe filter
designs are available from Potok-M, a
company of the MashSpezStroy group,
and from the Vozrozhdenie group of
companies (“Renaissance” in English),
both based in Perm city, Russia.
This type of bundle-wound GRP pipe
filters is expected to position better
in moveable soils than drainage pipes
made by perforation of more rigid
pipes, like centrifugally cast GRP
pipes (Hobas-type) or continuously
wound GRP pipes with a sand-containing structural layer (Amiantit type).
The Uralstavan-Engineering company
(Yekaterinburg, Russia), a member
of the Vozrozhdenie Group, has been
producing bundle-wound porous

Fig. 7: Pipe filters produced by Potok-M

No79 March 2013

Fig. 8: Pipe filters for sewage treatment systems.
Material: glass fibre, internal diameter: 80-300
mm, max. length: 9 m, max. operating temperature: +90°C, max. working pressure: 1 MPa (10
atm), type of pipe connection: plugs

GRP pipe aerators since 1995. Since
then, despite the lack of any technical
service or maintenance, these aerators have not been affected by mud
clogging and have kept their original
hydro-dynamic properties. When
clogging of the small drilled openings
in steel pipes is unavoidable (and this
requires unloading and cleaning, or
even exchange of the air tanks every
5 years on average), Uralstavan-Engineering emphasizes a unique property of GRP to prevent the growth
of microorganisms, as is confirmed
by prolonged practical operation. So
GRP makes it possible to create small
(3 mm diameter) openings to form
small air bubbles and provide a higher
aeration speed.
Because the efficiency of the aeration
system will determine the energy
consumption of the waste-water system, the absence of clogging (which
finally results in complete occlusion
of the aerator) provides substantial
savings (up to 40%) in municipal

/ jec composites magazine 111

JEC COMPOSITES MAGAZINE - Issue #79 - March 2013

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