Showing papers by "ABB Ltd published in 1996"

A susceptor for a device for epitaxially growing objects and such a device

Abstract: A susceptor for a device for epitaxially growing objects of one of: a) SiC; b) a Group 3B-nitride; and c) alloys thereof on a substrate to be received in the susceptor has a channel (1) adapted to receive said substrate and through which a source material for the growth is intended to be fed. The walls (11-14) of the susceptor surrounding said channel are made of a material which may be heated by induction created by heating means intended to surround the susceptor. The susceptor is made of at least two separate susceptor wall pieces (11-14), and it comprises means (15) for securing said wall pieces of the susceptor to each other for forming the susceptor.

SiC semiconductor device comprising a pn junction with a voltage absorbing edge

Abstract: A semiconductor component, which comprises a pn junction, where both the p-conducting and the n-conducting layers of the pn junction constitute doped silicon carbide layers and where the edge of at least one of the conducting layers of the pn junction, exhibits a stepwise or uniformly decreasing total charge or effective surface charge density from the initial value at the defined working junction to a zero or almost zero total charge at the outermost edge of the junction following a radial direction from the central part of the junction towards the outermost edge.

Mixing ducts for a gas-turbine annular combustion chamber

Abstract: In a gas-turbine annular combustion chamber (4) which is arranged downstream of a compressor (1) and is equipped on its front plate with at least one row of premix burners (5) arranged in an annular form, in each case a combustion-air duct (15) designed as a diffuser leads directly downstream of the compressor outlet from the guide vanes (9) of the last compressor row to each burner (5), at the downstream end of which combustion-air duct (15) at least one longitudinal-vortex generator (16) is located, at least one fuel injection means (17) being provided in or downstream of the longitudinal-vortex generator (16). A mixing duct (19) which ends in the combustion chamber (4) and has a constant height (H) and a length (L) which corresponds approximately to twice the value of the hydraulic duct diameter (D) is arranged downstream of the fuel injection means (17). The overall size of the gas turbine in the region of the combustion chamber (4) can thereby be substantially reduced. In addition, the pressure loss between compressor outlet and turbine inlet is reduced.

Compressor with intercooling

Abstract: A gas turbine has a mainly axial-flow two-stage compressor (1A,1B), with an intercooler (5). It also has at least one combustion chamber (7,8), one or more turbines (2A,2B), and a recuperator (6) in which the compressor air is heated to the inlet temperature in the combustion chamber (7). At least a first compressor component (1A) has water injectors (12), and the intercooler has equipment for water recuperation (13). The latter is connected to the injectors via a delivery pump (14). The injectors may be arranged in the compressor in the plane of the stator blades, and may also be arranged over the entire height of the compressor duct.

Burner for a heat generator

Abstract: A mixer section (22), downstream from the swirl generator (100a), has transfer ducts (201) inside a first section (200) running in the direction of the current, they are used for transferring a current (40) formed in the swirl generator into a pipe (20) situated after the transfer ducts. A nozzle (103) injects the fuel and is displaced in relation to the start of the swirl generator by a section (126). The number of transfer ducts in the mixer section matches the number of part currents formed by the swirl generator. The outlet plane of the pipe has a break edge (A) for stabilising and enlarging the reverse zone (50) formed downstream.

A device and a method for epitaxially growing objects by cvd

Abstract: A device for epitaxially growing objects of SiC, a group III-nitride or alloys thereof by Chemical Vapour Deposition on a substrate (13) comprises a susceptor (7) having circumferential walls (8) surrounding a room (18) for receiving a substrate and means (11) for heating said circumferential susceptor walls and by that the substrate and a gas mixture fed to the substrate for the growth by feeding means (5). The heating means (11) is arranged to heat the susceptor (7) and by that the substrate (13, 13') above a temperature level from which sublimation of the material grown starts to increase considerably, and the feeding means is arranged to feed said gas mixture with such a composition and at such a rate into the susceptor that a positive growth takes place.

