Structure, Function, and Operating Principle

1. What Is a Breather Valve?
   A breather valve, also known as a pressure-vacuum relief valve (PVRV), is a safety device that protects storage tanks from explosion or collapse caused by pressure differences. It is typically installed on top of storage tanks for fuels, chemicals, LPG, or gases.

   

2. Structure of a Breather Valve
   A breather valve consists of the following main components:

• Valve Body: Made from steel, stainless steel, aluminum, or cast iron, designed to withstand pressure and harsh environments.

• Valve Cap: May include or exclude a flame arrester.

• Spring or Weighted Disc: Regulates the valve’s opening pressure.

• Sealing Gasket: Ensures gas or vapor only escapes when the set pressure is reached.

• Flame Arrester (Optional): Prevents flames from entering the storage tank.

  

3. Functions of a Breather Valve

• Releasing Excess Pressure: When internal tank pressure exceeds the set threshold, the valve opens to release gas, preventing tank explosion.

• Drawing Air into the Tank: When internal pressure drops below safe levels, the valve opens to let air in, preventing tank collapse due to vacuum.

• Preventing Solvent Vapor Loss: Protects the environment and reduces fuel loss.

• Integrated Flame Arrester: Safeguards tanks from fire or explosion caused by sparks or sudden pressure surges.

4. Operating Principle of a Breather Valve
   The breather valve operates based on the pressure differential between the inside of the tank and the external environment:

• When internal pressure exceeds the set point: The force on the valve disc surpasses the spring force, causing the valve to open and release gas. When pressure returns to a safe level, the valve automatically closes.

• When internal pressure drops (vacuum forms): External atmospheric pressure is higher than inside the tank, causing the valve to open and allow air in. Once pressure is balanced, the valve closes.

  

5. Types of Breather Valves

• Pressure-Vacuum Relief Valve: The most common type, protecting tanks from both overpressure and vacuum.

• One-Way Breather Valve: Allows airflow in only one direction, either in or out.

• Breather Valve with Flame Arrester: Used in flammable or explosive environments.

• Emergency Breather Valve: Activates during sudden overpressure incidents.

  

6. Applications of Breather Valves

• Oil and Gas Industry: Installed on fuel, oil, LPG storage tanks to control pressure.

• Chemical Industry: Protects chemical storage tanks from volatile substance loss.

• Food and Pharmaceutical Industry: Controls vapor and protects storage environments.

• Compressed Air and Gas Storage: Ensures safety in high-pressure systems.

Breather valves are essential devices that maintain safe pressure levels in liquid or gas storage systems, preventing explosion risks and fuel loss.

Contact: PHUC MINH TECHNICAL CO., LTD. for reliable, high-quality industrial valve solutions.
Email: duong@pm-e.vn
Cellphone/Zalo: +84 902 499 190
Address: 92/38, Street No.12, KP18, Binh Hung Hoa Ward, Binh Tan District, Ho Chi Minh City, Vietnam.