Abstract: A thermal mass flow-meter used in particular for corrosive and hot gases. It includes a flow duct having at least two measuring resistors. At least one of these is arranged in the flow cross-section. At least one heat source is provided in the zone of influence of the measuring resistors; heat source and measuring resistance may be identical. For the purpose of obtaining long-term resistance to corrosion accompanied by great sensitivity as regards response, the measuring resistors consist of a thin-film resistor with a ceramic insulating member, a measuring resistor is connected to a ceramic support member by way of glass solder, and the support member is in turn connected to the flow duct by way of a glass solder element.

Abstract: In a friction bearing system for a rapidly rotating shaft of an apparatus for measuring the optical absorption of a sample under analysis by way of an optical radiation source projecting a beam on the sample, the chopper system for the periodical interruption of the beam includes a rotatably mounted chopper disk provided with light-admitting openings and a controlled-speed drive system, as well as a radiation detector for the light affected by the sample. Both ends of the shaft fixedly joined to the chopper disk are provided with pivots corresponding to bushes, one of which is held by a spider which is affixed to the housing part that holds the other bush. The spider is provided with a bore running at an angle to the shaft, and the longitudinal axis of this bore intersects the axis of rotation of the shaft. A magnet is held for longitudinal displacement in the bore and its field acts upon a ring disposed on the shaft in order to assure the quiet and wear-free spinning of the chopper disk.

Abstract: Cell for gas analyzers, having a casing with a cylindrical bore which is divided by an axial wall of separation into two chambers. The one chamber serves for the gas being measured and the other for a reference medium. The chambers terminate in windows at both ends. To make such a cell resistant to pressure and corrosion, the reference medium is constituted by a transparent, glass-clear material which is disposed in the cylindrical bore. At each end of the cylindrical bore there is provided an annular shoulder for the support of an annular gasket and a window. The windows are held by annular compression flanges and annular gaskets.

Abstract: A cuvette for optical gas-analysis apparatus, having an elongated metallic housing with two end-faces, two chambers which are parallel to the longitudinal axis and have radiation-reflecting wall surfaces and which are separated from each other by a partition. One of the chambers is for holding a gas under investigation and the other is for holding a reference gas. The chambers are closed off at the end-faces of the housing by radiation-penetrable windows made of a material from the group consisting of calcium fluoride and barium fluoride and which are each initially connected by glass solder to an intermediate frame, which is connected to the housing. The intermediate frame has a U-shaped cross-section and is composed of a metal from the group consisting of gold, silver and aluminum and the intermediate frame is connected, to the windows and to the housing by glass solder.