In this blog entry we would like to show you how to calibrate and check the measurement accuracy of the ALM-155 Alcohol Meter. We hope you find it useful!
1. Do you need to calibrate? Check the measurement accuracy to find out!
Before starting your day’s measurements, we recommend to check the accuracy of the ALM-155 by measuring a sample of pure water and confirming that the result is 0.00±0.10vol%. If you left the tubing and cell to soak in ethanol overnight, please make sure to flush the system out with pure water before performing the check.
If the result looks good, then simply continue on with your measurements! Though, in the case that results are outside the expected range, proceed to clean (our guide on cleaning) and perform a second check. If after cleaning, the results are still outside the expected range, proceed to the calibration step outlined in 2. below.
2. Calibration
For most needs, calibration simply requires you to run the ‘Water Only’ calibration function using pure water (alcohol content of 0.00vol% at 20°C). If desired, the instrument is also capable of running a calibration using both dry air and pure water (the ‘Air & Water’ calibration setting). To perform air calibration you will need to prepare your own external air pump. ‘Water Only’ calibration is quick and saves on time and labor, whilst the “Air & Water” calibration function is available for those that need it to, for example, adhere to a certain Standard Operating Procedure (SOP).
Before performing calibration, be sure to rinse and clean the measuring cell thoroughly with pure water. Attempting calibration when the cell is unclean, foreign substances are present, or air bubbles are in the water standard, will throw the calibration off, leading to inaccuracies in subsequent measurements.
“Water Only” calibration procedure.
Our video on "Water Only" calibration.
1) Press the [FUNC.] key.
2) Navigate to the "Function 0 Calibration" option with the [△][▽]keys and press the [ENTER] key.
3) Navigate to the "Calibration Water Only" option with the [△][▽]keys and press the [ENTER] key.
4) Press the [PUMP] key and run at least 20mL of pure water through the system so that the cell is adequately pre-washed. This pre-wash process can be enhanced by introducing small amounts of air into the system, achieved by withdrawing and replacing the tube tip into the water 2-3 times in quick succession mid-pump.
5) After pre-wash, continue pumping pure water into the system until the cell is completely filled and that enough water has been pumped through the sample outlet (50~60cm worth of tube travel distance), pressing [PUMP] to stop the pump.
6) Check the cell for air bubbles, and if there are none, press the [ENTER] key to commence calibration.
7) A message will flash on the screen indicating that the machine is currently performing calibration.
8) If the calibration was successful, ‘OK’ will be displayed on the screen. If the calibration was not completed successfully, ‘NG’ will be displayed, requiring you to perform it once again.
A word on our density liquid standards
Lastly, we would like to introduce the range of density liquid standards that we sell and manufacture. Density liquid standards are used to calibrate oscillation-type density/specific gravity meters, ensuring their optimal operational quality. Our reference materials laboratory is accredited by International Accreditation Japan (IAJapan) as an Accredited Calibration Laboratory in accordance with ISO/IEC 17025 and successfully operates a quality management system in accordance with ISO 17034. IAJapan is an accreditation body of the Japan Calibration Service System (JCSS), whose accreditation process conforms to ISO/IEC 17011 and relevant international criteria. IAJapan is a signatory to the Mutual Recognition Arrangements (MRA) of both The Asia Pacific Accreditation Cooperation (APAC) and the International Laboratory Accreditation Cooperation (ILAC). Our reference materials laboratory is accredited under the JCSS which corresponds to the international MRA. "JCSS 0115" is our lab’s assigned accreditation number.
List of our density standard products
*Expanded uncertainty obtains from the t-distribution a coverage factor k which has a level of confidence of approximately 95% in effective degrees of freedom veff and is the value determined from combined standard uncertainty. (Coverage factor k=2; Effective degrees of freedom veff = 182.8)
We hope that you enjoyed the article! If you have any questions, or would like a quote for the ALM-155 Alcohol Meter, please feel free to contact us by clicking the yellow “contact” button at the top of the page! Thank you for reading.