The fully welded ball valve is a specialized industrial valve, utilizing a ball as the control element, and is widely used in pipeline systems across industries such as petroleum, chemical, and power generation. Unlike traditional ball valves, the valve body of a fully welded ball valve is connected to the pipeline through welding, completely abandoning the conventional flange connection method. As a result, its structure is more compact and its sealing performance is superior. Fully welded ball valves can not only withstand high pressure and high temperatures but also exhibit excellent corrosion resistance and wear resistance, making them an ideal choice for modern industrial fluid control.
Working principle
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Open position (Fluid flow)
When the valve needs to be opened, the actuator (manual, pneumatic, electric, etc.) rotates the valve stem clockwise by 90 degrees (1/4 turn). The valve stem drives the internal ball to rotate synchronously, aligning the circular passage hole at the center of the ball perfectly with the pipeline axis. At this point, the medium (such as natural gas, petroleum, steam, etc.) flows unimpeded through the ball passage along the pipeline direction, and the valve is fully open.
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Closed position (Fluid shut-off)
When the valve needs to be closed, the actuator rotates the valve stem counterclockwise by 90 degrees. The ball rotates to a position where its passage hole is perpendicular to the pipeline axis. The solid portion of the ball completely blocks the pipeline, while the ball surface is tightly pressed against the seat seal under medium pressure, forming a rigid seal. Medium flow is completely cut off, achieving zero leakage (compliant with ISO 5208 Class A sealing standards).
Types of fully welded ball valves
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In terms of ball support method:
Fixed ball type: The ball is supported by fixed shafts at its top and bottom ends. During valve operation, the ball itself does not displace; instead, the valve seats bear the medium pressure. Advantages: Low operating torque, stable and reliable sealing performance, suitable for large-diameter and high-pressure applications. This is the mainstream choice for long-distance pipelines.
Floating ball type: The ball "floats" within the valve body, relying on medium pressure to push the ball against the outlet seat to achieve sealing. Advantages: Relatively simple structure, commonly used for small-to-medium diameters and medium-to-low pressure applications.
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In terms of drive method:
Manual: Operated via handwheel, lever, or gearbox. Suitable for infrequent operation and where space permits.
Pneumatic: Utilizes compressed air to drive the actuator, enabling quick opening/closing or modulation (requires a positioner). Suitable for frequent operation, remote control, or explosion-proof environments (e.g., chemical plants, oil & gas stations).
Electric: Driven by an electric motor actuator. Suitable for remote control, precise modulation, or integration into control systems (e.g., SCADA systems). This is the core control component for automated long-distance pipelines.
Hydraulic: Driven by hydraulic oil, capable of providing extremely high output torque. Suitable for extra-large, ultra-high-pressure valves or special environments.
Application
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Oil and gas long-distance pipelines: Serve as the final barrier for pipeline safety as shut-off valves on mainlines, branch lines, and station inlets/outlets (e.g., national energy arteries like the West-East Gas Pipeline Project and the China-Russia East-Route Pipeline).
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Urban gas distribution networks: Installed in high/medium-pressure regulating stations, regional shut-off valves, and critical node valves to ensure urban gas supply safety.
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Large-scale petrochemical & refining facilities: Critical isolation valves for pipelines handling high-temperature, high-pressure, flammable, explosive, toxic, or hazardous media.
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LNG receiving terminals & liquefaction plants: Ensure reliable sealing under ultra-low temperature conditions (-196°C).
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Large-scale power generation (Thermal/Nuclear): High-pressure, high-temperature valves for main steam systems and feedwater systems.
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Centralized heating systems: Provide shut-off control for high-temperature hot water/steam trunk networks.
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Subsea pipelines: Withstands extreme external pressure while demanding zero leakage and ultra-long maintenance-free service life.
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Extreme environments: Critical applications requiring exceptional valve strength and reliability, such as permafrost regions, seismic zones, and geologically unstable areas.
Installation
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Professional welding:The valve body-to-pipeline connection employs all-position welding (typically TIG root pass with SMAW fill and cap passes). Welding must be performed by certified welders strictly following qualified Welding Procedure Specifications (WPS). Weld quality directly impacts valve performance and pipeline safety.
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Stress relief: Post-weld heat treatment (PWHT) is typically required for large-diameter or thick-walled valves to eliminate residual welding stresses and prevent stress corrosion cracking.
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Precise positioning & support:
Ensure the valve is fully open before installation. Both the valve and adjacent piping require robust support to avoid additional stress during welding and operation. Large valves necessitate specialized lifting equipment.
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Cleanliness control:
Thoroughly clean pipe bevels and valve ends before welding to remove oil, rust, and contaminants.
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Flow direction indication: Observe the medium flow arrow marked on the valve body to ensure correct installation orientation (critical for uni-directional seal seats).
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Actuator protection: Protect actuators and accessories (e.g., positioners, solenoid valves) from impact during installation. Connect air/power supplies and control signals for pneumatic/electric valves per diagrams.
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Testing & inspection: Upon welding completion, perform 100% non-destructive testing (e.g., RT or UT) on the weld joint. Conduct strength and tightness tests on the entire pipeline system per specifications.
While traditional flanged ball valves may develop micro-leakage under high pressure/temperature due to bolt creep, the fully welded valve body offers:
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Rigid Monolithic Construction: Resists pipeline stress deformation, preserving alignment between the internal ball and seats.
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Zero Dynamic Leak Paths: Static weld seams are over 10 times more reliable than dynamic flange gaskets.
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50+ Year Lifespan: Maintenance-free design suits extreme applications like nuclear plants and subsea pipelines.
Taloar fully welded ball valves
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One-piece fully welded valve body design.
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Offers reduced bore valves or full-bore, low water resistance, and large flow design as options.
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Spring loaded PTFE + C carbon-fiber sealing seat.
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Bi-directional sealing to ensure zero leakage, easy to install.
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High-quality stainless-steel balls.
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Blowout-proof shaft design to ensure safe operation.
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Replace the O-ring on line.
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Double-sealed fireproof design of the valve metal seat to avoids seat damage due to fire.
Taloar WB series are fully welded ball valves, compact, long service life, maintenance is just your original purchase cost! Design and manufacture conform to EN488, EN12266, and GOST.
As a professional valve manufacturer, Taloar is dedicated to offering its customers the highest quality fully welded ball valve products on the market. Should you have any special customized products, please contact us.
If you need to keep up with innovations and technological advancements in fully welded ball valves, Taloar will support you! For more details, please contact sales@taloar.com or WhatsApp 008618112507128.
