SMC AFF8B-03 Main Line Filter Rc 3/8, 3 um

A filter for the main air line

AFF8B-03 is a main line filter from the SMC AFF series. It is fitted in the main piping, close to the compressor and the air dryer, to remove oil, water and foreign matter from the compressed air. Clean air at that point protects the downstream dryer, the precision filters and the pneumatic equipment, and reduces valve and cylinder faults.

The code reads AFF (series), 8B (the body size for 3/8 Standard), no thread letter (so the Rc thread) and 03 (a 3/8 port). The suffixes for accessories or options are left out: B would add a bracket, C or D an auto-drain, J a drain guide, R reversed IN-OUT and T an element service indicator.

Technical specifications

Where it fits in the air system

A main line filter is the first stage. Compressor exhaust carries oil mist and water, and the filter removes the larger part so that the next stage, such as a micro mist separator or a dryer, is not overloaded. The usual order in SMC catalogues is air filter, then mist separator, then dryer, then finer filters near the machine, but the layout for each plant depends on the quality of air needed.

The rated flow is the maximum at 0.7 MPa and it falls at a lower pressure, so use the maximum air flow chart in the catalogue to match the model with the inlet pressure and the largest flow, rather than choosing only by port size.

Maintenance

The element is replaced every two years or earlier when the pressure drop reaches 0.1 MPa; the optional element service indicator (T) shows when this happens. Water collected in the bowl must be drained, by hand or with an auto-drain accessory, otherwise it can be carried downstream. A bracket assembly BM53 is listed in the catalogue for this body size.

Install the filter vertically with the flow in the direction of the arrow, and do not use it with fluids other than compressed air. If the line must be serviced without a shutdown, plan a bypass or a shut-off valve on each side, and give enough space below the bowl for draining and for removing the element.

Remember that a filter adds a pressure drop. A model that is too small for the flow wastes energy at the compressor, so size for the real peak flow and keep a margin.

Related SMC products: SMC AF30-03 Modular Air Filter 3/8 Rc, SMC AL30-03 Modular Lubricator 3/8 Rc, SMC AR30-03 Modular Pressure Regulator 3/8 Rc, SMC AW20 Air Filter &amp, SMC AFM30-03 Mist Separator 0.3 Micron 3/8 Rc and SMC AFD30-03 Micro Mist Separator 0.01 Micron 3/8 Rc.

Documents and quotation

The SMC AFF catalogue PDF below has the how-to-order page, specifications, flow graphs, dimensions and the precautions. Please confirm port size, thread type, drain and options before ordering. Related parts are listed under Regulators. Seven Star LLC is an independent supplier and quotes the exact code on request.

AFF8B-03 and the Current AFF8C Model

The AFF8B-03 is from an earlier generation of the SMC AFF series. In the current AFF catalogue, the same body size is listed as the AFF8C. The current equivalent of the AFF8B-03 with an Rc 3/8 port is therefore AFF8C-03. The table below gives the data published for the AFF8C, which you can use when comparing or replacing an installed AFF8B-03.

Port positions and dimensions can differ between generations, so check the dimension drawings before you replace an installed unit.

How a Main Line Filter Works

Air enters the bowl and passes through a cotton paper element from the outside to the inside. Solid particles of 3 µm and larger are trapped by the element. Water and oil droplets coalesce, run down into the bowl and are discharged through the drain cock or an auto drain. Because the AFF removes the bulk of the contaminant load, it protects the dryer and extends the life of the finer filter elements downstream, such as the AM mist separator and the AMD micro mist separator.

Selection & Ordering Guide

• Size: choose the body by the maximum flow capacity line at your actual inlet pressure, not only by the port size. The catalogue explains the procedure and gives the graph.
• Thread: Nil = Rc, F = G, N = NPT.
• Accessory: B = bracket, supplied but not assembled.
• Auto drain: C = N.C. (closed when pressure is not applied), D = N.O. (open when pressure is not applied). Without either, the filter has a drain cock.
• Options (current AFF-C): F = FKM seals, H = medium pressure 1.6 MPa, J = 1/4 drain guide, R = IN-OUT reversal, S/U = differential pressure switch, T = element service indicator, V = white vaseline.
• Modular connection: the AFF2C to 22C bodies can be connected modularly with the AM, AMD and other units of the same size.

If you are replacing an AFF8B-03, our team can help confirm the correct ordering code for the current model and the matching element.

Installation & Maintenance

• Install the filter downstream of the compressor aftercooler and air tank, before the dryer and finer filters.
• Mount it vertically with the bowl down, and follow the IN and OUT direction marked on the body.
• Drain the condensate regularly. Where the line is unattended, use an auto drain.
• Replace the element after 2 years or when the pressure drop reaches 0.1 MPa, whichever comes first. Exhaust the pressure before opening the bowl.

Typical Applications in Oman & the GCC

The AFF8B-03 class of filter is used for compressed air treatment in workshops, process plants, packaging lines, water treatment and oil and gas facilities. In the hot, humid coastal conditions of Oman and the GCC, compressors carry a lot of water, so a well-maintained main line filter is especially important.

Why Source the AFF8B-03 from Seven Star LLC

Seven Star LLC supplies SMC air preparation equipment, including AFF main line filters, AM and AMD mist separators, elements and auto drains, across Oman and the GCC. Request a quote, and our team can help confirm the correct ordering code for a direct replacement.