Filtration Systems

When changing elements is the problem, change the system.

Self-cleaning and automatic backwashing filters, coalescers, skid-mounted systems, catalyst recovery, anti-scale dosing and filter aid media, for duties where consumable elements alone cost too much in spend, labour or stops.

Some streams run continuously with a solids load that would use up disposable elements every shift. Some carry oil or liquid aerosols that a particle filter does not separate. Some water lines scale and corrode long before they clog. Some processes filter through a precoat of filter aid, or recover a catalyst worth more than the batch. Each of these needs equipment built around the duty, not a bigger stock of elements.

When a consumable element is asked to do a system's job, the plant pays three times: in elements bought and disposed of, in operator hours at the housing, and in process stops for every change-out. Where oil passes a particle filter, or scale builds in a boiler or heat exchanger, the cost moves downstream into equipment and product. The right system removes the recurring cost at its source instead of paying it every cycle.

Each section below answers a different duty: filters that clean themselves by backwash, coalescers and adsorbents that separate oil and aerosols, skid-mounted and adaptor-head systems for portable or gravity-fed duty, closed catalyst recovery circuits, polyphosphate dosing against scale, cellulose filter aid for precoat filtration, and vapour-phase treatment. The question that selects between them is the same: what does the stream carry, how much, and what must leave the system.

Across the family, systems are specified for viscosities up to 200,000 cP, flows up to 10,000 m3/hr and filtration down to 3 micron, each subject to engineering review of the actual duty.

Self-cleaning filters

Gopani is an authorised distributor of Atlas Filtri self-cleaning filters. The Hydra range removes sediment and deposits from the filter surface by counter-current backwash: opening the drain ball valve at the bottom of the filter flushes the element, and a reflux block stops ejected water coming back in. The element goes straight back into service for further cycles, which is why these filters suit plants replacing sand filters or disposable sediment cartridges on water lines.

Rainmaster models are built for harvested rainwater, with a stainless net first stage, a wound cartridge on the three-stage model, and activated carbon as the final stage.

Photograph to shoot
Two-stage Hydra self-cleaning filter on a water line, transparent bowls showing the net cartridge, drain ball valve open with backwash water running to drain.
Hydra self-cleaning filters (Atlas Filtri, distributed by Gopani)
ModelStagesStage mediaIn/out connectionsStated limits
Hydra1Stainless steel net, polyester net or pleated polypropylene DOE cartridge1/2, 3/4, 1 1/4, 1 1/2 inch brass or plastic thread; 1/2, 3/4, 1 inch plastic NPT3,000 to 10,000 l/h capacity; 45 C; 8 bar (BSP), 8.6 bar (NPT)
Hydra Duo2Hydra first stage (stainless net, polyester net or pleated PP), then a finer stage1/2, 3/4, 1 inch brass or plastic BSP; 3/4, 1 inch plastic NPT45 C; 8 bar (BSP), 8.6 bar (NPT)
Hydra Trio3Hydra first stage, then two finer stages1/2, 3/4, 1 inch brass or plastic BSP; 3/4, 1 inch plastic NPT45 C; 8 bar (BSP), 8.6 bar (NPT)
Hydra Rainmaster Duo290 micron stainless net, then activated carbon or carbon block1/2, 3/4, 1 inch BSP or NPT, brass or plastic45 C; 8 bar (BSP), 8.6 bar (NPT)
Hydra Rainmaster Trio390 micron stainless net, 25 micron wound cartridge, then activated carbon or carbon block1/2, 3/4, 1 inch BSP or NPT, brass or plastic45 C; 8 bar (BSP), 8.6 bar (NPT)

All models are made from non-toxic materials stated as safe for potable water, clean by counter-current backwash through a drain ball valve, and carry a reflux block so ejected water cannot re-enter. Pressure and temperature are the stated maximums.

Automatic backwashing filters

Viscofil and Optifil run fully automatic and continuous. A metal fibre fabric or fleece retains the particles; once a set degree of contamination is reached, the element is cleaned by backwashing a small quantity of filtered medium while filtration continues. Viscofil works by depth filtration and holds gel particles; Optifil works by depth, surface or cake filtration depending on the duty. Canfil is an automatic system working by surface filtration; its data is issued on enquiry.

Photograph to shoot
Automatic backwashing filter with metal fibre element on a process skid, control panel and backwash line visible, operator for scale.
Automatic backwashing filters for process streams
SystemFiltration principleFilter materialStated dataNamed industries
ViscofilDepth filtrationMetal fibre fabric3 to 100 micron fineness; designed for 16 and 25 bar operating pressure; retains gel particlesFibre, foil, chemical, petrochemistry, foodstuffs
OptifilDepth, surface or cake filtrationMetal fibre fabric or fleeceDesigned for 10 bar operating pressure, higher on request; sizes for most flow ratesPulp and paper, fibre, chemical, electronics and photovoltaic, paint and coating, steel, galvanic and surface treatment, water treatment, sugar
CanfilSurface filtrationOn enquiryOn enquiryOn enquiry

Viscofil and Optifil backwash with a small quantity of filtered medium once a set contamination level is reached, and filtration continues during the backwash. Both run as completely closed systems.

Coalescers and oil removal

Liquid-gas coalescers. Interception, coalescence and drainage layers are pleated together with a micro-fibre media to separate sub-micron liquid aerosols from gas streams while limiting carry-over. The multi-layer pleat pack gives a high surface area at low pressure drop. Standard and amine-compatible versions are available, with stainless steel hardware, in formats that replace conical gas coalescing elements and most liquid-gas coalescing elements in service. Named duties: hydrogen recycle gas compressor protection, burner protection, lube oil recovery, molecular sieve and PSA protection, gas treating and sulphur recovery.

