Abstract: Heat insulation is provided for a refrigerator or freezer. The insulation includes a closed cell material, which is placed in a hermetically closed space (13) surrounded by a diffusion-tight shell. The space communicates with a vacuum source, and a gas diffuses through the cells five times faster than air gasses. The material does not achieve its full insulating properties until the refrigerator has been used.

Abstract: This invention relates to an electric refrigerator or freezer. The cabinet comprises one or several hermetically sealed heat insulated spaces (14) which are wall or door panels of the cabinet. The space or spaces communicate with a vacuum creating device (18) via an evacuation conduit (17). A vacuum creating device is a permanently installed unit in the cabinet which is arranged to be activated when or after the cabinet has been installed by the user of the cabinet. After a long period of running the vacuum device creates a suitable underatmospheric pressure in the space or spaces (14).

Abstract: This invention relates to a vacuum pump. The pump includes a pump housing (10) having upper and lower cylindrical, partly liquid filled, compression chambers (11 and 12 respectively) which are separated from each other and in which an upper and a lower part (14, 15) of a piston (12) is movable. The piston has a passage (21) which is provided with a check valve and which provides communication between the upper and the lower chamber (11 and 12 respectively). The upper chamber communicates, via an opening (26) which is provided with a check valve, with a liquid filled de-aeration receptacle (27). The lower chamber (12), during a part of the movement of the piston, via an inlet (33), communicates with the space being evacuated.

Abstract: An arm preferably for electric switches, the arm being controlled by electricity, and having a first fixed end the other end of which is movable perpendicular to the length direction of the arm. The arm comprises two parallel portions (47) separated by an air gap (17) or some other heat insulating material, and which are secured to each other at each end. At least one of the portions, being heated by electricity and, through longitudinal differential expansion with respect to the other portion, achieves said movement. The portions are so shaped that, adjacent the fixed end (at 45) with respect to the rest of the portions, they have a reduced bending resistance about an axis which is perpendicular to the length direction of the arm and with respect to said direction of movement.