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Tri-clamp regenerative displacer: Ø31.8, Ø44.5 and Ø69.9 with 12 slots, 1.5 mm gap
What is a regenerative displacer and what size fits a tri-clamp spool? · Hardware · basis: Spool bore minus a 1.5 mm radial gap (Senft annular-gap regenerator); 16 ga ASME BPE bores 34.8 / 47.5 / 72.9 mm
Long Earth Society build part. The displacers and heads the LES tri-clamp engines are built from. The engines
Exact dimensions. Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part. Mating features
- sizes
- 3 in table
Notes
- An annular-gap regenerative displacer: the 1.5 mm radial gap between it and the spool is the regenerator path, so one spool with this displacer is a complete engine with no separate regenerator section.
- Sizes: 1.5 in Ø31.8 × 75, 2 in Ø44.5 × 90, 3 in Ø69.9 × 120 mm. Wall 1.5 mm, closed rounded end, open at the cap end.
- Twelve radial slots 1.2 mm wide run through the wall over the middle 70 % of the length (from 15 % to 85 % of L); they are the pockets for the regenerator matrix.
- Its cap has a spigot Ø(D − 3) × 3 into the shell, a Ø D × 1.5 flange and a Ø16 × 6 boss with the Ø3 rod hole; 10.5 mm overall.
Sizes
| spool_in | bore_mm | displacer_od_mm | length_mm | radial_gap_mm | slots |
|---|---|---|---|---|---|
| 1.5 | 34.8 | 31.8 | 75 | 1.5 | 12 |
| 2 | 47.5 | 44.5 | 90 | 1.5 | 12 |
| 3 | 72.9 | 69.9 | 120 | 1.5 | 12 |
Mating features
Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| displacer OD in the spool bore | bore − 2 × 0.6 / 0.75 / 1.0 | tri-clamp-spool bore | designed | displacer-* |
| regenerative displacer OD in the spool bore | bore − 2 × 1.5 | tri-clamp-spool bore | designed | displacer-regenerative-* |
| regenerative cap spigot in the shell | shell bore (bore − 6) | regenerative displacer shell | slide | displacer-regenerative-cap-* |
| regenerative cap rod hole | Ø3 | Ø3 displacer rod | slide | displacer-regenerative-cap-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Long Earth Society | Tri-clamp Stirling engine builds | web, video | LES site |
| James R. Senft | An Introduction to Low Temperature Differential Stirling Engines (displacer and gap design) | book | Moriya Press verify |
| Wikipedia | Stirling engine | web | CC BY-SA 4.0 (text) |
Free files
★ Free files 6 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| displacer-regenerative-1.5in-75 | 1.5 in annular-gap regenerative displacer Ø31.8 × 75: 12 radial slots for regenerator mesh, 1.5 mm radial gap | STEP · STL |
| displacer-regenerative-cap-1.5in | cap for the 1.5 in regenerative displacer: Ø28.8 × 3 spigot, Ø31.8 × 1.5 flange, Ø16 × 6 boss with the Ø3 rod bore and an M3 grub (Ø2.5 tapped) at 8 mm | STEP · STL |
| displacer-regenerative-2in-90 | 2 in annular-gap regenerative displacer Ø44.5 × 90: 12 radial slots for regenerator mesh, 1.5 mm radial gap | STEP · STL |
| displacer-regenerative-cap-2in | cap for the 2 in regenerative displacer: Ø41.5 × 3 spigot, Ø44.5 × 1.5 flange, Ø16 × 6 boss with the Ø3 rod bore and an M3 grub (Ø2.5 tapped) at 8 mm | STEP · STL |
| displacer-regenerative-3in-120 | 3 in annular-gap regenerative displacer Ø69.9 × 120: 12 radial slots for regenerator mesh, 1.5 mm radial gap | STEP · STL |
| displacer-regenerative-cap-3in | cap for the 3 in regenerative displacer: Ø66.9 × 3 spigot, Ø69.9 × 1.5 flange, Ø16 × 6 boss with the Ø3 rod bore and an M3 grub (Ø2.5 tapped) at 8 mm | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=tri-clamp-regenerative-displacer
How it fits
Goes in or on
Tri-clamp spool, 1.5 and 2 inchØ44.5 in the Ø47.5 bore, 1.5 mm radial gapConnects to
Tri-clamp crank headØ3 rod through the cold-end headAlternatives
Tri-clamp displacerplain displacer with a separate regeneratorAlso needed
Regenerator matrix disc Ø44 / Ø32 × 0.5 mmmatrix in the 12 slotsIn these build lists
Beta Stirling, rhombic drive, 2 in tri-clampDisplacer and piston in one bore, driven by two counter-rotating gears on a rhom…You might also need
Questions
What is a regenerative displacer?
A displacer whose gap to the cylinder is the regenerator: here a 1.5 mm radial gap with 12 slotted pockets in the wall, so the gas passes the matrix every stroke.
What size regenerative displacer for a 2 inch spool?
Ø44.5 × 90 mm in the Ø47.5 bore, 1.5 mm radial gap.
How big are the slots?
1.2 mm wide, through the 1.5 mm wall, 12 around, over the middle 70 % of the length: 63 mm on the 2 in displacer.