{
 "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": "tri-clamp-diaphragm-membrane",
 "name": "Tri-clamp diaphragm membrane: flat, 1.5 and 2 in clamped size",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Stirling & thermoacoustic",
 "year": null,
 "question": "What size membrane does a 2 inch tri-clamp diaphragm need?",
 "tags": [
  "membrane",
  "diaphragm",
  "gasket",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "tri clamp diaphragm membrane",
  "stirling diaphragm size",
  "diaphragm swept volume",
  "diaphragm membrane 2 inch",
  "membrane gasket tri clamp"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 2,
 "url": "https://xemstudio.com/objects/tri-clamp-diaphragm-membrane/",
 "sheet_txt": "https://xemstudio.com/objects/tri-clamp-diaphragm-membrane/sheet.txt",
 "sheet": {
  "basis": "ISO 2852 Type B gasket section for the clamped ring (bead 5.5 to the groove diameter, web 1.7), ASME BPE bore for the free span; free-span thickness and stretch are design values",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The membrane is drawn flat, as it sits at mid-stroke. Outside the bore it has the Type B gasket section, so it is clamped like a gasket: bead 5.5 thick from the bore out to the groove diameter (Ø43.5 / Ø56.5), web 1.7 out to flange − 1. Inside the bore it is a 1.0 mm free span.",
   "Free span: from the centre-disc edge to the bore, 8.90 mm (1.5 in, Ø17 disc) and 13.75 mm (2 in, Ø20 disc). At the design stroke the span forms a cone of 29.3° / 28.6° and stretches 14.7 / 13.9 %.",
   "Swept volume with a rigid centre disc is the frustum between the disc edge and the bore: V = s · π/3 · (R² + R r + r²); see the table.",
   "Three Ø2.4 holes for the M2 screws that clamp the centre and backing discs."
  ],
  "table": {
   "columns": [
    "size_in",
    "od_mm",
    "bead_to_mm",
    "free_span_dia_mm",
    "free_t_mm",
    "bead_mm",
    "web_mm",
    "disc_dia_mm",
    "annulus_mm",
    "stroke_mm",
    "cone_deg",
    "stretch_pct",
    "swept_ml"
   ],
   "rows": [
    [
     "2",
     63,
     56.5,
     47.5,
     1,
     5.5,
     1.7,
     20,
     13.75,
     15,
     28.6,
     13.9,
     14.16
    ],
    [
     "1.5",
     49.5,
     43.5,
     34.8,
     1,
     5.5,
     1.7,
     17,
     8.9,
     10,
     29.3,
     14.7,
     5.48
    ]
   ]
  }
 },
 "sheet_text": "Tri-clamp diaphragm membrane: flat, 1.5 and 2 in clamped size — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tri-clamp-diaphragm-membrane/  (CC BY 4.0)\nBasis: ISO 2852 Type B gasket section for the clamped ring (bead 5.5 to the groove diameter, web 1.7), ASME BPE bore for the free span; free-span thickness and stretch are design values\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The membrane is drawn flat, as it sits at mid-stroke. Outside the bore it has the Type B gasket section, so it is clamped like a gasket: bead 5.5 thick from the bore out to the groove diameter (Ø43.5 / Ø56.5), web 1.7 out to flange − 1. Inside the bore it is a 1.0 mm free span.\n- Free span: from the centre-disc edge to the bore, 8.90 mm (1.5 in, Ø17 disc) and 13.75 mm (2 in, Ø20 disc). At the design stroke the span forms a cone of 29.3° / 28.6° and stretches 14.7 / 13.9 %.\n- Swept volume with a rigid centre disc is the frustum between the disc edge and the bore: V = s · π/3 · (R² + R r + r²); see the table.\n- Three Ø2.4 holes for the M2 screws that clamp the centre and backing discs.\n\nsize_in  od_mm  bead_to_mm  free_span_dia_mm  free_t_mm  bead_mm  web_mm  disc_dia_mm  annulus_mm  stroke_mm  cone_deg  stretch_pct  swept_ml\n2  63.0  56.5  47.5  1.0  5.5  1.7  20.0  13.75  15.0  28.6  13.9  14.16\n1.5  49.5  43.5  34.8  1.0  5.5  1.7  17.0  8.9  10.0  29.3  14.7  5.48\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- 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\n- ASME: BPE Bioprocessing Equipment (clamp fitting dimensions, tube OD and wall) — standard — ASME; dimensions are facts [verify license at link] — https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment\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, 2 parts): https://xemstudio.com/files/hardware/tri-clamp-diaphragm-membrane/index.json\nAPI: https://xemstudio.com/api/geometry?object=tri-clamp-diaphragm-membrane\n",
 "sources": [
  {
   "publisher": "ISO (via iTeh sample)",
   "title": "ISO 2852 clamp liners: face profile and flange / groove diameters",
   "url": "https://cdn.standards.iteh.ai/samples/7850/eb49c396488d408c8ced3e2961d76cf3/ISO-2852-1974.pdf",
   "formats": [
    "PDF"
   ],
   "license": "standard excerpt; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "ASME",
   "title": "BPE Bioprocessing Equipment (clamp fitting dimensions, tube OD and wall)",
   "url": "https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment",
   "formats": [
    "standard"
   ],
   "license": "ASME; dimensions are facts",
   "license_verified": false,
   "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": [
  "tri-clamp-diaphragm-head",
  "tri-clamp-diaphragm-disc",
  "tri-clamp-gasket",
  "tri-clamp-clamps"
 ],
 "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": "bead",
   "exact": "5.5 thick, Ø34.8–Ø43.5 / Ø47.5–Ø56.5",
   "mates": "face recesses of the ferrule and the head (ISO 2852 Type B section)",
   "fit": "clamp",
   "files": "membrane-"
  },
  {
   "feature": "web",
   "exact": "1.7",
   "mates": "between the two lands",
   "fit": "clamp",
   "files": "membrane-"
  },
  {
   "feature": "free span",
   "exact": "Ø34.8 / Ø47.5 × 1.0",
   "mates": "moves with the centre disc",
   "fit": "designed",
   "files": "membrane-"
  },
  {
   "feature": "screw holes",
   "exact": "3 × Ø2.4",
   "mates": "M2 screws",
   "fit": "designed",
   "files": "membrane-"
  }
 ],
 "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": "How much volume does a 2 in tri-clamp diaphragm sweep?",
   "a": "14.16 mL at 15 mm stroke with the Ø20 centre disc (frustum between Ø20 and Ø47.5)."
  },
  {
   "q": "Why is the membrane drawn flat?",
   "a": "That is its shape at mid-stroke; at the ends of the stroke the free span is a shallow cone either side."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "membrane-2in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-diaphragm-membrane/membrane-2in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-diaphragm-membrane/membrane-2in.stl",
   "note": "2 in flat membrane: Ø63 OD, Type B bead 5.5 thick from Ø47.5 to Ø56.5, web 1.7 out to the OD, free span Ø47.5 × 1.0, 3 × Ø2.4 on Ø13"
  },
  {
   "file": "membrane-1.5in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-diaphragm-membrane/membrane-1.5in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-diaphragm-membrane/membrane-1.5in.stl",
   "note": "1.5 in flat membrane: Ø49.5 OD, Type B bead 5.5 thick from Ø34.8 to Ø43.5, web 1.7 out to the OD, free span Ø34.8 × 1.0, 3 × Ø2.4 on Ø12"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tri-clamp-diaphragm-membrane/index.md"
}