Abstract: Process for regenerating a silver catalyst deactivated by coking during the gas phase epoxidation of 1,3-butadiene by reacting the coked catalyst with a gas mixture containing at least 5% by volume of water vapor and up to 95% by volume of oxygen at temperatures of from 100 to 500 .degree. C.

Abstract: The invention is directed to a method for manually measuring a workpiece with a manually guided coordinate measuring apparatus. The apparatus includes a carrier for a probe which, in turn, carries a probe ball 12 on a deflectable probe pin 11. The carrier is movably journalled in several spatial directions. The probe ball 12 is brought into contact with the geometric element of the workpiece 30' to be measured and is guided therealong in continuous contact therewith. Signals (.phi., .psi., z) of coordinate measuring devices are generated with the movement of the probe. Signals (u, v, w) of a transducer of the probe are generated with a deflection of the probe pin 11. Control signals (80 to 84) are generated from the first signals and/or the second signals and these control signals characterize the start and the end of the measuring operation on the geometric element and the validity of the coordinate measurement values (X, Y, Z).

Abstract: Auxiliary device for assisting in singling or separating sheets in an upper region of a sheet pile provided for single-sheet transport in a sheet transport direction within a sheet processing machine, a respective top sheet of the sheet pile being removable therefrom at a given time by at least one singling or separating device including at least one sheet trailing edge blasting or blowing device for feeding the sheet to the sheet processing machine, includes at least one feeler rod disposed at a location transverse to the sheet transport direction for measuring the height of the sheet pile, and respective fanning or loosening blowers disposed laterally of the sheet pile upstream of the feeler rod, as viewed in the sheet transport direction.

Abstract: A method of operating a torque transmitting system with a hydrodynamic power transmission and with a friction clutch, which constitutes a lock-up clutch and bridges the power transmission, involves controlling the lock-up clutch and the hydrodynamic power transmission so that clutch slip is present. The input torque furnished by a prime mover is divided into a torque which is to be transmitted by the power transmission and a torque which is to be transmitted by the lock-up clutch. The lock-up clutch includes an annular piston which is disposed between the cover and the turbine wheel of the power transmission. The radially outer portion of the piston constitutes a clutch disc and its radially inner portion is mounted on a complementary sealing hub. The power transmission is "soft" and exhibits a flat progress of the primary characteristic curve as well as a wide secondary characteristic curve, i.e., a wide torque conversion range.

Abstract: The invention is directed to a method for calibrating a coordinate measuring apparatus which has a probe 10. The probe 10 is movably guided in a plane (x, y) via two parallel pivot axes (6, 8) which are arranged one behind the other. For calibrating the primary dimensions (R1, R2, .phi.0, .psi.0, dT) of the coordinate measuring apparatus, contours or geometric elements are contact scanned on a calibration body with the probe. The contours or geometric elements are so selected that the diameter dT of the probe ball 12 attached to the probe enters into the measuring result for the geometric elements or their spacing with different weight or sign. Thereafter, the primary dimensions (R1, R2, .phi.0, .psi.0, dT) are determined from the measured values obtained by contact scanning the contours for the position of the probe 10 in the plane (x, y) and from the known dimensions of the geometric elements.

Abstract: 3,4-Epoxy-1-butene is prepared by the gas phase epoxidation of 1,3-butadiene by means of oxygen or oxygen-containing gases over silver-containing catalysts and isolation of the 3,4-epoxy-1-butene from the reaction exit mixture by performing the gas phase epoxidation in the presence of from 6 to 80 mol % of water vapor, based on the gas mixture supplied to the reactor.

Abstract: A silver catalyst containing one or more alkali metals and also tungsten as promotors for the direct oxidation of ethylene with oxygen to form ethylene oxide, on a porous support substantially consisting of .alpha.-aluminum oxide and having a specific surface area (BET) of from 0.3 to 3 m.sup.2 /g, which contains tungsten in a concentration of from 60 to 330 ppmwt, based on the total catalyst, per m.sup.2 of surface area for each gram of supporting material.

Abstract: A manually guided probe of a coordinate measuring device is mounted by two rotary shafts arranged one behind the other and a spring parallelogram for nearly reaction free movement in several spatial directions. The device has a workpiece table that is rotatable and tiltable about at least two shafts.

Abstract: A process for regenerating deactivated metal oxide catalysts comprising at least one of the elements antimony, iron, bismuth, molybdenum, vanadium, tungsten and/or uranium and a peptizable carrier, comprises the steps of:a) grinding the metal oxide catalyst in the presence of water to a particle size of from 10 nm to 10 .mu.m,b) heating the aqueous suspension of the metal oxide catalyst of stage a) to 30-100.degree. C. and adding an acid which peptizes the carrier,c) spray drying the acidic suspension of the metal oxide catalyst,d) heating the fluidizable metal oxide catalyst particles of stage c) to 500.degree.-850.degree. C.

Abstract: A catalyst for decomposing dinitrogen monoxide which is pure or present in gas mixtures comprises metallic silver applied to an alumina carrier with a BET surface area of from 5 to 25 m.sup.2 /g.

