Designed to prevent the backflow of contaminated water into clean water supply lines, check valves are a common part of water systems. But while they’re effective at keeping wastewater from leaking into drinking water, they can also fail under certain circumstances and cause problems.
While many types of check valves use metal construction, rubber materials offer a number of advantages for modern applications. They’re also easier to maintain, which can help users avoid costly downtime and replacement.
The first consideration for any check valve is selecting the right material for its application. Choosing the wrong material can lead to issues like corrosion or leakage. It’s also important to choose a check valve that’s suited for the system fluid.
For example, saltwater can corrode metal check valves and make them less durable. In addition, slurries with large amounts of solids can cause metal check valves to wear out faster than they should.
In situations where there are a lot of solids in the flow, rubber check valve are a better choice than traditional metal check valves. This is especially true in wastewater and stormwater systems where the pumped fluid is typically a combination of raw sewage and sludge.
Another advantage of rubber check valves is their ability to handle temperatures up to 400 F. They’re able to handle a wide range of thermal applications thanks to the specialized elastomers that they’re made from.
They’re also great for systems that need to handle high- or low-temperature fluids. The specialized elastomers used in Proco’s check valves are designed to handle these temperatures without losing shape or breaking down.
Compared to traditional metal check valves, these rubber devices are also much quieter and operate silently to protect the environment. They can also be installed in areas where noise may be an issue, such as schools and hospitals.
To combat the slam that can occur when a check valve closes quickly, manufacturers recommend choosing a slower closing type. This is done by adding ancillary equipment to the valve, such as hydraulic dampers.
The dampers reduce the kinetic energy from the flowing fluid turning into pressure as it closes, which can help to eliminate check valve slam. The slower closure is also helpful in reducing the risk of slam damage to the upstream equipment such as pumps.
In many pumping applications, check valve slam can increase the likeliness of pressure surges to occur. This is because if the check valve closes quickly, it causes the kinetic energy from the flow to turn into pressure, which can slam against the upstream equipment. This can be very damaging to the pipes and cause significant noise.
To minimize this problem, it’s critical to choose a check valve with the correct Cv value. The Cv value determines the minimum operational pressure the valve must open to fully seal. In some cases, the valve may only partially open if it has a lower Cv value. This can result in a variety of problems, such as increased resistance and pressure drop, and even flutter.