Moisture affects the processability, usability and quality of many plastics. Therefore, information and control of moisture content is very important. But if you want to measure moisture in plastics, it will take some time. The specifications for moisture in plastics are often very low (<250ppm). The most commonly used analyzer for determining moisture (or dry matter content) when using an oven is the halogen dry matter meter. This works according to the 'loss on drying' principleprinciple. However, the halogen balance is not sufficiently sensitive to measure the low moisture levels in plastics. The Karl Fischer method is sensitive enough, but there are many conditions attached to it. Both methods are very time consuming.
A method that is used in-line in many processes is near-infrared spectrometry. Although this method is fast and can be applied in-line, it is not sensitive enough to the low moisture specifications of plastics.
Fast and accurate moisture measurement in plastics
With TEWS' patented microwave technology you can measure moisture in plastics up to 250 ppm. The unique sensor measures the moisture both on the surface and in the core of the product. Because changes in color, density and mass do not affect the measurement, the result is reliable and accurate.
TEWS Elektronik offers lightweight portable instruments, laboratory analyzers and a in-line (bypass) solution that are able to measure very low moisture contents in plastics.
Moisture measurement in plastics with microwave technology
Below we take a closer look at the results, benefits and implementation of TEWS moisture and density meters. We have opted for various production lines for the manufacture of PVC (products). If you have any questions about the use with other applications, please contact Product Manager Kees van der Sar on tel. no.: 0162 460404 or via e-mail.
The inspection of PP granules (density) and PVC powder (moisture) in the laboratory
Compared to conventional halogen dryers, TEWS Elektronik analyzers offer significant time savings when measuring moisture and density. Preparing and measuring samples with a halogen dryer takes approximately 6 to 7 minutes. With the TEWS analyzer this time is reduced to approximately 1 minute.
In addition, the reaction time of the dryer speeds up, preventing you from doing so scrap or rework and the operator can guarantee product quality more quickly and accurately, ensuring faster time to market.
In-line measurement of PVC during the drying process
After the drying process, the plastic PVC has a moisture range between 0.1% and 0.3 %. In the drying process, moisture and density measurement can be installed with a bypass solution. The bypass sensor enables simultaneous moisture and density measurement every 30 seconds. This measurement has a standard deviation of 0.017% and high reproducibility (correlation: 0.9987).
TEWS's in-line moisture and density measurements help you on your way to automating your internal processes (Industry 4.0) and fully control your plastic drying process online, which saves energy and costs.
Conclusion measuring moisture in plastics
Whether we are talking about powders, granules, flakes or plates, the high-quality moisture and density meters from TEWS Elektronik help companies easily achieve their goals. Chemical companies are thus able to quickly and very accurately determine the moisture content and density of their products. Without any sample preparation, the entire production process is optimized, leading to significant cost savings and excellent quality control.
Contact about a moisture measurement in plastic
Would you like more information about moisture measurement in plastics specifically aimed at your application or are you interested in a test? Please contact Product Manager Kees van der Sar via tel. no.: 0162 460404 or e-mail. He will be happy to help you.
Nederlands