Airtac M5L One-way Roller Lever Type Mechanical Valve M5L21008G
Mechanically actuated · no coil, no pilot airThe AirTAC Airtac M5L One-way Roller Lever Type Mechanical Valve M5L21008G is a genuine 5/2-way roller, free-return type control valve. A one-way roller. It switches on the return pass only and idles in the other direction. It is an external control, direct-acting valve - the spool is moved mechanically, so there is nothing to wire and no pilot line to plumb. Ports are PT1/4 with a 12.0 mm2 (Cv 0.67) effective area.
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Specifications
| Model | M5L21008G |
|---|---|
| Valve type | 5/2 way, external control, direct acting |
| Actuation | Roller, free-return type |
| Reset | Automatic (spring) restoration |
| Body series | 200 Series, single control |
| Port size | PT1/4 |
| Effective area | 12.0 mm2 (Cv 0.67) |
| Button colour | Green |
| Fluid | Air, filtered by a 40 um element |
|---|---|
| Pressure range | 0 - 1.0 MPa (0 - 145 psi) |
| Proof pressure | 1.5 MPa (215 psi) |
| Temperature | -20 to +70 C |
| Body material | Aluminium alloy |
| Lubrication | Not required |
| Thread standard | G (BSPP parallel) |
| Spool stroke | 2.0-3.0 mm |
| Actuator stroke | 5.0-7.8 mm at the roller |
Sliding-column (spool) construction, so operating force is not affected by working pressure - there is no back-pressure effect. Lubrication is not required, but once the valve has been run on lubricated air it must stay on lubricated air; AirTAC suggests ISO VG32 or equivalent. The roller, free-return type control set is METAL, which gives a longer service life than the engineering-plastic heads. The exhaust outlet sits on top of the body, so a silencer fits directly.
About the M5L21008G
The AirTAC M5L21008G is a 5/2 way external control, direct acting valve with no coil and no pilot port: the spool is thrown mechanically by a passing machine part striking its roller. The L actuator is the one-directional member of the roller pair - it trips on impact travelling right to left only, and the reverse direction is deliberately invalid, which is what lets you switch a signal on the return pass of a stroke while ignoring the forward pass. The roller carries the spool back as it leaves, so there is no spring to fatigue and no holding state to reset.
This is the 210 body with a G1/4 port and an effective area of 12.0 mm2 (Cv 0.67), the largest flow rating in the M5 common-type range. The sliding-column construction means the changeover force is not affected by working pressure, so switching behaviour stays consistent from zero up to 1.0 MPa. The L control set is metal for long service life, the exhaust sits on top of the body so a silencer screws straight on, and the valve supports both body and panel mounting. Spare control sets can be ordered separately if a roller ever needs replacing.
Typical applications
Press return-pass ejection
Mount the valve at the rear of a pneumatic press bed so the ram carriage trips the roller only on its right-to-left return stroke, sending an air signal to eject the formed part after forming is complete, while the forming stroke itself passes unheeded.
One-way pallet divert gate
Fit the roller beside a conveyor lane so pallets travelling in the permitted direction flick the valve and open a divert gate, yet a pallet nudged or rolled backwards cannot retrigger it, giving an inherently directional interlock with no electrical sensing.
Clamp table retract signal
Position the valve so the moving clamp rail strikes it at the end of the unclamping travel, feeding a signal that starts the next slide or table motion - sequencing a two-axis fixture purely with air, triggered only when the clamp retracts in the correct direction.
How to choose
Choose between L and R on direction, not on anything else. The R roller responds to a cam passing in either direction, so it fires on every pass of the carriage; this L valve fires only when the cam travels right to left, which is exactly what you want when the forward pass must be ignored and a signal must start on the return. If you need the valve to hold its position after tripping, step up to a manually restored actuator such as Y or HS instead - a roller valve always returns with the cam. The 210 body with the 1/4 inch port and 12.0 mm2 orifice suits cylinders in the mid-to-large range; drop to the 110 body or the 1/8 inch port for smaller bores. Critical fitting note: the cam must engage within this model's reversal stroke - 2.0 to 3.0 mm of spool movement and 5.0 to 7.8 mm of roller travel - because exceeding those limits will damage the valve.
Frequently asked questions
It is a 5/2 way external control, direct acting mechanical valve (roller, free-return, one-directional). Working pressure is 0-1.0 MPa (0-145 psi) with a proof pressure of 1.5 MPa (215 psi); operating temperature is -20 to +70 C. The port is G1/4 on the 210 body, with an effective area of 12.0 mm2 (Cv 0.67). Fluid is air filtered by a 40 um element, the aluminium alloy body needs no lubrication, and the metal control set is available as a spare.
The valve is damaged - the datasheet states this explicitly. Stay within the published reversal stroke: 2.0 to 3.0 mm of spool movement and 5.0 to 7.8 mm of roller travel for this L type. Profile the cam or striker so contact is fully taken up inside that window and never bottoms out, and set the roller plane so the carriage crosses it squarely rather than driving past the end of travel.