Plug Valve vs Ball Valve: A Quick Comparison
Plug Valve vs Ball Valve: An Overview
In industrial flow control and in industrial piping systems, the valve is the focal point of interest of the guiding, the isolating, and the controlling of gases and liquids. Two of the most popular valves utilized in industry are the plug valve and the ball valve. Although both have the same overall purpose—to allow or to shut off flow—their operation, construction, application, and performance can be vastly different.
We at Speciality Valve offer industries such as oil & gas, petrochemical, water treatment, and power generation a variety of high-performance valves. In this blog here, we will provide you with a detailed overview of plug valves and ball valves so that you can make a logical choice regarding which one best fits your application.
What is a Plug Valve?
A plug valve is a quarter-turn rotary valve featuring a cylindrical or conically tapered plug for controlling flow. The plug features a centre hollow passage, and fluid flow can be achieved when the plug aligns with the pipeline. A 90-degree rotation of the plug closes the passage and impedes the flow.
Plug valves are mostly most frequently employed since they are easy, space-saving, and quick in action, particularly where operation or shutting down at intermittent time intervals needs to be implemented in systems.
What is a Ball Valve?
Ball valve is a quarter turn valve but one with spherical disc (ball) which has a hole (bore) extending through its middle. Through alignment of bore to pipeline, flow is started; by a 90 degree turn, solid part of ball closes off flow.
Ball valves are especially known for tight shutoff, long life, and smallest pressure drop, thus used everywhere in virtually every industry.
Chief Plug Valve to Ball Valve Differences
We now look at plug and ball valve differences in design, when operating in use, operation, and function.
1. Design and Shape
Plug Valve:
- Utilizes a taper or cylindrical plug as the seal device.
- Plug rotating inside the valve body to open or close off the fluid passage.
- Comprised of small inner elements as well as compact size.
Ball Valve:
- Uses a ball plug having a central orifice inside.
- Seats trap the ball and turn to control flow.
- Can be two-piece, three-piece, or top-entry body for maintenance.
Plug valves are smaller in size and lesser in design range, whereas ball valves are larger in design range.
2. Working and Regulation of Flow
Plug Valve:
- Is highly suitable for on/off service.
- Certain designs can throttle but are less accurate than ball valves.
- Easy to operate and high speed with a quarter turn.
Ball Valve:
- Has better shut-off with low efficiency of torque.
- All most well suited for throttling as well as on/off under restraint.
- Maintains steady performance over many years of life.
Shut-off and life are optimum in ball valves, but repetition of operation to facilitate speedy operation is optimum in plug valves.
3. Leakage and Sealing
Plug Valve:
- Utilizes lubricated seals or elastomeric sleeves to provide tight shut-off.
- Shows leakage after some time unless lubricated every now and then (in lubricated designs).
Ball Valve:
- Typically offers bubble-tight sealing.
- Soft-seated ball valves offer very little leakage even in high-pressure systems.
Ball valves typically offer superior sealing and protection against leakage, especially for safety applications.
4. Maintenance and Life Span
Plug Valve:
- Simple structure and few components make them free from maintenance.
- Need frequent lubrication in lubricated designs.
Ball Valve:
- Soft-seated ball valves will be prone to degrading with time if used in high-cycle or abrasive service.
- Repair can be more complex by type (e.g., 3-piece for service).
Plug valves are simpler to repair; ball valves are stronger but may need service in specific environments.
5. Suitability for High Temperature and Pressure
Plug Valve:
- Is acceptable for high pressure and temperature but usually in less severe service.
- Metal-seated plug valves excel in extreme conditions.
Ball Valve:
- Most suitable for high-pressure and high-temperature systems.
- Comes in metal-seated types for heavy-duty service.
Ball valves are best suited for high-temperature, high-pressure, and abrasive media applications.
6. Applications
Plug Valve:
- Most suitable for wastewater, slurry, and low-pressure application.
- Utilized in chemical plants, pulp & paper, and fuel systems.
Ball Valve:
- Utilized in oil & gas, petrochemical, HVAC, and marine services.
- Applied where bubble-tight shut-off and high-cycle operation are necessary.
Employ plug valves for economy and convenience; ball valves for duty-critical performance.
Advantages and Drawbacks
Plug Valve Advantages:
- Simplistic and easy to use.
- Compact and space-efficient.
- Rapid quarter-turn opening and closing.
- Less expensive in most uses.
- Can be used in dirty, viscous, or slurry-type media.
Drawbacks:
- Would need to be lubricated.
- Less accurate in throttling.
- Susceptible to wear and leakage in the long run on lubricated types.
Ball Valve Advantages:
- Good shut-off.
- Low pressure drops.
- Low maintenance (soft-seated types).
- May be installed in high-pressure and high-temperature applications.
- Suitable for control and automation.
Drawbacks:
- Expensive compared to plug valves.
- Bigger in size and weight.
- Soft seats may be eaten in eroding environments.
How to Decide Between Plug Valve and Ball Valve?
Finally, the choice is determined by your system operation requirement, fluid, pressure/temperature range, and cost.
Select a Plug Valve if:
- Your application is handling slurries, dirty or viscous liquids.
- You require a low-cost, space-saving design.
- You require high frequency and fast valve operation.
Select a Ball Valve if:
- Bubble-tight shut-off is required.
- Your application is pressure or temperature high.
- Accuracy and long life are essential.
- You will automate the valve.
Ball valves and plug valves are both good, established choices based on application. Plug valves provide compactness and simplicity, whereas ball valves are recognized for good seal, long life, and suitability to high-performance applications. We produce and provide top-quality plug and ball valves in different materials, pressure classes, and sizes to meet your industry requirements. Our engineering specialists are here to assist you in selecting the most suitable valve solution for your application.
Having trouble selecting the correct valve? Contact Speciality Valve today and speak with our specialists, who will provide you with long-lasting, quality products.
