Dwyer GFM User Manual
Technical Data Sheet No. TD9411M Rev. L
Date of Issue: July 2009
OPERATING MANUAL
FOR GFM MASS FLOW METERS
P.O. Box 373
Michigan City, IN 46361 USA
Phone: (219) 879-8000
FAX: (219) 879-9057
e-mail: info@dwyer.com
Internet: http://www.dwyer-inst.com
Dwyer reserves the right to make changes to information and specifications in this
manual without notice.
CAUTION:
This product is not intended to be used in life support applications!
CAUTION:
K-Factors at best are only an approximation. K factors should not
be used in applications that require accuracy better than +/- 5 to 10%.
TABLE OF CONTENTS
1. UNPACKING THE GFM MASS FLOW METER.........................................
1.1 Inspect Package for External Damage.................................................
1.2 Unpack the Mass Flow Meter...............................................................
1.3 Returning Merchandise for Repair.......................................................
2. INSTALLATION.......................................................................................
2.1 Primary Gas Connections...............................................................
2.2 Electrical Connections.....................................................................
2.3.1 Remote LCD Readouts.....................................................................
2.3.2 Panel Mounting Readouts...............................................................
3. PRINCIPLE OF OPERATION..................................................................
4. SPECIFICATIONS...................................................................................
4.1 CE Compliance.................................................................................
5. OPERATING INSTRUCTIONS.................................................................
5.1 Preparation and Warm Up................................................................
5.2 Flow Signal Output Readings..........................................................
5.3 Swamping Condition.......................................................................
6. MAINTENANCE........................................................................................
6.1 Introduction.....................................................................................
6.2 Flow Path Cleaning..........................................................................
6.2.1 Restrictor Flow Element (RFE)........................................................
6.2.2 GFM-110 /111 models.........................................................................
6.2.3 GFM-1131 to 1142 models..................................................................
6.2.4 GFM-1144 /1145 models.....................................................................
7. CALIBRATION PROCEDURES.................................................................
7.1 Flow Calibration...............................................................................
7.2 Calibration of GFM Mass Flow Meters..............................................
7.2.1 Connections and Initial Warm Up.....................................................
7.2.2 ZERO Adjustment.............................................................................
7.2.3 SPAN Adjustment............................................................................
7.3 Linearity Adjustment..........................................................................
7.3.1 Connections and Initial Warm Up....................................................
7.3.2 ZERO Adjustment.............................................................................
7.3.3 25% Flow Adjustment......................................................................
7.3.4 50% Flow Adjustment......................................................................
7.3.5 75% Flow Adjustment......................................................................
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7.3.6 100% Flow Adjustment....................................................................
7.4 LCD Display Scaling.........................................................................
7.4.1 Access LCD Display Circuit..............................................................
7.4.2 Adjust Scaling..................................................................................
7.4.3 Change Decimal Point......................................................................
8. TROUBLESHOOTING.............................................................................
8.1 Common Conditions........................................................................
8.2 Troubleshooting Guide.....................................................................
8.3 Technical Assistance.......................................................................
9. CALIBRATION CONVERSIONS FROM REFERENCE GASES.......................
APPENDIX 1 COMPONENT DIAGRAM.......................................................
APPENDIX 2 GAS FACTOR TABLE (“K” FACTORS).....................................
APPENDIX 3 DIMENSIONAL DRAWINGS....................................................
PARTS OF THE FLOW METER..............................................
APPENDIX 4 WARRANTY..........................................................................
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1. UNPACKING THE GFM MASS FLOW METER
1.1 Inspect Package for External Damage
Your GFM Mass Flow Meter was carefully packed in a sturdy cardboard carton,
with anti-static cushioning materials to withstand shipping shock. Upon receipt,
inspect the package for possible external damage. In case of external damage to
the package contact the shipping company immediately.
1.2 Unpack the Mass Flow Meter
Open the carton carefully from the top and inspect for any sign of concealed shipping damage. In addition to contacting the shipping carrier please forward a copy
of any damage report to your distributor or Dwyer directly.
When unpacking the instrument please make sure that you have all the items
indicated on the Packing List. Please report any shortages promptly.
1.3 Returning Merchandise for Repair
Please contact the customer service representative of your distributor or Dwyer if
you purchased your Mass Flow Meter directly, and request a Return
Authorization Number (RAN). Equipment returned without an RAN will not
be accepted. Dwyer reserves the right to charge a fee to the customer for equip-
ment returned under warranty claims if the instruments are tested to be free from
warrantied defects.
Shipping charges are borne by the customer. Meters returned “collect” will not be
accepted!
It is mandatory that any equipment returned for servicing be purged and neutralized of any dangerous contents including but not limited to toxic, bacterially infectious, corrosive or radioactive substances. No work shall be performed on a
returned product unless the customer submits a fully executed, signed SAFETY
CERTIFICATE. Please request form from the Service Manager.
