Check Valves

Check valves, essential components in pipeline systems, are engineered to prevent the reverse flow of fluids and gases. These valves are designed to allow fluid to flow in only one direction, ensuring system integrity. Due to their simple design, check valves generally operate autonomously, relying on the fluid's flow velocity to facilitate opening and closing. This eliminates the need for manual intervention or complex automation.

What Is a Check Valve?

A check valve, also referred to as a one-way valve, is a device that permits fluid flow in a single direction, effectively preventing backflow. This function is crucial for safeguarding against contamination, as reverse flow can introduce impurities into upstream media.

Available in various configurations, including high-pressure check valve and inline check valve designs, these valves are specified by maximum working pressure, thread standard, and body material to suit diverse application requirements.

Check Valve Types

There are several types of check valves for just about any application. Some of the more popular types include:

• Ball check valve: These valves utilise a spherical ball to block reverse flow, ideal for applications with viscous fluids or slurries, ensuring reliable sealing.
• Dual plate check valve: Featuring two spring-loaded plates, these valves offer rapid closure, minimising water hammer and providing efficient flow control in compact spaces.
• Double door check valve: Similar to dual plate valves, these use two hinged doors for quick closure, reducing shock and offering robust performance in demanding systems.
• Spring-assisted inline check valve: These inline check valves use a spring to assist closure, ensuring positive shut-off in low-pressure systems and preventing backflow with enhanced reliability.
• Swing check valve: Swing check valves, including those for larger diameter pipes, employ a hinged disc that swings open with forward flow and closes against reverse flow, suitable for high-flow applications.
• Air check valve: Specifically designed for pneumatic systems, air check valves ensure unidirectional airflow, maintaining system pressure and preventing backflow in compressed air lines.

As with other valves, speciality check valves can be found for special applications.

One-Way Check Valve

One-way check valves, a type of inline check valve, utilise a spring-loaded mechanism. When inlet pressure exceeds the spring's force, it lifts the check ball or disc, allowing fluid or air to flow to the outlet. However, if outlet pressure surpasses inlet pressure, the valve closes, preventing reverse flow.

This control mechanism maintains pipeline pressure, ensuring unidirectional flow. Effectively, the design permits fluid entry but blocks any backflow from the outlet.

Double Check Valve

Double check valves, designed for enhanced reliability, feature two standard check valves arranged in series. This configuration provides dual protection, ensuring that if one valve becomes jammed open, the other maintains the system's integrity.

Furthermore, the closing mechanism of the double check valve minimises pressure differentials across other valves, resulting in a tighter seal and preventing minor leakages.

Double-check valve backflow preventers are particularly effective in preventing back pressure and siphoning in applications like fire sprinklers and lawn irrigation.

Hydraulic Check Valve

Hydraulic check valves are a straightforward yet critical hydraulic component that facilitates unrestricted oil flow in only one direction while blocking it in the reverse. These valves are versatile, serving as both pressure and directional controls within hydraulic systems.

To enhance sealing performance, hydraulic check valves employ a tapered valve core. When circuit closure is necessary, they provide reliable one-way locking, maintaining consistent pressure within the oil circuit.

In addition to hydraulic applications, similar one-way flow control is achieved in systems with pneumatic fittings through the use of pneumatic non-return valves, catering to diverse fluid and air handling requirements.

Factors to Consider When Buying Check Valves

When selecting check valves, several crucial factors should guide your decision to ensure optimal performance and longevity:

• Material compatibility: Verify that the valve material is compatible with the fluid or gas being handled, so as to prevent corrosion, degradation, and potential system failures.
• Flow characteristics: Match the check valve type to your system's flow rate and pressure requirements to avoid issues like water hammer.
• Installation orientation: Confirm the valve's designed installation orientation, as some valves are specifically designed for horizontal or vertical placement, impacting functionality.

Common Mistakes to Avoid When Purchasing Check Valves

When purchasing check valves, it's essential to avoid these common mistakes to ensure optimal system performance and longevity:

• Incorrect sizing: Selecting a check valve without accurately assessing flow conditions can result in performance issues, such as inadequate flow or increased pressure drop within the system.
• Ignoring maintenance requirements: Overlooking the maintenance needs of certain check valves can lead to increased long-term costs. As such, opt for low-maintenance designs where possible to reduce these expenses.
• Overlooking system compatibility: Failing to ensure the check valve's pressure rating and material compatibility with the application can result in premature failures and system damage.

Industry Applications of Check Valves

Water and Wastewater Treatment

In water and wastewater treatment plants, check valves prevent backflow, safeguarding clean water supplies and preventing contamination. Swing check valves are commonly used for their ability to handle large volumes and minimise pressure loss.

Oil and Gas Industry

Within the oil and gas sector, high-pressure check valves are crucial for preventing backflow in pipelines, ensuring safe and efficient transportation of fluids and gases under extreme conditions.

Chemical Processing

Chemical processing plants rely on check valves for controlling the flow of corrosive and hazardous chemicals. Material compatibility is paramount, so stainless steel check valves are often used to ensure durability and prevent leaks.

HVAC Systems

HVAC systems utilise air check valves to maintain proper airflow and prevent backdrafts in ventilation systems, ensuring efficient operation and indoor air quality.

Medical Applications

Medical applications, such as dialysis machines and respiratory equipment, depend on check valves for precise fluid control, ensuring patient safety and treatment efficacy.

Agriculture and Irrigation

In agriculture and irrigation systems, inline check valves prevent backflow in pipelines, maintaining consistent water pressure and preventing damage to pumping equipment.

Your Trusted Check Valves Supplier and Manufacturer in Australia

For a reliable source of quality check valves, including stainless steel check valve and air check valve options, look no further than RS Australia. We source our products from leading brands like SMC, Parker, Legris, and Georg Fischer, ensuring you receive products of good quality.

Beyond check valves, our extensive inventory encompasses a broad range of mechanical tools, from compression springs to pipe clips, streamlining your procurement process.

Order online today and enjoy swift and flexible deliveries. For more information on our delivery options, check out our delivery information page.