Description

Technical Data Sheet (English Version)

Product: Bellows Seal Globe Valve
Size / Rating: DN25 – PN25 – SW (Socket Weld)

1. General Description

This bellows seal globe valve features an advanced double sealing system consisting of a metal bellows and a back‑up packing. It completely eliminates stem leakage, making it the ideal choice for critical applications such as high‑temperature steam, thermal oil, toxic or hazardous fluids, and valuable media. It is a direct upgrade from conventional packed globe valves and is widely used in chemical, power, and pharmaceutical industries where environmental compliance and operational safety are paramount.

2. Basic Specifications

Parameter	Specification
Size	DN25 (1”)
Pressure Rating	PN25 (Class 150)
Design Type	Bellows Seal Globe Valve
End Connections	Socket Weld (SW)
Temperature Range	-29°C up to +425°C (depending on bellows & packing material)
Media	Steam, hot water, thermal oil, toxic gases, corrosive fluids

3. Material Specification

No.	Part Name	Standard Material	Upgrade Option
1	Body	A105 (CS) / F304 (SS304)	F316L / F11 (Alloy Steel)
2	Disc	2Cr13 / 304 SS	316L SS / Stellite hardfaced
3	Stem	2Cr13 / 304 SS	17-4PH / Inconel
4	Bellows Assembly	304 / 316L SS (multi‑ply)	Inconel 625 / Hastelloy
5	Packing	Flexible Graphite	High‑temperature graphite + anti‑extrusion rings
6	Bonnet	Same as body	Same as body
7	Handwheel	Cast iron / Carbon steel	Stainless steel / Locking device

4. Key Features

4.1 Zero Leakage Bellows Seal

Double sealing safety – The bellows + packing configuration provides a primary seal (bellows) that eliminates stem leakage, plus a secondary packing seal for added protection.
Long fatigue life – Bellows are tested for over 10,000 cycles to ensure reliable performance under frequent operation.
Environmental compliance – Achieves zero stem leakage, meeting ISO 15848 fugitive emission standards and reducing media loss for safer, more environmentally friendly operation.

4.2 Globe Valve Design Advantages

Flow direction “low in, high out” – Media enters below the disc, ensuring tight shut‑off as system pressure assists sealing.
Throttling capability – Suitable for both isolation and flow regulation.
Easy maintenance – Top‑entry design allows internal components to be serviced without removing the valve from the pipeline.

4.3 Socket Weld Connection

Provides a permanent, leak‑free joint ideal for high‑pressure, high‑temperature, and hazardous media.
Socket weld design offers high mechanical strength and long service life when properly installed.

5. Testing & Standards

Test / Standard	Reference
Design & Manufacture	BS 1873 / ASME B16.34
Pressure Testing	API 598 / ISO 5208
Shell Test	1.5 × PN25 (3.75 MPa)
Seat Leakage Test	1.1 × PN25 (2.75 MPa)
Bellows Endurance Test	10,000 cycles with zero leakage
Fugitive Emission (optional)	ISO 15848‑1 / TA‑Luft

6. Installation & Maintenance Notes

Flow direction – Globe valves are directional. Install according to the flow arrow on the body (flow under the disc).
Welding precautions – For socket weld connections, fully open the valve before welding to prevent heat damage to the bellows and sealing components. Allow slow cooling after welding.
Operating torque – Do not use extensions or excessive force on the handwheel. When closing, turn the handwheel until resistance is felt; for high‑temperature service, re‑tighten slightly after the system reaches operating temperature.
Periodic inspection – Although the bellows is designed for long life, regularly inspect the packing area for any signs of leakage as an added safety measure.

7. Approximate Dimensions (for reference)

Dimension	Value (mm)
Face‑to‑Face Length (L)	~160 (Socket Weld)
Socket Weld End (per ASME B16.11)	Standard socket dimensions
Overall Height (H)	~230
Handwheel Diameter	~100

Note: Final dimensions are subject to the specific design; certified GA drawings should be referenced for engineering purposes.

Remarks:

This valve is recommended for steam, thermal oil, toxic, and valuable media. Material selection should be verified based on actual service conditions.
For actuated versions (electric or pneumatic), an ISO 5211 top mounting flange is available upon request.

DN25-PN25-SW Bellows Seal Globe Valve