// Medidor
MÁsico
The
World’s Largest Range of Mass Flowmeters
Coriolis Force and the Rheonik Range
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The Coriolis
effect was discovered by physicist Gustave
Gaspard Coriolis during the 1830’s, and
is described as “the inertial force exerted
on an object as a result of movement relative
to a rotating frame of reference.” This
science has been applied to many
technologies: hydraulics, machine performance,
missiles, ergonomics, ocean and atmospheric
circulation and, of course, mass flow metering.
The use of the Coriolis effect as a technique
for liquid and gas mass flow measurement
was firmly established over 20 years ago.
Since then, a number of different designs
have been produced. With the tremendous
electronic signal processing technology
advances that have been made, Coriolis
mass flowmeters have become highly accurate
and reliable instruments.
Rheonik remain at the forefront of this
technology and now produce the world’s
largest and most comprehensive range of
meters. Only the Rheonik range has all
of the following features:-
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At the factory and in regional
offices, Rheonik maintains a team of expert
application and service engineers, offering
best fit technology identification and specification
all the way through to on-site commissioning
and in-depth application troubleshooting
and resolution. A factory trained sales and
service network provides local service and
support worldwide.
The Rheonik range with its unique Omega tube
design allows the most challenging mass flow
metering applications to be solved. The Omega
tube has a torsional oscillation movement
rather than the bending motion associated
with other, more conventional Coriolis meter
designs. The unique mechanical arrangement
of the Omega tube meter allows the use of
tubing with heavier wall thickness giving
higher pressure ratings, combating abrasion
and erosion and eliminating the requirement
for the secondary pressure containment found
with conventional designs. |
· Liquid, sludge and gas
measurement capability
· Models to measure flow rates from as
low as 0.03 kg/h up to 1,500,000 kg/h (0.07
lb/h to 3,300,000 lb/h)
· Sizes up to 12” / DN300
· Pressure ratings up to 900bar / 13,050psig
· Temperature ratings from -255°C to +400°C
/ -425°F to +750°F
· Fiscal/custody transfer approvals (OIML
R117 / NTEP)
· ATEX and CSA hazardous area approvals
covering most of the world
· Extreme resistance to gas bubbles entrained
in the process stream when compared to
conventional Coriolis meters
· Unaffected by viscosity, density or pressure
changes
· Multifunction measurement capability
includes density and temperature
· Available with stainless steel, hastelloy,
monel and tantalum wetted materials as
standard. Other materials on request |
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| Coriolis in action at an olive oil
canning factory |
Highly accurate truck filling station
with
RHM 60 FNT for custody transfer |
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Operating Principle
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The flexibility of the Rheonik
range in terms of applicability and accuracy
is due to the patented mechanical arrangement
of each meter. Each flowmeter has two
measuring tubes parallel to one another and
formed into the unique Omega shape, oscillating
in opposing directions.
The oscillating system is driven with two
high mass cross bars mounted on vertical
torsion rods:-
i) The high mass cross bars stabilize the
torsional movement, either eliminating or
greatly reducing interference from external
vibration and providing continued, reliable
operation with the presence of oscillation
dampening factors such as entrained gas
bubbles or non-homogeneity in the process
stream.
ii) The torsion rods minimize stress on the
tubing, guide tube movement and help “energize”
the torsional motion.
This rugged mechanical arrangement is energy
conserving and requires very little power
input (typically less than 300mW) to maintain
oscillation amplitude.
The design provides for an exceptionally
well balanced mechanism that approaches perpetual
motion once energized, with a natural frequency
that is tuned by
the mass of the cross bars and the elasticity
of the torsion rods. |
Amplitude is controlled by a pair of electromagnetic
coils mounted at each side of the Omega tubes.
The whole mechanism is symmetrical, ensuring
that internal
acceleration forces from the measured process
are counterbalanced. Whenever mass (either
liquid or gas) flows through the oscillating
Omega shaped tubes,
a Coriolis force is generated, causing a
“bending” or “deflection” in the top of the
tubes. This deflection is sensed as a phase
shift between two electronic pick
ups mounted on the tubes. The degree of phase
shift is directly proportional to the mass
flowing within the tubes.
This can perhaps be better understood by
imagining that the oscillation of the meter
measuring tubes (the upper semi-circle of
the Omega tubes) is taking place
on an imaginary disc with points “a” and
“b” on the circumference of the disc. Process
material, starting at point “a” and moving
across the imaginary disc to point “b” (the
path of “effective massflow”) will pass through
a range of differing velocities along the
way.
