Big bag emptying when the product flows heavily and clumps

Methacrylamide in the chemical industry

Methacrylamide is used as a binder for medicines. It is also supplied to the food industry as a thickener and stabiliser. It is found in cosmetic products, as well as in detergents, paints or adhesives.

What is good for its functionality as a binding and thickening substance is unfavourable when it is emptied. The substance, which is crystalline in its original form, tends to form lumps. Therefore, problems regularly occurred during emptying and feeding into the production process. 

Previously, our customer, a company from the chemical industry, purchased methacrylamide in 25kg bags. The sacks were emptied with a sack chute, a lot of manual effort and the use of lifting and conveying tools – including lumps. Depending on how much care was taken in the production of the methacrylamide, the delivered material was interspersed with various large lumps. When emptied with the bag chute, they were not completely dissolved.

Overall, the process was not only cumbersome, but also affected the quality of further production processes: After emptying, the methacrylamide was placed in an on-site stirred tank to mix in a solvent that would prevent it from clumping again. However, the contained lumps made the dosing of the agent imprecise, which resulted in quality deficiencies in downstream process stages.

In order to make the emptying and feeding process more efficient, the chemical producer switched to big bags and an individually designed big bag emptying station from Engelsmann. This now ensures smooth emptying of the big bags and lump-free transfer of the methacrylamide to the following stirred tank.

All-round carefree package: Beam pressure and flexing devices break up caking and lumps in the big bag – for a smooth material flow through the discharge hopper into the discharge device. This means that the product can be discharged without lumps.

First conception, then construction

Tests in the technical centre bring clarity and process reliability. Then a space-saving big bag emptying station is manufactured.

Methacrylamide does not clump and flow out of the big bags without aids. This had to be taken into account in the planning and construction of the big bag emptying station – as well as the low room height at the installation site.

Together with the customer, a test setup was set up in the Engelsmann technical centre and the big bag emptying was simulated on the basis of the designed system solution. The tests provided important findings for the design of the system and gave the customer the certainty right at the beginning of the project that the system would function perfectly in real operation later on.

With the new big bag emptying station from Engelsmann, the methacrylamide is now safely emptied from big bags in the production process and transferred to a continuous process via a discharge device.

Efficient emptying of methacrylamide from big bags in seven steps

Step 1: A crane track is used for loading big bags. It is integrated into the emptying station and equipped with a chain hoist and loading gear. The loading gear is extended and lowered to pick up the big bags.

Step 2: The four loops of the big bag to be emptied are hung in the loading gear, the big bag is lifted with the positioning gear and brought into the station. It is not yet placed completely on top.

Step 3: First, a pneumatic fulling device is used. The beams of the crusher attack the product clumps in the big bag from two sides over a large area and break them up before emptying.

Step 4: Still hovering above the actual emptying position, the big bag is lowered a little further and the beam crusher is used again. Once all the coarse clumps have been broken up, the big bag is set down.

Step 5: The discharge spout of the big bag is manually connected to the discharge hopper of the station. An integrated pressure plate holds the outlet securely during the emptying process. The big bag can be opened safely and emptying started.

Step 6: As soon as the emptying of the big bag starts, the fulling device is switched on again. The last coarse lumps are broken up further and the methacrylamide is emptied smoothly from the big bag in this way.

Step 7: A spring tensioning device on the loading gear keeps the side walls of the big bag tautly stretched upwards during the ongoing emptying process, so that no residues of methacrylamide get stuck in the folds of the big bag and everything is discharged completely.

Brought back into crystalline form – ATEX included

The methacrylamide is emptied from the big bag directly into a discharge device designed for the continuous process

The JEL AV discharge device removes the heavy-flowing product almost completely and dissolves the last lumps. Brought back to its original particle size, the methacrylamide can now be transferred to the following process in homogeneous and lump-free quality.

In the discharge device, the methacrylamide slides downwards due to the negative conical design of the container bottom and is continuously transported to the discharge opening with the help of the discharge arms. The pre-comminuted lumps are broken up further in the process, so that the methacrylamide is once again of a homogeneous particle size at the end. It can be picked up by the on-site screw conveyor and fed to the next process section in a dosed manner. A weighing unit is integrated in the big bag emptying station for this purpose. In the downstream agitated container, this now enables the precise admixture of the active ingredients, which prevent the material from clumping again.

All components are Atex certified, as the big bag emptying takes place in a potentially explosive production area. The big bag station was implemented as a turnkey solution and manufactured by Engelmann with CE marking.

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