FOX FT1 - Flow Meter Thermal Mass Flow Meter and Temperature Transmitter

The Fox DDC-Sensor™ is a new state-of-the-art sensor technology used in the Fox Model FT1 Thermal Gas Flow Meter. The DDC-Sensor™, a Direct Digitally Controlled sensor, is unlike other thermal flow sensors available on the market.

Instead of using traditional analog circuitry, the DDC-Sensor™ is interfaced directly to the FT1 microprocessor for more speed and programmability. The DDC-Sensor™ accurately responds to changes in process variables (gas flow rate, pressure, and temperature) to determine mass flow rate, totalized flow, and temperature.

Fox’s DDC-Sensor™ provides a technology platform for calculating accurate gas correlations. The FT1 correlation algorithm allows the meter to be calibrated on a single gas in the factory while providing the user the ability to select other gases in the Gas-SelectX™ menu. Fox’s Model FT1 with its DDC-Sensor™ and advanced correlation algorithm provides an accurate, multi-gas-capable thermal gas flow meter.

Gas-SelectX™ Gas Selection Menu

Many customers need a fast solution to their monitoring needs. For these cases, FOX has developed the Gas-SelectX™ calibration gas menu feature for the Model FT1 flowmeter. Gas-SelectX™ allows the user to choose from a menu of several common gases or gas mixtures for their application. Available gases are Air, Argon, Carbon Dioxide, Methane, Natural Gas, Nitrogen, Methane/Carbon Dioxide/ Nitrogen Mixes (more gases & mixtures available soon).

The user can program the percentages of methane, carbon dioxide, and nitrogen to achieve the perfect mix for their application. The meter’s proprietary algorithm allows the user to switch the calibration gas in the field, as needed. Whether you need to measure natural gas or air, CO2 or digester gas, the FT1 brings these options and more to the user with a quick push of a button.

Gases and gas mixes available in the Gas-SelectX™ feature include:

• Air
• Argon
• Carbon Dioxide
• Methane
• Natural Gas*
• Nitrogen
• Methane/Carbon Dioxide/Nitrogen mixes

 
*Natural gas refers to pipeline-quality dry natural gas, whereas naturally occurring gas from oil fields constitutes a special mixed gas calibration. Contact Fox for further information.
The methane / nitrogen / carbon dioxide mixes are programmable in 1% increments:

• Methane 0 - 100%
• Carbon Dioxide 0 - 100%
• Nitrogen 0 - 100%

Fast and Flexible Gas Flow Measurement

Theory of Operation

Fox Thermal Flow Meters use a constant temperature differential (constant Δ T) technology to measure mass flow rate of air and gases. The thermal mass flow sensor consists of two Resistance Temperature Detectors (RTD’s).

The Reference RTD measures the gas temperature. The instrument electronics heat the mass flow sensor, or heated element, to a constant temperature differential (constant Δ T) above the gas temperature and measures the cooling effect of the gas flow. The electrical power required to maintain a constant temperature differential is directly proportional to the gas mass flow rate. The microprocessor linearizes this signal to deliver a linear 4 to 20 mA signal.

Fox Model FT1 Thermal Gas Mass Flow Meter Features

The Fox Model FT1 measures gas flow rate in standard units without the need for temperature or pressure compensation. It provides an isolated 4 to 20mA output and a selection of pulse, RS485 Modbus RTU, or BACnet MS/TP for a second output.

With an optional on-board 2-line x 16-character, backlit display, operators can view flow rate, total, elapsed time, process gas temperature, and alarms. The display is also used in conjunction with the Configuration Panel to access flow meter settings, such as 4 to 20mA and pulse output scaling, pipe diameter, zero flow cutoff, flow filtering (damping), display options, and high or low alarm limits.

The Model FT1 has an insertion probe and is easily installed by drilling a ¾” hole in the pipe and welding on a ¾” NPT coupling. A Fox-supplied compression fitting secures the probe in place. It is supplied with 316 stainless steel wetted materials standard. A USB port to connect to a computer or laptop is standard; interface options include RS485 Modbus RTU and BACnet MS/TP.

Fox has certified cleaning and bagging procedures for flow meters to be used in oxygen applications.

Advanced Features

Suitable for harsh and hazardous environments, the instrument features:

• Advanced DDC-Sensor™
• Gas-SelectX™ technology
• Rotatable probe: allows ±180 degree swivel
• FM/FMc, ATEX, IECEx approvals (pending). CE mark.
• 10-30VDC power input, standard
• NIST-traceable calibration
• Free FT1 View™ Software
• High and low alarm limits
• Wetted materials are all welded, 316 stainless steel

Perfect for commercial and industrial applications, the Model FT1 is the latest instrument offered in the FOX product line.

Zero CAL-CHECK

For customers that need a quick and easy way to verify the calibration of the meter in the field, the Model FT1 offers the Zero CAL-CHECK™ feature. This feature can be accessed and run through the meter’s optional display configuration panel or the FT1 View™ Software. The test takes less than 5 minutes to run and produces a pass/fail result at the conclusion of the test. A fail result may indicate either a dirty sensor or the need to recalibrate.

If the Zero CAL-CHECK™ test is performed using the FT1 View™ software, a Calibration Validation Certificate can be produced at the conclusion of the test. The certificate will show the date and time of the test along with meter data such as firmware version and meter serial number. This in situ calibration validation helps operators comply with environmental mandates and eliminates the cost and inconvenience of annual factory calibration.