You will notice our website categorizes our ball valves into 1, 2 and 3 piece designs ... which is best for your application?
This is why there are factory trained sales engineers waiting for you to contact them, because we can review your application requirements and offer a few alternatives to consider without having to delve into intricacies of designs.
The 1 piece ball valve design tends to be the least expensive style having a standard (reduced) port and a solid 1 piece cast or molded body. Thus the advantages are reduced leakage paths and initial cost. Disadvantages include inability or difficulty with repairs (having to remove the entire valve from the pipeline unless its a Hayward valve with true-union connections). Although we do offer Fire Safe and Control Valve designs having a 1 piece body, there are more design and testing standards associated with 2 piece and 3 piece valve designs. If you do not have specific design, test and registration requirements, then selecting a 1 piece design compatible with your flow rate, pressure and temperature is the way to go.
The complexity of 2 piece ball valves enables satisfying many different industry design, testing and registration standards which are a requirement for some applications. Examples include ball valves designed in compliance with NACE MR-0175, ball valves tested in accordance with API 607 Fire Testing, and CE Certification.
The two piece ball valve design only has 1 body joint, thus technically an additional leakage path when compared to a 1 piece design, although this joint can be welded. The 2 piece design has a larger variety of connection types and sizes compared to 1 piece designs and its likely the most common industrial ball valve design; especially for flanged connections.
3 piece ball valves are the most complex because they have the most parts, which are necessary for the additional advantages this design offers, such as the ability to repair the valve without disturbing the pipeline connections. So you can imagine, for example, how important this feature is if you have threaded or welded connections. With 3 piece ball valves we can also offer a variety of end connections, for example the MULTI-CHOICE series enables you to combine different inlet and outlet connections, so the valve doubles as an adapter and potentially reducing the number of fittings (leak paths) otherwise required; this is an advantage of a 3 piece vs. 2 piece ball valve.
Special application valves, such those used for extreme temperatures (cryogenic applications), sanitary and piggable service all utilize the three piece design to ensure compatibility with the requirements of those special service conditions.
In summary, non-demanding light duty applications are good candidates for less expensive 1 piece ball valve designs whereas 2 and 3 piece ball valve designs are used for more demanding applications, whether that be extreme conditions or specialized design, test and certification criteria.