FOR FINISHED WATER STORAGE FACILITIESFOR FINISHED WATER STORAGE FACILITIES

Short-circuiting is most severe with common inlet/outletpipes (Figure 1) or when the inlet and outlet are in closeproximity to one another. The last water put into the tankis the first water that is drawn out (last-in, first-out).Stagnant areas develop outside this area of influence andthe water in these areas can be days or weeks old, result-ing in the loss of disinfectant residual.

Locating inlet and outlet pipes at opposite sides of thetank will mitigate short-circuiting. Prior to the TMS, thismeant installing two separate pipes and two tankpenetrations, a valve vault outside of the tank, extra isola-tion and check valves, etc. The TMS achieves inlet/outletseparation with a single manifold pipe installed inside thereservoir. Two sets of Tideflex® Check Valves located onopposite ends of the manifold function as inlets and out-lets (Figure 2). Tideflex® valves are an all-rubber/fabric matrix and have no mechanical parts. They arecompletely passive and operate solely on differentialpressure (Figure 3) so the tank fills and draws based ondistribution system and tank head without any outsideenergy source. Significant cost savings are realized com-pared to other methods of separating the inlet and outlet.

STAGNANT WATER

P

P

openwhenfilling

openwhendraining

PCommonInlet/Outlet Pipe P

Supply Pipe

Inlets

Outlets

TMSManifold Pipe

Improving Water Qualityin Distribution Reservoirs

Tideflex® Mixing System

PELIMINATE SHORT-CIRCUITING

Water quality in finished water storage facilities is oneof the most important issues facing water utilitiestoday, especially in light of recently adopted andproposed regulations. Low turnover, poor mixing andshort-circuiting within distribution storage tanks canresult in water quality problems such as:

The Tideflex® Mixing System (TMS) is a cost-effectivesolution that can be easily installed in new or existingtanks and reservoirs. The TMS eliminates short-circuiting and improves mixing thereby maintainingthe highest water quality in your tanks and reservoirs.

P Prevents short-circuiting, stagnationand "dead zones"

P Separates inlet/outlet with one manifold pipe

P Tideflex® variable orifice maximizes jet velocityfor improved mixing

P Eliminates thermal stratification

P Mitigates ice formation

P Uses existing tank penetration

P Completely passive; no external energy source

P Tideflex and Waterflex are ANSI/NSF Standard 61 Certified

P Complete system design and hydraulic sizing

• Loss of disinfectant residual

• Bacterial re-growth

• Disinfection by-product (DBP) formation

• Nitrification in chlorinated systems

• Algae and Biofilm growth

• Taste and odor complaints

Forward differential pressureprogressively opens the valve

Reverse differential pressurecloses and seals the valve

Fig. 3

Fig. 1 Fig. 2

NSF®

Patented Allowed

While separating the inlet and outlet is a drasticimprovement regarding short-circuiting, a dedicatedinlet pipe can still induce circulation patterns thatresult in stagnant areas and dead zones, especiallywhen there are temperature differences between thewater in the tank and the water coming from the dis-tribution system. The configuration (number, size,and orientation) of the inlet(s) is critical to ensure thatstagnant areas and dead zones are mitigated.

Tideflex® Technologies continually conducts extensiveCFD (Computational Fluid Dynamics) modeling forvarious styles of tanks to determine the optimal con-figuration of the Tideflex® Diffuser inlets to ensuredead zones are minimized and mixing efficiency ismaximized (Figure 6).

Flow Rate

Jet V

eloc

ity

Jet Velocity vs. Flow

TIDEFLEX®

Pipe/Fixed Orifice

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0500 1000 1500 2000 2500

PENHANCED JET VELOCITY IMPROVES MIXING

POPTIMIZE INLET/OUTLET DESIGN

AwwaRF research has shown that distribution systemstorage facilities should operate in a completely mixedstate rather than plug flow (i.e. baffles). Mixing of waterinside a reservoir is dominated by the inlet flow momen-tum (flow x velocity). Maximizing the flow rate and/orvelocity improves mixing and reduces the fill timerequired to achieve a completely mixed reservoir.

Tideflex® Mixing Nozzles are inherently a variable orifice as they progressively open/close with the

increase/decrease in flow rate. This results in an opti-mized (non-linear) jet velocity profile at all flow ratescompared to a pipe and fixed-diameter orifice (Figure 4).At peak flow rate, the Tideflex® has an equivalent jetvelocity compared to a fixed diameter port. However, asflow rates decrease, the Tideflex® progressively closeswhich results in higher jet velocity. At lower flow,Tideflex® can generate 4-5 times greater jet velocity thana fixed diameter port.

