ASCO™ 551 Series is a compact, high-performance solenoid spool valve engineered for reliable directional control of air and inert gases in demanding industrial environments. It masterfully combines a hard T-seal with a flexible O-ring to ensure bubble-tight sealing, resistance to dirt, and long-term reliability for millions of cycles.
The valve’s intelligent design allows it to be configured for both 3/2 NC and 5/2 way functions, making it a versatile choice for controlling single-acting or double-acting pneumatic actuators. Designed for direct mounting on actuators with NAMUR interfaces per VDI/VDE 3845 standard or as an in-line valve, it is the ideal solution for compact system designs.
Built to withstand challenging conditions, the 551 Series features a robust enclosure that provides environmental protection (IP65/IP67) against liquids and dust. It is backed by a comprehensive suite of global explosion-proof certifications (ATEX, IECEx, NEPSI, UL, CSA) for safe operation in hazardous locations, making it a trusted component in mission-critical applications worldwide.
Superior Reliability & Long Life: Features a unique seal design for bubble-tight shut-off and durability exceeding 5 million cycles, ensuring minimal downtime and maintenance.
Unmatched Versatility in Mounting: Can be installed directly onto NAMUR actuators or piped inline, offering exceptional flexibility for machine design and layout.
Built for Demanding Environments: Offers high ingress protection (IP65/IP67) and is available in multiple body materials (Aluminum, Brass, 316L Stainless Steel) to resist corrosion and physical damage.
Global Safety Compliance: Certified for use in hazardous areas (ATEX Zone 1-21) with approvals from major international bodies, ensuring compliance for global projects.
High Functional Safety: Provides TÜV-certified safety data according to IEC 61508, suitable for use in safety instrumented systems up to SIL 4/AK 7.
Low Power Consumption & Flexible Voltage: Consumes very low power (as low as 3.5W), making it ideal for remote locations, and is available in a wide range of AC and DC voltages.
The following table summarizes the core technical attributes of the ASCO 551 Series. Specific values may vary by exact model configuration.
| Attribute Category | Specification Details |
|---|---|
| Product Type | 5/2 (or 3/2) Solenoid Operated, Air Pilot Return Spool Valve |
| Valve Actuation | Solenoid – Pilot Operated |
| Body Material | Aluminum, Brass, or 316L Stainless Steel |
| Media | Compressed Air, Inert Gases |
| Port Type & Size | 1/4″ NPTF or G BSPP |
| Flow Capacity (Cv / Kv) | 0.87 / 0.75 (Example model); Series range: 0.5 to 1.0 Cv |
| Operating Pressure Range (Air) | 2 to 10 bar (Example model); Series range: Vacuum to 10 bar (150 PSIG) |
| Fluid Temperature Range | -25°C to +60°C (Example model); Special models available from -60°C to +80°C |
| Ambient Temperature Range | -40°C to +65°C |
| Coil Power Rating | Low power, e.g., 3.5W @ 115VAC 50Hz |
| Voltage Options | Wide range available: 24VDC, 110VAC, 115VAC, 220VAC, 480VAC, and others |
| Response Time | Fast switching, typically ≤ 15 ms (open) / ≤ 20 ms (close) |
| Standards & Certifications | ATEX (Zone 1-21), IECEx, UL, CSA, SIL (up to SIL 4) |
| Ingress Protection (IP) | IP65 / IP67 |
| Manual Override | Standard on solenoid-operated versions |
The ASCO 551 Solenoid Valve is engineered for precision and reliability across a broad spectrum of industries:
Industrial Automation & Packaging: Controlling actuators on robotic arms, material handling systems, and automated packaging machinery.
Chemical & Process Industries: Reliable operation in refinery, chemical processing, and life science applications where corrosion resistance and hazardous area certifications are critical.
Energy & Environmental Systems: Used in boiler feed systems, gas pipeline safety shut-off, pulse-jet cleaning for dust collectors, and wastewater treatment plants.
Food, Beverage & Pharmaceutical: Suitable for hygienic and cleanroom-sensitive environments, with options for clean air operation and exhaust port piping.
Choosing the ASCO 551 Series means investing in a component backed by over a century of fluid control innovation from Emerson. Its compact size, rugged construction, and global approval pedigree provide a future-proof solution that reduces risk, simplifies system integration, and ensures long-term operational integrity in your most critical applications.
For detailed datasheets, CAD drawings, or to discuss your specific model requirement (such as EFG551, WBLP8551, SCG551), please do not hesitate to contact us.
For more information, technical support, or pricing on the ASCO™ 551 Series, please contact the sales team at Kateteco. We are here to help you select the perfect valve for your application.
Have questions about specifications or suitability for your project? Reach out to the Kateteco sales team today.
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KateTeco (Tianjin) Technology Co., Ltd. serves as an outstanding partner in the field of industrial fluid automation, specializing in the introduction and integration of high-end valves and instruments. We are committed to providing customers with safe, reliable, and intelligent system solutions. By leveraging global leading product resources and supported by systematic professional training and on-site technical assistance from Emerson’s experienced engineers, we ensure that customers can respond promptly and accurately to technical challenges.
With full lifecycle services covering installation, commissioning, operation, maintenance, and replacement, we deliver a true one-stop service system. This allows our customers to enjoy seamless, efficient, and high-quality assurance, supporting enterprises in achieving stable operation and continuous upgrades.
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