Airtac PSS Exhaust Throttle Type Universal Speed Control Valve PSS1204B
The AirTAC Airtac PSS Exhaust Throttle Type Universal Speed Control Valve PSS1204B is a genuine universal speed controller with knob with aluminium-alloy locking cap and 360 degree adjustable tube direction, used to set the speed of a pneumatic cylinder by throttling its air.
- TypeUniversal speed controller
- SeriesPSS
- 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 PSS Exhaust Throttle Type Universal Speed Control Valve PSS1204B
The PSS1204B is a universal speed controller that sets the stroke speed of a pneumatic actuator by throttling air in one direction while letting it pass freely in the other. The B suffix marks it as a meter-in type: air from the 1/2in PT thread port flows to the Dia 12 tube without restriction, and flow in the reverse direction is throttled. AirTAC's own guidance treats meter-out as the first choice for double-acting cylinders driven by a solenoid valve, because exhaust throttling builds a back-pressure cushion. This B version is the pick for single-acting cylinders, where supply-side throttling avoids the stick-slip that plagues meter-in control on double-acting actuators under varying load.
Adjustment is by a knob with an aluminium-alloy locking cap, so a set speed stays set on a vibrating machine. The body combines brass and PBT plastic, and unlike the fixed-tube PSL, this universal version lets the tube swivel a full 360 degrees, so you can orient the run after installation without re-plumbing. The thread is PT standard and the tube end takes 12mm outside-diameter soft nylon or polyurethane tubing. A D suffix code would be the same part in black; the standard finish is grey.
Airtac PSS Exhaust Throttle Type Universal Speed Control Valve PSS1204B Technical Specifications
| Model | Airtac PSS Exhaust Throttle Type Universal Speed Control Valve PSS1204B |
|---|---|
| Type | Universal speed controller |
| Series | PSS |
| Adjustment | Knob with aluminium-alloy locking cap |
| Orientation | 360 degree adjustable 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 PSS Exhaust Throttle Type Universal Speed Control Valve PSS1204B
| PSS | Universal speed controller. |
|---|---|
| 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 PSS Exhaust Throttle Type Universal Speed Control Valve PSS1204B Is Used
Spring-return clamp on a blister packaging line
A single-acting spring-return clamp lowering onto a formed blister needs a gentle, metered close so the seal is not crushed. Supply-side meter-in through the PSS1204B gives the operator a repeatable close speed, locked by the cap.
Gravity-down heat-seal press head
On a semi-automatic bag sealer where the head descends under single-acting air and returns by spring, a meter-in controller at the cylinder port damps the drop and lets the cycle be timed to operator loading.
Pneumatic hold-down on a timber clamp carrier
Single-acting hold-down rams on a woodworking clamp carrier must press glued joints firmly but not slam. The 12mm bore carries the volume larger rams demand, and the swivelling tube end clears rotating carrier frames.
Is the Airtac PSS Exhaust Throttle Type Universal Speed Control Valve PSS1204B the Right Part?
Meter-out (A) versus meter-in (B): choose B for single-acting cylinders - spring-return clamps, diaphragm actuators, gravity-down presses - where throttling the supply gives a controlled stroke and the spring or load handles the return. If your actuator is double-acting and driven by a solenoid valve, step to PSS1204A instead, because meter-out exhaust throttling keeps the stroke smooth. Knob-and-locking-cap adjustment suits settings that are tuned once; if operators re-set speeds daily, a push-lock PTL cap resists accidental knocks better.
Sizing both ways on this ladder: one step down in tube is PSS1003B, Dia 10 with a 3/8in thread, which suits lighter duty lines and smaller ports; there is no step up in tube, because Dia 12 is the largest bore AirTAC lists on the 1/2in PSS. If your port is 3/8in rather than 1/2in, the same Dia 12 tube exists as PSS1203B. Whichever size you pick, mount 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 PSS Exhaust Throttle Type Universal Speed Control Valve PSS1204B FAQ
Working pressure 0-1.0 MPa (0-10 kgf/cm2), usable under vacuum to -750 mmHg (10 Torr), proof pressure 1.5 MPa, operating temperature -20 to +70 C. This SKU is the Dia 12 tube size with a 1/2in PT thread, in the universal body whose tube end swivels 360 degrees. Control method is B, meter-in. Applicable tubing is soft nylon or polyurethane.
A speed controller throttles; it is not a shut-off valve. Even fully closed it is designed to leak slightly, so never rely on it to isolate a circuit - that job belongs to a shut-off valve such as AirTAC's PHV finger valve. Also note AirTAC publishes capacity for the PSS range as characteristic curves rather than a single Cv or L/min figure, so compare sizes by tube bore and the curve, not a headline flow number.
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