The heart of any filtration system is the screen. It is the barrier that keeps downstream systems protected, ballast water free from invasive species, and RO membranes safe from upstream contaminants.

Filtersafe’s patented filtration technology all started with a vision to engineer a dedicated seawater durable filter that could handle filtration of microscopic organisms without letting the microscopic organisms through or clogging. After years of R&D our engineers created our unique smartweave screen, utilizing a patented manufacturing and sintering process that places our screen leaps and bounds above the alternatives.

By using a combination of weave wire filtration screens, protective screens, and a reinforcement layer, the innovative, highly effective screen filters out sediment and microorganisms, providing invaluable filtration support no matter where it’s installed.

Why It’s Important

As the heart of a filter, the screen provides two key benefits that make or break the functionality of the filter – it’s ability to filter out particles down to the designated micron and its ability to work without clogging.

If a filter can’t be trusted to filter down to the required micron level, many problems can occur. In an industry such as ballast water filtration, allowing organisms in the ballast tank can cause a ship to be in non-compliance with the International Maritime Organization’s D-2 regulations, and result in heavy fines for shipowners. In agriculture, it can result in sediment getting through to the drip irrigation lines and clogging the pipes and nozzles, resulting in expensive maintenance. Every filter request comes with a request to filter down to a specific micron level because anything bigger than this size will cause problems downstream. It’s imperative that end users can trust that their filters are filtering down to the level requested.

The second issue, clogging, is deeper than just the screen stopping because of a clog. Clogging can also refer to any unexpected reduction in the filter’s flow rate, which can cause cascading problems. Firstly, many filters clean based on the concept of differential pressure – that is the pressure inside of the filter is higher than that outside and this difference in pressure triggers the screen to be cleaned. If the screen cleaning mechanism can’t properly remove the debris building up on it, the buildup of debris can reduce the clear opening of the filter mesh and significantly reduce the flow through the filter. Even before it clogs completely, this phenomenon can reduce flow through the filter by up to 80 or 90%, effectively rendering the filter clogged even though it still can pass the process fluid.

On a cargo ship this reduction in water can slow or even halt the loading or unloading of cargo, as the ship can become dangerously unbalanced as products are moved on and off and there isn’t a respective change in balancing ballast water. The additional time in port not only throws of the ship’s schedule down the line, but can result in expensive additional docking fees while in port. In many industrial applications a clogged filter can simply shut down the process its involved in – in a food production facility this means stopping production, but if the filter is involved in a HVAC/cooling tower application, the particles that aren’t filtered out can cause corrosion within the system, or even more dangerous cause the system to overheat and shutdown as the vital cooling water isn’t being provided.

Now that we understand how important a properly functioning screen is to various industries, let’s learn more about how Filtersafe’s smartweave screen works.

How It Works

The basis for Filtersafe’s smartweave screens is our exclusive weave-wire mesh layer. This is the layer that determines the micron level down to which the filter filters, and can range anywhere from 10-500 microns, depending on the application. In order to enhance the strength of the screens (and we’ll see below flimsy screens are a real problem), the mesh layer is covered on either side by a protective layer. In addition, on the outside of the screen is an additional perforated reinforcement layer, for enhanced durability.

In order to keep the 4 layers compact and without rubbing (which can lead to wear and tear of the individual layers and compromises the filtration integrity and can also encourage corrosion within the filter screen) we have a unique sintering process, which allows our 4 layer screen to be less than 3 mm thick. The combination of the unique use of weave wire along with the additional protective layers also gives us an unrivaled effective screen area. This means that smartweave screens are able to trap a huge amount of particles while still maintaining a high flow rate (all within a small footprint). Lastly, Filtersafe is able to offer its proprietary screen technology in several different stainless-steel varieties including – 316L, 904L, and SMO254, depending on application requirements.

What is Sintering

Sintering entails heating elements of the 4 layers so that the metals of each layer bond together, without the use of any bonding agent or other external materials, and without actually melting the metal. Sintering produces a secure, reliable bond between the layers, and is especially suited to wire mesh, as it allows each wire to be securely attached in place at the same time. This is especially important as the numerous strands of wire can easily become loose and start fraying if not properly secured together – threatening the integrity of the filtration element cut point.

