The invention consists in a capacitative electromagnetic flow meter
in which excitation is performed at a frequency above the commercially
available frequency and having a characteristic correction filter
that corrects the gain frequency characteristic of the exciting
current such that the exciting flux waveform has a flat section.
In the detection unit, the value of the electrostatic capacitance
between the face electrodes 4A, 4B and guard electrodes 5A, 5B is
made smaller than the value of the electrostatic capacitance between
the detecting face electrodes 4A, 4B and the fluid to be measured.
The exciting coils are fixed to a cylindrical yoke, being electrostatically
screened by coil fixing plates. Fixing by an earth ring is performed
with this cylindrical yoke and the two ends of the measurement tube
being symmetrical with respect to the tube axis and electrode axes.
In addition, fixing is effected by filling the entire interior of
the detection unit with epoxy resin.
A flow meter comprises an inflow chamber having a first fluid inlet,
an outflow chamber housed in the inflow chamber and having a second
fluid inlet, which is in fluid communication with the inflow chamber,
and a fluid outlet by which fluid can drain from the outflow chamber,
and a sensing device having a elongate sensor which is positioned
at, or adjacent to and downstream of, the second fluid inlet. The
second fluid inlet is of limited dimensions so that, in use, a head
of fluid is formed in the inflow chamber and the flow rate of the
fluid passing through the second fluid inlet is monitored based
on the extent of the elongate sensor which is covered by the fluid.
A flow meter and electrically operable valve assembly having integral
flow meters provide detection of very low water flows, along with
ease of installation and compact packaging for a water supply control
system. The flow detection is particularly useful for systems that
control household water supplies to prevent flooding, but is also
useful in other applications such as agricultural and industrial
systems where low water flow rates must be determined. All of the
controls and features are integrable within a compact package that
occupies essentially the same volume and piping space as a conventional
electrically operable valve.
This ultrasonic flow meter is provided for measuring flow volume
by determining the flow rate of a liquid from the difference in
propagation times of ultrasonic waves in both directions between
measuring units by providing measuring units having transducer at
an interval in the lengthwise direction on a measuring pipe through
which liquid flows. A pair of mounting members are provided in a
lower case of a case serving as a base at an interval wider than
that of measuring units. The measuring pipe is held by respective
retaining indentations to the outside in the axial direction of
measuring units by facing a left mounting member and a right mounting
member that compose the mounting members. In addition, an insulating
material is filled into the case so as to cover the measuring units
and the measuring pipe.