Best Practices for Control Valve Packing Installation

During the installation process of control valves, the correct installation of packing is key to ensuring the valve's performance and long-term stable operation. The quality and installation method of the packing directly affect the sealing effect and operational performance of the control valve. This article will provide a detailed introduction to the inspection points before installing the control valve packing and the matters that need special attention during the installation process to help ensure the effective sealing of the packing and the reliable operation of the valve.

Inspection Before Packing Installation

Before installing the control valve packing, a comprehensive inspection of the relevant components must be conducted to ensure that the packing can be installed correctly and function as expected.

1. The packing box, pressure sleeve, and its accessories should be kept clean, without any damage, corrosion, or other defects. Ensure that these components are in good working condition before installation.
2. Check the alignment of the valve stem, gland follower, pressure sleeve, and packing box to ensure they are on the same axis, which is crucial for the even compression of the packing.
3. Inspect the roughness, cylindricity, and straightness of the valve stem to ensure the surface of the valve stem is smooth, without scratches, peeling, corrosion, or cracks. These defects may lead to poor packing sealing.
4. Conduct a gap inspection to ensure that the gaps between the valve stem and the steam seal, pressure sleeve, and packing box hole meet the usage requirements to avoid poor sealing or leakage.
5. Check the material, specifications, and model of the packing to confirm that they meet the process requirements. The packaging of the packing should be neat and tidy to avoid introducing impurities during the installation process.
6. For woven packing, check whether there are any loose defects in the weaving process to ensure the rise angle is consistent (30° or 45°). Moulded packing should be free of scratches, burrs, or cracks, and its size and precision should meet the requirements.

Points to Note During Packing Installation

When actually installing the control valve packing, pay special attention to the following aspects to ensure the correct installation of the packing and the normal operation of the valve.

1. Packing Preparation

For control valves that have been stored for a long time, the packing should be soaked in oil before use to maintain its elasticity and sealing performance, preventing it from becoming hard or ineffective.
When installing woven packing, it should be loaded into the packing box one by one. Ensure that the gap between each ring is staggered by 90° or 120°, avoiding filling the entire packing at once, which can lead to uneven sealing or packing deformation.
During the installation process, the valve stem should be rotated every 12 turns to check the contact between the valve stem and the packing to prevent the packing from jamming or affecting the valve's on-off operation.

2. Selection and Compaction of Packing

When selecting packing, avoid using narrow-width packing. If there is no suitable width, packing that is 1-2mm larger than the packing box can be used as a substitute, but avoid flattening the packing with a hammer. It is recommended to use a flat plate or roller to compact evenly.
After the packing box is basically filled, the packing is tightened with the gland follower. The bolts should be tightened symmetrically to ensure even force to prevent packing deformation or poor sealing.

3. Sealing and Inspection

Regularly check the gaps between the valve stem and the steam seal, pressure sleeve, and packing during the installation process to ensure that the sealing sleeve does not press the packing unevenly. Avoid the sealing sleeve contacting the valve stem and causing friction, which can lead to the packing becoming flat or leaking.

When installing moulded packing, it should be slowly inserted from the upper end of the valve stem, and the cut should not be opened, avoiding deformation of the packing during the installation process.

Be careful to prevent the inner ring of the packing from being scratched by the threads of the valve stem during the installation process, which may affect the sealing performance of the packing and the normal operation of the valve.

4. Testing and Adjustment

After the packing is installed, a detailed test should be conducted to check whether the packing is too tight or affects the on-off operation of the valve. Ensure that the operation of the valve is flexible and the sealing effect is good.

By carefully inspecting and correctly installing the control valve packing, leakage problems caused by poor sealing can be effectively avoided, ensuring the stable performance and extended service life of the valve. Following these guidelines ensures that every aspect of the packing is precisely handled, which is key to ensuring the normal operation of the system and improving the reliability of the equipment.