Abstract: The invention relates to a flow meter for determining a flow of a medium. The flow meter comprises a flow tube for transporting the medium whose flow is to be measured. The flow tube has a supply end and a discharge end disposed downstream thereof. The flow meter is provided with a first flow sensor for measuring the flow of the medium at a first position of the flow tube. The flow meter is provided with a second flow sensor for measuring the flow of the medium at a second position of the flow tube.

Abstract: A fluid flow meter is described that uses thermal tracers to measure flow speed. For fluid flowing through a conduit, the fluid is heated at a heating location in the conduit with a time-dependent heating strength. A speed of sound in fluid flowing in the conduit is measured at multiple sensing locations downstream from said heating location. The flow speed of the fluid is determined from a delay with which the time dependence is detected in the sound speeds measured at the sensing locations. A frequency of the variation of heating strength that is used to determine the flow speed is selected automatically based on the flow speed and/or other circumstances.

Abstract: Coriolis mass flowmeter with a Coriolis tube and with an optical detection device, which optical detection device includes at least one optical sensor for generating a signal that is representative of the movement of the Coriolis tube, the optical sensor comprising a light source and a photosensitive sensor, wherein the optical detection device includes elements for applying a constant voltage across the photosensitive sensor during operation independently of the current generated by the photosensitive sensor in response to incident light, as well as elements for determining the value of the current generated by the photosensitive sensor and converting it into an output signal.

Abstract: Fluid flows through a conduit. To measure flow speed the fluid is heated at a heating location in the conduit with a time-dependent heating strength. A speed of sound in fluid flowing in the conduit is measured at a plurality of sensing locations downstream from said heating location. The flow speed of the fluid is determined from a delay with which the time dependence is detected in the sound speeds measured at said sensing locations. In an embodiment a frequency of the variation of heating strength that is used to determine the flow speed is selected automatically dependent on the flow speed and/or other circumstances.

Abstract: Coriolis mass flowmeter with a Coriolis tube and with an optical detection device, which optical detection device comprises at least one optical sensor for generating a signal that is representative of the movement of the Coriolis tube, said optical sensor comprising a light source and a photosensitive sensor, wherein the optical detection device comprises means for applying a constant voltage across the photosensitive sensor during operation independently of the current generated by the photosensitive sensor in response to incident light, as well as means for determining the value of the current generated by the photosensitive sensor and converting it into an output signal.

Abstract: A mass flowmeter of the Coriolis type with a tube through which a medium flows during operation and with excitation elements for causing the entire tube or part thereof to perform a rotational vibration about a primary axis of rotation during operation. The excitation elements are electromagnetic and do not make contact with the tube during operation and have no components that are fastened to the tube. The tube is made of an electrically conducting material, and the excitation elements include first members for causing an electric current to flow through the tube during operation and second elements for generating a magnetic field at the area of a portion of the tube. The magnetic field is perpendicular to the direction of the current and in operation either the current or the magnetic field changes its sign periodically.

Abstract: A flow sensor of the thermal type having a U-shaped sensor tube with two legs and a connecting limb with two adjoining electrical resistance elements, and with a housing. The sensor tube has an inlet side and an outlet side. The housing has a first and a second housing part of a thermally well-conducting material, each with an inner surface provided with cavities and with an outer surface. The housing parts are placed with their inner surfaces against each other, while the U-shaped sensor tube has a main surface that extends parallel to the inner surfaces. The housing parts surround the connecting limb and the legs of the U-shaped sensor tube such that the sensor tube is thermally clamped in between the housing parts in two locations: a first location situated between its inlet side and the upstream resistance element, and a second location situated between its outlet side and the downstream resistance element.

Abstract: A mass flowmeter of the Coriolis type with a tube through which a medium flows during operation and with excitation elements for causing the entire tube or part thereof to perform a rotational vibration about a primary axis of rotation during operation. The excitation elements are electromagnetic and do not make contact with the tube during operation and have no components that are fastened to the tube. More The tube is made of an electrically conducting material, and the excitation elements include first members for causing an electric current to flow through the tube during operation and second elements for generating a magnetic field at the area of a portion of the tube. The magnetic field is perpendicular to the direction of the current and in operation either the current or the magnetic field changes its sign periodically.

Abstract: A mass flowmeter of the Coriolis type with a tube through which a medium flows during operation and with excitation elements for causing the entire tube or part thereof to perform a rotational vibration about a primary axis of rotation during operation. The excitation elements are electromagnetic and do not make contact with the tube during operation and have no components that are fastened to the tube. More The tube is made of an electrically conducting material, and the excitation elements include first members for causing an electric current to flow through the tube during operation and second elements for generating a magnetic field at the area of a portion of the tube. The magnetic field is perpendicular to the direction of the current and in operation either the current or the magnetic field changes its sign periodically.

