ANSI Flange Swing Check Valves

ANSI Flange Swing Check Valves (Brand: Bolaisi, Model Series: H44W/Y-150LB/300LB/600LB/900LB) are fully automatic self-operated one-way valves without external driving devices, designed to deliver reliable anti-backflow protection for industrial fluid pipeline systems.Crafted from high-quality stainless steel, the valve is compatible with water, oil, steam and various industrial media, and can operate stably for a long time under normal pressure conditions. Featuring low flow resistance, high sealing performance and strong compatibility, it serves as an essential basic valve to ensure pipeline safety and stable process operation.

Core Technical Parameters

Structural Design & Core Performance Advantages

The ANSI flange swing check valve adopts a precisely optimized single swing disc structure, consisting of a high-strength valve body, sealed bonnet, inclined valve seat, swing disc, transmission rocker and fully built-in pin shaft. The valve disc rotates smoothly to open and close around the hinge shaft, with the overall design balancing operational efficiency and safety reliability.

Key Performance Advantages

Ultra-low Flow Resistance & High Transmission Efficiency

Adopting a straight-through flow channel and optimized flow field layout with inclined valve seat, it greatly reduces fluid turbulence and local pressure loss. With minimal resistance during forward medium flow, it ensures high pipeline transmission efficiency and lower energy consumption for long-term operation.

Leakage-proof Design & High Safety Factor

Equipped with a fully built-in pin shaft structure, it completely eliminates leakage points caused by extended valve stems compared with traditional externally hinged valves. It is well suited for volatile, flammable and explosive media such as oil and steam, eliminating safety and environmental risks of medium leakage.

Flexible Installation & Strong Compatibility

Supports both horizontal and vertical pipeline installation without customized mounting requirements, adapting to complex industrial pipeline layouts. The full-bore range covers DN15 to DN800, with structurally reinforced design for large-diameter conditions. It ensures smooth opening and closing without jamming, delivering superior compatibility over similar valves.

Stable Sealing & Fast Response

The fully bonded sealing design between disc and valve seat forms dual compression force via medium pressure and disc self-weight for zero-leakage shut-off. The swing structure delivers rapid response, cutting off the pipeline instantly once backflow occurs to completely block reverse fluid.

No External Drive & Low O&M Cost

Fully automatic opening and closing driven by medium pressure difference and disc self-weight. No external power, air supply or control system is required, with zero manual intervention. The streamlined structure ensures low failure rate, greatly reducing costs for on-site installation, commissioning and long-term maintenance.

Working Principle

The opening and closing of ANSI flange swing check valves are fully driven by pipeline medium pressure difference and disc self-weight, requiring no external power or manual operation. The working process is divided into forward opening and reverse shut-off:

Forward Opening & Smooth Conveyance

When medium flows forward from the inlet and inlet pressure exceeds outlet back pressure, the forward fluid thrust lifts the valve disc. The disc rotates around the built-in pin shaft via the rocker, fully separating from the valve seat to open the flow channel. Media passes through unobstructed with minimum pressure loss, without affecting normal pipeline transmission efficiency.

Automatic Shut-off & Anti-backflow Protection

In case of pump shutdown, upstream pressure relief, sudden pipeline pressure changes and other working conditions, outlet back pressure will quickly exceed inlet pressure. The combined force of reverse medium pressure and disc self-weight drives the disc to rotate back and tightly press against the valve seat, instantly cutting off the flow channel and blocking backflow. It fundamentally avoids material cross-contamination, process disorder, medium pollution and pressure imbalance, and protects core upstream equipment such as pumps and compressors from reverse impact damage.

Application Scenarios & Compliance Standards

With excellent anti-backflow performance, wide working condition adaptability and long-term operational reliability, ANSI flange swing check valves are widely used in core industrial fluid systems:

● Petrochemical production units

● Long-distance oil & gas transmission pipelines

● Refining and chemical processing units

● Industrial water treatment and circulating water systems

● Steam heating and heat energy transmission pipe networks

In above working conditions, the valve effectively solves pipeline backflow problems and eliminates production risks including material mixing, process disorder, medium contamination and pressure imbalance, acting as an indispensable safety protection component for industrial pipeline systems.

Compliance & Quality Control Standards

This series is designed and manufactured in strict accordance with ANSI (American National Standards Institute) specifications. Flange dimensions comply with ANSI B16.5, valve design and pressure-temperature ratings conform to ANSI B16.34, and it also meets relevant API industry requirements for oil and gas applications.Every valve undergoes strict hydrostatic strength testing and sealing performance inspection before delivery, fully meeting industrial standards and on-site operation demands for stable long-term service in harsh industrial environments.