A method for determining an estimated flow rate of fluid flow in a pump comprises: obtaining measurements of the pressure and temperature of fluid at the intake to the pump, the pressure and temperature of the fluid at the discharge from the pump, and the electrical power supplied to the pump; determining values representing either the density of the fluid and the specific heat capacity of the fluid, or the specific fluid enthalpy based on measurements and/or historical data; and calculating an estimated efficiency of the pump and an estimated flow rate of the fluid based on the measured electrical power, the measured temperatures, the measured pressures, the determined value for density and the determined value for specific heat capacity or the determined value for specific fluid enthalpy.

A method for determining an estimated flow rate of fluid flow in a pump comprises: obtaining measurements of the pressure and temperature of fluid at the intake to the pump, the pressure and temperature of the fluid at the discharge from the pump, and the electrical power supplied to the pump; determining values representing either the density of the fluid and the specific heat capacity of the fluid, or the specific fluid enthalpy based on measurements and/or historical data; and calculating an estimated efficiency of the pump and an estimated flow rate of the fluid based on the measured electrical power, the measured temperatures, the measured pressures, the determined value for density and the determined value for specific heat capacity or the determined value for specific fluid enthalpy.

A method for operating a nuclear-magnetic flowmeter in which, when determining a velocity of the medium through a measuring tube, the dependency on properties or the state of a medium is at least reduced. The method exciting a first volume of the magnetized medium flowing at a first velocity within a first measuring section to nuclear-magnetic resonances and a first signal sequence is formed characterizing the nuclear-magnetic resonances of the medium in the first volume, and then, exciting a second volume of the magnetized medium flowing at a second velocity within the first measuring section is excited to nuclear-magnetic resonances and a second signal sequence is formed characterizing the nuclear-magnetic resonances of the medium in the second volume. A quotient sequence is determined from each of the first and second signal sequences, and the first velocity and/or the second velocity is/are determined using the quotient sequence.

An air flow measuring device includes a housing, a sensing part, a temperature sensor, a supporting member, and a protective projection. The housing defines a bypass flow passage which guides a part of air flowing in a duct. The sensing part is disposed in the bypass flow passage to measure a flow rate of air in the bypass flow passage. The sensor detects temperature of air flowing in the duct outside the housing. The supporting member supports the sensor at a predetermined measurement position. The protective projection is a projection, which projects outward from a side surface of the housing and is formed by mold removal in one direction. An end of the protective projection is located outward of the sensor. The protective projection makes contact with an object approaching the sensor from outside the housing to limit contact of the object with the sensor.

An air flow measuring device includes a housing, a sensing part, a temperature sensor, a supporting member, and a protective projection. The housing defines a bypass flow passage which guides a part of air flowing in a duct. The sensing part is disposed in the bypass flow passage to measure a flow rate of air in the bypass flow passage. The sensor detects temperature of air flowing in the duct outside the housing. The supporting member supports the sensor at a predetermined measurement position. The protective projection is a projection, which projects outward from a side surface of the housing and is formed by mold removal in one direction. An end of the protective projection is located outward of the sensor. The protective projection makes contact with an object approaching the sensor from outside the housing to limit contact of the object with the sensor.

A method for operating a Coriolis measurement device comprises the following steps: recording the measured voltages of sensors for sensing measuring tube vibrations and creating an asymmetric sequence of values by way of the amplitudes of the measured voltages for the purpose of diagnosing the Coriolis measurement device, recording at least one stabilization variable and creating a stabilized asymmetric sequence of values based on the stabilization variable, wherein the stabilization variable is one of the following variables or a first or further temporal derivative thereof: a resonant frequency of the measuring tube containing medium or a variable derived therefrom, time or phase difference between measurement signals from the first sensor and the second sensor or a variable derived therefrom, temperature of the measuring tube wall, temperature difference between two measurement points of the measuring tube wall.

A method and apparatus for improving the accuracy of fuel flow meters by compensating for the presence of vapor bubbles generated within the flow meter. The method comprises measuring the temperature of the fuel flowing through the meter and using an algorithm or static lookup table to determine a vapor compensation factor based on that temperature. Because the tendency of fuel to vaporize depends largely on seasonal variations in fuel temperature, applying a temperature-dependent vapor compensation factor promotes year-round accuracy of the flow meter output.

A collar is provided for use with a fluid flow sensor to reduce condensation of a moist gas flowing through the fluid flow sensor. The collar comprises a body defining an interior that defines an airspace between the collar and the housing of the fluid flow sensor when the collar is positioned on the fluid flow sensor. The collar also includes a heat source secured to the body and adapted to heat air contained within the airspace to consequently heat the housing of the fluid flow sensor and the interior surfaces of the sensor to reduce condensation of the moist gas.

A collar is provided for use with a fluid flow sensor to reduce condensation of a moist gas flowing through the fluid flow sensor. The collar comprises a body defining an interior that defines an airspace between the collar and the housing of the fluid flow sensor when the collar is positioned on the fluid flow sensor. The collar also includes a heat source secured to the body and adapted to heat air contained within the airspace to consequently heat the housing of the fluid flow sensor and the interior surfaces of the sensor to reduce condensation of the moist gas.

A device (20) for measuring the flow rate of ink sent to a print head of an ink jet printer, comprising: a restriction (22) of the diameter of the flow of ink, arranged in the path thereof, sensors (26, 28) for measuring the pressure difference (P.sub.in−P.sub.out), between the pressure of fluid upstream of the restriction (P.sub.in) and the pressure of ink downstream of the restriction (P.sub.out).