GLOBE VALVES
0102030405
DIN BELLOWS SEALED GLOBE VALVE MANUFACTURER
1. Introduction
The DIN Standard EN 12516 GS-C25 Flange Type Bellows Sealed Globe Valve is a high-performance industrial valve designed to ensure leak-free, reliable flow regulation in critical process systems. Built in full compliance with DIN and EN standards, it incorporates a metal bellows sealing system that provides a superior level of tightness, eliminating stem leakage and ensuring extended service life under demanding operating conditions.
The body material GS-C25—a carbon steel grade conforming to DIN 17245—offers excellent mechanical strength, pressure resistance, and thermal stability, making the valve ideal for use in steam, oil, gas, chemical, and power generation applications. Combined with EN 12516 design requirements for pressure-temperature ratings, the valve guarantees high integrity and safety for process control systems across industries.
2. Design Standards and Compliance
The GS-C25 Flange Type Bellows Sealed Globe Valve adheres to several international design and testing standards:
|
Design standard |
DIN 3356 / EN 13709 |
|
Pressure-temperature ratings |
EN 12516-1 |
|
Flange connection standard |
EN 1092-1 (Form B1/B2) |
|
Face-to-face dimensions |
DIN 3202-F1 or EN 558 Series 1 |
|
Testing standard |
EN 12266-1 & 2 (hydraulic and leakage tests) |
|
Marking standard |
EN 19 |
These standards ensure the valve’s mechanical integrity, dimensional accuracy, and pressure containment performance, while maintaining compatibility with other DIN pipeline components and international systems.
3. Material Specifications
The GS-C25 material used for the valve body and bonnet is a cast carbon steel known for its balance of strength, ductility, and weldability. It provides resistance to fatigue and thermal shock, essential for systems handling high-pressure steam or hot water.
Typical Material Composition (GS-C25):
|
Carbon (C) |
0.25% |
|
Manganese (Mn) |
0.6–1.0% |
|
Silicon (Si) |
0.40% |
|
Phosphorus (P) |
≤ 0.035% |
|
Sulfur (S) |
≤ 0.035% |
Standard Material Combination:
|
Component： |
Material |
Specification |
|
Body |
GS-C25 |
DIN 17245 |
|
Bonnet |
GS-C25 |
DIN 17245 |
|
Bellows |
Stainless Steel 1.4541 / 1.4571 |
EN 10088 |
|
Stem |
Stainless Steel 1.4021 / 1.4057 |
EN 10088 |
|
Disc |
Stainless Steel with Hardfacing (Stellite) |
EN 10088 |
|
Seat Ring |
Stainless Steel / Stellite Overlay |
EN 10088 |
|
Gasket |
Graphite / Stainless Steel |
EN 1514-2 |
|
Handwheel |
Cast Iron / Ductile Iron |
EN-GJL-250 |
This material configuration ensures corrosion resistance, wear durability, and long-term stability under cyclic pressure and temperature variations.
4. Bellows Sealing Design
The defining feature of this valve is its bellows-sealed design, which replaces conventional stem packing with a welded multi-layer stainless steel bellows. This design ensures zero leakage through the stem, making it ideal for hazardous, toxic, or high-purity media.
Key Features of the Bellows Assembly:
Multi-ply stainless steel construction for flexibility and fatigue resistance.
Welded to both stem and bonnet, creating a completely sealed chamber.
Secondary packing (graphite) above the bellows provides a backup seal.
Helium leak testing ensures stem tightness.
Design life typically exceeds 10,000 cycles under rated conditions.
Multi-ply stainless steel construction for flexibility and fatigue resistance.
Welded to both stem and bonnet, creating a completely sealed chamber.
Secondary packing (graphite) above the bellows provides a backup seal.
Helium leak testing ensures stem tightness.
Design life typically exceeds 10,000 cycles under rated conditions.
This configuration guarantees emission-free operation, satisfying environmental standards such as TA-Luft (Germany) and ISO 15848-1 for fugitive emissions.
5. Structural Features
a. Body and Bonnet Connection
The body and bonnet are connected by bolted flanges with a precision-machined gasket groove. The use of spiral-wound graphite gaskets ensures reliable sealing even under thermal cycling.
The body and bonnet are connected by bolted flanges with a precision-machined gasket groove. The use of spiral-wound graphite gaskets ensures reliable sealing even under thermal cycling.
b. Flow Control Trim
The valve disc and seat are designed for linear throttling characteristics, providing excellent control accuracy and low pressure loss. The hardfaced trim extends service life under erosive conditions.
The valve disc and seat are designed for linear throttling characteristics, providing excellent control accuracy and low pressure loss. The hardfaced trim extends service life under erosive conditions.
c. Stem and Disc Connection
The stem is threaded and pinned to the disc, ensuring secure engagement while allowing self-alignment on the seat, improving sealing performance.
The stem is threaded and pinned to the disc, ensuring secure engagement while allowing self-alignment on the seat, improving sealing performance.
d. Flange Ends
The ends are flanged according to EN 1092-1, available in pressure classes PN16, PN25, and PN40, ensuring easy installation and maintenance.
The ends are flanged according to EN 1092-1, available in pressure classes PN16, PN25, and PN40, ensuring easy installation and maintenance.
e. Handwheel Operation
A rising stem and non-rotating handwheel design allows precise control of flow. For automated systems, the valve can also be equipped with electric or pneumatic actuators.
A rising stem and non-rotating handwheel design allows precise control of flow. For automated systems, the valve can also be equipped with electric or pneumatic actuators.
