To ensure that the quality of the final product precisely meets the specified requirements, the correct concentration in the evaporator is an essential pre-condition. In an application, a drift in the measured value was detected with the previously used measuring method, which ultimately affected the quality of the end product. A test with the IRM-11 inline refractometer proved to be successful, the measuring accuracy is consistently high throughout the process and the composition of the milk powder can be precisely adjusted to the specified quality.
In many dairies, high-quality whey powder is obtained from various milk products in a spray drying plant. In this process, the quality of the end product can be tailored to the customer’s requirements by concentrating the preliminary product precisely to a specific dry matter content. In a recurring process lasting up to 24 hours, the preliminary product is evaporated upstream of the spray tower and cooled down again until the desired value is achieved. This is the moment when the spray drying is started. This is decisive for the economic success of the process: if the value deviates from the specification upwards, the cooler can clog and fail, leading to a reduced value. If the dry matter is too low, the end product becomes too dusty and is partially lost in the subsequent processing or it becomes completely worthless.
In this application, the dry matter concentration was previously determined using a density sensor. However, adrift in the measured value was detected, so that the quality no longer met the specifications precisely enough and the composition had to be checked several times. These laboratory analyses caused additional time expenditure which was clearly reflected in the economic results.
The new IRM-11 refractometer offers a reliable and constantly precise solution. With this inline sensor, the dry mass concentration can be measured directly inline using the Brix value. Due to the very compact size and the installation on a Varivent or Tri-Clamp process connection, directly and without bypass, the analysis sensor can be integrated into an existing process.
In practice, the IRM-11 can be “taught” to the process very pragmatically and easily. In a test run, a simple comparison between the values of the laboratory analysis and the refractometer measurement can be made. Thus the values to be specified are determined in °Brix and taken over as default for the production process. Depending on the required specification and composition of the final product, this default value can be set between 0 and 85° Brix for the IRM-11. The measuring interval can be adjusted individually from 2 seconds on, so that continuous and reliable process monitoring and thus the reporting of reaching the target value can be ensured in real-time.
Due to the optical measuring method of refractometry, a layer of lactose crystals can lead to measurement inaccuracies. The IRM-11 actively reports this by dropping the result to 0° Brix. In the evaporation process, however, in practice, hot water rinsing is usually carried out at certain intervals to prevent the cooler from clogging due to solid particles. In the described customer application, an optimal result was achieved by slightly shortening the intervals and the duration of the hot water rinsing cycle simultaneously.
Anderson-Negele offers an on-site test of the IRM-11 refractometer. The sensor itself can be used to test the measurement sensitivity of different products without installation in the process or even better can be tested in the application itself over a period of several days. If a Varivent or Tri-Clamp connection already exists, this is possible without additional effort, in other cases, an individual solution is offered. Interested parties can send a request to Anderson-Negele.