Principle of the hydraulic pressure regulator (7 October 1953)

In this document

A two-part handwritten note

The document explains the operation of the hydraulic pressure regulator (conjoncteur-disjoncteur), a valve regulating the pump's action on the accumulator.

In the "disconnection" phase (déconjonction), the text describes how valve C₂, initially closed on its seat, allows the pump to discharge towards the accumulator via valve C₃ up to a pressure P of equilibrium between the forces exerted on piston S₁ and on S₂ + R (spring load). A slight rise in pressure then lifts C₂, which causes the pressure on the pump side to drop and breaks the equilibrium: piston S₁ moves "until the pump no longer delivers under pressure" p. 7.

In the "connection" phase (conjonction), the reasoning is reversed: if the pressing force on S₁ decreases, the spring returns C₂ to its seat, causing a progressive throttling of the liquid on this valve, until complete closure. The check valve C₃ then lifts "until the restoration of pressure P", returning to the disconnection principle p. 7.

The D 392-01 diagram

Page 8 bears the technical diagram referenced ACCU — D 392-01, titled "Hydraulic Pressure Regulator". It represents the component in cross-section, with the Reservoir, Pump and Usage inlets/outlets, as well as the elements S1, C2, C3, R and the Accumulator cited in the handwritten note p. 8.

The title block is signed "Perineau", dated 7/10/53 p. 8, and the red handwritten annotation at the top of page 7 bears the same date, "Cart Par 7-10-53" p. 7. The boxes relating to material, treatment or weight are blank.

Context

The pressure regulator (sometimes called a regulator) is, in the history of the Citroën hydropneumatic suspension, the organ that starts or stops the flow of the high-pressure pump to the accumulator according to the circuit pressure — a principle that will notably equip the future DS 19, presented in 1955.

This type of document, dated October 1953, is situated in the technical development phase preceding the commercial launch of the DS, a period when Paul Magès' teams formalized the hydraulic circuit components through numbered drawings ("D" series).

Archivist's perspective

This piece clearly illustrates Magès' conceptual work: a handwritten explanation of the physical reasoning (force equilibrium, throttling) directly accompanying a numbered industrial drawing, intended for the Citroën design office.

It seems that this document belongs to the same design campaign as other pieces in the "Hydraulic components" file, such as the schematic diagram of the DS 19 hydraulic circuit or the note on the self-regulating pump with accumulator, which deal with the same components (pump, accumulator, flow regulation).

The precision of the date (7 October 1953, p. 7-8) and the presence of an identifiable signature make it a valuable dated milestone for reconstructing the chronology of the development of the DS hydraulic circuit.