2. INSTALLATION
2.1 Primary Gas Connections
Please note that the GFM Mass Flow Meter will not operate with liquids. Only
clean gases are allowed to be introduced into the instrument. If gases are contaminated they must be filtered to prevent the introduction of impediments into the
sensor.
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CAUTION: GFM TRANSDUCERS SHOULD NOT BE USED FOR MONITORING
OXYGEN GAS UNLESS SPECIFICALLY CLEANED AND PREPARED FOR SUCH
APPLICATION.
For more information, contact your distributor or Dwyer.
Attitude sensitivity of the Mass Flow Meter is ±15. This means that the gas flow
path of the Flow Meter must be horizontal within those stated limits. Should there
be need for a different orientation of the meter, re-calibration may be necessary. It
is also preferable to install the GFM transducer in a stable environment, free of frequent and sudden temperature changes, high moisture, and drafts.
Prior to connecting gas lines inspect all parts of the piping system including ferrules and fittings for dust or other contaminant’s.
Be sure to observe the direction of gas flow as indicated by the arrow on the front
of the meter when connecting the gas system to be monitored.
Insert tubing into the compression fittings (except GFM-1145) until the ends of the
properly sized tubings home flush against the shoulders of the fittings.
Compression fittings are to be tightened according to the manufacturer's instructions to one and one quarter turns. Avoid over tightening which will seriously damage the Restrictor Flow Elements (RFE's)!
Using a Helium Leak Detector or other equivalent method perform a thorough
leak test of the entire system
. (All GFM's are checked prior to shipment for leak-
age within stated limits. See specifications in this manual.)
2.2 Electrical Connections
GFM transducers require a +12VDC (+24VDC optional) power supply with a minimum current rating of 200mA to operate. The operating power input is supplied
via the DC power jack or
the 9-pin “D” connector located at the side of the flow
transducer enclosure. On GFM's purchased without an LCD readout, a readout
panel meter, digital multimeter, or other equivalent device is required to observe
the flow signal.
DO NOT CONNECT 24Vdc POWER SUPPLY UNLESS YOUR GFM METER WAS
ORDERED AND CONFIGURED FOR 24Vdc.
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PIN FUNCTION
1 Remote LCD display signal
2 0 to 5 VDC output indication
3 0 to 5 VDC common
4 Power supply, positive
5 Power supply, common
6 Remote LCD display reference
7 (unassigned)
8 4 to 20 mA output indication
9 4 to 20 mA common
FIGURE 2.a - 9-PIN “D” CONNECTOR PINOUTS FOR GFM TRANSDUCER.
IMPORTANT NOTES:
In general, “D” Connector numbering patterns are standardized. There are, however, some connectors with nonconforming patterns and the numbering sequence
on your mating connector may or may not coincide with the numbering sequence
shown in our pin configuration table above. It is imperative that you match the
appropriate wires in accordance with the correct sequence regardless of the particular numbers displayed on your mating connector.
Make sure power is OFF when connecting or disconnecting any cables in the system.
When connecting power to the GFM mass flow meter via the DC power jack, do
not connect any power supply to the 9-pin 'D' Connector. The DC power jack has
a center positive polarity.
When battery use is required to power the GFM, use only the optional battery and
accompanying charger available from Dwyer.
The power input is protected by a 750mA M (medium time-lag) resettable fuse. If
a shorting condition or polarity reversal occurs, the fuse will cut power to the flow
transducer circuit. Disconnect the power to the unit, remove the faulty condition,
and reconnect the power. The fuse will reset once the faulty condition has been
removed.
Cable length may not exceed 9.5 feet (3 meters).
Use of the GFM flow transducer in a manner other than that specified in this manual or in writing from Dwyer, may impair the protection provided by the equipment.
2.3.1 Remote LCD Readouts
GFM Mass Flow Meters are available with optional remote reading LCD displays
supplied with a three foot long wire to accommodate most applications. This configuration includes the upper block element which serves as the LCD readout
mounting. Special lengths of remote extension wiring (up to 9.5 feet [3 meters])
are available on request.
2.3.2 Panel Mounting Readouts
Another option for the GFM Mass Flow Meter is the Panel Mounting Remote
Readout. In this configuration the LCD readout is supplied with a three foot long
extension wire, and no aluminum housing around the LCD. The LCD readout for
panel mounting includes a bezel with two plastic screws which conveniently fit into
a rectangular cut-out for panel mounting (see Figure 2.b).
FIGURE 2.b - CUTOUT DIMENSIONS FOR LCD PANEL MOUNTING.
3. PRINCIPLE OF OPERATION
The stream of gas entering the Mass Flow transducer is split by shunting a small
portion of the flow through a capillary stainless steel sensor tube. The remainder
of the gas flows through the primary flow conduit. The geometry of the primary conduit and the sensor tube are designed to ensure laminar flow in each branch.
