The Tideflex Mixing System (TMS) for potable water storage tanks from Tideflex Technologies, a division of Red Valve Company, is a combination of Tideflex check valve technology and a multiport piping manifold. The system, which can be installed in new or existing water storage tanks of all shapes and sizes, separates the inlet and outlet and achieves complete mixing, thereby eliminating short-circuiting and water quality problems, including loss of residual, bacterial growth, nitrification and DBP (disinfection byproduct) spikes.

“Storage tanks need to have volume turnover [fluctuation of water level] in order to minimize water age,” says Mike Duer, P.E., chief engineer at Tideflex. “There is already an energy source to mix the tank when it fills, but the problem is tanks with a single fixed-diameter inlet pipe often do not mix, so the tank short-circuits, stratifies and water quality degrades.”

Short-circuiting occurs when a tank is not mixed — the water that was just put into the tank is the first water drawn from the tank, which leaves dead zones that are pockets of continually aging water.

Tideflex’s passive, no-maintenance mixing system requires no outside energy source. During the fill cycle, pressure from the distribution system closes the outlet, forcing water from the supply line through the multiple variable orifice Tideflex jet-action inlet nozzles. During the draw cycle, distribution pressure drops below the tank head, closing the inlet nozzles and opening the Waterflex outlet valves, allowing water to be drawn into the manifold pipe and out the distribution system. The passive TMS also can be turned into an active TMS using a small recirculation pump, but rarely is active mixing needed with a properly designed passive TMS.

The Tideflex nozzles progressively open and close as flow increases and decreases. At lower flows, the effective diameter of the Tideflex decreases, maximizing jet velocity — similar to placing your thumb over the end of a garden hose. The efficiency of multiple inlet ports and the optimized jet velocity of the Tideflex nozzles produce rapid mixing and improved water quality.

The TMS is extensively CFD (computational fluid dynamics) modeled, scale modeled and has been field validated to improve water quality in tanks from 10,000 to 150 million gallons. The TMS is custom-designed for every tank and a mixing analysis and water age analysis are included with each design so the utility knows how much turnover is required to achieve complete mixing.

“Long story short, the TMS achieves complete mixing, improves water quality and does not require maintenance,” Duer says. 412/279-0044; www.redvalve.com.