- Official UK and Ireland channel partner
- UK technical support available
- Model selection and configuration support
Dwyer GFM Gas Mass Flow Meters
Thermal mass flow measurement of clean gases from 10 mL/min to 1000 L/min, with analogue outputs and local or remote display options.
Key highlights
- Measurement only: Clean-gas mass flow without integral control
- Flow ranges: 10 mL/min to 1000 L/min full scale
- Display and outputs: Tiltable LCD options, 0-5 VDC and 4-20 mA
- Wetted materials: Aluminium-based or 316 stainless steel options
- Calibration: NIST-traceable certificate included
The Dwyer Series GFM gas mass flow meter family measures and transmits the flow of clean gases. A straight sensor tube and restrictor flow element divide the gas stream, allowing the electronics to determine mass flow and present it in the selected engineering units.
Series GFM provides measurement only and does not include an integral regulating valve. Applications requiring automatic closed-loop flow control belong to the separate Dwyer Series GFC controller family.
Flow range and gas calibration must match the application. Current catalogue models cover full-scale ranges from 10 mL/min to 1000 L/min. Published range values are based on equivalent nitrogen flow at 21°C and 760 mm Hg, so the required gas and operating conditions should be defined at selection.
Wetted materials and process connections vary by model. GFM-1XXX configurations use anodised aluminium, brass and 316 stainless steel wetted components, while GFM-2XXX configurations use 316 stainless steel. Connection size increases with the selected flow range.
Display-equipped models provide a tiltable LCD, and the meter supplies 0-5 VDC and 4-20 mA outputs for connection to monitoring or data-acquisition equipment. Typical duties include laboratory and analytical systems, OEM test equipment, gas blending verification, burner or furnace gas measurement and general process-gas monitoring.
Key Features
- Thermal mass flow sensing: Straight sensor tube and restrictor arrangement measures clean-gas flow directly
- Specified performance: Accuracy is ±1% of full scale on most models, with ±0.25% full-scale repeatability
- Local display options: 3.5-digit LCD can be tilted through 90 degrees, with remote and panel-mounted readouts also available
- Dual analogue outputs: Linear 0-5 VDC and 4-20 mA signals support monitoring and data acquisition
- High-pressure capability: Most models are rated to 1000 psig, with stated 500 psig limits for X143-X145 models
- Range-matched connections: Compression fittings are sized to suit the selected full-scale flow range
- Gas-specific configuration: Flow range, calibration gas, wetted materials and seal options can be selected for the duty
Specifications
| Measurement and performance | |
| Measurement function | Clean-gas mass flow measurement and transmission; no integral flow-control valve |
| Measurement principle | Thermal mass flow sensor with straight sensor tube and restrictor flow element |
| Flow ranges | 0-10, 0-20, 0-50, 0-100, 0-200, 0-500 or 0-1000 mL/min; 0-2, 0-5, 0-15, 0-30, 0-50, 0-100, 0-200, 0-500 or 0-1000 L/min |
| Reference range conditions | Equivalent nitrogen flow at 21°C (70°F) and 760 mm Hg |
| Accuracy | ±1% of full scale including linearity for most models; ±1.5% of full scale for X143, X144 and X145 models |
| Repeatability | ±0.25% of full scale |
| Response time | Approximately 2 seconds to within ±2% of actual flow |
| Media, calibration and construction | |
| Service | Clean gases compatible with wetted parts; not suitable for liquids |
| Gas calibration | Specify the calibration gas and required engineering units; published gas K-factors are approximate |
| Calibration certificate | NIST-traceable certificate included |
| GFM-1XXX wetted materials | Anodised aluminium, brass, 316 stainless steel and FKM O-rings |
| GFM-2XXX wetted materials | 316 stainless steel and FKM O-rings |
| Seal options | Buna-N, EPR or FFKM O-rings are available as model options |
| Oxygen service | Confirm application suitability and specify oxygen-cleaning service where required |
| Process conditions and installation | |
| Process connections | 1/4 in compression fitting for ranges up to 50 L/min; 3/8 in for 100 and 200 L/min; 1/2 in for 500 L/min; 3/4 in for 1000 L/min |
| Pressure limit | 1000 psig (68.9 bar); 500 psig (34.5 bar) for X143, X144 and X145 models |
| Temperature limit | 0 to 50°C (32 to 122°F) |
| Maximum particulate size | 5 microns; contaminated gas must be filtered before entering the meter |
| Leak integrity | 1 x 10-9 scc/s of helium |
| Installation orientation | Gas path horizontal within ±15 degrees; recalibration may be required for a different orientation |
| Flow direction | Install in the direction indicated by the arrow on the meter |
| Warm-up time | Minimum 15 minutes before checking or adjusting zero |
| Display, outputs and power | |
| Local display | 3.5-digit LCD with 0.5 in characters, tiltable through 90 degrees on display-equipped models |
| Display options | Remote LCD and panel-mounted remote readout configurations available |
| Analogue outputs | Linear 0-5 VDC and 4-20 mA |
| Output loading | 0-5 VDC: 1000 ohm minimum load; 4-20 mA: self-powered sourcing, non-isolated, 0-500 ohm loop resistance |
| Electrical interface | 9-pin D connector; optional output cables available |
| Power input | For units above serial number 340621-1: +12 to +26 VDC, 200 mA maximum; check the meter label because older units may require a specified 12 or 24 VDC supply |
| Compliance | Manufacturer-listed CE compliance |
Scope of Delivery
- Configured Series GFM gas mass flow meter
- NIST-traceable calibration certificate
Support
Able Instruments are an official UK and Ireland channel partner for DwyerOmega, providing application advice, configuration support and quotation assistance for the Series GFM family.
- Model selection: Support matching the gas, full-scale flow range, wetted materials and process connection
- Signal integration: Checks for display arrangement, analogue output, power supply and interface cable requirements
- Installation support: Advice on gas cleanliness, orientation, flow direction, tubing and electrical connection
- Documentation support: Help confirming calibration, NIST certificate and operating-document requirements
Accessories
- GFM-110P 110 V power supply
- GFM-220PE 220 V European power supply
- GFM-CBL4 3 ft cable for 4-20 mA output
- GFM-CBL5 3 ft cable for 0-5 VDC output