Ball valves are well-known for their dependable, airtight flow shut-off and ease of use. Ball valves are smaller, lighter, and require less operating force than gate or globe valves. They come in a variety of designs and materials that provide flexibility, durability, and ease-of-use.
Ball valves are popular in piping systems used in a variety of industries, including:
Circuits that use pneumatics
Liquid filling processing
And there are many more!
Although they come in a variety of styles, all ball valves are classified by the port (or bore) size — the size of the opening in the ball through which the media flows. Continue reading to find out when each port size is preferable.
Full Port vs. Standard Port
Ball valve ports are available in standard and full sizes. The distinction is easily summarized:
The valve port has the same diameter as the pipe.
Standard port: The valve port is smaller than the diameter of the pipe. The exact port size varies, but it is typically one pipe size smaller than the valve in question.
As always, there are advantages, disadvantages, and appropriate applications for each.
Ball Valves with Full Ports (Full Bores)
When fully open, the straight flow path of a full port ball valve provides little to no resistance to the flow of liquid or gas, resulting in very little pressure drop.
This ensures that the valve does not reduce flow rate and reduces the possibility of cavitation, which is the formation of air bubbles as a result of a drop in liquid pressure. Over time, frequent or intense cavitation can erode or damage a piping system.
Having said that, when considering the entire application piping system, it is uncommon for the ball valve to be the flow rate bottleneck. We’ll go over this in greater detail later.
Ball Valves for Standard Ports
Because standard port ball valves have an opening that is typically one size smaller than the pipe diameter, even when fully open, they cause a greater pressure drop. This is due to the fact that the media is slightly constricted as it passes through the valve, increasing the pressure and potentially causing cavitation in applications where the smaller port size may cause a rapid pressure drop.
Standard port ball valves are typically more cost effective than full port designs for the same pipe size because they have smaller bodies that correspond to a narrower port. When compared to full port ball valves, they are available in the same or lower pressure ratings.
Is it possible to categorize other valve types based on port size?
Other types of valves’ port sizes rarely vary; gate and globe valves are almost always full port by design. This is due to their respective functions: Gate valves are simple open-and-close valves with a flat "gate" or disc across the port, whereas globe valves can throttle media flow while forcing it to take a different path through the valve. Different port sizes aren’t very useful in these types of valves.
Non-full port gate and globe valves do exist on occasion, particularly in the oil and gas industries, but they are uncommon.
When Should You Use Standard Port Ball Valves?
Standard port ball valves are ideal for the vast majority of ball valve applications. They are relatively small, allowing them to perform their function while taking up less space and costing less. If you need a ball valve with a quick on/off function, simple operation, durability, and a guaranteed leak-tight seal, any style — full port or standard port — will suffice.
Standard port ball valves are recommended as long as a moderate pressure drop and slight flow turbulence are acceptable in your system.
In fact, changes in flow rate are common in most piping systems; the length of pipe sections, bends in the system, or system conditions will all affect the flow rate to the point where a standard port valve is not the most influential factor. The difference between a full port and standard port ball valve will have no effect on the overall flow rate of the piping system in the vast majority of applications.
When Should You Use Full Port Ball Valves?
Full port ball valves perform the same functions as standard ports, but with the added benefit of lowering pressure drop. This is especially important in applications where maintaining flow rate is critical and the piping through which the media will travel is relatively short with few changes in direction.
Full port ball valves are recommended for systems with both solids and liquids flowing through the valves because they provide the least resistance to flow. The open design reduces the possibility of build-up inside and around the valve connection, which can degrade the valve’s overall performance over time.
If you have any questions about which port design is best for your application, please contact the lucky6s Valve team. We are always willing to assist.