{
 "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-through-rod-membrane",
 "name": "Tri-clamp membrane with a centre hole: 2 in, for a rod through the diaphragm",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Stirling & thermoacoustic",
 "year": null,
 "question": "How does a displacer rod pass through a diaphragm power piston?",
 "tags": [
  "membrane",
  "diaphragm",
  "through rod",
  "gasket",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "diaphragm with centre hole",
  "rod through diaphragm",
  "tri clamp membrane centre hole",
  "beta diaphragm rod pass through"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/tri-clamp-through-rod-membrane/",
 "sheet_txt": "https://xemstudio.com/objects/tri-clamp-through-rod-membrane/sheet.txt",
 "sheet": {
  "basis": "The 2 in membrane on this site (ISO 2852 Type B section for the clamped ring, 1.0 free span, 3 × Ø2.4 on Ø13) with a Ø5 centre hole; travel and stretch from the sealed generator's crank",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The same membrane as the 2 in diaphragm membrane on this site: Type B bead 5.5 thick from the bore (Ø47.5) to the groove diameter (Ø56.5), web 1.7 out to Ø63, free span 1.0 thick, three Ø2.4 holes on Ø13. It adds a Ø5 hole in the centre, so a Ø3 rod passes through without touching it.",
   "Clamped between the crosshead hub (crankcase side) and the tapped backing disc (working side), the free span runs from Ø20 to Ø47.5 (13.75 mm). At ±6.0 mm travel it forms a 23.6° cone and stretches 9.1 %.",
   "On the sealed generator it carries only the difference between the working space and the crankcase: at most 0.60 bar in the Schmidt estimate at 2 bar gauge charge, about 0.47 bar at the ends of travel, a membrane force of about 1.4 N per mm at the disc edge there.",
   "The seal at the centre is the clamp between the two discs; the rod's own seal is the 15 mm guide bore in the crosshead hub above it."
  ],
  "table": {
   "columns": [
    "size_in",
    "od_mm",
    "bead_to_mm",
    "free_span_dia_mm",
    "free_t_mm",
    "centre_hole_mm",
    "screw_circle_mm",
    "travel_mm",
    "stretch_pct"
   ],
   "rows": [
    [
     "2",
     63,
     56.5,
     47.5,
     1,
     5,
     13,
     "±6.0",
     9.1
    ]
   ]
  }
 },
 "sheet_text": "Tri-clamp membrane with a centre hole: 2 in, for a rod through the diaphragm — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tri-clamp-through-rod-membrane/  (CC BY 4.0)\nBasis: The 2 in membrane on this site (ISO 2852 Type B section for the clamped ring, 1.0 free span, 3 × Ø2.4 on Ø13) with a Ø5 centre hole; travel and stretch from the sealed generator's crank\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The same membrane as the 2 in diaphragm membrane on this site: Type B bead 5.5 thick from the bore (Ø47.5) to the groove diameter (Ø56.5), web 1.7 out to Ø63, free span 1.0 thick, three Ø2.4 holes on Ø13. It adds a Ø5 hole in the centre, so a Ø3 rod passes through without touching it.\n- Clamped between the crosshead hub (crankcase side) and the tapped backing disc (working side), the free span runs from Ø20 to Ø47.5 (13.75 mm). At ±6.0 mm travel it forms a 23.6° cone and stretches 9.1 %.\n- On the sealed generator it carries only the difference between the working space and the crankcase: at most 0.60 bar in the Schmidt estimate at 2 bar gauge charge, about 0.47 bar at the ends of travel, a membrane force of about 1.4 N per mm at the disc edge there.\n- The seal at the centre is the clamp between the two discs; the rod's own seal is the 15 mm guide bore in the crosshead hub above it.\n\nsize_in  od_mm  bead_to_mm  free_span_dia_mm  free_t_mm  centre_hole_mm  screw_circle_mm  travel_mm  stretch_pct\n2  63.0  56.5  47.5  1.0  5.0  13.0  ±6.0  9.1\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, 1 parts): https://xemstudio.com/files/hardware/tri-clamp-through-rod-membrane/index.json\nAPI: https://xemstudio.com/api/geometry?object=tri-clamp-through-rod-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-membrane",
  "tri-clamp-diaphragm-crosshead",
  "tri-clamp-cups",
  "sanitary-clamp-crosses",
  "list-tri-clamp-sealed-diaphragm-generator"
 ],
 "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": "clamped ring",
   "exact": "Type B section: bead 5.5 to Ø56.5, web 1.7 to Ø63",
   "mates": "ISO 2852 face recesses of the hot head and the cross",
   "fit": "clamp",
   "files": "all"
  },
  {
   "feature": "centre hole",
   "exact": "Ø5",
   "mates": "Ø3 displacer rod (no contact)",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "screw holes",
   "exact": "3 × Ø2.4 on Ø13",
   "mates": "M2 × 6 (ISO 273 medium clearance)",
   "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 hole in the membrane?",
   "a": "The displacer sits under the membrane in the same tube, so its rod has to come up through the membrane's centre to reach the crank."
  },
  {
   "q": "Does the hole leak?",
   "a": "The hole is inside the clamped centre: the discs seal it. The only path for gas is along the rod in the crosshead's 15 mm guide bore."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "membrane-2in-hole5",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-through-rod-membrane/membrane-2in-hole5.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-through-rod-membrane/membrane-2in-hole5.stl",
   "note": "2 in flat membrane with a Ø5 centre hole: 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"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tri-clamp-through-rod-membrane/index.md"
}