Swing check valves are a type of flow control device that only allows fluid flow in one direction while preventing backflow. They feature a hinged disc or clapper that moves to an open or closed position depending on the pressure and flow direction within the valve.
When the fluid is flowing in the permitted direction, the disc swings fully open to allow full flow. But when the flow reverses direction, the increased back pressure causes the disc to pivot and seal tightly against its seat, stopping backflow. This simple yet effective operation makes swing check valves ideal for a variety of applications where backflow prevention is crucial.
Construction And Operation
A typical swing check valve consists of a valve body with an inlet and outlet, a pivoting disc that acts as a check element, and a hinge that allows the disc to rotate freely. Most discs are exposed to the flow media and are made from metals like cast iron, steel, and stainless steel. Some high-end valves feature encapsulated elastomer discs for improved sealing and longevity.
When fluid is flowing in the forward direction, the pressure causes the disc to rotate and seats against the hinge, allowing unrestricted flow through the valve body. As the flow reverses, the backward pressure closes the disc against its seat, creating a tight seal to prevent backflow. The hinge allows the disc to move freely from fully open to fully closed as needed.
Applications Of Swing Check Valves
Swing check valves are widely used in applications where backflow prevention is necessary to ensure system control and safety. Common uses of swing check valves include:
• Preventing back siphonage in water distribution systems. By stopping backflows, these valves help prevent contamination of potable water supplies.
• Draining tanks and equipment. Swing checks provide one-way drainage to remove fluids and condensate from vessels.
• Separating gas from liquid in oil and gas pipelines. The valves from China swing check valve factory allow liquids to drain while preventing gas backflow into low-lying areas.
• Controlling flow in industrial processes. The ability to stop reverse flow while allowing gases and liquids to discharge freely makes swing checks valuable for many process applications.
• Isolating sections of pipe networks. By preventing backflow, swing check valves effectively isolate upstream pipe sections from downstream flow variations.
China As Major Manufacturer
China has emerged as a major global producer and exporter of swing check valves. Chinese factories manufacture valves in compliance with international standards like ANSI, ISO, DIN, and JIS and offer:
• Standard China swing check valve with bronzed, cast iron, or stainless steel bodies.
• High-performance valves with encapsulated flexible disc seats for chemical and pharmaceutical applications.
• Triple-offset and bellows seals for zero-leakage performance.
• Valves rated for high-temperature and high-pressure service.
• Wafer, lug, and flange styles of end connections for simple installation.
When selecting a manufacturer, look for a Chinese factory with a long operating history, certifications like ISO 9001, and experience producing valves for some of the world’s largest industrial end users. The best Chinese valve suppliers also offer customized designs and rapid prototyping and testing services for unique applications.