Aalborg AFM Data sheet
Mass Flow Meters and Controllers
20
Model AF mass flow meters and controllers are
designed to indicate flow rates and control set flow rates
of gases.
Each of these units incorporates an advanced straight
tube sensor in conjunction with flow passage elements
constructed of stainless steel.
LED readouts of command modules are supplied with 0
to 100 percent calibrations. Zero and span adjustments
are conveniently accessible from outside of the transmitters.
Design Features
Rigid metallic construction.
Maximum pressure of 1000 psig (70 bars).
0-5 Vdc or 4-20mA signals.
Leak integrity 1 x 10
-9
smL/sec of helium.
Accuracy of ±1% F.S.
Totalizer option.
Circuit protection.
Principles of Operation
Metered gases are divided into two laminar flow
paths, one through the primary flow conduit, and
the other through a capillary sensor tube. Both
flow conduits are designed to ensure laminar
flows and therefore the ratio of their flow rates is
constant.
Two precision temperature sensing windings on
the sensor tube are heated, and when flow 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 flow.
Output signals of 0 to 5Vdc or 4 to 20mA are generated indicating mass molecular based flow rates
of the metered gas.
In AFC mass flow controllers the combined gas
streams flow through a proportionating electromagnetic valve with an appropriately selected ori-
fice. The closed loop control circuit continuously
monitors the mass flow output and maintains it
at the set flow rate.
Flow rates are unaffected by temperature and
pressure variations within stated limitations.
AFM
AFC
AFC Mass Flow Controller
NIST
Traceable
Calibration
WWW.AALBORG.COM - E-MAIL : 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.
BULLETIN FM200408 AFC / AFM
AFC and PROC Mass Flow Controllers
AFC mass flow controllers include an electromagnetic control valve that allows the flow to be set to
any desired flow rate within the range of the particular model. The valve is normally closed as a
safety feature to ensure that gas flow is shut off in
case of a power outage.
AF mass flow meters and controllers are designed
to meter and control flow rates of gases.
AF mass flow meters and controllers are available
with flow ranges from 10 sccm to 100LPM [N
2].
Gases are connected by means of 1/4”, 3/8”, or
optional 1/8”compression fittings. These controllers may be used as bench top units or mounted by means of screws in the base.
Transducer power supply ports are fuse and
polarity protected.
Leak Integrity
1 x 10-9smL/sec of helium max to outside environment.
Mass Flow Systems
Complete Mass Flow Systems include Command
Modules, transducers and cables. Command modules contain appropriate power supplies, digital
panel meters with 3-1/2“ digit LED readouts and
high precision potentiometers.External RS-232 or
RS-485 are optional.
Switches in the front panels of Command Modules
select LOCAL or REMOTE reference signals, analog outputs are accessible through convenient 9
pin D-connectors.
Mass Flow Meters and Controllers
AFM
AFC
Specifications
Accuracy : ±1% of full scale, including linearity for gas
temperatures ranging from 59
o
F to 77oF (15oC
to 25
o
C) and pressures of 10 to 60 psia (0.7 to
4.1 bars); ±2% of full scale including linearity
ranging from 41
o
F to 122oF (5oC to 50oC) and
pressures of 5 to 150 psia (0.35 to 10.3 bars).
Repeatability : ±0.2% of full scale.
Time Constant :
AFM Series - 300 ms
AFC2600 (Qmax = 15 sL/min) - 300 ms
AFC3600 (Qmax = 50 sL/min) - 600 ms
AFC4600 (Qmax = 100 sL/min) - 600 ms
Response Time : AFM Series - Approximately 1 second to within
±2% of set flow rate for 25% to 100% of full
scale flow.
AFC2600 (Qmax = 15 sL/min) Approximately 1 second to within ±2% of set
flow rate for 25% to 100% of full scale flow.
AFC3600 (Qmax = 50 sL/min) and
AFC4600 (Qmax = 100 sL/min) Approximately 2 second to within ±2% of set
flow rate for 25% to 100% of full scale flow.
Temperature Coefficient : 0.1% of full scale/
o
C.
Pressure Coefficient :
0.01% of full scale/psi (0.07 bar).
Optimum Gas Pressure : 25 psig (1.73 bars).
Maximum Gas Pressure : 1000 psig (70 bars) maximum. Standard
calibration is at 20 psig (1.4 bars) inlet pressure.
Max. Pressure Drop : Refer to Table 4 and Table 5.
[cm H2O](at full scale flow)
Gas and Ambient Temp : 41
o
F to 122oF (5oC to 50oC).
Leak Integrity : 1 x 10
-9
smL/sec of helium maximum, to the
outside environment.
Materials in Fluid
316 stainless steel, 416 stainless steel, Viton
®
Contact :
O-rings. Optional o-rings, Neoprene
®
,
or Kalrez
®
.
Attitude Sensitivity :
No greater than +15 degree rotation from horizontal
to vertical; standard calibration is in horizontal position.
Output Signals : Linear 0 - 5 Vdc (2000Ω min. load impedance);
4 - 20 mA optional (0 - 500Ω loop resistance);
maximum noise 20 mV peak to peak.
Connections :
AFM/AFC2600,AFM/AFC3600 -1/4” compression
fittings, AFM/AFC4600 - 3/8” compression
fittings. Optional - 1/8” or 3/8” compression
fittings or 1/4” VCR
®
fittings.
Transducer Input Power : AFM/AFC2600 +15 ± 5% Vdc, 80 mA max,1.2W;
-15 ± 5% Vdc, 200 mA max, 3W;
AFC3600/AFC4600 +15 ± 5% Vdc, 220 mA max,
3.3W; -15 ±5% Vdc, 600 mA max, 9W.
Circuit Protection :
Circuit boards have built-in polarity reversal
protection. Replaceable fuses provide power
input protection.
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WWW.AALBORG.COM - E-MAIL : 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.
BULLETIN FM200408 AFC / AFM
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