Abstract: The resonance of a piezoelectric vibrating element itself sets the frequency of the excitation producing ac oscillator for e.g. Kelvin probe or chopper applications.The oscillation amplitude is continuously adjustable. The superposition of a dc voltage in addition to the ac excitation voltage renders a continuously adjustment of the mean spacing of the working electrodes. A phase stable reference signal is provided for phase sensitive amplifier synchronization.

Abstract: For certain related dimensions of features of a nozzle feeding a fluidized bed reactor from below, it has been found that a central flow of a coating gas is squeezed down in diameter in passing through a constriction at the nozzle end by the action of the surrounding dilution gas flow, without the setting up of turbulence such as might have been expected, which would cause deposits from the decomposition of the coating gas at the constriction. The spacing between the mouth of the central tube that feeds the coating gas and the constriction at the end of the nozzle should be in the range of 20 to 70 mm, the diameter of the constriction aperture should be in the range from 3 to 10 mm and the diameter of the central channel should be greater than the constriction aperture diameter but not more than 3.5 times the latter diameter. For coating particles having a density of about 10 g/m.sup.3 and a diameter of about 200 .mu.m , the constriction aperture diameter should not exceed 7 mm.

Abstract: A cold surface for cryogenic pumps in the form of a (filled/through-streamed) double wall which is acted upon by a liquid refrigeration medium, as well as to a process for the production of such a cold surface. The double wall is formed by a series of thin-walled narrow tubes which are interconnected with each other, to which there are presently attached thin axially parallel, good heat conductive metal lamellas, wherein the tube diameter, tube spacing and wall thickness, as well as the lamella thickness, with consideration being given to a minimization of the total mass of the surface, are so correlated and dimensioned with respect to each other that the temperature differences within the lamellas of the surface which is acted upon with liquid refrigeration medium at a maximum occuring heat loading will remain below 0.1.degree. K.

Abstract: A cell for photoacoustic spectroscopy has a metal heat conductive rod immersed at one end in a liquid coolant and another end forming part of the sample-receiving cell for accurate control of the temperature to eliminate thermal distortion of the measurements.

Abstract: A rotary measuring body for a gas-friction vacuum meter has its surface formed with a macroscopic roughness which provides a gas-friction coefficient minimally affected by the microscopic roughness of the surface. As a result, the output signal and sensitivity of the vacuum meter is high and is less susceptible to change as a result of surface corrosion.

Abstract: A voltammetric cell, particularly for the determination of trace elements in a liquid, such as water, comprises a cover in which the measuring electrode and a reference electrode are mounted and which sealingly engages the cell vessel so that the contents of the latter will be sealed from contamination by the environment during the measuring process. The exchangeable measuring electrode has an analysis cup or crucible within the vessel into which the electrode can be inserted the bottom of the vessel having a configuration complementary to the external configuration of the replaceable crucible or cup. The cup may have a downwardly tapering frustoconical configuration and the base of the vessel can have a corresponding downwardly tapering recess accommodating at least the bottom of the cup.

Abstract: Tubular or rod-shaped pieces of a metal having a holding-back capability, with respect to the principal atomic or molecular contaminant in a gas, are arranged in the interior of a containing cylinder through which the gas flows, so as to provide passages for gas flow along the surface of the filter material pieces, the latter being typically disposed with their long dimension parallel to the direction of gas flow. The particles first stick on the surface, then diffuse irreversibly into the metal. For a prescribed pressure loss through the filter, a maximum value is obtained for a quantity that is equal to the filter length in the direction of gas flow times the second Stanton number divided by the hydraulic diameter, the latter term being equal to four times the volume of the space in the cylinder not occupied by the filter material divided by the surface of the filter material in contact with the gas.

Abstract: A fluid-heating apparatus comprises a ceramic burner head formed with narrow passages which alternate with one another for fuel and a combustion sustaining medium such as air, the slit-like passages opening into a combustion chamber at which combustion of the fuel/air mixture occurs. Downstream of this combustion chamber is a ceramic recuperator likewise formed with slit-like passages, the hot combustion gases traversing some of these recuperator passages while the fluid medium to be heated is passed through others of these passages so that heat exchange is effected through the thin ceramic walls supporting the slit-like passages of the ceramic recuperator.

Abstract: A reduction of the voltage across the electrolysis cell in which hydrogen is produced in the sulfuric acid hybrid closed cycle process by use of an electrolysis cell having an intermediate chamber between the anode and cathode chamber through which a separate electrolyte is caused to flow, is obtainable under operation with the electrolytes in both the cathode and the anode chambers having a concentration of sulfuric acid by weight of about 50% or more. It is found that the undesired formation of hydrogen sulfide and of sulfur remains at a tolerable small level if the catholyte is continuously renewed. A low specific resistance cation membrane is preferably used between the cathode and intermediate chambers, as well as between the anode and intermediate chambers.

