A LITTLE BIT OF SCREW PRESS TECHNOLOGY.

Structure

The screw presses of the type SP consist of a robust closed housing made of stainless steel with covers, which are optionally arranged on the top or on the sides. The advantage of covers arranged on the top is that opening them does not lead to contamination of the working environment. Inside the machine there is the screen basket and the rotating screw shaft, which is driven by a NORD offset geared motor. On the screw flanks, the sealing lips are fixed with fastening screws as a seal between the screw shaft and the screen basket. To allow easy access to the screw shaft for changing the sealing lips, the screen basket is divided in the longitudinal and transverse directions.

Washing System

The screw press is equipped with a washing system for cleaning the screen basket during and after the dewatering process. The washing device comprises a washing ring with exchangeable nozzles, which, from size SP 500, is pulled along the entire longitudinal axis of the screen basket by a washing carriage with chain drive (at freely adjustable speed). The travel of the washing carriage is limited by the two built-in limit switches. In the smaller screw presses, the movement of the washing ring is effected by pneumatic cylinders.

Functional description:

The screw press was developed for dewatering municipal and industrial sludge. In order to achieve the best possible dewatering results and flocculation of the sludge, we design sludge dewatering plants with screw presses together with mixing tanks. The polymer is prepared in the polymer plant. The polymer metering pump conveys the polymer towards the mixing tank. Before entering the mixing tank, it is mixed with the thin sludge coming from the thin sludge feeding pump and together they flow into the mixing tank. There, an agitator designed as an agitator shaft with an agitator paddle ensures mixing and flocculation. Subsequently, the flocculated sludge at the top passes through the sludge inlet of the screw press into the front section of the screw shaft.

In the screen basket, the solids are separated from the filtrate as the filtrate trickles out of the screen basket’s screen holes and is collected in the filtrate trough, from where it then flows out of the machine via the filtrate drain. The solids that are larger than the screen holes remain inside the screen basket and are advanced by the rotating screw shaft. At the end of the screw shaft, the dewatered sludge is continuously ejected. At the discharge, a press cone is mounted, which presses against the sludge to be ejected by means of an air pressure cylinder via a pressure control valve. The discharge of the screw press is designed as a discharge chute as standard and, depending on the design, leads either directly into a container installed on site under the machine or into a discharge conveyor.

Advantages:

  • Safe and automatic operation
  • Low wear due to low rotational speed
  • Easy access for maintenance
  • Long service life
  • Low drive power
  • Low operating noise
  • Robust housing made of stainless steel
  • Years of experience in the field of sludge dewatering
  • Countless references at home and abroad