Abstract: A radar level gauge system for gauging the level of a filling material in a container is disclosed. The system comprises a waveguide extending towards the surface of said filling material; a transmitter for transmitting a microwave signal of a first mode of propagation in the waveguide; and a receiver for receiving the microwave signal reflected against the surface of the filling material and propagating back through the waveguide. Further, it comprises a processing circuitry for determining the filling level of the container based on the reflected microwave signal; and a transition element connecting the waveguide and the transmitter, wherein the transition element is configured to allow a part of the transmitted microwave signal to leak into a second mode of propagation.

Abstract: A pulsed radar level gauge, comprising a transmitter for generating and transmitting a signal in the form of a pulse train, means for receiving pulses reflected in said tank, and to form an analogue tank signal based on these reflections, an analogue to digital converter for sampling and digitizing said tank signal and forming a digital time domain reflectometry (TDR) signal, and means for varying the output power of said transmitter during the transmission of said pulse train, in order to adjust an amplitude of said analogue tank signal to match the dynamics of said A/D-converter. A gain function applied on the receiver side is thus replaced by varying the output power on the transmitter side. This allows the signal-to-noise ratio to be improved, as the noise will not be amplified together with the signal.

Abstract: The present invention relates to a radar level measuring device for non-contact measurement of a level of a product in a container. The device comprises a flange which is mounted on the container in such a way that a lead-through of the flange at least partly covers an opening in the container. The device further comprises a waveguide part, insertable into the flange. When inserted, the insertable waveguide part is arranged to come to a stop at a distance (D) from the surface of the flange intended to face the container, along which distance (D), a waveguide is formed, forming a continuous waveguide together with the insertable waveguide part when inserted.

Abstract: A method and a system for processing a reflected microwave signal generated by a radar level a gauge system arranged to transmit microwaves towards the material in the tank, and receive a reflection of said microwave signal as a tank signal. The tank signal is processes by a plurality of processes, each process being adapted to determine a process variable in a specific region of the tank, each specific region corresponding to a predefined propagation distance range. Such multi-processing of the received tank signal has the advantage that each process can be optimized to that particular region of the tank. More specifically, a process concerned with a particular region of tank only needs to treat a portion of the tank signal.

Abstract: An antenna in a radar level gauge for determining the level of the surface of a medium stored in a tank. The antenna has a first and a second electrically conductive layer, and between the conductive layers a dielectric layer. The second of the conductive layers is provided with a number of holes in a predetermined pattern. Leading to the center of the dielectric layer is a transmission line. The microwaves from a radar unit in the radar level gauge are supplied to the dielectric layer in the antenna via the transmission line and transmitted out in a radial direction from a feed point in the dielectric layer that acts as a waveguide. Via said holes in the second conductive layer a microwave beam radiates out. Due to matching of the phase of the microwave and the placing of the individual holes in the pattern that the holes form, a predominant waveguide mode of the desired order is obtained.

Abstract: A radar level gauge system is disclosed, comprising: a transmitter for transmitting pulsed measuring signals into a tank; a receiver for receiving echo signals from the tank; and processing circuitry for processing the received echo signals, said processing means including an amplifier for amplification of the received echo signals. Further, the amplifier is operable in a high and a low amplification mode, and the processing circuitry is arranged to control the amplifier intermittently in order to be in the high amplification mode only during certain time slots. By intermittently operating the amplifier in a low amplification mode, providing only a low or moderate amplification, or preferably being shut off (i.e. with essentially no amplification), the power required for the amplification could be significantly reduced. Further, the noise generated by the amplifier could be significantly reduced. A corresponding processing circuitry and operating method are also disclosed.

Abstract: The present invention relates to a radar level gauge (1) comprising an antenna (2), a tank sealing (3), an electronics unit (4) and a waveguide feed (5) between the electronics unit (4) and the antenna (2). The waveguide (5) is essentially straight and has a 90°-symmetric cross section and is further arranged to accommodate two essentially orthogonal waveguide modes. The waveguide (5) further has a length (I) below two times the range resolution of said radar level gauge (1). The present invention further relates to a method for improved radar level gauging using a radar level gauge (1) as above.

Abstract: A radar level gauge system for determining the filling level of a filling material in a tank is disclosed. The system comprises an antenna device for emitting measuring signals towards the surface of the filling material and a receiver device for receiving echo signals from the tank. Further, the system comprises processing circuitry for determining the filling level of the tank based on said echo signal, wherein said processing circuitry is adapted to amplify the received echo signals in dependence of the distance from which the echo signals originates, in such a way that an echo signal from a lower filling level is more amplified than an echo signal from a higher filling level. The processing circuitry is adjustable to optimize the amplification of the echo signal based on the height of the tank. A corresponding processing circuitry and method of operation is also disclosed.

Abstract: A method and a device for measuring, by means of radar, in an enclosed space (1) in which a liquid (2) is stored, the level of a liquid surface (6), where the method involves the steps: a radar unit (3) mounted on the roof (4) of the enclosed space transmits a microwave signal downwards into the enclosed space (1) through a waveguide (7) that communicates with the liquid in the enclosed space; the transmitted microwave signal's polarization alters according to a predetermined time sequence in such a way that the signal is propagated alternatively at least in a first and a second plane of polarization; the signal transmitted in the first plane of polarization is reflected by the liquid surface (6) back to the radar unit (3); the signal in the second plane of polarization is reflected by at least one reference transmitter placed at a known distance from the radar unit; a calculating unit calculates the level of the liquid surface based partly on the propagation time for the microwave signal, i.e.

