SMC AL30-03 Modular Lubricator 3/8 Rc

Adding oil mist to the air where it is needed

AL30-03 is the size 30, Rc 3/8 modular lubricator of the SMC AL series. It meters a fine mist of turbine oil into the air stream so that tools, rotary actuators and cylinders that need lubricated air receive a steady supply, and it is the last block of the classic filter, regulator and lubricator chain. Modern non-lube cylinders and valves do not need it (the SMC cylinder and valve catalogues commonly state that lubrication is not required), so fit a lubricator only where the equipment calls for it.

The code AL30-03 gives the series and body size (AL30) and the port (03 is 3/8). With no letters after 03 it has Rc threads, a polycarbonate bowl, no bracket and left-to-right flow. Letters in the how-to-order table add a bracket (B), other threads and bowl options.

Technical specifications

What the minimum dripping flow means

The lubricator only begins to feed oil when the air flow exceeds a threshold. The catalogue defines the minimum dripping flow as the air consumption at which five or more drips per minute occur with an inlet pressure of 0.5 MPa, turbine oil ISO VG32, 20 deg C and the oil adjustment valve fully open. For the 3/8 AL30 that is 40 L/min (ANR); a circuit with a lower average flow will not receive oil, so the lubricator should be placed on a line with enough consumption.

The practical conclusion is that one AL30 on the main supply of a machine with many small intermittent loads may not meter oil evenly. For such cases lubricate with a smaller AL20-D (minimum dripping flow 15 L/min (ANR)) closer to the load, or use a different method.

Use, caution and compatibility

Use only the lubricant the catalogue names, a class 1 turbine oil to ISO VG32, with no additives that could harm the polycarbonate bowl; refer to the chemical data in the catalogue when selecting the bowl material. As general practice, once a component has been run on lubricated air its factory grease may be washed out, so it is best to keep lubricating that line. Install the lubricator downstream of the filter and regulator and above the equipment where practicable, so oil mist does not collect in low pipework.

Keep the bowl out of strong sunlight and check the oil level routinely through the transparent bowl.

Documents and quotation

The SMC AL catalogue linked at the end of this page covers the order codes, specifications, options and dimensions for the current AL20-D to AL60-D range. Please confirm thread, bowl and bracket before ordering. More air-preparation items can be found under Regulators. Seven Star LLC is an independent supplier and quotes the exact code on request.

AL30-03 and its current successor, AL30-03-D

AL30-03 is the code from the earlier generation of SMC modular lubricators. SMC has superseded it with the -D series, and the current equivalent is AL30-03-D. The product photo and the official catalogue linked at the end of this page show the -D version. The body size, Rc 3/8 port, ISO VG32 turbine oil recommendation and 40 L/min (ANR) minimum dripping flow at 3/8 port size are the same, so an AL30-03-D is the normal replacement for an existing AL30-03. On the AL30-D, a transparent polycarbonate bowl guard is standard, the oil capacity is 55 cm3, and the bowl has a lock button that must line up with the groove in the body. Bowl, bracket and spare part numbers follow the -D catalogue.

How the AL30-03 lubricator works

Air flowing through the body passes a damper, a flexible flow-sensing element that creates a small pressure difference proportional to the flow. This pressure difference lifts oil from the bowl up a siphon tube into the sight dome. There it drips at a rate set by the oil regulating valve, and each drop is atomised by the high-velocity air and carried downstream as a fine mist. Because the pressure difference depends on flow, the AL30 feeds more oil when the air demand is higher. This is also why there is a minimum dripping flow, below which no oil is fed. SMC rates this as 5 drops or more per minute at 0.5 MPa inlet pressure and 20 °C, with ISO VG32 oil and the valve fully open.

For circuits that repeatedly switch ON and OFF on the outlet side, SMC advises adjusting so that the average air consumption per minute is at least the minimum dripping flow rate.

Selection & ordering guide for AL30-03-D

The catalogue example AL30-F03B-3RW-D is a G 3/8 lubricator with a bracket, a drain cock, right-to-left flow and a barb fitting on the drain cock. The barb-fitting drain cock (3W) cannot be combined with the metal bowls 2 and 8. Our team can help confirm the correct ordering code when you are matching an AL30-03 in an existing modular set.

Spare parts for the AL30-D

• Lubrication plug assembly: AL34P-060AS
• Damper retainer assembly: AL30P-030AS
• Damper assembly: AL30P-040S
• Bowl seal: C32FP-260S
• Polycarbonate bowl assembly with bowl guard: C3SL-D (C3SL-3-D with drain cock)

Installation & maintenance

• Install the AL30-03-D downstream of the filter and regulator, with the bowl vertical and flow in the direction of the arrow.
• If the piping branches on the inlet side of the lubricator, install a check valve to stop lubricant flowing backwards.
• Adjust the oil regulating valve on the sight dome by hand only. Turning it counterclockwise increases the dripping amount, and clockwise reduces it. From fully closed, three turns bring it to fully open; do not turn it further. The numbered scale is a position guide, not a measure of the drip rate.
• Tighten the lubrication plug on the AL30-D to 0.35–0.45 N·m. Under-tightening can cause leaks, and over-tightening can damage the thread.
• When refitting the bowl, line up the lock button with the groove in the body.
• Use Class 1 turbine oil (ISO VG32) only, and check the oil level regularly.

Typical applications in Oman & the GCC

Lubricated air is still needed by many air tools, older pneumatic cylinders and valves, air motors and some rotary actuators. You will find them in fabrication shops, oilfield equipment workshops, port and marine maintenance yards, and older production lines across Oman and the GCC. An AL30-03-D at the end of an AF/AR modular set feeds a steady oil mist to such equipment. Where a line also supplies non-lube valves, instruments or breathing air, take that branch off upstream of the lubricator.

Why source from Seven Star LLC

Seven Star LLC supplies SMC modular air preparation units across Oman and the GCC, including AL lubricators, AF filters, AR regulators and their brackets and spacers. Request a quote with your existing AL30-03 code. Our team can help confirm the correct ordering code for the -D successor, including bowl, drain cock and thread options.