Essentia / Devices / Colonoscope

Device Lab 35

Colonoscope

Room air is drawn through an intake filter by a diaphragm pump inside the light source, held at a delivery pressure by a mechanical relief, and vented continuously past a hole in the air and water valve until somebody covers the hole. There is no flow measurement anywhere in the path and no setting except a two- or three-step pump speed.

Also called: Colonoscopy. Arabic: منظار القولون. Device Lab 35 of 69 in BMEssentia Medical City, 2 configurations.

Overview: the configurations

How it works: the main parts

What each part does, from the Colonoscope lessons in the 3D Device Lab.

Distal tip face and the only end that matters

A flat disc of moulded polymer thirteen point two millimetres across, on the end of a tube one thousand six hundred and eighty millimetres long. Four apertures are let into it: an objective window, two illumination windows, and the mouth of the instrument channel.

Bending section, articulation links and the elastomeric sheath

The last hundred millimetres before the tip, and visibly a different thing from the tube behind it: no braid pattern under the surface, a softer feel, and a covering that is rubber rather than the harder polymer of the shaft. It is the only part of the instrument that changes shape on purpose.

Angulation wires, coil pipes and the travel they carry

Four stranded steel wires, each running the whole length of the instrument inside its own close-wound coil pipe, positioned on the diagonals of the cross-section about four point five millimetres out from the centre. At the far end they terminate on the last articulation ring.

Angulation knobs, drums and the friction brakes

Two coaxial discs on one face of the control body, the larger one outboard for up and down and the smaller one inboard for left and right, each with three raised lugs so a thumb can find and turn it without looking. Outboard of each sits a small lever, which is a friction brake.

Counter-wound braid, helical band and the torque path

Two layers under the outer sheath that you can feel through it rather than see: a flat metal strip wound in a long helix, and over that a woven mesh of fine wires laid in both directions at once. Together they are about seven tenths of a millimetre thick and they are the reason the instrument can be steered by twisting it.

Insertion tube wall, the stiffness gradient and the depth graduations

One thousand six hundred and eighty millimetres of grey tube thirteen point two millimetres across, with black rings printed on it at every hundred millimetres from two hundred onwards. It is noticeably floppier near the tip than near the handle if you flex it along its length.

Variable-stiffness adjuster and the coil it tensions

A knurled collar at the base of the control body, just above where the insertion tube leaves it, with a scale marked nought to three on it. Turning it makes the shaft measurably firmer along most of its length, and it is the only control on the instrument that changes the instrument rather than pointing it.

Instrument and suction channel, and 1.78 metres of it

A single lumen three point seven millimetres across running one thousand seven hundred and eighty millimetres from the distal face to a junction inside the control body, where it becomes two branches. It is the largest thing inside the wall and the only one anything solid ever goes down.

Explore it in the Device Lab

• Two functions of one unobservable, and both of their zeros: Leave everything alone and move only the wrap. Read the force factor and the advance factor at nothing, at a quarter turn, at a half, at three quarters, at a full turn, and past it.
• One reading, two tip states, and a factor of three and a half: Set the wrap to nothing and the push to five newtons, and read the tip force. Then set the wrap to one complete turn, leave the push at five newtons, and read it again.
• A load that falls as the square of a length nobody measures: Set the push to one newton and sweep the free span from a hundred millimetres to eight hundred, watching the critical load and the signature.
• Two gases, two different orders of kinetics: This experiment is the comparison. Set the same distension on both configurations and read the gradient, the absorption rate, the floor and the standing load.
• Three bounds, and one of them rewards doing less: Three experiments on the reprocessing chain, and each of them produces a number rather than a description.

Common faults and what to check

Most reported device problems (FDA MAUDE)

Raw counts of adverse event reports for this device type (FDA product code FDF), all years. Not adjusted for the number of units in use, so they show what gets reported, not failure rates. Report text is never copied.

Planned maintenance checks

From the BMEssentia procedure library: every 12 months, about 60 minutes, electrical class I, applied part type BF.

Same programme as other flexible endoscopes: leak test, angulation, channels, traceable reprocessing.

Test instruments: Leak tester; Electrical safety analyser.

Standards engineers test against

Recent FDA recalls

From the FDA recall database (openFDA), newest first, imported 2026-10-22. 25 recalls on record for this device type. Recall text is the FDA's public text; each recall links to the official record.

Learn it, see it in 3D, ask about it

• Ask Essentia about the Colonoscope: answers from named sources, with the device open in its 3D Device Lab beside the answer.
• The Colonoscope on the BMEssentia Platform: the Device Library course, 13 sections from physics to maintenance.
• BMEssentia Medical City: Device Lab 35, the Colonoscope fully assembled in 3D, with lab tasks and the simulations.

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