Valve stem
The valve stem is a critical component that acts as a link between the drive mechanism (e.g., handwheel or actuator) and the valve’s closing element. Its task is to transmit the movement of the drive to the closing element in order to control the flow of the medium.
Valve spindle design
The spindle is usually a long, cylindrical rod made of high-strength materials such as stainless steel, carbon steel, or alloys to withstand mechanical forces and corrosive environments. Depending on the valve type, the spindle moves linearly or rotates:
- Linear movement: In shut-off valves or control valves, the spindle is moved up and down to open or close the closing element.
- Rotary movement: In rotary cone valves or ball valves, the spindle is rotated to turn the ball or cone and open or block the flow.
Materials and requirements for valve spindles
The valve spindle must withstand high mechanical loads and chemical influences. Therefore, the materials used for spindles are often very resistant:
- Stainless steel: Offers high corrosion resistance and strength and is used in many applications with aggressive media and high temperatures.
- Alloy steel: Offers additional strength and is often used in high-pressure and high-temperature applications.
Sealing and spindle feedthrough
To prevent the medium from escaping from the valve along the spindle, the spindle feedthrough is equipped with seals or stuffing boxes. These components must ensure a tight connection between the spindle and the valve body and minimize friction to enable smooth operation of the spindle.
Function and significance
The valve spindle transmits the mechanical force of the actuator to the closing element and plays a crucial role in the precise control of the valve. It must be manufactured with extreme precision to ensure the tightness of the valve and the accurate control of the medium.