Aalborg GFM Specifications
MASS FLOW METERS
GFM
Design Features
Rigid metallic construction.
Maximum pressure of 1000 psig (70 bars).
Leak integrity 1 x 10-9 of helium.
NIST traceable certifi cation.
Built-in tiltable LCD readout.
0-5 Vdc and 4-20 mA signals.
Circuit protection.
Can be used as a portable device.
Engineering units or 0 to 100% displays.
TIO Totalizer option.
Typical Aluminum GFM Mass Flow Meter
Principles of Operation
Metered gases are divided into two laminar
fl ow paths, one through the primary fl ow conduit, and the other through a capillary sensor
tube. Both fl ow conduits are designed to ensure laminar fl ows and therefore the ratio of
their fl ow rates is constant.
Two precision temperature sensing windings
on the sensor tube are heated, and when
fl ow takes place, gas carries heat from the
upstream to the downstream windings. The
resultant temperature differential is proportional to the change in resistance of the sensor windings.
A Wheatstone bridge design is used to monitor the temperature dependent resistance
gradient on the sensor windings which is linearly proportional to the instantaneous rate
of fl ow.
Output signals of 0 to 5Vdc and 4 to 20mA
are generated indicating mass molecular
based fl ow rates of the metered gas.
Flow rates are unaffected by temperature
and pressure variations within stated limitations.
General Description
Compact, self-contained GFM mass fl ow
meters are designed to read fl ow rates of
gases. The rugged design coupled with instrumentation grade accuracy provides versatile and economical means of fl ow measurement.
Aluminum or stainless steel models with
readout options of either engineering units
(standard) or 0 to 100 percent displays are
available.
The mechanical layout of the design includes
an LCD readout built into the top of the transducer. This readout module is tiltable over 90
NIST
Traceable
Calibration
BULLETIN 20190620
WWW.AALBORG.COM - E-MAIL 쾷 : INFO@AALBORG.COM - PHONE 845.770.3000 - TOLL FREE IN U.S.A. AND CANADA 1.800.866.3837 ORANGEBURG N.Y. U.S.A.
degrees to provide optimal reading comfort. It
is connected to the transducer by a standard
modular plug, and is also readily removable
for remote reading installations.
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MASS FLOW METERS
GFM
NIST
Traceable
Calibration
GFM 57, 67 and 77
High Flow Mass Flow Meters
TABLE 1 - SPECIFICATIONS FOR GFM
ACCURACY:
CALIBRATIONS:
REPEATABILITY:
RESPONSE TIME:
TEMPERATURE COEFFICIENT:
PRESSURE COEFFICIENT:
MAXIMUM PRESSURE DROP:
GAS AND AMBIENT TEMP.:
OUTPUT SIGNALS:
TRANSDUCER INPUT POWER:
TIME CONSTANT:
GAS PRESSURE:
** MATERIALS IN
FLUID CONTACT:
ATTITUDE SENSITIVITY:
CONNECTIONS:
LEAK INTEGRITY:
CE COMPLIANT:
GFM 17, 37 and 47: ±1.0% of full scale.
GFM 57, 67 and 77: ±1.5% of full scale. OPTIONAL ENHANCED ACCURACY: ±1.0% of full scale.
Performed at standard conditions [14.7 psia (101.4 kPa) and 70 °F (21.1 °C)] unless otherwise requested.
±0.25% of full scale.
Generally 2 seconds to within ±2% of actual fl ow rate over 25 to 100% of full scale.
0.15% of full scale / °C.
0.01% of full scale / psi (0.07 bar).
See Table 3.
32 °F to 122 °F (0 °C to 50 °C). 14 °F to 122 °F (-10 °C to 50 °C) - Dry gases only.
Linear 0-5 Vdc. 1000 ohms min. load impedance and 4-20 mA 0-500 Ohms loop resistance.
Universal +12 to +26 Vdc, 200 mA maximum.
800 ms.
1000 psig (70 bars) maximum GFM 17, 37, 47. 20 psig (1.4 bars) optimum.
500 psig (34.5 bars) GFM 57, 67, 77. 20 psig (1.4 bars) optimum.
a. Aluminum models GFM Series: anodized aluminum, 316 stainless steel, brass and Viton
b. Stainless steel models GFM17S, 37S,47S, 57S, 67S and 77S: 316 stainless steel and Viton
Optional O-rings: Buna® , EPR and Kalrez® .
No greater than +15 degree rotation from horizontal to vertical; standard calibration is in horizontal position.
GFM 17: 1/4" compression fi ttings. Optional: 6mm, 3/8" and 1/8" compression fi ttings or 1/4" VCR
GFM 37: 1/4" compression fi ttings. Optional: 6mm and 3/8" compression fi ttings or 1/4" VCR
GFM 47: 3/8" compression fi ttings.
GFM 57: 3/8" compression fi ttings.
GFM 67: 1/2" compression fi ttings.
GFM 77: 3/4" FNPT fi ttings or 3/4" compression fi ttings.
-9
1 x 10
EN 55011 class 1, class B; EN50082-1.
smL/sec of helium maximum to the outside environment.
®
O-rings.
®
O-rings.
®
.
®
.
BULLETIN 20190620
** The selection of materials of construction, is the responsibility of the customer. The company accepts no liability.
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WWW.AALBORG.COM - E-MAIL 쾷 : INFO@AALBORG.COM - PHONE 845.770.3000 - TOLL FREE IN U.S.A. AND CANADA 1.800.866.3837 ORANGEBURG N.Y. U.S.A.
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