2W Series Pilot-Operated Normally Closed Type
The Unassuming Workhorse: Why the AirTAC 2W Series is the Smartest Choice for Everyday Fluid Control
In machine design, engineers fight the tyranny of choice every day. When tasked with simply turning water, air, or oil on and off, the choice is polarizing. You face either expensive, over-designed stainless steel process valves or cheap, fragile plastic toys.
However, the vast majority of industrial applications—cooling loops, pneumatic presses, and lubrication systems—demand a reliable "workhorse." The AirTAC 2W Series Fluid Control Valve (including the 2W150, 2W200, and 2W250) is meticulously engineered to control the three most common industrial media—Water, Air, and Oil—with absolute reliability.
- "Leverage" Design: Uses an Internally Piloted mechanism to control massive flow (up to Cv 12.50) with a highly efficient 6.5W coil.
- The "Golden" Body: Constructed from industrial-standard Brass, offering optimal durability, heat resistance, and cost-effectiveness.
- Premium Seal Standard: FPM-F (Viton) seals come standard, solving the "rubber dilemma" with broad chemical compatibility and heat resistance.
- Fail-Safe Default: A 2/2-Way Normally Closed (NC) design ensures flow stops immediately if power is lost.
1. Core Value: The Genius of Pilot Operation
Opening a 25mm (1-inch) orifice against 150 psi of fluid pressure requires immense force. Using "direct action"—a magnet physically pulling the plug—would require a massive, power-hungry coil. The 2W series utilizes a smarter strategy: Indirect Acting (Internal Pilot).
The tiny 6.5W solenoid coil doesn't open the main valve; it only opens a microscopic pilot hole. This action dumps the pressure from the chamber above the main diaphragm. With the top pressure eliminated, the inlet fluid pressure pushes the main diaphragm up effortlessly. The valve uses the system's own hydraulic energy to open itself.
⚠️ The Trap: Minimum Pressure Requirement
Because this design relies on system pressure to actuate the main diaphragm, it requires a Minimum Pressure Differential of 0.05 MPa (10 psi). If your inlet pressure is only 3 psi (e.g., a gravity-fed drain), the pilot will click, but the main valve will fail to open. For zero-pressure or vacuum systems, you MUST specify a Direct-Acting valve (like the 2WA series).
Because this design relies on system pressure to actuate the main diaphragm, it requires a Minimum Pressure Differential of 0.05 MPa (10 psi). If your inlet pressure is only 3 psi (e.g., a gravity-fed drain), the pilot will click, but the main valve will fail to open. For zero-pressure or vacuum systems, you MUST specify a Direct-Acting valve (like the 2WA series).
2. Anatomy of Reliability: Built for Purpose
The Seal Decision: Why FPM-F (Viton) is Standard
Engineers often face a "Seal Dilemma": NBR (Buna) fails in high heat; EPDM is destroyed by oil. AirTAC's decision to make FPM-F (Viton) the standard seal resolves this. FPM-F is excellent for Oil AND Water, and withstands high temperatures (up to ~200°C). One SKU handles multiple media flawlessly, eliminating the risk of installing a water-only valve on an oil line.
3. Sizing for Flow: Cv Matters More Than Pipe Size
Do not simply match pipe threads; engineer the system based on the required Flow Coefficient (Cv):
- 2W150-15 (1/2"): Orifice 15mm. Cv = 5.50
- 2W200-20 (3/4"): Orifice 20mm. Cv = 9.50
- 2W250-25 (1"): Orifice 25mm. Cv = 12.50
The Sizing Trap: Oversizing
Installing a Cv 12.50 valve on a system that only requires Cv 5.0 is dangerous. When the oversized valve opens, a massive fluid surge causes "Water Hammer," triggering pressure spikes and violent valve chatter. Always calculate your required Cv and select the closest match.
Installing a Cv 12.50 valve on a system that only requires Cv 5.0 is dangerous. When the oversized valve opens, a massive fluid surge causes "Water Hammer," triggering pressure spikes and violent valve chatter. Always calculate your required Cv and select the closest match.
4. The Driving Force: Coils and Connections
For maximum reliability, specify DC Coils. AC coils are prone to 60Hz "Buzzing" and will suffer catastrophic burnout from continuous "Inrush Current" if debris prevents the plunger from seating. DC coils draw constant power (6.5W), run cooler, and will not burn out if the valve sticks.
Technical Troubleshooting FAQ
"My new 2W valve clicks but no fluid flows. Is it broken?"
No. You are likely testing it with near-zero pressure (e.g., gravity feed). The 2W is an internally piloted valve; it requires a minimum of 10 psi to push the main diaphragm open. The "click" confirms the pilot is working, but without system pressure, the main valve remains shut.
"Can I use this for Steam or strong Acids?"
NO. The brass body will rapidly corrode in acid. While the FPM seal handles heat well, steam requires specialized piston architectures. For steam or corrosive acids, you must specify the 2L Series (Stainless Steel + PTFE).
The Smart Default
The AirTAC 2W Series doesn't attempt to be the most exotic valve on the market. It is engineered to be the smartest, most practical "default option" for 80% of industrial fluid control tasks. By merging a highly efficient Pilot design, a robust Brass body, and the universal capability of an FPM-F seal, it delivers massive flow and steadfast reliability.