Abstract: The actual density of liquids is determined with a flexural oscillator that is excited at two different natural vibrations. The presence of air/gas inclusions or other inhomogeneities in a liquid is detected and their influence can be eliminated. In an initial step, the periods of the inherent vibrations and of at least one vibration damping value of the natural vibrations are determined for liquids having different densities ? and viscosities. Liquid densities as well as the difference between them and between the vibration damping values are determined from this. An inclusion-free curve (KB) which reflects the functional dependence F(??) between the relative density differences and the vibration damping differences is calculated and the exact function determined; i.e. the gas/air inclusion-free curve (KB) is expanded by introducing a deviation bandwidth (ab) to form an inclusion-free curve area (KF), which is stored.

Abstract: The actual density of liquids is determined with a flexural oscillator that is excited at two different natural vibrations. The presence of air/gas inclusions or other inhomogeneities in a liquid is detected and their influence can be eliminated. In an initial step, the periods of the inherent vibrations and of at least one vibration damping value of the natural vibrations are determined for liquids having different densities ? and viscosities. Liquid densities as well as the difference between them and between the vibration damping values are determined from this. An inclusion-free curve (KB) which reflects the functional dependence F(??) between the relative density differences and the vibration damping differences is calculated and the exact function determined; i.e. the gas/air inclusion-free curve (KB) is expanded by introducing a deviation bandwidth (ab) to form an inclusion-free curve area (KF), which is stored.

Abstract: A device for determining the density of liquids and gases uses an actuator to physically excite a sample of the material being tested. The oscillations induced by this excitation are detected by a sensor and amplified by an oscillation amplifier, and the amplified signal is used to drive the actuator in a closed-loop fashion. To compensate for errors in the density measurement process arising from non-ideal viscous effects of the sample, a phase change circuit or inverter may be shunted into the amplifier circuit to change the phase of the excitation signal. By observing the effects of the excitation phase change on the oscillation frequency of the sample, the sample's viscosity can be measured, and the system can compensate for its effects.

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: 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: In equipment for drying lengths of materials, in particular lengths of paper, with the length being guided by means of a permeable belt in a semi-circle around a drying drum and being deflected by a guide roller toward a next drying drum which is enveloped in the same manner, with blow boxes being arranged between the drums to supply the drying medium, the improvement comprising means mounting blow-out sections (7) of the blow boxes (3) in a displaceable manner in the radial direction of the drying drums (1, 2) within a frame (12), and means whereby the sections can be returned into their initial positions.

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.