Ball Valve vs Plug Valve: What’s The Main Difference?

Plug valves and ball valves are both 90° rotation valves, and their structures are similar. Understanding the detailed differences between plugs valve and ball valves can help us choose the appropriate valve.

Differences Based on Various Factors.

Design and Structure

the ball valve is a modification of the plug valve and is a special type of the latter. Plug valves use a conical or cylindrical plug to control fluid flow through side passageways, while ball valves have a spherical disc with a circular bore channel.

The design standard for plug valves is API 599, while the design standards for ball valves are API 6D or API 608.

Sealing

The plug valve provides better sealing properties due to its larger sealing surface but requires more torque during operation. While ball valves have a smaller sealing surface, making them easier to regulate and operate.

Applications

Plug valves are commonly used in medium or low-pressure and low-temperature environments, whereas ball valves are versatile and suitable for various systems, including high-pressure and extreme operating conditions.

Cost

Plug valves cost less than ball valves. Plug valves have a simple design, which makes them less expensive to produce and install.

Lifespan

Generally, ball valves last longer than plug valves due to their lower torque and fewer contact areas with the medium, which reduces wear and tear.

Maintenance

Plug valves have a simple construction and few moving parts, making them easier to maintain compared to ball valves. Accessing and cleaning the internals of ball valves can be more challenging.

Flow Regulation

Due to the cylindrical shape of the plug valve’s flow passage compared to the spherical shape of the ball valve’s flow passage, plug valves have higher flow resistance than ball valves. This makes plug valves suitable for low-flow and highly viscous media.

Size and Installation

Plug valves are more compact and have a lower footprint, making them suitable for smaller applications, while ball valves are more widely used in larger systems.

Lubrication

When the plug valve has a large diameter, the plug must be installed upside down, with the head of the plug facing downward. Due to the effect of gravity, this can cause a decrease in sealing performance, which needs to be compensated for by applying grease to ensure proper sealing.

Lubricated plug valves have a metal plug with a lubricant chamber, reducing friction and enhancing corrosion resistance, whereas ball valves do not require lubrication.