According to principles of fluid dynamics the flow rates of a gas in the two laminar
flow conduits are proportional to one another. Therefore, the flow rates measured
in the sensor tube are directly proportional to the total flow through the transducer.
In order to sense the flow in the sensor tube, heat flux is introduced at two sections of the sensor tube by means of precision wound heater-sensor coils. Heat is
transferred through the thin wall of the sensor tube to the gas flowing inside. As
gas flow takes place heat is carried by the gas stream from the upstream coil to
the downstream coil windings. The resultant temperature dependent resistance
differential is detected by the electronic control circuit. The measured gradient at
the sensor windings is linearly proportional to the instantaneous rate of flow taking place.
An output signal is generated that is a function of the amount of heat carried by
the gases to indicate mass-molecular based flow rates.
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4. SPECIFICATIONS
FLOW MEDIUM: Please note that GFM 1101 thru 1145 Mass Flow Meters are designed to
work with clean gases only. Never try to meter or control flow rates of liquids with any GFM's.
CALIBRATIONS: Performed at standard conditions [14.7 psia (1.01 bars) and 70
F
F
(21.1
F
C)] unless otherwise requested or stated.
ENVIRONMENTAL (per IEC 664): Installation Level II; Pollution Degree II.
ACCURACY: ±1.5% of full scale, including linearity for gas temperatures ranging from 59
F
F to 77FF (15FC to 25FC) and pressures of 5 to 60 psia (0.35 to 4.1 bars).
REPEATABILITY: ±0.5% of full scale.
TEMPERATURE COEFFICIENT: 0.15% of full scale /
F
C.
PRESSURE COEFFICIENT: 0.01% of full scale /psi (0.07 bar).
RESPONSE TIME: 800 ms time constant; approximately 2 seconds to within ±2% of set
flow rate for 25% to 100% of full scale flow rate.
GAS PRESSURE: 1000 psig (69 bars) 10, 50 and 100 L/min; 500 psig (34.5 bars) 200,
500 and 1000 L/min; optimum pressure is 20 psig (1.4 bars).
GAS AND AMBIENT TEMPERATURE: 32
F
F to 122FF (0FC to 50FC).
RELATIVE GAS HUMIDITY: Up to 70%.
LEAK INTEGRITY: 1 x 10
- 7
sccs He max. to the outside environment.
ATTITUDE SENSITIVITY: 1% shift for a 90 degree rotation from horizontal to vertical; standard calibration is in horizontal position.
OUTPUT SIGNALS: Linear 0-5 VDC (1000 Ω minimum load impedance) and 4-20 mA
(0-500 loop Ω resistance); 20 mV peak to peak max noise.
Contact your distributor or Dwyer for optional RS232 or IEEE488 interfaces.
TRANSDUCER INPUT POWER: +12 VDC, 200 mA maximum; +24 VDC optional.
Power input is protected by a 750mA M (medium time-lag) resettable fuse, and a rectifier
diode for polarity protection.
WETTED MATERIALS:
GFM-110 thru 1145: Anodized aluminum, brass, and 316 stainless steel with
VITON
®
O-rings seals; BUNA-N®, NEOPRENE®or KALREZ®O-rings are optional.
GFM-1101 thru 1145: 316 stainless steel with VITON
®
O-rings seals; BUNA-N®, NEOPRENE
®
or KALREZ®O-rings are optional.
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Dwyer makes no expressed or implied guarantees of corrosion resistance of mass flow
meters as pertains to different flow media reacting with components of meters. It is the
customers' sole responsibility to select the model suitable for a particular gas based on the
fluid contacting (wetted) materials offered in the different models.
INLET AND OUTLET CONNECTIONS:
GFM-110 /111 /113 -1/4" compression fittings
GFM-1142 /1143 -3/8" compression fittings
GFM-1144 -1/2" compression fittings
GFM-1145 -3/4" FNPT fittings
LCD DISPLAY: 3½ digit LCD (maximum viewable digits “1999”), 0.5 inch high characters.
On GFM 1101-1145 meters aluminum or stainless steel models the LCD display is built into
the upper block element and may be tilted over 90 degrees for optimal viewing comfort.
Remote or panel mounting remote reading is optional.
Standard readings are in direct engineering units for the given gas and flow rate (i.e. standard liters /minute [slpm], standard cubic centimeters /minute [sccm], standard cubic feet
/hour [scfh], etc.). 0 to 100% LCD calibration scaling is available upon request at time of
order. Contact your distributor or Dwyer when non-standard display settings are desired.
TRANSDUCER INTERFACE CABLE: Optional shielded cable is available mating to the GFM
transducer 9-pin “D” connector. [Cable length may not exceed 9.5 feet (3 meters)]
4.1 CE Compliance
Any model GFM bearing a CE marking on it, is in compliance with the below stated test standards currently accepted.
EMC Compliance with 89 /336 /EEC as amended; Emission Standard: EN
55011:1991, Group 1, Class B Immunity Standard: EN 55082-2:1992
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