Mechanical seals are necessary in many industrial applications to contain fluids and stop leaks in equipment, including agitators, pumps, and turbines. They can save operational downtime and improve safety and performance. However, correctly mounting and aligning them is essential to boost a machine’s reliability and lifespan. This article covers the significance of proper seal installation, the best practices to follow, and common mistakes to avoid.
Why Precise Alignment Is Critical
Seals act as barriers between stationary and rotating machine parts. They generally have stationary and revolving rings and secondary sealing features, such as wedges or O-rings. They work under different pressures, temperatures, and vibration levels, which can easily cause machine parts to move. By ensuring precise alignment, you can avoid problems like:
- Accelerated Wear: Misalignment leads to uneven load distribution on seal faces, concentrating stress on some areas. This imbalance results in uneven wear and speeds up the seals’ deterioration, increasing the risk of leaks.
- Heat Generation: Improper positioning causes excessive friction, raising temperatures to levels that can degrade the seal and lubricant. The seal face’s material can harden, crack, or lose elasticity, diminishing its sealing ability. Moreover, the lubricant can dissolve and become ineffective, further accelerating degradation.
- Premature Failure: The cumulative effect of early wear and excessive heat drastically shortens the service life of seals and results in premature seal failure. The issue can also cause potential damage to other machines, unplanned operational downtime, and costly repairs or replacements.
Proper Installation Practices
Industrial seals are designed differently for various applications and operating conditions. Understanding the nuances of each seal type is necessary to ensure they’re set in equipment correctly.
- Pusher Seals: Often used in general-purpose applications, pusher seals require careful attention to the positioning of the sleeve, gland packing, spring assembly, and pusher. The sleeve must be well-lubricated and sized precisely according to the shaft. Meanwhile, the gland packing must be installed in stages, with each ring staggered and compressed evenly to block fluid. The spring must be seated correctly, and the pusher should be able to move freely within its housing.
- Non-Pusher Seals: Typically used in demanding applications, non-pusher seals require precise alignment of the stationary and rotating faces. Gaskets and O-rings must also be appropriately placed and free of debris. Using specialized alignment tools is recommended to achieve accuracy within manufacturer-specified tolerances.
- Cartridge Seals: Although pre-assembled to simplify installation, cartridge seals still need to be handled with care. Inspect the seal for any damage and check if the shaft and housing are clean and free from scratches or burrs. The shaft should also have the correct dimensions. To mount the seal, carefully slide it onto the shaft and align it with the housing. Secure the bolts to the manufacturer’s specifications using a torque wrench.
- Component Seals: Unlike the other types, component seals require individual installation, from faces to springs. Keep the seal faces clean throughout the process and lubricate them sufficiently. Install and orient the component according to the manufacturer’s specifications.
Common Mistakes to Avoid
Installing and aligning mechanical seals is a meticulous process that requires keen attention to detail and careful handling. However, even experienced technicians can commit errors that compromise seal performance. Here are some critical pitfalls to avoid:
- Improper Lubrication: Applying inadequate or the wrong lubricant between seal faces can increase friction, generate excessive heat, and cause the seal to deteriorate prematurely. So, use the correct lubricant type and quantity specified by the seal manufacturer.
- Over-Tightening Bolts: While seals must be mounted securely, be careful not to tighten the bolts too much. Exerting excessive force can distort seal faces, crush gaskets, and create stress points that weaken the seal assembly. These issues can eventually lead to uneven load distribution and seal failure.
- Contamination During Installation: Dirt, debris, metal shavings, and other foreign bits can damage seal faces and hinder proper operation. Even microscopic particles can scratch them, creating leakage paths and accelerating wear. To prevent that, ensure your work area and the components are clean before installation. Use lint-free cloths and appropriate cleaning solutions to clear the components and surrounding environment of contaminants.
Maximize Seal Life With Proper Installation
Safeguarding your equipment and ensuring smooth operations begins with proper installation. It requires understanding the value of precise alignment and adhering to the best practices above. By remembering these tips, you can ease the burden of downtime and maintenance and focus on other critical aspects of your operations.
Keep seal failures from interfering with your operations. Partner with trusted seal engineers today for more insights on enhancing equipment efficiency and longevity.
