The difference between ball valve types is how the pieces of the valve are assembled and this affects the ways for maintenance or repair. The operation of the valves is the same in each housing type. The assembly of the valve housing can be divided into a few commonly used designs detailed out below.
Top Entry Ball Valve
Top Entry Ball Valves are valves that assembled their ball from the top side part. A top entry body allows access to the ball and seats for maintenance without the need to remove the valve and is preferred for larger sizes. It is not required to be removed the valve from the pipe system. Usually, top entry ball valves are made from casting metal. Since it is made from casting it will need some additional NDE tests to make sure that there is no defect from the casting process. The advantage of the top entry ball valves is their construction that allows minimal thread connection so that it will also minimize possible leak paths.
Side Entry Ball Valves
Side Entry Ball Valves are valves that assembled their ball from the side part. It is usually assembled in two pieces or three pieces of body. Each part of the body is assembled by a bolt stud just like joining a two-piece of flanges. Usually, side entry ball valves are made from forge metal. Each piece of the body is forged and then assembled together. This construction will minimize a defect caused by a casting valve. Side entry ball valves are also easy to assemble and the trim component is also easy to align. Another advantage of the side entry type is its fast delivery time from almost all vendors rather than a casting product that still needs some additional test.