bar screen

Rake screens can be installed at sewer pumping stations and at headworks of wastewater treatment plants.

Rake screens are intended for extraction of large and medium waste solids from industrial and municipal wastewater with subsequent unloading on a transporter or into a waste bin.

The screens are intended for use in the wastewater with pH = 6.5÷8.5.

Detail
Rake screens of different dimensions are made of stainless steel AISI 304 or AISI 316 on demand. Dimensions of the rake screens are selected depending on required flow rate, wastewater composition and dimensions of channels.

The rake screen is a filtering mesh collected of bars installed into the frame. The bars made from structural shapes have tear-drop shape of cross-section that improves hydraulic characteristics of the filtering mesh. Also screen’s filtering mesh can be made of rectangular profile bars.

Bar spacing between bars of filtering mash can vary in the range of 5 - 70 mm. Rectangular frame consists of two longitudinal boards connected by cross beams. The laminated chains made of stainless steel are movable along polymeric guide ways installed on the longitudinal boards of the screen. Chain tension can be adjusted.

Cross rakes are fastened on the chains for cleaning of the filtering mesh. Chains and rakes fastened to them are actuated by shaft rotation with drive sprockets located in the screen top part. The shaft is driven by geared motor.

At the screen bottom the chain is moved along pilot slider made of abrasion-proof polymer material. Thereby revolving parts are absent at a submerged screen part. The screen is installed onto the special prop fastened in the channel and the screen can be lifted over the channel for its maintenance.
Rake screen retains and removes large and medium solids from wastewater. The solids are taken off periodically from the filtering mesh by the rake moving them to the top edge of the frame. Then the solids are taken off from the rake by means of kicker and moved along the gravity slide onto transporter or into waste bin. Screen's operation periodicity depends on equipment automation scheme.
  • mechanic and hydraulic overloads resistance: has a high-tensile design in comparison with another types of mechanized screens
  • high hydraulic efficiency is achieved using tear-shaped bars that cause the pressure gradient before screen and inside the bar spacing
  • “tear-shaped” profile protects the screen from waste jamming inside the filtering mesh. Using this design such hindrances can be removed by rakes
  • increased reliability caused by the absence of the rotating parts in the submersible part
  • submersible parts like casing, bars, chains, rakes, coating are made of stainless steel AISI 304 in order to improve corrosion resistance in aggressive environment like wastewater
  • improved ergonomics: maintainability of the screen due to accessibility of the main units in operation and possibility of its lifting up from the channel without demounting.
Different ways to automate screen's operation are possible
  • by the time period
  • by wastewater level difference in a channel upstream and downstream of the screen
  • by the customized program.
Alarm systems of the normal operation indication, the emergency turn off, the wastewater top level in the channel and others are provided.

On customer's demand there is a possibility of transferring equipment status data to automated process control system of the higher level. The screen is supplied with safety device jet lever to avoid damages of the screen like chain stretching and breaking.

The safety device actuates and stops the screen operation when the rake jams or other mechanical damages blocks free chain movement. Light and audio alarms turn on simultaneously with safety device actuates. The screens together with conveyor, compacting press and slide gates are included in a high-performance complex for mechanical wastewater treatment.

Equipping the control system with programmable modules makes it possible to unite complex into one system with common control center and to connect it with remote dispatching.
Parameters Units of measure ment Value
Filtering mesh bar spacing mm 5,8,15,20,40,50,70
Inclination angle degree 80
Electric drive pcs 1
Power kW 0,97;0,75
RKE SCREEN MODEL RANGE Screens dedicated for channel depth more than 1300mm
Dimension Channel sizes(mm) Screen dimension(mm) Drive power(kW)
width depth K B H L R kW
XX12 750-1000 1300-1600 700-900 600-800 2141 2965 2394 0.75
XX15 950-1450 1600-1800 900-1300 800-1200 2438 3265 2687
XX18 950-2100 1800-2200 900-2000 800-1900 2732 3265 2980
XX21 1150-2100 2200-2500 1100-2000 1000-1900 3028 3865 3278
XX24 1750-2100 2500-2800 1600-2000 1500-1900 3330 4165 3580
XX27 1850-2100 2800-3100 1700-2000 1600-1900 3618 4465 3870
XX30 1900-2100 3000-3400 1800-2000 1700-1900 3914 4756 4170
Screens dedicated for channel depth less than 1300mm
Dimension PChannel sizes(mm) Screen dimension(mm) Drive power(kW)
width depth K B H L R kW
XX06 600-700 800 500-600 400-500 1351 1990 1473 0.37
XX07 600-700 1000 500-600 400-500 1648 2310 1780
XX09 600-700 1000-1300 500-900 400-500 1910 2600 2026

* XX is a width in meters minus 0.1m Screens weight is specified before placing an order. It depends on screens dimension, filtering bars profile type and spacing between bars.

RKE SCREENS MAXIMUM FLOW RATE(m3/h)
Parameters Units of measure ment Value
Filtering mesh bar spacing mm 5,8,15,20,40,50,70
Lnclination angle degree 80
Electric drive pcs 1
Power kW 0,37;0,75