We also manufacture filtering unions. A frit is added to a union into the port fit-in before making the ferrule on the tube. However, when a fitting detail has a frit in it, the port fit-in depth is deeper, so that the port fit-in length from the ferrule nose is still standard. If that tube is used in any other AFP® fitting, it will be exactly the same as an standard union.
Other companies also offer a filtering capability. They make the port fit-in at the same depth as the standard fitting. But when we make the ferrule on the tube, we can see that there is a smaller port fit-in lenght required in these types of union. If someone uses a pre-made tube and ferrule in this union, it will damage the frit and send a lot of small particles into your system. That’s why our filter design remains truly interchangeable.