How To Install Pump Packing

Are you struggling with leaking pump seals? Installing new pump packing can help.

Pump packing is a cost-effective solution for sealing rotating shafts and preventing leaks. It’s a relatively simple process that can be done with a few tools and some know-how.

In this blog post, we’ll walk you through the steps to properly install pump packing and ensure your pump operates efficiently.

Packing Removal and Stuffing Box Inspection

Removing Old Packing

Begin by completely removing all old packing from the stuffing box, including the lantern ring if present.

Use appropriate removal tools such as packing hooks or extractors, taking care not to damage the shaft, sleeve, or stuffing box surfaces.

Ensure all packing debris is cleared to prevent contamination.

Cleaning and Inspection

Thoroughly clean the stuffing box using suitable solvents or cleaning agents.

Inspect the shaft or sleeve condition for signs of wear, scoring, or damage. If excessive wear is observed, consider replacing the shaft sleeve.

For split case pumps, check the bore diameter and gasket condition.

Preparation for New Packing

Before installing new packing, ensure all surfaces are clean and free from debris.

If a lantern ring is used, verify its position aligns with the flush port.

Check that the gland follower moves freely and the gland nuts are in good condition.

Cutting the Packing Rings

Using a Mandrel

Cutting packing rings requires precision to ensure proper sealing.

A mandrel with the same diameter as the pump shaft is essential for accurate cutting.

If no shaft wear is present, rings can be cut directly on the shaft outside the stuffing box.

Wrapping and Cutting Process

To cut packing rings, wrap the packing material firmly around the mandrel without excessive stretching.

Hold the packing tightly in place and make a clean cut through all layers.

This method ensures consistent ring sizes that match the shaft diameter.

Skive Cut vs. Butt Cut

Two primary cutting techniques are used: the 45° skive cut and the 90° butt cut.

The skive cut is preferred for individual rings, while the butt cut works well for cutting multiple rings simultaneously.

Both methods help create an effective seal when properly executed.

Avoiding Excessive Stretching

When cutting packing rings, it’s crucial to avoid stretching the material excessively.

Overstretching can compromise the integrity of the packing, leading to premature wear and reduced sealing effectiveness.

Maintain a firm hold without applying undue tension to the material.

Individual vs. Multiple Cuts

Packing rings can be cut individually or in multiples, depending on the specific application and packing type.

Individual cuts allow for more precise sizing, while cutting multiple rings at once can save time during installation.

Precision Packing Installation

Preparing and Lubricating Packing Rings

Each ring should be coated with a suitable lubricant, such as Pak-Lube®, Go-Jo, or liquid soap.

Avoid using anti-seize or metallic-based compounds on pump packing.

Lubrication helps reduce friction during installation and initial operation, promoting better sealing performance.

Installing and Seating Packing Rings

Install packing rings one at a time, firmly seating each against the bottom of the stuffing box.

Use appropriate tamping tools, such as a split bushing or custom-made tools, to ensure proper seating.

Never use screwdrivers or sharp objects, as they can damage the packing material.

Stagger the ring joints 90° apart in the stuffing box, following the 12, 3, 6, and 9 o’clock positions for optimal sealing.

Lantern Ring Positioning

Ensure the lantern ring aligns with the flush port to allow proper flow of flush water.

To verify alignment, insert a small object through the flush port and feel for the lantern ring.

Gland Follower Adjustment

After installing all packing rings, tighten the gland follower finger-tight.

During the break-in period, make gradual adjustments by tightening the gland nuts only 1/6 turn (one flat) at a time, allowing 5-10 minutes between adjustments.

This careful process ensures proper seating of the packing and helps achieve the desired leakage rate of 10-12 drops per minute per inch of shaft sleeve diameter.

Establishing the Flush System

Flush Pressure Requirements

The flush pressure must exceed the stuffing box pressure to prevent product intrusion.

A general rule is to maintain flush pressure at least 20 psi higher than the maximum stuffing box pressure.

Installation of Control Valves

Install a flow control valve on the flush supply line to regulate the incoming water flow.

On the exit side of the stuffing box, install a pressure gauge followed by a needle or globe valve. This setup allows for precise control of both flow rate and pressure.

Adjusting Flow and Temperature

Adjust the flow rate using the supply line valve until the flush water exiting the stuffing box is cool to the touch. This ensures adequate cooling and lubrication of the packing rings.

Fine-tune the pressure by throttling the exit valve while maintaining the desired flow rate.

Optimizing Flush Water Consumption

Balance the flow rate and pressure to minimize flush water consumption while ensuring effective sealing.

Start with a higher flow rate and gradually reduce it while monitoring leakage and temperature. Aim for a flow that provides sufficient cooling and sealing without excessive water usage.

Startup, Break-in and Adjustment

Initial Startup Procedure

Allow controlled leakage at startup for the first 30-60 minutes. This initial leakage is crucial for proper seating of the packing rings and helps prevent excessive heat buildup. During this period, monitor the stuffing box temperature and leakage rate closely.

Gradual Gland Adjustments

Make gradual gland adjustments in small 1/6 turn increments using the gland nuts. Wait several minutes between each adjustment to assess the impact on leakage and temperature. This careful approach prevents over-tightening, which can lead to premature packing failure and shaft wear.

Target Leakage Rate

Aim for a target leakage rate of 8-12 drops per minute per inch of shaft diameter. This rate ensures adequate lubrication and cooling of the packing while minimizing fluid loss. Monitor both the shaft ID leakage (necessary for proper operation) and bore OD leakage (unnecessary and should be minimized).

Temperature Monitoring

Continuously monitor the stuffing box temperature during the break-in period. If the packing is running hot, loosen the gland follower slightly and reassess. Proper temperature control is essential for maximizing packing life and preventing shaft damage.

Startup, Break-in and Adjustment

Initial Startup Procedure

Allow controlled leakage at startup for the first 30-60 minutes. This initial leakage helps prevent excessive heat buildup. During this period, monitor the stuffing box temperature and leakage rate closely.

Gradual Gland Adjustments

Make gradual gland adjustments in small 1/6 turn increments using the gland nuts. Wait several minutes between each adjustment to assess the impact on leakage and temperature.

This careful approach prevents over-tightening, which can lead to premature packing failure and shaft wear.

Target Leakage Rate

Aim for a target leakage rate of 8-12 drops per minute per inch of shaft diameter. This rate ensures adequate lubrication and cooling of the packing while minimizing fluid loss.

Monitor both the shaft ID leakage (necessary for proper operation) and bore OD leakage (unnecessary and should be minimized).

Temperature Monitoring

Continuously monitor the stuffing box temperature during the break-in period. If the packing is running hot, loosen the gland follower slightly and reassess.

FAQs

How often should pump packing be replaced?

Pump packing should typically be replaced annually. However, replacement frequency depends on operating conditions, packing material, and pump usage.

How can you determine when a pump needs new packing?

Signs that a pump needs new packing include:

• Excessive leakage from the stuffing box
• Increased temperature around the packing gland
• Visible wear or damage to the packing
• Inability to control leakage through gland adjustments
• Burnt or discolored packing material
• Frequent need for gland tightening

In Conclusion

Installing pump packing is a straightforward process that requires attention to detail and the right tools. Following the steps outlined in this guide will ensure a properly packed pump, extending its life and improving its efficiency.

For more information on pump maintenance, consult the manufacturer’s documentation.