- Bar spacing available from ½” to 12″
- Easy retrofit into existing civil works
- Commonly fabricated of galvanized carbon steel or stainless steel, but other materials are available
Bar screens can be designed to fit within guides or StopGates™ embedded into the concrete, or onto channel-mounted beams. They can be used on a temporary basis, typically in conditions where debris levels are low but protection is still required, or as a permanent installation. Bar screens are designed to withstand a variety of differential heads and the bars can be arranged with spaces of 10mm (½”) up to 300mm (12”) to accommodate any size or type of debris. A range of differing raking solutions can be provided for occasional, fully automatic or manual cleaning.
- Flexible design to suit particular applications
- Durable materials protect against corrosion
- Vertical storage simplifies handling
Your First Line of Defense
There are two main types of bar screens:
- Fixed – the screen supporting structure is rigidly attached to the civil works, requiring dewatering of the screen chamber for removal.
- Removable – the bar screen is constructed as a self-contained unit that includes the screening bars and their supporting frame. This screen can be removed from a flooded screening channel by using a suitable lifting attachment. Removable bar screens are commonly located in the StopGate™ guides at the entry to water intakes and are not suited to automated cleaning
Bar screens can be mechanically cleaned by one of a number of different raking type machines, or cleaned by hand using a rake, or by lifting and backwashing. The choice of cleaning method will depend on consideration of the following:
- Screen and channel size
- Debris quantity type
- Reliability and redundancy requirements
- Degree of automation required
- Bar screen aperture size.
The type and size of the cleaning device is based on the physical size of bar screen, bar spacing, number of bar screens (in the case of a traversing raking screen), and any known risk of larger influxes of particular debris types e.g. jellyfish, kelp, sea grass.
For modern civil work intakes, the principle types of raking machine used are:
- Fixed head cable-hauled raking machine
- Traversing cable-hauled raking machine
- Bosker® raked bar screen
- Continuous chain raked bar screen (CCRB)
To determine bar screen size, the following data are required:
- Maximum design flow
- Minimum depth of water at design flow
- Bar spacing
- Any limits on channel dimensions
- Any customer specified limits on design velocity or headloss