Clarysorb oil logs. Polypropylene melt blown microfibre and felt media inside a heavy polypropylene mesh cover on a polypropylene core. A log sits inside a filter bag or floats on a drum or vat and wicks free oil and grease from the liquid. Named duties: automotive paints, plating solutions, wastewater, parts cleaning and produced fluids. For oil and solids in one pass through a bag housing, see ClaryFil oil adsorbing bags.

Photograph to shoot
Pleated liquid-gas coalescer element with stainless hardware, cut away to show the interception, coalescence and drainage layers.

Skidded filter systems

When filtration is needed at several points in a plant, at different locations over time, or on lease rather than as a permanent installation, the complete system is mounted on a skid and moved as one unit. Scope is engineered per duty.

Adaptor head systems

For gravity-fed and low-pressure filtration, an adaptor head attaches directly to process piping and holds a filter bag. Thermally bonded side seams, integral handles and a custom ring size give a secure fit and a quick change-out.

Catalyst recovery systems

Closed, automated circuits built on Clarysynt sintered metal elements recover precious metal and Raney nickel catalyst with reverse-flow backwash and an integrated heel filter. The application page carries the engineering envelope: up to 99% single-pass recovery, 0.5 to 25 micron retention, and element life of 5,000+ batches as the design basis, each confirmed by a trial on your own slurry. Read the catalyst recovery application or the sintered metal technology.

Dosing and anti-scale cartridges

Dosafos and Dosaprop units release a controlled quantity of polyphosphate into the water so hardness salts do not deposit on the inside of pipes and devices, and so the lines corrode less. Dosafos doses non-proportionally; Dosaprop doses in proportion to flow. The Mignon Plus versions are compact 5 inch units for point-of-use duty. CPP HA cartridges combine a melt blown polypropylene filter block with polyphosphate crystals, so one element filters sediment and doses anti-scale.

Photograph to shoot
Polyphosphate dosing unit with transparent bowl showing the crystals, fitted on a water line ahead of a boiler.
Anti-scale polyphosphate dosing units and cartridges
ModelDosingConnectionsHeightsStated limits
Dosafos PlusNon-proportional polyphosphate crystals1/2, 3/4, 1 inch male or female; brass or plastic thread, BSP or NPT4, 5, 7, 10 inch35 C; 8 bar (BSP), 8.6 bar (NPT); hardness to 500 ppm as CaCO3
Dosaprop PlusProportional polyphosphate crystals3/4, 1 inch female; brass and plastic insert, BSP and NPT4, 5, 7, 10 inch35 C; 8 bar (BSP), 8.6 bar (NPT); hardness to 500 ppm as CaCO3
Dosafos Mignon PlusNon-proportional, compactOn enquiry5 inchPoint-of-use water boilers
Dosaprop Mignon PlusProportional, compactOn enquiry5 inchPoint-of-use water softening
CPP HA SX cartridgeMelt blown PP block with polyphosphate crystals insideDOE refill for Dosafos PlusOn enquiryFiltration plus anti-scale and anti-corrosion
CPP HA BX cartridgeMelt blown PP filter block for sediment and suspended impurities, with polyphosphateOn enquiryOn enquiryFiltration plus anti-scale

Dosaprop Plus: reinforced polypropylene head, SAN bowl. Refills as loose crystals or HA polyphosphate cartridges. Accessories on request: brackets, spanners, brass or plastic nipples with O-ring, lubrication kit. Hardness limit stated as 50 French degrees (500 ppm as CaCO3).

Filter aid and loose media

Gopani supplies cellulose fibre filter aids for precoat filtration and sludge conditioning, alongside its own filter elements and housings. For loose activated carbon (extruded, granular and powdered), see ClaryCarb activated carbon.

Cellulose fibre filter aid grades supplied by Gopani
GradeSource materialStated propertiesUse
LignocelNatural, untreated, unbleached wood fibreMany grain sizesTechnical filtration where further purification steps follow
RehofixNatural vegetable grain from untreated annual plantsCubic grain structure, free flowing; withstands up to 180 CAutomatic dosing equipment
RehoplusSelected Lignocel raw material pressed into pelletsFree-flowing, low dust, heavier pellets; withstands up to 180 CDewatering agent in sludge conditioning
VitacelPlant fibres from fruit, vegetable and cerealOn enquiryOn enquiry
ArbocelCellulose fibreOn enquiryOn enquiry
FiltracelCellulose fibreOn enquiryOn enquiry

Arbocel, Vitacel, Filtracel, Rehofix, Rehoplus and Lignocel are registered trade names. The fibres are produced from natural and renewable raw materials, are organic, dispose of easily, and can be used with precoat filtration systems.

VOC treatment

Vapour-phase treatment of volatile organic compounds is part of the Gopani range. Its scope is defined per enquiry from the vapour composition, flow and discharge target. Extruded activated carbon for gas-phase duty is listed on the activated carbon page.

Made by Gopani, or supplied

Gopani builds the catalyst recovery systems on its own Clarysynt media, developed the skidded filter systems, and makes the Clarysorb oil logs. Hydra self-cleaning filters are Atlas Filtri filters that Gopani distributes. For the automatic backwashing filters, coalescers, dosing units and cellulose filter aids, the maker is named on the quotation.

What we need from you

What the stream carries and how much of it; what must leave the system; flow, temperature and pressure; how often you stop for filters today; and who will operate the system. With those we recommend a system, or tell you that an element change is enough.

Tell us what the stream carries and what must leave the system.

Flow, solids or oil load, temperature, pressure and how often you stop for filters today. We tell you which system fits, or whether an element change is enough.