Decision Matrix
The client for this project stated the following priorities for the bar screen design:
Pass small debris through the bar screen.
Push larger debris up onto the street.
Maintain flow efficiency as best as possible within the channel.
Using this information, a design matrix was created, shown on the right.
Flume Design and Construction
Side View of Flume Modela
Constructed Flume
Photo by Maddison Klingberg
To test different bar screen designs, a flume was constructed using 5/16" plywood sheets, 2" x 4" planks of wood, and polyurethane to make the wood water-resistant.a
Cross-Sectional View of Flume Model
Design Alternatives
Combinations of 3 bar screen angles, 4 bar frame designs, and 4 mesh screen sizes were used to determine the best bar screen option for the City of Flagstaff. This resulted with 48 different designs being tested. The bar frames were designed with SolidWorks and printed at each angle using an FDM 3D printer with PLA plastic. The mesh screens were then attached to each printed design using 0.22-gauge wire. Photos and descriptions of each component are provided below. The SolidWorks drawings for each design are provided on the Documents page.
Team Working on Designs
Photo by Diego Medina
Bar Screen Angles
Bar Frames
Flat Screen
Photo by Samuel Turner
Flat Point
Photo by Samuel Turner
Curved
Photo by Samuel Turner
Arrowhead
Photo by Samuel Turner
Bar Screens
#4 Mesh
Model Wire Diameter - 0.047 in.
Model Opening - 0.203 in.
Real Bar Diameter - 2.25 in.
Real Screen Opening - 9.72 in.
Photo by Samuel Turner
#5 Mesh
Model Wire Diameter - 0.041 in.
Model Opening - 0.159 in.
Real Bar Diameter - 1.96 in.
Real Screen Opening - 7.61 in.
Photo by Samuel Turner
#8 Mesh
Model Wire Diameter - 0.028 in.
Model Opening - 0.097 in.
Real Bar Diameter - 1.34 in.
Real Screen Opening - 4.64 in.
Photo by Samuel Turner
#10 Mesh
Model Wire Diameter - 0.025 in.
Model Opening - 0.075 in.
Real Bar Diameter - 1.20 in.
Real Screen Opening - 3.59 in.
Photo by Samuel Turner
Debris Selection
To simulate different debris in testing, six different items were selected and used due to their small size fitting the necessary scaled measurements for tests.
Broom Bristles
(Pine Needles)
Photo by Samuel Turner
Calendula Flowers
(Brush/Shrubs)
Photo by Samuel Turner
Wooden Dowels
(Tree Branches/Trunks)
Photo by Samuel Turner
Model Moss
(Vegetation)
Photo by Samuel Turner
Cut Feathers
(Branches/Clumping Material)
Photo by Samuel Turner
Plastic Leaves
(Inorganic Matter)
Photo by Samuel Turner