Airtac PSL Throttle Speed Control Fitting PSL401B
The AirTAC Airtac PSL Throttle Speed Control Fitting PSL401B is a genuine speed controller, threaded elbow with knob with aluminium-alloy locking cap and fixed tube direction, used to set the speed of a pneumatic cylinder by throttling its air.
- TypeSpeed controller, threaded elbow
- SeriesPSL
- Working pressure0 - 1.0 MPa (0 - 10 kgf/cm2)
- Proof pressure1.5 MPa
- AdjustmentKnob with aluminium-alloy locking cap
- Temperature-20 to +70 °C
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac PSL Throttle Speed Control Fitting PSL401B
The PSL401B is a fixed-direction speed controller with a Dia 4mm one-touch tube outlet and a 1/8in PT male thread. It sets actuator speed by throttling air in one direction only: on this B-suffix (meter-in) code, flow from the thread port to the tube runs completely free, while the return path is throttled. That pairing is what AirTAC recommends for single-acting cylinders, where supply-side throttling gives a controlled stroke without the stick-slip that meter-in causes on double-acting actuators.
Adjustment is a hand knob on top with an aluminium locking cap: set the speed, then screw the cap down so vibration cannot walk the setting off. The body and throttling column are brass with PBT plastic for the holder, and the tube outlet is fixed - it does not swivel like the PSS universal version, which is worth remembering if your routing needs to rotate. Note this part is not a shut-off valve; a speed controller deliberately passes a small leak when fully closed.
Airtac PSL Throttle Speed Control Fitting PSL401B Technical Specifications
| Model | Airtac PSL Throttle Speed Control Fitting PSL401B |
|---|---|
| Type | Speed controller, threaded elbow |
| Series | PSL |
| Adjustment | Knob with aluminium-alloy locking cap |
| Orientation | Fixed tube direction |
| Working pressure | 0 - 1.0 MPa (0 - 10 kgf/cm2) |
|---|---|
| Negative pressure | -750 mmHg (10 Torr) |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Applicable tubing | Soft nylon or polyurethane tube |
| Thread standard | PT (Rc tapered) unless the code says otherwise |
POM release button and chuck, aluminium-alloy guide, stainless spring gasket, NBR O-ring; body brass or PBT depending on the part. A speed controller is not a shut-off valve - a small leak past a fully closed needle is normal. Close it before applying air, and turn it open slowly. AirTAC publishes flow as a characteristic curve rather than a single figure, so no L/min value is listed.
Model Code: Airtac PSL Throttle Speed Control Fitting PSL401B
| PSL | Speed controller, threaded elbow. |
|---|---|
| 4 / 6 / 8 / 10 / 12 | Tube outside diameter in mm (3.2 mm exists on the mini series). |
| M5 / 01 / 02 / 03 / 04 | Thread: M5x0.8, 1/8", 1/4", 3/8", 1/2" (M3 on the mini series). |
| A / B | A = meter-out (controls flow from the thread port to the tube). B = meter-in. |
| D | Black. Blank = grey. |
Meter-Out or Meter-In?
- check Meter-out (A) is the default. It throttles the air LEAVING the cylinder, so the piston runs against a back-pressure cushion and moves smoothly.
- check Use meter-out on double-acting cylinders - it is the one AirTAC lists as first priority.
- check Meter-in (B) throttles air ENTERING the cylinder. It suits single-acting cylinders and air motors.
- check Meter-in on a double-acting cylinder tends to give a jerky, stick-slip stroke under varying load.
- check Fit the controller at the cylinder port, not at the valve, so the throttled volume is as small as possible.
Where the Airtac PSL Throttle Speed Control Fitting PSL401B Is Used
Laboratory dosing ram
A spring-return dosing cylinder on a benchtop filling rig needs a gentle, repeatable downstroke. Meter-in throttling on the PSL401B controls the supply side, and the Dia 4mm bore suits the short strokes of small-bore lab actuators.
PCB test fixture clamp
A small single-acting paddle clamps a circuit board during electrical test. The locking cap holds the tuned closing speed against the constant vibration of a nearby compressor, so the clamp lands the same way every cycle.
Packaging guide-pin retract
On a carton-sealing station, a guide pin must retract slowly so film does not snag. Mounted at the cylinder port with its 1/8in PT thread, this controller meters the air feeding the pin and keeps retraction clear of the seal cycle.
Is the Airtac PSL Throttle Speed Control Fitting PSL401B the Right Part?
Meter-in (B) is the right pick when your actuator is single-acting - a spring-return clamp, a small ram or an air table. If you are driving a double-acting cylinder, choose the A suffix instead: throttling the exhaust creates a back-pressure cushion that keeps the stroke smooth under varying load. You cannot convert this unit between A and B in the field; the internal throttling column is handed, so order the suffix you need.
On sizing, Dia 4 is the smallest tube PSL offers on a 1/8in thread, so the only step up is the PSL601B with its Dia 6 bore - a real capacity jump for feeding short, fast strokes. The only thread below 1/8in in the Dia 4 ladder is M5, which suits compact valve manifolds; stepping to a 1/4in thread means moving up to a Dia 6 tube as well. Whatever you pick, screw the controller directly into the cylinder port so the throttled air volume stays small and response stays crisp.
Quick checklist
- ✓ Tube outside diameter matches exactly
- ✓ Thread size and standard match the port
- ✓ Working pressure within 0 - 1.0 MPa (0 - 10 kgf/cm2)
- ✓ Temperature within -20 to +70 °C
- ✓ Meter-out (A) unless you know you need meter-in
Airtac PSL Throttle Speed Control Fitting PSL401B FAQ
It is a meter-in (B) PSL speed controller with a Dia 4mm tube outlet and a 1/8in PT thread. Working pressure is 0-1.0 MPa (0-10 kgf/cm2), proof pressure 1.5 MPa, and it tolerates negative pressure down to -750 mmHg (10 Torr). Temperature range is -20 to +70 C. Standard colour is grey; add the D suffix for black. Wetted materials include a brass body and throttling column with PBT plastic holder and NBR seals.
No. A speed controller is designed to leak slightly when the knob is fully closed, so it must never be relied on to isolate a circuit. For a manual shut-off on Dia 4 to 12mm lines, use the AirTAC PHV finger valve - the PHV6A or PHV8A quarter-turn valve vents the outlet when closed, which also makes the downstream circuit safe to work on.
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