If you’re an oil or gas engineer, you know that ball valves are very essential components of piping
ball valve with pneumatic actuator
If you’re an oil or gas engineer, you know that ball valves are very essential components of piping systems. They are used for various purposes throughout the oil and gas industry. For upstream applications, they control the flow of oil. For the midstream, they protect equipment by controlling the flow of gas and oil. For the downstream, they are used for refining crude oil.
Because of their prevalence in the industry, it’s important for every engineer to be familiar with the various kinds of valves, or at least the most common ones.
American Ball Valve Components
The major components of a ball valve are the body, the ball itself, the steam, and the seats.
The ball valve may be soft-seated or metal-seated. It can be multidirectional, bidirectional, or unidirectional—this depends on how many valve ports and seats there are. This is the same for multiport plug valves.
American Ball Valve Applications and Advantages
Listed below are some different kinds of American ball valve
1. Three-Way Ball Valve
Depending on the situation, the ports of a three-way ball valve can be set to one of three ways:
One inlet, two distribute;
One inlet, one outlet, and one diverted flow; or
Straight pass (no inlet).
There are three different patterns available in an American ball valve: full port type, reduced port type, and Venturi port type.
The full port type has an internal diameter that’s equal to the internal diameter of the pipe. This allows for pigging. In reduced and Venturi port types, the port is usually a pipe size smaller than the size of the line.
The spherical ball inside the valve can be free-floating or fixed—these are referred to floating types and fixed types, respectively. A fixed type valve is sometimes called a mounted ball valve.
2. Floating Ball Valve
In a floating ball valve, the ball is held in place by two elastomeric seats. Between these seats, the ball is able to “float” inside the valve’s body.
The valve stem is connected to a slot in the top of the ball. This allows the ball to rotate one-quarter turn, or 90 degrees.
The valve shaft allows for a limited amount of lateral movement for the ball, which is generated from upstream pressure against the ball. This lateral movement, though small, drops a load upon the ball great enough to press the ball against the downstream seat. This improves tightness to avoid leaks.
This kind of ball valve is capable of bidirectional shutoff. However, a floating ball valve is hard to operate when the upstream pressure is very high. To combat this problem, the mounted ball valve is used instead.
3. Mounted Ball Valve
The mounted ball valve offers a solution to the problem created by excessive pressure placed on a floating ball valve.
In a mounted American ball valve, a short shaft, called a trunnion, is set in the body. In this design, the ball and steam work together as a single unit. Two floating or spring-loaded seats support the ball.
The mounted ball valve design requires a lower operating torque. This, in turn, reduces the size of the actuator—as well as the valve’s overall cost. This difference in cost is an important factor as valve size and pressure class increase.
4. Split-Body Ball Valve
In a split-body ball valve, the valve’s body is divided into halves or thirds. The ball, stem, seat rings, and other internal mechanisms are held together inside the body with bolting.
There are more than 3,000 facilities in the Outer Continental Shelf (OCS) involved in collecting and producing oil and gas.