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The flow rate of a fluid can be measured using an ultrasonic flow
meter according to the present invention with a higher measuring
accuracy and a lower cost. The feature of the invention consists
in an ultrasonic flow meter comprising a measurement tube for flowing
a fluid to be subjected to measurement, a first oscillator fitted
to the outer circumference of the measurement tube, a second oscillator
fitted to the outer circumference of the measurement tube at a predetermined
interval along the flow of the fluid from the first oscillator and
an acoustic filter fitted to the measurement tube for cutting high
frequency range of the oscillating wave propagating through the
oscillating tube, in which the flow rate of a fluid is measured
based on a time difference between a time required when the ultrasonic
wave from the upstream oscillator reaches the downstream oscillator
and another time required when the ultrasonic wave from the downstream
oscillator reaches the upstream oscillator.
Improvement in a mass air flow meter having a static pressure manifold
disposed upstream from an air flow path for sample air and capable
of accumulating a volume of air therein, the flow path constructed
to receive an air flow transducer, the static pressure manifold
having an inlet arrangement in communication with the kinematic
main air flow traveling through the meter so as to be capable of
sensing different static pressures thereof, the static pressure
manifold having a single outlet serving as the sole inlet for the
sample air to be measured by the air flow transducer, the static
pressure of the air accumulated in the static pressure manifold
being such that it functions as a resultant average of the different
static pressures sensed at its inlet arrangement, the static pressure
manifold providing substantial immunity for the meter in respect
to turbulent air flow upstream therefrom.
Claims
A flow meter for a multiphase flow which comprises a cross-correlation
flow meter (26) for measuring basic values to calculate component
ratios of respective fluids constituting a multiphase fluid (2)
comprising a gas and a plurality of liquids in a pipe (1) through
which the multiphase fluid flows; and an arithmetic circuit (22)
for calculating flow rates of the respective fluids, which acquires
information concerning ratios of liquid phase components of the
multiphase fluid (2) on the basis of both measured values obtained
by the cross-correlation flow meter (26) at an instance when the
pipe (1) is filled with liquid alone during the passage of the multiphase
fluid (2) through the pipe (1) provided with the cross-correlation
flow meter (26) and characteristic values of the respective fluids
of the multiphase fluid (2), acquires information concerning ratios
of the respective fluids from a time average of the measurements
obtained by the cross-correlation flow meter (26) and the respective
characteristic values, then obtains the component ratios of the
respective fluids by utilizing the fact that a sum of the component
ratios of the respective fluids becomes (1), calculates an average
flow velocity of the multiphase fluid (2) from time between fluctuations
of the measured values obtained by the cross-correlation flow meter
(26), and calculates flow rates of the respective fluids by utilizing
the respective component ratios and the average flow velocity.
An ultrasonic gas meter housing member is configured to provide
an associated multi-configuration ultrasonic gas meter assembly.
The housing member is installable in an ultrasonic gas flow meter
which includes an internal flow measurement tube along which gas
travels for flow measurement, the tube having an inlet end and an
outlet end. The ultrasonic gas meter housing member includes a closed
back portion and a front portion spaced from the back portion to
define a space for receiving the internal flow measurement tube
such that the tube extends across the internal space of the housing
member. At least one wall portion extends between the back portion
and the front portion, the wall portion having a first opening and
a second opening therethrough for connection of the housing member
to a gas inlet pipe and a gas outlet pipe. The gas meter housing
member is symmetrical about a plane which divides the housing member
into a first portion and a second portion. The symmetrical configuration
enables the housing member to receive the flow measurement tube
in both a first orientation in which the first and second opening
face in a first direction and the inlet end of the flow measurement
tube is positioned in the first portion of the housing member and
the outlet end is positioned in the second portion, and a second
orientation in which the first and second opening face in a second
direction substantially perpendicular to the first direction and
the inlet end of the flow measurement tube is positioned in the
second portion of the gas meter housing member and the outlet end
is positioned in the first portion. The first and second orientations
are particularly useful in enabling the housing member to be used
both in gas meter installation sites where the gas pipes extend
downward and in gas meter installation sites where the gas pipes
extend upward.
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