The top ball valve  is coupled to a handle, gear operator or actuator that rotates the shaft of the metal disc attached to the interior of the valve by 90°. When the disc is rotated in the direction of flow, the valve is fully open, allowing material to move across the disc and move down the pipe. Conversely, turning the disc so that it is seated on the flow path will block the flow.
Ball Valves are also connected to the handle or actuator of the rotating valve shaft, but unlike top ball valves, they contain a spherical ball with a hole drilled in one direction to block or release flow. Rotating one half of the drilled ball toward the material releases the flow while blocking the solid side of the ball toward the material.

top ball valve: Applications and Advantages
top ball valves are commonly used to regulate the flow of gases, liquids or slurries. Because they can be designed with reference to specific pressure requirements and usage patterns, they are very versatile. Some of the more common applications include: water, air, gas cooling; fire protection; food and beverage production; chemical processing; pharmaceutical industry; slurry services; throttling; vacuum services.

top ball valves offer many advantages over other flow management solutions, including:
Speed
The top ball valve opens quickly compared to a multi-turn valve. The ability to remotely control them also saves time because the user does not need to go to each valve position.
Affordability
top ball valves are less expensive than most other types of valves due to their low material density.
Size
Because the top ball valve assembly is smaller than other valves, it is ideal for applications where space requirements are small.
Damper
top ball valves are ideal for applications that require continuous throttling of liquids, gases or slurries.
Low maintenance
top ball valves tend to require little maintenance and most have a long service life.
Easy installation
top ball valves are generally easier to install than other valves.
Leakproof
The combination of automated speed and standard tight sealing of the top ball valve virtually eliminates waste or leakage.

Ball valves: Applications and Benefits
Ball valves are used in liquid and gas applications where tight sealing is required. Like top ball valves, they can be used for a variety of purposes. Ball valves are becoming more popular in many industries because of their better control. Their applications include: chemical treatment; life sciences; high pressure; high temperature; food and beverage production; measurement and control; utilities; water cooling; drains and vents.

Ball valves have many advantages over manually operated ball or top ball valves, including:
Speed
The ball valve can be opened and closed faster than a multi-turn valve. The ability to remotely control them also saves time because the user does not need to go to each valve position.
Multiport
Applications that require superior control can benefit from the control provided by the multi-port automatic ball valve.
Long lasting
Ball valves are designed to withstand the pressures of strong industrial applications. To extend product life, many valves also allow parts to be replaced during maintenance.
Simple
Automatic control of the ball valve at a single control point simplifies operation and simplifies existing processes.
Leakproof
The combination of automated speed and standard tight seals for ball valves virtually eliminates waste or leakage.
The whole process
In the absence of a flow barrier, the ball valve provides a higher flow rate than the top ball valve.