The HydroTracer determines the water content of the sample with a chemical method. The introduced sample is heated in the reactor, water is converted into hydrogen, the hydrogen content is detected by a sensor. This patented measuring method specifically measures the water content, other volatile ingredients are not detected.
Yes, for all engineering plastics in the field of injection molding. No false measurements are known to us. An exception is PVC – here the thermal stability has to be considered.
The thermogravimetric moisture analyzer consists of a scale with an overhead heating lamp. The sample is heated on the scale, the weight loss is postulated as water content. This simple method is practical for the determination of high water contents, e.g. in foodstuffs, when the proportion of water is very high compared to other contained volatiles.
Disadvantages: No water is determined, but a weight loss. The cause of the weight loss can not be determined. This can be water or caused by other volatile substances such as plasticizers, paraffins, fire inhibitors, etc.
A frequent sales argument for thermogravimetry is the hypothesis that at a low heating temperature (for example, 110 ° C.) the proportion of the other volatiles can be neglected. On the other hand, at these temperatures in the presence of atmospheric moisture, the water only partially escapes from a hygroscopic test material until a state of equilibrium with the water content of the air is reached.
A further disadvantage is the heating lamp: Contrary to the statements of the manufacturers, it is not possible to heat a plastic granulate evenly by means of heat radiation. The surface will absorb more heat than the core. This accelerates the thermal degradation of the plastic (and therefore the weight loss). This is clearly visible in the case of translucent material on the basis of the discolouration.
The measuring range is between 0 mg and 25 mg of water.
The measurement accuracy is 0.1 mg in a range from 0 mg to 5 mg of water,
0.2 mg in a range of 5.1 and 15 mg of water and 0.3 mg in a range of 15.1 and 25 mg of water.
Conversion of the absolute average measurement error of the HydroTracer
To determine the relative water content of the sample material, the water mass of the sample is divided by the weight of the sample.
A water content of 1 mg is determined during a measurement, the sample mass was 1 g. The average error (standard deviation) according to the calibration certificate is 0.1 mg. The relative water content is thus: 1 mg / 1000 mg = 0.001 = 0.1% = 1000 ppm. Neglecting the weighing error, the average error of the relative water content is 0.1% x (± 0.1 mg / 1 mg) = ± 0.01% and ± 100 ppm, respectively
A water content of 1 mg is determined during a measurement and the sample mass is 20 g. The average error (standard deviation) according to the calibration certificate is 0.1 mg. The relative water content is thus: 1 mg / 20000 mg = 0.00005 = 0.005% = 50 ppm. Neglecting the weighing error, the average error of the relative water content is 0.005% x (± 0.1 mg / 1 mg) = ± 0.0005% and ± 5 ppm, respectively
These examples illustrate the great importance of the sample quantity to the accuracy of the measurement result.
A calibration is included in the initial delivery. The measurement accuracy can be checked by the customer, but we recommend the maintenance and calibration by aboni.
Explanation of the calibration certificate for the moisture analyzer HydroTracer Type HT3
The calibration is based on a method described in ISO 15512:2019 “PLASTICS – DETERMINATION OF WATER CONTENT”.
A defined amount of an analytical salt is heated to 150 ° C in the closed reactor, thereby ensuring complete evaporation of the entrapped water. The salt used is sodium molybdate dihydrate, the crystal water content of it is 14.89 mass%.
The salt is weighed with an analytical balance, the resolution of the scale is 0.01 mg, the accuracy +/- 0.03 mg, so the accuracy of the water weighed is 0.03 mg x 0.1489 = 0.005 mg.
The traceability of this method is based on a tested scale with which the calibration salt is weighed.
The average results must be within a tolerance range.
The allowed values are:
0.1 mg in a range of from 0 mg to 5 mg of water,
0.2 mg in a range of 5.1 and 15 mg of water and
0.3 mg in a range of 15.1 and 25 mg of water.
The absolute limit of 0.1 mg for a sample weight of 10 g is equal to the relative limit of 0.001% = 10 ppm.
The absolute limit of 0.1 mg for a sample weight of 20 g is equal to the relative limit of 0.0005% = 5 ppm.
The recommended time until the next calibration is
1 year with continuous use,
2 years with regular use,
2-3 years for occasional use.
The current control program of the HydroTracer runs under Windows XP (check in individual cases), Windows 7, Windows 8, Windows 8.1, Windows 10. The RAM size should be 1 GB or more.
A USB-port to connect the HydroTracer is necessary.