Caleffi makes steel body, flanged separators to connect to 14 inch pipe sizes. The 548 Series Hydraulic Separator and 549 Series SEP4 Hydraulic, Air, Dirt, Magnetic Separators can handle the largest boiler and chiller applications, up to 2,500 GPM. Our NA546 Series DISCALDIRT Air, Dirt Separators are also available to connect to 14 inch pipe sizes and can handle 4,800 GPM.
Check out this short video of a 14 inch DISCALDIRT on the Caleffi shipping dock, on it's way to a jobsite:
All your examples of hydraulic seperators have the primary and secondary loops currents running counter to one another in the common space (tight junction or yoru 548 series) this has the affect of reducing pressure head in both systems and there fore maximizing cross talk. In particular with a condensing tankless systems where flow in the primary (furnace) loop is important this reduction in flow is problematic. Should not the direction of flow be matched in the shared lumen area?
There is negligible pressure drop in a hydraulic separator and therefor no reduction in flow to the primary (or the secondary). The counter-flow is important for proper mixing when the flow rate in the primary and secondary are not equal (most of the time). Take a look at the explanations in our idronics journal issue #15.