Spindle seal

The spindle seal is a crucial component in valves, ensuring that the spindle (or shaft) that moves the valve’s closing element is guided through the valve body to the outside without the medium escaping. It enables the movement of the actuator (e.g., handwheel or motor) to be transmitted to the inside of the valve while ensuring a reliable seal between the inside of the valve and the environment.

Design and materials

The spindle feed-through usually consists of a cylindrical component that encloses the spindle. Seals or stuffing boxes are used to ensure a tight seal. These can be made of various materials, such as PTFE, elastomers, or special sealing rings, to prevent corrosion, abrasion, or leakage.

Function of the spindle seal

The main task of the spindle seal is to create a tight connection between the moving spindle and the fixed valve housing. While the spindle rotates or moves linearly, the seal remains intact to keep the medium in the valve and support pressure build-up. It prevents the medium from escaping from the valve and at the same time protects the spindle from external influences.

Areas of application

Spindle guides are found in all valve types where the spindle is guided through the housing to the outside, such as:

• Ball valves
• Shut-off valves
• Control valves

Summary

The stem seal plays an essential role in the sealing and movement of valves. It ensures that the stem movement is transmitted efficiently without allowing the medium to escape, thus ensuring safe and reliable valve operation.