What is different from other technologies?
Comparison of alcohol meter with other technologies
Definition of measurement items
Firstly, understanding the definition of each word is very important. Below is the introduction of each units. The alcohol meter uses the following expressions on display and printout:
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Density: Density at 20 degree Celsius
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S.G(20/20): Specific gravity at 20 degree Celsius
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Alcohol: Alcohol vol% at 20 degree Celsius (OIML table)
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Alcohol(A): Alcohol vol% at 20 degree Celsius (AOAC table)
Definition of measurement items
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Alcohol concentration (Vol%) - Unit of volume percentage of ethanol and water at 20 degree. Alcohol meter equips conversion table between the ethanol percentage and density value. This unit is used in quality control of alcohol drinks.
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Density - Mass (e.g. gram) per unit volume (e.g. cm3).
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Specific gravity (SG)(relative density) - SG is the ratio of mass between a substance and reference standard.
Method comparison to measure alcohol concentration
Cleanness
Meas. of flow Initial Running
Usability Accuracy Calibration Time Channel Cost Cost
Hydrometer Difficult Low Difficult Long Moderate Low Low
Infrared method Difficult Middle Difficult Short Required High Low
Gas
chromatography Difficult Middle Difficult Long Required High High
Distillation
plus alcohol meter Easy Good Easy Short Moderate Middle Low
Hydrometer
Infrared Method
The price on the market is reasonable, however, cost of annual calibration at third party is expensive. Operator has to take care of the operation since it is made of glassware. When this method is used, large volume of sample needs to be prepared whilst operator has to wait until temperature reaches the specific testing temperature. The human error depending on operator's experience is large, so it is very difficult to get reliable results everyday.
This method is the latest technology. However, the price is still not reasonable for general alcoholic manufacturers and some countries don't approve it as an official method. This method has gap of accuracy between test result and theoretical value when alcohol concentration is high. Since operators needs to prepare calibration standard, it is not easy works for unexperienced operators.
Gas chromatography
Distillation plus
Alcohol Meter
This method is efficient when you prefer to get several elements results from one sample. However, operator has to prepare carrier gas and do calibration with standard solutions and the initial cost is expensive. The operation is also not easy for general operators in alcoholic manufactures.
This is a traditional method and the result is most reliable. In many countries, this process is adopted to method of national regulation. Before measurement of alcohol concentration by alcohol meter (density meter), the process of distillation where the organic substance like sugar is removed from the sample solution. After distillation the mixed solvent (only pure water and alcohol) is tested by alcohol meter. The biggest advantages of alcohol meter ALM-155 is the ability to measure any colored sample and process high viscous sample.
Principle of alcohol meter
(oscillation method density meter)
Imagine the model at right, where a weight is attached to the end of a bar. If you flick the weight with your finger, the weight begins to oscillate. You can see that it oscillates more slowly with more weight, and faster with less weight. This is because the weight will vibrate on the oscillation period specific to a substance in proportion to the mass of the weight.
Advantage/Disadvantage of alcohol meter
Advantage
Disadvantage
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Only small sample volume is required
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Digital display leads to no misreading
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Short measurement time
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Low running cost
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Easy-to-use and easy-to-clean for all operators
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Compliance with national standard in most of countries
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Easy to transfer result to your PC
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Any colored sample is measurable
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High viscous sample is measurable
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For alcohol measurement, distillation process need because it is best preparation to measure alcohol concentration precisely.
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Initial cost is higher compared to hydrometer
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Power supply is required