Like most refinery rotating equipment engineers, you have hundreds of different pumps to take care of. While some of the refinery's rotating equipment is in better shape than others, a mechanical seal failure somewhere along the line is inevitable—especially in some of the older California Bay area petrochem plants. You can usually take care of these problems quickly. But, when a mechanical seal is failing repeatedly, it is time to look at the other subsystems.

If you have a seal with known alignment problems, problems with insufficient cooling, or recurrent seal plugging, a root cause analysis should include taking a closer look at the seal support system.  An obsolete or insufficient seal support system can result in a variety of mechanical seal repair problems: leaks, seal face damage, or excessive process fluid leaking into the buffer fluid. 

You don’t need those problems on top of everything you are already taking care of. So, it’s best to develop a preventative maintenance plan that includes identifying “bad actor” mechanical seals and determining whether they need a seal support system upgrade or replacement. 

Frequent Mechanical Seal Repairs? Here’s What to Check

You already have maintenance records in hand and know which pumps to prioritize because of frequent mechanical seal repairs. Then, it’s time to start troubleshooting the seal support systems that are not functioning optimally. The process of checking the seal support system for brewing trouble may be familiar—it’s very similar to specifying a new system. But, even if you’ve never done that before, you won’t feel overwhelmed here. 

Let’s get started, one step at a time. 

Step 1: Examine the process conditions and fluid. 

Has anything changed, even if “just a little?” An insufficient seal system may not keep new contaminants out of the seal or the process fluid may no longer have good enough lubricity. You may need a new barrier/ buffer fluid. Or, if you can’t use the process fluid anymore, especially on a dual seal, it might be time for a new seal support system.

Step 2: Re-check for fugitive emissions. 

Many problems first show up as small seal system leaks. Small leaks only get bigger and will eventually become reportable. You’ll need to first fix the mechanical seal then go back and look at why the damage occurred in the first place. You might find that an upgrade or replacement needs to be added to the budget. 

Step 3: Take a good look at the seal support system instrumentation. 

Can you measure flow, pressure, or fluid temperatures? Should any of this data be recorded automatically? Too often excessive heat build-up could be seen with seal system instrumentation but isn’t noticed until there is a catastrophic failure.

It’s not uncommon that the instrumentation broke, operators stopped looking at it for early warning signs, and nobody got around to fixing it. If that’s the case, the time is now for resolving the problem by getting new instrumentation. 

Step 4: If you can measure seal fluid conditions, are they appropriate for the service? 

If not, you may not have proper lubrication or heat removal. The data can be right there in front of you showing a pump seal running too hot, but if no one checks… 

Yes, that means you need to upgrade the seal system to get proper heat removal restored. 

Step 5: If there is a seal fluid cooler, can you verify inlet and outlet temperatures? 

Small equipment like the cooling coils or smaller heat exchangers are often neglected. Does the cooler need to be cleaned or replaced? Aged and failing coolers are a simple fix that can avoid a much more expensive seal replacement if they are left unattended until failure. 

Step 6: Are you using the best barrier or buffer fluid? 

Too often water is used because it was cheap and readily available but it is only marginally acceptable. Seal replacements are often more frequent than they have to be, resulting in higher lifecycle costs. The variety and performance of engineered barrier fluids have improved greatly over the last few decades. 

Step 7: Is the system accessible and easy to operate? 

Human factors are easy to ignore. “It's always been like that” is a common retort and, unfortunately, looking at the equipment is often skipped on rounds too!  No one likes to talk about the unnecessary mechanical seal failures that have happened as a result of this.

Getting a consultation from a vendor who can Design/Build a new seal support system can help solve the problems with ergonomics in hard-to-fit spaces. It’s your best prevention plan. 

This was a long list of things to look at, but it doesn’t have to be hard—especially if you have the support to do the job right the first time. Mechanical seal replacements are expensive and so is downtime. An ounce of prevention with good seal system maintenance and, especially, an expert consultation with a seal support vendor is well worth the effort. 

Achieve Better Mechanical Seal Reliability With Support 

A solid seal support system vendor can help you both with reliability projects for mechanical seals and obtaining the right upgrade or system when needed. Often, your seal support systems don’t need to be completely replaced; a few upgrades can improve performance enough to extend your equipment’s useful lifespan. But, if it does, a top vendor will provide several options to suit both the service and the budget. 

Swagelok’s highly-skilled team of local engineers are available to help you with all your seal system needs. We can be onsite quickly to help with troubleshooting and evaluating seal systems on any pump, not just your biggest problem pumps. If needed, we can design and fabricate anything from small fixes to full replacements in our local Concord, CA shop. Our seal support system Design/Build option means we can also help address unique seal system problems such as ergonomics or human factors of an old installation.  

At Swagelok Northern California, we understand the needs of Bay Area refineries and can help when your mechanical seals need repair—no matter how big or small the issue. Contact our team today by calling 510-933-6200.

About Paul Lesnau | Sales Manager, Business Development Manager, and Field Engineer

Paul holds a B.S. in Mechanical Engineering from North Dakota State University. Before joining Swagelok Northern California, he was the West Coast Regional Sales Manager for an organization based in Illinois involved in pneumatic and hydraulic applications where he supervised product distribution throughout the western United States, Canada, and Mexico. While in this role, he was able to help provide technical and application-specific expertise to customers and distribution to drive specifications.