Airtac PSL Throttle Speed Control Fitting PSL1204B-S
SUS304 stainless variant (-S)The AirTAC Airtac PSL Throttle Speed Control Fitting PSL1204B-S 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-S
The PSL1204B-S is AirTAC's largest standard-thread inline speed controller built for corrosive duty. It throttles air in one direction while letting it pass freely in the other, so an actuator's stroke can be timed precisely. The -B suffix marks meter-in control: flow from the 1/2in PT thread port into the Dia 12 tube runs free, while the return path is throttled. Fit it in the supply line to a single-acting cylinder or spring-return actuator and the handle marked B sets how fast air fills the chamber.
As a PSL body, the tube connector points in one fixed direction; if you need a swivelling outlet on this bore, the PSS stainless ladder carries it instead. The SUS304 build replaces the brass throttling column of the standard PSL with stainless steel, and the spring gasket is stainless too - the pressure, temperature and fitting dimensions are identical to the standard part. Adjust by turning the aluminium-alloy cap with its locking collar, then lock the setting against vibration.
Airtac PSL Throttle Speed Control Fitting PSL1204B-S Technical Specifications
| Model | Airtac PSL Throttle Speed Control Fitting PSL1204B-S |
|---|---|
| Type | Speed controller, threaded elbow |
| Series | PSL |
| Adjustment | Knob with aluminium-alloy locking cap |
| Orientation | Fixed tube direction |
| Body material | Stainless steel 304 (-S variant) |
| 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. Stainless (-S): SUS304 throttling column and body parts in place of brass, for copper-free environments. Ratings are unchanged from the standard version. 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-S
| 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. |
| -S | Stainless-steel body. |
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-S Is Used
Marine deck hatch actuator
A single-acting ram closing a wheelhouse hatch on a workboat sees salt spray and washdown. The SUS304 throttling column resists seawater corrosion, and the B handle lets the crew set a controlled, quiet close from the supply side.
Chemical dosing line take-off
Feeding a single-acting diaphragm pump pilot from a 1/2in PT branch, the meter-in control meters the air filling the chamber. Stainless internals avoid copper carry-over into aggressive media where brass would degrade.
Brine tank lid clamp in food washdown
A spring-return clamp arm lowering onto a brine tank lid must not crash onto the rim. Meter-in throttling cushions the power stroke, and the stainless body shrugs off daily caustic hose-down on the CIP line.
Is the Airtac PSL Throttle Speed Control Fitting PSL1204B-S the Right Part?
Meter-in is the right choice when the actuator is single-acting or spring-return: throttling the supply gives a predictable stroke. Do not specify meter-in to slow a double-acting cylinder under varying load - throttled supply on a double-acting circuit invites stick-slip, and AirTAC lists meter-out as the first-priority method. If your circuit is double-acting, pick the -A variant of this code instead.
Sizing: on the 1/2in PSL ladder the neighbours are Dia 10 (PSL1004B-S) below and nothing above - Dia 12 is the largest tube this thread takes. Stepping down to Dia 10 reduces the bore feeding the actuator, which trims the free-flow capacity and the fitting footprint. Dia 12 is also offered on the 3/8in thread if your porting is smaller. Whichever you choose, install the controller directly at 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 PSL1204B-S FAQ
Working pressure 0-1.0 MPa (0-10 kgf/cm2), proof pressure 1.5 MPa, vacuum to -750 mmHg (10 Torr), ambient and media temperature -20 to +70 C. This SKU is the Dia 12 tube size with a 1/2in PT male thread, SUS304 stainless construction, meter-in (B) control. The stainless build changes the throttling column and spring gasket material only - every pressure and temperature figure matches the standard PSL1204B.
It is not a shut-off valve: like every speed controller in this family it leaks slightly when fully closed, so use a separate stop valve to isolate the circuit. The B meter-in setting suits single-acting and spring-return actuators, where throttling the supply air gives a smooth controlled stroke; on a double-acting cylinder it can cause stick-slip, so choose the A meter-out version there.
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