A bag filter system is one of the most popular filtration methods for liquid process applications. It provides a versatile, cost effective and consistent filtration system suitable for a broad range of applications from small batch operations to bulk processing. Bag filter housings are available in a wide range of materials and sizes, and can handle any fluid types and flow rates in the range of 1m3/hr to 640m3/hr. Replacement filter bags are selected from the broadest possible range of media. The required filter media is determined by the size of the particles to be removed (0.5 – 1500 microns), the type of particles to be removed (deformable or non-deformable), the required retention efficiency (60 to >99%) and the chemical and temperature compatibility of the media.
Standard Filter Bags
Allied Filter Systems Ltd manufactures high quality liquid filter bags to fit standard size filter vessels, as well as custom designed products where requested. The constituent materials have been chosen for their purity, consistent high quality and repeatable performance. Filter bags are available in traditional stitched form or with a fully welded construction, and are fitted with a comprehensive choice of rings.
Sewn Needlefelt Filter Bags
Needlefelts are a versatile and cost effective media providing a high solid holding capacity for both non-deformable and deformable, gelatinous particles. By means of a depth filtration mechanism, particles penetrate and are captured throughout the depth of the filter media.
Fully Welded Filter Bags
All seams are welded rather than sewn, and combined with our positive sealing moulded Welseal (polypropylene or polyester) welded ring, no process liquid can bypass through needleholes caused by the sewing process or around a traditional metal ring. The Welseal ring forms a 360o hermetic seal between the filter bag and housing, ensuring that fully welded filter bags perform to a higher efficiency than a sewn equivalent.
Mesh Filter Bags
Mesh filter bags provide surface filtration – a ‘sieving’ mechanism, causing particles larger than the pore size of the media to be captured on the surface of the media. They are excellent for removing non-deformable, solid particles and have no fibre migration.
Custom Made Filter Bags
For unique applications requiring liquid filter bags which fall outside of the scope of our standard range, our manufacturing flexibility and expertise enables us to design and produce custom made products which perfectly meet your needs.
Food & Pharmaceutical Grade Filter Bags
Bag filters, when used in food, beverage or pharmaceutical applications, must conform to EC directives governing plastics in contact with food. Migration limits of contaminants from polymers into a food product have been imposed, and independent testing and certification of component materials is required to ensure these regulations are satisfied. Stringent manufacturing and warehousing conditions as well as special packaging procedures are also required to eliminate other sources of contamination.
Extended Life Filter Bags
Increased thickness of the filter media compared to that of the equivalent standard felt filter bag enables an increased retention of particles. In addition, the extended life filter media has a graded density structure i.e. progressively smaller particles are captured as the fluid follows a tortuous path through the media, stopping the filter bag from blinding prematurely. The result is a filter media with a higher dirt holding capacity, leading to increased filter bag lifetime.
Multi Layer Felt Filter Bags
Multi Layer felt filter bags provide graded density, multi stage depth filtration in a single filter bag. A high dirt loading capacity and superior filter bag lifetime is achieved by selecting the optimum micron ratings of the pre-filtration and final filtration layers in accordance with the needs of the filtration process. Multi Layer filter bags can be produced with 2 or 3 layers of polypropylene or polyester needlefelt, and to further enhance performance, a layer of extended life felt can be incorporated. An optional mesh exterior cover can also be provided.
Mega Depth Series
The Mega Depth multi-layered filter bag range has been developed to optimise filtration efficiency, lifetime and dirt holding capacity in either a continuous or batch process. The constituent filter bag layers are customised and selected to meet the needs of the specific application, giving a filter bag which optimises the filtration process.
High Capacity Filter Bags
Newly installed filter bag housings or existing systems can utilise High Capacity filter bags, which increase the filtration surface area by 70% compared with a similar sized standard bag.
The High Capacity bag is situated within a stainless steel filter basket with inner support core. Baskets can be supplied to retrofit existing standard size filter bag housings. Liquid enters the bag and flows through both the outer surface and the central core, enabling higher flow rates to be achieved compared to the equivalent sized standard filter bags.
MBP 200 Series High Efficiency Filter Bags
The MBP 200 Series high efficiency bags are available rated at 1-25 micron, and perform to efficiencies >95%. The filter bag consists of up to 4 layers of melt blown polypropylene media, including an outer cover to prevent fibre migration into the filtrate as well as providing added support to the filtration media. The high density of small diameter fibres compared to that of a standard needlefelt enhances particle retention, leading to superior, highly efficient filtration.
MBP 300 Series High Efficiency Filter Bags
Allied Filter Systems Ltd has developed the MBP 300 Series, a unique range of absolute rated filter bags rated from 1 – 10 micron, performing to an efficiency of >99% at the stated micron rating. For processes requiring absolute filtration, the use of filter cartridges has previously been the method of choice to achieve high performance in critical applications with consumable filter elements.
OA Series Filter Bags
The OA Series filter bags have a high oil and hydrocarbon absorption capacity, and are available rated at 1-25 micron with particle removal efficiencies >90%. The filter bag has 3 or 4 layers depending on micron rating, and includes a central polypropylene microfibre layer with enhanced oil and hydrocarbon absorption properties, and an outer cover to eliminate fibre migration and give added support to the filter media. It is constructed with sewn seams, with a choice of any ring type, including our Welseal polypropylene collars.
Oil Absorption Insert
For processes requiring oil removal from a liquid stream, Allied Filter Systems has introduced the new Oil Absorption Insert. The insert is simply positioned within a standard filter bag, which can be any single layered type selected in accordance with the particle retention needs of the process. Use of the insert requires no modification to the baskets of standard filter housings. The insert is available in size 1 or 2, and has a 100% polypropylene construction.
Oil Absorbent Booms
Oil Absorbent Booms are manufactured from hydrophobic polypropylene microfibre, and are used to absorb silicone’s and hydrocarbons such as fuel oils, hydraulic oil, petrol, diesel, motor oil, jet fuel and kerosene. Booms are normally produced with ties to enable them to be suspended on the surface of a tank, and are manufactured under silicone free conditions.
High Efficiency Filter Bags – 500 series
The 500 Series filter bag from Allied Filter Systems Ltd contains in excess of 5m2 of materials, and provides a very high oil and dirt holding capacity at high efficiency. It is constructed from 100% meltblown polypropylene microfibre filter media, giving a broad chemical compatibility. The constituent media has enhanced oil absorbent properties, and coupled with the high surface area, the 500 Series is most commonly used for applications where a high amount of oil absorbance is required. For example, it is widely used in the automotive industry for heavily contaminated electrocoat baths.
WA Series Filter Bags
Allied Filter Systems has developed the water absorbent (WA) series for processes requiring water removal from hydrocarbons. Available in both size 1 and 2 with a choice of either plastic or metallic rings, the WA series filter bag can reduce water content from several thousand ppm to acceptable levels in line with the needs of your process. As the filter media absorbs water by hydrogen bonding, the filter does not release water under pressure.