Our most versatile model for any mass flow measurement need

Insertion Probe Thermal Mass Flow Meter Features

• Versatile solution for liquid or gas measurement

• Multi-point flow measurement available

• Repeatable rates within +- .2%

• 100:1 turndown range (1000:1 Application dependent)

Contact Thermal Instrument Co.

The Thermal Mass Probe Flow meter is inserted directly into the flow stream to measure the flow rate of gases, liquids, or slurries in stacks, irregularly shaped lines, and process ducts.  Unlike other probe flow meters, we offer a model that has no apertures that can be clogged with particles or distorted by wear. Our sensors are enclosed in a sealed tube which can be inserted or removed through a gate valve or a packing gland while conduit is in use. We also offer a mechanical retractor if required for your application. Our probes are manufactured using 316 SS as a standard, but corrosion resistant materials such as Hastelloy C, Monel, Inconel, Tantalum, and Carpenter 20 are also available.  In addition, our Thermal Mass Flow Meters are available in a variety of protective coatings including: Carbide, Fluorocarbon , Teflon, and Sulfinert.

Why are our flow meters so reliable and accurate?

Our Thermal Mass Flow Meters operate using a constant temperature system that employs two RTD sensors; one for sensing temperature, and one for sensing flow. The sensor is heated to a precise temperature above that of the fluid passing by. The Fluid conducts heat off the sensor in direct proportion to the mass flow rate. The temperature is used to set the heat on the flow sensor and correct for changes in the fluid temperature.

Enhanced Capabilities available with our Dual-Tip Probe (Model 62-9DT):Thermal Instrument Model 62-9DT Mass Flow Meter utilizing dual tip design for measuring high temperatures, flow rates, and can be inserted into line sizes as small as 1.5". Can accurately measure gases with temperatures up to 500 Fahrenheit.

We have increased our capabilities of our Model 62 insertion probe. This unit can now be installed in line sizes as small as 1 1/2" in diameter. Some of the features are:

  • High Gas Flow Rates
  • High Temperature Range
  • High Pressure Capabilities
  • Smaller line size capability (See Specification Chart Below)
  • 1000:1 Turndown Range Available


Multi-Point Capabilitity for Large Duct, Pipe, and Stack Gas Measurements - Part # 62-9MP

Our Model # 62-9MP Insertion Probe is the perfect solution for large ducts, pipes, or stacks where air or gas measurement is required. The Thermal Instrument multi-point probe allows for up (6) flow measurement locations across a pipe, duct, or stack utilizing our thermal mass technology. The flow is measured at different points across the insertion probe and then that flow information is averaged out and sent as one average flow to the electronic transmitter. With built in alarm capability your operator will even know when an issue has occurred and the flow has been disrupted or altered in any way. This is also a great instrument when your application has non-laminar flow, or turbulent flow, in large ducts, pipes, or stacks. With the ability to take multiple flow measurement points, our flow meter can take into effect all the different flow profiles and then transmit that data so that it can be used to effectively manage a process. We still encourage a flow profile analysis be performed in order to ensure that the best locations are chosen for flow measurement.

Dimensional Drawings

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Insertion Flow Probe Meter Specification Chart

Probe Specifications
Model # 62-9
Model # 62-9DT
Pipe / Line Size:
2½” SCH 40 to Unlimited
1½” SCH 40 to Unlimited
Flow Measuring Capability:
40 to 15,000 SFPM
30 to 86,000 SFPM
.01 to 15 Feet per Second
Temperature Range:
-20 to 350
-20 to 600
-28 to 162
-28 to 315
  Integral to the Flow Transducer
Accuracy: +/- .50% of Full Scale, [or 2.0% of reading whichever is better. Full Scale over the calibrated range. [Process fluid temperature span +/- 50°F] Remote to 4000 ft., Wall or Frame mount
Repeatability: +/- 0.2 % of Rate Signal Cable for Remote Design: 18 gauge, 2 pair with cable shield. Maximum distance, 4000 ft.
Gases: 1 to 2 sec. Typical Base Model: = 9500
Liquids: Less than 500ms  
Pressure Rating: Electronics Mounting:
0 - 1200 psig (Std) I = Integral Mount
0 - 10000 psig Dependent on meter size R = Remote Mount
  F = Fluid
Flow Rates: G = Gas
Gas: 40 to 86,000 SFPM L = Liquid
Liquid: .02 to 20 FPS  
Note: maximum determined by pipe capacity  
Flow Range: 100:1 Std. Multiple ranges available Material:
  316SS = STD
Calibrated Temperature Range: Corrosion Resistant Materials available by request: Hastelloy C, Monel, Inconel, Tantalum, and Carpenter 20
Gas: -20 F to 350 F (-28°C to 162°C )STD. Available Coatings: Carbide, Fluorocarbon , Teflon, and Sulfinert
[-20°F to 600°F] (-28°C to 315°C) Optional) Process Connection:
Liquid: -20F to 350F (-28°C to 162°C ) STD. PG = Packing Gland (Std.)
[ -20°F to 500°F](-28°C to 260°C) Optional FLG-150 =150# RF Flange (Std.Van stone)
  TC = Triclover
Wetted Materials: 316SS (STD). Consult the factory for other material requirements FLG-Other = Consult Factory
  Other = Consult Factory
Connections: Flange, Packing Gland, Triclover, Hot Tap  
Calibration Temperature Capability: -20°F to 600°F(-29°C to 315°C) 24 = 22-26 VDC, 1 AMP. 4 WIRE
  120 = 120VAC, 1/2 AMP, 50/60 HZ (STD.)
16 BIT A/D  
  Output Signals:
Displays: Bright LED 2 Line 8 digit (Select One**)
Capable of displaying Current Flowrate and Total Flow (Optional) 0/5 = 0-5 VDC**
  0/10 = 0-10 VDC**
Communicator: 4/20 = 4-20 mADC** into 750 ohms, Isolated std, Self Powered
Interface: RS-232 via Ribbon Connector 4/20T = Opt Process Fluid Temp. 4-20mA Self Powered
Baud Rate: 9600 Other = Consult Factory
Filter Factor  
Flow Full Scale Display: (Optional)
Flow Rate Decimal Point ND = No Display
Flow Totalizer Decimal Point D = Flowrate Display, 8 Digit
Flow Totalizer Flowrate Ratio 8T = Totalizer
  D/8T = Flowrate and Total Display, 8 digit
120/240 vat, 50/60 Hz. Signal Cable for Remote Design: SC25 = 25 FT Supplied with remote configuration
24VDC, 1 Amp (Factory Set)  
Electrical Connections:3/4” FNPT Power & Signal  
Enclosure: Cast Aluminum, Epoxy Painted  
Environmental Ratings:  
Housing: Explosion Proof, Class 1, Div. 1, Groups, B, C D  
Weatherproof: Nema 4  
Ambient Temperature: -25 to 60 C (-13 to 140 F)  
Storage Temperature: -40 to 70 C ( -40 to 158F )