Device for damping thermoacoustic pressure vibrations

Abstract: A device for damping thermoacoustic pressure vibrations in a combustion chamber (1), in particular in the combustion chamber of a gas turbine, includes a pressure sensor (6) which is connected to the input of a regulating device (10), the regulating device (10) is connected at its output to a device for electrically controlling the flame in the combustion chamber (1). This device for electrically controlling the flame includes a voltage source (11) and an electrode (14). The electrode (14) is connected to a heat shield (12) which surrounds the outflow side of a burner (3) in an annular manner.

Protective circuit for series-connected power semiconductors

Abstract: An overvoltage protection device (SK) of a transient protection type in a series-connection of an arbitrary number of power semiconductors (T1, D1), intended to reduce the risk of overvoltage across a power semiconductor in a chain (P1,...PN) of series-connected power semiconductors (T1, D1), wherein the overvoltage protection device (SK) comprises at least one capacitor (C) and wherein the overvoltage protection device (SK) is activated when the voltage across the power semiconductor (T1, D1) exceeds the specified voltage level (Vprot), whereby the task of said capacitor (C) is to limit the voltage derivative (dVCE/dt) across the power semiconductor when the voltage across the power semiconductor exceeds the specified voltage level (Vprot). The overvoltage protection device limits too high a voltage growth across individual power semiconductors in the chain.

Method and apparatus for the wet cleaning of the nozzle ring of an exhaust-gas turbocharger turbine

Abstract: A method for wet cleaning of the nozzle rings of exhaust-gas turbocharger turbines is based on thermal shock of the contaminants, and includes the steps of injecting water in repeated, relatively small amounts, into the exhaust duct immediately upstream of the nozzle ring. A delay between injections allows the nozzle ring to reheat to operating temperature so that each water injection causes a thermal shock. An apparatus to perform the method includes water injection nozzles installed in the exhaust gas casing and a control system. The method and apparatus provide improved cleaning using less water than in known methods.

Monitoring of internal partial discharges on a power transformer

Abstract: In a method for monitoring of partial discharges in an electric power transformer (1) under normal operating conditions, the magnetic field at a high-voltage bushing (2) on the power transformer is sensed with an inductive sensor (6) comprising at least one coil (6a, 6b) arranged at the bushing, and the electric field at the bushing is sensed with a capacitive sensor (5). The output signals from said sensors are supplied to a signal processing unit (3) in which each one of the output signals is filtered in a separate bandpass filter (101, 102), whereupon the filtered output signals from said sensors are multiplied by each other. An output signal (PDI) from the signal processing unit is formed in dependence on the result of said multiplication for the purpose of detecting internal partial discharges in the transformer.

A METHOD FOR INTRODUCTION OF AN IMPURITY DOPANT IN SiC, A SEMICONDUCTOR DEVICE FORMED BY THE METHOD AND A USE OF A HIGHLY DOPED AMORPHOUS LAYER AS A SOURCE FOR DOPANT DIFFUSION INTO SiC

Abstract: A method for introduction of an impurity dopant into a semiconductor layer (2) of SiC comprises a step (a) of ion implantation of said dopant in said semiconductor layer at a low temperature The ion implantation is carried out in such a way that a doped and amorphous near surface layer (6) is formed, and the implantation step is followed by a step of annealing said semiconductor layer at such a high temperature that said dopant diffuses into the non-implanted sub-layer (3) of said semiconductor layer following said near surface layer

The remuneration of CEOs and corporate financial performance in Norway

Abstract: Economics and management literatures advocate that senior company executives should be remunerated on the basis of the financial performance of the firms they manage. This helps align the interests of management with those of stockholders. There are, however, problems in implementing pay for performance schemes and these, along with other factors, may lead to there being no empirical relationship between compensation and stockholder returns. This study set out to explore the determinants of chief executive compensation in Norwegian stock exchange listed firms. To date there have been very few studies on this topic using data from Norway; most previous research has employed American data. The results show a positive relationship between CEO pay and corporate size but there was no significant association between remuneration and corporate financial performance as measured by accounting profitability and as measured by stock returns. Estimates of the value added by companies were significantly related to chief executive pay. There was also a positive and significant relationship between a CEO's compensation and the average wage level of the company. This association may be due to the unique characteristics of Norway's social and economic structure.

