Review the assumptions first

Start a project

Use the folder button to create, duplicate, select, import, or delete a locally saved project. The included baseline and wider-line candidate are synthetic demonstrations, not hardware recommendations.

Build the path

Open Network and add each meaningful series restriction from chamber to pump. Use measured clear inside diameters and centerline lengths. Enter empirical supplier or measured conductance for valves and custom elements. The long-tube finding warns when a simple relation needs better transmission data.

Enter pump and gas-load data

Open Pumpdown and replace the demonstration curve with pressure-speed points from the correct pump, gas, and operating configuration. Enter the pump's applicable ultimate pressure. On Bench, enter leak load, wetted surface area, and an appropriate outgassing-rate assumption.

Understand an endpoint

• Target reached: the numerical trace crossed the entered target.
• Load floor: entered gas load balances modeled effective speed before the target.
• Pump limit: the trace reached the entered ultimate-pressure boundary.
• Time limit: the bounded integration window ended first.
• Invalid: required inputs are missing or contradictory.

Import and export

Knudsenpath imports project JSON created by Knudsenpath. Export evidence package creates project JSON, component CSV, pump-curve CSV, pumpdown CSV, milestone CSV, sensitivity CSV, a text report, a PDF report, and a SHA-256 manifest. Apple's share sheet controls where those files go.

Troubleshooting

A result does not change

Confirm the edited component is enabled, numeric values are positive, and the pump curve spans the pressure range. Review Preflight for blocked paths, invalid pressure ranges, missing empirical values, and model-boundary warnings.

A target is not reached

Compare the target against pump ultimate pressure and the displayed Q/S floor. Check leaks, outgassing, surface area, pump curve, and line restrictions before changing hardware.

An imported file is rejected

Use an unmodified Knudsenpath project JSON file. A complete evidence package includes other formats for inspection, but only the project JSON is importable.

Engineering boundary

Knudsenpath is a planning and documentation aid. It does not control equipment, certify a design, represent every transitional geometry, replace manufacturer data, or substitute for measured commissioning and qualified engineering review.

Contact support

Include Knudsenpath version 1.0 build 4 or later, device model, iOS or iPadOS version, affected screen, endpoint status, and reproducible steps. Do not email proprietary designs, confidential notes, or complete evidence packages.