Top 3 Seal Support System Requirements You Need to Know Before Contacting a Vendor
by Paul Lesnau, on 7/21/20 8:45 AM
The API estimates that the average life of a mechanical seal is 3 years. Depending on the age of your pumps—a major factor in decades-old Bay Area refineries— and your operating conditions, your actual experience can vary greatly. If you’re averaging well more than 3 years across all your pumps, kudos to your operations and maintenance personnel! If you’re averaging significantly less, read on—you should be looking at carefully evaluating your seal support system requirements for an upgrade or replacement.
Seal support systems are critical to mechanical seal reliability. They provide lubrication and cooling to reduce heat from friction. As a result, you achieve a better seal environment and a longer seal life. Simply put, the right seal support system is the best preventative measure you can put in place for extending the mechanical seal lifecycle.
But, whether you’re upgrading components on an inadequate seal support system or replacing an outdated seal support system, you are going to need three vital pieces of information before you make that call to the vendor. Here’s what you need to bring to the table.
Required Information for Seal Support System Upgrades and Replacements
Your seal support system vendor wants to help you and they know you are on a tight timeline for getting the project done. They can help you best when you have all the necessary information gathered before reaching out. If you could use some help in evaluating your seal support system requirements, consider a local vendor who can come out to the site or provide ‘virtual engineering’ consultations.
Either way, the vendor will ask three critical questions:
#1 Describe the process conditions.
Recommending the right seal support system begins by helping your vendor understand the operating environment and process conditions. They’ll be looking for information regarding:
Type of pump
Manufacturer, model, and year installed are required to provide details on the pump capacity, best efficiency point (BEP), and age which will help match seal support needs to the specific pump characteristics.
The type, temperature, and pressure at suction and discharge determine the seal system fluids, any cooling needs, and instrumentation needed to design and configure a seal support system that will maintain the proper seal chamber environment.
Infrastructure and services tied to the pump
New or upgraded seal support systems need to be designed in consideration of any space constraints, piping support, availability of process cooling water (PCW) or nitrogen, or access to venting. These constraints, common in Northern California, may influence design and installation costs.
Caveat: No seal support system can compensate for external factors such as poor piping geometry, or vibrations caused by imbalance impeller, misaligned coupling, or worn bearings that shorten mechanical seal life.⇨ Ensure that any external issues potentially impacting mechanical seal performance are remedied prior to upgrading or replacing a seal support system.
#2 What type of mechanical seal?
Seal designs and materials used in mechanical seals continue to evolve. Some of the modern options available include:
Your pump manufacturer or mechanical seal vendor will narrow down the selection and recommend the appropriate arrangement and type of seal for your pump. From the perspective of determining the type of seal support system, there are three mechanical seal categories:
|Type of Seal Support System||Description||Best Use Case|
|Process side (single seal)||Process fluids from the pump discharge flow to the seal chamber to remove heat and prevent process fluid from vaporizing.||Used for non-hazardous pumping processes|
|Double or dual (two seals)||An inboard seal keeps the process fluid within the pump housing. An outboard seal prevents the barrier/buffer fluid/gas from leaking into the atmosphere.||
Used to comply with Bay Area Air Quality Management District (BAAQMD) regulations or emissions requirements
|Atmospheric side or quench (single seal)||An external quench fluid delivered to the seal prevents process fluid crystallization.||Typically used in refineries where a steam quench prevents coking|
The specific type of mechanical seal determines the type of seal support system or “plan” per the API 682 Standard. There are dozens of seal plans to choose from. The details you provide regarding process conditions and seal types help your vendor determine cooling options, tubing dimensions, and compatibility of buffer fluid or barrier gas. In addition, they will look at the potential need for pressurization, venting, or condensing, depending on the seal type.
#3 Is there a history of diagnosed seal failures?
When upgrading seal support components or systems, it’s useful to understand what factors led to past mechanical seal failures. That information helps the vendor identify factors where proper seal support system designs and configurations can remedy ongoing problems. In particular, you should be able to answer these questions:
□ Have seal faces warped, checked, or cracked as a result of the inability of the seal support system to maintain the proper seal chamber temperature?
□ Has leakage been gradual or catastrophic?
□ When do the leaks occur? Are they continuous, intermittent, at pump startup, or only when the pump is stopped?
□ Are there problems with corrosion as a result of aging equipment or changes in process fluids?
□ Has the concentration of particulates increased as a result of process changes?
That’s not a complete list of questions, but it provides the vendor with additional information to fine-tune the seal support system design. Your answers will guide them in determining: required cooling capacity, instrumentation to monitor system performance, methods to handle particulates, and location of drains and vents for easier maintenance.
If your current vendor isn’t inquiring about these factors, you’re not likely to get the right seal support solutions. However, with a thorough understanding of your requirements, an experienced vendor can design and deliver seal support systems that extend mechanical seal life well beyond the three-year average.
Swagelok Transforms Seal Support System Requirements Into Solutions
At Swagelok, we’re prepared to take your seal support system requirements and transform them into solutions that maximize the life of mechanical seals and the reliability of pumps. We carry a multi-million dollar inventory of best-in-class parts and components right here in the California Bay Area. Our certified technicians can design, fabricate, and test seal support systems customized to your specific needs.
Having worked with hundreds of Bay Area refinery clients during my career at Swagelok, I welcome the opportunity to meet with you, understand your requirements, and deliver seal support systems that provide the level of reliability you need. After you see our level of service, there’ll be no need to convince you that there’s no better partner than Swagelok.
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.