The Guidelines For Gland Packing Installation

Gland Packing Installation for Valves

• Step: Use a specialized tool, such as a Gland Packing hook, to completely remove the old gland packing from the stuffing box.
• Cleaning: Thoroughly clean the stuffing box and valve stem. Inspect the stem for wear, scratches, or damage. If the stem is excessively worn, replace it immediately.
• Surface Standards: For optimal sealing, the valve stem surface roughness should be around 0.8 μm, while the stuffing box bore should have a maximum roughness of 3.2 μm.

• Measurements: Measure the valve stem diameter, stuffing box bore diameter, and depth.
• Calculate Gland Packing Size: Determine the cross-sectional size of the packing using the formula:
  Cross-sectional size = (Stuffing box bore diameter – Valve stem diameter) ÷ 2.

• Technique: Cut the gland packing into individual rings—do not spiral it into the stuffing box as a continuous coil.
• Tool: Use a spare valve stem (with the same diameter as the actual stem) as a mandrel for cutting.
• Process: Wind the gland packing tightly around the mandrel without overstretching it. After cutting, verify that each ring fits the stuffing box properly.

• One at a Time: Install one gland packing ring at a time, ensuring each is clean and free of debris.
• Fit: Press each ring firmly into place before adding the next. Ensure the ring is fully seated.
• Stagger Joints: Offset the seams of consecutive rings by at least 90° to prevent leakage paths.
• Compression: After installing the required number of rings, use the gland follower to press them into place.

• Compression: Once the final ring is installed, tighten the gland follower to apply 25% to 35% compression to the packing.
• Torque: Record the torque value applied to the gland nuts. Operate the valve through its full stroke (open and close) 5 times, stopping with the stem at its lowest position.
• Re-tighten: After each cycle, re-tighten the gland nuts to the recorded torque value to maintain consistent compression.

Gland Packing Installation for Pumps

• Step: Use a gland packing hook to remove all old packing, taking care not to scratch the shaft or sleeve.
• Thorough Removal: Remove all gland packing rings, including any lantern rings and the packing beneath them.
• Inspection: Clean the stuffing box and inspect the shaft and sleeve. Replace any components that are scratched or worn.

• Measurements: Measure the shaft diameter, stuffing box bore diameter, and depth.
• Calculate Gland Packing Size: Use the formula:
  Cross-sectional size = (Stuffing box bore diameter – Shaft diameter) ÷ 2.

• Technique: Cut the gland packing into individual rings—avoid spiraling it into the stuffing box.
• Tool: Use a mandrel (matching the shaft diameter) for cutting.
• Process: Wind the gland packing snugly around the mandrel without excessive tension. Check that each ring matches the stuffing box dimensions after cutting.

• One at a Time: Install one ring at a time, ensuring cleanliness and no contamination.
• Lubrication: Lightly lubricate the inner surface of each ring for easier installation.
• Fit: Close the ring’s joint and roll it into a circle from one end to the other.
• Stagger Joints: Offset the seams of consecutive rings by at least 90°.
• Secure: Use a tamping tool to seat each ring in place firmly.

• Placement: If a lantern ring is used, ensure it is positioned below the flush port.

• Initial Compression: After installing the final ring, press the gland follower onto the packing and hand-tighten the gland nuts.
• Caution: Avoid excessive gland pressure to prevent over-compressing the packing.
• Startup: Start the pump and gradually tighten the nuts until leakage is reduced to the minimum acceptable level.
• Even Tightening: Ensure all gland nuts are tightened uniformly to avoid overheating or burning the packing.

• Initial Leakage: Allow the gland packing to leak freely when the pump starts. After 1 hour of operation, gradually reduce the leakage.
• Adjustment: Tighten the gland nuts incrementally (e.g., one flat at a time) until the desired leakage rate is achieved.
• Temperature Check: Ensure the stuffing box remains cool during pump operation.