Method for producing a semiconductor device having a semiconductor layer of SiC by implanting

Abstract: A method for producing a semiconductor device comprises a step of implanting first conductivity type impurity dopants of at least two different elements in a semiconductor layer being doped according to a second opposite conductivity type, and after that anneal the semiconductor layer at such a high temperature that one of said elements is diffusing slowly into the semiconductor layer and the other is diffusing rapidly thereinto.

A device for sensing of electric discharges in a test object

Abstract: A device for sensing electric discharges in a test object (1) with at least two electric connection conductors (1a, 1b, 1c, 1d) comprises transducer equipment and evaluation equipment (PA, ABU, LU). The transducer equipment comprises at least one transducer (6a, 6b, 6c, 6d) for direction-sensitive sensing of current pulses through the connection conductors by sensing a magnetic field, generated by the current pulses, and the polarity thereof. The transducer delivers a transducer signal (v1', v2', v3', v4', v11', v21') to the evaluation equipment in dependence on said current pulses and their direction. The evaluation equipment generates, in dependence on received transducer signals, an indicating signal (IND) indicating an electric discharge in the test object.

Airblast atomizer nozzle

Abstract: In an airblast atomizer nozzle (2) for the operation of a burner (1) operated with liquid and gaseous fuels (4, 6) the intermediate wall (18) between the inner (14) and outer (13) air duct is held via inner and outer support elements (21) which have a sliding fit (28) and which can be designed as swirl vanes. The atomizer edges (19) of the airblast nozzle (2) are angled in the direction of the nozzle axis (11). The nozzle is distinguished by small dimensions, a low pressure loss and a negligible tendency to coking.

METHOD FOR PRODUCING A SEMICONDUCTOR DEVICE HAVING A SEMICONDUCTOR LAYER OF SiC

Abstract: A method for producing a semiconductor device having a semiconductor layer (1-3) of SiC comprising a step of supplying dopants to the surface of the SiC layer during heating thereof for diffusion of said dopants into the SiC layer, and at least a portion of the surface layer of the SiC layer is prior to said supplying of dopants highly doped so as to control the tendency of the dopants to diffuse into the SiC layer under said surface layer portion.

Device and method for injecting fuels into compressed gaseous media

Abstract: A device for injecting fuels (4) into compressed gaseous media essentially comprises a cylindrical hollow body (24) with at least one fuel feed passage (2) and means for the introduction of compressed atomization air (5). A swirl chamber (1) is arranged in the interior of the hollow body (24), this swirl chamber being connected via at least one inlet opening (6) to the fuel feed passage (2). The cross-section of the swirl chamber (1) narrows in the direction of flow of the atomization air passed through the interior of the hollow body (24), thereby forming a cone (8). A dividing wall (20), which extends downstream at least as far as the center of the inlet openings (6), is arranged upstream of the swirl chamber (1), between the fuel in the swirl chamber (1) and the atomization air (5). A method for operating the device is furthermore described.

