DOMESTIC SOLUTIONS
Filtration that assures crystal clear water
Omicron automatic screen filtration assures brilliantly transparent domestic water for residential and commercial buildings, hotels, and other high-flow applications.
With our enormous range of sizes, configurations, and easily customized options to meet specific requirements, we assure optimal performance while accommodating budget constraints.
Value of correct sizing
A simplex filter with a large screen area assures not only reliable operation but significant cost savings too.
While others offer complicated, expensive manifolds of small filters, our efficient designs routinely provide fine filtration at high flow rates through a single housing.
There are three essential values that must be factored into the correct designation of an automatic screen filtration system:
Maximum flow rate (GPM)
Filtration degree
Incoming pressure
Omicron Specifications -- How to select the optimal Omicron solution.
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For most domestic water filtration applications, there are three options: 10, 18 or 25 micron. When making a selection, it is truer to think of a filtration degree not as an absolute. but as percentage reduction of overall Total Suspended Solids (TSS) or Turbidity (NTU).
Finer filtration (a smaller micron degree) reduces more TSS / NTU. Note: A filtration screen is not a "pass/stop" barrier depending on its micron rating, since particles are soft and clump together as they impact the screen, forming an increasing filter cake.
A useful way to understand how screen filtration behaves is to keep in mind that a 25 micron screen is 19% open perforation, 81% stainless steel barrier.
At 18 micron the ratio is 13% open / 87% closed.
At 10 micron the ratio is only 6% open / 94% closed.
One takeaway from the above is that the finer the screen, the more pressure is required for reliable filtration.
Note: The impact on actual water transparency is significant at 10 micron, it is far less observable at 25 micron.
In typical New York City water conditions, we recommend as specification guidelines:
For 10μ filtration 80 - 100 cm2 of screen area for each GPM of the max flow rate.
For 18μ filtration 65 - 90 cm2 of screen area for each GPM of the max flow rate.
For 25μ filtration 50 - 80 cm2 of screen area for each GPM of the max flow rate.
THE RATIO OF SCREEN AREA TO FLOW RATE IS A PRINCIPLE OF MECHANICAL PHYSICS THAT MUST BE ACCEPTED, IN ORDER TO ASSURE RELIABLE OPERATION.
Allowing more screen area is always advantageous, since water conditions are highly variable.
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If water is sent to a roof tank, it is simpler to determine a max flow rate since it is limited by the capacity of the house pumps, and how many will operate at the same time.
The max flow rate of a constant pressure system can be more variable as it depends on real-time demand.
However the max flow rate value is determined, it must be established definitively in order to size filtration correctly.
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All screen filtration requires adequate pressure to operate. As a rule, the minimum threshold is higher for finer filtration than it is for coarser.
For 25 micron, below 45 psi at the filter inlet becomes risky for reliable operation.
For 18 micron, we advise a minimum of 50 psi.
For 10 micron, at least 58 psi should be available.
Filters running off net street pressure usually include a flush line pump to boost pressure during the critical flush cycles when pressure is most critical. Note these pumps boost pressure by no more than about 8 psi.
A solution to low pressure environments -- which are increasingly common -- is to locate the filter downstream of the house pumps, thereby leveraging much higher pressure to support reliable 10 micron filtration.
Omicron offers high pressure systems to accommodate this option.
Up to 150 psi, no special build is required. Above 150 psi, we offer two versions: PN16 for up to 230 psi, or PN25 for up to 360 psi.
High pressure builds -- installed downstream of the house pumps -- are especially valuable to accommodate installation in equipment rooms when located above grade in response to flood zone considerations.
What to decide -- options
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In order to make the most efficient use of available space, determine which filter orientation will be more suited for your needs and available space. All our models are available in both orientations. The most common orientations are V for the 5300 (smallest) and H for those between 8000 and 21300.
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The decision of which material to choose should be based on the balance of desired cost and durability. While 316L stainless steel is the most commonly used material due to its longevity, using coated carbon steel (CCS) can result in significant cost savings. Note that product water quality is no different when housings are CCS instead of stainless.
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Single filters generally are ideal for applications where a low flow rate is adequate, or the micron degree is no finer than 18. Twin manifolds are optimal for higher flow applications especially when 10 micron is specified.
Important note: Unlike pump skids, a duplex (or greater) manifold confers no redundancy to the system. Filters manifolded run 100% of the time in parallel. Ordinarily, multiple filters are specified to accommodate the required flow rate only. There should be no presumption that one will carry the load while the other is off-line. Should that be necessary, true redundancy must be specified as part of the design.
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Adding a flush line pump is important when an additional 8 lbs. of pressure during backwash cycles will make an operational difference to support system reliability in applications with marginal incoming pressure.
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Failsafe bypass assures automatic bypass of the filtration system during the unlikely event of a power failure. In the event of a power failure the system is immediately isolated and water continues to flow to the building or other application(s).
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A check valve protects the fine screen from the possibility of reverse flow that can effectively destroy it. Including a check valve is highly recommended.
Here is an example of a complete specification of a building water filter. We highly recommend referencing the minimum screen area required to support the max flow rate / micron rating.
MINIMUM SCREEN AREA/SYSTEM: 33,000 CM2
FLUSHING CRITERIA: DIFFERENTIAL PRESSURE OF 0.3 BAR (4.4 PSI). TIME INTERVALS AND MANUAL INITIATION AVAILABLE.
