Thermal Mass Flow Meter

Based on the sophisticated anemometric theory, the thermal mass flow meter operates on the gas velocity measured by the heat release of a constant-temperature platinum sensing element without using any external pressure inputs.

In this durable thermal dispersion mass flow meter construction, there are no moving parts used, resulting in a reliable mass flow meter device that is capable of generating virtually no pressure drop in your industrial distribution piping network.

Being designed for safe use, our explosion-proof thermal mass flow meter works perfectly in flammable conditions, which makes it an effective natural gas thermal mass flow meter or a utility sub-metering line detector.

Designed as a reliable digital thermal mass flow meter, the device generates an automatic 4–20 mA output setting, becoming a reliable mass flow meter measuring device.

• Media: Air, Oxygen, Nitrogen, Argon, Hydrogen, Natural Gas, Butane, Compressed Air, CO₂, Ammonia, Ethane, Helium, Methane
• Flow Range: 0 to 2500 CFM
• Operating Temperature: -40°C to 150°C
• Maximum Operating Pressure: 10 Bar
• Installation: Horizontal or Vertical
• Pressure Drop: Very Low

The Two Sensors

Inside the pipe, the meter sticks two small temperature probes out into the gas stream. One probe simply measures the actual temperature of the gas. The other probe is artificially heated so that it stays exactly 10°C hotter than the gas.

The Wind-Chill Effect

As the gas starts flowing through the pipe, it rushes past the heated probe. Just like a cool breeze on a hot summer day, the moving gas carries heat away and cools the hot probe down.

Calculating the Dynamics

The faster the gas is moving, or the denser the gas is (meaning more molecules are passing by), the faster the hot probe loses its heat.

Powering Up to Balance

The meter’s smart internal computer notices the probe is cooling down. To keep it exactly 10°C hotter than the gas, the computer pumps extra electrical current into the probe to heat it back up.

The Final Measurement

The computer of the meter determines the accurate temperature differential between the heated probe and the unheated reference probe. Since fast-moving gas takes more heat energy with it, there will be a lower temperature differential between the two probes. This temperature differential is accurately measured by the meter and converted into an accurate value of the amount of gas flowing in your pipe.

Mounting & Sizes

• Inline Sizes: DN15, DN20, DN25, DN40, DN80, DN100, DN150, DN200
• Insertion Sizes: DN50 to DN2000 probes
• Flow Ranges: 0 to 500 SM3/HR up to 2500 CFM

End Connections

• Threaded: Male/Female BSP, NPT
• Flanged: DIN, ANSI (PN16, PN40, PN100, Class 150, 300, 600 RF)
• Sanitary: Tri-Clamp (TC)

Materials

• Body: SS304, SS316 stainless steel
• Sensor: Platinum Winding in SS316L sheath
• Enclosure: Die-cast Aluminum

Gas Calibration

• Utilities: Compressed Air, Nitrogen, Argon, Helium, CO2, Hydrogen, Ammonia
• Fuel & Biogases: Natural Gas (PNG), LPG, Biogas, Digester Gas
• Oxidizers: Cleaned/Degreased Oxygen gas

Electronics & Power

• Power Supply: 24 VDC Isolated, 230 VAC, 110 VAC
• Display: 12×2 LCD screen with built-in totalizer
• Safety: Flameproof/Explosion-proof enclosure (Gas Groups IIA, IIB)

Inputs/Outputs

• Analog: 4-20mA (4-wire), 3.5-10V
• Digital: RS485/RS232 Modbus RTU
• Relays: Pulse output, High/Low alarm contacts
• Add-ons: Data logger PC software, external dot matrix printer

Direct Mass Flow Measurement : The thermal mass flow meter performs direct mass flow measurement of gases, thus avoiding the necessity of compensation for temperature and pressure in many cases.

Low Maintenance: Since the meter does not have any mechanical components in the sensing unit, it needs little maintenance and contributes to reducing wear and tear.

Suitable for Hazardous Locations: Flameproof versions of the meter are available for installation in hazardous locations where flammable gases like methane, biogas, natural gas, LPG, and compressed air could be present.

Measurement of Wide Range of Gas Flows: With its high turndown ratio, the meter is capable of measuring a wide range of gas flows from small to large ones.