Structural Features

• Buried valve body: The valve body adopts an all-welded or flange-connected structure, which can be entirely buried underground to reduce the occupation of above-ground space. The valve body is mostly made of high-strength carbon steel (such as L360, X65) or stainless steel, and the exterior is subjected to anti-corrosion treatment (such as 3PE coating) to resist soil corrosion and underground environmental erosion.
• Ball and sealing: The ball is made of forged steel with a precision-machined surface. It is matched with metal hard sealing or elastic sealing (such as PTFE) to ensure bidirectional sealing under high pressure (up to more than 10MPa) with a low leakage rate. Some models are designed with sewage outlets for regular cleaning of impurities.
• Gas-hydraulic linkage drive: Compressed air (or nitrogen) is used as the power source, and torque is transmitted through hydraulic oil to drive the ball to rotate for opening and closing. The drive device is usually installed in the ground control box for easy operation and maintenance. It has a large output torque and is suitable for large-diameter valves (DN100~DN1000).
• Safety control components: It integrates manual operation mechanisms (for emergency use), limit switches (to feedback valve status), pressure sensors (to monitor pipeline pressure), etc. Some models can be connected to the SCADA system to realize remote monitoring and automatic emergency shutdown.

Working Principle

• Normal operation: By inputting instructions through the ground control box, compressed air pushes the hydraulic pump to work, and hydraulic oil enters the actuator cylinder to drive the valve stem and drive the ball to rotate 90°, completing the opening or closing of the valve.
• Emergency shutdown: When abnormal conditions such as overpressure, pressure loss, or leakage occur in the pipeline, the control system triggers the gas-hydraulic linkage device to quickly cut off the oil circuit or gas circuit, so that the valve closes in a short time (usually ≤15 seconds) to prevent the accident from expanding.

Application Scenarios

• Long-distance oil and gas pipelines: Widely used for segment control of long-distance transmission pipelines for natural gas, crude oil, refined oil, etc., such as nodes like city gate stations, distribution stations, and valve chambers, to realize regional isolation and emergency shutdown of pipelines.
• Underground pipeline network system: Suitable for chemical raw material transmission pipelines that need to be buried underground, reducing the impact of above-ground equipment on the surrounding environment, especially suitable for densely populated areas or landscape-sensitive areas.

Performance Advantages

• Strong weather resistance: The buried part is resistant to soil corrosion and settlement, adapts to complex underground environments such as humidity and temperature changes, and has a service life of more than 20 years.
• Reliable operation: The gas-hydraulic linkage drive combined with the hydraulic amplification principle ensures stable output torque, and can work normally under extreme conditions such as low temperature (-40℃) and high temperature (60℃).
• High safety: It supports remote control and automatic emergency shutdown, and forms a safety closed loop with the pipeline monitoring system to reduce the risk of manual operation.