By Aik Soon Hardware Pte Ltd | Singapore’s Trusted Marine & Industrial Valve Stockist

Check valves are essential components in marine, offshore, and industrial piping systems. These self-acting valves ensure unidirectional flow, preventing reverse flow that could damage equipment, disrupt processes, or pose safety hazards.

At Aik Soon Hardware Pte Ltd, a trusted stockist in Singapore with decades of experience, we understand the critical role check valves play in protecting your systems. In this guide, we break down everything you need to know—from the types of check valves to how to select the right one for your application.

What is a Check Valve?

A check valve, also known as a non-return valve or one-way valve, is designed to allow fluid (liquid or gas) to flow in only one direction. The valve opens automatically when the inlet pressure exceeds a minimum threshold (called cracking pressure), and it closes when the pressure drops or reverses direction, preventing backflow.

Because they operate automatically without any external actuation or manual control, check valves are ideal for protecting pumps, maintaining pressure, and avoiding process contamination. They're widely used across marine, oil and gas, water treatment, HVAC, and chemical processing industries.

Types of Check Valves

Swing Check Valve

This type of valve features a hinged disc that swings open to allow flow and closes by gravity or backpressure to stop reverse flow. It is commonly used in horizontal pipelines and is best suited for applications with consistent flow direction. Swing check valves offer low pressure drop and a straightforward design, making them suitable for water, oil, and non-corrosive gas systems.

Lift Check Valve

Lift check valves use a guided disc or ball that lifts vertically when forward flow occurs. Once the pressure falls or reverses, gravity or backflow pushes the disc back down to its seat. These valves provide a reliable seal and are often used in high-pressure applications, especially where the media is clean and non-viscous. They are suitable for steam, condensate return, and high-pressure water systems.

Wafer (Dual Plate) Check Valve

Wafer check valves are compact valves designed to fit between two flanges. They use a pair of spring-loaded plates that fold inward with flow and close quickly when flow stops or reverses. These valves are lightweight and reduce water hammer due to their fast response time. Their slim profile makes them ideal for installations with limited space, such as marine engine rooms and industrial skids.

Silent (Spring-Loaded) Check Valve

Silent check valves use a spring-assisted disc or piston that opens under forward pressure and closes quietly before flow reversal occurs. These valves are effective in eliminating water hammer and provide quiet operation. They are used in high-rise buildings, vertical piping systems, and process lines where frequent flow changes occur.

Ball Check Valve

Ball check valves operate using a ball that moves away from the seat under forward flow and returns to seal when flow reverses. They are simple in design and suitable for handling fluids with suspended solids or viscous media. These valves are commonly used in wastewater treatment, chemical dosing systems, and slurry pipelines.

Connection Types

Choosing the correct end connection is essential to ensure compatibility and reliability in your system.

Flanged Ends
Flanged check valves are bolted to piping systems using standard flanges, making them easy to install, remove, and maintain. These are commonly used in heavy-duty industrial and marine applications where strength and ease of servicing are priorities.

Threaded Ends (NPT/BSPT)
Threaded valves are typically used for smaller pipeline systems or low-pressure applications. They are quick to install but may require more attention to sealing, especially when dealing with thermal expansion or vibration.

Wafer or Lug Type
These valves are mounted between flanges and are ideal when space is limited. Wafer-type valves are economical and compact, while lug-type valves can be installed in systems that require isolation without disturbing the rest of the pipeline.

Socket Weld / Butt Weld
Welded connections offer strong, permanent joints that are ideal for high-pressure, high-temperature environments. These are commonly found in oil and gas processing, power generation, and chemical plants.

Materials Used in Check Valves

Material selection plays a vital role in determining the valve’s lifespan, resistance to corrosion, and suitability for specific media and operating environments.

Cast Iron
Cast iron is cost-effective and suitable for low-pressure water systems, such as HVAC and general plumbing. It should not be used with corrosive fluids or in marine environments.

