Abstract: An apparatus for hardening the inside contour of a gun barrel (1) with laser radiation, which apparatus includes a laser, a laser head (10) that can be disposed to be displaced along the bore axis (4) of the gun barrel (1), and beam-deflecting optics (17) disposed in the laser head so that the laser radiation can be coupled into the muzzle of the gun barrel (1) and guided perpendicularly to the inside surface (5) of the gun barrel (1) by the beam-deflecting optics (17). To harden the gun barrel (1) with high precision and homogeneity, and make available a processing space that is relatively large in comparison to known apparatuses, an ND:YAG laser is used as the laser, and, due to the shorter wavelength in comparison to CO.sub.2 lasers, a glass or optical fiber (11) is used for transmitting the laser beam to the laser head. Moreover, the laser head (10) is secured to a drawing rod (3) that can be centered within the gun barrel (1) and displaced in the direction of the bore axis (4) of the gun barrel (1).

Abstract: A filter particularly for infusion and transfusion apparatus, comprises a housing having an inlet passage and a discharge passage spaced from the inlet passage. The housing includes a surface with a spiral flow passage defined thereon which is centrally communicated to the discharge passage. A filtering material is placed over the spiral in the housing which is made up of two parts which are interconnectable at the location of the spiral and which also act to hold the filter material in position. In an alternate embodiment, the housing of the filter is formed as a portion of a cannula. The inlet and outlet flow passages of the housing may be arranged to align axially, for example, on one side of the housing, or they may be offset.