Stainless steel butterfly valves with pneumatic actuator
SSIS Butterfly Valves – Stainless Steel Butterfly Valves with Pneumatic Actuator
The SSIS butterfly valves from STASTO are double-eccentric stainless steel valves with a pneumatic rotary actuator – designed for reliable shut-off and control in demanding industrial processes. Body and disc are made of stainless steel 1.4408, the shaft of 1.4542, and the seat of Inconel 625. Available in the BUW9-SSIS and BUL-SSIS series, covering nominal sizes DN 50 to DN 500, you will find the right configuration – wafer or lug style, double-acting or single-acting, with or without ATEX.
SSIS – double eccentric in stainless steel 1.4408
Your benefits
Why SSIS butterfly valves from STASTO?
A robust material combination, double-eccentric design and pneumatic rotary actuator – engineered for demanding process applications.
Full stainless steel 1.4408 construction
Body and disc in stainless steel 1.4408, shaft in 1.4542, seat seal in Inconel 625 – a durable material combination for corrosive and thermally stressed media.
Double-eccentric design
The double-eccentric bearing arrangement ensures minimal seat wear and smooth opening and closing behaviour.
Pneumatic rotary actuator
Double-acting or single-acting actuators (e.g. PAD100-H, PAD115-H, PAS1255-H) with a control pressure of 5.5 to 8 bar – depending on series and nominal size.
Standard face-to-face EN 558-1 R20
Standardised face-to-face length and flange pressure rating PN 10/16/25 or ANSI 150 (depending on version) for straightforward integration into existing pipelines.
Series Overview
SSIS butterfly valves by series
From wafer-style to manually operated variants – choose the right SSIS series for your plant.
Series Comparison
SSIS Series at a Glance
Body style, actuator type and ATEX version differentiate the SSIS series. The technical codes assist in direct product selection.
| BUW9-SSIS-D4 | BUW9-SSIS-D4-A | BUL-SSIS-D2-A | BUL-SSIS-S2-A | |
|---|---|---|---|---|
| Body Style | Wafer | Wafer | Lug | Lug |
| Actuation type | Pneum. double-acting | Pneum. double-acting | Pneum. double-acting | Pneum. single-acting (spring return) |
| ATEX version | No | ATEX II 2 G/D | ATEX II 2 G/D | ATEX II 2 G/D |
| Pressure range | 0…25 bar (variant-dependent) | 0…25 bar (variant-dependent) | 0…10 bar (variant-dependent) | 0…10 bar (variant-dependent) |
| Fail-safe position | – | – | – | Defined on air supply failure |
Buyer's Guide
Selecting the right SSIS butterfly valve
Four questions lead you to the right version – from body style to ATEX requirements.
Body style & actuator
- Wafer type (Series BUW9)
- Installed between two pipe flanges – the classic wafer-type mounting situation.
- Lug type (Series BUL/BULV)
- Lug-type body style, suitable for line ends among other applications.
- Double acting
- Actively opens and closes via compressed air in both directions.
- Single acting (spring return)
- Moves to a defined fail-safe position on loss of air supply – relevant for safety concepts.
Certification & design
- ATEX version
- For hazardous areas, SSIS series are available in ATEX versions (ATEX II 2 G/D) – depending on variant.
- Flange pressure rating
- PN 10/16/25 or ANSI 150, depending on series and version.
- Pressure range
- Varies by series – check the specifications of the specific variant.
- Face-to-face length
- Designed to EN 558-1 R20 for predictable installation.
Availability & Configuration
Available depending on series and variant
The SSIS modular system offers a wide range of options. To ensure you receive the right configuration, we will check availability and details together with you.
Wide nominal size range
Depending on the series, the range extends from DN 50 to DN 500 and above. Not every combination of nominal size, actuator and configuration is equally available.
Availability at product level
Stock levels and delivery times are best checked directly on the relevant product/variant page or by contacting our sales team.
Configuration to requirements
We are happy to coordinate actuator type, accessories and certification with you – please get in touch regarding your application.
Applications
Where SSIS Butterfly Valves Are Used
Wherever stainless steel resistance and automated switching are required.
Process & Chemical Engineering
Shut-off and control of liquid and gaseous media in piping systems.
Chemical Plants
The material combination of 1.4408 and Inconel 625 seat is suitable for corrosive media in chemical process control.
Automated Shut-Off Functions
Double-acting actuators for active opening and closing; single-acting actuators for a defined fail-safe position on loss of compressed air.
Pneumatically Actuated Systems
Actuator control pressure in the range of 5.5 to 8 bar – matched to common compressed air supplies.
Plants with Stainless Steel Requirements
Full stainless steel construction for processes with high demands on material resistance.
Processes with Elevated Temperatures
The material combination is designed for a wide temperature range (in many series −10 … +425 °C, depending on variant).
Frequently Asked Questions
FAQ on SSIS butterfly valves
Answers to the most important questions about materials, nominal sizes, ATEX and actuator types.
What materials are SSIS butterfly valves made of?
The body and disc are made of stainless steel 1.4408, the shaft of 1.4542, and the seat of Inconel 625. This combination is designed for corrosive and thermally demanding media.
What nominal sizes are available?
The SSIS range covers a wide span from DN 50 to DN 500 and larger. Which nominal sizes are available in which version can be found on the respective product page.
What does "double eccentric" mean?
In the double-eccentric design, the disc is offset twice relative to the shaft axis. This reduces contact between the disc and seat during opening and extends seal life.
Are SSIS valves available in ATEX versions?
Yes, several series (e.g. BUW9-SSIS-D4-A, BUL-SSIS-D2-A, BUL-SSIS-S2-A) are available in ATEX version (ATEX II 2 G/D) – depending on the selected variant.
What is the difference between double-acting and single-acting actuators?
Double-acting actuators are operated by compressed air in both directions. Single-acting actuators use a spring for return and move to a defined fail-safe position on loss of air supply.
What control pressure is required?
The control pressure of the pneumatic actuators ranges from 5.5 to 8 bar depending on the series.
Which standard defines the face-to-face length?
The face-to-face length of the SSIS butterfly valves complies with EN 558-1 R20. The flange pressure rating is PN 10/16/25 or ANSI 150 depending on the version.
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Configure the right SSIS butterfly valve
Already know your nominal size and actuator type? Go straight to the matching series. Not sure which version suits your application? Our sales team is happy to advise you on body style, actuator, pressure rating and ATEX version.