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Summer 2007 - Gravex

What's Inside

DualGuard III Condensate Septum

DualGuard III Construction Details and Advantages

DualGuard III Advantages

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DualGuard III
Condensate Septum

Graver Technologies DualGuard IIITM is a 100% polypropylene pleated precoat septum designed to operate in combination with Graver PowdexTM Condensate Polishing, Fuel Pool and Radwaste systems.

DualGuard III has superior iron removal ability of any pleated media combined with optimum precoat distribution along its entire length, even to lengths of 80 inches. This is an improvement over other available filters for this critical application. Better precoat distribution not only means more efficient Powdex usage, but that both filtration and ion exchange functions are more efficient. Because it is a pleated septum (as opposed to a pleated filter) we add a Precoat shroud over the pleats to provide a superior membrane surface. The precoat shroud, exclusive to DualGuard III, provides the following additional benefits:

  • An ultra smooth surface to allow for a completely uniform Powdex precoat
  • The prevention of resin accumulation in the pleated filter folds
  • A more thorough and complete backwash
  • The avoidance of particulate accumulation in pleat folds

DualGuard III optimizes the performance of Graver's Powdex system and is backed by the service and reputation of the leader in Condensate Polishing. Graver Technologies recommends that every nuclear Powdex Condensate system be upgraded to this state-of-the-art condensate septum. Fuel Pool and Radwaste systems should be upgraded as old metallic elements are replaced.

DualGuard III Construction
Details and Advantages

FEWER FILTER JOINTS (welds):
DualGuard III is constructed with only one weld joint to every 40 inch segment (with a 70˝ septum having a single welded joint). Weld joints can create the potential for weak links and uneven precoat. Our competitor uses 10 inch joined segments with a 70˝ filter having as many as six welded joints in a single filter!

SUPERIOR WELD JOINT TECHNOLOGY:
DualGuard III has the benefit of a secondary weld joint protection via a protective circumferential seal. This means less chance of weld failure.

STRONG OUTER SUPPORT CAGE:
DualGuard III uses a molded polypropylene cage in 40˝ segments versus our competitor's 10˝ segments. The combination of the design and construction factors makes the structural integrity of the DualGuard III far superior to any other condensate filters.

ENGINEERED SEPTA:
DualGuard III is pleated to a full pleat height and carefully fitted into the precoat shroud. The pleats are engineered to abut to the support cage and are supported and contained to maintain integrity during powerful air surge backwashes.

UNIQUE GASKET CONTAINMENT:
DualGuard III tube sheet bottom gaskets are contained and held in place by an end cap which is then sealed to the outer support cage. The gasket is prevented from sticking to the positioning cups and tubesheet fittings upon septa removal. This prevents one of the major issues associated with septa replacement and avoids the potential for the retrieval, rework and downtime common to other replacements.

FILTER MEDIA:
Calendared polypropylene media (1, 3, 5, 10 or 20 micron) is sandwiched between fine polypropylene plastic mesh for both upstream and downstream support.

DualGuard III Advantages

PRECOATABILITY:
Through the elimination of multiple weld joints, the DualGuard III has a very low pressure differential over its entire length. Powdex will precoat evenly from bottom to top without the detrimental "Christmas tree" pattern found with filters. This uniformity of applied Powdex ion exchange resin itself extends the life of the DualGuard III. Other filters will have areas with low precoat density (or bare spots) and will become locally fouled by premature crud breakthrough.

STRENGTH:
DualGuard III is designed as a precoatable and back washable septa, not a filter. Air surge necessary for an effective backwash is powerful and the septa must be designed and constructed to endure backwashes and maintain integrity during its life span. The DualGuard III molded outer cage is designed to withstand maximum air surge backwashes. The full pleat design also provides the strength necessary toprevent the filter from failure creating a resin leak and/or crud bypass. Precoatable surface area is never sacrificed; Powdex adheres evenly across the outer support cage and traps crud and provides ion exchange capability. Effluent from the Powdex layer next flows through the precoat shroud and then flows through the full area of the pleated media providing both excellent precoat and filter capability. With hundreds of DualGuard III installations, there have been no failures.

TIERED FILTRATION:
An exclusive design feature of the DualGuard III septum is that it removes large range ofparticles with the Powdex precoat, while the very smallest particles migrate through the precoat are removed by the fully functional pleated filter media. Resin never touches the pleats so the pleated area is not restricted by resin filling the pleat folds; the full pleated surface area is available for ultra fine filtration making the DualGuard III the best iron stopper ever made.

SURFACE AREA:
Graver Technologies DualGuard III's are designed to match the design of Graver backwash system capacity. DualGuard III's will be fully washed and clean after each backwash sequence.

POWDEX EFFICIENCY:
By far the largest benefit of the Dualguard III is the improved operating efficiency it provides along with economical resin usage. Ion exchange allows one equivalent ion of impurity to be exchanged for one equivalent exchange site on the resin. However, a minimum precoat thickness is required for proper contact time. Graver Technologies recommends 0.20 dry pounds of Powdex per square foot of circumferential area, which will provide minimum 90% ion exchange efficiency. Insufficient amounts of precoat thickness can reduce ion exchange efficiency to as low as 40%. Because DualGuard III precoats souniformly, the recommended dosage can be maintained without adding excess ion exchange resin. Other available filters will require as much powder to achieve even a thin layerprecoat. The DualGuard III by Graver Technologies delivers maximum performance for both ion exchange efficiency and filtration with maximum septa life without risk of failure.



Superior Products & Global Reach

Whether your business is around the corner or around the world, Graver Technologies can support you with superior products and services. Our ion exchange, adsorbent, filtration and membrane products deliver exceptional performance in some of the harshest process environments in North America, Europe, Asia, the Pacific Rim, South America and Africa.

Graver Technologies is a member of The Marmon Group of companies, an international group with more than $6 billion in annual sales. Around the corner or around the world, Graver Technologies is a fast-growing company with the technical resources and financial strength that make us the perfect partner for your business.


© Graver Technologies, 2008.

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