SMC AF30-03 Modular Air Filter 3/8 Rc

The first stage of an air preparation line

AF30-03 is the body size 30, Rc 3/8 air filter of the SMC AF modular series. It removes solid particles and bulk condensate from compressed air before it reaches regulators, valves and cylinders, and it is the usual first block in a filter, regulator and lubricator chain. Because the AF is a modular type, it can be joined to AR regulators, AL lubricators and other modular units by spacers and brackets without extra piping.

The code is made of the series and body size (AF30), the port size (03 is 3/8) and then optional letters. As ordered here, nothing follows 03, which means Rc thread, no bracket, no auto drain, a polycarbonate bowl, a drain cock, left-to-right flow and the MPa name plate. The catalogue example AF30-03BD-2R shows how letters add a bracket (B), a float-type auto drain (C normally closed, D normally open), a metal bowl (2), and right-to-left flow (R).

Technical specifications

Bowl, drain and option choices

The standard polycarbonate bowl is the cheapest option, but the catalogue points to its chemical data page when a different environment is involved: some compressor oils and cleaning solvents attack polycarbonate, which is a reason to choose the metal bowl (code 2) or nylon bowl (6). A metal bowl with a level gauge (8) allows the condensate level to be seen, and on the current AF30-D a transparent polycarbonate bowl guard is fitted as standard to protect the bowl on the plant floor.

The drain can be manual (drain cock, the default), piped away with a drain guide (J, a 1/4 drain guide without valve function, or W, a drain cock with barb fitting) or automatic with a float-type auto drain (C is normally closed, D is normally open). A float drain is the better choice on any filter that is hard to reach, because a full bowl passes liquid downstream.

Using the AF30 correctly

Install it with the bowl vertical, flow in the direction of the arrow on the body, and drain the bowl regularly if there is no auto drain. Check the element for a pressure drop at the inlet pressure of your system, and replace it at the interval the manual gives. A 5 micrometre element does not remove oil aerosol: for oil-free air in instrument or painting duties, follow the filter with the AFM30 0.3 micrometre mist separator or the AFD30 0.01 micrometre micro mist separator.

In hot, dusty Gulf locations the maximum fluid temperature of 60 deg C and the plastic bowl should be borne in mind; keep the filter out of direct sun and away from heat sources.

Documents and quotation

The SMC AF catalogue linked at the end of this page includes the how-to-order table, specifications, options and dimensions for the current AF20-D to AF60-D range. Please confirm thread type, bowl, drain and bracket before ordering. Other air-preparation items are under Regulators. Seven Star LLC is an independent supplier and quotes the exact code on request.

AF30-03 and its current successor, AF30-03-D

The code AF30-03 belongs to the earlier generation of the SMC AF modular filter. SMC has superseded it with the -D series, and the current equivalent is AF30-03-D. The product photo and the official catalogue linked at the end of this page show the -D version. Its body size, Rc 3/8 port and 5 µm rating are the same, so in most systems an AF30-03 is replaced by an AF30-03-D. The -D series has a few practical changes: a transparent polycarbonate bowl guard, so the condensate level can be seen from all around; a bowl with a lock button that has to line up with the groove in the body; and new spare part numbers. Before ordering, check the part numbers of brackets, spacers and bowl assemblies against the -D catalogue rather than an old parts list.

How the AF30-03 air filter works

Compressed air enters at the IN port and passes through a deflector (baffle), which sets up a swirling flow in the bowl. Centrifugal force throws water droplets and heavy particles against the bowl wall, where they run down into the quiet zone below the baffle. The air then flows from the outside to the inside of the filter element, which retains solid particles down to the nominal 5 µm rating, before leaving through the OUT port. The collected condensate is drained manually through the drain cock, or automatically if a float-type auto drain is fitted.

In the N.C. auto drain (AD37-D on the AF30-D), the drain stays shut when the bowl is not pressurised. It opens when the float lifts on rising condensate while the line is under pressure. In the N.O. type (AD38-D), the drain is open whenever pressure is removed, so the bowl empties every time the line is shut down. SMC warns that with a small compressor (0.75 kW, discharge flow under 100 L/min (ANR)), air may leak from an N.O. drain at start-up, and recommends the N.C. type in that case. With the N.C. type, condensate that has not reached the float level stays in the bowl when pressure is removed, so SMC recommends releasing it before the end of each working day.

Selection & ordering guide for AF30-03-D

The current how-to-order structure is: AF30 – thread type – port size – options – semi-standard – suffix -D. Typical choices for this body size are:

When more than one option is needed, the letters are written in alphanumeric order. The catalogue example is AF30-F03BD-2LR-D: G 3/8 thread, bracket, N.O. auto drain, metal bowl, element service indicator, and right-to-left flow. Some combinations are not allowed: C and D cannot be combined with the J drain guide, and the W barb fitting is not available with metal bowls 2 and 8. Our team can help confirm the correct ordering code if you are replacing an existing AF30-03 in a modular FRL set.

Spare parts for the AF30-D

• Filter element: AF30P-060S
• Baffle: AF34P-040S
• Bowl seal: C32FP-260S
• Polycarbonate bowl assembly with drain cock and bowl guard: C3SF-D
• Auto drain bowl assemblies: AD37-D (N.C.), AD38-D (N.O.)

Installation & maintenance

• Mount the AF30-03-D with the bowl vertical and pointing downward, with flow in the direction of the arrow.
• When refitting the bowl on the AF30-D, line up the lock button with the groove on the front or back of the body, so the bowl cannot drop or be damaged.
• Replace the element every 2 years, or when the pressure drop reaches 0.1 MPa, whichever comes first, to prevent damage to the element.
• Use a model with an element service indicator (L) where the filter is hard to inspect. Replace the element before the red band reaches the top of the indicator. The indicator may operate with a new element if the pressure differential exceeds 0.025 MPa.
• Keep polycarbonate bowls away from the solvents, chemicals and synthetic oils listed in the catalogue chemical data. Choose a metal or nylon bowl where such exposure is possible.
• Leave enough space below the bowl to remove it for maintenance.

Typical applications in Oman & the GCC

An AF30 body with 3/8 ports suits branch lines that feed individual machines, which is where most FRL sets are installed. Typical users include packaging and bottling lines in Muscat and Sohar, workshop and maintenance air in oil and gas service bases, pneumatic actuator panels in water and desalination plants, and food processing equipment. The humid coastal climate of the GCC means compressed air often carries a lot of condensate, so a float-type auto drain (C or D) is a sensible choice wherever the filter is not checked every day. Fitting an AF30-03-D upstream of an AR regulator and, where needed, an AFM mist separator protects the solenoid valves and cylinders further down the line.

Why source from Seven Star LLC

Seven Star LLC supplies SMC air preparation equipment across Oman and the GCC, including AF filters, AR regulators, AL lubricators and AFM/AFD mist separators. Send us your existing AF30-03 code or nameplate photo and request a quote. Our team can help confirm the correct ordering code for the -D successor, including thread, bowl, drain and bracket options.