Thermal measuring instruments for the precise measuring of flow or mass flow rate in gaseous media

Thermal TA

Fixed and portable measurement of consumption quantity in compressed air and other clean gases; Measurement of laminar flow in clean rooms, under fan-filter-units; flow measurement in production facilities of the pharma-; food-processing- and semiconductor industry as well as flow-monitoring in glove boxes, isolators or sedimentation rate measurements in spray booths. Measurement of burner air and leakage flow; Monitoring of safety-relevant facilities – in aerospace as well as boats and ships.

Insertion probes

offer greater flexibility when used in pipes and ducts with larger diameters or in portable applications.

Measuring tubes

provide almost negligible measurement uncertainty when used in small pipe diameters.

Fixed evaluation units

for fixed evaluation of thermal flow probes TA and measuring tubes TA Di.

Portable evaluation units

for portable applications with TA probes

Software / Accessories

PC software for downloading data from handheld units or configuring evaluation units ...

How does a thermal mass flow sensor (hot-wire anemometer) work?

The measurement principle is based on heat transer between a heated sensor element and the flowing medium. An electrically heated wire transfers heat to the passing gas and cools down in the process. The change in electrical resistance is measured and converted into mass flow rate.

The advantage lies in the direct measurement of mass flow since no complex compensation for temperature and pressure is required. Unlike mechanical flow meters with moving parts, thermal systems operate without wear and are therefore particularly low-maintenance.

What types of designs are available for thermal flow measurement?

Insertion probes can be used flexibly thanks to their simple installation and can be used in pipes with diameters as small as 25 mm. Installation and removal are performed using probe guide pieces; in pressurized pipelines additionally with ball valves.

The TA10 models respond even to very low flow velocities and can be used reliably at extreme values of over 200 Nm/s. They are designed for operating pressures up to 50 bar and, depending on the model, cover temperature ranges from -20 to +240° C.

For smaller pipe diameters, inline sensors are used, which operate with inside diameters between 8 and 53.1 mm, measurement ranges from 0.04 to 1196 Nm³/h and extremely low measurement uncertainties. The temperature range here is also -20 to +240° C at pressures up to 50 bar. Custom solutions are available at any time.

Many models already include integrated transducers. Data can be transmitted via WLAN/WiFi, allowing analysis using any internet-enabled device. Additionally, interfaces such as two 4-20 mA analog outputs, media temperature output as well as bus systems like M-Bus or Modbus TCP are available.

What advantages does thermal flow measurement offer?

Thermal mass flow meters measure mass flow directly, eliminating the need for additional pressure or temperature sensors and significantly simplifying the measuring chain. This also increases the accuracy of the results.

The devices are highly sensitive to low flow velocities and reliably measure even the smallest gas volumes. Since they have no moving parts, they are wear-free, durable and require minimal maintenance. Their use as calorimetric flow meters highlights the versatility of the measuring method.

Furthermore, Höntzsch's flow sensors are approved for use in hazardous areas (ATEX, CSA). They can also be sterilized with hydrogen peroxide (H2O2) for example as part of CIP and SIP processes.

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What types of media can be used using thermal flow measurement?

Thermal measuring devices are particularly suitable for clean, dry and pure gases.

Air and compressed air - for consumption measurement, leak detection and energy management
Process and fuel gases - natural gas, city gas, propane (C3H8), butane (C4H10), methane (CH4)
Industrial gases - nitrogen (N2), carbon dioxide (CO2), oxygen (O2), argon (Ar), helium (He)
Specialty gases - sulfur hexafluoride (SF6) for leak testing, ethyne (C2H2) for welding applications
Biogenic gases - landfill gas and biogas for monitoring energy and environmental processes
Future energy sources - hydrogen (H2) for industrial and energy applications

The most common fields of application for thermal sensors are for example:

Consumption quantity measurement for energy monitoring, energy management and in facility operations
Fixed and portable consumption quantity measurement in air and different clean gases
Detection of leaks in process plants
Performance monitoring of compressors
Aeration air in wastewater treatment tanks/nitrification tanks
Measurement of very low flow velocities
Laminar flow applications in clean rooms, laboratories, under fan-filter-units, in production areas of the pharmaceutical (glove boxes); food-processing- and semiconductor industry (isolators)
Monitoring of settling velocity for example in the automotive industry (paint booths)
For high-precision gas mass flow proportional measurements such as in engine test benches, climatic chambers, combustion control and supply burner air
Aerospace, on ships and boats

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For which industries is thermal flow measurement suitable?

Thermal anemometers (also known as hot-wire anemometers) are used in a wide range of applications. They are particularly well-suited for portable and fixed consumption measurement of compressed air and other gases. They measure the standard flow velocity within the range of 0.08 to 200 Nm/s, the standard flow rate starting at 0.04 Nm³/h and the mass flow of the respective gas - with a fast response time of just one second.

Various interfaces are available for visualizing and processing the measurement results, for example for natural gas, propane, butane, LPG, compressed air or CDA. These include 4-20 mA, quantity pulse, M-Bus, Modbus, TCP, I/O-Link and Wi-Fi for wireless transmission.

Multigas applications and their areas of application

Thermal mass flow meters can be configured to measure various gases without requiring complex adjustments to the device.

With the latest sensor generations, the same device, optionally equipped with M-Bus, can be used in hazardous areas category 3G and 3D (zones 2 and 22) without requiring recalibration or return to the manufacturer. This means that a single base unit is sufficient, simplifying handling during operation and storage.

The ability to easily switch between gases allows use even in systems with varying requirements. In addition, additional gases can be integrated at any time as special characteristics that are based on a real-gas calibration in our in-house laboratory. If you're interested we are happy to assist you with any further questions.

热式质量流量计有哪些构造?

插入式探头易于安装，适用于内直径大于25 mm的管道。加装球阀和卡套时，可在加压管道中非常方便地插入或移除流量计。

TA10型号可精准测量极微小的质量流量，最大量程高达200Nm/s，是插入式热式质量流量计。

最高耐压可达50 bar
工作温度范围取决于版本和型号，介于 -20 °C 和 + 240 °C 之间。

管段式质量流量计可在内直径很小的管道中安装，用于长期式测量。

可测管道内直径范围为8 mm … 53.1 mm
测量范围为0,04 Nm³/h … 1196 Nm³/h
极小的测量不确定性
耐温范围-20 °C ... +240 °C
最高耐压可达50 bar

可按客户需求定制流量计

根据不同的型号可加装一体化变送器。还可以通过 WLAN/WiFi 接口从任何支持 Internet 的设备查看和传输数据。

可选其他接口，例如两个 4 … 20 mA 模拟输出信号、介质温度、各种总线接口(M-Bus、Modbus TCP)等。