Airtac M5L One-way Roller Lever Type Mechanical Valve M5L21008
Mechanically actuated · no coil, no pilot airThe AirTAC Airtac M5L One-way Roller Lever Type Mechanical Valve M5L21008 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 | M5L21008 |
|---|---|
| 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) |
| 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 | PT (Rc tapered) |
| 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 M5L21008
The AirTAC M5L21008 is a 5/2 way external control, direct acting valve that is thrown mechanically by a roller lever - there is no coil, no pilot port and no wiring of any kind. It is the free-return roller version of the M5 family: a passing cam or carriage trips it on one travel direction only (impact right to left), and the opposite direction is deliberately invalid by design, not a defect. That makes it the natural choice when a signal must fire on the return pass of a stroke and stay silent on the approach pass.
This example uses the 200 Series single control body (the 210 in the code) with a 1/4 inch PT port, giving an effective area of 12.0 mm2 (Cv 0.67), the largest flow rating in the M5 range. The metal control set gives longer, more stable service than the plastic sets used on the manual button variants, and the sliding spool construction means the control force is unaffected by working pressure - there is no back-pressure effect, so changeover feels identical from 0 to 1.0 MPa. The exhaust sits on top of the body, so a silencer screws straight in without re-plumbing.
Typical applications
Return-pass signal on a chain conveyor
Mount the roller so pallets or fixtures trip it moving right to left only. The reverse run of the chain passes the roller without switching, so downstream cylinders stay parked until the fixture comes back.
Retract-confirm on a drilling slide
Fit the M5L21008 at the rear limit of a pneumatic drill slide. The slide trips it on the retract stroke, confirming full return before the next drill cycle starts - and the forward pass cannot false-fire the signal.
Gate interlock on a carton divert
On a packaging line, trip the valve as the rejection arm swings back on its return sweep, venting and resetting the divert cylinder so the gate is always home before the next carton arrives.
How to choose
Choose between the two roller versions by direction of travel: the M5R trips from either side and signals on both passes of the machine cycle, while this M5L only accepts impact travelling right to left and ignores the opposite direction, so it switches the return pass exclusively and cannot false-trigger on the approach. If you need an operator to hold the state, that is a different actuator entirely - the M5Y lever or M5HS selector stay where they are set, whereas this roller resets itself the moment the cam moves off.
The 210 body with a 1/4 inch port carries 12.0 mm2 (Cv 0.67) against 9.0 mm2 (Cv 0.50) on the same body in 1/8 inch, so step up to this port when feeding a larger bore cylinder. Respect the reversal stroke limits: the spool needs 2.0-3.0 mm of travel and the roller actuator 5.0-7.8 mm. Exceeding these figures damages the valve - AirTAC states this explicitly - so profile your cam so it cannot over-travel the roller at either end.
Frequently asked questions
It is a 5/2 way external control, direct acting, mechanically actuated valve with a PT 1/4 inch port and an effective area of 12.0 mm2 (Cv 0.67). Operating pressure is 0-1.0 MPa (0-145 psi) with a proof pressure of 1.5 MPa (215 psi), and the working temperature range is -20 to +70 C. The medium is air filtered by a 40 um element, the body is aluminium alloy, lubrication is not required, and the metal roller control set is one of the long-life metal variants in the family.
The published reversal stroke for the M5L is 2.0-3.0 mm at the spool and 5.0-7.8 mm at the roller actuator. AirTAC states explicitly that exceeding these limits damages the valve, so design your cam or trip dog to complete the switch inside that window and clear the roller completely on the invalid direction of travel. Also note the one-way behaviour is intentional: the valve will not switch when impact arrives from the opposite side, so it must be oriented for right-to-left tripping at installation.