The Coriolis force (“FC”) generated from
the oscillations of the disc and the effective
mass flow vector is perpendicular to the
movement of the mass across the disc and
is proportional to the mass flow. In the
meter, this force causes the deflection that
is sensed by the two pick-up coils. |
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Sensor Construction Detail
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All Rheonik Coriolis mass flow
meters are manufactured to strictly controlled
procedures and quality standards.
Vacuum brazing is used for the final assembly
of Rheonik Omega tube meters. Each meter
is closely inspected to ensure all joints
are sound and defect free. Meters with removable
cases are sealed with an O-ring, creating
an IP65 / NEMA 4X joint preventing
the ingress of foreign material into the
housing.
Process connections can be either a removable
manifold style or welded directly to the
Omega form tubing to create a truly sealless
meter, ideal for processes with hazardous
materials. |
The pick-up coils and drive coils installed
in the meter are constructed of polyimide
insulated wire encapsulated in epoxy resin.
High temperature versions have
ceramic insulated wiring. Depending upon
the size of the meter, up to four PT-100
temperature sensors are installed in the
meter for temperature compensation.
There are three main parts to Rheonik's patented
Omega tube meter, each of which has a distinct
function.
When added together, they ensure that the
meter produces accurate and repeatable results
(see facing page for additional details):- |
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Omega
Form
· Design permits increased tube wall thickness
· Active measurement section is entire top
half of omega tube and totally decoupled
from the process piping
· No deformation of half round measurement
section with changing pressure gives repeatable
measurement
· Requirement for secondary pressure containment
eliminated! |
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Patented Torsion Rod
· Helps energize torsion oscillation
· Guides tube movement
· Minimizes stress
· Produces large oscillation amplitudes and
extremely good signal to noise ratio for
best accuracies at low flow conditions |
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High Mass Cross Bar
· Reduces susceptibility to external vibration
and processborne dampening conditions ·
Stabilizes torsion movement
· Works in conjunction with torsion rods
to generate harmonic oscillation – tuning
fork perpetual motion |
Technical Data for Sensor Units
TYPE |
Typical
Measuring Range(2) |
Nominal
Rate |
Pressure
Rating in psig(7) |
Standard
process
connections |
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Parallel
(lb/min)
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Serial
(lb/min) |
Parallel
(lb/min) |
For
temperatures
up to 248ºF |
Threaded (1,3)
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Flanged
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RH1015(4) |
0.01-1.32(s) |
0.005
0.66(5) |
1.32 |
4350 (5800) |
¼” NPT |
½” / DN15 |
RHM03 |
0.22 - 11 |
0.11
- 5.5 |
11 |
4350 (2175) |
¼” NPT |
½” / DN15 |
RHM04 |
0.44 - 22 |
0.22
- 11.0 |
22 |
2175 (3625) |
¼” NPT |
½” / DN15 |
RHM06 |
1.1 - 55 |
0.55
- 27.5 |
44 |
5510 (2755) |
½” NPT |
1” / DN25 |
RHM08 |
2.3 - 110 |
1.15
- 55 |
110 |
4205 (13050) |
½” NPT |
1” / DN25 |
RHM12 |
4.5 - 220 |
2.25
- 110 |
165 |
2755 (4205) |
¾” NPT |
1” / DN25 |
RHM15 |
9 - 440 |
4.5
- 220 |
330 |
2175 (4350) |
¾” NPT |
1” / DN25 |
RHM20 |
13 - 660 |
6.5
- 330 |
660 |
1595 (3260) |
1” NPT |
2” / DN50 |
RHM30 |
33 - 1650 |
16.5
- 825 |
1322 |
1885 (5800) |
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2” / DN50 |
RHM40 |
66 - 3300 |
33-1650 |
2756 |
1770 (3625(6)) |
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3” / DN80 |
RHM60 |
130 - 6610 |
65
- 3305 |
5512 |
1450 (2900(6)) |
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4” / DN100 |
RHM80 |
350 - 17635 |
175
- 8820 |
11025 |
1450 (2320(6)) |
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6” / DN150 |
RHM100 |
530 - 26455 |
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22050 |
1450 (3190(6)) |
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8” / DN200 |
RHM160 |
1100 -55115 |
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50715 |
580 (870(6)) |
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12” /DN300 |
(1) ISO G threads available
(2) Typical range for standard meter.
Special ranges available
(3) Different sizes available |
(4) Types RHM007 / 01 replaced
by RHM015
(5) Optional fine tuning:
parallel 0.005 - 1.32 lb/min
serial 0.0025 - 0.66 lb/min
(6) Maximum pressure rating of tube. |
Process connection may derate
overall
meter pressure rating
(7) Pressure rating (in brackets) refers
to
optional heavy duty or special versions
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For the selection of the most suitable meter for
your application, including assessment of pressure
drop, please contact us with full process details.
