Abstract: The flexible inner pouch is fixed in a leaktight manner by its neck to a rigid ring having peripheral means for fastening on the neck of a rigid bottle accommodating the flexible pouch and an inner tubular part with means for fastening on a central tubular part of a pump body, a seal ensuring leaktightness between the two tubular parts, independently of the means for fastening the pump on the ring. A circuit for air intake into the volume between the pouch and the bottle may comprise an air passage formed in the pump body and closed by confinement means when the pump is not actuated by operating a plunger.

Abstract: The volume (12) between the deformable container (1) containing the product and the rigid outer container (2) receives outside air, at least when the pump (15) is actuated, via orifices (18, 20) made in the pump body (13) and the neck (17) of the deformable container (1) and via grooves (21) for the passage of air into the neck (16) of the outer container (2). Confinements mechanisms, such as a cap (3) mounted in a leaktight manner on the device, or a seal (4) forming a non-return valve against the orifice (18) for air intake, or, alternatively, a special stop limiting the displacement of the piston (6) of the pump (15), prevent the leakage towards the outside, via the reverse path, of vapors and/or gases which have migrated from the inside of the container (1) into the volume (12) between the containers (1, 2), when the pump (15) is not actuated.