Handwritten note "La précision mécanique" — leak test sketches

In this document

The sheet bears the printed or stamped header "La précision mécanique" followed by an address: "11 R. Vergniaud (13 [cut off]" p. 33. The handwritten title "Mesure étanchéité" appears on the page p. 33.

Three dimensioned technical sketches are drawn on it:

• A first diagram, top left, shows two communicating cylindrical tanks filled with liquid, connected by a pipe to an element marked "G". A valve or tap appears on the left, and two vertical liquid level dimensions are noted H and h p. 33.

• A second sketch, on the right, represents an angle bracket supporting a block marked "P", connected to two small vertical elements, with a dimension "d" p. 33.

• A third sketch, at the bottom of the page, shows a cross-section of a fitting or a stuffing box: two elbow pipes entering a hatched block, placed on a surface that is itself hatched, with a rounded central element p. 33.

No detailed legend, numerical values, or dates are legible in the provided transcription.

Context

"La précision mécanique" suggests, by its name, a workshop or a precision mechanical subcontracting company, a type of structure common in the 20th century for the machining of parts intended for the automotive or aeronautical industry. However, nothing in the document confirms a direct link with Citroën.

Leak tests by liquid level difference (here noted H and h) are a classic control principle in fluid mechanics, used in particular to verify the integrity of hydraulic circuits — a central issue for Paul Magès' work on the hydropneumatic suspension, known for its use on the Citroën DS from 1955. This connection, however, remains a perspective external to the document, not information contained within it.

Archivist's view

This sheet, without a date or detailed explanatory text, seems to be a work note or order intended for an external workshop — "La précision mécanique" — for the creation or inspection of a sealing device p. 33.

The principle of measurement by liquid levels (G, H, h) suggests a leak test on a closed circuit, which could be part of Magès' research on the sealing of hydraulic systems, although this cannot be stated with certainty due to the lack of narrative context.

This document could be compared to other technical items from the same collection, such as the Hotchkiss-Laffly 6-wheel vehicle test report, which testifies to contemporary testing activity, although no direct link between the two items is established by the transcriptions.