Tri-clamp closed-end spool: 2 in × 152.4 mm (6 in) with a welded closed end, the hot end of a pressurised Stirling — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/tri-clamp-closed-end-spool/  (CC BY 4.0)
Basis: Fabrication spec: a standard 2 in ferrule (ISO 2852 face, as the ferrule on this site) on BPE 2 in tube Ø50.8 × 1.65, closed at the far end by a 3 mm welded end; plain outside (heat exchangers clamp on, see the fin sleeve)
Catalog version: 2026-10-20

Sizes: see table below
- Drawing to send to a sanitary fabricator: '2 in × 152.4 mm closed-end spool, one 2 in clamp ferrule, tube Ø50.8 × 1.65, closed end 3 mm, 1.5 outside round'. The face is a standard 2 in clamp face; the rest is plain tube.
- On the free-piston generator it is the hot end: the burner fires at its closed end and lower half, and the only joint is at the top, at the regenerator's cold end, so no gasket is near the flame.
- Inside it are the displacer liner, the heater insert, the regenerator screens and the displacer's hot end. The bore is a slide fit for the liner's spokes and the inserts.
- At the generator's relief setting (15 bar gauge) the tube's hoop stress is 23.0 MPa; whether that is acceptable at the hot-end temperature depends on what the spool is made of, which is the builder's check.

feature  value
face  ISO 2852, 2 in (Ø64 flange, Ø56.5 groove, 1.6 recess)
tube  Ø50.8 × 1.65 (bore Ø47.5)
face to outer end  152.4
closed end  3.0, 1.5 outer round

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- ISO (via iTeh sample): ISO 2852 clamp liners: face profile and flange / groove diameters — PDF — standard excerpt; dimensions are facts — https://cdn.standards.iteh.ai/samples/7850/eb49c396488d408c8ced3e2961d76cf3/ISO-2852-1974.pdf
- ASME: BPE Bioprocessing Equipment (tube OD and wall, clamp fittings) — standard — ASME; dimensions are facts [verify license at link] — https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment
- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/tri-clamp-closed-end-spool/index.json
API: https://xemstudio.com/api/geometry?object=tri-clamp-closed-end-spool