Double Block And Bleed Valve

Double block and bleed valve, also known as a DBB valve, is a type of valve that provides positive isolation in a pipe system. It consists of two block valves and one bleed valve, all connected in a single unit. The main function of a double block and bleed valve is to ensure that both upstream and downstream sides of the valve are isolated from each other.

There are different types of double block and bleed valves, including the floating type and the trunnion type. The choice of valve type depends on the specific application and requirements.



Double block and bleed (DBB) valves are an essential component in industries where critical fluids need to be isolated. The floating type DBB valves have two floating balls that seal against two seat rings, providing a double barrier against the fluid flow. These valves are designed to prevent leakage in both the upstream and downstream directions, ensuring maximum safety. The floating balls are mounted on a stem, allowing them to move freely and create a tight seal when closed. When the valves are open, the fluid flows through the cavity between the balls, effectively blocking any potential leakage. Double block and bleed valves are commonly used in high-pressure systems and are preferred in applications where complete isolation is necessary. With their reliable performance and ability to minimize the risk of leakage, floating type DBB valves are a crucial component in maintaining the integrity and safety of fluid systems in various industries.


The double block and bleed trunnion type valve is a type of valve that provides a double block and bleed function, meaning it can block the flow in both directions and also allow for the release of any trapped fluid between the two blocks. This valve is commonly used in applications where safety and reliability are crucial, such as in the oil and gas industry. The trunnion type design refers to the fact that the valve has trunnions or protrusions that support and hold the ball in place during operation. These trunnions allow for smooth operation and reduce the torque required to open and close the valve. The double block and bleed feature of this valve provides an additional layer of safety by ensuring that the fluid is fully isolated from the system before any maintenance or repair work is carried out. Overall, the double block and bleed trunnion type valve is a reliable and efficient solution for critical applications requiring maximum safety measures.

Components of a DBB VALVE

Valve Body

The valve body is the main housing of the DBB VALVE. It provides the structural support and contains the internal components.

Isolation Valves

The isolation valves are the two block valves in the DBB VALVE. They are responsible for isolating the upstream and downstream sides of the valve.

Bleed Valve

The bleed valve is the third valve in the double block and bleed valve. It serves as a vent or drain valve to release any trapped fluid or pressure in the cavity between the block valves.

Advantages of Double Block and Bleed Valves

Enhanced Safety

One of the main advantages of double block and bleed valves is enhanced safety. By providing positive isolation, they minimize the risk of leakage and ensure the safe operation of the system.

Space and Cost-Saving

Double block and bleed valves offer space and cost-saving benefits. Instead of installing separate valves for isolation and bleed, a single unit can perform both functions, reducing the overall footprint and cost of the system.

Ease of Maintenance

With a double block and bleed valve, performing maintenance is simpler and more efficient. Instead of having to shut down the entire system or install temporary bypasses, the isolation valves can be closed while the bleed valve is used to drain any fluid or pressure, allowing for maintenance work to be done on the specific section of the system.

Applications of Double Block and Bleed Valve

Oil and Gas Industry

In the oil and gas industry, double block and bleed valves are commonly used for pipeline maintenance and repair. They allow for the isolation of different sections of the pipeline, ensuring that work can be done on one section without interrupting the flow of oil or gas in other sections.

Petrochemical Industry

The petrochemical industry also relies heavily on double block and bleed valves. They are used in the transportation and storage of hazardous chemicals, providing a reliable means of isolating different sections of the system for maintenance or in the event of a leak.

Chemical Industry

Similarly, the chemical industry uses double block and bleed valves to ensure the safe handling of various chemicals. These valves provide a high level of protection against potential leaks or contamination, allowing for the efficient and safe operation of chemical processing plants.

Choosing the Right Double Block and Bleed Valve

Factors to Consider

When selecting a double block and bleed valve, several factors need to be considered. These include the pressure and temperature requirements of the system, the type of fluid being transported, and the specific application of the valve.

Common Challenges and Solutions

One common challenge when using double block and bleed valves is the potential for leakage between the valve sealing surfaces. This can be mitigated by selecting valves with high-quality sealing materials and proper maintenance and installation procedures.

Maintenance and Safety Measures

Regular Maintenance

To ensure the continued performance of double block and bleed valves, regular maintenance is necessary. This includes periodic inspection, cleaning, and lubrication of the valve components.

Safety Procedures

It is important to follow safety procedures when working with double block and bleed valves. This includes proper training on valve operation and maintenance, as well as the use of personal protective equipment.


For inquiries on purchasing a double block and bleed valve, please contact our customer service department. Our knowledgeable staff is ready to assist you with any questions or concerns you may have. We offer a wide range of high-quality valves suitable for various industrial applications.


Double Block and Bleed Valve for Precision Flow ControlDouble Block And Bleed Valve
× How can I help you?