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Gas Flow Meter Makes Sampling Simple with Compact 2 Series

9 Oct 2023  |
The Compact 2 is a gas flow meter based on the thermal principle. This means that this unit suitable for many gases in a range from 0-10 mln/min to 450 ln/min. The unit can be powered with a single AA battery, USB or with 24 vdc, Configuration is done over the touch screen. The unit is used a lot for flow verification and in the analytical science.

Gas sampling is the first step in the collection of data that guards process variables, monitors emissions and verifies that processes are running consistently. We notice a growing demand for regular interval sampling that needs to be consistent and reliable. Sample specialists have discovered the simplicity and economics of the Vögtlin red-y compact 2 series mass flow meters with optional integrated alarm module.

Digital mass flow meter of the red-y compact 2 series with manual control valve

Making sampling simple

In the following application, users make use of the compact alarm module expansion that gives them 3 alarm points, 2 I/O inputs and an external power supply. The alarm module replaces the battery compartment and is integrated in the red-y compact 2 meter at the back with a 3 meter, 12 conduct wire for all the connections.

Gas sampling application with two gas flow meters

The diagram for the sample taking system only requires a few external components. The compact 2 alarm unit is integrated in the compact 2 flow meter and all settings are programmed in the Compact 2 alarm module through the touch screen. The solenoid valves opens up and fills the sample bag with a predefined quantity of gas. Once the flow meter totalizer reaches that value, it closes the solenoid and starts a timer to for the next sample.

The compact 2 is the standard GCR model with an integrated needle valve. This needle valve is selected based on your process conditions and with that valve you set the sample rate you want. For instance 100 mln/min.

In the analytical world the red-y compact 2 meter is used as the heart of a reliable automatic, low cost gas sample taking device.

Emission or environment measurements often demand periodic samples of a fixed amount of gas andcollect these in a container or sample bag. For example every hour a 100 scc sample. The red-y compact 2 meter with its optional smart alarm module has the complete solution without the need of any PLC to control the process.

The system runs on 24 Vdc. The compact 2 alarm module has 3 alarm points that are individually programmable for different alarm functions, such as totalizer, window, high and low alarm. It also makes use of the timer functions and the ability to reset the alarms and totalizer with an I/O input on the alarm module. See the full description on

Many of the users of these systems obtain a battery powered high accuracy red-y compact 2 meter to verify if the flow meter in the field is working properly or if it needs calibration or cleaning. The red-y compact 2 has a big internal diameter flow channel, has a low pressure drop, is temperature compensated and measures the mass flow, independent of changes in pressure and temperature.


It is impossible to describe all the applications in which these types of flow meters are used, but if you see a VA meter for gas and you want to improve a process, talk to the experienced Vögtlin engineers and they will be pleased to help you to find a solution.

Find out more about the red-y compact 2 meter, the company and their other products on

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