Ball Valve - How They Work

Standard floating ball valves consist of the housing, seats, ball and lever for ball rotation. They include valves with two, three and four ports which can be female or male threaded or a combination of those. Threaded valves are most common and come in many varieties: with approvals for specific media or applications, mini ball valves, angled ball valves, ISO-top ball valves, with an integrated strainer or a bleed point and the list goes on. They have a wide range of options and a large operating range for pressure and temperature.

For more information on a threaded connection, read our trunnion ball valve connection types article.

For more information on a flanged connection, read our electric actuator ball valve connection types article.To understand the working principle of a ball valve, it is important to know the 5 main 1 piece carbon steel ball valve parts and 2 different operation types. The 5 main components can be seen in the ball valve diagram in Figure 2. The valve stem (1) is connected to the ball (4) and is either manually operated or automatically operated (electrically or pneumatically). The ball is supported and sealed by the ball valve seat (5) and their are o-rings (2) around the valve stem. All are inside the valve housing (3). The ball has a bore through it, as seen in the sectional view in Figure 1. When the valve stem is turned a quarter-turn the bore is either open to the flow allowing media to flow through or closed to prevent media flow. The valve's circuit function, housing assembly, ball design, and operation types all impact the ball valve's operation are are discussed below.The handle is connected to the valve stem (Figure 2 number 1) and is capable of turning the valve from the open or closed position (90 degrees). If installed correctly, the valve will be open when the handle is parallel to pipe and closed when the handle is perpendicular to the pipe. Taking note of the handle direction is important to visually know if the valve is open or closed. There are additional 1 piece ball valve handle types, like lockable handles or ball valve handwheels. These operate as their names suggest. If you have a bigger ball valve or need additional torque to open or close the valve, a ball valve handle extension may be required. If your handle breaks, is miss-placed or you are converting an automatic ball valve to a manual one, you can buy ball valve handle replacements.

Approvals

For certain applications, approvals are desired or required. Drinking water and gas are the most common. Choosing a certified 2 piece floating ball valve, assures that the product meets important safety requirements.