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What is a high-pressure ball valve?
A high-pressure ball valve is a ball valve that can operate at more than 500 psi without the valve body getting damaged. High-pressure ball valves use a ball with a hole at its center to open or close the fluid flow. The ball makes a quarter turn or 90o angle to either allow or block fluid flow. When the hole on the ball is in line with the fluid flow, the valve is open. The high-pressure ball valve is closed when the ball is pivoted at 90o using a handle or actuator. High-pressure ball valves are very strong enough to withstand high pressure and temperatures. Also, high-pressure ball valves are durable which makes them able to retain their high quality even when used for many cycles. High-pressure ball valves are made of metallic materials such as stainless steel and steel materials. High-pressure ball valves are connected using compression or threaded type connection or bolts and nuts.
Figure: High pressure ball valve.
Components of high-pressure ball valves
Body
The body in a high-pressure ball valve is the part which contains all internal components of the valve. The body is made of strong materials such as stainless steel, carbon steel among other strong metallic materials. Anti-static materials are also used to ensure valve durability and proper function.
Stem
The stem is the component of high-pressure ball valves that connects the actuator or the handwheel to the ball to enhance fluid flow control. The stem is also made of strong material to make it transmit the opening and closing torque as well as work in high pressure and high-temperature applications.
Seats
The seats are internal components in a high-pressure ball valve that are reinforced with seat rings to ensure a leakage-free valve. The seat could be metallic or made of other materials like an elastomer.
Ball
The ball is the component in a high-pressure ball valve made of strong material like steel depending on the valve application. The ball is responsible for blocking or allowing fluid flow in a high-pressure ball valve. The ball surface is perforated to enhance even pressure distribution. High-pressure ball valves can have reduced bore balls or full bore balls. Reduced bore balls are best in applications where fluid flow pressure has to be minimized by limiting flow. Full bore balls are used where unrestricted fluid flow is needed.
Actuator
High-pressure ball valves are turned on and off by use of manual or electric or pneumatic actuators. Manual actuators are operated by valve operators. Electric and pneumatic actuators are used in extremely high-pressure applications that can be automated.
Trim
Trim refers to replaceable or removable parts of high-pressure ball valves which get into contact with the fluid flow. Such components include stem, seating surfaces, ball, and seals.
Figure: Components of high pressure ball valve.
How does a high-pressure ball valve work?
To open a high-pressure ball valve, the actuator or handwheel turns 90o. As such, the actuator/handwheel which is connected to the stem makes the stem rotate. The stem is connected to the ball so that when the stem rotates the ball turns. The ball in the high-pressure ball valve rotates enough making the hollow side of the ball collinear with the pipeline thus fluid will flow unrestricted through the valve. To stop fluid flow, the actuator rotates again to make 90o turn. This rotation makes the ball rotate such that the hollow side of the ball becomes perpendicular to the pipeline. As such, fluid flow will be stopped as the fluid pressure will cause the seats and ball to form a firm seal.
Types of high-pressure ball valves
Top entry high-pressure ball valve
This is a high-pressure ball valve in which the ball is assembled from the top side. This type of high-pressure ball valve design makes it possible to do maintenance on the ball and seats without disconnecting the valve from the pipeline. The high-pressure top-entry ball valve can be cleaned while it is still connected to the main pipeline. In most cases, top-entry high-pressure ball valves are made using the casting method which necessitates a non-destructive test to check defects from the casting process. Top entry high-pressure ball valves have minimal connections which reduces the possibilities of leakage.
Figure: Top-entry high pressure ball valve.
Side entry high-pressure ball valve
The side-entry high-pressure ball valve is a ball valve in which the ball is assembled from its side part. In most cases, the valve body of the side entry high-pressure ball valve is in two or three parts. The parts of this side entry ball valve are connected using bolts and nuts. A strong material like steel is used to make the valve body of a side-entry high-pressure ball valve. Side-entry high-pressure ball valves are easy to assemble. The trim components of this high-pressure ball are properly aligned.
Figure: Side-entry high pressure ball valve.
Two-way high-pressure ball valve
This is a high-pressure ball valve that has two ports one for the inlet and the other one for the outlet. This type of high-pressure ball valve allows fluid to flow straight from the inlet port to the outlet port through the ball. This helps to reduce pressure drop as there is no change in direction of flow. A two-way high-pressure ball valve is suitable for on/off applications working on fluids and slurries.
Three-way high-pressure ball valve
A Three-way high-pressure ball valve is a valve with three ports. This high-pressure ball valve design uses a T or L formation. With this design, a high-pressure 3 way ball valve is capable of different fluid flow manipulations like mixing or diverting fluid flow. When the actuator or handle of this high-pressure ball valve is turned on, it turns the ball to align the bore on the ball with the inlet and outlet valve ports. The three-way high-pressure ball valve with L shape configuration allows fluid flow through 90o angle from one port to another port (fluid diversion). A Three-way high-pressure ball valve with a T-shape configuration allows fluid flow from one port to another (fluid diversion) and it also allows fluid flow from two ports to mix and then ejected to the pipeline.
Figure: Three-way high pressure ball valve.
Flanged end high-pressure ball valves
Flanged end high-pressure ball valves are one-piece or two-piece ball valves that have flanged ends with holes for bolts to connect the valve to the pipeline. This type of high-pressure ball valve can easily be installed or removed from the piping system easily. These valves are made of strong metallic materials that can help them stand the high pressure and high temperatures associated with the fluid flow as well as slurries.
Figure: Flanged end high-pressure ball valve.
Trunnion high-pressure ball valve
This is a high-pressure ball valve that has the ball supported by an additional shaft called a trunnion. The trunnion holds the valve ball in its position and reduces ball movement to its axis. The ball in this trunnion ball valve moves only if the stem or shaft turns. Trunnion high-pressure ball valves also have seats loaded with spring. The springs are activated by inlet fluid pressure towards the valve ball held by the trunnion which helps to create a tight seal. Trunnion high-pressure ball valves operate efficiently in wide levels of pressure. Trunnion high-pressure ball valves operate easier with a small actuator or lower operating torque.
Figure: Trunnion high-pressure ball valve.
Actuators used in high-pressure ball valves
Applications of high-pressure ball valve
Advantages of high-pressure ball valve
Disadvantages of high-pressure ball valve
Troubleshooting high-pressure ball valves
Seat leakage
Leakage through the body
Leakage through gland packing
Leakage through the stem
Handle or actuator not working
Summary
High-pressure ball valves are ball valves used in high-pressure applications above 500 psi. High-pressure ball valves have the ball with a bore where the media passes through. High-pressure ball valves operate by turning the ball through 90o which opens/closes the fluid flow through the valve. The fluid flows through the ball bore when the bore is collinear with the pipeline. A high-pressure ball valve is closed when the ball turns 90o such that the hole becomes perpendicular to the pipeline. High-pressure ball valves are strong valves made of strong metallic materials such as stainless steel, carbon steel, and cast iron among other materials. High-pressure ball valves are used in different applications such as mining, oil and gas industries, chemical industries, construction, fire protection, and steam power plants, marine and offshore applications among others. There are various types of high-pressure ball valves which include two-way high-pressure ball valves, three-way high-pressure ball valves, trunnion high-pressure ball valves, flanged end high-pressure ball valves, top entry high-pressure ball valves, and side entry high-pressure ball valves.