Figure 1: One-piece ball valve
A ball valve is a shut-off valve in piping systems, controlling the flow of liquids or gasses. Understanding the differences between 1, 2, and 3-piece ball valves is essential for selecting the right valve for any application. This article examines the design, performance, and specific applications of these ball valve configurations. This article compares 1, 2, and 3-piece ball valves in detail. Read our ball valve overview article for more details on the design and working of ball valves.
In short, the main difference between 1, 2, and 3-piece ball valves is their body design. A one-piece ball valve has only one body portion. Two-piece ball valves have two body components threaded together or bolted together. Three-piece valves, on the other hand, have three independent components.
Building a single-piece ball valve is simple as there is only one body part. The valve trim is attached to the seals through end connections made of the same material as the body. Also, the valve's port size will not be the same as the line size, resulting in a reduced bore design. There is very little or rather no leakage with this type of construction. A one-piece ball valve is irreparable, and it can only be replaced. Figure 1 shows a one-piece ball valve.
One-piece ball valves do not have uses in high-demand industries since they are difficult to repair or replace. In applications where a reduced flow is not a concern, one-piece valves can be employed. Foodservice machinery, liquid filling equipment, and motor fluid filling equipment use one-piece ball valves.
Two-piece valves have two independent components connecting them, either threaded or a bolt and flange assembly. The pieces have body and end connections. As two separate sections are connected, there is the possibility of leaking. As a result, the two-piece ball valve is unsuitable for high-pressure applications. Because of the connection, the valve can be disassembled for internal component repair.
A two-piece ball valve's structure allows it to be used in various applications. The valve can be used with any media because of the ease of maintenance. Food, manufacturing, and automotive industries are just a few of the industries that use two-piece ball valves.
Figure 2: 2-piece ball valve
A three-piece ball valve has one main valve body and two pipe connectors. The pipe connectors are welded or threaded to the pipes. Because of the three-piece structure, the valve body and trims can be removed without interfering with the pipe connections. After installing a 3-piece ball valve, the worn-out components like the ball, seat, or stem can be replaced independently and quickly. It is also more expensive than a two-piece ball valve due to its intricate structure. But, the valve can remain in service for its intended lifespan with low long-term maintenance cost.
The structure of a three-piece ball valve makes it suitable for high-pressure applications where the components experience a lot of wear and tear. The valve is ideal for high-cycle industries since the parts can be replaced and serviced without replacing the entire valve. Primarily, manufacturing industries mainly rely on three-piece ball valves to control liquid flow.
Figure 3: 3-piece ball valve made of stainless steel
Learn more about selecting the right ball valve for your application in our ball valve selection guide.
Any quick internet search for valves will show many different results: manual or automated, brass or stainless steel, flanged or NPT, one piece, two piece, or three piece, and more. With so many different types of valves available, how can you be sure you are purchasing the right type? While your application will help guide your proper valve selection, it is important to have some basic understanding of the different types of valves offered.
One-piece ball valves have a solid, cast body which reduces the risk for leakage. They are inexpensive and generally not repaired.
Two-piece ball valves are some of the most common ball valves used. As the name suggests, the two piece ball valve consists of two pieces, one piece that has one end connection and the body. The second piece fits into the first, holds the trim in place and includes the second end connection. Once installed these valves typically cannot be repaired unless they are removed from service.
Again, as the name suggests, three-piece ball valves consist of three pieces: two end caps and a body. The end caps are typically threaded or welded to the pipe and the main body section may be easily removed for cleaning or repair without removing the end caps. This can be a very valuable option because it prevents a line shutdown if maintenance is required.
By comparing the features of each valve with your application requirements, you will be able to make an informed decision on which will best suit your needs. Please visit our valves website to learn about our ball valve product line or start configuring today.