Contributor: EGC Engineered Solutions
When Rob Garlock, our lead pressure seal design engineer, looked at the valve print he couldn’t believe his eyes. This wasn’t anything close to a typical pressure seal, which usually measures somewhere between 4 to 24 inches. This pressure seal was 45 inches in diameter and was made from asbestos, a material that was outlawed nearly 40 years ago.
The seal fit in a check valve and was designed for the feed water system in the Alamitos Generating Station, Long Beach, California. “It was originally quoted in 2014 but I had to see if we could still make the seal,” said Rob. Turns out that if the diameter had been a quarter inch more, it wouldn’t fit on our equipment. “We also had to make a special fixture to create a diameter that big because a normal fixture just wouldn’t work.”
The customer supplied drawings that showed valve tolerances. “We did our best to match the compression and, based on the way the check valve was designed, there was plenty of space to accommodate a graphite pressure seal,” said Rob. EGC couldn’t make caps for a 45-inch diameter seal, so we had to go with a “Pro” design.
Asked why they chose EGC, Rob responded “On a size like this, options are very limited. The existing seal used a square cross section and asbestos was a banned material. All metal seals use a bevel or an angle to fit with the bonnet, so that was un-useable. That leaves graphite. The conventional process would involve a die formed ring but the cost for the tooling could be 2-3 times the cost of producing one, VSG Pro and the lead-time would be months instead of days. So, the most cost and time effective method for making the pressure seal was to use our proprietary process.”
The product was shipped in a wooden crate to ensure safe transport, was sent via Federal Express and arrived the next day. The process took a week but when it was all said and done, there was no problem with installation or the performance.
Maybe you need a small seal? No problem. But rest assured, even when you need a giant seal, we’ll put our best engineering talents to delivering it. In other words, NO PROBLEM.
EGC is a recognized world leader in the engineering and manufacturing of graphite composites for high-temperature applications in sealing or thermal systems management. The EGC website can be accessed at https://egcgraphite.com/.