Three A certified strainers are used in many industrial applications of filtration to remove impurities from the liquid stream of their products. This improves product quality and ensures uniformity. Custom sanitary strainers are manufactured from stainless steel mesh (316L), but many other alloys are also used and customized depending on the application. Strainer mesh comes in many sizes and shapes and is either woven or welded together.
Types of strainers
Strainers are broken down into three main filtering categories:
- Coarse straining – for large particles
- Medium straining – for particles 75 to 1905 microns
- Filtration – for particles down to 40 microns
Polishing strainers to a very low surface roughness makes them extremely easy to clean, which is important for maintaining product safety and stream throughput.
Sanitary basket strainers are cylinder shaped and differ in the amount of square footage the filter surface area provides, the filter shape and density. Some common types are:
- Perforated strainer basket with a wire mesh liner
- Perforated strainer basket with a filter bag
- A wedge wire (slotted screen) strainer basket
- A wire mesh strainer basket
Perforated baskets are often necessary because wire cloth used in an application is too delicate by itself and needs support.
Strainer basket media options
When applications require filtration beyond what wire mesh provides, filter bags are a potential solution. Filter bags provide filtration rates from one to 1500 microns. Most industry standard sized filter bags will fit into SaniClean basket strainers. Filter bags are available in several different materials, including: polyester, polypropylene, nylon, Nomex, and Teflon.
- Felt bags - Filtration felt is a low-cost disposable media with depth-filtration qualities, high-solids loading capacity and are available in micron ratings from 1 to 200 microns.
- Monofilament bags - Monofilament mesh is an extremely strong material woven on precision equipment to ensure consistent pore sizes. It is re-useable in many applications and available in micron ratings from 1 to 1200 microns.
- Multifilament bags - This mesh is a low-cost, disposable filter media available in micron ratings from 75 to 1500 microns.
Filter bag characteristics
SaniClean’s “standard” filter bag comes with a stainless steel top ring for all size strainers.
- For polyester felt filter bags, “singeing” is recommended prior to fabrication. This added step helps minimize any fiber migration from the outer surface of the bag.
- For polypropylene felt filter bags, “glazing” is recommended prior to fabrication. This added step helps minimize any fiber migration from the outer surface of the bag.
- Filter bags can be supplied with handles or pull tabs sewn in, to ease filter bag removal.
Picking the best sanitary strainer
These are five key considerations to remember when deciding on which type of 3A certified strainer to use:
- Which industry is the strainer for?
- How is the strainer being applied?
- What is the size of the line and process flow rate?
- What percentage of solids must be captured?
- What is the particulate size requiring removal?
The right industrial filtration system will perfectly maintain product integrity without compromising safety, quality or cost.
To summarize a couple key points about strainers:
- Strainers come in many shapes and sizes, and are customizable depending on a variety of factors including application, size of production line, size of particulates requiring removal, flow rate and temperature.
- Strainer baskets are a common filter configuration and use different media like filter bags, to achieve the level of necessary product purity.
SaniClean Strainers, a Newark Wire brand, manufactures a complete line of industrial 3A certified strainers, assemblies, replacement parts, and filter media suitable for a wide range of applications and capacities. SaniClean Strainers are ruggedly built to withstand the most demanding production cycles. They are easy to clean and integrate into new or existing piping configurations. Contact them today and get their products and expertise working for your next filtration project.