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Kind of a basic question but I'm confused on where the seal is formed in a fluidic fitting (diagram below, source: Idex).

I know as the nut is screwed in, the end of the ferrule contacts the receiving port, forcing the ferrule to compress against the tubing. This results in a seal in the region circled in red because there is a tight fit between the receiving port, ferrule, and tubing. However, is there a seal in the blue region as well? And if so, why? If there is no seal in the blue region, does that mean the small gap in the black region is actually dead volume and fluid can get stuck there?

Diagram referenced in text

Vivek
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1 Answers1

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The seal is on the conical ferrule as you said. The blue tubing portion you circled in black should not be a sealing surface, and in the picture you show it actually appears the blue tube is pushed too far in (too far to the right) to seal properly. If it contacts before or during when the ferrule contacts, it will take compression away from the ferrule. It seems to me the ferrule should be closer to the tube end. I think it's a poor illustration.

This appears like it might be a HiP fitting or similar. You may want to take a look at their website materials.

RC_23
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