Accuracy:
Standard Models
Range 1:20 ±0.20% of rate or better
Range 1:50 ±0.50% of rate or better
Repeatability: Better than ±0.10% of rate
Optional Gold Line Models fine tuned to your
application
Range 1:10 ±0.10% of rate or better*
Range 1:20 ±0.12% of rate or better*
Repeatability: Better than 0.05% of rate* |
*Not all models are available with
optional Gold Line performance –
please consult factory |
Accuracy and Repeatability (including
zero drift) are stated at a reference
condition of H20, 14.7psig, 68°F. Range is
turn down from nominal flow rate. Optional
special calibration and fine tuning for enhanced
accuracy in customer specified ranges (including
10w flow) is available.
General Technical Specifications:
Pressure
rating |
Ratings stated
in the table above refer to meter tubes
up to 120°C / 248°F.
Pressure ratings are lower for meters with
higher temperature range.
Most meters are available with higher pressure
ratings. |
Temperature
range
Normal
Extended 1
Extended 2
High
Very high |
RHM type
Temp. in ºF Temp. in ºC Temp.
Class (for EEX ai IIC version)
NT -4 to +248 -20
to +120 T4 – T6
ET1 -328 to +122 -200
to +50 T6 (Ex approval for T > -45ºC
only)
ET2 -49 to +410 -45
to +210 T2 – T3
HT 32 to 662
0 to 350 T1 – T3
VHT 32 to 752
0 to 400 No EEx approval |
Wetted
materials parts |
Standard material
of construction is 316Ti/1.4571
Stainless Steel.
Optional materials include Hastelloy, Tantalum,
Monel and Inconel. Consult factory for
others. PTFE is used in meters requiring
seals. |
The above tables are a summary of the standard
meter range. Special and custom version meters
are available on request.
All hazardous area meters carry ATEX and/or CSA/NRTL
approvals. All standard versions comply with
EU PED and ASME standards.
The RHE14 ¡s low cost, compact and ideal for
OEM applications. I/O includes 4-20mA, pulse,
flow direction and RS232 serial data. Programming
and configuration by SensCom software.
The RHE06 is ATEX approved for hazardous area
installation and offers pulse output and Error
and Flow Direction. *The RHE06F+ has double pulse
outputs with 90º phase shift for custody transfer
applications.
All other Rheonik transmitters have clear, easy
to read local displays and intuitive, menu driven
set-up and configuration functions. All include
diagnostics for fault finding and tuning. Features
include low flow cutoff, response time, multiple
I/O, selectable units and full scaling capabilities.
All settings are stored in non-volatile memory
and I/O is galvanically or optically isolated.
RHE 07/08/11
Programming: Programmable via
3 buttons
Analogue outputs: 2 assignable
and scalable 0/4-20mA for flow, density, temperature
or volume,
galvanically isolated, max. load < 500 Ohm.
Digital outputs: 1 frequency
/ pulse output (0-10kHz, max.
30V / 50 mA), 3 status outputs
(limit, error/alarm, flow direction etc.)
Digital inputs: 2 status inputs
(remote zero, hold totalizer, tot. reset, quit
error/alarm)
RS232/422/485: Serial interface or HART options
available. For details see individual
datasheet.
Display: 2 line, 16 character
backlit LCD display
Features: Includes built-in
single and dual stage batch controller
RHE07C has double pulse output for custody transfer
RHE 12
Programming: Programmable
via 2 sensors behind the glass cover.
Analogue outputs: 1 programmable
0/4-20 mA output, galvanically isolated (intrinsically
safe optional)
Digital outputs: 1 frequency
/ pulse output (intrinsically
safe optional), HART
Error / Alarm condition output
(22 mA) RS232 / 485 options
available.
Display: 2 line, 16 character
backlit LCD display.
Profibus PA / Foundation
Fieldbus in development
General Data for alI Transmitters:
Ambient temperature: -40 to
60°C
Power consumption: < 15 Watt
RHE12 < 5 Watt
RHE14 < 1 Watt |
RHE 06, RHE 06F+, RHE07, RHE 08 and RHE
14 transmitters to
be installed outside of hazardous area (RHE
08 can be installed in
Cl. 1, Div. 2 area).
RHE 11/12 can be installed in the hazardous
area.
RHM can be installed in hazardous area (ATEX
EEx ia IIC T6-T1 /
CSA Cl. 1, Div.1, Gr. ABCD) if connected
to approved RHE unit. |
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