CK check valves (Non-Return Valves) are designed for a max. allowable
working pressure of 6.000 psi. The check valve allows flow in one direction
only, closing the position when the flow reverses. in case you do not find
your product solution please do not hesitate to contact us. CK check
valves are available with a lot of options. We are showing on this page just
the standard types.
VR1 check valves (Non-Return Valves) are designed for a max. allowable
working pressure of 10.000 psi. The check valve allows flow in one
direction only, closing the position when the flow reverses. in case you do
not find your product solution please do not hesitate to contact us. VR1
check valves are available with a lot of options. We are showing on this
page just the standard types.
A check valve (also called a non-return valve or NRV) allows flow in one direction and helps prevent backflow. That sounds simple, but real systems aren’t always gentle. Flow can be low, pulsing, dirty, or fast-changing—especially around pumps. The best check valve is the one that stays stable in your actual operating conditions.
If you’re selecting for a project: don’t start with “which brand.” Start with media, pressure/temperature, normal flow (not only max flow), and installation orientation. Those four inputs narrow the field quickly.
Before you compare designs, it helps to pin down what “one-way” means in practice. A check valve opens when upstream pressure exceeds downstream pressure by enough to move the closure element (disc, ball, piston, or diaphragm). It closes when that differential disappears or reverses.
In forward flow, the valve’s internal element lifts or swings away from the seat so fluid can pass. If flow slows rapidly or reverses, the element returns to the seat and blocks reverse movement. That closure protects equipment, prevents contamination, and can reduce unwanted draining of lines.
Many check valves need a minimum differential pressure to start opening. That threshold is called cracking pressure. In a high-flow water main, cracking pressure may be a footnote. In a low-flow process line or a long pipe with small pressure margins, it can decide whether your system behaves—or quietly struggles all day.
“Check valve,” “non-return valve,” and “one-way valve” are often used interchangeably. In a hydraulic circuit you may see “one-way valve” more often, but the job is the same: stop reverse flow.
Once the basics are clear, the next question is where check valves earn their keep. The application shapes everything: the type, materials, sealing, and how sensitive the valve is to low flow or contamination.
Check valves are common in water distribution, booster systems, irrigation, and treatment-related piping. In water, the usual headaches are corrosion, debris, and pressure surges (water hammer) from quick changes in velocity.
On pump discharge, a check valve helps prevent reverse rotation and keeps the line from draining back. This is also where closing dynamics matter most: a valve that “slams” can trigger noise, vibration, and repeated seat wear.
Steam and condensate services often involve high temperatures, flashing, and erosion risks. The valve type and seat materials need to match the actual phase and the temperature—not just the word “steam” on a drawing.
Gas is less forgiving because it has less damping than liquid. That can make chatter more likely in marginal conditions. Leakage tolerance can also be tighter, depending on the process.
In vacuum or very low differential pressure, many standard check valves won’t behave the way you expect. If the system can pull negative pressure, confirm the valve is rated and tested for that scenario. Small details like seat geometry become big.
Now we can get practical. Check valves share a purpose, but they don’t share the same failure modes. If you know the design’s personality—how it closes, how it handles debris, and how it behaves at low flow—you can avoid most surprises.
Swing checks use a hinged disc that swings open with forward flow and swings shut when flow reverses. They’re common in water and general infrastructure because the design is familiar and often cost-effective.
If you have steady flow and enough space, swing checks can be a solid choice—especially in larger diameters where compact designs become harder to source.
Rapid flow reversals can cause slam. If your system sees pump trips, quick valve closures downstream, or frequent starts/stops, you’ll want to think carefully about closing speed and placement.
Lift (or piston) check valves use a guided element that lifts off the seat under forward differential pressure. The guided motion can improve alignment, but it also means more surfaces can collect deposits.
If you need a more controlled closing element and your media is clean, lift/piston designs can work well in higher-pressure service.
They’re often less tolerant of solids. If you have scale, particles, or sticky fluids, plan for filtration or choose a more forgiving design.
Ball check valves seal using a ball that moves with flow direction. Many are compact and simple, which can be a benefit when you need straightforward maintenance.
They’re often used where compactness matters and where a simple closure element is preferred. Depending on the seat design, they can also handle some contamination better than guided designs.
Wear or debris on the seat can cause leakage. If the valve is buried in hard-to-reach piping, the real failure is often “nobody checks it until it’s too late.”
Diaphragm check valves rely on a flexible diaphragm to open and close. That flexibility can make sealing gentle and can help in certain chemical or dirty services.
If your application values sealing feel and you’re operating inside the diaphragm material’s limits, these valves can be a strong option.
Confirm temperature and media compatibility for the diaphragm material. When a diaphragm fails, it usually fails decisively.
Spring check valves use a spring to bias the element toward the seat. They are often compact and available as in-line designs that fit tight layouts.
Spring force can help the valve close faster, which may reduce slam in some systems. They can also be suitable in more orientations, depending on model.
Cracking pressure matters. If your system has low differential pressure at normal flow, a spring that’s too stiff can quietly restrict flow and waste energy.
