The Paderborn company Gebrüder Lödige Maschinenbau GmbH specializes in the production and development of application-specific technology, and is a recognized expert for basic process engineering operations such as the mixing, drying and granulation of bulk materials. For a large order from the food industry, Lödige used extremely reliable industrial gear units from NORD DRIVESYSTEMS.
Each of the customized mixers, dryers or reactors which Lödige supplies to the food and pharmaceutical industries, as well as to the chemical and construction industries throughout the world, contains 79 years of process engineering experience. With the development of its ploughshare mixer in 1949, Lödige caused a revolution in mixing technology. Ploughshare mixers achieve high quality mixing with short mixing times and are exceedingly gentle on the product. They operate according to the hurling and whirling method, which was developed by Lödige.
The material to be mixed is always in full contact with the blades, so that there are no low movement zones. With this technology, various process stages can be combined, e.g. mixing, drying and granulation of a product.
Ploughshare mixers – for versatile use
FKM series ploughshare mixers work with production batches and are used for various mixing tasks in almost all industries. They consist of a horizontal, cylindrical drum in which the central shaft equipped with ploughshare blades creates a mechanically generated fluid bed in the product. Due to the intensive mixing and the frequent contact of particles with the optionally heated wall of the apparatus, a high level of heat transfer can be achieved without local overheating. During drying, the intensity of particle movement increases as the moisture and viscosity of the mixing material reduces.
Mixing what is difficult to mix
For a large order for a food manufacturer in West Africa, Lödige built eight large and ten smaller mixers for use in a newly constructed production facility for instant soups and bouillon mixtures for the West African market. NORD DRIVESYSTEMS from Bargteheide supplied the necessary drives for all 18 FKM series ploughshare batch mixers. The fact that the most versatile machine from Lödige can process products which range from very dry powders to sticky and partly fluid substances with almost any consistency, is especially important for bouillon production: For various recipes, powders with a high salt and sugar content, colorants, aromatic oils, spices, melted fats such as palm oil and poultry fat as well as other liquids have to be as homogeneous as possible. Due to the different solubilities of the ingredients in fat and water, this is a very demanding task. In addition, a defined level of swelling of the dry starches must be achieved in the wet phases. The finished bouillon is then pressed into stock cubes, which are wrapped in foil and packaged for delivery to retailers. Instant soups or granulated bouillon are filled into jars, stick packs, stand-up bags or tubular bags. For this, the pourability and measurabilty of the product is important. The ploughshare batch mixers must be able to quickly achieve the required properties for each recipe and batch in a precise and reproducible manner.
The right power on the drive shaft
The heart of the mixer is the drive shaft, on which the precisely calculated and aligned mixer blades are mounted, and which gently transfers the necessary mechanical energy into the material which is to be mixed at the right speed. The industrial gear units from NORD DRIVESYSTEMS transfer motor powers of up to 110 kW to the mixer drive shafts. Christian Schilken has worked for Gebrüder Lödige for three and a half years and is responsible for the sale of machinery for the food industry, as well as for the cosmetics and pharmaceutical industries. “We don’t deal with such a large international order every day. Therefore it is important that everything goes smoothly with our suppliers and we can rely on uncompromising quality and global service. With NORD DRIVESYSTEMS the entire package was right and we are very satisfied with the implementation of the project” says Schilken about the cooperation in the project.
Since the end of 2015, the gear unit experts from NORD DRIVESYSTEMS were in contact with the project managers at Lödige in order to precisely design all of the gear units and geared motors to meet the requirements of the user. The right series production products and the necessary equipment features had to be determined in detail in order to ensure a precise design. Thanks to the rapid delivery capability of the company, acceptance by Lödige was carried out in April 2016 at the NORD headquarters in Bargteheide, with subsequent delivery to Paderborn. Christian Schilken recalls: “The cooperation was smooth and efficient. We only needed to mount the components on the 18 mixers and after short tests were then able to ship the machines to West Africa for commissioning.”
High performance series production gear units
The eight large mixers have a gross volume of 3,000 liters each and can produce one ton of product per batch. For this, NORD DRIVESYSTEMS supplied eight SK 7207V helical gear units and couplings with 140 mm x 250 mm solid shafts, which with a speed ratio of 14.20:1 and up to 1,480 rpm, provide an output torque of 10,078 Nm. The 486 kilogram two-stage gear units are within the mid-range of the eleven sizes of NORD industrial gear units. NORD produces this type of gear unit as UNICASE gear units for torques of up to 250,000 Nm. Machining of all bearing points and sealing surfaces in a single step not only ensures high precision of the axes and quiet, low vibration running, but also a longer service life and less maintenance. For example, with a one-piece industrial gear unit, there is no separating joint in the housing and therefore no sealing surfaces which are subjected to torques. Last-not-least, with regard to the planned continuous production of the new plant, reliable, low maintenance operation is essential.
Large torques, even for small mixers NORD equipped four other batch mixers, each with a production volume of 1,200 litres, with complete two-stage helical geared motors, which with motor powers of 30 kW and a gear ratio of 12.51:1 deliver torques of up to 2,415 to the drive shafts.
Five smaller batch mixers with 15 kW parallel shaft geared motors with hollow shafts and drive torques of 1,061 Nm produce dry pre-mixtures along the process chain, which are then further processed in the large batch mixers. For the development of products, the customer ordered a further 130 litre laboratory mixer with a 7.5 kW helical geared motor. NORD supplied the geared motors ready for installation and equipped for operation with food grade oil class CLP PG H1 220.
According to the customer’s requirements, Lödige integrated the connections and attachment components for all of the production mixers with uniform dimensions to ensure interchangeability. However, the Lödige experts demonstrated their real expertise in mixer construction with the 3,000 litre mixers, which had to be produced with two different geometries due to different room heights at the user’s premises: Both short and squat, as well as long and thin versions of the same mixer were constructed. In spite of this, the two versions have exactly the same mixing characteristics and the same NORD industrial gear units on the drive shaft. Christian Schilken sums up: “80 years of know-how in mixer construction makes many things possible. However, our process technology would not work without reliable drive components such as NORD industrial gear units. Because of this, dependable and professional partners are essential in mechanical engineering.”