Abstract: A description is given of a filling level measuring device operating with microwaves, having a housing and an insert composed of a dielectric, and of a process for producing the dielectric, in which the dielectric constant of the insert is adjustable and in which the insert has a high chemical resistance and a mechanical strength adequate for industrial applications. The dielectric is a composite material composed of a fluoroplastic, in particular polytetrafluoroethylene, and ceramic and is produced by mixing powdered ceramic and powdered fluoroplastic, drying the mixture, pressing the mixture and sintering the pressed mixture.

Abstract: The invention relates to a device for determining the filling level of a filling material in a container. The device has a signal-generating unit, which generates electromagnetic measuring signals, a transceiver unit, which emits the measuring signals via an antenna in the direction of the surface of the filling material and which receives the echo signals reflected at the surface of the filling material, the antenna comprising a waveguide which widens in the direction of emission into a cavity of a defined shape, and an evaluation unit which determines the filling level in the container from the propagation time of the measuring signals. At least one dielectric filling material is provided which at least partially fills up the waveguide, and which virtually completely fills up the widened cavity of the antenna.

Abstract: Level measuring instrument The invention specifies a level measuring instrument operating with microwaves which transmits highly focussed microwaves in the transmission direction during operation and has an antenna (9) with a low space requirement, having a microwave generator (13) for producing microwaves at frequencies of greater than 40 GHz, an antenna (9, 9a) which is powered by the microwave generator (13) and is used to transmit the microwaves in the direction of the filled product, an antenna (9, 9b) which is used to receive microwaves reflected at a filled product surface, and a reception and evaluation circuit (15) which ascertains a transit time for the microwaves and uses this to determine the present level.

Abstract: The invention relates to a device for determining the filling level of a filling material in a container, having a signal-generating unit, which generates electromagnetic measuring signals, having a transceiver unit (2), which emits the measuring signals via an antenna (1) in the direction of the surface of the filling material and which receives the echo signals reflected at the surface of the filling material, the antenna (1) comprising a waveguide (3) which widens in the direction of emission into a cavity (4) of a defined shape, and having an evaluation unit which determines the filling level in the container from the propagation time of the measuring signals.

Abstract: The invention is directed to a measuring device for measuring an industrial process variable with a predetermined maximum power consumption by the measuring device. More specifically, the invention relates to a measuring device for connection to a current loop, in particular a 4-20 ma current loop, or to a digital communication, comprising devices for regulating the measuring operation of the measuring device in adaptation to the predetermined power consumption, wherein the regulating devices regulate to power consumption by the measuring operation of the measuring device in such fashion that this power consumption is approximated to the predetermined power consumption without the predetermined power consumption being exceeded.

Abstract: This level measuring instrument which operates with microwaves, has a radiation characteristic with a pronounced forward lobe and can be used to transmit and/or receive microwaves with a large frequency bandwidth. A housing section is designed as a waveguide short-circuited at one side and one end by a rear wall, and is virtually completely filled with an insert made of a dielectric. An exciter element, projects into the housing section and is connected to a microwave source. An antenna adjoins the housing section, for transmitting and/or receiving microwaves. A gap is arranged in the insert between the exciter element and the antenna. The gap forms a filter which is essentially non-transparent to higher modes of the waveguide.

Abstract: A description is given of a filling level measuring device operating with microwaves, having a housing and an insert composed of a dielectric, and of a process for producing the dielectric, in which the dielectric constant of the insert is adjustable and in which the insert has a high chemical resistance and a mechanical strength adequate for industrial applications. The dielectric is a composite material composed of a fluoroplastic, in particular polytetrafluoroethylene, and ceramic and is produced by mixing powdered ceramic and powdered fluoroplastic, drying the mixture, pressing the mixture and sintering the pressed mixture.

Abstract: In order to excite Lamb waves in a plate or container wall, an IDT transducer (interdigital transducer) is employed. The IDT comprises a layer composed of piezoelectric material, and on one of whose surfaces two electrodes which engage in one another like fingers are applied. The IDT is acoustically coupled to the plate or container wall by means of the surface facing away from the electrodes. If a radio-frequency AC voltage is applied to the connections of the electrodes, then a thickness vibration is initiated in the piezoelectric layer. If the speed of propagation or speed of sound of the longitudinal waves which result in this thickness vibration in the piezoelectric layer is matched to the phase velocity with which a s0 mode Lamb wave propagates in the material of the plate or of the container wall then only s0 mode Lamb waves are initiated by the resonance effect in the plate or container wall, by virtue of the acoustic coupling between the piezoelectric layer and the plate or container wall.

Abstract: A description is given of a filling level measuring device operating with microwaves, having a housing and an insert composed of a dielectric, and of a process for producing the dielectric, in which the dielectric constant of the insert is adjustable and in which the insert has a high chemical resistance and a mechanical strength adequate for industrial applications. The dielectric is a composite material composed of a fluoroplastic, in particular polytetrafluoroethylene, and ceramic and is produced by mixing powdered ceramic and powdered fluoroplastic, drying the mixture, pressing the mixture and sintering the pressed mixture.

Abstract: An antenna for transmitting microwaves is provided, which radiates microwaves to be transmitted as far as possible uncorrupted into free space and operates in a low-loss manner, having a circular waveguide (13) short-circuited at the end on one side, in which circular waveguide a transmitting element (15, 33) for feeding in microwaves is arranged, a funnel-shaped horn (25) adjoining an open end of the circular waveguide (13), the radius of which horn increases in the direction facing away from the circular waveguide, and an insert (27) made of a dielectric, which insert has a first cylindrical section (29), which fills the circular waveguide (13), and which insert has a conical section (31), whose tip points in the direction facing away from the circular waveguide and whose base area has a diameter which is greater than a diameter of the cylindrical section (29).

Abstract: The invention is directed to a measuring device for measuring an industrial process variable with a predetermined maximum power consumption by the measuring device. More specifically, the invention relates to a measuring device for connection to a current loop, in particular a 4-20 ma current loop, or to a digital communication, comprising devices for regulating the measuring operation of the measuring device in adaptation to the predetermined power consumption, wherein the regulating devices regulate the power consumption by the measuring operation of the measuring device in such fashion that this power consumption is approximated to the predetermined power consumption without the predetermined power consumption being exceeded.

Abstract: In order to excite Lamb waves in a plate (8) or container wall (8), it is proposed that an IDT transducer (interdigital transducer), which is known per se and comprises a layer (1) composed of piezoelectric material, and on one of whose surfaces two electrodes (2, 3) which engage in one another like fingers are applied, be acoustically coupled to the plate (8) or container wall (8) by means of the surface facing away from the electrodes (2, 3). If a radio-frequency AC voltage is applied to the connections (6, 7) of the electrodes (2, 3), then a thickness vibration is initiated in the piezoelectric layer (1).

Abstract: This level measuring instrument which operates with microwaves, has a radiation characteristic with a pronounced forward lobe and can be used to transmit and/or receive microwaves with a large frequency bandwidth. A housing section is designed as a waveguide short-circuited at one side and one end by a rear wall, and is virtually completely filled with an insert made of a dielectric. An exciter element, projects into the housing section and is connected to a microwave source. An antenna adjoins the housing section, for transmitting and/or receiving microwaves. A gap is arranged in the insert between the exciter element and the antenna. The gap forms a filter which is essentially non-transparent to higher modes of the waveguide.