´
University of Applied Sciences Hamburg
The Milligascounter® for fermentation tests online
At the Hamburg University of Applied Sciences a novel volumetric gasometer has been developed.(Email: paul.scherer@haw-hamburg.de). The distribution is performed by the Dr. Ing. Ritter Apparatebau GmbH, Bochum (www.ritter.de) or by Bluesens GmbH (www.bluesens.de)
The Milligascounter® works according to the principle of a tilting box
The instrument is made primarily of transparent acrylic plastics. The basic principle is a little box with a partition and being open at two sides on the ground. Under the box (tilting box) through a whole (e.g. from a biogas reactor or an anaerobic bottle test) gas comes out and streams into in one chamber of the box until it moves up. Then gas streams out and the box turns to the other side. Again gas streams into the second chamber of the box, the box again moves up, by a jolt gas flows out. This movement repeats and a contact mechanism at the movable box counts the movements. The counts of movements give information about the measured gas volume.
Features
The original Milligascounter® is calibrated at three different flow rates and each instrument is certified for its linearity. The precision of the smallest version of the instrument is about 1 ml + 3% at 1ml/h or 1000 ml/h. The determined calibration factor converts automatically the counts on the LCD-display into ml. The chamber of the Milligascounter® has a height of 4 cm and it is filled by a special liquor. The LCD-counter contains a lithium-battery for longstanding operations (about 7 years). In contrast to the applied gasometers for fermentation tests or anaerobic fermentation tests, which are based on simple replacement of water (DIN 38414-S8 or ASTM 5210), the expense of the maintenance of this device is essential easy to do. VDI guidline 4630/4631.
In comparison to pressure gauges of closed fermentation bottles there is no pressure which might influence the biological processes. The pressure changes only between 5 and 7 mbar. The gas above the reservoir can be analysed simply by gas chromatography. You can monitor automatically up to 32 milligascounter® by one personal computer and evaluate kinetically the data by the software “Biochart”. The online version of the Milligascounter® is especially suitable for fermentation tests. The larger versions of the Milligascounter® can be applied up to 10-20 l fermentation reactors (8 ml/h-5000 ml/h flow rate of gas).
Summary:
· Measurement under non-pressurized conditions (5-7mbar)
· Miniaturized “stand alone instrument”(overall size 10x10x9cm height)
· Qualified for humid, variable gas-mixtures
· Longstanding operations without loosing gas (depending on the tube material)
· Simple optical monitoring of all functions with an electronic LCD-display and ml as unit
· Full transparency of the instrument
· up to 32 Milligascounter® could be connected to a personal computer by a special impulse
data logger (output 2 Volt for 1/10 sec)
The Milligascounter is calibrated at room temperature (21°C). A higher temperature needs a new calibration.
Scheme of the “Milligascounter®” to measure the biogas production of fermentation bottles or to measure the gas-production rate of co-digestion or other fermentations.
Contact: Paul.A.Scherer
Hamburg University of Applied Sciences, Lohbruegger Kirchstrasse 65, 21033 Hamburg-Bergedorf, Germany, Paul.Scherer@haw-hamburg.de