Abstract: This circuit is suitable for flow tubes (4) the vibration frequency of which is in the order of 1 kHz. A fluid to be measured flows through the tube (4) vibrating in operation at a frequency determined by the density of the fluid. Attached to the tube (4) are electromagnetic vibration sensors (17, 18) positioned at a given distance from each other delivering sinusoidal sensor signals (x17, x18). Impedance-matching devices (31, 32) are fed by the sensor signals. Inputs of an intermediate switch (35) are connected to the outputs of impedance-matching devices. Additional impedance-matching device (33, 34) are fed by outputs of the intermediate switch. Low-pass filters (37, 38) are connected to the outputs of the additional impedance matching devices. The upper cutoff frequency of low-pass filter (37) differs by about 10% to 15% from the upper cutoff frequency of low-pass filter (38). Zero-crossing detector (39, 40) are fed by the outputs of the low-pass filters.

Abstract: A Coriolis mass flow/density sensor which can be installed in a pipe and through which a fluid to be measured flows during operation is balanced over a wide density range so that accurate measurements are possible. The Coriolis mass flow/density sensor includes a measuring tube, an excitation arrangement for exciting the measuring tube to vibrate in a second fundamental flexural mode of vibration; and a counterbalance member attached to the measuring tube which counterbalances the vibration of the measuring tube. A cantilever can be attached to the measuring tube midway between the inlet end and the outlet end of the measuring tube. First and second sensors sense the measuring tube vibration on the inlet and outlet sides of the measuring tube, respectively.

Abstract: These sources are so designed that the amount of power required at turn-on of the DC voltage source is greater than during normal operation, taht the power supply for the evaluation electronics is independent of the measured value, and that the so-called HART protocol can be trans-mitted over the two wires. A first variant of the sources has a first current path, which goes from terminal (P1) via diode (D), the emitter-collector path of transistor (T1), grounded voltage regulator (SR), and grounded current-sensing resistor (Rm) to terminal (P2) of the DC voltage source, and a second current path, which goes from terminal (P1) via diode (D), the emitter-base path of transistor (T1), resistor (R1), the collector-emitter path of transistor (T2), resistor (R2), and resistor (Rm) to terminal (P2). Feedback resistor (Rr) connects terminal (P2) to one of the inputs of operational amplifier (OP) fed by a control signal and the output of which being connected to the base of transistor (T2).

Abstract: This method serves to apply the clamp-on design principle to Coriolis mass flow meters and sensors. A first isolating body (4, 4′) and a second isolating body (5, 5′) having identical masses are fixed to the outside of a pipe (1) or a measuring tube (1′, 10, 10′, 10″) at a predetermined distance L from each other to define a measuring length forming a pipe or tube section (11; 11′; 11″). These masses are substantially greater than the mass of the pipe or tube section. If two measuring tubes are present, clamping bodies (111, 112; 111′, 112′) are used. A vibration exciter (12) attached in the middle of the pipe or tube section excites the latter in a third mode of vibration at a frequency f between 500 Hz and 1000 Hz. The distance L is calculated by the following formula: L=5.

Abstract: Surprisingly, silver-copper-palladium brazing alloys, which have hitherto been used only for the brazing of components of the same material, are also very well suited for brazing directly titanium to stainless steel if, the latter component clasps the titanium component tightly, so that the cold joint is under constant compressive stress. In a method for forming the titanium-steel compound the titanium component is provided with a cylindrical end which has a smaller outside diameter than an adjacent main portion whose external surface is a first surface to be brazed. The cylindrical steel component is a sleeve whose inside diameter is equal to the outside diameter of the main portion and whose internal surface is a second surface to be brazed. A silver-copper-palladium brazing alloy is placed around the end of the titanium component. The steel sleeve is slipped thereover.

Abstract: This sensor for measuring the flow velocity and/or the flow rate of a fluid provides an optical sensor system which is also suitable for use at temperatures higher than 400° C., does not come into contact with the fluid, and requires less space than conventional optical sensor systems. The sensor comprises a tube (1) through which the fluid flows in a first direction and which has a wall (11) in which a first window (2) and a second window (3) of optical, schlieren-free, high-temperature glass are set fluid-tight and pressure-tight at points lying opposite each other along a first tube diameter. A bluff body (4) is disposed along a second tube diameter and fixed in the tube for generating Kármán vortices, whose frequency f is proportional to the flow velocity u. The second diameter is up-stream of, and perpendicular to, the first.

Abstract: To achieve accuracies of the order of 0.75% of the measured value, a digitized, two-dimensional overall image of a bluff body (7), of the internal surface of a measuring tube (2) in the area of the bluff body, of the two fixing zones (71, 72) of the bluff body, and of contour line (51) of the inlet end (5) of the measuring tube is generated by a high-resolution electronic camera (9) located in front of the measuring tube (2) on the axis (3) of this tube. The overall image is divided into three partial images. The first partial image contains only information about the inlet end (5) and the internal surface (4) of the measuring tube, the second contains only information about the bluff body (7) without the fixing zones (71, 72), and the third contains only information about the fixing zones. From shape information about the fixing zones (71, 72) and ideal information characteristic of the ideal shapes of the fixing zones, cross-correlation information is formed.

Abstract: A Coriolis-type mass flow sensor (1) is disclosed which is as insusceptible to external disturbances as possible and which can be installed in a conduit and, during operation, is traversed by a fluid to be measured. The conduit is connected via a fluid inlet (113) and a fluid outlet (114) with a casing (11) in which a rigid support base (12) is disposed. The support base (12) is connected with the casing via at least one mechanical damping element (13, 14, 20). A measuring tube (15) traversed by the fluid ends in the fluid inlet and the fluid outlet. A portion (151) of the measuring tube which is to be set into vibration is attached to the support base by an inlet-side fixing means (121) and an outlet-side fixing means (122). An inlet-side connecting portion (152) of the measuring tube extends from the inlet-side fixing means (121) to the fluid inlet (113), and an outlet-side connecting portion (153) extends from the outlet-side fixing means (122) to the fluid outlet (114).

Abstract: Surprisingly, silver-copper-palladium brazing alloys, which have hitherto been used only for the brazing of components of the same material, are also very well suited for brazing directly titanium to stainless steel if, the latter component clasps the titanium component tightly, so that the cold joint is under constant compressive stress. In a method for forming the titanium-steel compound the titanium component is provided with a cylindrical end which has a smaller out-side diameter than an adjacent main portion whose external surface is a first surface to be brazed. The cylindrical steel component is a sleeve whose inside diameter is equal to the outside diameter of the main portion and whose internal surface is a second surface to be brazed. A silver-copper-palladium brazing alloy is placed around the end of the titanium component. The steel sleeve is slipped thereover.