A Karman vortex flow meter in which a main passage 1 and a bypass
passage 2 are adjacent to each other; a throttle portion 12 is formed
at the inlet of the bypass passage to continuously reduce the cross-sectional
surface area of the passage, and a flared portion 14 is formed in
the bypass passage 2 so that the cross-sectional surface area of
the passage is continuously enlarged from an intermediate portion
of the passage to the outlet of it. Further, the inlets and the
outlets of the main passage and the bypass passage are each arranged
in single planes perpendicular to the flow direction of the fluid
to be measured, and the boundary portions 16 17 between the main
passage and the bypass passage 2 are respectively formed to have
a smallest thickness.
A fluid flow meter has a housing with a fluid inlet and a fluid
outlet and defining therebetween a fluid flow path. The flow meter
has a flexible membrane having a inlet end mounted at an inlet region
of the fluid flow path and a outlet end mounted at an outlet region
of the fluid flow path. The flexible membrane produces undulating
motion in response to fluid flow in the fluid flow path. Fluid flow
rate is measured by sensing the undulating motion of the membrane.
Performance of the meter is enhanced by laminating a layer of material
to the membrane.
The flow meter has in a substantially cylindrical inner housing
(1) a helically designed diffuser (4), which imparts a swirl to
the medium flowing through the inner housing. Downstream of the
diffuser there is rotatably mounted a rotor (8), which has blades
(13) extending from its rotational spindle (9) as well as a ring
(14) which connects the blade ends to one another and is coaxial
to the spindle. The rotor (8) is set in rotation by impingement
of the blades (13) by the flowing medium. On the outer circumferential
surface (15) of the ring (11) there is on a circular line a multiplicity
of markings (16) arranged at equal angular intervals from one another.
Through a window (18) in the inner housing (1), a light beam strikes
the outer circumferential surface (15) of the ring (14), provided
with the markings (16). Upon rotation of the rotor (8), the sequence
of markings is transmitted by an optical-fibre cable (20) and sensed
by a sensor (21), so that from the signals received the flow rate
can be determined. The flow meter has the advantage that the medium
to be measured does not have to be transparent as in the application
of the light barrier and that the multiplicity of markings allows
an increase in the measuring accuracy.
A mass flow meter for flowing media which works on the Coriolis
Principle includes a straight measuring pipe carrying the flow medium,
an oscillator acting on the measuring pipe and two transducers detecting
Coriolis forces and/or Coriolis oscillations based on Coriolis forces.
The meter also has a carrier pipe holding the measuring pipe, the
oscillator and the transducers and two temperature sensors that
detect the temperature of the measuring pipe and correct the measured
value depending on the temperature of the measuring pipe. The measuring
pipe and the carrier pipe are connected to one another in a way
that excludes relative axial movements, and the axial distance between
the connecting points of the measuring pipe carrier pipe represents
the oscillation length of the measuring pipe. The mass flow meter
is designed so that, in a simple way, the measured value is largely
independent from temperature changes and from forces acting from
the outside and so that a length-change sensor that detects changes
in the oscillation length of the measuring pipe can correct the
measured value depending on the oscillation length of and stress
on the measuring pipe.