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Hygienic big bag emptying made by Engelsmann

» Fig. 1: A strong team and a guarantee for quality: Markus Plitko (Construction, right) and Sascha Müller (Assembly, left).

Customers often come to us with exciting challenges. One recent example of this was a manufacturer from the pharmaceutical industry who was looking for a dust-free big bag emptying solution for their lactose production.

They needed one special feature in particular: They wanted one emptying station to transfer product to two different subsequent processes. They needed the lactose to be emptied from big bags into an available pneumatic conveyor system (incl. a mobile rotary valve) and then conveyed to silos for storage. But they also wanted to use the system for the dust-free filling of containers without having to worry about time-consuming conversions.

This is where the bulk solid experts from Engelsmann come in. A big bag emptying station tailored to the needs of the customer, and capable of mastering the challenges listed above, was designed and created. To ensure a high level of product quality and safety, a protective screening and metal separator were also to be integrated into the emptying process. The customer can use an operating platform to help them operate and maintain their system comfortably. The required throughput for emptying the lactose was 3 t/h.

So how did we do it?

» Fig. 2: Frame structure made from stainless steel. Rockers help to efficiently discharge the product.

The big bag emptying station was designed as a stable frame construction made from stainless steel. There is a lifting cross in the upper area that helps the operating personnel to bring the big bags into the correct position for emptying.

In order to remove the lactose from the big bag as completely and efficiently as possible, there are rockers installed on the sides of the emptying station. They also serve as additional guardrails for the big bags, which can weigh up to 1250 kg.

» Fig. 3: Thanks to its dead-space free design and smooth surfaces, the hopper can be easily cleaned without there being any residue left behind.

The big bag outlet is connected to a dust-tight big bag hygiene hopper. In order to establish a connection between the big bag outlet and the hopper, all you have to do is activate a hand lever, which can be operated without excessive force thanks to the pneumatic springs. The hopper opens, the big bag outlet is placed over the product carrying tube inside the hopper, the hopper is closed so that it is dust-tight again and the big bag is then opened.

This way, the product can be emptied in a controlled way. The on-site operating platform provides easy access to the emptying hopper and other system components. From here, the operating personal can also take samples from the emptying hopper if needed.

» Fig. 4: Magnetic separator and pneumatic filling head. Both filters on the filling head filter the dusty air during the filling.

A dust-tight round vibration screening machine is connected directly beneath the emptying hopper. In this particular case, a JEL Fix was integrated directly into the emptying frame as it has a low installation height. The screening machine guarantees a homogeneous particle size and reliably removes impurities and contaminants from the screened product. The operator can inspect the screen mesh and product flow through a viewing window.

A dust extraction filter in hygienic design with a ventilator is connected with the aspiration nozzle on the screening cover. The dedusting is done when the product falls from the emptying hopper and onto the screen mesh.

After the protective screening with the JEL Fix, the material falls from the screening machine through a metal separator. Here, any remaining metal particles are removed from the product flow with a magnet. This acts as a second safety step after the protective screening.

Beneath the metal separator there is a pneumatically-operated filling head with a support plate. In normal operation, the product passes from the filling head into the on-site rotary valve. The filling head and rotary valve are connected by means of a downpipe, the lower end of which is fixed to the outlet of the rotary valve. The downpipe is attached to one of the lateral cross struts on the emptying frame and can be moved directly under the filling head. Once the filling head is pneumatically lowered onto the upper end of the downpipe, a dust-tight connection is created thanks to the seal on the bottom side of the support plate. The lactose will then fall through the pipe and into the rotary valve, from where it is metered and discharged into a silo via a pneumatic conveying line.

» Fig. 5: Setting during normal operation (left image). The product is screened, checked for remaining metal particles and then transferred to the pneumatic conveying line via a downpipe. Right image: Setting for container filling. The swivel arm is folded away to the side to make room for the container that is to be filled.

  1. Stable frame construction made in stainless steel
  2. Rockers
  3. Hygienic Big Bag emptying hopper
  4. Protective vibration screen JEL Fix, incl. dedusting filter in hygienic design
  5. Metal separator
  6. Pneumatically-operated filling head with a support plate, sealing and displacement filters
  7. Swivel arm with downpipe connection to rotary valve for silo filling

Alternative option: Container filling

Equipping the system for container filling can be done in just a few steps. First, the downpipe and rotary valve must be disconnected and the filling head moved back up pneumatically. The downpipe attached to the swivel arm must be folded back into its starting position. A lock function stops it from swiveling out again. The rotary valve can then be removed from the station and the free space can be used for the container that is to be filled. As the container must be placed directly below the filling head, the operator is guided by distance sensors when moving the container into the frame. Once the container is in the correct position, the filling head with sealing plate will be lowered over the container and the filling can start. Any dusty air coming from the container is removed by the displacement filter on the filling head.

» Fig. 6: First image: View of below through the filling head (with support plate and seal) and view of the metal separator. Sensors help the operator to position the container precisely beneath the filling head (second image).

Hygienic design and explosion protection

To empty a big bag hygienically, the entire emptying station is designed in such a way as to prevent contamination by product residues or any other impurities. This is why our big bag emptying frame has a fully hygienic design. Large radii, closed round tubes and beveled corners in the frame design help to prevent any unwanted dirt deposits. Both the hygiene hopper and protective screen have no dead space and have particularly smooth surfaces (surface roughness ≤ 0.8 µm). Stainless steel 1.4401 has been used for all parts that come into contact with the product. All seals, adhesives and other similar materials used all comply with EU Regulation 1935/2004, Directive 2007/72/EC and all applicable FDA guidelines.

As the production environment of the customer is an ATEX protection zone, the entire system was designed in accordance with Directive 2014/35/EU of the European Parliament and Council.


Multiple functions in a small space: The total installation height of the big bag emptying station is approx. 6 m, with a floor space of almost 3 m². A special solution, tailored to the needs of our customer which includes the emptying of big bags, protective screening, metal separation and flexible connection options that allow the customer to connect the station to their downstream processes. The comparably low extra costs proof, that special tailored solutions are not always expensive. On the contrary, our customer got a solution that optimally uses the available space in their production plant and that flexibly reacts to different production situations. Less individuality often means greater compromise at the expense of the cost-effectiveness and efficiency of production.

Do you have any questions about hygienic big bag emptying?
We look forward to your call!

Ansprechpartner Moritz Meier

Waldemar Gischa
Big bag systems

Tel.: +49(0)621 59002-17