Mechanical bar Screen
A Mechanical Bar Screen is an automated screening system installed in the headworks of
wastewater treatment plants, pump stations, or water intake structures. It continuously
removes coarse solids from the influent stream to protect downstream processes and
equipment from clogging and damage. Unlike manual screens, mechanical screens offer
consistent, labor-free operation with higher efficiency and lower maintenance requirements.
This screen type is ideal for medium- to large-scale treatment facilities, especially where flow
rates fluctuate or continuous operation is essential.
Main Components of Mechanical Bar Screen
Screen Frame
The main structural component that supports the entire screen mechanism. Fabricated from
stainless steel or hot-dip galvanized steel, the frame is custom-sized to fit the channel width and
depth, with a typical installation angle between 60°–75°.
Screen Bars
Flat or trapezoidal bars made of carbon or stainless steel are mounted vertically across the
channel width. The spacing between the bars (screen opening) typically ranges from 10 to 50
mm, capturing medium to large solid particles.
Cleaning Mechanism (Rake or Comb)
A mechanical rake or comb, driven by a motorized system, moves along the screen bars to
remove accumulated solids. The rake is usually attached to a chain or cable system and may
include a wiper to ensure efficient discharge.
Drive Unit
Comprises an electric motor (IP 55 protection or higher) and a gear reducer. The drive unit
powers the cleaning mechanism, ensuring controlled motion and efficient operation. It is
typically mounted above the channel and connected to the rake mechanism via shafts or chains.
Chain or Cable System
Endless chains or steel cables guide the rake along the screen bars. These components are
designed to operate under high loads and are often made of stainless steel for corrosion
resistance.
Discharge Chute
A sloped metal chute positioned at the top of the screen to direct screenings into a conveyor,
container, or compactor. It is welded or bolted to the screen frame.
Wiper Assembly (Optional)
A polyethylene (PE) or stainless-steel wiper can be installed to clean the rake before it
discharges the collected debris.
Standard Features
• Continuous automatic operation
• Corrosion-resistant construction
• Low energy consumption
• Compact design for retrofit or new installations
• Safe and easy maintenance access
Optional Accessories
• Ultrasonic level sensor for automatic start/stop based on water level differential
• Torque limiter for motor protection
• Local control panel with timer or level-based operation
• Emergency manual override
• Heating elements for frost protection (outdoor applications)
• Screenings compactor or washer integrated with discharge system
Typical Applications
• Municipal wastewater treatment plants
• Industrial effluent treatment systems
• Pumping station intakes
• Surface water abstraction points
• Stormwater treatment basins
STOPLOGS
Stoplogs are removable barriers used to isolate flow in open channels or tanks for maintenance,
inspection, or emergency shutdown purposes in wastewater treatment plants, pumping
stations, and water intake structures. They are manually or mechanically inserted into guide
channels embedded in concrete or steel walls, creating a watertight seal to block or control
water flow.
Stoplogs are a simple, cost-effective alternative to slide gates when infrequent isolation is
required, and they provide operational flexibility without the need for permanent or motorized
actuators
Main Components of Stoplogs
Stoplog Beams
Each stoplog beam is a horizontal barrier made of stainless steel, aluminum, or high-strength
coated carbon steel. Beams are typically hollow for ease of handling and to reduce weight while
maintaining structural rigidity. Their cross-section may be rectangular or trapezoidal, depending
on sealing and deflection requirements.
Material options:
o Stainless steel (AISI 304 / 316)
o Marine-grade aluminum (EN AW 6063-T6)
o Epoxy-coated carbon steel.
Side Guides
Side guides are vertical channels fixed to the concrete walls of the channel or tank. These
guides ensure proper alignment of the stoplogs and form the sealing interface on both sides.
They are typically fabricated from stainless steel or galvanized steel and may be embedded
during civil works or surface-mounted.
Bottom Seal Plate / Sill Beam
A bottom sill plate or seal bar is installed at the base of the opening, providing a sealing surface
for the lowest stoplog. It is designed to ensure watertightness at the bottom interface and may
include a replaceable rubber seal or neoprene gasket.
Sealing System
Stoplogs are equipped with EPDM or neoprene rubber gaskets on the bottom and side edges to
ensure tight sealing under low to moderate hydraulic pressure. The seals are replaceable and
resistant to chemicals and UV degradation.
Lifting Device (Optional)
For ease of installation and removal, a manual or crane-operated lifting beam can be supplied.
It typically includes a quick-lock mechanism or lifting eyelets compatible with standard hoisting
equipment.
Design Data
• Channel width: 300 – 5000 mm
• Stoplog height (each piece): 200 – 1500 mm
• Design head: up to 10 m water column
• Material: Stainless steel / Aluminum / Coated carbon steel
• Seal type: EPDM / Neoprene
• Installation type: Surface-mounted or embedded
• Operation: Manual or mechanical lifting
