The ABB Purgemaster FGM6100 is a glass tube variable area flowmeter for low-capacity flow measurement. It is designed for clean, low-viscosity liquids and gases and provides direct visual indication through a glass measuring tube.
Compared with larger glass tube variable area flowmeters, the FGM6100 is specifically intended for small flow applications. ABB highlights its use for purging control lines and instrument enclosures, while also listing fluid sampling, liquid specific gravity measurement, level measurement and similar services.
The flowmeter uses a corrosion-resistant, high-strength stainless steel body with a quick snap-in tube construction and a safety-tested operator protection shield.
Key Features
• Low-capacity flow measurement for liquids and gases
• Glass measuring tube for direct visual flow indication
• Corrosion-resistant, high-strength stainless steel body
• Quick and easy snap-in tube construction
• Safety-tested operator protection shield
• Water flow range from 0.53 to 2200 cm³/min
• Typical 10:1 flow turndown
• 38, 76, 125 or 250 mm nominal scale lengths
• 1/4 in. NPT or BSPP female connections
• Vertical or horizontal connection orientation
• Vertical in-line, wall/surface or back-of-panel mounting
• Brass or 316 stainless steel end connections
• Glass, sapphire, Carboly, tantalum or stainless steel floats
• Up to two proximity sensor alarms
• Basic mechanical flow indication without external power supply
Measuring Principle
The FGM6100 uses the variable area flow principle. The process medium flows through a tapered glass measuring tube and moves the float according to the flowrate. The float position can then be read against the flow scale.
As a mechanical variable area flowmeter, the FGM6100 provides local visual indication without requiring an external power supply for the basic flow measurement function.
Measuring Range
The FGM6100 is designed specifically for low-capacity flow measurement.
For water, ABB specifies a flow range of 0.53 to 2200 cm³/min, with a typical flow turndown of 10:1.
The actual flow range for gases or other liquids depends on the selected measuring tube, float and process-medium properties. The exact configuration should therefore be selected according to the medium, density, viscosity and required flowrate.
Operating Conditions
Depending on the selected configuration, the FGM6100 supports:
• Operating pressure: up to 18 bar
• Operating temperature: up to 120 °C
• Accuracy: Class 1.6 to Class 10
• Nominal scale lengths: 38, 76, 125 or 250 mm
• Flow turndown: typically 10:1
• Measuring tube material: glass
Accuracy depends on the selected tube diameter and float type. The actual pressure and temperature limits should also be checked against the final configuration before ordering.
Mounting Options
The FGM6100 provides several installation possibilities:
• Vertical in-line installation
• Wall or surface mounting
• Back-of-panel mounting
• Vertical or horizontal connection arrangement
This flexibility makes the instrument suitable for both individual flow monitoring points and integration into packaged instrumentation panels.
Process Connections
The FGM6100 uses 1/4 in. NPT or BSPP female connections. The connections are available for vertical or horizontal arrangements according to the selected configuration.
End connection materials include brass or 316 stainless steel, allowing the flowmeter to be selected according to the application and fluid compatibility requirements.
Materials
The measuring tube is made from glass, while the main body uses corrosion-resistant, high-strength stainless steel.
Available float materials include:
• Glass
• Sapphire
• Carboly
• Tantalum
• Stainless steel
The choice of float material depends on the measured medium, required flow range and application conditions.
Alarm Options
The FGM6100 can be equipped with up to two proximity sensors for flow monitoring and alarm functions.
This provides a simple way to add flow-limit monitoring while retaining the mechanical visual indication of the glass tube flowmeter.
Suitable Applications
Control Line Purging
The FGM6100 is particularly suitable for purging control lines, one of the primary applications identified by ABB. Its small flow capacity makes it appropriate where only a controlled low flow of gas or liquid is required.
Instrument Enclosure Purging
The flowmeter can also be used for purging instrument enclosures, providing a direct visual indication of the purge flowrate.
Fluid Sampling
The FGM6100 can be used in fluid sampling systems where a small and controlled flow needs to be monitored locally.
Liquid Specific Gravity Measurement
ABB also lists liquid specific gravity measurement among the applications for the Purgemaster series.
Low-Flow Process Monitoring
The FGM6100 can be applied to other small-flow services involving clean, low-viscosity liquids or gases where a compact mechanical flow indicator is preferred.
Selection Notes
When selecting an ABB FGM6100, confirm the following information:
• Measured medium
• Liquid or gas service
• Normal and maximum flowrate
• Required measuring range
• Medium density
• Medium viscosity
• Operating pressure
• Operating temperature
• Required connection type: NPT or BSPP
• Required connection orientation
• Mounting arrangement
• Float material
• Required scale length
• Whether proximity sensor alarms are required
The FGM6100 is specifically a low-capacity flowmeter, so it should not be selected simply because the pipe connection size matches. The actual process flowrate and medium properties should determine the measuring tube and float configuration.
FAQ
What type of flowmeter is the ABB FGM6100?
The FGM6100 is a glass tube variable area flowmeter, also commonly called a glass tube rotameter or float flowmeter. ABB markets it under the Purgemaster FGM6100 name.
What is the FGM6100 mainly used for?
Its main applications include control line purging and instrument enclosure purging. ABB also lists fluid sampling, liquid specific gravity measurement, level measurement and similar services.
What media can the FGM6100 measure?
The FGM6100 is designed for clean, low-viscosity liquids and gases.
What is the water flow range?
The ABB specification gives a water flow range of 0.53 to 2200 cm³/min, depending on configuration.
What is the maximum operating pressure?
The maximum operating pressure is up to 18 bar, depending on configuration.
What is the maximum operating temperature?
The maximum operating temperature is up to 120 °C, subject to the selected configuration.
Does the FGM6100 need an external power supply?
The basic variable area flow indication is mechanical and does not require an external power supply. Optional proximity sensors can be added for alarm functions. ABB's variable area flowmeter family is also described as suitable for mechanical backup measurement because no external power supply is needed.
How is the FGM6100 different from the ABB FGM1190?
The FGM6100 is designed for low-capacity flow measurement, with a water range of 0.53 to 2200 cm³/min and applications such as purging and fluid sampling. The FGM1190 covers a substantially wider flow range of 0.002 to 17600 l/h and is positioned as a general glass tube variable area flowmeter for system manufacturing, food, water treatment and chemical applications.
How is the FGM6100 different from the FAM3200?
Both are intended for small gas and liquid flows, but the FGM6100 uses a glass measuring tube for visual flow indication, while the FAM3200 is an armored variable area purgemeter with a stainless steel measuring tube and float. ABB positions the FGM6100 specifically as a glass tube flowmeter with flexibility and a minimum number of components.
