Inlet Works

Spiral Sieve

The PWL Spiral Sieve HXS is one of the most efficient fine screen solutions for small-medium sized wastewater treatment plants, and some industrial applications.

Functional Description

Spiral Sieve HXS equipment is designed for the fine screening of wastewater. The robust and compact spiral sieves allow for screening, separation and dewatering in one system, with direct discharge into a container or the downstream conveyor unit.
The process entails liquid flow into the sieve basket, where solids with a diameter too large to penetrate the perforation are retained; thus, a layer of solids is continuously formed on the screen surface, reducing the flowthrough and causing the liquid level upstream of the screen casing to rise.
A level sensor installed upstream of the spiral measures the liquid levels, automatically activating the drive of the spiral when the pre-set maximum level is reached. This mechanism causes the solids deposits stored in the sieve basket to be transferred to the pressing zone for dewatering; after which, a rotating scraper ensures the dewatered solids are discharged. During the discharge process. the spiral brush mounted on the spiral cleans the sieve basket. The cleaning and discharge processes cause the liquid levels to drop, and when the level falls below the specified set-point, the drive automatically turns off.


• sieving, dewatering and discharge in one system
• high capture rate
• space-saving design
• hygienic wastewater sieving and dewatering
• easy maintenance
• no spray water consumption
• materials: stainless steel AISI 304 / AISI 316 Ti/L)

Technical Data

• perforation 1 to 6 mm
• wedge wire openings 0.5 to 3 mm
• installation angle up to 45°
• channel width from 250 mm up