Dual-plate check valves typically use two hinged plates and are often built in wafer form. The design is compact, which is valuable in crowded pipe racks or retrofits.
Compact footprint, typically reasonable pressure drop for the space, and a common option in larger pipe sizes.
Noise and chatter are system problems as much as valve problems. Placement, flow profile, and velocity still decide the outcome.
Pick the design that matches your operating reality, not the one that looks best on a datasheet.
With the common types in mind, the next step is selection. A good checklist keeps you from ordering a valve that “should work” on paper but behaves poorly at normal flow.
In water, think about corrosion, debris, and transient events. If you’re in infrastructure, also consider maintenance access and how often the line will be cycled.
In hydraulic or oil service, cleanliness and viscosity influence how the valve opens and closes. A valve that’s stable in water can behave differently in thicker fluids.
In gas service, closing stability can be more sensitive, and acceptable leakage may be lower depending on the process. Don’t treat “gas” as a minor variation of liquid.
Steam/condensate selection depends on what phase is actually at the valve at each operating point. Temperature and erosion risk move to the front of the line here.
If you have solids, ask where they will settle. A design with narrow guiding surfaces may stick. A design with a forgiving seat may last longer—but only if you can service it.
Use max operating pressure, but also account for surges. In pump systems, the “normal” pressure may be calm, while transient pressure events do the real damage.
Don’t only check the maximum temperature. If you have frequent cycling, materials expand and contract repeatedly, and that can affect sealing and wear.
If the system can pull vacuum or back-siphon, confirm the valve can seal and survive those conditions. It’s a common reason “standard” valves underperform.
Many problems start because the valve spends most of its life at low flow. If the element hovers near the seat, you can get vibration, noise, and accelerated wear.
Pressure drop isn’t just “lost head.” It can change pump duty, shift operating points, and add ongoing energy cost. Compare pressure-drop data (Cv/Kv) for realistic flow rates.
Chatter is often a symptom of mismatch: oversizing, poor placement, pulsing flow, or insufficient differential pressure. If you hear it, treat it as a design signal.
Stainless steel is often chosen for corrosion resistance and broad compatibility, but grade and media details still matter—especially if chlorides are present.
Carbon steel is common in industrial service where corrosion is controlled and pressure/temperature requirements are higher. Verify coating or corrosion allowances if relevant.
PTFE seats or seals can help in certain chemical services, but always confirm temperature limits and mechanical constraints for your specific design.
EPDM and NBR are common elastomer choices. The right pick depends on the media and temperature range; a seal that’s perfect in water may be wrong in oil, and vice versa.
If you can answer those questions, most selection discussions become straightforward.
After selection comes sizing. This is where many systems drift into “it works, but it’s annoying.” A correctly sized valve opens fully enough to be stable at normal flow without creating an unnecessary pressure penalty.
Write down minimum, normal, and maximum flow rate, along with temperature and pressure. If you have a pump curve or process cycle, include that too.
Don’t size a swing check the same way you size a spring check. The internal geometry changes how the valve behaves at low flow and how quickly it closes.
Use available Cv/Kv or pressure-drop curves at your normal flow. If the pressure drop is high, look at a different design or a different size—then re-check low-flow stability.
High velocity can raise noise and wear; very low velocity can promote unstable closure. The “right” range depends on media and system, so use your project’s engineering guidelines where available.
Oversizing is the classic error. The valve looks safe because the line size matches the valve size, but the valve may run partly open most of the time. That’s where chatter and seat damage can start.
Undersizing can create excessive pressure drop and high velocity, which can increase noise and shorten service life. It can also shift pump operation in ways you didn’t intend.
If your system frequently operates at minimum flow, check cracking pressure and stable opening behavior. A valve that behaves at max flow might misbehave every other hour of the day.
The goal is simple: stable opening, predictable closing, and acceptable pressure drop at the flow you actually run.
Even a perfectly selected valve can perform poorly if it’s installed in a bad spot. This is where small, practical choices—orientation, spacing, and cleanliness—decide whether the valve stays quiet for years or becomes a recurring issue.
It’s basic, but it still happens: confirm the arrow matches the intended flow before you tighten everything down. If the valve is installed backwards, you’ll see immediate restriction—or a valve that never seals.
Many designs work well horizontally, but some need gravity to help the closure element settle properly. Always follow the manufacturer’s orientation guidance for the specific product.
Vertical mounting can be fine, but it changes how the element moves and how debris settles. If you’re installing vertical, confirm whether the design expects upward flow, downward flow, or both.
Check valves are often placed on pump discharge to prevent reverse rotation and backflow. Keep in mind that closing events are stronger near pumps, so selection and sizing are extra important here.
Water hammer is driven by rapid changes in velocity. A check valve that closes abruptly can contribute to a pressure surge, especially during pump trips. If your system is sensitive, treat valve closure dynamics as part of the design—not an afterthought.
If you can’t access the valve, you won’t maintain it. And if you don’t maintain it, small leaks become system problems. Design for inspection space from day one.
New piping often contains debris (scale, welding residue, grit). If your valve seat gets damaged during first start-up, it may never seal properly again.
