Danfoss A/s

Lindab Ab

Agena A/s

Flonidan A/s

Henning M Hansen

Frands W Voss

Konstantin Lassithiotakis

John Nyrup

Hans E Jacobsen

Henry Hansen

Hans Schmidt-Hansen

Allan S Pedersen

Mogens Bech Laursen

James Digby Collier

Karsten Westermann

Kristian Iversen

Niels H Gade

Bertel Birker

Niels Per Mondrup

Richard-Jan E Jansen

Roger F Sewell

Hans J&oslash;rgen Moos

Hans Jo Pedersen

A system or a method for measuring flow of fluid or gas, has a flow duct with at least two transducers which generate at least one beam of ultrasound in the flow duct in which ultrasound transducers are placed in a fixed positions in a duct for flowing air where the electronic device for analyzing signal from the transducers is performed in a handheld device. A transmitter circuit is permanently connected to the transducers and a receiver circuit is placed in a handheld device. The transmitter circuit has calibration data representing the actual placement of the transducers in relation to the actual duct, which calibration data is communicated by every connection to the receiver circuit. Hereby can be achieved that transducers can be permanently placed in ventilation ducts in buildings, where placement of ultrasound transducers for measurement and for calibration of measurement of an air stream is nearly impossible.

System for identifying a sensor and measuring flow in a flow duct

A system or a method for measuring flow in a flow duct has at least two ultra sound transducers. The flow of air in a duct is measured by one or more transducers transmitting beams of ultra sound controlled by a microcontroller based electronic system in which the microcontroller stores a vector of data samples for each direction of transmission, which vector includes an appropriate number of N samples forming a frame, the microcontroller multiplying each value of the frame which a complex number. Based on the result, the microcontroller calculates the flow in the duct. As a result, an efficient flow measurement of air flowing in a duct can be achieved.

System or a method for measuring flow of fluid or gas

In a circuit arrangement for deriving the measured variable from the signals (S to S ) of at least two sensors ( ) of a flow meter, which flow meter comprises one or several parallel fluid lines ( ) and means ( ) for exciting oscillations of a predetermined fundamental frequency (&ohgr;) in the fluid line(s), the sensors ( ) detect the oscillations and the sensor signals (S to S ) are supplied by way of a respective A-D converter ( ) to a digital processing unit (P) having a computation circuit ( ), in which their phase difference (&PHgr;) is determined as a measure of the flow. In order to be largely independent of unwanted changes in the fundamental frequency (&ohgr;) of the sensor signals (S , S ), and to measure the flow with little effort and with as few errors as possible, provision is made for the processing unit (P) between the A-D converter ( ) of each sensor signal (S , S ) and the computation circuit ( ) to comprise a digital multiplier circuit (M) and a digital filter arrangement (F) downstream thereof, for the digital sensor signals (S , S ) to be multiplied in the multiplier circuit (M) with respective digital signals (I, R) phase-displaced by 90&deg; with respect to one another that represent sinusoidal oscillations of identical maximum amplitude (x) and of a frequency (&ohgr;&plus;&Dgr;&ohgr;) that varies by a slight difference frequency (&Dgr;&ohgr;) from the fundamental frequency (&ohgr;), and for the pass band of the filter arrangement (F) to be matched to the difference frequency (&Dgr;&ohgr;).

Circuit arrangement for deriving the measured variable from the signals of sensors of a flow meter

A system for dispensing batches of fluid comprising a flowmeter ( ), a pump or valve ( ) for starting and stopping the flow and a controller ( ) for controlling the pump or the valve. In order to reach a target batch size, the settling time at start of the flowmeter is compensated for as well as for the time it takes to stop the flow by generating a stop signal before the target batch size is reached. Further, to compensate for variations in the actual flow caused by variations in the feed pressure and the like, the compensation is made a function of the actually measured flow. A controller or a batch flow meter for use in dispensing batches is equipped with an interface for setting a compensating time constant and a correction unit for compensation of changes in the flow. The correction unit can consist of a differentiator an a summation circuit. Using digital techniques, the correction unit can be made as a lead filter.

