Fox Thermal Instruments FT2A Specifications

Model

Thermal Mass
Flow Meter &
Temperature
Transmitter

Precision Mass Flow Measurement

Model FT2A Gas Mass Flow Meter
For Industrial & Wastewater
Applications

• Measures gas flow rate in SCFM,
NM3/HR, LBS/HR, KG/HR, & many

more

• Wide measurement range; 100:1
turndown typical

• Measures process gas temperature

• 4-20mA for flow rate & temperature;
pulse output for flow/total

• USB port to connect to a PC standard;
Modbus RTU (RS485), BACnet MS/
TP (RS485), Profibus-DP, DeviceNet or
Ethernet Modbus TCP

• Insertion and Inline models

• Welded, 316 SS sensor construction;
Hastelloy C276 optional

• Microprocessor based, field
programmable electronics

• On-board 2 line x 16 character, backlit
display with configuration panel to
view/set readings and parameters

• Free FT2A View ™ Software available

• NIST traceable calibration

• Low-end sensitivity for leak detection

• Negligible pressure drop

• No moving parts design

• FM (U.S.) & FMc (CANADIAN)
approved for Class I, II, III, Division
2, Groups A, B, C, D, E, F, G T4A
hazardous locations. NEMA 4X and CE
approved.

• EMC Certification to: EN 61326­1:2013

• LVD Certification to: EN 61010-1:2010

• EU Directive: 2014/68/EU

• Weld Testing: EN ISO 15614-1 and EN
ISO 9606-1, ASME B31.3

FOX THERMAL

399 RESERVATION ROAD
MARINA, CA 93933
PHONE: [phone]
FAX: [phone]
[e-mail]
www.foxthermal.com

An ON

I

CON Brand

FT2A

Fox Model FT2A Gas Mass Flow Meter & Temperature
Transmitter

The Fox Model FT2A measures gas ow rate in standard units without

the need for temperature or pressure compensation. It provides isolated

4-20mA and pulse outputs for ow rate, and a 4-20mA output for process

gas temperature. The pulse output is normally used for totalization.

With an on-board 2 line x 16 character, backlit display, operators can view

ow rate, total, elapsed time, process gas temperature, and alarms. The
display is also used in conjunction with the Conguration Panel to congure
ow meter settings, pulse output frequency scaling, pipe area, zero ow
cutoff, ow ltering (damping), display congurations, diagnostics and high

or low alarm limits.

The Model FT2A is available in both insertion and inline models. The insertion
meter is easily installed by drilling a ¾” hole in the pipe and welding on a

¾” NPT coupling. A Fox-supplied compression tting secures the probe in

place. The inline model is available in ¼-inch to 6-inch sizes and includes

built-in ow conditioners that eliminate the need for long, straight pipe runs.
The meter can be ordered with ange or NPT end connections.

Both models are supplied with 316 stainless steel wetted materials standard

or Hastelloy C-276 as an option (inline ow bodies also available in carbon

steel). A USB port to connect to a computer or laptop is standard; interface
options include Modbus RTU (RS485), BACnet MS/TP (RS485), Probus-DP,

DeviceNet or Ethernet Modbus TCP.

Fox has certied cleaning and bagging procedures for ow meters to be

used in oxygen applications.

100

10

1

110 100 1000 10,000

6"

.25"

.5"

.75"

1"

1.5"

2"

3"

4"

1.25"

2.5"

6"

4"4"

1000

100

10

1

110 100 1000 10,000

6"

.25"

.5"

.75"

1"

1.5"

2"

3"

4"

1.25"

2.5"

6"

3.3

THERMAL MASS TECHNOLOGY

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 sensor
elements are constructed of a reference grade platinum

NIST Traceable Factory Calibration

Fox calibrations are performed with NIST traceable ow
standards. Whether you require a straightforward air

calibration or a complex mixed gas calibration, our goal is
to achieve the highest accuracy and the fastest turnaround
time.

wire wound around ceramic mandrels that are inserted into
stainless steel or Hastelloy tubes.

The Fox Calibration Lab employs a wide range of gases,
gas mixtures, temperatures, pressures and line sizes to

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)

simulate actual uid and process conditions. This real-

world approach improves installed accuracy and minimizes
measurement uncertainty.

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 4-20mA signal.

PRESSURE DROP DIMENSIONS

Pressure Drop Charts for Inline Flow Meters

As seen in the charts below, pressure drop is negligible and energy
losses are minimal.

