Check Valves:

Check Valves
Features and Benefits:

• Water, oil and gas compatible, made from durable and corrosion-resistant materials, reduce downtime and the need for frequent replacements.
• Spring-actuated design swiftly and precisely responds to pressure changes and prevents reverse flow and pressure surges – safeguarding your system – and ensures optimal performance and longevity.
• Soft-seated, bubble-tight shut-off meets or exceeds the most stringent industry standards, including ANSI FCI70-2 Class VI, API 598, MSS-SP-61 and ISO5208, ensuring leak-proof performance and protecting your system from contamination.
• Install in any position, including vertical down and diagonal directions, for maximum versatility and configurability to your unique system layout and requirements.

Frequently Asked Questions

Why does CPV use helical springs in their check valves?

CPV uses helical springs for several reasons, including their robust construction that allows check valves to withstand demanding operating conditions.

Here’s why this durability matters.

Helical springs used in CPV check valves are made from high-quality materials capable of enduring high temperatures and corrosive environments. As a result, check valves equipped with these springs enjoy a longer service life, reducing the need for frequent maintenance and replacement.

What are the most common types of check valves and their applications?

Swing Check Valves

• Simple design with a hinged disc that remains open as fluid flows through. It closes when reverse flow occurs.
• Commonly used in firefighting, flood prevention and various fluid systems.

Stop-Check Valves

• Start, stop, and regulate material flow, preventing backflow.
• Automatically close at low system pressure to prevent damage.
• Used in power plants, boiler systems, petroleum production and more.

Ball Check Valves

• Use a spherical ball to control flow direction.
• Ideal for systems with viscous materials.
• Widely used in industrial and household items, liquid dispensers and pumps.

Silent Check Valves

• Control pressure surges, prevent water hammer, and reverse flow in water pipelines.
• Feature a spring-assisted disc for precise operation.
• Essential for water pipeline systems.

What is a check valve and how does it work?

A check valve is a one-way flow control device that automatically allows fluid or gas to flow in one direction while preventing reverse flow, protecting pumps, equipment and system integrity without requiring external power or control signals. The valve operates through differential pressure, opening when forward pressure exceeds the cracking pressure and spring force (if equipped), and closing automatically when flow stops or reverses direction.

This simple yet critical function prevents backflow that could damage pumps, contaminate systems, or create dangerous operating conditions. CPV Manufacturing’s Silent Check Valves, water, oil and gas compatible, were invented in the 1940s and soon were adopted worldwide, preventing water hammer and pressure surge damage.

How do swing check valves differ from lift or ball check valves?

Swing check valves use a hinged disc that pivots on a hinge pin to allow forward flow and close against reverse flow, making them suitable for horizontal installations with lower pressure drop characteristics. Lift check valves employ a guided disc that moves vertically within the valve body, requiring vertical installation but providing tighter shutoff and faster response times. Ball check valves utilize a spherical element that seals against a seat, offering compact design and excellent sealing but may be more prone to wear in dirty service.

Each design offers specific advantages in terms of pressure drop, sealing capability, response time and installation flexibility. CPV Manufacturing’s comprehensive and wide-ranging lift check valve line provides options for many configurations, engineered with stainless steel construction for exceptional durability in demanding applications.

Where are check valves commonly used, and what applications benefit most from them?

Check valves find essential applications in pump discharge lines to prevent reverse flow damage, water supply systems to prevent contamination, heating and cooling systems to maintain proper circulation, and industrial processes to protect equipment and maintain process flow direction. They’re crucial in applications such as boiler feedwater systems, fire protection sprinkler systems, irrigation networks, pharmaceutical manufacturing and chemical processing where backflow could cause safety hazards, equipment damage, or product contamination.

Marine and offshore applications particularly benefit from check valves due to the challenging operating environments and critical safety requirements. The compact, reliable design makes them ideal for space-constrained installations where maintenance access is limited. CPV Manufacturing check valves have a streamlined design to guarantee the integrity of your piping system.

What is cracking pressure and why is it important for check valves?

Cracking pressure represents the minimum upstream pressure required to overcome the valve’s internal resistance (spring force plus disc weight) and initiate flow. Cracking pressure is a critical factor for proper system operation and pump performance. Low cracking pressure reduces system pressure loss and energy consumption but may compromise sealing against reverse flow, while high cracking pressure provides better shutoff but increases system resistance and pump work requirements.

The optimal cracking pressure depends on system characteristics, pump capabilities and sealing requirements. CPV Manufacturing’s engineered check valves feature precisely calibrated springs and optimized geometries to provide the ideal balance between low cracking pressure and reliable reverse flow prevention.

What causes water hammer in systems with check valves, and how can it be prevented?

Water hammer is a general industry concern that occurs when pressure shock waves develop from abrupt flow changes or valve closures, creating pressure surges that can damage piping, equipment and valves throughout a system. While relief valves themselves don’t typically cause water hammer, they can be affected by pressure surges from water hammer events elsewhere in the system, potentially compromising their ability to function properly when needed.

While relief valves address overpressure protection, CPV Manufacturing’s specific expertise in water hammer prevention centers on their renowned Silent Check Valve technology, developed in the 1940s and now installed worldwide. These innovative valves feature spring-assisted disc mechanisms that prevent the reverse flow and pressure surges that cause water hammer, protecting pumps, pipes and surrounding equipment from the devastating effects of hydraulic shock waves that can snap pump shafts or burst piping systems in industrial applications.

How do I select the right check valve for my application?

Selection criteria include fluid compatibility (ensuring valve materials resist corrosion and degradation), pressure and temperature ratings matching system conditions, flow capacity meeting system requirements and installation orientation compatibility with available space. Additional considerations encompass head loss characteristics, sealing requirements, maintenance accessibility, cost constraints and compliance with applicable codes and standards.

The valve type selection (swing, lift, ball, or specialized designs) depends on installation orientation, space constraints, and performance requirements such as tight shutoff or low pressure drop. Environmental factors like vibration, temperature cycling, and potential contamination also influence material and design selection. CPV Manufacturing’s engineering team provides comprehensive application assistance to help customers select optimal lift check valve configurations, drawing on over 100 years of experience in critical applications to ensure reliable, long-lasting performance.