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Our outstanding product is the VSM-3K with its huge measuring range of at least 1:3000 (!)

VSM-3K with measuring nozzle (left) and calorimetric sensor (right) VSM-3K, picture taken from a customer's catalogue

With this extremely large measuring range the VSM-3K is not only suited for measuring gas or compressed air consumption rates, as would be quite usual, but it can be used in order to perform a search for small or smallest leakages as well. This feature are built-in, so to say, so there is no need to modify anything in the line system prior to checking for possible leakages. Also in R&D the large measuring range of the VSM-3K makes it a unique and valuable measuring tool.

Clearly, with the use of a number of appropriate measuring nozzles, the scalability (total measuring range) of a standard VSM-02 is even more impressive. On the one hand it is possible to measure how many ml of air are moved by one puff from a cigarette, and on the other hand one can measure as well the daily or yearly consumption of giant assembly halls, for instance.

The VSM-3K has the same or better scalability, of course, but can do still a lot more than a standard VSM-02, especially in situations where the flow rate profile might change thouroughly and frequently.

Simply by not requiring to change the measuring nozzles and by not requiring to stop the gas supply during the time needed otherwise to install a different measuring nozzle, the VSM-3K saves a lot of time and money, for instance when used for leakage searches from time to time. Because the line system is held under full working pressure all the time, a quick leakage survey can take place whenever possible, e.g. during lunchtime breaks, and there is no need for tedious coordinations with the cost centers in order not to interfere with their work. They either work or don't. And if they don't work, you can see immediately whether there are any permanent leakages or not.

Measuring ranges:

0.5 inch nozzle 1 inch nozzle 2 inch nozzle
Line pressure 1 bar 6 bar 1 bar 6 bar 1 bar 6 bar
Volume flow
calibrated [l/min]
0.5 - 1530 0.5 - 3000 1.4 - 4300 1.4 - 8500 5.7 -17000 5.7 - 33000
2mm nozzle 4mm nozzle
Line pressure 1 bar 6 bar 1 bar 6 bar
Volume flow
calibrated [l/min]
3.2-48 6.3-95 14-210 27-410

Just like the VSM-02, the VSM-3K can be adapted to practically any given consumption situation by the use of different measuring nozzles. Customer specific nozzles are possible, diameters as required.

The extreme measuring span was reached by the integration of a calorimetric sensor for very low volume flow rates below the sensitivity threshold of the VSM-02.

Right: the ready-to-use assembled VSM-3K system in its stable transportation case VSM-3K in transportation case Calorimetric sensor Left: calorimetric sensor in patented mounting case

At very low gas speeds the calorimetric measuring principle is extremely sensitive. However, this sensitivity rapidly goes down at higher gas speeds and an early saturation limits measurements at still higher speeds. In combination with the measuring principle of the VSM-02, however, the resulting measuring device now has an extremely wide measuring range (measuring span). Already at ambient pressure a span of typically 1:3000 is reached, at higher operating pressures even more.

But that is not all. For the VSM-3K we used, of course, the existing sensors of the VSM-02 in order to minimize the notorious shortcomings of the calorimetric measuring principle, namely by performing an independent pressure and temperature compensation. It should be noted that most commercially available, stand-alone calorimetric mass flow measurement systems are, simply by their design, not capable of doing any similar corrections.

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USA version

The USA version comes by default with the units shown in the picture below (SCFM, PSI, °F etc.). With the included PC-software the device can be re-programmed to use metric units, if desired.

VSM-02 with imperial units  VSM-02 with metric units 
USA version  European version 

In general all newer VSM-02 devices can work with metric units as well as with units based on foot and pound. Therefore, users of the European version, too, can switch to the US unit system, if desired.

Tip: When examining very low consumption rates by watching the consumption counter, the use of the US unit system can be advantageous. This is due to the fact that 'cu ft' (cubic foot) is a much smaller basic unit than m³ (cubic metre). In the metric version the least significant digit of the consumption counter is 1 litre (=1/1000th m³), whereas it is only about 0.28 litres (=1/100th cu ft) in the US version. Mind you, however, that the included Windows software offers some better and more precise methods for examining very low consumption rates and flow profiles.

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