Abstract: Pictorial data from a thermal imager is applied on a line to a RAM at which a histogram representing the numerical distribution of pixel values is produced. This is applied to a microprocessor which uses the histogram to produce a transform to control the gain and offset of the data output of the processor. The microprocessor sets a look-up table to apply the transform to the received data, the output of the table being converted to analogue form at an analogue-to-digital converter.

Abstract: A process of packaging goods characterized in that the goods are placed in a container (1) made of flexible thermoplastics sheet material and having a flange (2) provided with an aperture (3), partly closing the container by sealing a deformable sheet material (4) of thermoplastics material to the flange so as to leave unsealed together a part of the flange and the sheet between the aperture and the interior of the container, inserting a conduit member (7) into the aperture so as to separate the unsealed part of the flange and the sheet material, modifying the atmosphere in the container by withdrawing a part of the air in the container and introducing a preserving gas into the container, removing the conduit and sealing together the unsealed part of the sheet material and the flange whereby communication between the aperture (3) and the interior of the container is prevented.

Abstract: A vacuum device comprising a by-pass fan pump, a conduit connecting the inlet of the pump to a member in which pressure is to be reduced and a flow passage formation enabling a stream of air to enter the pump and to by-pass the member. In a preferred embodiment the inlet to the by-pass fan pump is connected to the outlet of a Venturi pump and the member is connected to the exhaust inlet of the Venturi pump. The device is directed particularly to the replacement of air by preserving gases in the packaging of foodstuffs.

Abstract: A valve for use primarily for dispensing liquids from non-reusable containers comprising a conduit formed by bonding a flexible sheet of thermoplastic material to a second sheet of resilient thermoplastics material. The second sheet is of a springy nature and is provided with a shoulder portion directed to the first sheet. The shoulder portion positioned adjacent to a deformable member formed into the second sheet. The conduit is closed by the first sheet being stretched tightly over the shoulder. However by deforming the deformable member towards the first sheet the latter is raised from the shoulder thereby opening the conduit.

Abstract: A process of packaging goods, especially foodstuffs, comprising enclosing the goods in a sheet of thermoplastics material, preferably a bag, so as to form a package which presents two unsealed juxtaposed surfaces. The package is then placed in a container, one wall of which is made of deformable sheet material, preferably a sheet made of a silicone resin, which is stable at the sealing temperature of the thermoplastics material. The container is then connected to a source of vacuum and when the pressure has been reduced in both the container and the bag sufficient heat is applied to the deformable sheet in the vicinity of the juxtaposed surfaces to cause them to become sealed together. In a further embodiment of the invention vacuumization of the container including the bag is followed by the injection of a preserving gas such as carbon dioxide.

Abstract: A process of packaging goods particularly foodstuffs in which the goods are placed in a first container for example a plastics bag or a tray having a deformable lid, sealing the container except for an aperture provided by an open valve. The container is then placed in a second container having rigid walls. A vacuum is then created in both containers after which the inner container is completely sealed by for example closing the valve whilst preventing the entry of undesireable substances. In a preferred process an inert or preserving gas is introduced into the first container prior to sealing.

Abstract: A valve which is to be used as a component of plastics bags and trays for packaging foodstuffs and other perishable goods. The valve consists essentially of a small spherical chamber having an inlet and an outlet. The chamber is made from two hemi-spherical walls having different resilience. In order to close the valve one wall is made to spring into contact with the other wall so that the two walls enter into such close intimate contact that communication between the inlet and the outlet through the valve is prevented.