Apparatus for the internal depressurization of plastic containers thermoformed by means of blowing and intended for sterile filling

Abstract

The internal depressurization of thermoformed containers (C) is performed by means of the secondary suction circuit of a Venturi meter or ejector (15), the primary circuit of which is passed through by compressed air at pressure values regulated by a proportional valve (19) controlled by an electronic control unit (10) which detects the internal pressure or vacuum of the containers by means of a transducer (9) which is programmed by means of a special apparatus (11) and which, upon reaching of the predetermined vacuum inside the containers, activates means (Z) for closing the end portion of the said thermoformed containers. By means of a barometric sensor (21), the electronic control unit is also able to detect the atmospheric pressure of the working environment of the thermoforming machine, and the said control unit, upon a variation in the atmospheric pressure, automatically corrects the vacuum value associated with operation of the said closing means (Z), following a law whereby the said vacuum varies in an inversely proportional manner with respect to the variations in the atmospheric pressure.

Dependencies are inferred from the claim text.