Marmonix MTF-4500 Threaded Thermal Gas Mass Flow Meter

The Marmonix MTF-4500 thermal mass probe flow meter measures gas mass or standard-volume flow from 0.5 to 100 Nm/s for gases except acetylene. It uses two platinum resistance sensors and constant-differential-temperature thermal dispersion, so no temperature or pressure compensation is needed in principle. This page and its specification table cover both the pipe version (DN10–DN2000, ±1% of reading) and the insertion version (DN80–DN4000, ±2.5% of reading), with pulse and 4–20 mA output plus RS485 or HART on an IP65 transmitter. Browse all Marmonix flow meters, or see the MTF-4200 insertion thermal mass flow meter for large ducts.

Thread Thermal Mass Probe Flow meter MTF-4500

Thermal gas mass flow meter is designed on the basis of thermal dispersion, and adopts method of constant differential temperature to measuring gas flow. It has advantages of small size, easy installation, high reliability and high accuracy, etc.
The meter contains two platinum resistance temperature sensors. The thermal principle operates by monitoring the cooling effect of a gas stream as it passes over a heated sensor. Gas flowing through the sensing section passes over two sensors one of which is used conventionally as a temperature sensor, whilst the other is used as a heater. The temperature sensor monitors the actual process values whilst the heater is maintained at a constant differential temperature above this by varying the power consumed by the sensor. The greater the gas velocity, the greater the cooling effect and power required to maintain the differential temperature. The measured heater power is therefore a measure of the gas mass flow rate.

Thread Thermal Mass Probe Flow meter MTF-4500 Features

The MTF-4500 offers:

• Measuring the mass flow or volume flow of gas
• Do not need to do temperature and pressure compensation in principle with accurate measurement and easy operation
• Wide range: 0.5Nm/s~100Nm/s for gas. The meter also can be used for gas leak detection
• Good vibration resistance and long service life. No moving parts and pressure sensor in transducer, no vibration influence on the measurement accuracy.
• Easy installation and maintenance. If the conditions on site are permissible, the meter can achieve a hot-tapped installation and maintenance. (Special order of custom-made)
• Digital design, high accuracy and stability
• Configuring with RS485 or HART interface to realize factory automation and integration

Thread Thermal Mass Probe Flow meter MTF-4500 Specifications:

How thermal mass probe flow meters are used on plant gas lines

In a typical plant, compressed air, nitrogen or fuel gas is shared by several users, and the utility or energy team wants a mass-flow figure per line to allocate consumption and spot losses.

A thermal-dispersion probe carries two resistance-temperature sensors: one reads the gas temperature, and the other is held a fixed temperature difference above it by its heater power. Faster gas cools the heated sensor more, so the power needed tracks mass flow directly. ASME MFC-21.2 is the standard for measuring fluid flow with thermal dispersion mass flowmeters of this kind.

In a typical installation, the probe sits in a straight run of the line, the 4–20 mA or RS485 signal goes to the control or energy-monitoring system, and the totalizer and velocity readings show use by shift. The datasheet also lists gas leak detection as an application.

Questions about the MTF-4500 thermal mass probe flow meter

Which gases can the MTF-4500 measure?

The MTF-4500 measures mass or standard-volume flow for gases except acetylene, over 0.5–100 Nm/s referenced to 20 ℃ and 101.33 kPa. The sensor housing is SS304 or SS316, and the sensor is rated from −40 ℃ to +220 ℃.

Does the MTF-4500 need temperature and pressure compensation?

No, in principle the MTF-4500 does not need separate temperature and pressure compensation, because constant-differential-temperature thermal dispersion responds to mass flow directly. Its published response time is 1 s and it has no moving parts.

What outputs and power options does the MTF-4500 have?

The MTF-4500 gives isolated pulse and 4–20 mA output (maximum load 500 Ω), RS485 or HART communication, and 1–2 normally open relay alarms rated 10 A/220 V AC or 5 A/30 V DC. The compact type runs on 24 VDC or 220 VAC (≤18 W) and the remote type on 220 VAC (≤19 W).