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1. Body
The body of a ball valve is the main outer shell that holds all the internal parts in place. It provides the structural strength to withstand the pressure of the fluid flowing through the pipeline. Ball valve bodies are usually made from durable metals such as stainless steel, brass, carbon steel, or sometimes plastic materials for lower pressure applications. The body also contains the ports for connecting to the pipeline, which can be threaded, flanged, or welded depending on the valve design.
2. Ball
The ball is the key component of the valve that controls flow. It is a hollow, perforated sphere inside the valve body. When the valve is in the open position, the hole in the ball aligns with the pipeline, allowing fluid to flow through freely. When the valve is closed, the ball is rotated 90 degrees so that the solid part blocks the flow. The ball is precision-machined for a smooth, tight seal and is often coated or made of materials like stainless steel or chrome-plated steel to resist corrosion and wear.
3. Seats
The seats are the sealing elements that surround the ball on either side. Usually made from soft, resilient materials like PTFE (Teflon), nylon, or other polymers, the seats ensure a tight seal between the ball and the valve body. This prevents leakage when the valve is closed. The seats must be durable enough to maintain their sealing properties under various temperatures, pressures, and fluid types. In some designs, the seats also help to hold the ball in position and cushion it during operation.
4. Stem
The stem is a shaft that connects the ball to the handle or actuator on the outside of the valve. When you turn the handle, the stem rotates the ball inside the valve. The stem passes through a sealed packing gland to prevent leaks along its length. The connection between the stem and ball is critical — it often uses a key, pin, or other locking mechanism to ensure the ball turns precisely with the stem.
5. Handle or Actuator
The handle is the manual control used to open or close the valve. It is usually a lever attached to the stem that allows quick 90-degree rotation of the ball. In industrial or automated systems, instead of a manual handle, electric, pneumatic, or hydraulic actuators are used to operate the valve remotely or automatically. The handle often includes a locking mechanism to prevent accidental operation.
6. Packing
Packing is the sealing material packed around the stem inside the valve body. Its job is to prevent any fluid from leaking out where the stem exits the valve. Common packing materials include PTFE, graphite, or other elastomers. Over time, packing can wear or degrade, so it may need to be adjusted or replaced to maintain a good seal.
7. Gland Nut (Packing Nut)
The gland nut is a component used to compress the packing material around the stem. By tightening the gland nut, the packing is squeezed to create a tight seal, preventing leaks. This is often adjustable to compensate for wear in the packing over the valve’s lifetime.
8. End Connections
End connections are the interfaces where the valve connects to the pipeline system. Common types include threaded ends (screwed onto pipe threads), flanged ends (bolted to flanges on pipes), and welded ends (permanently welded to pipe). The choice of end connection depends on the application, pressure rating, and ease of maintenance.
Summary
Each part of the ball valve plays a vital role in its overall function:
The body provides strength and houses the components.
The ball controls the fluid flow.
The seats ensure a tight seal to prevent leakage.
The stem transfers motion from the handle to the ball.
The handle or actuator enables operation of the valve.
The packing and gland nut prevent leaks around the stem.
The end connections link the valve into the pipeline.
Together, these Ball Valve Components create a reliable, easy-to-operate valve widely used in many industries for fluid control.
