What device helps to prevent backflow in plumbing systems?

The check valve is specifically designed to prevent backflow in plumbing systems. It allows fluid to flow in one direction only, which is crucial for maintaining the integrity and safety of the plumbing system. When fluid flows in the intended direction, the check valve opens, allowing passage. However, if there is a reverse flow or a drop in pressure in the system, the valve automatically closes to prevent the backflow of water or other substances, which could lead to contamination or damage.

The air gap is also a method of preventing backflow by creating a physical separation between the potable water supply and the potential source of contamination, but it functions differently compared to a check valve. A pressure regulator is used to maintain a consistent water pressure within the plumbing system but does not prevent backflow. Similarly, a flow meter is designed to measure the flow rate of water, but it does not serve the function of preventing backflow. The check valve is a critical component in plumbing systems where the direction of flow needs to be carefully controlled to ensure safety and efficacy.