Specification

DN15~DN400 PN16~PN25 WCB Cast Steel Manual Bellow Seal Flange Globe Valve

I. Product Overview

TIANYU WCB cast steel manual bellow seal globe valve is a reliable flow control solution engineered for industrial pipelines handling oil, high-temperature steam, and water. Crafted with WCB cast steel (a common high-performance carbon steel) and featuring a bellow seal structure, it achieves precise shutoff and flow regulation through manual operation. Operating at 20℃~200℃ and PN16~PN25 pressure, it uses a metal bellow to replace traditional packing seals, eliminating stem leakage—a critical issue in systems where media loss or safety risks are concerns. Compliant with industry standards, it is ideal for petroleum, power generation, and general industrial systems, balancing durability, sealing reliability, and ease of operation to meet the demands of medium to high-temperature flow control.

II. Key Attribute Parameters

Size Range: DN15~DN400, covering small to large-diameter pipelines for diverse industrial flow control needs, from small oil lines to large steam pipelines.
Pressure Range: PN16~PN25 (1.6MPa~2.5MPa), adapting to medium-pressure systems such as steam auxiliary pipelines and oil transmission lines.
Temperature Range: 20℃~200℃, with WCB cast steel retaining strength and stability in high-temperature steam and hot oil environments.
Material Configuration:
- Body & Bonnet: WCB cast steel, offering excellent mechanical strength and high-temperature resistance, suitable for most industrial media.
- Bellow: Metal bellow (typically stainless steel 304), forming a hermetic barrier between the stem and media to prevent leakage.
- Disc & Seat: Precision-machined metal components with cone-shaped disc design, ensuring tight sealing and wear resistance.
- Stem: Stainless steel, connected to the bellow to avoid direct contact with media, reducing corrosion and ensuring smooth operation.
- Sealing Material: PTFE auxiliary sealing, enhancing tightness and complementing the bellow seal.
- Connection Type: Flanged, enabling secure, leak-tight integration with industrial pipelines.
Actuation: Manual (handwheel), with intuitive operation for precise flow adjustment.
Design Standards: Compliant with industry standards for dimensions, pressure resistance, and sealing performance, ensuring compatibility with common industrial systems.

Product Overview

III. Features Description

Bellow Seal Zero Leakage: The metal bellow is welded to the stem and bonnet, creating a permanent metal barrier that eliminates stem leakage. Unlike traditional packing seals that degrade over time and require frequent maintenance, this design ensures long-term sealing integrity—critical for preventing steam or oil leakage in high-temperature systems.
Dual Sealing Backup: Combines bellow seal (primary) and packing seal (secondary). If the bellow is damaged, the packing immediately acts as a backup to prevent leakage, providing time for scheduled maintenance and avoiding unplanned shutdowns.
Cone-Shaped Disc for Tight Sealing: The disc features a cone structure that fits precisely with the seat, enhancing sealing performance and extending service life. This design ensures reliable shutoff even after frequent operation, reducing the need for replacement.
Integrated Lubrication Design: The bonnet is equipped with a lubrication port, allowing direct lubrication of the stem, nut, and sleeve without disassembling the valve. This simplifies maintenance and ensures smooth operation over time.
WCB Material Durability: WCB cast steel resists high temperatures and pressure, maintaining structural stability in steam and oil environments. It avoids deformation or cracking, ensuring long-term reliability in industrial use.

IV. Manufacturing Processes

Material Preparation: WCB cast steel ingots undergo strict quality inspection, including chemical composition analysis (to ensure carbon content and alloy proportions meet standards) and ultrasonic testing to detect internal defects.
Bellow Forming: Stainless steel sheets are rolled and welded into corrugated bellows, then precision-welded to the stem and bonnet using automatic rolling welding technology. Helium leak testing is performed to confirm hermetic sealing.
Precision Machining: The valve body, disc, and seat are machined using CNC equipment to ensure dimensional accuracy. The disc and seat sealing surfaces are ground to a smooth finish (Ra ≤1.6μm) for tight contact.
Assembly & Testing:
- Components are assembled with precise torque to ensure stability, including the bellow, stem, disc, and handwheel.
- Hydrostatic testing is conducted at 1.5×rated pressure (e.g., 3.75MPa for PN25) to verify the valve body’s pressure resistance; seat sealing is tested at 1.1×rated pressure to ensure no leakage.
- Operational testing involves 100+ open/close cycles to confirm smooth handwheel operation and consistent sealing performance.

Valve Details

V. Product Advantages

Reliable Leakage Prevention: Bellow seal and dual sealing design eliminate stem leakage, reducing media loss by 99% compared to traditional packing valves. This is critical for energy conservation in steam systems and safety in oil pipelines.
Long Service Life: WCB material and wear-resistant disc/seat extend the valve’s service life to 8~10 years, reducing replacement frequency and maintenance costs. The bellow’s fatigue resistance ensures durability under thermal cycling.
Easy Operation & Maintenance: Manual handwheel operation is intuitive, allowing precise flow adjustment. The integrated lubrication port simplifies maintenance, while the flanged connection enables easy installation and disassembly.
Wide Media Compatibility: Suitable for water, steam, and oil, adapting to diverse industrial environments without material incompatibility issues. WCB cast steel resists corrosion from common industrial media.
Cost-Effective Performance: Balances high sealing reliability and durability with competitive pricing, offering excellent value for medium-pressure industrial systems.

Application

VI. Application Fields

Petroleum Industry: Controls oil flow in storage and transmission pipelines, with zero leakage preventing environmental pollution and reducing oil loss. The WCB material resists oil erosion for long-term use.
Power Generation: Regulates high-temperature steam flow in boiler auxiliary systems, ensuring stable steam supply and avoiding energy waste. The dual sealing design enhances safety in high-temperature environments.
Industrial Heating: Manages hot oil flow in heating loops, using precise throttling to maintain stable temperatures. The bellow seal prevents hot oil leakage, ensuring system efficiency.
Water Treatment: Controls clean water and industrial wastewater flow, with WCB material resisting water corrosion and the flanged connection fitting seamlessly into water pipeline systems.

TIANYU DN15~DN400 PN16~PN25 globe valve: WCB cast steel, bellow seal, manual. 20~200℃, flanged. Zero leakage, dual sealing. Ideal for oil, steam, water systems. Customizable: size, seal material (for special media) to fit industrial needs.