Top-hat rolling diaphragm, 1.50 in bore, flat flange: the one that clamps in a 2 in tri-clamp joint — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/rolling-diaphragm-top-hat/ (CC BY 4.0) Basis: Published standard sizes and design rules of top-hat rolling diaphragms (Marsh Bellofram design manual 2022); installed shape drawn by Xem Studio from those numbers Catalog version: 2026-10-20 Sizes: see table below - A rolling diaphragm is a fabric-reinforced top hat. Its flange is clamped, its head is clamped to a piston, and the sidewall rolls in a 180° convolution between the piston and the cylinder bore as the piston moves. Nothing slides, so there is no seal friction and no piston fit: the piston and bore are 2.41 mm apart all round. - The flat-flange 1.50 in size has a flange of bore + 1 in = 2.50 in (Ø63.5); the 2 in tri-clamp flange is Ø64.0. So the diaphragm's flange is clamped by a standard 2 in clamp in place of the gasket: between a ferrule's land and the seat ring that sits in the power head's standard face recess (flange 0.51 + ring 1.19 = the 1.7 web of a Type B gasket). - Published numbers for this size: bore 1.50 in (Ø38.10), piston 1.31 in (Ø33.27), convolution 0.095 in (2.41), effective area 1.55 in² (1000 mm², the circle on the mean diameter), heights 0.44 / 0.62 / 0.94 / 1.50 in with maximum half strokes 0.06 / 0.24 / 0.56 / 1.12 in; sidewall ≈ 0.017 in, head and flange 0.020 in; flange radius 1/16 in, piston corner radius 1/16 in. - The file is the 1.50 in high diaphragm as it sits in the power head at mid-stroke: head 15.34 mm below the flange plane, outer wall on the bore, convolution, inner wall on the piston. Over the 20 mm stroke of the power head (head 5.34 to 25.34 mm below the flange, inside the published 28.4 mm) the convolution moves half as far, from 20.0 to 30.0 mm. - Rules from the same manual that the power head follows: the higher pressure must always be on the head side (a reversal, even brief, can fold the sidewall); the piston is guided so it never tips; the bore mouth and piston edge are radiused; the head is clamped between the piston and a retainer smaller than the piston's flat. - The published standard range of this flat-flange style runs from 0.37 to 12 in bore; the next sizes either side are 1.37 in (flange 2.37 in) and 1.62 in (flange 2.62 in), which do not match a tri-clamp flange. - Why not a piston sliding in the tube itself: 2 in sanitary tube is made to its OD (+0.002 / −0.011 in) and wall (0.065 ± 0.008 in), not to its bore, so the bore of one length can be anywhere from 46.8 to 48.0 mm, and it is not round to a sliding-seal standard. A rolling diaphragm runs in its own Ø38.10 bore inside the power head and only needs that bore round within a few tenths. bore_in piston_in convolution_in area_in2 height_in max_half_stroke_in flange_od_in 1.37 1.19 0.09 1.28 1.37 1.0 2.37 1.5 1.31 0.095 1.55 0.94 0.56 2.5 1.5 1.31 0.095 1.55 1.5 1.12 2.5 1.62 1.44 0.09 1.83 1.62 1.25 2.62 1.75 1.56 0.095 2.15 1.75 1.37 2.75 2.0 1.81 0.095 2.85 2.0 1.62 3.0 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - Marsh Bellofram: Rolling diaphragm design manual (2022): nomenclature, height formula, standard-size tables, hardware radii — PDF — publisher's manual; dimensions cited, nothing copied — https://damapi.marshbellofram.com/uploads/Bellofram_Diaphragm_Design_Manual_2022_7a922642c3.pdf - Steel & O'Brien: ASTM A270 sanitary tubing: OD and wall tolerances — web — publisher's table; dimensions cited — https://www.steelobrien.com/products/tubing-hangers-other/sanitary-tubing/astm-a270-tubing-polish-20ra-id-32ra-od/ - 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 - 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 - Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/ Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/rolling-diaphragm-top-hat/index.json API: https://xemstudio.com/api/geometry?object=rolling-diaphragm-top-hat