A check valve is a type of valve that allows fluid (liquid or gas) to flow in one direction only. It prevents backflow, ensuring that the fluid moves efficiently and does not return to the source or damage equipment.
A check valve operates automatically, using the pressure of the fluid to open and close:
Forward Flow (Open Position)
When fluid moves in the desired direction, the pressure pushes the valve open, allowing flow.
Backflow Prevention (Closed Position)
If the flow reverses, the valve closes due to gravity, a spring, or reverse pressure, stopping unwanted backflow.
Common Types of Check Valves
Swing Check Valve – A hinged disc swings open with flow and closes when flow stops or reverses.
Ball Check Valve – A ball moves to block or allow flow, common in simple applications.
Diaphragm Check Valve – A flexible diaphragm allows flow in one direction and seals off in reverse.
Lift Check Valve – A piston or disc lifts when flow is forward and drops back to seal when flow stops.
Spring-Loaded Check Valve – Uses a spring to assist in closing quickly, reducing water hammer effects.
SWING CHECK VALVE
A swing check valve is a type of check valve that allows fluid to flow in one direction and prevents backflow, The primary function of a swing check valve is to prevent backflow in a piping system. It allows full, unobstructed flow and automatically closes as pressure decreases, ensuring that the fluid flows in only one direction.
Dimension: 2″ – 24″
Pressure: Class 150 / 300 / 600 / 900 / 1500 / 2500
Standards:
Design Standard: ASME B16.34 / BS 1668
Face to Face: ASME B16.10
End to End: ASME B16.10
Comply with ASME B 16.5
Butt Weld End: ASME B16.25
NACE MR 0175
Key Features
- Design: Consists of a hinged disc that swings open with forward flow and closes against reverse flow.
- Material: Available in various materials, including stainless steel, carbon steel, and cast iron.
- Operation: The disc swings open when the fluid pressure is higher on the inlet side and closes when the pressure drops or reverses.
- Seal: Can have metal-to-metal or soft seat options for sealing.
Applications
- Water and Wastewater Systems: Commonly used in water treatment plants and wastewater systems.
- Oil and Gas: Suitable for pipelines and processing plants to prevent backflow of hydrocarbons.
- Industrial Processes: Used in various industrial applications to protect equipment and maintain process integrity.
- HVAC Systems: Utilized in heating, ventilation, and air conditioning systems to prevent reverse flow.
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DUAL PLATE CHECK VALVE (WAFER – LUG – DOUBLE FLANGED)
Dual Plate Check Valves are designed to prevent backflow in piping systems. They feature two spring-loaded plates hinged on a central pin, which open to allow flow in one direction and close to prevent reverse flow.
Dimension: 2″ – 24″
Pressure: Class 150 / 300 / 600 / 900 / 1500 / 2500
Standards:
Design Standard: API 594
Metal to metal seating for inherent fire safety
Comply with ASME B 16.5
ASME B16.34 Pressure/Temperature ratings
Retainerless design as standard, no leak path to atmosphere
PED 2014/68/EU (Cat III and below)
Resilient seat option
Dual Plate Check Valves offer several benefits, including reduced weight, cost-efficiency, and reliable performance. They are available in various materials, such as carbon steel, stainless steel, and alloy steel, to suit different applications.
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Ductile Iron Swing Check Valve
Dimension: DN 40 – DN 1200
Pressure: PN 10 / PN 16
Body: Ductile Iron / Cast Iron
Disc: STEEL + EPDM / NBR , Ductile Iron , Cast Iron
Standards:
Design: EN 1074-3
Flanges: EN 1092-1
Face to Face: EN 558 Series 48
Hydrotest: EN 12266-1 (ISO 5208)
A Swing Check Valve is a type of check valve designed to allow fluid flow in one direction while preventing backflow in the opposite direction. It is commonly used in piping systems to protect pumps, compressors, and other equipment from damage caused by reverse flow. The valve operates automatically, using a hinged disc (or “swing”) that opens and closes based on the flow of the fluid.
How It Works:
- Flow Direction:
- When fluid flows in the desired direction, the pressure of the flow pushes the disc open, allowing the fluid to pass through.
- When the flow stops or reverses, the disc swings back to its closed position due to gravity or a spring mechanism, preventing backflow.
- Hinged Disc Design:
- The disc is attached to a hinge or pivot point at the top of the valve body, allowing it to swing freely.
- The disc seals against a seat when closed, creating a tight seal to prevent leakage.
- Automatic Operation:
- The valve operates automatically based on the flow direction, requiring no external power or manual intervention.
Key Features:
- Simple Design:
- Consists of a valve body, a hinged disc, and a seat, making it easy to manufacture and maintain.
- Low Pressure Drop:
- When fully open, the disc moves out of the flow path, minimizing resistance and pressure drop.
- Versatility:
- Suitable for a wide range of applications, including water, oil, gas, and steam systems.
- Durable Construction:
- Available in materials like cast iron, stainless steel, brass, and PVC, depending on the application and fluid type.
- Bidirectional Sealing (Optional):
- Some swing check valves are designed to seal in both directions, providing additional protection against backflow.
Applications:
- Water and Wastewater Systems: To prevent backflow in pipelines and protect pumps.