Abstract: A method and a system for radar-based gauging of a filling level of a filling material is disclosed, wherein the tank has at least one interfering structure. The method comprises: transmitting at a first time moment a microwave signal towards the surface of the filling material; receiving microwave signals as reflected against the surface of the filling material and as reflected against said at least one interfering structure; calculating based on propagation times of the transmitted and reflected microwave signals at least two distances to reflective surfaces in the tank; and repeating at a second time moment the transmitting, the detecting and the calculating, wherein said first time moment is timely separated from said second time moment. Based on the several repeated measurements, the distance to the surface of the filling material is determiend as the calculated distance that exhibits the greatest change between said first and second time moments.

Abstract: A radar level gauge for measuring the level of a surface of a product stored in a tank by use of radar. The radar transmits microwaves towards the surface and receives microwaves reflected by the surface and is adapted to transmit and receive microwaves within two widely separated frequency bands. Widely separated frequency bands are chosen to utilize the differences in attenuation due to foam on the surface and the differences in beam-width or other disturbances. The ratio between the center frequencies of the two widely separated frequency bands can be quantified as at least greater than 1.5:1 or preferably greater than 2:1.

Abstract: An antenna device for determining the filling level of a filling material in a container (tank) is disclosed. The antenna device comprises an essentially flat array antenna with an emitting area for emitting measuring signals towards the surface of the filling material and means for holding the array antenna over an opening of the container and to be connected to the rim of said opening in at least two points of attachment. Further, it comprises a protective dielectric cover covering said emitting area, wherein said dielectric cover has an extension larger than said opening in order to extend over the rim of said opening. The antenna device provides several advantages, such as a very efficient sealing of the container opening, a very clean solution towards the container and a very effective protection of the array antenna.

Abstract: A radar level gauge system is disclosed, having a transmitter for transmitting measuring signals towards the surface of the filling material, a receiver for receiving echo signals from said surface and a fastening structure adapted to secure said transmitter and receiver in a measuring position on a feed-through structure located in an upper boundary of said container. Further, a sealing unit is arranged between said fastening structure and said feed-through, and adapted to provide a pressure seal between the inside and the outside of the container, and in addition, there is provided means for blocking electromagnetic energy, adapted to block net transfer of electromagnetic energy between the inside and the outside of the container through said sealing unit.

Abstract: A method, an arrangement and a radar level gauging system for preventing interference, which radar level gauging system comprises at least two radar level gauges arranged to measure a filling level of a product kept in a container. Microwave pulses are transmitted towards the surface of said product and microwave pulses reflected by said surface are received by said at least two radar level gauges. Information is provided with said microwave pulses and said information is used for controlling the measurement pulses of said at least two radar level gauges.

Abstract: A radar level gauge using microwaves coupable to a two-wire process control loop for measuring level of a product in a tank. A microwave antenna unit is directable into the tank. A low power microwave source sends a microwave signal through the antenna unit into the tank. A low power microwave receiver receives a reflected microwave signal from a surface of the product in the tank. Measurement circuitry coupled to the source and receiver initiates transmission of the microwave signal and for determining product level based upon the received signal. Output circuitry coupled to the two-wire process control loop transmits information related to product level over the loop. Power supply circuitry coupled to the two-wire process control loop receives power from the loop being the sole source of power for the low power microwave source, the low power microwave receiver, the measurement circuitry and the output circuitry in the radar level gauge.

Abstract: There is provided a radar level gauge using microwaves for measuring a level of a surface of a product in a tank, comprising an antenna for transmitting microwaves to the surface and receiving microwaves reflected by the surface, a measurement circuitry feeding said antenna through a hollow wave guide and said wave guide including at least an antenna wave guide member, at one end couplable to the antenna and at its other end having an opening in an intersection across the wave guide, wherein the radar level gauge further comprises: a dielectric barrier extending along said intersection across the opening of said antenna wave guide member for non-conductively separating said antenna wave guide member from the measurement circuitry, said dielectric barrier having a first side facing the wave guide in a direction towards the antenna wave guide member and said dielectric barrier having a second side facing a direction substantially away from said antenna wave guide member.

Abstract: Method and device for calculating the level of the surface of a product in a storage room by a radar level gauging system, which includes a first gauging device for calculating a first value of level and functionally separated from the first gauging device a second gauging device for calculating a second value of said level, wherein: a first signal is produced being dependent of a preset first threshold value of the level in the first gauging device, a first current level value signal is output from the first gauging device, a second signal is produced in dependence of a preset second threshold value of the level in the second gauging device, a second current level value signal is output from the second gauging device and the value of the current level of said surface is presented by an indicating unit adapted to receive at least one of the first level value signal and the second level value signal for evaluation of the current level value.

Abstract: An apparatus for gauging the level of a liquid, above which a gas having a dielectric constant within a predetermined dielectric constant range exists, comprises a transmitter for transmitting a microwave signal in a propagation mode in a tube through the gas towards the liquid surface; a receiver for receiving the microwave signal reflected against the liquid surface and propagating back through the tube; and a processing device for calculating from the propagation time of the transmitted and reflected microwave signal the level of the liquid. In order to essentially avoid the influence on the calculated level by the dielectric constant of the gas above the liquid, the transmitter is adapted to transmit the microwave signal in a frequency band, at which the group velocity of the microwave signal in the propagation mode in the tube is, within the predetermined dielectric constant range, essentially independent of the dielectric constant.

Abstract: The present invention relate to a horn antenna at a radar level gauge for determination of a level of a surface of a medium stored in a tank and a method of making a horn antenna which is mechanically constituted such that the horn antenna will withstand the environment of the tank interior. The antenna comprises a first conductive housing (7) having a wave guide port (8), which is connectable to a wave guide, a first aperture (10), which is separated from the wave guide port (8) and a fist divergent section between the wave guide port (8) and the first aperture (10). A dielectric body (11) is arranged inside and essentially filling the first conductive housing (7), which body (11) displays a free end (12) in the area of the first aperture (10).