{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "thermoacoustic-hot-cavity-liner",
 "name": "Thermoacoustic hot-cavity liners: Ø47.5 / Ø44 tubes that set a 40 mm hot exchanger flush with a closed hot end's face",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Thermoacoustic & fluidyne",
 "year": null,
 "question": "How do I hold a hot heat exchanger at the top of a closed tri-clamp hot end?",
 "tags": [
  "thermoacoustic",
  "hot cavity",
  "liner",
  "spacer",
  "hot end",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "thermoacoustic hot cavity liner",
  "hot exchanger spacer tri clamp",
  "closed end spool liner"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 4,
 "url": "https://xemstudio.com/objects/thermoacoustic-hot-cavity-liner/",
 "sheet_txt": "https://xemstudio.com/objects/thermoacoustic-hot-cavity-liner/sheet.txt",
 "sheet": {
  "basis": "Design values: lengths = the hot section's inside depth (length − 3 mm closed end) − four 10 mm hot exchanger discs",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A plain tube that stands on the inside of a closed 2 in hot end and holds the hot heat exchanger at its top, so the exchanger's top face is flush with the hot end's clamp face. The stack in the next section then stands on the exchanger, across the hot joint.",
   "Bore Ø44: the gas inside the liner is the engine's hot cavity, the gas spring at the hot end that sets how much the gas moves through the stack. Outside Ø47.5: the spool bore, a slide fit.",
   "It runs at the hot end's temperature: it has to take that temperature. The file is the geometry; what it is made of is the builder's choice."
  ],
  "table": {
   "columns": [
    "part",
    "hot section",
    "section length_mm",
    "inside depth_mm",
    "liner_mm",
    "hot exchanger above_mm"
   ],
   "rows": [
    [
     "ta-hot-liner-2in-17",
     "cup-2in-60",
     60,
     57,
     17,
     40
    ],
    [
     "ta-hot-liner-2in-47",
     "cup-2in-90",
     90,
     87,
     47,
     40
    ],
    [
     "ta-hot-liner-2in-77",
     "cup-2in-120",
     120,
     117,
     77,
     40
    ],
    [
     "ta-hot-liner-2in-109.4",
     "closed-spool-2in-152.4",
     152.4,
     149.4,
     109.4,
     40
    ]
   ]
  }
 },
 "sheet_text": "Thermoacoustic hot-cavity liners: Ø47.5 / Ø44 tubes that set a 40 mm hot exchanger flush with a closed hot end's face — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/thermoacoustic-hot-cavity-liner/  (CC BY 4.0)\nBasis: Design values: lengths = the hot section's inside depth (length − 3 mm closed end) − four 10 mm hot exchanger discs\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A plain tube that stands on the inside of a closed 2 in hot end and holds the hot heat exchanger at its top, so the exchanger's top face is flush with the hot end's clamp face. The stack in the next section then stands on the exchanger, across the hot joint.\n- Bore Ø44: the gas inside the liner is the engine's hot cavity, the gas spring at the hot end that sets how much the gas moves through the stack. Outside Ø47.5: the spool bore, a slide fit.\n- It runs at the hot end's temperature: it has to take that temperature. The file is the geometry; what it is made of is the builder's choice.\n\npart  hot section  section length_mm  inside depth_mm  liner_mm  hot exchanger above_mm\nta-hot-liner-2in-17  cup-2in-60  60.0  57.0  17.0  40.0\nta-hot-liner-2in-47  cup-2in-90  90.0  87.0  47.0  40.0\nta-hot-liner-2in-77  cup-2in-120  120.0  117.0  77.0  40.0\nta-hot-liner-2in-109.4  closed-spool-2in-152.4  152.4  149.4  109.4  40.0\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Xem Studio: tools/gen_ta_modular.py: the section geometry, the network model and every number on these pages — code — CC BY 4.0 — https://xemstudio.com/\n- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 4 parts): https://xemstudio.com/files/hardware/thermoacoustic-hot-cavity-liner/index.json\nAPI: https://xemstudio.com/api/geometry?object=thermoacoustic-hot-cavity-liner\n",
 "sources": [
  {
   "publisher": "Xem Studio",
   "title": "tools/gen_ta_modular.py: the section geometry, the network model and every number on these pages",
   "url": "https://xemstudio.com/",
