Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A mass flow measuring apparatus (1) is described, having tube (2), which at a first position (P1) is coupled as regards oscillation to a first energy converter (4) and at a second position (P2) is coupled as regards oscillation to a second energy converter (5), and having an evaluating device, the first and the second position (P1, P2) being spaced (L) from one another, the energy converters (4, 5) each being operable as oscillation generator and oscillation detector and the energy converters (4, 5) working alternately as oscillation generators. A method can therefore be carried out in which the tube (2) is caused to oscillate alternately at the first position (P1) and at the second position (P2), signals being measured at the second and the first position (P2, P1). It is desirable to be able to achieve accurate measurements even in the case of a measuring apparatus of small construction.

Abstract: In a circuit arrangement for deriving the measured variable from the signals (S1 to S2) of at least two sensors (23, 24) of a flow meter, which flow meter comprises one or several parallel fluid lines (20, 21) and means (22) for exciting oscillations of a predetermined fundamental frequency (&ohgr;) in the fluid line(s), the sensors (23, 24) detect the oscillations and the sensor signals (S1 to S2) are supplied by way of a respective A-D converter (36; 37) to a digital processing unit (P) having a computation circuit (46), in which their phase difference (&PHgr;) is determined as a measure of the flow.

Abstract: A mass flow measuring apparatus (1) is described, having tube (2), which at a first position (P1) is coupled as regards oscillation to a first energy converter (4) and at a second position (P2) is coupled as regards oscillation to a second energy converter (5), and having an evaluating device, the first and the second position (P1, P2) being spaced (L) from one another , the energy converters (4, 5) each being operable as oscillation generator and oscillation detector and the energy converters (4, 5) working alternately as oscillation generators. A method can therefore be carried out in which the tube (2) is caused to oscillate alternately at the first position (P1) and at the second position (P2), signals being measured at the second and the first position (P2, P2).

Abstract: In a circuit arrangement for deriving the measured variable from the signals (S1 to S2) of at least two sensors (23, 24) of a flow meter, which flow meter comprises one or several parallel fluid lines (20, 21) and means (22) for exciting oscillations of a predetermined fundamental frequency (&OHgr;) in the fluid line(s), the sensors (23, 24) detect the oscillations and the sensor signals (S1 to S2) are supplied by way of a respective A-D converter (36; 37) to a digital processing unit (P) having a computation circuit (46), in which their phase difference (&phgr;) is determined as a measure of the flow.

Abstract: A system for dispensing batches of fluid comprising a flowmeter (5), a pump or valve (6) for starting and stopping the flow and a controller (9) 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.

Abstract: A system for dispensing batches of fluid comprising a flowmeter (5), a pump or valve (6) for starting and stopping the flow and a controller (9) 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.

Abstract: 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.

Abstract: A system for dispensing batches of fluid comprising a flowmeter (5), a pump or valve (6) for starting and stopping the flow and a controller (9) 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.

Abstract: A system for dispensing batches of fluid comprising a flowmeter (5), a pump or valve (6) for starting and stopping the flow and a controller (9) 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.

Abstract: The invention concerns a mass flowmeter for measurement of the mass and the density of a fluid flowing through a measuring pipe. The mass flowmeter uses the Coriolis principle for establishing mass and density. The mass flowmeter comprises at least one, preferably two, measuring pipes. Each measuring pipe is provided with an oscillation generator and a first oscillation detector and a second oscillation detector. The oscillation generator is meant for making the measuring pipes oscillate, and the oscillation detectors are meant for detecting oscillations in the measuring pipes when fluid flows through the measuring pipes. The oscillation detectors consist of armatures in the form of bar magnets extending into a ring coil. The coil is provided with a first winding and a second winding which are connected in series, and which are arranged at a distance from one another along a longitudinal axis.

Abstract: A measuring section for an electromagnetic flowmeter is provided having a metallic measuring tube made of a non-magnetic material, a set of magnetic coils for generating a magnetic field in a direction substantially at fight angles to the direction of flow, an electrode arrangement which is arranged substantially at fight angles to the direction of the magnetic field and substantially at right angles to the direction of flow, and an electrical insulator on the inside of the measuring tube, and also a method for the manufacture of this measuring section. Here, it is desirable for manufacture to be carried out with a relatively high degree of reliability. For that purpose, the insulator is constituted by a surface layer of metal oxide or metal nitride having a thickness of more than 10 .mu.m an on the inside of the measuring tube. The inside of the measuring tube can be oxidized or nitrogenized for that purpose and a metal oxide or a metal nitride is deposited on the resulting oxide or nitride layer.