Bar Screen

Bar screens are the most important type of screening equipment. They are most commonly used at the headworks of the water treatment plants. They are used to protect the plant against the entrance of large objects that can probably create blockage in various sections of the installation. They separate and extract easily bulky matter found in the raw influent likely to intervene with later operation. They separate large solid objects, rags and other debris that can create clog & jams in pipes, pumps or other downstream equipment at pump stations.

Bar screens are made of steel bars with openings depending upon the requirement of the processing. Usually they consist of a set of evenly spaced steel bars mounted vertically in the influent channel. It is attached with a mechanically or hydraulically actuated rake mechanism, which periodically removes the junk from the front of bars. They play a very important role in determining the overall plant performance.

Bar screens are mainly of two types depending upon its movement. One is removable type and other is fixed type. The removable type bar screens are operated by means of guides installed on the side walls of the concrete structure. A lifting beam is used to raise/lower the bar screen. The segments are manually cleaned after raising it to the operating floor. The fixed type bar screens are installed on the concrete structure by bolting or grouting. They are cleaned by a bar screen cleaning equipment.

Types of Bar Screen

• Chain Operated Bar Screen
• Cable Operated Bar Screen
• Cantenary Bar Screen
• Double Guard Bar Screen

Chain Operated Bar Screen
The chain operated bar screen is comprised of a rake assembly which slides on properly sized drives. The rake is driven from two ends through long chains which in-turn is carried on two different sets of sprockets on headshaft and footshaft.


Cable Operated Bar Screen
The cable operated bar screen is mainly comprise of a rake assembly. It remain engaged on both ends of the channel through sliding blocks or rollers. The rake assembly is driven by the number of sets of cables depending upon the width of the Screens.

Cantenary/ Catenary Bar Screen
Cantenary bar screens are similar to the chain operated bar screen. The only difference is that there are no submerged sprockets and instead open guides. They are provided for smooth movement under the wastewater to ensure smooth ride over large debris.

Double Guard Bar Screen
Double guard bar screens are similar to the chain operated bar screen. The difference is that they have double rack so offset and spaced. As the wastewater flows from upstream to downstream across the rack, it flows first through the wider bar spacing and then to the finer bar spacing.