6. Applications
The EN 12516 standard defines the allowable pressure-temperature limits for GS-C25 material:
|
Pressure Class |
Max. Pressure (bar) |
Temperature Range (°C) |
|
PN16 |
16 bar |
-10°C to +300°C |
|
PN25 |
25 bar |
-10°C to +350°C |
|
PN40 |
40 bar |
-10°C to +400°C |
These ratings ensure the valve can safely handle high-temperature steam or thermal oil systems without loss of integrity or performance.
7. Working Principle
The bellows sealed globe valve operates on a linear motion principle. When the handwheel is rotated, the threaded stem moves vertically, lifting or lowering the disc to open or close the flow passage.
In the closed position, the disc is pressed firmly onto the seat, ensuring tight shut-off.
In the open position, fluid passes through the flow path with minimal turbulence.
The bellows assembly moves with the stem, isolating the process fluid from the external atmosphere.
This simple yet effective mechanism provides precise throttling and zero stem leakage, making it ideal for continuous operation in critical process lines.
8. Advantages
Zero Leakage Design:
The metal bellows provide a hermetic seal, preventing any emission through the stem—essential for handling toxic, flammable, or corrosive media.
The metal bellows provide a hermetic seal, preventing any emission through the stem—essential for handling toxic, flammable, or corrosive media.
Long Service Life:
The fatigue-resistant bellows can endure thousands of open-close cycles without failure.
The fatigue-resistant bellows can endure thousands of open-close cycles without failure.
Environmental Safety:
Fully compliant with TA-Luft and ISO 15848 fugitive emission standards.
Fully compliant with TA-Luft and ISO 15848 fugitive emission standards.
Maintenance-Free Operation:
No need for frequent packing replacement or adjustment.
No need for frequent packing replacement or adjustment.
Robust Construction:
The GS-C25 body ensures high mechanical strength and temperature tolerance.
The GS-C25 body ensures high mechanical strength and temperature tolerance.
Ease of Installation:
Flanged ends and standardized face-to-face dimensions simplify system integration.
Flanged ends and standardized face-to-face dimensions simplify system integration.
Dual Sealing System:
Backup graphite packing ensures additional protection even if bellows are damaged.
Backup graphite packing ensures additional protection even if bellows are damaged.
Versatile Application:
Suitable for steam, condensate, gas, thermal oil, and aggressive chemical fluids.
Suitable for steam, condensate, gas, thermal oil, and aggressive chemical fluids.
9. Typical Applications
The DIN EN 12516 GS-C25 Bellows Sealed Globe Valve finds wide use in process industries where leakage-free performance is critical:
Power Plants: Steam lines, condensate systems, and feedwater circuits.
Chemical and Petrochemical Industries: Corrosive and toxic fluid control.
Oil & Gas: Refineries, storage, and transfer pipelines.
HVAC and District Heating Systems: Hot water and thermal oil circuits.
Pharmaceutical and Food Industries: Clean and inert gas control.
Paper and Pulp Mills: Steam and process fluid control in digesters and dryers.
Chemical and Petrochemical Industries: Corrosive and toxic fluid control.
Oil & Gas: Refineries, storage, and transfer pipelines.
HVAC and District Heating Systems: Hot water and thermal oil circuits.
Pharmaceutical and Food Industries: Clean and inert gas control.
Paper and Pulp Mills: Steam and process fluid control in digesters and dryers.
Its rugged design and reliable sealing make it suitable for both on-off and throttling services.
10. Inspection and Testing
Each valve is subjected to rigorous quality assurance procedures as per EN 12266 and internal factory standards.
Test Program Includes:
Shell pressure test: 1.5 × nominal pressure.
Seat leakage test: 1.1 × nominal pressure.
Bellows integrity test: Helium leak detection.
Functional test: Stem travel and torque verification.
Visual and dimensional inspection: As per EN 10204 3.1 certification.
All test results are recorded and traceable to the valve’s serial number, ensuring full product accountability.
Shell pressure test: 1.5 × nominal pressure.
Seat leakage test: 1.1 × nominal pressure.
Bellows integrity test: Helium leak detection.
Functional test: Stem travel and torque verification.
Visual and dimensional inspection: As per EN 10204 3.1 certification.
All test results are recorded and traceable to the valve’s serial number, ensuring full product accountability.
11. Optional Features and Variants
Depending on customer requirements, the valve can be customized with several options:
Actuation: Manual, electric, or pneumatic.
Bellows materials: Inconel 625, Hastelloy C, or Monel for corrosive fluids.
Extended bonnet: For cryogenic or high-temperature service.
Drain or vent connections: For system maintenance.
Position indicators or limit switches: For remote monitoring.
Special coatings: Epoxy or zinc-phosphate for outdoor corrosion protection.
Bellows materials: Inconel 625, Hastelloy C, or Monel for corrosive fluids.
Extended bonnet: For cryogenic or high-temperature service.
Drain or vent connections: For system maintenance.
Position indicators or limit switches: For remote monitoring.
Special coatings: Epoxy or zinc-phosphate for outdoor corrosion protection.
These variants allow adaptation to specific industrial needs and operating environments.
12. Maintenance and Service
Thanks to its bellows-sealed design, the valve requires minimal maintenance during its operational life. Regular inspection should focus on:
Verifying smooth operation of the handwheel or actuator.
Checking for external corrosion or gasket leaks.
Ensuring the bellows integrity through operational leak testing.
Checking for external corrosion or gasket leaks.
Ensuring the bellows integrity through operational leak testing.
With proper installation and adherence to pressure-temperature limits, the valve can offer decades of reliable service without requiring major overhaul.