Control valves are an essential component of any manufacturing setup that requires monitoring, controlling, or manipulating the flow of a fluid medium through various piping areas of a system. Control valves are classified into two types: plug valves and ball valves. Despite some differences in their overall structure and operation, both valves serve similar functions and are frequently used interchangeably in various applications.


Key Features of Plug Valve and Ball Valve

Control valves are used in various industries, including oil and gas, chemicals, petroleum refining, wastewater and sewage, and even food and beverage. Choosing the right type of control valve is critical to ensuring the safety and efficiency of your systems. As a result, it is critical to comprehend their structure, functionalities, and other factors such as cost and maintenance.


  1. Structure

Here’s a closer look at the two types of control valves:


Plug Valves

A plug valve, which has a conical tapered or a cylindrical disc, regulates fluid flow through one or more sideways passages in the plug. The hollow passage aligns with the flow when the valve is open, allowing the fluid to flow freely. A 90-degree rotation closes the valve and realigns the plug, preventing the flow.


The plug valve is small and simple, and it is used to cut, distribute, or change the flow of media. Its primary applications are in medium or low-pressure, low-temperature settings, though certain plug valves can also be used in high-temperature settings.


Gas plug valves come in four different styles, including lubricated, non-lubricated, expandable, and eccentric, in addition to a two-way, three-way, and multi-point port openings.


Ball Valves

The ball valve is a modified plug valve with a spherical disc and a circular bored passageway. The hole in the disc is known as the port. The valve is open when the port aligns with both ends of the valve, and the medium flows through it. The flow is stopped when the port is perpendicular to the valve's ends.


Ball valves are suitable for a wide range of systems due to their compact structure, ease of operation and maintenance, and compatibility with water, natural gas, acids, and solvents. Ball valves are well suited for harsh media such as hydrogen peroxide, methane, ethylene, or oxygen. While traditional gas shutoff ball valves are best suited for open and close functionality, more advanced or customized versions can also provide flow control and throttling.


Ball valves come in four different types of construction:

  • Full port or full bore ball valves have an oversized ball with the same hole and pipeline size, resulting in lower friction loss. Because the valve is more expensive and larger, it is typically used only where free flow is required, such as pipelines requiring pigging.

  • Reduced bore ball valves have a slightly smaller ball than the pipe size of the valve. This reduces the flow area and, as a result, increases the flow velocity.

  • With a v-shaped ball, a V-port ball valve allows for a more controlled opening and closing of the orifice, resulting in a near-linear flow.

  • A trunnion ball valve has additional mechanical anchoring that holds the ball or disc between the stem and the shaft. This type of ball valve is useful in applications where higher pressure or larger valves are required.


  1. Function

Plug and ball valves are quarter-turn valves that open and close with a quick 90-degree turn of the actuator. Their primary application is for sealing and shutting down operations. The sealing surface of a plug valve, on the other hand, is significantly larger than that of a ball valve. While this results in better sealing qualities, it also increases torque and effort during operation.


Ball valves are less difficult to operate than plug valves due to their torque-free operation and lightweight. Although their smaller sealing surface may imply poor performance, advances in seal injections and chemical sealants have assisted in overcoming this shortcoming.


  1. Maintenance

Both types of control valves require routine maintenance to function properly. Plug valves are relatively easier to maintain due to their simple design and lack of moving parts. Furthermore, you can easily remove and clean the plug and clean the rest of the valve body.


Ball valves are more difficult to clean because the ball or disc is located deep within the valve, making access difficult. The ball valve's body cavity may accumulate particles from the medium over time, complicating cleaning and maintenance.


In general, plug valves are less expensive to operate than ball valves. The plugin, the plug valve, fits under the bushing, keeping the valve body and plug free of wear. Simply replacing the bushing and top seal is enough to keep the valve's optimum function and long-term service requirements current.


  1. Application

Plug valves are ideal for applications involving mud, slurries, or sewage due to their larger surface area and unrestricted flow. Fortified plug valves provide tight seals when dealing with hard or corrosive mediums. Because of their simple structures, ease of operation and maintenance, and anti-corrosion properties, they are a reliable shutoff option for most critical applications.


Ball valves are a popular choice for a wide range of automated applications, such as gas feed lines, crude oil, LNG, field gas or polymer plants, turbine, compressor, separator skids, tank farms, oil refinery feedstock lines, hydrocarbon processing, and more. While stainless steel ball valves are ideal for cooling water, petroleum refining, feed water, brewing, and desalination, high-pressure ball valves are ideal for underground, subsea, and cryogenic services.


Choose the Right Type of Control Valves for Your Application

The goal of ball valves and plug valves is to provide more control. They are called control valves because they ensure the best seals for a variety of industrial applications. To select the proper valve, it is critical to understand the differences and capabilities.


Despite being more expensive and heavier for larger-scale operations, plug valves rank higher in terms of tight sealing capabilities. It is true, however, that they are difficult to use. Ball valves are a better choice for larger applications requiring an easier operation. However, keep in mind that their sealing capabilities are not as good as plug valves. Additional technology and updated mechanisms may be required to improve the sealing ability of a ball valve for your large-scale application.


Our team of experts at DrillingParts can assist you in selecting the appropriate gas plug valves or ball valves for your application, including custom solutions based on your specific project requirements. We also have available gas regulators and measurement solutions, such as Romet rotary gas meters. Please do not hesitate to contact us if you have any special needs.