2KS Series Pilot-Operated Normally Open
When "Power-Off" Means "Flow-On": The Fail-Safe Open Logic of AirTAC 2KS Valves
In industrial automation, "Fail-Safe" is the cornerstone of risk management. For hazardous chemicals or fuel systems, fail-safe usually means Fail-Close (Normally Closed). But in critical cooling loops, fire suppression systems, or emergency pressure vents, a valve that closes upon power loss is the disaster itself.
The AirTAC 2KS Pilot-Operated, Normally Open (NO) series is engineered for the "reverse logic" applications where flow must be guaranteed. By defaulting to the OPEN position, this series provides the high-flow thermal and safety protection that million-dollar spindles, reactor jackets, and safety headers require.
- Fail-Safe Open Strategy: Default de-energized state is OPEN. Power is required only to actively stop the flow.
- High-Flow Pilot Design: Leverages system pressure to actuate large orifices (up to 50mm) with a tiny, cool-running coil.
- MOPD Efficiency: Requires a Minimum Operating Pressure Differential of 0.05 MPa (7.3 psi) to shift.
- Industrial Armor: SUS304 Stainless Steel body and FPM-F (Viton) seals as the factory standard for corrosive and high-purity media.
- Massive Scaling: Portfolio ranges from 1/2" (5.50 Cv) to 2" (49.00 Cv) main-line headers.
1. The Strategic Logic of "Normally Open"
Asset Protection
On a cooling circuit, the 2KS-NO ensures that even during a total plant blackout, coolant flow continues via thermal siphon or auxiliary headers, preventing warping or mechanical seizure.
Safety Venting
Used on pressure vessels where the "Safe State" is a vented, zero-energy state. If control power is severed, the valve springs open to prevent over-pressure explosion risk.
Thermal Efficiency
In constant-flow loops (On 99% of the time), the 2KS consumes zero power and generates zero heat, saving thousands of kilowatt-hours and extending coil life.
2. Engineering the "Pilot" Leverage
Moving a 50mm seal against 100 psi requires massive force. Direct-acting solenoids would require melon-sized coils for this task. The 2KS uses an Internally Piloted strategy: the coil only opens a microscopic pilot hole, using the fluid's own energy to move the main piston.
The MOPD Threshold
Because the valve uses system pressure as its "muscle," it requires a Minimum Operating Pressure Differential (MOPD) of 0.05 MPa (7.3 psi). If you attempt to use this series for gravity-fed tanks with zero head pressure, the pilot will fail to shift. For zero-pressure applications, you must specify a "Direct-Acting" series.
$$Force_{Actuation} = Pressure_{System} \times Area_{Piston}$$
3. Material Excellence: SUS304 + FPM-F
SUS304 Stainless Shield
Standard for food, pharma, and deionized water. It resists the "leaching" and corrosive pitting that destroys brass in high-purity or acidic water loops.
FPM-F (Viton) Performance
Offers elite resistance to oils, fuels, and mineral acids. Caution: Viton is incompatible with Acetone. For ketones, specialized seal variants must be requested.
4. Technical FAQ & Troubleshooting
1. "I energized the valve, but it won't close. Is it defective?"
99% of the time, the answer is pressure. If your line pressure is below the 7.3 psi MOPD threshold, the valve lacks the physical energy to shift the piston. Verify your gauges at the valve inlet.
2. "DIN (CDA) vs. Flying Leads (CLA) - which is better?"DIN is for maintenance. It allows for 1-minute, plug-and-play coil swaps. Flying leads are for high-vibration or permanent OEM wiring. For 90% of industrial facilities, DIN is the superior TCO investment.
Irreplaceable Safety Integrity
The AirTAC 2KS Normally Open series is a critical safety device disguised as a process valve. By embracing a "Fail-Safe Open" philosophy and leveraging smart pilot physics to control massive 49.0 Cv flows, it ensures your lifelines stay active even in the darkest power loss scenarios. It is the definitive guardian for high-flow cooling, safety venting, and emergency fluid supply.