Meter Dimensional Drawings

The FT2A is available in many different
configurations. An example of the
local insertion and remote inline flange
configurations are shown below. To see more
configurations, visit our website at www.

foxthermal.com/literature/

Inches of Water

millibars

Local Insertion

(84)

1.50
(38.0)

1.40
(35)

7.12

(181)

SCFM

2x 3/4 inch NPT Female

FLOW

5.35
(136)

Input
Power

MODEL FT2A

Gas Mass Flowmeter & Temperature Transmitter

C
L

Signal
Wiring

“HH”

“LL”

Remote Insertion

3.3

2X 3/4” NPT,

FEMALE

SHIELDED, 100ft (30.48m) MAX

(84)

1.50
(38)

1.4
(35)

7.12
(181)

4.4

“HH”

(112)

2.0
(51)

4.5

(114)

“LL”

FLOW

CONDUIT,
3/4”, METAL

C
L

5.35
(136)

MODEL FT2A

Gas Mass Flowmeter & Temperature Transmitter

REMOTE CABLE, 5 CONDUCTOR,

NM3/hr

SIZING

Dimensions

Assuming there is no insulation or retractor, Fox
recommends the following probe lengths:

Pipe Size Probe Length

1.5" (40mm) to 6" (150mm) 6-inch

8" (200mm) to 12" (300mm) 9-inch

14" (350mm) to 18" (450mm) 12-inch

Use the equation on previous page for larger pipe sizes

Probe Lengths (LL) in inches(cm) =

6.0 (15.2) 9.0 (22.9) 12.0 (30.5)

15.0 (38.1) 18.0 (45.7) 24.0 (61.0)

30.0 (76.2) 36.0 (91.4)

Insertion Flow Meters: Probe diameter: ½”

Equation for selecting insertion ow meter probe length:

Probe length = ½ pipe ID (in inches) + 2” + thickness of
insulation (if any) + dimension of retractor (if supplied).
Round up to the next standard probe length available.

Contact Fox for longer probes.

Inline Flow Meter Dimensions

Pipe size L

0.25" 5.80 (147) 9.9 (251)

0.5" 12.0 (305) 9.9 (251)

0.75" 12.0 (305) 9.9 (251)
1" 12.0 (381) 9.9 (251)

1.25" 12.0 (305) 9.9 (251)

1.5" 12.0 (305) 9.9 (251)
2" 12.0 (305) 9.9 (251)

2.5" 18.0 (457) 10.0 (254)
3" 18.0 (457) 10.0 (254)
4" 18.0 (457) 10.5 (267)
6" 24.0 (610) 11.6 (295)

HH

Note: Dimensions are in inches (mm). For certified drawings,
consult factory or view at www.foxthermal.com/literature/

Approvals

CE: Approved

EMC Directive; 2004/108/EC

Electrical Equipment for Measurement, Control, and Lab

Use: EN61326-1:2008
Low Voltage Directive (LVD): 2006/95/EC
Product Safety Testing: EN 61010-1: 2010

Pressure Equipment Directive: 97/23/EC

Weld Testing: EN ISO 15614-1 and EN ISO 9606-1, ASME
B31.3

FM and FMc: Approved

Class I, II, III, Division 2, Groups A, B, C, D, E, F, G, T4A
hazardous locations.
NEMA 4X Approved

NOTE! The EU Pressure Equipment Directive (PED) requires
that the minimum ambient and uid temperature rating for
carbon steel ow bodies not be below -29C.

Try the Fox thermal online congurator

Precision Mass Flow Measurement

An ON

I

CON Brand

399 RESERVATION ROAD

MARINA, CA 93933

PHONE: [phone]

FAX: [phone]

[e-mail]

www.foxthermal.com

to request a quote for a meter suited for your

APPROVALS & SPECIFICATIONS

Performance Specs

Flow Accuracy:

Inline meter: ± 1% of reading ± 0.2% of full scale.
Insertion meter: ± 1% of reading ± 0.2% of full scale.

Straight, unobstructed pipe requirement:

Inline: 8 diameters upstream; 4 downstream.
Insertion: 15 diameters upstream; 10 downstream.
Insertion (¼” size): 6” (152mm) upstream &
downstream

Flow Repeatability: ± 0.2% of full scale

Flow Response Time: 0.9 seconds (one time constant)

Temperature Accuracy:

± 1.8° F (± 1.0° C) over -40 to 250° F (-40 to 121° C);
± 3.6° F (± 2.0° C) over 250 to 650° F (121 to 343° C).
Minimum velocity 60 SFPM.

specic process conditions.

www.foxthermal.com

SPECIFICATIONS

Operating Specs

Units of Measurement (field-selectable):

SCFM, SCFH, NMPS, NM3/M, NM3/H, NM3/D, NLPS,

NLPM, NLPH, MCFD, MSCFD, SCFD, MMSCFD, MMSCFM,
SMPS, SM3/D, SM3/H, SM3/M, LB/S, LB/M, LB/H, LB/D,
KG/S, KG/M, KG/H, SLPM, SFPM, MT/H

Flow Rates for Insertion Flow Meters:

15 to 60,000 SFPM (0.07 to 280 NMPS) - Air at 70°F
(20°C) & 1 ATM

Turndown: up to 1000:1; 100:1 typical

To determine if an insertion ow meter will operate
properly, divide the maximum ow rate by the pipe area.

The application is acceptable if the velocity is within the
velocity range above.

