Verder

of the disk determines the shut-off characteristics of the valve. The swing check valve mechanism is commonly used in the flapper valve installed in flush toilets. It is used in sanitary drainage systems as a backwater valve to prevent flooding by sewage water when there is heavy rainfall. A wafer check valve is quite similar to a swing check valve. It is simple in design and can be used in tight spaces. The main difference is that they are constrained by flanges that hold them in place. It means that the disk cannot be fully opened, compared to a swing valve with a valve body that allows full opening. The wafer check valve is popularly used when the flow is not an issue, or if there is limited space for valve installation. A diaphragm check valve has an elastic membrane as the sealing mechanism, in a normally closed position. When the pressure upstream of the valve is higher than downstream, the check valve opens and allows fluid flow. Otherwise, the check valve remains closed. They are typically used in low-pressure systems with plastic piping.

How to select a check valve?

Selecting a check valve is an integral part of process design. While different types have the same functional purpose – which is to allow flow in only one direction – each type is often unique to a specific application. What check valve should I use for my application details what should be remembered when selecting a check valve. Here is a quick overview of what to consider when choosing a check valve: • The possibility of water hammer • Chemical compatibility • Non-slam characteristics • Cost-benefit analysis • The pressure drop across the valve • Operating pressure and pressure differential in the process • The speed of the fluid • Installation orientation

Conclusion

Check valves are simple devices that operate without intervention, and they achieve an essential function of preventing reverse flow in a process. There are several types of check valves for different applications in industrial processes. They are easy to install, maintenance-free, and durable. The robustness of check valves makes them quite versatile for use regardless of fluid type, fluid phase, operating condition, orientation, and operation frequency.

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