Method of operating a gas turbine on reformed fuel

Abstract: In a method for the operation of a power station installation which essentially comprises a compressor (4), a combustion unit and a turbine (12), the combustion unit comprising a conditioning stage for at least part of the combustion air and a combustion chamber, a portion (13a) of the compressed air (13) from the compressor (4) is passed through the conditioning stage and there first of all mixed with a quantity of fuel (14a). This mixture then passes into a generator (8), in which at least hydrogen is fractionated, this hydrogen then being used in the combustion chamber. The combustion chamber comprises a start-up burner (1), a catalytic stage (2) and a downstream second combustion stage (3). Both the air/fuel mixture (16a) fractionated in the generator (8) and the further compressor air (13) enter the combustion chamber, in which interdependent combustion occurs between the combustion units acting there, relative to the running up of the installation, for the purpose of minimizing pollutant emissions. (FIG. 1)

Gas insulated switchgear with grounding and disconnecting switches

Abstract: A switching apparatus includes a grounded, insulating gas-filled housing, the housing having a housing wall, and a power circuit-breaker disposed in the housing. The apparatus further includes a current connection for a first busbar, a current connection for a second busbar, and a current connection for a load outgoer. The apparatus further includes a grounding switch disposed in the housing, the grounding switch being connected between the power circuit-breaker and the current connection for the load outgoer, and a busbar disconnector, the busbar disconnector being connected between the current connection of the first busbar and the power circuit-breaker and between the current connection of the second busbar and the power circuit-breaker. An outwardly extended, first tubular flange arrangement is attached over a first opening in the housing wall, and an outwardly extended, second tubular flange arrangement is attached over a second opening in the housing wall. A first outdoor bushing is provided, the first outdoor bushing being fastened to the first tubular flange attachment, the current connection for the first busbar extending through the first outdoor bushing. A second outdoor bushing is provided, the second outdoor bushing being fastened to the second tubular flange attachment, the current connection for the second busbar extending through the second outdoor bushing. The busbar disconnector is movable between at least three positions, the busbar disconnector having a first and a second fixed contact and a movable contact arrangement, the movable contact arrangement interacting with the first and second fixed contacts and being electrically conductively connected to the power circuit-breaker, the first fixed contact defining an end of the current connection of the first busbar and being disposed in the housing, and the second fixed contact defining an end of the current connection of the second busbar and being disposed in the housing.

Method of operating gas turbine power plant with intercooler

Abstract: In a method of operating a combined-cycle plant which is based on a gas-turbine group, the compressor unit of this same gas-turbine group is equipped with an intercooler (9) By detecting parameters which comprise at least the ambient temperature (T), the air humidity (φ) of intake air (7) and the outlet pressure (Pic) of the intercooler (9), and by feeding the same to a computer (15), regulation is initiated by the latter, which regulation acts on members (17, 18) in the coolant circuit (13, 13a) between the intercooler (9) and a heat sink (14) The dew-point temperature of the cooled air (10), compressed to an intermediate pressure, downstream of the intercooler (9) is thereby influenced

Combustion chamber with two-stage combustion

Abstract: A combustion chamber with two-stage combustion has primary burners (110) of the premix type of construction, in which the fuel injected via nozzles (117) is intensively mixed with the combustion air inside a premix space (115) prior to ignition. The primary burners are of flame-stabilizing design, i.e. they are designed without a mechanical flame retention baffle. They are provided with tangential inflow of the combustion air into the premix space (115). Arranged downstream of a precombustion chamber (61) are secondary burners (150) which are designed as premix burners which do not operate by themselves.

Method for producing a semiconductor device having a semiconductor layer of SiC comprising a masking step

Abstract: A method for producing a semiconductor device having a semiconductor layer (1-3) of SiC comprises at least the steps of: a) appliction of a mask (4) on at least a portion of said SiC layer and b) a heat treatment of said SiC layer. The mask (4) is made of a material having crystalline AIN as only component or AIN as a major component of a crystalline alloy constituting said material.

