As an international active and renowned manufacturer, supplier and service provider for devices, systems and systems for the contactless detection of various process parameters (e.g. density and humidity) mainly of bulk materials (e.g. coal and potassium salt) we want to offer our customers the most effective solutions for their processes.
The possible technical solutions are ultimately defined by analyzing the customer processes and the operating conditions on site. You can find out how these can look in this section.
Despite the use of modern conveying and sorting methods, the production of coal involves a huge amount of unusable material that cannot be easily separated from the coal.
These non-combustible components are called ash content.
The ash content (measured in% by weight in the fuel) must be determined in order to minimize the cost of coal extraction, but also to keep the calorific value as high and uniform as possible.
Based on the coal content in the seam, the ash content in hard coal is e.g. mostly below 12% and together with the water content forms the ballast content.
Mining is a costly and resource intensive industry with significant environmental impacts, but as long as we have not said goodbye to fossil fuels, it remains an important economic and energy supplier.
Electromagnetic waves such as X-rays or gamma radiation, which will be absorbed through matter in different ways, are used as the measurement principle.
It depends on the energy which process predominates:
if the radiation has a high energy, it is absorbed according to the density, of course also according to the thickness of the material layer.
Low energies are also absorbed according to their atomic weight, i.e. the heavier the atom, the better it is absorbed.
Therefore, it is important first of all that a low level of radiation energy is available if the purpose of the measurement is an analysis. However, the density and the layer thickness are also always included in the measurement.
Since the change in density and / or height is not known, both must also be measured and this influence, which falsifies the measurement of the low energy, must be mathematically compensated for.
This measured value is generated with a radiator of higher energy, in which the absorption is not influenced by the atomic weight.
The two-component mixture can then be determined mathematically from the two signals.
Even in many industrial processes, the density - either it the specific density or the bulk density - is required to infer other process parameters, for example to determine the concentration of a two-substance mixture or the solids content when transported through pipelines.
The density can in this way be measured continuously in an ongoing process.
In order to measure radiation, it must be absorbed.
The denser the absorbent material, the stronger the absorption.
If a gas-filled counter tube or an ionization chamber is used as the detector, the absorber is a gas with a very low density, which means that most of the radiation passes through without interaction.
On the other hand, if a sodium iodide crystal with a higher density than gas is used, most of the radiation is absorbed.
The radiation in the crystal generates flashes of light, which are captured with a photomultiplier, converted into electrical impulses and then recorded by evaluation electronics and converted into a corresponding value.
For this purpose, this evaluation unit not only has to accomplish a high computing effort, but also take over the automatic correction of all changes due to temperature or possible aging of the electronic components, since the spectrum of the radiation must be analyzed and kept constant.
The radiation sources for the high and low energy are built into lead housings that only release the radiation in the direction of the detectors, whereby either the radiation source or the detector is installed below, the other part above the belt and thus the material to be measured.
Radiation source and detector together form a measuring section, whereby two measuring sections, which should have a distance of at least 2m from each other, are necessary in order to provide a usable, usable measurement result by the evaluation computer delaying the first signal and calculating it at the same time as the second.
In principle, it would be possible to build both radiation sources and both detectors in one housing each, but the separation of the two energies is more complex than two detectors and two lead shields, furthermore the mutual influences cannot be separated and experience has shown that the system is more difficult to control.
The detector and the radiation source must be mounted on a stable frame so that no changes in the distance distort the measurement.
Our staff would be happy to help you and take care of your inquiries and orders.
You can get help and advice on the selection of the measuring system that best suits your application
from our experts in process measurement technology.