TIDEFLEX®

Pipe

Fill

Tim

e (H

OU

RS)

Flow Rate

O U T L E T S

Fill Time Required forComplete Mixing

The advantage of the enhanced jet velocity is illustrated in(Figure 5) which is a graph of theoretical fill timerequired to achieve complete mixing. The equation isbased on tank volume and inlet momentum. At higherflows, the fill time required is nearly equivalent for thepipe/fixed orifice and Tideflex® Valve. However, at lowerflows, the Tideflex® mixes the tank faster than the pipesince the jet velocity and momentum are higher.

Elevated

Circular

Standpipe

Rectangular

Fig. 6

Fig. 5

Fig. 4

I N L E T S

������������������

������������������

Fill Operation Draw Operation

O U T L E T S

Rectangular reservoirs areprone to poor mixingbecause the corners of thetank dampen velocity andgenerate significant dead-zones. The TMS design elim-inates the corner effects andprovides uniform mixing.

Ground level tanks are constructed of avariety of materials including weldedsteel, concrete, and glass-fused bolt-ed steel. Typical inlet/outlet tankpenetrations are horizontalthrough the shell or verticalthrough the floor. Conventionaltank design included a commoninlet/outlet pipe of a diameterthat only generates 2 - 4 fps jetvelocity at average fill rates.Tideflex® Mixing Systems are general-ly sized for 8 - 10 fps jet velocity.

Prior to the Tideflex® Mixing System (TMS), onemethod used to separate the inlet/outlet pipeincluded a separate pipe around the perimeter ofthe tank or under the tank floor. This requiredtwo tank penetrations, the two pipes to be joinedin a vault outside of the tank, extra fittings, isola-tion valves, etc.

Tideflex® Technologies has various TMS designsavailable based on the dimensions of the tank.The TMS is connected to the tank penetration viaa flange fitting or coupling. The manifold pipe islaid along the floor on pipe supports. Tideflex®

Mixing System is available in various pipe materi-al. Typically, one set of Tideflex® Valves isinstalled on the far side of the tank for filling,another set of Tideflex® is installed on the nearside of the tank, near the tank penetration fordraining. Field data has shown the TMS resultedin increased and more consistent disinfectantresiduals throughout the water volume.

Circular & Rectangular

Ground Level Reservoirs

I N L E T S

Elevated

Storage Tanks

Inlet/Outlet Pipe

Inlet/Outlet Pipe

Dry Riser

Wet Riser

O U T L E T S

I N L E T S

Fig. 10

O U T L E T S

I N L E T SElevated tanks with wet risers are knownfor poor mixing because the “inlet" into thebowl is the large-diameter wet riser itself,not the smaller inlet/outlet pipe.Momentum is greatly reduced since thewater velocity entering the bowl is muchlower. In wet riser elevated tanks, theTideflex® outlet valves are installed in across fitting at the bottom of the wet risernear ground level (Figure 9). A verticalpipe is installed above the outlet valves andis braced off the inside of the wet riser.The TMS riser terminates just inside thebowl where one or more Tideflex® inletvalves are installed (Figure 10).

Another benefit of the TMS is that it willmitigate ice formation in dry and wet risertanks. A well-mixed tank will preclude stag-nant zones that are prone to freezing. Sincethe Tideflex® inlets are located higher inthe tank, they produce direct turbulenceon the water surface.

Elevated storage tanks come in manystyles and are typically constructed of steelor a composite (concrete and steel). In adry riser, the inlet/outlet pipe is installedinside the riser and penetrates the bowl.Near the penetration, Tideflex® outletvalves are installed in a flanged crossfitting (Figure 7). A TMS riser pipe isinstalled above the outlet valves and isbraced to the access tube (Figure 8).Multiple Tideflex® inlet valves are installedat various positions along the height of theriser depending on the dimensions of thetank, flow rates, and typical draw-downlevels. With this TMS configuration, freshwater is introduced into the tank near thetop of the bowl, and water is drawn fromthe tank toward the bottom of the bowl.

Fig. 9

Fig. 7

Fig. 8

W E T R I S E R

D RY R I S E R

StandpipesStandpipes are particularly prone to thermal strati-fication due to their depth. Stratification is mostsevere during summer when the inlet water iscolder than the water inside the tank. The colderwater is denser and tends to remain at the bottomof the tank (Figure 11). This results in very little orno mixing and long detention time in the upperportions of the tank. Also, the fresh water at thebottom of the tank is the first to be drawn into thedistribution system so short-circuiting in stand-pipes is prevalent.

