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Modern, high-quality technologies ensure a continuous stress-free production process in plants. When detecting filling levels in silos and material processing processes. Sensors with high compatibility for different process vessels offer multiple support. It is always depending on the processing stage. The material to be controlled may be of a different nature or used for different demands on the measuring technology to be used. The UWT range offers capacitive measuring technology, oscillators and mechanical solutions for use in both solids and liquids. The solutions for the soldering system and non-contact radar technology were extended by an innovative TDR product line in continuous measurement. Depending on the process conditions and the medium to be measured. The appropriate sensor technology can be configured from a comprehensive stock. A cement manufacturer, producing in Poland has already implemented the guided radar in some warehouse processes.

Precise level measurement in the storage process

To ensure a continuous value-added chain, both the raw products and the final finished product must be stored properly and transparently. In a cement plant or in the production of clinker and concrete within cement plants, these are, in addition to the finished cement types, various raw products of building blocks and earths which undergo different processing stages on the way to the final product in the plant. A certain amount of water is optionally added to the respective mixtures. In particular phases of the production process, the solids in particular have different densities, different particle sizes with different dust development and a differing moisture content. The storage containers of a cement plant in Poland vary in their height very individually and reach sporadically up to 100 meters. The raw ballast is brought to the cement works via conveyor belts or with rope and railways. Here it is stored in a mixed bed silo and homogenized. After extraction, conveying, crushing and homogenization, the raw material is ground to raw meal, deacidified and then fired in the rotary kiln at about 1450°C / 2642°F to cement clinker with particle sizes of up to 50 millimeters, which is then cooled and ground. Per blast fall amounts of rock of up to 19,000 tons. The homogenized raw material in Poland is processed almost exclusively dry. For this purpose, the raw material is dried during comminution in a rolling or ball mill with hot gas, usually from the exhaust gas of the furnace system. Occasionally, correction components such as silica sand or iron ore are added to adjust the required chemical composition of the raw meal. Alternative raw materials can also be added to the raw mill in order to achieve optimum mixing with the other raw materials. Large roller mills mill up to 250 tph (tons of raw meal per hour).

Therefore, a safe and high-quality measuring technology was indispensable for the equipment of the cement manufacturer. It depends on functionality, ease of use and long life of the products, in accordance with the high requirements of building materials industry. Innovative technologies combined with extensive industry knowledge enabled UWT GmbH to provide a comprehensive range of tailor-made measurement technology. UWT solutions for level and level measurement have been used successfully in silo plants and process tanks of cement plants worldwide for many years. In practice, the simple electromechanical measuring method of the plumb bob has proven itself several times. The sensor is considered as classic among overfill detectors and is often used for extremely adherent materials as well as existing braces in process vessels. Sometimes the FMCW radar level transmitter is also used. In particular, where in non-contact applications a contactless measuring technique is desired. Hard measurement in solid and liquid materials is provided by TDR sensors. These guided radars are used for consistently accurate continuous level measurement under difficult varying process conditions with high pull-off forces, caking or condensate formation. A reliable overfill protection and empty message is guaranteed.

Simple, universal and reliable with guided radar sensors

Due to the versatility of its process conditions, the plant operator decided to install several guided radar sensors within the warehouse processes. This insensitive technology is regarded as a multi-talent in all matters and consistently delivers a reliable level signal. High-frequency microwave pulses are coupled to a cable or rod and guided along the probe. The emitted pulse is reflected by the product surface. The time difference between the transmitted and reflected pulse is converted into a level. Unlike the lot, the guided radar does not contain any moving parts inside the process vessel. In contrast to non-contact radar, microwaves are emitted at lower frequencies, so that even with high dust intensity, no spurious reflection is generated. As a result, the energy content of the microwave can be used exclusively for determining the specific filling level. It is therefore optimally suited for use in dusty environment storage processes such as those in the building materials processing industry. It is protected against thawing explosions and precisely measures + -2mm even under difficult process conditions in silos, tanks and pipes. Two series have been implemented, the NivoGuide® NG 3000, which is specifically tailored to the needs of solids, and the NivoGuide® NG 8000 for applications in liquids, pastes, foam, slurries, oils as well as for interface measurement. The device versions are each equipped with arms that can be individually adapted to the application with rod and cable extensions.