If the valve chatters during commissioning, you’ve learned something valuable. Address it right away—often by correcting sizing assumptions, stabilizing flow, or adjusting placement.
Record model, size, body/trim/seal materials, cracking pressure (if applicable), and service conditions. That turns future troubleshooting from guesswork into a quick checklist.
A calm commissioning usually predicts a calm service life.
If a check valve is acting up, the first step is to treat the symptom as a clue. Most failures repeat the same pattern: debris on the seat, mismatch at low flow, or mechanical wear from repeated transients.
Leakage usually comes from seat damage, debris, misalignment, or an element that can’t return cleanly to the seat. In gas service, “small leakage” can also be a design/expectation issue—confirm what leakage is acceptable for the system.
Chatter often points to low differential pressure at normal flow, oversizing, or turbulent flow near the valve. It’s commonly triggered by pulsing pumps or frequent cycling.
Sticking is a typical outcome in dirty media or where corrosion products build up. Guided designs can be more vulnerable, but any valve can stick if deposits are heavy enough.
Seat wear accelerates with high velocity, solids, and slam events. If a valve keeps failing early, look upstream: the system may be asking the valve to do more than it can comfortably do.
If the issue appeared after a known contamination event or just after commissioning, cleaning and flushing may restore sealing—provided the seat isn’t damaged.
Replace when the seat or body is damaged, when chatter is persistent despite system fixes, or when the valve design is mismatched to the media (for example, solids in a design that can’t tolerate them).
You don’t need a complicated plan. A short, repeated check for abnormal noise, unstable pressure, and process upsets catches most problems early.
Water hammer is a pressure surge caused by sudden changes in flow velocity—often pump trips, quick valve closures, or rapid demand changes. It’s a system event, not a single-component event.
Some check valve designs aim to reduce slam by closing more smoothly or faster under certain conditions. That can reduce peaks, but it won’t eliminate water hammer if the root cause is elsewhere.
Start by confirming velocities and transient events, then review placement and closing behavior. If the consequences are serious, treat transient analysis as part of engineering scope.
Most fixes are either “clean and protect” or “reselect and stabilize.” The right choice depends on the cause.
Last step: procurement. In Norway and across Europe, projects often mix client specs, industry norms, and supplier documentation. The safest path is to ask for the documents that prove the valve fits your service, then verify the details against your project requirements.
Ask for size, type, materials (body/trim/seals), pressure/temperature limits, intended orientation, and pressure-drop data. If it’s a spring check, request cracking pressure options.
If the valve is critical, ask what testing is performed and what documentation is available. Don’t assume every product line has the same test package.
For higher-risk service, ask what traceability exists (material certificates, heat numbers, documentation scope). If traceability matters, make it explicit in the purchase requirement.
“Designed to meet” is not the same as “tested and certified to.” If you require a specific standard, ask for the exact documentation that supports it and confirm it aligns with your project’s acceptance criteria.
Over-specifying can slow delivery and increase cost without improving reliability. If you want a robust result, focus on what affects performance: correct type, correct sizing for normal flow, suitable materials, and verified ratings.
Yes, but gas behaves differently than liquids. Closing stability at low flow, acceptable leakage, and the right type (often spring-assisted) matter more. Always verify suitability for the specific gas, pressure, and temperature.
A check valve (NRV) is a one-way valve that opens under forward pressure and closes when flow slows or reverses, helping prevent backflow in systems with water, oil, gas, or steam.
Media drives material choice, sealing, and how the valve closes. Water often means debris and water hammer risk, steam means temperature/erosion, gas can mean more chatter risk, and particles may require a more debris-tolerant design.
Cracking pressure is the minimum upstream pressure needed to start opening the valve. It matters most in low-flow or low-differential systems—too high can restrict flow; too low can contribute to instability in some setups.
They can help reduce slam in certain systems, but water hammer is a system-level transient. Correct sizing, placement near pumps, velocity control, and sometimes “soft-close/silent” designs are usually required.
Not always. If the main driver is pump trip, fast downstream closure, or rapid demand changes, you may need additional measures beyond a check valve—think system transient mitigation, not only component selection.
Common construction use cases include temporary water systems, dewatering setups, pump discharge lines, and any installation where preventing backflow protects equipment or keeps the line primed.
They’re used to prevent reverse flow in pumping stations, distribution networks, and treatment-related piping. Selection typically prioritizes stable operation, service access, corrosion resistance, and managing surge events.
It depends on the application and project requirements. Verify by requesting documentation (datasheet, declarations, test reports, and referenced standards) and matching it to the project spec—avoid relying on generic marketing claims.
It’s a check valve used in a hydraulic circuit to allow flow in one direction and block reverse flow, helping maintain pressure and protect components during load changes or pump shutdowns.
A check valve is designed to permit fluid flow in only one direction. The internal mechanism typically consists of a disc, ball, or another guided element, which is held in place by a spring against the valve seat. When system pressure is insufficient to open the valve, or when negative pressure is present, the valve remains closed. However, once adequate positive pressure is applied, the valve opens, allowing the fluid to move past the disc and continue through the system.