Airtac PSL Throttle Speed Control Fitting PSL1204B
The AirTAC Airtac PSL Throttle Speed Control Fitting PSL1204B 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 PSL1204B
The PSL1204B is a knob-adjusted speed controller that sits in a 1/2in PT port and grips Dia 12mm one-touch tubing. It throttles air in one direction and lets it pass freely in the other, which is how the stroke speed of a pneumatic actuator is set. This code carries the B suffix, so it is the meter-in version: air flowing from the thread port out through the tube runs at full bore, and the controlled direction is the return, tube back to thread. AirTAC marks the handle B so operators can confirm the control direction on the machine at a glance.
Meter-in control is the match for single-acting cylinders, where air on the supply side sets the pace and a spring returns the ram. On a double-acting cylinder it tends to stick-slip as the load changes, so for those circuits AirTAC recommends the A (meter-out) version instead. Adjustment is by a knurled knob under an aluminium locking cap - snug the cap down and vibration cannot walk the setting away. The body and throttling column are brass, the holder is PBT plastic and the seal is NBR. Note that a speed controller is not a shut-off valve; it weeps slightly when fully closed, so only the PHV finger valve should be used to isolate a circuit.
Airtac PSL Throttle Speed Control Fitting PSL1204B Technical Specifications
| Model | Airtac PSL Throttle Speed Control Fitting PSL1204B |
|---|---|
| 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 PSL1204B
| 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 PSL1204B Is Used
Scrap-bin compactor ram
A single-acting compactor ram in a fabrication shop pushes offcuts into a bin. Meter-in control on the supply side gives the operator a dial for ram pace, and the Dia 12mm bore feeds the volume a large cylinder needs without starving it.
Press fixture safety clamp
A large swing clamp on a welding press fixture must close onto a machined face without marking it. The B version slows the closing stroke of a spring-return cylinder while the locking cap holds the setting against press-floor vibration.
Trailer tailgate lift assist
A single-acting lift-assist cylinder on a delivery-truck tailgate is tuned so the gate descends in a controlled arc rather than dropping. The 1/2in PT port suits the heavier valves fitted to vehicle-mounted pneumatic systems.
Is the Airtac PSL Throttle Speed Control Fitting PSL1204B the Right Part?
You are at the top of the 1/2in ladder here: PSL is offered on 1/2in thread in Dia 8, 10 and 12, so the only step down is the PSL1004B on Dia 10mm tube - go that way if your cylinder port is a 1/2in but your air demand is modest and you want smaller tubing runs. There is no larger tube on this thread. If your tubing is already Dia 12mm but the port is 3/8in, the PSL1203B covers the same bore on the smaller thread; for Dia 12 tube you cannot go to M5, 1/8in or 1/4in on this prefix because those threads top out at smaller bores.
Compared with the swivelling PSS, the PSL body is fixed: once the nut is tightened the tube points one way, so plan the tubing route before you install. Fit the controller directly at the cylinder port rather than back at the valve manifold - the throttled air volume stays small and the speed response is far crisper. This large-bore size is aimed at actuators in the 100mm-plus bore class where a small restrictor would choke the flow curve badly.
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 PSL1204B FAQ
Working pressure 0-1.0 MPa (0-10 kgf/cm2), proof pressure 1.5 MPa, usable under vacuum to -750 mmHg (10 Torr), and an operating temperature range of -20 to +70 C. It takes Dia 12mm soft nylon or polyurethane tubing on a 1/2in PT male thread and is the B (meter-in) version with the handle marked B. Standard colour is grey; the D suffix orders the same part in black.
No. No speed controller in this catalogue has a built-in silencer and none is offered as an option - silencers are separate parts fitted at the valve exhaust port, not at the controller. Also remember this B version controls the return direction only: air from the 1/2in thread port out to the Dia 12mm tube passes unthrottled, so size your supply tubing for full flow.
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