The orifices incorporated into the design of the Trilateral underdrain are sized and arranged to accommodate the optimal air and water flow rates required to optimize your backwash sequence. Typical air flow rates range from 3-5 scfm/sf (54.54-90.9 m³/hr/m²) with backwash water rates from 15 – 22 1/2 gpm/sf (36.5-54.8 m³/hr/m²). When provided with thick porous plate, the Trilateral underdrain supports filter media directly without the need for traditional support gravel. Additionally, the Trilateral underdrain offers several unique design features to improve reliability and extend the underdrain’s life cycle.
The rigid top surface of the Trilateral Underdrain is designed to transfer surface loads directly into the side walls of each individual block. This load transfer forces the outer walls of each block into the grout, thereby strengthening the interlock between the underdrain and grout and increasing the hold down capacity of the underdrain.
Material: Virgin High Density Polyethylene (HDPE)
Weight: Approximately 4.6 pounds / square foot (22.4 kg/m²)
Standard Block Dimensions: 48″ long x 10 5/8″ wide x 12″ high (121cm long x 26.9cm wide x 30.48cm high)
Distribution Orifices: Approximately 1/4″ (.635cm) diameter with approximately 22/square foot (2 m²)
Connections: Bell & spigot with integrally molded clips and o-ring seal