The Swedamper S400 is a disc damper designed for industrial flue gas and process systems where complete shut-off and high tightness are critical requirements. The damper features a double-offset construction with a three-point linkage, providing 100% geometric sealing and a compact installation design.
When the damper closes, the process flow pushes the blade against the sealing surface, meaning that pressure and flow assist in maintaining tight shut-off — ideal for applications with high differential pressure.
A flue gas damper is a key component for controlling draft and divert flue gas flow in industrial duct systems.
Certification
ATEX (Ex) Category 3 for Zone 2 Gas and Zone 22 Dust (II 3 GD)
See also our Butterfly Damper S200 for applications requiring high temperature resistance, harsh operating environments, and continuous operation.
The Swedamper Disc Damper S400 is developed for industrial installations where safe shut-off, high tightness, and operational reliability are critical requirements. The damper is designed to fully open or completely close flow in a duct and is particularly suitable for systems requiring a reliable on/off function — for example in bypass lines to chimneys or filters, or at the inlet and outlet of air handling units and process ducts.
The S400 handles both clean gases and gases with moderate particulate content. It is used for shut-off, emission control, and ensuring tight isolation in flue gas and process lines. By optimizing shut-off performance, plants can meet strict environmental and emission standards while maintaining stable and energy-efficient operation.
The Disc Damper S400 features a heavy-duty, compact, and stable design with a double-offset through-shaft where the blade is suspended in a three-point linkage system.
The combination of blade geometry (flat or dished depending on size and application) and linkage system ensures 100% geometric sealing, with uniform surface pressure distributed around the entire circumference — minimizing leakage and wear.
The damper is installed so that process flow pressure pushes the blade against the sealing surface. This means the process pressure itself assists in maintaining tight shut-off. The S400 is therefore particularly well suited for systems with pulsations and high differential pressures where conventional dampers may struggle to maintain tightness over time.
Stuffing boxes on both sides in stainless steel, equipped with double ball bearings
Robust housing and blade designed for continuous operation in demanding industrial environments
Design prepared for pneumatic or electric actuators, or manual operation depending on selected options
To meet different temperature, corrosion, and wear environments, the S400 can be manufactured in a wide range of material combinations. Housing, blade, and flanges can be produced in different alloys and mixed within the same unit — for example, one material in the housing and another in the blade to optimize both service life and cost efficiency.
Available sealing materials include:
PTFE
Fiberglass
Silicone
Additional materials available upon request
Sealing materials can be selected based on chemical environment, temperature, steam exposure, weak acids, alkalis, and abrasive conditions. This enables customized solutions for:
Flue gases from combustion plants
Hot air and process gases
Chemically aggressive atmospheres
Environments with varying temperature and humidity
The Disc Damper S400 covers a wide sizing range and can be adapted to both round and rectangular duct systems:
Maximum temperature: up to approx. 750°C depending on material combination
Size range: DN250–DN2900
Round, square, and rectangular configurations available
Flanges are manufactured according to customer specifications — either Swedamper standards or other recognized international standards.
The S400 can also be equipped with various actuator types, mechanical locking systems, and customized connections depending on process requirements.
The Disc Damper S400 is widely used in energy and process industries where tight shut-off of flue gases or process gases is essential:
Bypass dampers to chimneys or filters in flue gas systems
Isolation at inlets and outlets of air handling units and ventilation ducts
Flue gas shut-off in boiler plants, district heating plants, and CHP facilities
Process lines in steel, chemical, pulp, and paper industries
Emission control and environmental systems requiring high tightness
Installations where reliable on/off functionality is critical for safety, maintenance, and service
In addition to the standard version, the S400 can be supplied with various adaptations, including:
–M (Marine) – configurations for offshore and marine installations
–T (T-duct configuration) – two dampers integrated into a T-duct for switching between duct lines or bypass systems
The construction can also be modified to meet specific requirements such as:
Specific actuator types or position indication systems
Enhanced corrosion protection
Custom flange dimensions and connections
Integration into existing flue gas or process lines
The Swedamper Disc Damper S400 is a high-performance industrial damper for applications where complete shut-off, high tightness, and robust construction are essential.
With its double-offset design, three-point linkage system, customizable materials, and broad application range, the S400 is a natural choice for industrial flue gas and process systems seeking to combine operational reliability, environmental performance, and low life-cycle cost.
| Temperatur | < 750°C |
|---|---|
| Storlek | DN250 – 2000 |
| Anpassningar | -M (Marin), -T (T-rör) |
When selecting a damper for industrial flue gas and process systems, both the Butterfly Damper S200 and the Disc Damper S400 are robust solutions — but they are developed for different functions and operating conditions.
Below are the key differences:
Used for regulating and controlling the volume of flue gases or air.
Ideal for combustion plants, district heating facilities, smelters, and duct systems where flow needs to be throttled, adjusted, and optimized.
Suitable for both low and very high temperatures (up to approx. 1100°C depending on material)
Designed for continuous process operation
Typically operates in partially open positions
In short: Choose S200 when you need precise flow control.
Used to completely open or shut off flow, for example in bypass systems, chimneys, filters, or air handling units.
Delivers 100% geometric tight shut-off thanks to its double-offset shaft and three-point linkage
Process pressure assists in maintaining tight closure
Excellent for applications with strict environmental and emission control requirements
In short: Choose S400 when you need complete isolation and maximum tightness.
Through-shaft design
Blade welded across the entire shaft
Reinforced with blade ribs
No bolted components in the gas flow
Available in numerous alloys for extreme heat and high dust content
→ Designed to withstand wear, vibration, and high temperatures during regulating operation.
S400 – Double-Offset Disc Damper
Double-offset shaft design
Disc suspended in a three-point linkage
Flat or dished blade depending on size
100% uniform surface pressure against the seal
No purge air required
Stuffing boxes on both sides, double ball bearings as standard
→ Designed for tight shut-off in demanding industrial environments.
Up to 1100°C depending on material
Suitable for clean gases and high dust loads
Highly flexible material selection (carbon steel, stainless steel, acid-resistant grades, 253MA, 254SMO, Alloy 800HT, etc.)
→ Ideal for steel plants, smelters, boilers, and extreme high-temperature processes.
Up to 750°C according to datasheet
Suitable for clean gases and moderate dust content
Sealing options include PTFE, fiberglass, silicone for various chemical environments
→ Ideal for duct isolation, gas cleaning systems, filter bypass solutions, and heavy industrial ventilation systems.
Not designed for 100% tight shut-off
Primarily a control component
Handles very high temperatures
100% geometric tightness
Process pressure enhances sealing performance
Can often replace dual-damper + purge air systems
→ Lower investment cost
→ Reduced operating cost
| Requirement | Choose S200 | Choose S400 |
|---|---|---|
| Flow regulation | ✔ | ✘ |
| Full shut-off / On-Off | ✘ | ✔ |
| Very high temperatures | ✔ up to 1100°C | ✘ up to 750°C |
| High tightness | ✘ | ✔ 100% geometric sealing |
| Chimney / filter bypass | ✘ | ✔ |
| Filter isolation / air handling | ✘ | ✔ |
| Smelters, district heating, extreme heat | ✔ | ✘ |
| Replace dual dampers / purge air systems | ✘ | ✔ |
