Check valves, also known as one-way valves, are automatic valves that allow fluid flow in one direction but close to prevent reverse flow. They play an important role in protecting pipelines, equipment, and processes across industries. With various design types available, understanding key differences helps select the optimal check valve for each application. We will examine axial flow valves, China lift check valves, and dual disc check valves – three models commonly found in industrial settings.

Axial Flow Check Valves

Axial flow check valves direct fluid along the axis of the valve body to produce straight-through, non-turbulent flow. Benefits include:

• Compact, lightweight, and streamlined design
• Low pressure loss due to smooth, efficient flow path
• Can handle high flow velocities and high pressure
• Straight-through closure minimizes slam and water hammer effect
• Minimal cavitation and turbulence compared to swing checks

Axial checks are ideal for applications requiring minimal flow restriction.

China Lift Check Valves

Originating in China, lift checks contain a ball or disc attached to a hinge. When open, flow lifts the disc to allow passage through the valve. Benefits:

• Can be installed horizontally or vertically-effective for low pressure systems with vertical flow
• Handle water, sewage, oil, and some chemicals
• Simple construction with only one moving part
• Low cost compared to other check types

Lift checks suit low pressure drainage and pumping applications.

Dual Disc Check Valves

Dual disc models have two hinged discs that seal against seats in opposite directions. Key features:

• Tight shutoff with two sealing surfaces
• Low leakage and slam potential
• Handles high pressure, high temperature, and abrasive fluids
• Suitable for large pipe diameters
• Discs can seal even on very low back pressure
• Provides redundancy if one disc fails

Dual disc checks are ideal for severe service conditions.

Evaluating Check Options

Consider fluid properties, pressure, flow, line sizes, installation factors, and operating conditions when selecting the optimal check valve. Consult manufacturers to pick the right model for each application need.