Direct Answer

The main difference in a gate valve flange vs threaded connection lies in pressure capacity, pipe size suitability, and maintenance flexibility. Flanged connections are used in large-bore, high-pressure systems, while threaded connections are designed for small-bore, low-pressure utility pipelines. Therefore, engineers must select the connection type based on system stress, maintenance needs, and long-term leakage risk.

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Introduction

Gate valve connection type directly affects pipeline safety and maintenance efficiency. Flanged and threaded designs serve different engineering scenarios. Therefore, selecting the correct connection method ensures stable sealing performance and reduces operational failure risks in industrial systems.

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1. Flanged Connections: High-Strength Industrial Standard

Flanged gate valves use bolted joints with gasket sealing surfaces to connect directly to pipeline flanges.

Key characteristics include:

• High pressure resistance
• Large-bore suitability (typically >2 inches)
• Easy disassembly for maintenance
• Even load distribution across bolt circle

Therefore, flanged connections are the standard choice for refinery, oil, gas, and chemical pipeline systems.

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2. Threaded Connections: Compact and Cost-Efficient Design

Threaded gate valves use internal or external pipe threads to connect directly to piping systems.

Key characteristics include:

• Compact installation size
• Low material cost
• Suitable for small-bore pipelines
• Fast installation in tight spaces

However, threaded connections are more sensitive to vibration, leakage risk, and thread wear. Therefore, they are mainly used in low-pressure utility systems.

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3. Pressure and Mechanical Limitations

Flanged connections distribute mechanical stress across multiple bolts, making them suitable for high-pressure and high-temperature systems.

In contrast, threaded connections concentrate stress at the thread interface. Therefore, they are not recommended for heavy vibration, thermal cycling, or high-pressure applications.

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4. Material Selection for Industrial Service

Severe industrial environments require advanced metallurgy for both connection types.

VALVA manufactures industrial gate valves using:

• 310S stainless steel (high-temperature resistance)
• 321 stainless steel (anti-sensitization welding stability)
• 2205 duplex steel (corrosion resistance)

Therefore, proper material selection improves sealing reliability for both flanged and threaded systems.

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VALVA Structural Integrity Statement

All VALVA gate valves undergo strict hydrostatic pressure testing in accordance with API inspection standards. This ensures zero-leakage performance across both flanged and threaded connection types before shipment.