   "formats": [
    "code"
   ],
   "license": "CC BY 4.0",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine builds",
   "url": "https://longearthsociety.com/engineering/",
   "formats": [
    "web",
    "video"
   ],
   "license": "LES site",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "list-ta-modular-free-piston-2in",
  "tri-clamp-closed-end-spool",
  "tri-clamp-cups",
  "thermoacoustic-heat-exchanger",
  "thermoacoustic-bore-spacer"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [
  {
   "feature": "outside",
   "exact": "Ø47.5",
   "mates": "closed hot cup / closed-end spool bore Ø47.5",
   "fit": "slide",
   "files": "all"
  },
  {
   "feature": "inside",
   "exact": "Ø44",
   "mates": "hot cavity gas (no contact)",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "lower end",
   "exact": "flat ring Ø44–Ø47.5",
   "mates": "the cup's closed end (inside floor)",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "upper end",
   "exact": "flat ring Ø44–Ø47.5",
   "mates": "the lowest hot exchanger disc's outer ring",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "length",
   "exact": "17 / 47 / 77 / 109.4",
   "mates": "sets the top hot disc flush with the hot section face",
   "fit": "designed",
   "files": "all"
  }
 ],
 "fit_classes": {
  "press": "stays put: pin, tube, bearing or magnet held by interference. Typical FDM: hole +0.0 to +0.1 mm on diameter.",
  "slide": "assembles by hand and is held by a grub, pinch or clamp: shaft in a hub, rod in a socket, spigot in a bore. Typical FDM: +0.2 mm.",
  "run": "turns or slides in use: pin in a link, rod through a guide. Typical FDM: +0.3 mm.",
  "socket": "large sliding fit: syringe barrel, sleeve, bobbin in a bore. Typical FDM: +0.3 mm.",
  "clamp": "split part that closes on the mating part with screws: make it at size.",
  "designed": "a gap that is part of the design (piston fit option, displacer gap, air gap): do not change."
 },
 "faq": [
  {
   "q": "Why a liner and not a ledge?",
   "a": "A closed-end spool is plain tube inside; a liner standing on the closed end puts the exchanger exactly at the top without any welding or machining of the spool."
  },
  {
   "q": "Which liner for which hot section?",
   "a": "Match the hot section: the table lists the liner for each closed hot end that takes the modular engine's column."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "ta-hot-liner-2in-17",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/thermoacoustic-hot-cavity-liner/ta-hot-liner-2in-17.step",
   "stl": "https://xemstudio.com/files/hardware/thermoacoustic-hot-cavity-liner/ta-hot-liner-2in-17.stl",
   "note": "hot-cavity liner Ø47.5 / Ø44 × 17: stands on the closed end of cup-2in-60 and carries the four hot exchanger discs, whose top is then flush with the face"
  },
  {
   "file": "ta-hot-liner-2in-47",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/thermoacoustic-hot-cavity-liner/ta-hot-liner-2in-47.step",
   "stl": "https://xemstudio.com/files/hardware/thermoacoustic-hot-cavity-liner/ta-hot-liner-2in-47.stl",
   "note": "hot-cavity liner Ø47.5 / Ø44 × 47: stands on the closed end of cup-2in-90 and carries the four hot exchanger discs, whose top is then flush with the face"
  },
  {
   "file": "ta-hot-liner-2in-77",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/thermoacoustic-hot-cavity-liner/ta-hot-liner-2in-77.step",
   "stl": "https://xemstudio.com/files/hardware/thermoacoustic-hot-cavity-liner/ta-hot-liner-2in-77.stl",
   "note": "hot-cavity liner Ø47.5 / Ø44 × 77: stands on the closed end of cup-2in-120 and carries the four hot exchanger discs, whose top is then flush with the face"
  },
  {
   "file": "ta-hot-liner-2in-109.4",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/thermoacoustic-hot-cavity-liner/ta-hot-liner-2in-109.4.step",
   "stl": "https://xemstudio.com/files/hardware/thermoacoustic-hot-cavity-liner/ta-hot-liner-2in-109.4.stl",
   "note": "hot-cavity liner Ø47.5 / Ø44 × 109.4: stands on the closed end of closed-spool-2in-152.4 and carries the four hot exchanger discs, whose top is then flush with the face"
  }
 ],
 "markdown": "https://xemstudio.com/objects/thermoacoustic-hot-cavity-liner/index.md"
}