# Printable tri-clamp (45°): Optical bubble counter for a blow-off line: 5 mm LED break-beam, ¼ in barbs

> How do I count fermentation bubbles electronically (3D printable)?

- Category: Hardware › Printable tri-clamp
- Kind: Hardware
- Basis: Xem Studio design: a small water-filled chamber on the blow-off line; each bubble rising from the inlet tube crosses a beam between a 5 mm IR LED and a 5 mm phototransistor in two Ø5.1 holes; printable 45° back cone
- Page: https://xemstudio.com/objects/printable-tri-clamp-bubble-counters/ · JSON: https://xemstudio.com/api/geometry?object=printable-tri-clamp-bubble-counters · Plain text: https://xemstudio.com/objects/printable-tri-clamp-bubble-counters/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- 3D-printable tri-clamp: this is Xem Studio's print-friendly version of the standard sanitary fitting, drawn so it prints on an ordinary FDM or resin printer with no supports. Download the STL to print it, or the STEP to edit it. The files are true size (no printing allowance): add your own clearance in the slicer or CAD if your printer needs it.
- Run the blow-off hose from the lid barb (through a ½ × ¼ in reducing hose or a ¼ in barb port) into the inlet barb; fill the chamber about 35 mm deep with water or sanitiser so the beam (22 mm up) is under water. Each bubble breaks the beam once: count pulses on an ESP32 input to log the CO₂ rate.
- Print it in a clear material, or seal the LED holes with clear epoxy; mount it upright with two M3 screws through the base.
- Printable tri-clamp: the ISO 2852 face and gasket groove are exactly standard, only the back cone behind each rim is 45° instead of 20°, so no rim overhangs more than 45° from vertical in any print orientation. Join these with the 45° clamps (printable-tri-clamp-clamps) and standard Type B gaskets; a 45° clamp fits only 45° rims, so keep a run all 45°. A 45° cone turns clamp force into face force at 1 : 1 (a 20° cone at 2.7 : 1), so tighten the clamp bolts harder or use M6.
- Print orientation: straight parts face down; elbows, tees and crosses with one face down; horizontal bores bridge their top, so keep them small or add a light tree support inside.
- Every clamp face is the ISO 2852 profile used across this site: 2.85 mm rim, flat face with the gasket groove (K 1.6 deep, R3 1.2 bottom, 23° walls, P2 0.8 edges) on C2, 20° back cone. Flange C3 / groove C2 / tube OD × wall, mm: ½–¾ in 25.0 / 20.4 (derived) / 12.7–19.05 × 1.65; 1–1½ in 50.5 / 43.5 / 25.4–38.1 × 1.65; 2 in 64.0 / 56.5 / 50.8 × 1.65; 2½ in 77.5 / 70.5 / 63.5 × 1.65; 3 in 91.0 / 83.5 / 76.2 × 1.65; 4 in 119.0 / 110.0 / 101.6 × 2.11; 6 in 166.9 (6.570 in) / 156.5 / 152.4 × 2.77; 8 in 217.7 (8.570 in) / 207.0 / 203.2 × 2.77; 10 in 268.5 / 261.0 / 254.0 × 3.40; 12 in 319.3 / 311.8 / 304.8 × 3.40.

## Sizes

| chamber_bore_mm | chamber_h_mm | beam_height_mm | led_hole_mm | barbs |
|---|---|---|---|---|
| 24 | 70 | 22 | 5.1 | ¼ in in / out |

## Where the files are

- GW Kent: [Tri-clamp fittings guide: tube OD, flange OD and ID per size to 12 in; solid cap thickness](https://www.gwkent.com/triclamp-guide) — web — publisher's guide; dimensions cited
- Rubber Fab: [Tri-Clamp gasket dimensional chart: gasket ID, OD and bead diameter per size (2 in bead 2.22 in / 56.50 mm, 1.5 in 1.71 / 43.50, 3 in 3.29 / 83.50)](https://shop.andersonprocess.com/media/assets/product/documents/rubber-fab-tri-clamp-dimensions.pdf) — PDF — maker chart; dimensions are facts (verify at link)

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/printable-tri-clamp-bubble-counters/index.json

- optical-bubble-counter-1-4in-barbs-45: [STEP](https://xemstudio.com/files/hardware/printable-tri-clamp-bubble-counters/optical-bubble-counter-1-4in-barbs-45.step) · [STL](https://xemstudio.com/files/hardware/printable-tri-clamp-bubble-counters/optical-bubble-counter-1-4in-barbs-45.stl) — optical bubble counter: Ø24 × 70 chamber, ¼ in barbs in and out, inlet tube to 10 above the floor, two Ø5.1 LED holes facing across the bubble path 22 up — printable, 45° rims

## Questions

**Can I 3D print this?**

Yes. It is the 3D-printable version: every overhang is 45° or steeper, so it prints without supports, and the sealing face is standard ISO 2852, so a normal gasket and clamp fit.

**What sensor?**

A 5 mm IR LED on one side and a 5 mm IR phototransistor on the other, pressed into the Ø5.1 holes.

## Fits with

- [Optical bubble counter for a blow-off line: 5 mm LED break-beam, ¼ in barbs](https://xemstudio.com/objects/tri-clamp-bubble-counters/)
- [Tri-clamp brewing sensor lids: 4, 6 and 8 in caps with every port a fermenter needs](https://xemstudio.com/objects/tri-clamp-brewing-sensor-lids/)
- [Tri-clamp × hose barb adapters (14MPHR style): ½ to 4 in clamp, ¼ to 4 in hose](https://xemstudio.com/objects/tri-clamp-hose-barb-adapters/)
- [Espressif ESP32-DevKitC](https://xemstudio.com/objects/esp32-devkitc/)
- [Printable tri-clamp (45°): two-bolt clamps, ½ to 8 in](https://xemstudio.com/objects/printable-tri-clamp-clamps/)