| |
TORBAR
produces
an averaged
differential
pressure
(DP)signal
proportional
to the square
of the flow
rate.
The DP output
is normally
piped to
a Differential
Pressure
Transmitter
in order
to generate
an electrical
signal propor
tional to
the flow
rate .A
D.P.gauge
or switch
can be used
to provide
local mechanical
indication
or flow
rate switching.
For certain
applications,
the DP Transmitter
can be directly
mounted
on to the
torbar via
an intergral
3 valve
manifold.The
total flowmeter
package
is called
a TRIBAR.
The MASS
TRIBAR includes
for pressure
and temperature
compensation.
Each TORBAR
is designed
to span
the process
pipe diameter
and comprises
four basic
components:
Outer impact
tube ?ONE
PIECE CONSTRUCTION
Internal
averaging
tube
Low pressure
chamber
Head
The outer
impact tube
has a number
of pressure
sensing
holes facing
upstream
which are
positioned
at equal
annular
points in
accordance
with a loglinear
distribution.
The ?total
pressures?
developed
at each
upstream
hole by
the impact
of the flowing
medium are
firstly
averaged
within the
outer impact
tube and
then to
a second
order(and
more accurately)averaged
within the
internal
averaging
tube. This
pressure
is represented
at the head
as the high
pressure
component
of the DP
output.
The low
pressure
component
is generated
from a single
sensing
hole located
on the downstream
side of
the outer
impact tube.
For bi-direction
flow measurement,
the TORBAR
can be supplied
with the
same number
of downstream
ports as
upstream.
Bi-directional
sensors
have an
inherently
lower mechanical
strength
than the
standard
TORBAR and
the figures
given for
Maximum
Allowable
DP should
be reduced
by 50%. |