Typical Flow Ranges for Insertion Flow Meters

Pipe size SCFM MSCFD NM3/hr

1.5" (40mm) 0 - 840 0 - 1,220 0 - 1,325
2" (50mm) 0 - 1,400 0 - 2,020 0 - 2,210

2.5” (63mm) 0 - 2,000 0 - 2,880 0 - 3,150
3" (80mm) 0 - 3,100 0 - 4,440 0 - 4,890

4” (100mm) 0 - 5,300 0 - 7,650 0 - 8,360
6" (150mm) 0 - 12,000 0 - 17,340 0 - 18,930
8" (200mm) 0 - 20,840 0 - 30,020 0 - 32,870

10” (250mm) 0 - 32,800 0 - 47,250 0 - 51,740

12" (300mm) 0 - 46,600 0 - 67,180 0 - 73,500

Flow Ranges for Inline Flow Meters

Size

0.25" 0 - 7.5 0 - 10.8 0 - 11.8

0.5" 0 - 125 0 - 180 0 - 200

0.75" 0 - 220 0 - 320 0 - 350
1" 0 - 360 0 - 520 0 - 570

1.25" 0 - 625 0 - 900 0 - 990

1.5" 0 - 840 0 - 1,220 0 - 1,325
2" 0 - 1,400 0 - 2,020 0 - 2,210

2.5" 0 - 2,000 0 - 2,880 0 - 3,150
3" 0 - 3,100 0 - 4,440 0 - 4,890
4" 0 - 5,300 0 - 7,650 0 -8,360
6" 0 - 12,000 0 - 17,340 0 - 18,930

Note: Standard conditions of air at 70°F and one
atmosphere. Consult factory for other gases and for flow
ranges above and below those listed above.

Gas Pressure (maximum):
Insertion: 500 psig (34.5 barg)

316 SS inline with NPT ends: 500 psig (34.5 barg)
316 SS inline with 150 lb. flanges: 230 psig (16 barg)
CS inline with NPT ends: 300 psig (20.1 barg)
CS inline with 150 lb. flanges: 285 psig (19.7 barg)
Retractor: 125 psig (8.6 barg)
High pressure retractor: NPT 600 psig (41.4 barg), ANSI

150 flange & ANSI 300 flange, no valve supplied.

Notes:

• Check with factory for higher pressure options.

• When teflon ferrule option ordered, gas pressure is
60psig (4.1 barg) maximum.

• Pressure ratings stated for temperature of 100°F
(38°C).

SCFM MSCFD NM3/hr

Relative Humidity: 90% RH maximum; non-condensing
Temperature:

Std sensor: -40 to 250°F (-40 to 121°C)

HT Sensor: -40 to 650°F (-40 to 343°C)

Enclosure: -40 to 158°F (-40 to 70°C) DC Power*

-4 to 158˚F (-20 to 70˚C) AC Power
*Note: Display dims below -4˚F (-20˚C); function returns

once temperature rises again.

Remote sensor junction box ambient temperature: -40 to

212˚F (-40 to 100˚C)

Input Power (without the Anybus serial communication

option):
24VDC

—

(±10%), 0.4 Amps (standard DC Power)

– – –

100 to 240VAC ~(+10%/-15%), 50-60Hz, 0.2 Amps (with
AC power option)

Input Power (with Anybus serial communication option):

24VDC

—

±10%), 0.7 Amps (standard DC Power)

– – –

(

100 to 240VAC~(+10%/-15%), 50-60Hz, 0.2 Amps (with
AC power option)
Note: Fluctuations of AC and DC power supply are not
to exceed ±10% of rating.

Class I Equipment (Electrical Grounding Required for

Safety).
Installation (Over-voltage) Category II for transient over­voltages.

Outputs:

Two isolated 4-20mA outputs (output one is for ow
rate & output two is programmable for ow rate or

temperature); fault indication per NAMUR NE43.
Isolated pulse output 0 to 100Hz, 5 to 24 volts p/p for

ow (the pulse output can be used as an isolated solid

state output for alarms); 20mA max.

Serial Communication:

USB connector for connecting to a laptop or computer
is standard; free PC-based software tool - FT2A View™ ­provides complete conguration, remote process moni­toring and data logging functions.

Optional isolated communication outputs: RS485-

Modbus, BACnet MS/TP, Probus-DP, DeviceNet or

Ethernet Modbus TCP.

4-20mA Loop Verication:

Simulation mode used to align 4-20mA output with the
input to customer’s PLC/DCS.

Physical Specs

Sensor Material:

316 stainless steel standard; Hastelloy C276 optional

Inline Flow Body Material:

316 Stainless Steel ow bodies standard; Optional A106
Grade B carbon steel ow bodies and A105 anges.

Enclosure:

NEMA 4X, aluminum, dual conduit entries with ¾” NPT or
optional M20 x 1.5mm.

Remote Sensor Cable:

5-conductor, 18 AWG, twisted, shielded, 100 feet
maximum.

Retractor Assemblies:

Packing gland assembly: 125 psig (8.6 barg ) max.

High pressure (crank) retractor: NPT 600 psig (41.4 barg),

ANSI 150 ange & ANSI 300 ange, no valve supplied.

FT2A Rev. N