Abstract: The activation of a mass of metal granules capable of storing hydrogen with the formation of hydride in a pressure vessel, instead of having to be activated before use by repeated heating in a hydrogen atmosphere followed by cooling and evacuation before the next heating, is activated in the pressure vessel used for storage by first heating a small portion of the granulate to the necessary activation temperature and then allowing the heat developed by the activation of that portion to produce the activation of the remainder of the granulate. It is found that it thus possible to provide complete activation with only one heating step. The small portion that is first activated may be a part of the granulate that is of a different composition that is easier to activate, for example, LaNi.sub.5, which can be activated at room temperature, or iron-titanium alloys that are capable of activation under 100.degree. C.

Abstract: A fluidized bed furnace employed for depositing pyrolytic carbon or silicon carbide on nuclear fuel particles is supplied with an inert dilution gas and a decomposable coating gas. These are supplied by means of a gas injector having at least three pipes 4 for coating gas extending within a surrounding duct for a stream of dilution gas 6. This leads to a partition 2 at the base of the bed, having at least three apertures 3 for through passage of the gases.

Abstract: A dual-slope integrator is provided in the usual manner with input switches for a measured voltage and reference voltage and with a first counter having a count capacitor N.sub.1, in addition to the usual integrating resistor and integrator condenser in circuit with an integrating amplifier. The output of the latter is applied to a comparator and a clock-pulse generator produces the counting pulses. According to the invention, a second counter is provided with a capacitor N.sub.2 so that the two counters together have a capacity N.sub.1 .times.N.sub.2, the input switching circuit is keyed by the clock pulses, and a further amplifier of amplification N*.sub.2 is provided, the amplification factor N*.sub.2 being approximately equal to N.sub.2.

Abstract: Burners operating with combustion air as the combustion-sustaining gas and a fuel, generally a vaporizable liquid fuel, have at least one ceramic body formed with passages for these two fluids allowing heat exchange through the walls separating these passages. According to the invention, these walls are porous so that fuel in the fuel passage can traverse the wall into an adjoining air passage by evaporization on the surface. The combustion air can be heated by recuperative heat exchange from exhaust gases of the combustion chamber. Burner heads of this type can be paired in mirror-symmetrical relationship.

Abstract: A ceramic recuperator for the heating of combustion air, e.g. for an oil-fired burner or boiler, which prepares at least the air in the formation of a fuel-air mixture which is ignitable at the burner. According to the invention the recuperator is provided with means, especially electrically operated for heating the ceramic body so that the initial combustion air can be heated before firing of the burner and the further heating of the recuperator by combustion products.

Abstract: A burner head of ceramic materials through which the fuel (combustible) and the oxidizing agent (oxygen or oxygen-containing gas such as air) are passed from an inlet side to an outlet side, combustion being effected at the outlet side. According to the invention, the gas passages for the fuel and the oxidizing medium are of elongated cross section and parallel to one another, being offset in pairs so that indirect heat exchange is effected between the two mediums through the separating ceramic wall. The passages can be formed as rectangular-section channels which are closed at the top and bottom by ceramic plates.

Abstract: A cold surface, (e.g. for use in a so-called cryopump, i.e. a cryogenic vacuum vapor pump), is formed by a reservoir for liquid hydrogen surrounded by a double-wall vessel over an intervening evacuated insulating space. The lowest points of the compartment formed between the walls of the double-wall vessel and the interior of the liquid helium reservoir are connected by a conduit provided with a valve.

Abstract: A filter for the removal by the exchange effect of fission products from the coolant, generally helium, of a nuclear reactor comprises a gas-tight duct containing at least one coil of corrugated metal strip, the coil being formed from two strip layers whose corrugations are mutually crossing.

Abstract: A cleansing apparatus for test-vessels such as cuvettes or the like comprising a support shaft and three spaced paralleled disks, two of said disks being secured to the shaft and the third disk being rotatably positioned on the shaft, a nozzle secured to the first disk, the second and third disks having apertures thereon for receiving cuvettes, so that a cuvette may be positioned over the nozzle through the apertures in one of the disks, and retained by the rotatable disk so that immersion of the apparatus into a cleansing solution forces a jet of solution through the nozzle for cleansing the cuvette.

Abstract: The reaction gas throughout of the supply duct feeding gas to the bottom of a fluidized bed reactor of the kind shown in U.S. Pat. No. 4,153,004, issued May 8, 1979, is increased by providing the reaction gas supply tube in the form of a bundle of tubes of small cross-section of about 2 mm diameter. Subdivision of the supply tube into hexagonal ducts in honeycomb arrangement maximizes the useful cross-sectional area of the supply tube. With the smaller elemental tube diameters, a higher rate of flow is maintainable without loss of laminar flow behavior, which behavior is maintained in the jet issuing from the subdivided reaction gas supply duct as it flows towards the constricted entrance into the fluidized bed container while being surrounded by a sheath of inert carrier gas supplied by an annular duct surrounding the reaction gas tube.

Abstract: A double-wall vessel has its inner walls spaced from the outer wall by a plurality of insulating spacers, each of which includes a thread stud affixed to one of the walls and reaching toward the other, the length of the stud being greater than the spacing tolerance of the vessel. On each thread stud is screwed a support body of thermally insulating material and arranged such that, wherein the body is screwed fully onto its stud, its maximum distance from the wall on which the stud is mounted is not greater than the minimum spacing between the two walls.