Process for applying a metallic adhesion layer for ceramic thermal barrier coatings to metallic components

Abstract: In a process for applying a metallic adhesion layer for thermally sprayed ceramic thermal barrier coatings to metallic components, the surface which is to be coated being cleaned in a first process step, so that the metallic surface is free of grease and oxide, a binder is applied to the metallic surface of the base material in a second process step. Metallic adhesive powder is applied uniformly to the binder in a third process step and solder powder, which has a smaller particle size than the adhesive powder, is applied uniformly to the binder in a fourth process step. After drying the binder, a heat treatment is carried out for the purpose of soldering. The adhesion layers produced in this way are rough and provide a considerable positive lock for the ceramic thermal barrier coatings which are to be sprayed thereon.

Converter circuit, circuitry having at least one switching device and circuit module

Abstract: A converter circuit has at least one switching device (5, 6) and a diode (7, 8) arranged to be conducting when the device is turned off and reverse biased when the device is turned on. Said diode is made of SiC.

Semiconductor light emitting device

Abstract: A semiconductor light-emitting device employs a quantum well having a fundamental wavelength in the absence of an external electric field; a microcavity with two reflectors, having a resonance wavelength which closely corresponds to the fundamental wavelength of the quantum well; and electrodes for applying an electric field across the microcavity to change the wavelength of the quantum well and thereby control the radiance of the microcavity.

Method of operating a reheat power plant with steam injection

Abstract: In a method of operating a power station plant which essentially comprises a gas-turbine group and a waste-heat steam generator (14) arranged downstream, the exhaust gases from said gas-turbine group, which essentially comprises a compressor (1),tcw a first combustion chamber (4), a first turbine (7), a second combustion chamber (9), a second turbine (12) and a generator (19), are directed through said waste-heat steam generator (14). The superheated steam (15) arising there is injected at a suitable point into the gas-turbine group. The saturated steam (16) arising there flows via a heat exchanger (17) through which a portion of compressor air (18) flows. The saturated steam (16) is converted into superheated steam (25) which is subsequently likewise injected into the gas-turbine group. The measures increase the efficiency and multiply the specific output of the plant.

New low-voltage varistor composites

Abstract: New varistor-type polymer composites for low-voltage application have been developed. The filler is made of commercially available doped ZnO-varistor powder. The polycrystalline filler particles act as varistors due to their typical grain-boundary structure. The presented varistor composite materials show very low values for the breakdown field strength down to 200 V mm−1, as compared with already existing varistor-type composites, and fairly highα-values in the range of 10.

A device for heat treatment of objects and a method for producing a susceptor

Abstract: A device for heat treatment of objects (11) comprises a susceptor (7) adapted to receive an object and means (9) for heating the susceptor and thereby said object. The susceptor comprises an inner (17) and an outer (18) circumferential wall forming a closed space (19) therebetween and the inner of which defines a room (13) for receiving said object. Said space (19) is filled with a powder.

Combustion chamber with two-stage combustion

Abstract: The combustion chamber comprises at least one primary burner (110) of pre-mixture design. Fuel is intensively mixed with combustion air prior to ignition by sprays (117) which spray fuel into the inside of the pre-mixing chamber (130). The primary burners are formed to be flame stabilising without mechanical flame holders. The primary burner is equipped with tangential in-flows of combustion air into the pre-mixing chamber. A secondary burner (150) is provided downstream from the pre-combustion chamber (61). The secondary burner is formed so as not to be self operating.

Monocrystalline nickel-base superalloy with Ti, Ta, and Hf carbides

Abstract: A nickel-base superalloy, in particular for the fabrication of large monocrystalline components, essentially comprises (measured in wt %): 6.0-6.8% of Cr, 8.0-10.0% of Co, 0.5-0.7% of Mo, 6.2-6.6% of W, 2.7-3.2% of Re, 5.4-5.8% of Al, 0.6-1.2% of Ti, 6.3-7.0% of Ta, 0.15-0.3% of Hf, 0.02-0.04% of C, 40-100 ppm of B. 15-50 ppm of Mg, the remainder being nickel with impurities. Carbides of Ta, Ti, and Hf, and Mg, and/or Mg--O--S compounds are concentrated along small angle grain boundaries of the superalloy.