Difference Between Dual Disc Check Valve and Ducting Non Return Valve

1. Basic Functionality and Purpose

Both the Dual Disc Check Valve and the Ducting Non Return Valve are designed to allow fluid (liquid or gas) to flow in one direction and prevent reverse flow. However, the way they achieve this goal differs.

Dual Disc Check Valve: Also known as a double door check valve or split disc valve, this valve features two spring-loaded semicircular discs hinged on a central pin. These discs swing open with forward flow and close when the flow stops or reverses. The design enables rapid closure, which helps reduce water hammer effects.

Ducting Non Return Valve: Typically used in HVAC (Heating, Ventilation, and Air Conditioning) and ducted systems, this valve controls air or gas flow in ducts and ensures that it only flows in the intended direction. It usually employs a flap, damper, or simple plate that opens under forward airflow and closes under reverse pressure or gravity.

2. Design and Construction

The structural design of each valve reflects its intended use and the medium it controls.

Dual Disc Check Valve:

Constructed primarily from metals like stainless steel, carbon steel, or alloys.

Features two pivoted discs mounted on a central shaft.

Often includes torsion springs to ensure immediate closure upon flow reversal.

Compact wafer-type body that fits between standard flanges.

Designed for high-pressure fluid applications such as in oil and gas, petrochemicals, and water treatment plants.

Ducting Non Return Valve:

Commonly made from lightweight materials such as galvanized steel, aluminum, or even high-grade plastic.

Typically consists of a single flap or damper, sometimes assisted by springs.

Designed for easy installation in round or rectangular ducts.

Used in systems handling low-pressure air or gas, mainly in ventilation systems or air handling units.

3. Applications and Media Compatibility

Each valve type is optimized for specific working conditions and media.

Dual Disc Check Valve:

Suitable for water, steam, oil, and other process fluids.

Operates effectively under high pressure and temperature.

Common in pipeline networks, power plants, chemical refineries, and marine applications.

Can be installed in horizontal or vertical pipe runs depending on design.

Ducting Non Return Valve:

Primarily used in air handling systems to control airflow.

Not intended for liquid applications or high-pressure systems.

Found in HVAC systems, ducted exhausts, and ventilation networks in commercial and residential buildings.

Typically installed in horizontal duct runs or inline with airflow direction.

4. Performance Characteristics

When comparing performance, the dual disc check valve and the ducting non return valve cater to distinct system demands.

Dual Disc Check Valve:

Offers fast closing action to minimize water hammer.

Low-pressure drop due to streamlined flow path.

Requires a small cracking pressure to open the discs.

Engineered to withstand cyclic operations and continuous service.

Ducting Non Return Valve:

Designed for low resistance in airflow.

Closure may rely on gravity or minimal spring force, making it suitable for low-pressure systems.

Not recommended for applications requiring a precise seal or handling aggressive media.

5. Installation and Maintenance

Maintenance practices vary depending on usage intensity and environmental conditions.

Dual Disc Check Valve:

Requires precise alignment during installation.

Regular inspection of springs and hinge pins is necessary in high-cycle operations.

Often installed with upstream and downstream isolating valves for serviceability.

Ducting Non Return Valve:

Easier and quicker to install due to lighter materials.

Maintenance is generally limited to occasional cleaning or flap replacement.

Access panels or removable duct sections are commonly provided for inspection.

6. Cost and Lifecycle Considerations

Cost-efficiency depends largely on the application and material demands.

Dual Disc Check Valve:

Higher upfront cost due to complex construction and durable materials.

Long service life in appropriately matched systems, justifying the initial investment.

Better suited for critical service conditions where failure is costly.

Ducting Non Return Valve:

Lower cost due to simpler design and materials.

Sufficient for low-demand systems where fluid dynamics are less critical.

Lifespan may be shorter, but replacement is simple and inexpensive.