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Measuring volumetric flow by means of oscillation
KOBOLD offers their KOBOLD-DOG range of flowmeters that use the unique oscillation principle to measure dry or humid gases even in low pressure applications.
In this measuring procedure, a partial stream of the medium is led into the measuring cell by means of a bypass. In the measuring cell, the medium flows through a chamber with two flow channels. A gate allows the stream to flow through either the left or the right channel. The flow creates over-pressure on one side and under-pressure on the other. The difference in pressure directs the media stream to the other side. This results in the stream between the two sides oscillating, which sets the medium in the connecting channel into vibration. The frequency of the oscillation is directly proportional to the flow speed. A detector determines the oscillation in the connecting channel and converts it into an electrical signal. The signal is processed further in the downstream electronic unit and then displayed or output in another form.
The devices within the Kobold DOG flowmeter family are designed for tough industrial use. The Kobold DOG flowmeters are offered in flange or intermediate flange versions up to nominal widths DN 200 in stainless steel. This means that the equipment can be used for many different applications, such as compressed air, natural gas, biogas, fermentation gas, propane, hydrogen gas and many more. Approval by the European ATEX guideline and IECEx also means that explosive gas streams can be safely measured.
The oscillation system requires only a low feed pressure (in contrast to other measuring systems), and can also be used in biogas applications where measurement is otherwise extremely difficult. Generously-dimensioned channels mean that the measuring devices are less prone to dirt deposits. There are no moving parts in the media stream and therefore there is no wear.
The advantages are; reliable performance maintained over long lifetime; a high degree of measuring accuracy; not prone to dirt deposits; no wear and large measuring ranges.