Control valves are important for production setups where the concerned person must check, control and change the fluid flow from various piping areas. These valves are of two types – ball valves and plug valves. Even though some differences are present in their functioning and structure, both have some similarities in their purposes and are used interchangeably in different applications.
As we move further we will look into the five main basics between plug valves vs ball valves based on which we differentiate between both types of valves.
Key Differences Between Plug Valve And Ball Valve
Whether it is chemicals, gas, oil, petroleum refining, sewage, wastewater, or beverage or food industries, control valves have various uses in many industries. The right selection ensures the efficiency and safety of the systems. Thus, it is vital to know the differences in their functionalities, structure, and other aspects like maintenance and costs.
It’s easy to differentiate these valves based on their structure, resistance, quick opening, closing, etc. Additionally, rotating them is difficult and they need some time for grinding while maintaining. Thus, the main structural difference between ball and plug valves is that the latter is easy to adjust while cutting off. A plug valve has a more sealing surface than a ball valve. The plug valves are plunger-shaped or closed rotary valves, which are possible to open or close after rotating 90 degrees for connecting or separating the channel opening on the valve plug and the valve body.
These feature a cylindrical or a conical tapered disc to control the fluid movement from many paths going sideways along the plug. Their shapes are responsible for light construction making them ideal for shutting on and off the medium and diverting. However, based on the application nature and resistance to erosion, it is also possible to use for throttling.
Both ball and plug valves are quarter-turn valves that can easily open and close after turning the actuator to 90 degrees. Their primary uses are to shut off and seal operations. However, the plug valve sealing surface is more than that of the ball valve. While it might mean more sealing capabilities, it also equals higher effort and more torque while functioning.
Because of their lightweight and torque-free operation, the ball valves are relatively simpler to function than plug valves. Although a small sealing surface can mean low-performance sealing, advancements in chemical sealants and sealing injections help address such faults.
Differences In Operational Principles
Ball valves come from plug valves with a 90-degree rotation, but that depends mostly on the ball or plug with a circular hole or a passage on its axis. During the 90-degree rotation, it cuts off the flow as a sphere at the inlet and outlet.
The plug valve is available with a conical plug whose body surface is formed from conical pressure. Here, the upper parts are sealed with a PTFE sheet in between the body gap and the plug. Plug valves are easy and cost-saving options as they mostly come with the handle fitted at the outside end rather than using the bonnets present in other valves.
The unrestricted flow and more surface area from plug valves ensure better control flow than the ball valves. However, the plug valve’s main benefit is limited. The surface sealing of the plug valve is more than the ball valve, ensuring better sealing benefit on the plug valve face, but it also makes it less operational with low flexibility due to higher torque.
The sealing performance of ball valves ensures that it meets the most needs of all the practical applications. Ball valves are perfect because of their technological improvements in machining with accuracy and the sealing materials they use. All these features make them capable of a wider scope of applications.
Differences In Costs
The plug in the plug valve is covered wholly by the PE molding, saving the valve body and plug from any wear and tear. It is possible to repair and update the plug valve by changing the top seal and bushing, which lets you meet service demand of 300°C. With this temperature range yuo get many benefits over the conventional metal hard-sealed ball valves.
PE-coated ball valves have more benefits over other metal-seated ones that are hard-sealed in a similar temperature range. Furthermore, only the flange and top face of the plug need processing. A single stage is indeed for casting its other sections, and the interior doesn’t need further processing. Thus, while manufacturing alloys and other exotic materials, plug valves offer such economic benefits over the ball valves.
Between both, the plug valve has a lower processing allowance offering better pricing benefits. These were the prominent differences between both ball valves and plug valves. The ball valve has a little bit less sealing effect, but it offers more diameter. With better technology, the ball valve’s sealing effect gets better. Therefore, plug valves are ideal to use on occasions with strict requirements for sealing, but they have low caliber. Ball valves are handy for situations where a strict sealing effect is not needed and a large caliber comes into play.