AES and AEW floating head heat exchangers are the workhorses of high temperature process duty, and Europe is where the compliance bar is highest. Yuhong Group now supplies PED 2014/68/EU compliant and CE marked floating head shell and tube heat exchangers, with notified body involvement applied where the equipment category requires it. This allows European process plants and skid builders to place these units into service without re-certification, while keeping Category I units on the lower cost self-assessment route.
The floating head exists for one reason: differential thermal expansion. When the shell and the tube bundle operate at materially different temperatures, a fixed tubesheet design transfers that expansion into the tubes and the shell, which means stressed welds and eventual leakage. A floating head lets the bundle move, so the mechanical load is absorbed by the packing or the gasket rather than by the metal.
| Parameter | Range |
|---|---|
| Type | AES, AEW, AJW floating head |
| Design pressure | up to 150 bar |
| Design temperature | -40 to 450 C |
| Shell diameter | 300 to 2,000 mm |
| Tube materials | TP304L, TP316L, duplex, titanium |
| Girth flange | SA182 F304, F316, F11 |
Three issues recur in European tenders for floating head exchangers. First, girth flange and split backing ring tolerances: a bundle that cannot be withdrawn defeats the purpose of the design, so we machine and trial fit the assembly before shipment. Second, documentation language: technical files are issued in English, with German and French translation available for notified body submission. Third, maintenance access: shell nozzles, test rings and lifting lugs are positioned so that the bundle can be pulled without removing adjacent pipework.
For high temperature duty the thermal design is verified in HTRI, and where the client specifies a fouling allowance we calculate the resulting outlet temperature rather than assuming it. Where pressure drop is critical, baffle cut and spacing are adjusted and reported in the design sheet so the mechanical drawing and the process duty stay aligned.
PED certified floating head exchangers ship in 50 to 80 working days depending on notified body scheduling. Yuhong Group supports the conformity assessment process directly, including liaison with the notified body, submission of the technical file and clarification of any design review comments, so that the certificate is issued against the unit actually built rather than a generic design.
No. Involvement depends on the PED risk category, which is assessed per vessel. Category II and above require notified body involvement in the conformity assessment. The applicable module (A2, D1, E1 or higher) determines whether final product inspection, production surveillance, or both apply, so design examination is not automatically required at Category II. Category I units may follow the self-assessment route with a technical file and CE marking.
A floating head lets the tube bundle expand independently of the shell, absorbing differential thermal expansion. This removes the mechanical stress that causes tube and tubesheet weld failures in high temperature differential duty, at the cost of a girth flange and packing.
ASME Section VIII Division 1 or EN 13445 design, TEMA class R or C mechanical standard, NACE MR0175 for sour service, and EN 10204 3.1 or 3.2 material certification can all be combined in a single unit to satisfy multiple market requirements.
