Abstract: A laser device with one or more active regions, such as quantum wells, gain/lighting media, or other devices, and one or more non-absorbing regions, may be formed by a first growth run (growing a first semiconductor layer), then performing selective, shallow-depth etching, and then a second growth run (growing a second semiconductor layer). The laser device may include a first portion, one or more active regions located on the first portion, and a second portion located on the active region(s). A third portion may be located on one or more ends of the first portion and on the second portion. The third portion may be formed during the second growth run, after the etching step. The non-absorbing region(s) may be formed by the third portion and the end(s) of the first portion. If desired, the non-absorbing region(s) may be produced without annealing or locally-induced quantum well intermixing.

Abstract: A self-priming pump is described that has a housing, an inlet, and an outlet. A first impeller has a first pump section that is arranged in a first chamber, and a second impeller has a second pump section that is arranged in a second chamber. A shaft section is provided between the pump sections, and has a shaft end and penetrates an opening in a housing wall. To improve the net positive section head of the pump, the shaft section between a constriction and the shaft end is formed to taper from the shaft end toward the constriction, and the first impeller and shaft section between the constriction and first pump section has a smooth contour.

Abstract: An impeller for a centrifugal pump that includes a housing, an inlet, an outlet, and a chamber in the housing and in fluidic contact with the inlet and the outlet is described. The impeller is rotatably accommodated in the chamber, and a gap is between a rear side of the impeller and a housing wall. To improve the compatibility with media forming deposits, the impeller has at least one scraper that is integrally bonded at a first position and a second position to the impeller. The first position and the second position are at a distance from each other, and a cleanable clearance is in this space between the scraper and the rear side of the impeller.

Abstract: A self-priming pump is described that has a housing, an inlet, and an outlet. A first impeller has a first pump section that is arranged in a first chamber, and a second impeller has a second pump section that is arranged in a second chamber. A shaft section is provided between the pump sections, and has a shaft end and penetrates an opening in a housing wall. To improve the net positive section head of the pump, the shaft section between a constriction and the shaft end is formed to taper from the shaft end toward the constriction, and the first impeller and shaft section between the constriction and first pump section has a smooth contour.

Abstract: A process is disclosed for switching without leaks a double seat valve comprising radial sealing elements shaped in a slide-shaped closure member (3). In order to ensure leakfree switching, in a first embodiment of the process, radial sealing elements (1, 1*) are guided and remain sealed in a cylindrical valve seat surface (5) while the valve is opened. Sealing elements (2, 2*) provided in a second closure member (4) sealingly engage an end section (E) of the radial sealing elements (1, 1*) and the end section (E) is sealing surrounded by the sealing means (2) when the valve is further opened and when it reaches its open position.