Mechanical Seal Support Failure Analysis: A Guide for SAGD Operations

Mechanical seal failures are the most common cause of pump downtime and failure, so mechanical seals and seal support systems must be very carefully designed with components and options selected according to the specific application. However, even high-quality seal support systems can fail unexpectedly for a variety of reasons. When this happens, it’s critical to conduct mechanical seal support failure analysis quickly and accurately, because every minute of downtime results in lost production.

Identifying the failure mode and root cause of a mechanical seal failure allows you to not only correct the immediate problem but prevent it from happening in the future. Thorough mechanical seal support failure analysis can help you understand the conditions under which the seal failed. 

In this article, we’ll look at the three most common types of seal support failures—leaks, overheating, and seal failure—what can cause them, and how to prevent them with proactive measures.

Leaks

Mechanical seals minimize leakage around rotating equipment by creating a “seal” between two very flat surfaces—one stationary and one rotating. These mechanical seal faces inevitably produce some leakage, but the leakage normally evaporates immediately and isn’t a problem. When leaks become noticeable, it’s time to perform mechanical seal support failure analysis to find out why.

When troubleshooting mechanical seal leaks, make note of any unusual noises, damage, or other symptoms accompanying the leak. Use the table below as a starting point to help you identify the cause of the leak.

Overheating

Overheating indicates either friction between rotating components or excessive fluid temperatures. There are two main reasons mechanical seals overheat: inadequate cooling and excessive friction. Refer to the table below to help diagnose the problem.

As you can see, there is a lot of overlap between the causes of leaks and overheating. Many mechanical seal failure modes can be traced back to the same underlying causes, so be sure to check for leaks as well and use the leak troubleshooting table to investigate.

Excessive heat can eventually lead to heat checking. Mechanical seal heat checking can be identified by fine radial cracks in the seal face caused by excessive stress from the mechanical load and thermal expansion. These cracks may be barely visible to the naked eye, so heat checking can go unnoticed until failure occurs and it’s too late to save the seal. The risk of heat checking increases with high temperatures and high-viscosity fluids like those used in SAGD. It is more common in brittle materials like tungsten carbide.

Seal Failure

The same underlying issues that cause leaks and overheating can eventually lead to complete seal failure. A mechanical seal failure likely began as a leak or overheated condition that went unaddressed. The same troubleshooting procedures for leaks and overheating apply, but once the seal has failed, correcting the problem becomes much more difficult. Therefore, it’s important to be proactive and check for problems like leaks and overheating before they cause major problems.

Get Help with Mechanical Seal Support Failure Analysis from Local Experts

Do you still need help with mechanical seal support failure analysis, or want to learn more about how to be proactive in preventing failures? Field Advisors at Edmonton Valve & Fitting can perform an onsite or remote evaluation to determine the cause of failure and make recommendations on upgrades, component materials, tubing diameters, and instrumentation to help deter mechanical seal failures.