Connection Methods and Installation Characteristics
1. Threaded Ball Valve: Compact and Lightweight, Flexible Installation
Threaded ball valves connect directly to the pipe threads via threads on the valve body end. They come in two types: internal and external threads. This connection method determines the following characteristics:
Limited Applicable Pipe Diameter: Nominal sizes are typically limited to DN50 and below. If the pipe diameter is too large, the installation and sealing difficulty of the connection increases significantly.
Ease of Installation: Small size and light weight allow for single-person operation, making it particularly suitable for scenarios with limited space or requiring rapid installation.
Sealing Requirements: Threaded connections may have leakage channels, requiring the use of sealants, sealing tape, or packing for remediation.
2. Flanged Ball Valve: Robust and Reliable, Suitable for Large Diameters
Flanged ball valves connect to the pipe via flanges. A gasket is installed between the flanges at both ends, and the valves are secured with bolts. Its core advantages include:
Wide Pipe Diameter Coverage: Diameters range from DN15 to DN700, meeting the needs of large-diameter pipelines.
Ease of Installation and Disassembly: Simple and efficient installation and disassembly, suitable for industrial scenarios requiring frequent maintenance or repair.
Pressure Resistance: High structural strength, capable of withstanding higher pressures, but limited temperature resistance; exceeding 350℃ may lead to seal failure.
Structural Design and Performance Comparison
1. Threaded Ball Valve: Lightweight design, quick opening and closing.
Materials and Sealing: Main body materials include stainless steel, carbon steel, and CF8 alloy; valve seat uses PTFE or PEEK engineering plastic seals to ensure bidirectional sealing performance.
Opening and Closing Characteristics: Full opening/closing is achieved through 90° rotation; low flow resistance; compact structure; suitable for applications requiring rapid opening and closing.
Temperature and Pressure Range: Applicable temperature -20℃~200℃, nominal pressure PN16~140, maximum working pressure 500Bar.
2. Flanged Ball Valve: High-strength structure, stable sealing.
Material Variety: Valve body materials include carbon steel, stainless steel, titanium alloy, etc.; nominal pressure range 1.6-10.0MPa, suitable for high-pressure conditions.
Sealing Technology: Employs a PTFE/Ni55/STL embedded seat structure and flexible graphite packing, with spring preloading technology ensuring reliable sealing.
Temperature Resistance: The sealing system can withstand -29℃ to 300℃ (reinforced PTFE seals) or -29℃ to 180℃ (para-position polystyrene seals).
Application Scenarios and Selection Recommendations
1. Threaded Ball Valve: Small pipelines and specific media control
Typical Applications:
Selection Points:
2. Flanged Ball Valve: Core equipment for medium to large-scale industrial projects
Typical Applications:
Selection Points:
Cost and Maintenance Considerations
1. Threaded Ball Valve: Low cost, high maintenance frequency
Economy: Lower material and manufacturing costs, suitable for projects with limited budgets.
Maintenance Challenges: Difficult disassembly and reassembly after damage, especially high maintenance costs in fixed pipelines.
2. Flanged Ball Valve: High cost, low maintenance requirements
Investment Cost: Higher material and processing costs, requires matching flanges and bolts.
Maintenance Advantages: The sealing ring is removable and replaceable, supporting online maintenance and resulting in lower long-term operating costs.
Industry Practices and Standards
Threaded Ball Valves: Comply with standards such as GB/T 12237 and GB/T 12221; threaded connection dimensions conform to GB/T7306 specifications.
Flanged Ball Valves: Follow international standards such as API6D, BS5351, and ISO17292 to ensure interchangeability and safety.
Conclusion: The core differences between threaded ball valves and flanged ball valves lie in their connection method, applicable scenarios, and cost-effectiveness. The former is characterized by its lightweight and low cost, suitable for small pipelines and low-pressure conditions; the latter, with its high strength and ease of maintenance, dominates medium to large-scale industrial projects.
