What is the difference between 1-, 2- and 3-part ball valves?

 What is the difference between 1-, 2- and 3-part ball valves?

 

The housing of a ball valve can be constructed in different ways. Common variants are the one-piece, two-piece and three-piece body. The operation of the ball valve is the same in each embodiment, the differences are in the possibilities for maintenance or repair.

One piece ball valves

This is a simple and inexpensive implementation. One-piece means that the body consists of one piece. Due to their construction, these valves generally have a reduced port. Repair of these valves is usually not possible. The disadvantage of this type is that in the event of a defect you have to remove the entire valve from the pipe. This can be tricky, if you are unlucky you also need to disassemble or replace part of the line. An advantage of this type of valve compared to the two- or three-piece variant is the lack of gaskets between the parts of the body. This will prevent any leakage between the parts.

This type of ball valve is used for simple applications.

 

Two-piece ball valves

In this type, the housing of the ball valve consists of two unequal parts. The largest part contains the handle, ball, seats and gaskets. In the cheaper models, these two parts are screwed together. In the slightly heavier embodiments, the two parts are coupled to each other with bolts. For maintenance or cleaning, you must remove this variant from the pipe. Then you can take the two parts apart and inspect the interior. Another disadvantage is that leakage can occur along the gasket between the two parts. Two-piece ball valves are available with a reduced or full passage.

 

Three piece ball valves

The great advantage of three-part ball valves is that you can remove the interior - with lever, ball, seats and gaskets - without removing the complete crane from the pipe. This way you can inspect the inside of a ball valve without too much key work. This can be a great advantage in many applications. The three parts are interconnected by bolts or tie rods. Three-part ball valves are often modular. This makes it possible to have two different connections on a valve. For example, on the one hand a flange connection and on the other hand a pipe thread. A disadvantage of this type is that seals are arranged between the three parts which can possibly cause leakage.