# Tri-clamp volume fillers: 2 in tee-run plugs and annular sleeves

> How do I reduce dead volume in a tri-clamp Stirling engine?

- Category: Hardware › Stirling & thermoacoustic
- Kind: Hardware
- Basis: ASME BPE 2 in bore (Ø47.5); ISO 2852 Type B lip reach (2.8 from the joint plane, 1.95 past the face); passage and gap sizes are design values
- Page: https://xemstudio.com/objects/tri-clamp-volume-filler/ · JSON: https://xemstudio.com/api/geometry?object=tri-clamp-volume-filler · Plain text: https://xemstudio.com/objects/tri-clamp-volume-filler/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

**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.

## Notes

- Every cubic centimetre of gas that is not swept and not in a heat exchanger lowers the pressure swing. These plugs fill the parts of the fittings where the gas does no work and leave a defined path through them.
- Tee-run plugs fill the 177.8 mm run of a 2 in tee between the two gasket lips. The blind plug (173.9 long) has a Ø16 passage from one end to the centre and out to the branch; the half beyond the branch is solid, so a capped run end holds no gas. The rod plug has a Ø12 passage end to end so a Ø3 displacer rod passes through it.
- Annular sleeves fill a spool with a 1.0 mm gas gap along the tube wall: the core is Ø45.5, three 3 mm ribs touch the bore. On the hot leg the gap is the heater; on the cold leg the cooler.
- All outer diameters are the bore, Ø47.5: a slide fit (Mating features). The gaps and passages are designed.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| plug OD | Ø47.5 | 2 in tube bore | slide | plug-* |
| sleeve rib tips | Ø47.5 | 2 in tube bore | slide | sleeve-* |
| rod passage | Ø12 | Ø3 displacer rod (no contact) | designed | plug-tee-2in-rod-* |
| flow passages | Ø16 | gas path to the branch | designed | plug-* |
| annular gap | 1.0 | gas gap along the tube wall | designed | sleeve-* |

## Sizes

| file | od_mm | length_mm | passage |
|---|---|---|---|
| plug-tee-2in-blind | 47.5 | 173.9 | Ø16 axial to centre + Ø16 radial |
| plug-tee-2in-rod-106.55 | 47.5 | 106.55 | Ø12 axial through + Ø16 radial |
| sleeve-2in-76.2 | 47.5 | 76.2 | 1.0 annular gap |
| sleeve-2in-32 | 47.5 | 32.0 | 1.0 annular gap |

## Where the files are

- ISO (via iTeh sample): [ISO 2852 clamp liners: face profile and flange / groove diameters](https://cdn.standards.iteh.ai/samples/7850/eb49c396488d408c8ced3e2961d76cf3/ISO-2852-1974.pdf) — PDF — standard excerpt; dimensions are facts
- ASME: [BPE Bioprocessing Equipment (clamp fitting dimensions, tube OD and wall)](https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment) — standard — ASME; dimensions are facts (verify at link)
- Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (4 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/tri-clamp-volume-filler/index.json

- plug-tee-2in-blind: [STEP](https://xemstudio.com/files/hardware/tri-clamp-volume-filler/plug-tee-2in-blind.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-volume-filler/plug-tee-2in-blind.stl) — 2 in tee-run plug Ø47.5 × 173.9: Ø16 passage from one end to the centre, then Ø16 out to the branch; the other half solid
- plug-tee-2in-rod-106.55: [STEP](https://xemstudio.com/files/hardware/tri-clamp-volume-filler/plug-tee-2in-rod-106.55.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-volume-filler/plug-tee-2in-rod-106.55.stl) — 2 in tee-run plug Ø47.5 × 106.55: Ø12 passage end to end for the displacer rod and the gas, Ø16 out to the branch at 19.60 from the bottom
- sleeve-2in-76.2: [STEP](https://xemstudio.com/files/hardware/tri-clamp-volume-filler/sleeve-2in-76.2.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-volume-filler/sleeve-2in-76.2.stl) — 2 in annular sleeve Ø45.5 × 76.2 with three 3 mm ribs to Ø47.5: 1.0 mm gas gap along the tube wall (hot spool)
- sleeve-2in-32: [STEP](https://xemstudio.com/files/hardware/tri-clamp-volume-filler/sleeve-2in-32.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-volume-filler/sleeve-2in-32.stl) — 2 in annular sleeve Ø45.5 × 32 with three ribs to Ø47.5: 1.0 mm gas gap (cold spool, above the regenerator)

## Questions

**Why fill the tee run?**

A 2 in tee run is 315 mL of gas; with the plug only the Ø16 passage and the gaps remain.

**Won't a sleeve block the flow?**

The 1.0 mm gap all round is 146 mm² of flow area, the same order as the Ø16 passage (201 mm²), and it puts the gas against the heated or cooled wall.

## Fits with

- [Sanitary clamp tees and short-outlet tees (7MP, 7MPS): ½ to 4 in](https://xemstudio.com/objects/sanitary-clamp-tees/)
- [Tri-clamp spool (two ferrules on a tube), 1.5 and 2 inch](https://xemstudio.com/objects/tri-clamp-spool/)
- [Sanitary clamp spools: 3, 6 and 12 in, ½ to 4 in](https://xemstudio.com/objects/sanitary-clamp-spools/)
- [Build list: Tri-clamp elbow diaphragm alpha, 2 in](https://xemstudio.com/objects/list-tri-clamp-elbow-diaphragm-alpha/)
- [Build list: Tri-clamp tee diaphragm gamma, 2 in](https://xemstudio.com/objects/list-tri-clamp-tee-diaphragm-gamma/)