Batch dispensing system for fluids

A flowmeter and a method of determining the mass flow rate. The flowmeter has a first measuring tube and a second measuring tube which are arranged in a common housing and are connected to one another mechanically. Also provided are an excitation device for exciting the measuring tubes to oscillation, and a detector device for detecting oscillation parameters which is connected to an evaluating device, which determines a mass flow rate signal for each measuring tube from output signals from the detector device. The object is to improve the measuring accuracy in cases in which identical conditions do not prevail in the measuring tubes. For that purpose, an amplitude detecting device is provided which detects the amplitude of the oscillation of each measuring tube, and a correcting device is connected to the evaluating device, which correcting device has a flow input and an amplitude input for each measuring tube.

Flowmeter with first and second measuring tubes having correcting device for the measuring tubes, and method of determining mass flow rate

Mass flowmeter with bidirectionally wound oscillation detector

Isolated liner for an electromagnetic flowmeter

A mass flowmeter has a flow-through channel (2) and as its measuring section (10) a thin strip (3) which at one end has an oscillation generator generating waves travelling along the measuring section (10) and at the other end has an energy converter (8, 9) acting as oscillation detector for these travelling waves. An evaluating circuit (11) determines the mass flow on the basis of the travelling speeds which are different in and against the direction of flow (X). In particular, only one measuring section (10) is provided, the energy converters (8, 9) of which are operable alternately as oscillation generator and oscillation detector. In this manner, meters of relatively short length and high accuracy can be made.

Mass flowmeter

The flow meter works on the Coriolis principle and has a measuring tube and at least two energy converters. At least one of the energy converters is an oscillation exciter for oscillating the tube to generate a wave traveling along the tube and an oscillation detector. An evaluating circuit uses the speed of travel of waves in the direction of flow of fluid through the tube and in the direction opposite the direction of flow to determine the mass flow of fluid through the tube.

Mass flow meter working on the coriolis principle

The invention relates to a protective circuit for the induction coil of a magnetically inductive type flow meter. If the leads of a flow meter used in an explosive environment are cut there can occur a high voltage and resulting sparking which could cause an explosion. The invention provides a circuit in which a short circuit path is provided for the induction coil if the leads thereof are severed to prevent the development of a high voltage which could cause dangerous sparking.

Protective circuit for the induction coil of a magnetically inductive

The invention relates to a magnetically inductive flow meter which generates a combined signal made up of a coil generated alternating voltage and an alternating simulated voltage. An evaluating circuit processes the combined signal to determine a flow rate output value in a manner which minimizes the temperature and time drift influences on the components of the flow meter.

Magnetic inductive flow meter

In an electromagnetic flow meter having a ceramic measuring tube, a housing arrangement is provided which forms a fluid tight capsule surrounding the measuring tube to prevent the escape of fluid if the tube should happen to crack or break in the use thereof.

Electromagnetic flow meter

The invention relates to an electromagnetic flow meter of the type having a cylindrically shaped tube section with two magnetic poles each having a core section carrying a winding attached to the outside and on opposite sides of the tube section. Smaller dimensions and lower losses in the magnetic circuit are achieved by providing a casing or yoke unit formed of sheet metal members and having U-shaped core sections. The core sections have central webs adapted to the curvature of the pole shoes and rectangular coils are disposed respectively between the associated pole shoes and sheet metal yoke members.

The invention relates to an electromagnetic flow meter with a magnetic system having two magnetic poles which are attachable to a measuring tube from the outside, an outer yoke, and at least one separating gap. Each pole has a pole shoe and a core section carrying a winding which is connected at the radially outward end thereof without a gap to the adjoining magnetic system portion and the separating gap is disposed beyond the magnetic path for the stray flux.

Growing community of inventors

Nordborg, Denmark

Henning M Hansen