Abstract: A bell-shaped element is placed in a sealed position whereby it rests against the outer wall of the container which is full of solid commodities in order to create a partial vacuum in the inner area of said bell-shaped element and in the gaseous area of the container. A sealing armature subsequently places a sealing cap on top of the opening of the container. When the vacuum is created, a cleanliness element rests against the free edge of the opening of the container in a position which is sealed by means of a liner. The cleanliness element comprises a sieve which retains solid materials inside the container during suction. The cleanliness element subsequently retracts on a plane of its own, wiping the free end of the opening in order to remove debris and solid particles which could prevent the opening from being sealed in a desired manner.

Abstract: A bell-shaped element (1) is placed in a sealed position whereby it rests against the outer wall of the container (9b) which is full of solid commodities (49) in order to create a partial vacuum in the inner area (11) of said bell-shaped element and in the gaseous area of the container. A sealing armature (17) subsequently places a sealing cap (16) on top of the opening (12) of the container. When the vacuum is created, a cleanliness element (32) rests against the free edge (28) of the opening (28) of the container in a position which is sealed by means of a liner (36). Said cleanliness element (32) comprises a sieve (34) which retains solid materials inside the container during suction. The cleanliness element (32) subsequently retracts on a plane of its own, wiping the free end (28) of the opening (12) in order to remove debris and solid particles which could prevent the opening (16) from being sealed in a desired manner.

Abstract: A telephone transducer having a body and a spacer for securing a piezoelectric diaphragm and a printed circuit, wherein the body and the spacer are made with electrically conducting material to carry out the connections between the diaphragm and the printed circuit. The diaphragm can be made of polyvinylidene fluoride or polyvinylidene fluoride copolymer.

Abstract: In a piezoelectric microphone or hydrophone, the elastic structure which reacts directly to the acoustic pressure is formed of piezoelectric polymer. The electroacoustic transducer according to the invention makes use of an elastic structure in the form of a rim clamped plate having at least one incurvation and covered on at least one of its two faces with electrodes connected to an impedance-matching circuit.