Abstract: A process for the catalytic gas-phase oxidation of acrolein to acrylic acid in a fixed-bed reactor with contacting tubes, at elevated temperature on catalytically active oxides with a conversion of acrolein for a single pass of .gtoreq.95%, wherein the reaction temperature in the flow direction along the contacting tubes in a first reaction zone before the starting reaction gases containing the reactants enter the contacting tubes is from 260.degree. to 300.degree. C. until an acrolein conversion of from 20 to 40% is reached, and the reaction temperature is subsequently reduced by a total of from 5.degree. to 40.degree. C., abruptly or successively in steps or continuously along the contacting tubes until a methacrolein conversion of .gtoreq.95% has been reached, with the proviso that the reaction temperature in this secondary reaction zone is not lower than 240.degree. C.

Abstract: A process for the catalytic gas-phase oxidation of methacrolein to methacrylic acid in a fixed-bed reactor with contacting tubes, at elevated temperature on catalytically active oxides with a conversion of methacrolein for a single pass of from 40 to 95 mol%, wherein the reaction temperature in the flow direction along the contacting tubes in a first reaction zone from entry of the starting reaction gases containing the reactants into the contacting tubes is from 280 to 340.degree. C. until a methacrolein conversion of from 20 to 40% is reached, and the reaction temperature is subsequently reduced by a total of from 5.degree. to 40.degree. C., abruptly or successively in steps or continuously along the contacting tubes until a methacrolein conversion of from 45 to 95% has been reached, with the proviso that the reaction temperature in this second reaction zone is not lower than 260.degree. C.

Abstract: A coordinate-measuring machine has a vertical column which is linearly guided in one horizontal direction (x) and on which a measurement arm is guided for vertical displaceability. The linear movement (x) is produced by a carriage in which the column is mounted for rotational displacement about a vertical axis. A workpiece to be measured is mounted to a turntable. The construction provides a coordinate measuring machine having four axes, two linear and two rotational, and the machine is structurally compact in terms of the measurement volume which is achievable.

Abstract: The measurement volume A of a given coordinate-measuring machine is increased by a device which consists (i) of a support plate (15) which can be displaced on the surface of the machine table (1) into at least two defined positions and (ii) of a device (16a-c, 17a-c) for measuring the position of the support plate in these different positions. The workpiece to be measured is clamped on said support plate (15) and can then be measured, section by section.

Abstract: A coordinate measuring apparatus includes guides made of aluminum. Scales which are also made of aluminum are used to measure the position of the measuring slide movable on the guides. In a preferred embodiment, the scales are in the form of a reflection phase grating and are applied directly to the surface of the guide member. In addition, a temperature sensor is provided which measures the temperature of the guide member and of the scale divisions. A method of producing the scale divisions is also disclosed.

Abstract: Supported silver catalysts which contain one or more alkali metals are prepared in a two-stage process by doping a basic catalyst which contains silver in metallic form and may also contain lithium with the heavy alkali metal sodium, potassium, rubidium and/or cesium using an impregnating solution which contains the heavy alkali metal and one or more nitrates of the general formulaR.sup.+ NO.sub.3.sup.-wherein R.sup.+ is an ammonium, hydrazinium, C.sub.1 -C.sub.12 -monoalkylammonium, C.sub.2 -C.sub.12 -dialkylammonium, C.sub.3 -C.sub.12 -trialkylammonium or C.sub.4 -C.sub.12 -tetraalkylammonium cation.

Abstract: The invention is directed to a coordinate measuring apparatus which includes an elevation measuring device. The elevation measuring device is connected with a stationary granite table via one or several linkage arms for determining the planar coordinates. Transducers for detecting angular values or pull-out lengths are arranged with respect to the joints or pull-out members of the linkage arms from which these planar coordinates can be computed by a computer. A method of determining the coordinates is also disclosed.

Abstract: A probe head for coordinate-measuring instruments has a torsionally rigid, play-free and friction-free probe-suspension system which defines a three-dimensional coordinate system, wherein a probe pin is deflectable in all three directions in space. In order to be able to use the probe pin completely independent of its orientation, a separate taring device provides taring adjustment for each of the three coordinate axes in space. The taring device automatically sets the zero position of the suspension system in any orientation of the probe head, and for any change in orientation. In this connection, it is particularly advantageous to develop each taring device from two springs which are preloaded to act in opposition upon an element which is gravitationally deflected upon any change in probe-head orientation; to reach the zero position detected by an indicator, i.e., to effect the taring adjustment, provision is made for adjustment of the preload force of at least one of these springs.

Abstract: A probe head for a coordinate-measuring instrument has a torsionally rigid, play-free and friction-free probe-suspension system which defines a three-dimensional coordinate system wherein the work-contact pin of the probe is deflectable in all three directions in space. For each of the three coordinate directions, an incrementally operating displacement-measuring system is provided, and each such system is associated with a zero indicator for recognition of the zero position of the system. Upon initial contact of the probe with the object to be measured, a trigger pulse is produced via a sensor. A subsequent electronic system processes the different signals delivered by the probe head so that optional operation is available either as a switching probe head or as a measuring probe head.

Abstract: Two methods are disclosed for eliminating the influence of guidance errors on the precision of determining the position of guided machine parts as in a coordinate-measuring machine, whereby the resulting measurement may be provided with a correction which is dependent on the guidance error. In a first method of the invention, the relevant guidance errors of the machine are determined and approximated by correction functions which are stored in the computer of the machine; the stored correction functions are used for automatic correction of errors otherwise inherent in operation of the coordinate-measuring machine. In a second method of the invention, additional measuring devices are mounted to displaceable parts of the machine, and these devices respond to changes in offset distance from reference surfaces arranged parallel to applicable coordinate guides; these measurement devices provide continuous detection of guidance errors, throughout the measurement process.