The NivoGuide® NG 3000 was initially used in raw material and clinker silos as well as in cement storage. In addition to the high safety standards that have to be met, a number of other factors played a decisive role in the efficient use of the appropriate measurement technology. Thus, during the storage and processing processes within the cement plant, often attachments to the boom, which can lead to faulty circuits. In such process vessels, the rope version of the guided NivoGuide® 3000 radar had to be chosen because it has a special PA coating to prevent both adhesion and a solution for abrasive media. The PA coating also improved the abrasion resistance of the ropes, as fine-grained bulk materials could not settle in the mesh of the rope. The rope strengths are to be applied depending on the silo height and mechanical load. This can play a role in bulk materials with corresponding particle sizes (with clinker up to 50 millimeters) and high pull-off forces, which justifies the consideration of the TDR`s probe bushing specially designed for the building materials processing sector. In fact, an optimized coupling to the bulk goods area was installed, which is characterized by an axial support of the probe inside the process connection and which differs constructively from conventional guided radar sensors. As a result, the tensile forces acting on the probe were optimally distributed, which allowed a load of up to 30kN (kilonewtons). Different rope diameters of 4 and 6 millimeters are optimally designed for the prevailing tensile forces. The rope therefore does not travel under high load and supports the endurance of the sensor. Generally, a thicker rope should be used for high silos. In terms of their construction, the ropes of the TDR solid, unlike the guided radar for liquids, are equipped with twisted thicker strands. In addition, the weave of the ropes is such that in liquids a flexible rope and for solids a rather rigid rope that hangs tightly in the silo is used.

With the rod version of the NivoGuide® series, with a 16 millimeters rod diameter, the resistance to bending during surface movement of the bulk material during filling or emptying was increased. The recording of the rod and rope boom also differed depending on the medium, this is conical in liquid devices to allow dripping.

When using in the narrow, high silo containers for cement storage could be used with the rope version of the NG3 with long measuring distances of up to 75 meters without loss of performance. The mounting position that is required can be a wall distance of only 30 centimeters. Typical filling properties such as moisture content, mixing ratio or particle size did not matter and made the planning easy. There were also accurate results when there are changes in the temperature conditions, pressure and DK values as there wasn’t the need to adjust the respective medium.

Intelligent TDR with helpful diagnostic options

The intelligent software of the guided radar sensor system enables high system availability. Echo curves are recorded and stored. The sensor can learn and will know which signals are changed and which are constantly in one place. Disturbing installations can be identified and service technicians` operations are avoided due to faulty level signals. The programming element is with an attachable display, an adjustment module as well as a cover with a vision retainer that makes the operation of the TDR NivoGuide® very user-friendly. Extensive diagnostic functions ensure fast and safe handling such as, current measured values and commissioning parameters are displayed. The parameterized data can be stored and transferred to other guided radars that result time saving in the installation process. The guide is in 5 easy steps that are intuitive to the application with optimal adjustment of the sensor. It will be very easy for the plant operator to quickly put the NivoGuide® sensors into operation.

Transparency and planning security through visualization

Users with a number of storage silos, tanks and pipes that are placed scattered can also consider it very necessarily for their systems to be equipped. This will be very useful for the continuous measurement of the fill level. This can be preferably done with an automated visualization and monitoring of the data. The detected measurement results of the sensors will be displayed quickly and easily with a software that an always be accessible from the screen. Effective silo logistics also increase transparency and planning security for the plant operator. The TDR series of the NivoGuide® has been equipped with the appropriate equipment, which includes an analogue 4-20mA signal as well as a Modbus RTU or Profibus DP interface for the evaluation systems.

The data visualization provides the plant operator with levels in the amount, percent, weight or volume for a transparent cement production. Trends are saved and emails via fill levels or silo messages can be activated. The individual level sensors can also be parameterized. Clean route planning and targeted stocking for cost optimization in the delivery of materials can be facilitated.