By Chuck Reed, Senior ICS Sales Specialist
If you are looking for a visual walkthrough of the process, check out this video featuring Ipsen Technical Director Jim Grann that shows the door seal installation process step-by-step.
Door seals, lip seals, or O-rings, are designed with a certain amount of elasticity. That stretchiness helps to make sure the seals are airtight as they are compressed when the door closes and compressed further under vacuum. They have to be able to expand and contract as the temperatures change around the furnace door, and as the chamber goes from vacuum to high-pressure quench. And they need to have some durability for when the occasional loader rubs against the seal, or when a part drops onto the seal.
For those reasons, these seals have the properties of a very large rubber band. Stretchy, compressible, and expandable under tension.
So, installing a lip seal around the opening of a furnace can’t be approached the same way as closing a zip top baggie or sealing a plastic food container. Starting your installation at one point and working your way around the circumference back to the beginning is a surefire way to run into the situation where you end up having quite a bit of seal left that doesn’t appear to fit.
Here are a few key components to making sure the lip seal will fit properly, without mistakenly applying tension and stretching the seal.
First, you want a clean and debris-free channel. Using a clean cloth and denatured alcohol (never acetone), wipe out the groove where the seal will be installed. Make sure there are no remaining particulates that could damage the new seal. You will also want to clean the seal itself using the same method, removing any residual dust or packaging particulates.
Now that the groove and the seal are clean, start installing the seal by remembering North, South, West, then East. Start installing the seal at the top, bottom, left, and right sides without smoothing the whole seal into the groove. By starting installation at each of those four locations, the operator is ensuring that the seal won’t stretch out during the installation, which means not having any excess material gathered in one place.
Then, do one last wipe down of the seal so that any dust or dirt picked up during the installation process has been removed and the seal is clean.
Finally, be sure to use the appropriate type and amount of lubricant. Do not use anything other than the approved lubricant as recommended in your owner’s manual. One of the most common types of lubricant used on the seal is a graphite powder or dust, particularly when the door is rotating to lock into the cams. For non-rotating doors, vacuum grease is typically used.
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