- Oil and Gas Industry: In pipelines to ensure one-directional flow and protect equipment.
- HVAC Systems: To prevent reverse flow in heating and cooling systems.
- Chemical and Process Industries: For handling corrosive or high-temperature fluids.
- Power Plants: In steam and condensate systems to prevent backflow.
Dual Plate Wafer Check Valve
Dimension: DN 40 – DN 300
Pressure: PN 10 / PN 16
Body: Ductile Iron / Cast Iron
Disc: Stainless Steel / Ductile Iron / Bronze Aluminium
Standards:
Design: EN 1074-3
Flanges: EN 1092-1
Face to Face: EN 558 Series 16
Hydrotest: EN 12266-1 (ISO 5208)
Dual Plate Wafer Check Valve designed with a wafer-style body, making it lightweight, compact, and easy to install between flanges in a piping system. It combines the benefits of a dual plate check valve (fast closure, low pressure drop, and compact design) with the simplicity and cost-effectiveness of a wafer-style valve. This type of valve is widely used in industries where space and weight are critical considerations.
How It Works:
- Flow Direction:
- When fluid flows in the desired direction, the pressure of the flow pushes the two spring-loaded plates open, allowing the fluid to pass through.
- When the flow stops or reverses, the plates quickly close due to the spring force, preventing backflow.
- Wafer Design:
- The valve is designed to fit between two pipeline flanges, held in place by bolts. It does not have its own flanges, which reduces weight and cost.
- The wafer design ensures a tight seal between the valve and the pipeline flanges.
- Spring-Loaded Plates:
- The two plates are hinged in the center and held in the closed position by springs, ensuring rapid closure and minimizing water hammer.
Key Features:
- Compact and Lightweight:
- The wafer design eliminates the need for additional flanges, making the valve lighter and more space-efficient.
- Fast Closure:
- The spring-loaded plates close quickly, reducing the risk of water hammer and protecting the system from damage.
- Low Pressure Drop:
- When fully open, the plates create minimal obstruction to flow, resulting in low pressure drop and high flow efficiency.
- Easy Installation:
- The wafer design allows the valve to be installed between flanges, simplifying installation and reducing costs.
- Durable Construction:
- Available in materials like carbon steel, stainless steel, and alloy steels, depending on the application and fluid type.
Applications:
- Water and Wastewater Systems: To prevent backflow in pipelines and protect pumps.
- Oil and Gas Industry: In pipelines to ensure one-directional flow and protect equipment.
- Power Plants: In steam and condensate systems to prevent backflow.
- Chemical and Process Industries: For handling corrosive or high-temperature fluids.
- HVAC Systems: To prevent reverse flow in heating and cooling systems.
Ductile Iron Ball Check Valves
Dimension: DN 50 – DN 600
Pressure: PN 10 / PN 16
Body: Ductile Iron / Cast Iron
Ball: Carbon Steel+ NBR or Ductile Iron + NBR
Standards:
Design: EN 12334
Flanges: EN 1092-2
Hydrotest: EN 12266-1 (ISO 5208)
Ductile Iron Ball Check Valves are a type of check valve designed to prevent backflow in piping systems. They use a free-floating or spring-loaded ball as the closing mechanism, which moves in response to fluid flow. When the flow stops or reverses, the ball seats itself against the valve’s sealing surface, blocking reverse flow. Ductile iron construction makes these valves robust, durable, and suitable for a wide range of applications, particularly in water, wastewater, and industrial systems.
How It Works:
- Flow Direction:
- When fluid flows in the desired direction, the pressure of the flow pushes the ball away from the seat, allowing the fluid to pass through.
- When the flow stops or reverses, the ball returns to its seat, either by gravity or with the help of a spring, preventing backflow.
- Ball Mechanism:
- The ball is typically made of metal, rubber-coated metal, or synthetic materials, depending on the application.
- The sealing surface is designed to provide a tight seal when the ball is in the closed position.
- Ductile Iron Construction:
- Ductile iron, also known as nodular cast iron, provides excellent strength, durability, and corrosion resistance, making it ideal for demanding environments.
Key Features:
- Durable Construction:
- Ductile iron body provides high strength and resistance to impact, making it suitable for high-pressure and heavy-duty applications.
- Tight Sealing:
- The ball and seat design ensures a bubble-tight seal, preventing leakage and backflow.
- Low Maintenance:
- Simple design with few moving parts reduces the need for frequent maintenance.
- Versatility:
- Suitable for a wide range of fluids, including water, wastewater, oil, and gas.
- Compact Design:
- Typically smaller and lighter than other types of check valves, such as swing check valves.
- Optional Spring Assistance:
- Some models include a spring to assist in closing the ball, ensuring faster response and reducing water hammer.
Applications:
- Water and Wastewater Systems: To prevent backflow in pipelines and protect pumps.
- Industrial Processes: In chemical, oil, and gas industries for handling corrosive or high-pressure fluids.
- Irrigation Systems: To maintain efficient water flow and prevent backflow.
- Fire Protection Systems: To ensure one-directional flow in firefighting water systems.
- HVAC Systems: To prevent reverse flow in heating and cooling systems.