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: An antenna device in a radar-based level gauge mounted at an opening in a roof of a tank, the antenna device comprising at least one elongated radiating structure, which has a length that is substantially larger, preferably more than 3-5 times longer, than a maximum cross-sectional length dimension of the opening; is oriented in a non-vertical position; and is configured and fed to produce an essentially vertical radiation beam directed downwards in the tank. Preferably, the antenna device is foldable and is inserted into the tank through the opening and oriented in the non-vertical position by means of folding the radiating structure.

Abstract: A liquid level measuring gauging system including a radar antenna, a plurality of functionally independent radar measuring channels, and a feeder operably connected with the channels and operable to feed microwave signals of the channels to the antenna.

Abstract: A method for radar-based gauging of the level of a substance in a tank (13) having at least one interfering structure, e.g. a beam (16a); an agitator (16b) or a tank side wall (16c), comprises transmitting a microwave signal in a predetermined polarization state (LHCP) towards the surface (14) of the substance and the at least one interfering structure; detecting, separately in two different polarization states (LHCP, RHCP), microwave signals (32, 33, 34) as reflected against the surface of the substance and against the at least one interfering structure; distinguishing based on signal strengths of the microwave signals detected separately in the two different polarization states, the detected microwave signal (32), which has been reflected against the surface of the substance; and calculating based on a propagation time of the distinguished microwave signal the level of the substance in the tank.

Abstract: A method for radar-based gauging of the level of a substance in a tank (13) having at least one interfering structure (16a-c), comprises the steps of: (i) transmitting a microwave signal in a plurality of radiation lobes (15a-b; 15a-d), each of which being individually directed towards the substance and at least one of which being directed towards the interfering structure; (ii) for each of the radiation lobes detecting temporally resolved the microwave signal as reflected against the substance, and for at least one of the lobes detecting the microwave signal as reflected against the interfering structure; (iii) based on signal strengths of the detected microwave signals, distinguishing the detected microwave signals, which have been reflected against the substance; and (iv) based on a propagation time of at least one of the microwave signals distinguished as those, which have been reflected against the substance, calculating the level of the substance.

Abstract: The present invention relates to a circuit and method for generation of trigger signals for a radar level gauging systems. A pulse-width modulator, has an input connected to a pulse-repetition-frequency generating oscillator. A monostable multivibrator, has an input connected to an output of the pulse-width modulator. First and second integrators are connected to an output of the pulse-width modulator and the monostable multivibrator respectively. A voltage summation element, is connected to an output of the first and second integrators respectively and at least one control signal input. A servo regulator provides a control loop between an output of the voltage summation element and a control port of the pulse-width modulator. A reference clock output is provided at the output of the monostable multivibrator and a second clock output is provided at the output of the pulse-width modulator.

Abstract: Radar antenna (1) for the transmission and reception of radar waves (4) for measuring the level of a surface of a liquid enclosed in a tank, wherein the radar antenna (1) is arranged above the surface (3a) of the liquid and substantially directed downwards towards said surface and said level determined by evaluation of the time lapsed between the transmission and reception of a signal included in said radar waves and wherein said radar antenna (1) has a front surface (1a) for transmission and reception of said radar waves, wherein said antenna (1) is a planar antenna having a sheet arranged on the surface (1a) of the antenna, wherein said sheet has a sheet surface (1b) between said antenna front surface (1a) and the surface (3a) of the liquid and said sheet surface (1b) being arranged in a predetermined angle &agr; being greater than 0° in relation to the horizontal plane H, whereby a fluid occurring on the surface (1b) of the sheet is drained off by means of gravity.

Abstract: A radar level gauge for measuring a level of a surface of a product in a tank having a two-wire process control loop, output circuitry coupled to the two-wire process control loop for setting in the loop a desired value of a loop current (Iloop) corresponding to the product level, a power supply circuitry coupled to the two-wire process control loop for receiving power from the loop and being a source of power for a microwave source, a microwave receiver, a measurement circuitry and the output circuitry and including a converter for transferring power from the loop to said power supply circuitry by means of feeding a first current (IDC/DC) from the loop to the power supply circuitry, a current generator included in said output circuitry for generating in parallel to said first current a second current (Ish) in the loop for maintaining said loop current at a value corresponding to said product level and a sensing circuit for determining the value of said second current and having an output indicative of the va

Abstract: The present invention relates to a device in a level gauging system comprising an antenna using radar waves to gauge a level of a surface of a fluid kept in a container. The antenna is arranged above the fluid surface and comprises a plane surface facing the fluid surface and being substantially parallel with the fluid surface. The plane surface has means for transmitting radar waves towards the fluid surface and means for receiving reflected radar waves from the fluid surface in order to gauge the fluid level. The antenna comprises a radome which at least partially covers the plane surface and is shaped such that condensed fluid is directed away from the antenna by force of gravity. A thermally insulating filling material is provided between the radome and the plane surface.

Abstract: The invention relates to a method and a device for measuring a level in a receptacle using radar. Via an aerial (1) directed down into the receptacle, an electromagnetic wave is transmitted and a reflected and time-delayed wave is received, the level being calculated from the time delay. Via one and the same aerial (1) at least two waves are transmitted and received, which are mutually distinguishable by a detectable characteristic for each wave. The device according to the invention is characterized in that connected to the aerial (1) is at least one further radar measuring channel (3; 4), the radar waves of which are mutually distinguishable and distinguishable from the radar wave used in a first radar measuring channel.

Abstract: A horn antenna for transmitting microwaves. A conical horn includes a small opening and a large opening. A transition piece includes a tapering portion and a non-tapering portion. The transition piece is arranged in the conical horn between a waveguide and an environment that the horn antenna is arranged in. A transition between the tapering portion and the non-tapering portion is arranged between the small opening and the large opening of the conical horn. The non-tapering portion engages the small opening of the conical horn.

Abstract: A device for gauging the level of a fluid in a container includes a floating roof, a transmitter for feeding a first microwave signal downwards in the direction of a fluid surface of the fluid, and a receiver for receiving a reflected microwave signal. The device includes a collector located above and in the vicinity of the floating roof, collecting the first microwave signal producing a collected microwave signal. The device also includes a vertical wave guide passing through the floating roof. The vertical wave guide guides the collected microwave signal to the fluid surface, and receives a reflected microwave signal reflected from the fluid surface. The vertical wave guide then guides the reflected microwave signal back to the collector and further to the receiver. It is a special feature to permit accurate measurement of the level of the fluid surface without having direct access to the surface.

Abstract: A device for gauging the level of a fluid in a container is described. It comprises a transmitter for transmitting a polarizable microwave signal through a first waveguide section, a receiver for receiving a reflected microwave signal, an electronic unit for determining the reflex position of the reflected microwave signal and an antenna means with a second waveguide section. The device is primarily characterized in that the transmitter and receiver, respectively, transmits and receives a waveguide mode each, mutually orthogonal, and by an easily replaceable third waveguide section (6, 16, 17) inserted between the first (2) and second (5) waveguide sections, provided with means (12, 14, 15, 22) for polarization and/or damping for optimal adaptation of the device to various containers and antennae.