Abstract: A mass flowmeter of the Coriolis type with a tube that forms a mechanically closed loop through which a medium flows during operation, and with preferably electromagnetic, contactless excitation elements for causing the loop to rotate in an oscillatory mode about an axis of rotation during operation. The loop has a starting point and an end point. The starting and end points are situated close together and are connected to a flexible inlet tube and a flexible outlet tube, respectively, which extend preferably in parallel and close together. The loop is resiliently suspended from the frame of the flowmeter via the flexible inlet and outlet tubes, which preferably form one integral piece with the tube of the loop.

Abstract: A flow sensor of the thermal type having a U-shaped sensor tube with two legs and a connecting limb with two adjoining electrical resistance elements, and with a housing. The sensor tube has an inlet side and an outlet side. The housing has a first and a second housing part of a thermally well-conducting material, each with an inner surface provided with cavities and with an outer surface. The housing parts are placed with their inner surfaces against each other, while the U-shaped sensor tube has a main surface that extends parallel to the inner surfaces. The housing parts surround the connecting limb and the legs of the U-shaped sensor tube such that the sensor tube is thermally clamped in between the housing parts in two locations: a first location situated between its inlet side and the upstream resistance element, and a second location situated between its outlet side and the downstream resistance element.

Abstract: A mass flowmeter of the thermal type provided with a flow sensor with a flow tube through which a fluid can flow during operation, with a temperature sensor in an upstream position (A) and a heater (H) in a downstream position (B), and power control means and temperature measuring means for keeping the temperature difference between A and B at a predetermined constant value. Between A and B, the flowmeter is provided with means for preventing the temperature at A from rising owing to thermal conduction from B to A via the tube in the case of no flow or a weak flow.

Abstract: A flowmeter of the thermal type with a single flow sensor is connected to control and temperature measuring elements for measuring in a first measuring range by a first measuring method and in a second measuring range by a second measuring method. Detection elements detect the measuring method to be selected on the basis of a flow measurement, and control elements control the flow sensor in accordance with the selected measuring method.

Abstract: A mass flowmeter of the thermal type, having a planar, thin substrate with a sensing surface that can be brought into direct or indirect contact with a flowing fluid during a measurement, wherein electrically controllable heating elements and temperature sensor elements for determining a temperature difference are provided on the sensing surface by a planar technique. The substrate with its sensing surface is present in particular in a cavity of a module into which a feed line and a drain line for the fluid issue.

Abstract: A mass flowmeter of the thermal type, comprising a planar, thin substrate with a sensing surface that can be brought into direct or indirect contact with a flowing fluid during a measurement, wherein electrically controllable heating means and temperature sensor means for determining a temperature difference are provided on the sensing surface by a planar technique. The substrate with its sensing surface is present in particular in a cavity of a module into which a feed line and a drain line for the fluid issue.

Abstract: A mass flowmeter of the thermal type provided with a flow sensor with a flow tube through which a fluid can flow during operation, with a temperature sensor in an upstream position (A) and a heater (H) in a downstream position (B), and power control means and temperature measuring means for keeping the temperature difference between A and B at a predetermined constant value. Between A and B, the flowmeter is provided with means for preventing the temperature at A from rising owing to thermal conduction from B to A via the tube in the case of no flow or a weak flow.

Abstract: The invention relates to a flowmeter of the thermal type with a single flow sensor which is connected to control and temperature measuring means for measuring in a first measuring range by a first measuring method and in a second measuring range by a second measuring method. Detection means detect the measuring method to be selected on the basis of a flow measurement, and control means control the flow sensor in accordance with the selected measuring method.

Abstract: A device for controlling the mass flowrate of a liquid flow in a liquid flow channel, wherein a liquid is transported from a reservoir through the channel by electrosmotic pumping. The channel is associated with thermal flow sensor means which provide an output signal for controlling the pump action.

Abstract: Mass flowmeter comprising a hollow conduit of a heat-conducting material for transporting in a determined flow direction a fluid with a mass flow rate to be measured, a first temperature-sensitive resistor element at a first position in thermal contact with this conduit for supplying heat to said fluid, a temperature sensor and measuring and control means connectable to the resistor element and the temperature sensor, wherein the temperature sensor is provided in thermal contact with the conduit at a second position upstream in relation to said first position, and the measuring and control means are adapted to maintain a constant difference in temperature at said first and second positions.

Abstract: Mass flowmeter comprising a hollow conduit of a heat-conducting material for transporting in a determined flow direction a fluid with a mass flow rate to be measured, a first temperature-sensitive resistor element at a first position in thermal contact with this conduit for supplying heat to said fluid, a temperature sensor and measuring and control means connectable to the resistor element and the temperature sensor, wherein the temperature sensor is provided in thermal contact with the conduit at a second position upstream in relation to said first position, and the measuring and control means are adapted to maintain a constant difference in temperature at said first and second positions.