Screening Equipment

The screen is typically installed in a pumping station or at the inlet of sewage or water treatment plants. The retained solids are then extracted by means of a cable driven manual raking system which lifts the solids outside the channel and discharges into a hopper.

To prevent material too coarse from reaching the travelling band screens installed downstream for finer screening, bar screens may be used in two stages where the first screen with wider bar spacing remove bulky solids; a second bar screen with smaller bar spacing then remove debris still coarse enough to clog.

Filtration at the first stage of sewage water intake system is done by Bar screens.

Bar screens can be categorized according to various properties:

1. Removable Type: Screen can be removed & replaced from Frame. Easy to clean & lesser maintenance.

2. Fixed Type: Screen is fixed to the channel or opening. This cannot be removed.

Manual Screens
Static Screens are known for Low installation and operating cost & High capacity per unit area of screen.

1. Curved/ Hyperbolic Fine screen

2. Flat Fine Screen

3. Fine Screens – Generally distance between two bars is

4. Medium Screen – Generally distance between two bars is

5. Coarse Screen – Generally distance between two bars is

6. Wedge Type Bar Screen

7. Straight/ Flat type Bar screen

Mechanical screen with rakes of bar vertical way and linear in motion. They are installed in the wastewater channel with angle of 70 - 75°. The equipment consists of screen, motorreducer, base frame, chain mechanism, rake and rake cleaning system. The motion is conveyed to the rakes with the help of the chain mechanism. Number of the rakes depends on to the depth of channel and in the consequence of the length of the screen.

The smooth running, endless track system employs a geardriven cleaning rake to carry screenings from the submerged bar rack to a discharge chute for removal – without the use of chains, sprockets, cables or any underwater moving parts.

Applications- STP headwork: protect downstream equipment, Pumping stations; flood control; Water intake for remove large debris; Ideal for both municipal and industrial use.

Benefits: Above water operation, No submerged moving parts; Flexible & customized design, Heavy duty, wide range, Positive screening discharge.

The step screen consists of a series of stationary and mobile steps alternating with each other. As the effluent flows through the step screen, a screening mat develops along the surface of the screen. The mobile steps progressively lift the mat of solids along the inclination of the screen. On reaching the top of the step screen, the solids are discharged by gravity into a screw conveyor or similar device.

The low-inclination angle ensures that a screening mat is retained continuously during the entire operation and prevents the roll down encountered in steeper screens.

A consistent screening mat contributes to a uniform and high solids capture rate.

Step screen is capable of handling flows of up to 23,775 gpm / 5,400 m³/hr through a single unit.

Applications: municipal waste water treatment plants, industrial waste water treatment plants such as: paper mill, slaughterhouses, food industry, fish industry, chemical industry.

Advantages: separation of non-biodegradable solids, floating or inorganic substances, self-cleaning screen, low operating costs, available also in stainless steel tank, with nozzles.