A Closer Look At Other Screens

The smartweave screen technology especially stands out when compared to the other screen technology options available. Let’s see how smartweave compares to the competition.

Floating weave wire vs smartweave sintered

Floating weave wire screens are similar to our smartweave screens in that they both contain weave wire and therefore have exceptionally high open area and higher flow rates than other screen options, while trapping 8 times more organic matter than wedge wire filters – however the similarities end there. Floating weave wire screens are a popular choice as they are much cheaper to manufacture than our sintered alternative, and therefore cheaper to buy. However, the cost savings in the short term quickly result in expensive problems for buyers.

The screens are called ‘floating’ because the screen layers aren’t sintered together and a cross-section looks like they are floating atop one another. Each layer of the Floating weave wire screens needs to be more robust because it can’t rely on the strength it neighboring layers which leads the overall width of the screen to be 12 mm thick or more with the actual fine filtration layer (working mesh) placed further away from the surface of the screen and the gap between the inner protection mesh and the working mesh can be 2.5mm or more allowing high slippage flows when being cleaned. Alternatively, smartweave screens are only 3mm thick with the working mesh being only 0.5mm away from the inner protection mesh. This increased thickness between the layers can make it harder for nozzles to properly clean the screen (an issue discussed in greater depth in our article about our patented nozzlex technology). Aside from the problems their thickness can cause with cleaning, as the screen layers ‘float’ they can move with changes in pressure within the filter, rubbing against each other. This can cause two problems – corrosion from the steel rubbing and reduced integrity of the weave wire layer which puts the filtration degree in jeopardy. Just one small hole in a screen changes the filtration degree of the entire screen.

Candle filters vs weave wire

Candle filters get their name from the long, tubular shape of the filter. These types of filters are normally wedge wire and rely on metal barriers to filter water and are cleaned through backflushing. While theoretically candle filters are supposed to be able to filter to a finer degree, the backflushing process can allow fine particles to come through. Unlike precision nozzles which suck off debris at the point of nozzle contact, backflushing reverses the flow of water to clean and the force of the reversed flow can weaken the filter’s welds over time,  reducing the durability of the filter. In addition, when fine filtration is required, the open area and porosity of the filter decrease dramatically, resulting in a much lower flow rate.

As discussed above, because smartweave screens are sintered, the layers of the screen don’t rub together, resulting in enhanced durability.  Weave wire screens can also be used on-line or in-line, while candle filters can only be in-line. Weave wire screens also have up to 6 times the open area of wedge wire, resulting in a higher flow rate that can be incredibly valuable if time is of the essence (such as when you are trying to fill up a ballast tank while unloading cargo, or are filtering water at a desalination plant for hundreds of thousands of people). Lastly, while more superficial, weave wire screens tend to leave water looking cleaner, even with larger filtration degrees.

Screen vs sand filters

Sand filters are one of the oldest technologies that are still in use. Sand filters are a common choice when the user wants to remove suspending particles and don’t require a high flow rate. They can be economical choices, but overall, have many cons when compared to automatic screen filters. The table below gives a clear overview on the benefits automatic screen filters have over sand filters.

Feature	Sand Filter	Filtersafe Filter
Size	Big	Compact
External Backwash Pump	Needed	Not needed
Blower	May be Necessary	May be Necessary
Clean water for Backwash	Needed	Not needed
Filtration Degree	25 microns and above (Unless chemical is used)	25 microns and above (Unless chemical is used)
Downtime for Backwash \ Flushing	10 to 20 minutes. System isolated for backwashing unless with standby unit.	Flushing doesn’t affect system flow. Approximately 30 seconds for full recovery.
Amount of Backwash water	Easily 6% of total flow	Less than 1% of total flow
Media Replacement	Yes	Not needed
Chemical Use	Yes, to achieve fine filtration	No chemical use

 

Let smartweave Filter For You

smartweave works to its full potential when paired with our nozzlex proximity nozzles, and results in our EVERCLEAR automatic filtration cycle technology. The EVERCLEAR autonomous self-cleaning filtration cycle works with low operating pressure, minimal water for flushing, and is NOT a backwashing sequence, for 100% screen cleaning every cycle.