Ductile Iron
Ductile iron has higher tensile strength than cast iron and is suitable for potable water systems and industrial pipelines with moderate pressure.

Carbon Steel
Carbon steel is strong, durable, and suitable for high-pressure and high-temperature applications. However, it may require additional protection or coatings for use with corrosive media.

Stainless Steel (304/316)
Stainless steel is highly resistant to corrosion, making it ideal for marine, chemical, and food processing applications. Type 316 stainless steel offers superior resistance to saltwater and acidic environments.

Bronze / Brass
These metals are often used in marine environments due to their corrosion resistance. Bronze is also used in potable water systems and for applications involving seawater or brine.

PVC / uPVC / CPVC
Plastic valves are corrosion-resistant, lightweight, and easy to install. They are best used in low-pressure and non-critical systems handling aggressive chemicals or wastewater.

When Should You Use a Check Valve?

Check valves are essential in systems where reverse flow could cause damage or inefficiency. Common use cases include:

• Pump discharge lines to prevent reverse flow when the pump is off.

• Marine bilge and ballast systems to avoid backflow of seawater into compartments.

• Chemical injection systems to stop backflow from contaminating tanks or metering equipment.

• Fuel transfer systems to maintain unidirectional flow and prevent leakage or backpressure.

• Steam condensate return lines to ensure proper drainage without pressure loss.

Using check valves in the right locations helps reduce downtime, improve system safety, and prevent expensive damage to pumps, compressors, and process equipment.

Factors to Consider When Choosing a Check Valve

Flow Characteristics and Pressure Drop
Some valves (like wafer or swing types) offer minimal resistance to flow, while others (like lift or silent types) may have higher pressure drops. Understanding your flow rate and system pressure is crucial.

Installation Orientation
Not all valves can be installed in both horizontal and vertical positions. Swing check valves are typically suited for horizontal lines, while spring-loaded and lift check valves can often be installed vertically if the flow direction is upward.

Cracking Pressure
This refers to the minimum pressure required to open the valve. In systems with low flow or low pressure, select a valve with a lower cracking pressure to ensure it operates correctly.

Fluid Type
Media characteristics such as temperature, viscosity, and corrosiveness will influence the choice of both valve type and material. For example, slurry requires a ball check valve, while aggressive chemicals call for corrosion-resistant materials like stainless steel or PVC.

System Constraints
If the space available for installation is limited, wafer-style check valves are ideal due to their slim profile. In noisy systems, silent check valves help reduce vibration and prevent water hammer.

Maintenance Access
Consider how easy it is to access and service the valve. Flanged valves are easier to remove for maintenance, whereas welded valves are more permanent and may require cutting to replace.

Why Choose Aik Soon Hardware Pte Ltd?

Aik Soon Hardware Pte Ltd is a leading stockist of industrial and marine valves based in Singapore. Our advantages include:

• A wide range of check valves in stock for immediate delivery

• Compliance with international standards including API, ASME, JIS, and DIN

• Competitive pricing for bulk orders and project requirements

• Expertise in supplying valves for marine, offshore, oil & gas, and building services

• Technical consultation to ensure proper valve selection and system integration

Whether you need a single replacement valve or a full set for a ship refit or industrial plant upgrade, we are here to support your operations with fast and reliable supply.

Conclusion

Check valves may be simple in design, but they play a crucial role in ensuring safe and efficient fluid control across a wide range of industries. By understanding the different types, materials, end connections, and performance factors, you can make a well-informed decision when choosing a check valve for your system.

Aik Soon Hardware Pte Ltd is proud to be a trusted valve supplier in Singapore. Our team is ready to help you source the right check valves for your project—backed by technical knowledge, a wide inventory, and a strong commitment to service.

Contact Us
For product enquiries, technical support, or quotations:

Phone: +65 6292 1155
Email: sales1@aiksoon.com.sg
Website: www.aiksoon.com.sg