Why Mechanical Seal Support Damage Occurs in Winter: Understanding the Problem and Your Potential Solutions

Seal support systems are essential for the operation of pumping and rotating equipment, as they are designed to support a specific seal and set of process conditions by supplying either a liquid or gas to lubricate or flush contaminants from the seal. When a mechanical seal support system is damaged, this can pose a significant threat to the pump itself. If a support system is damaged and the associated pump remains operational, a number of problems can arise that may lead to major pump repairs or rebuilds. This can include:

• Vibration problems
• Damaged bearings within the pump
• Damaged coupling between the shaft and motor
• Scoring or heat damage to the shaft

Mitigating these issues becomes especially challenging during winter months when repairing a pump in the field may not be possible until a storm passes. Proactively checking seal support systems and repairing or replacing any that are damaged prior to winter is ideal. Let’s take a look into probable mechanical seal support damage reasons and preventative measures that can be taken to avoid them.

Top Mechanical Seal Support Damage Reasons

Within petrochemical refineries and oil & gas operations, there are likely to be hundreds of pumps that rely on seal support systems for reliable operation. Regular checks of seal support systems are critical, especially prior to winter, and can prevent common reasons for mechanical seal support damage. Seal support systems may present with damage during winter, or otherwise, due to damaged or inoperable instrumentation, buildup on seal pot heat exchangers or cooling coils, or seal face corrosion.

Damaged or Inoperable Instrumentation

Proper instrumentation for seal support systems, such as gauges, sensors, and flowmeters, provide on-the-spot feedback regarding system performance and are critical for monitoring the state of seal support system efficacy. However, when such instrumentation is damaged or inoperable, seal support system problems and potential damage are likely to occur.

A number of problems may go unnoticed if functional and accurate instrumentation is not in place:

• Increased temperature is typically the first sign that a seal support system is not providing the necessary cooling or lubrication the seal requires and may ultimately lead to mechanical seal failure.
• Reduced fluid pressure may lead to process fluid migrating across seal faces, resulting in excess heat buildup due to friction. 

Preventative Measures: Implement block and bleed or isolation valves for instrumentation. This will allow for ease of repair, replacement, and calibration of seal support system instrumentation, preventing any downtime that would otherwise be required to remedy the issue.

Build-Up on Seal Pot Heat Exchangers or Cooling Coils

When plant water is used, mineral buildup, scale, or corrosion can form on seal pot heat exchangers or cooling coils associated with seal support systems. When buildup occurs, thermal conductivity decreases which, depending on the severity of buildup, may lead to increased flush fluid temperature and thus increased seal chamber temperature.

Preventative Measures: Buildup on seal pot heat exchangers and cooling coils is more or less inevitable over time. However, preventative measures and routine maintenance, including descaling coils, should be completed on a regular basis. Easily accessible seal pots and easily removable cooling coils and heat exchangers allow for this process to be quick and simple. Additionally, well-purified plant water can potentially reduce the buildup, allowing for longer lifetimes of cooling coils and heat exchangers.

Seal Face Pitting or Corrosion 

Corrosion is tricky, as it is often on the internal side of piping or seal pots and may go unnoticed for a significant amount of time. Over time, corrosion in seal pots or process piping can migrate to seal faces, causing significant damage to the seal that may lead to seal failure if not caught in time.

Preventative Measures: Seal face corrosion can be reduced by implementing filters and strainers in appropriate locations, preventing particulates from entering the seal chamber. The use of bypass loops can allow for filters and strainers to be replaced or cleaned while still supplying continuous flush fluid. Stainless steel seal pots and tubing can offer higher resistance to corrosion than other materials, such as carbon steel.

Seek Local Seal Support Experts

As maintenance, repairs, and replacements of pumps and their seal support systems can be difficult during winter in cold climates, the best course of action is to place focus on preventative actions. Due to the dependent nature of mechanical seals on their support systems, it is critical to keep a watchful eye on support systems to prevent damage and catch it early before it leads to facility downtime. Utilizing seal support systems that are inherently designed for ease of maintenance allows for the ability to maintain critical seal equipment while maximizing uptime.

Edmonton Valve & Fitting’s Field Advisors can perform an onsite analysis of your seal support system to identify opportunities to improve safety and efficiency. The Field Advisory team is able to capture site data and provide a baseline of information that can be used to trend comparisons for future preventative maintenance programs.