EVA UPVC Spring Check Valve, also known as a Non-Return Valve (NRV), is a type of valve that uses a spring mechanism to automatically prevent backflow in a piping system. It's commonly used in various applications like water and wastewater systems, industrial processes, and swimming pools. The valve opens when the liquid or gas pressure exceeds the spring's resistance, and it closes automatically when the flow reverses or stops. 

Here's a more detailed explanation:

Key Features:

• Material:

Typically made of UPVC (Unplasticized Polyvinyl Chloride), which is lightweight, resistant to chemicals and abrasion, and suitable for potable water. 

• Spring Mechanism:

A spring is used to hold the valve disc in the closed position until the fluid pressure overcomes the spring force. 

• Automatic Operation:

The valve opens and closes automatically based on the fluid pressure, eliminating the need for manual operation. 

• Installation:

Can be installed vertically or horizontally, depending on the specific application. 

• End Connections:

Available with various end connections like socket, threaded, or flanged. 

How it Works:

• The valve utilizes a spring to hold a disc or poppet in a closed position, blocking flow.
• When fluid flows in the intended direction with sufficient pressure (known as "cracking pressure"), it overcomes the spring's resistance and pushes the disc open, allowing flow.
• If the flow stops, slows, or attempts to reverse, the spring immediately pushes the disc back against the valve seat, creating a tight seal and preventing backflow

Applications:

• Water and Wastewater Systems:

Used to prevent backflow in pipelines, pumps, and other equipment.

• Industrial Processes:

Used in various industrial applications where backflow prevention is crucial.

• Swimming Pools and Spas:

Used to maintain water circulation and prevent backflow into the pool or spa.

• Other Applications:

Can be used in plastic industrial applications and water treatment systems. 

Advantages:

• Effective Backflow Prevention: Provides a reliable way to prevent backflow in various systems.
• Automatic Operation: Requires no manual intervention, making it convenient for many applications.
• Versatile Installation: Can be installed in both horizontal and vertical orientations.
• Durable and Resistant: UPVC material offers good chemical and abrasion resistance.