For standpipes, the TMS inlet and outlet are typi-cally separated in the vertical direction - the inletstoward the top and outlets at the bottom. This con-figuration reduces or eliminates stratification. Inaddition, multiple inlet diffusers are used to pro-vide rapid mixing compared to a single inlet(Figure 12). The outlet valves are installed in afitting near the tank penetration (Figure 13). Thevertical riser pipe is installed above the fitting andis braced to the shell of the tank.

Another benefit of theTMS is that it will mitigateice formation. A well-mixed tank will precludestagnant zones that areprone to freezing. In addi-tion, since the Tideflex®

inlets are located higher inthe tank, they providedirect turbulence on thewater surface.

O U T L E T S

I N L E T S

55 60 65 70 75

90

80

70

60

50

40

30

20

10

0

A temperature study was conduct-ed on a 1.3 million gal. standpipein Dennis, MA. In the summer of2001, temperature data showedsevere thermal stratification. In thesummer of 2002 after the installa-tion of the TMS, the temperaturedata showed that stratification hadbeen virtually eliminated.

2001Prior

to TMS

Wat

er D

epth

(ft)

Temperature (F)

2002With TMS

Depth vs. Temp.

Fig. 12

Fig. 13

Fig. 11

Field study courtesy of Dennis, Massachusetts

CFDMODEL

TEMPERATURE STUDY BEFORE AND AFTER TMS

Across the country, municipalities are growing increas-ingly concerned about protecting America’s water stor-age tanks against contamination. Whether you’re facingrodents, birds, insects or the risk of tampering,Tideflex® Check Valves provide a reliable solution.

Tideflex® Check Valves can be easily slipped over orbolted to the end of overflow pipes. They are self-draining and will not leave standing water in the over-flow pipe. In addition the Tideflex® Check Valves arevery difficult to open manually, and virtually impossiblefor rodents, birds and insects to penetrate.

Unlike mesh screens and flapgate valves, Tideflex®

Check Valves will not corrode, dislodge or freeze openor shut. And installation is a snap. Tideflex® CheckValves provide a quick, cost-effective, virtually mainte-nance-free solution for municipalities coast to coast.

Overflow Pipe Protection

Security has become an important part ofany water storage facility, and Tideflex®

Technologies’ Overflow Protection productsplay a critical part in an overall security program. The tamper-resistant OverflowSecurity Assembly consists of our patentedTideflex® Check Valve, housed in a metalbody. The body allows an oversized valve tobe used, to retain the full flow capacity of theoverflow pipe. The assembly is ready-to-install; the pipe is simply cut and the assemblyis welded into place. Once installed, the valveis out-of-sight and unreachable. Designs foroverflow pipes fabricated from materials otherthan steel are also available.

��������

Weir Box

Overflow Pipe

Pipe Support

Tideflex Overflow Pipe Assembly

Tideflex Primary Overflow Protection

®

®

Overflow Pipe Protection

Tamper Resistant OverflowSecurity Assembly

The TMS improvesoverall water

quality withinfinished waterstorage reser-voirs byeliminatingstagnationand strati-fication. Byfilling anddraining

from oppo-site sides of a

tank, the TMSensures that all

water is continuallycycled. This eliminates the

“last in, first out” problemexperienced by most reservoirs

which use a common inlet/outlet point.The TMS also improves mixing by increas-ing the jet velocity of incoming water, and“aiming” it to provide the best mix for thesize and shape of the tank or reservoir.

The Tideflex® Mixing System has quicklybecome the leader in stored water mixingsystems. Look inside to see how Tideflex®

Technologies can engineer a system for yourapplication.

Eliminate Stagnation inFinished Water Storage Tanks

© Tideflex® Technologies, 2006, All Rights Reserved.

www.tideflex.com

The information presented in this catalog is provided in good faith.Tideflex® Technologies reserves the rightto modify or improve its design specifica-tions without notice and does not implyany guarantee or warranty for any of itsproducts from reliance upon the informa-tion contained herein. All orders are sub-ject to Tideflex®Technologies’ standardterms and warranty and are subject tofinal acceptance by Tideflex®

Technologies.

Tideflex is a registered trademark of Tideflex® Technologies.

RECYCLABLEPAPER

PHONE: 412/279-0044

FAX: 412/279-7878

The products contained in this brochure are covered under one of the following patent numbers: U.S. patent no. 4492253, 4523738, 4585031, 4603864,4607663, 5606995, 5727593, 5769125, 6412514, 701194, 5931197, 6016839, 2326603 U.K. In addition other U.S. and Foreign patents pending.

Tideflex Outlets

®

Tideflex Inlets

®

Improve Water Quality with the Tideflex® Mixing System (TMS)

TM 0508

Division Of Red Valve Company,Inc.

700 N. Bell Ave.Carnegie, PA 15106

NSF®