Pneumatic Vacuum Butterfly Valves
DELCO Pneumatic Vacuum Butterfly Valves are specially engineered to maintain a tight seal under negative pressure. These air-driven valves prevent air leakage into the system, ensuring reliable performance in vacuum drying and coating processes.
Pneumatic Vacuum Butterfly Valve: Rapid Pump-Down & High-Vacuum Isolation
Engineered for semiconductor manufacturing tools, vacuum coating systems (PVD/CVD), industrial freeze dryers, and vacuum heat treatment furnaces, the Delco pneumatic butterfly valve vacuum series delivers reliable isolation across the vacuum spectrum from roughing pressure down to high vacuum (1.3 × 10-5 Pa / 10-7 mbar). Utilizing specialized low-outgassing fluoroelastomer O-ring seats, mirror-finished 304/316L stainless bodies, and sub-second pneumatic actuation, these valves prevent atmospheric ingress and ensure particle-free chamber cycling.
Technical Merits: High-Vacuum Sealing & Rapid Automation
Precision dovetail O-ring grooves and micro-machined disc sealing faces ensure leak-tight performance from positive atmospheric pressure down to 1.3 × 10-5 Pa.
High-grade Viton (FKM) and optional perfluoroelastomer (FFKM) seals are vacuum-degassed and post-baked, minimizing hydrocarbon outgassing and chamber contamination.
Direct single-acting pneumatic actuators trigger in under 300 milliseconds upon air or power interruption, instantly isolating the high-vacuum process chamber from oil backstreaming.
Rotary stem features dual precision Viton O-rings with an intermediate pumpable vacuum buffer zone, completely stopping atmospheric gas permeation along the shaft axis.
Cleaned via multi-stage ultrasonic degreasing, assembled in Class 10,000 cleanroom environments, and double-sealed in anti-static PE bags to protect high-purity semiconductor tools.
The slim aerodynamic disc design provides maximum conductance in the open position, drastically reducing chamber pump-down evacuation cycles and increasing system throughput.
Vacuum Butterfly Valve Specifications Matrix
| Parameter | ISO-KF Quick Flange | ISO-K / ISO-F Large Bore | CF Ultra-High Vacuum |
|---|---|---|---|
| Flange Size Range | KF16, KF25, KF40, KF50 | ISO63, ISO100, ISO160, ISO200, ISO250 | CF35, CF63, CF100, CF150 |
| Pressure Operating Range | 1 × 105 Pa to 1.3 × 10-4 Pa | 1 × 105 Pa to 1.3 × 10-5 Pa | 1 × 105 Pa to 1.3 × 10-6 Pa |
| Body Construction | AISI 304 Stainless / Aluminum Alloy | AISI 304 / 316L Stainless Steel | Forged AISI 316L (Electropolished) |
| Disc Sealing Material | Vacuum-Grade Viton (FKM) | Viton (FKM) / Silicone | Low-Outgassing FFKM (Kalrez) |
| Helium Leak Rate | < 1.0 × 10-9 Pa·m³/s | < 1.0 × 10-9 Pa·m³/s | < 1.0 × 10-10 Pa·m³/s |
| Bakeout Temperature | Up to 120°C (Actuator detached) | Up to 150°C (Actuator detached) | Up to 200°C (Actuator detached) |
| Pneumatic Actuation | Double-Acting (DA) or Single-Acting Spring-Return (SR Fail-Closed); Actuation Air 0.4 – 0.6 MPa | ||
| Vacuum Position Feedback | Cleanroom-compatible magnetic reed switches or contactless inductive proximity sensors (PNP/NPN) | ||
Frequently Asked Questions: Vacuum Butterfly Valves
Q1: Why are butterfly valves used instead of gate valves on vacuum forelines?
While vacuum gate valves offer zero obstruction, they are expensive, heavy, and have long stroke travel. Vacuum butterfly valves have an ultra-thin profile, low internal volume, and cycle in under 0.3 seconds at a fraction of the cost, making them the superior engineering choice for roughing pump lines and fast bypass lines.
Q2: How does the valve achieve a helium leak rate below 10-9 Pa·m³/s?
Achieving high vacuum tightness requires strict metallurgical control. Delco utilizes forged 304/316L stainless steel bodies free of microscopic casting porosity, precision-machined trapezoidal O-ring retaining grooves that eliminate micro-voids, and vacuum-degassed fluoroelastomer seals with ultra-fine contact surface finishes.
Q3: What fail-safe protection occurs if electrical power or shop air is cut?
Single-acting Spring-Return (SR) actuators are standard for vacuum safety isolation. If compressed air fails or an electrical trip occurs, internal mechanical springs immediately snap the valve into the closed position in < 0.2 seconds, preventing mechanical pump oil backstreaming or atmospheric venting into the vacuum chamber.
Q4: Can these vacuum butterfly valves be baked out during chamber degassing?
Yes. The stainless steel valve body and Viton seals can withstand system bakeout temperatures up to 150°C (up to 200°C when equipped with FFKM seals). The pneumatic actuator is mounted with thermal decoupling standoffs, or can be quickly unbolted via its ISO 5211 interface during high-temperature chamber bake cycles.
Direct Factory Supply: High-Vacuum Pneumatic Butterfly Valves
Precision stainless steel vacuum butterfly valves with KF, ISO, and CF flanges. 100% helium mass-spectrometer leak tested, assembled in cleanroom conditions, and pre-fitted with fast-acting pneumatic actuators for high-vacuum chamber integration.