Big Bag Filling systems / Super Sack Filling systems
Also known as...
FIBC filling
Flexible container filling
Do you have a question, a remark ? Please contact the author at admin@powderprocess.net| Section summary |
|---|
| 1. What is a Big Bag filling station |
| 2. Design of Big
Bag filling stations |
| 3. Performances of super sack loading stations |
| 4. Safety of Super Sack fillers |
| 5. Common problems with Big Bag
tipping stations |
| 6. Super Sack filling systems manufacturers |
1. What is a Big Bag filling station
Big Bag filling stations allow to fill bulk bags of powder or granules in many industries and for many applications :
- Construction industry : cements, mortars
- Food industry : flours, maltodextrins, sugar
- Chemicals industry
- Plastics : polymer pellets
Big Bags, also known as FIBC or super sacks, are a very popular packaging to handle bulk solids such as powder, granulates, in all bulk solids industries. Big bags, or Super Sacks in the US, can be used within the process of a factory, to constitute buffers and transport the material from one point to another, or can be used to export the product and sell it to a customer. In any case, the factory must be able to fill the FIBC in an efficient way, which means safely, quickly, and while containing dust emissions.
2. Design of Big Bag filling stations
The following items are to be taken into account when designing a Super Sack filling station.
Big Bag (FIBC) dimensions
This looks obvious, but many time at the 1st use of the filling station, the Big Bag is not fitting...
The min and max dimensions of the Big Bag must be well defined when ordering the filling station. One particular dimension to check is the diameter and the length of inlet the spout to be connected to the filling station head.
Access
It is a key point for having a Big Bag filling station that will yield a good performance : Big Bags are tall and reaching the inlet spout, to connect it to the head of the station is not possible if the operator cannot stand on a platform. It is thus necessary to have a platform all around the station, except for the side where the FIBC will be removed, so that the operator can reach the Big Bag inlet spout and the hanging loops.
Handling help
Even with a platform, as described above, the access can be tricky. This will be sufficient for stations of low capacities, handling maybe 2-3 Super Sack / h but will prove to be a bottleneck as soon as the station will be used more intensely, as the operator will struggle to connect the empty Big bag which will slow the whole process, and create safety concerns if the operators takes risks to speed up. For such high capacity stations, options such as moving filling station head, that allows to bring down the top of the station while the operator connect the Big Bags, are necessary.
When the Big Bag is full, the weight is pulling on the Big Bag hanging loops which makes the disconnection difficult. For this reason, some manufacturer have developed some rotating hooks that allow to automatically release the Big Bag once full.
Dust free filling
One of the key design success criteria of a filling system is to be able to fill fast while containing any leakage of dust. For this, the filling station must be equipped with :
- A dust tight clamping system for the inlet spout
- A filtration system
The inlet spout must be clamped tightly to the filling tube. In low capacity systems, this can be done through a simple mechanical clamp that is pressing the bag spout to the discharging tube, but in high capacity systems a design using an inflatable seal is more and more common. Inflatable seals allow an easy and quick fitting of the spout while ensuring perfect tightness.
The filling of powder to the bag is most often fast, several 1000 l/h, and therefore is displacing a lot of air carrying dust. In order to ensure a high capacity of the filling line, the air displaced must be vented at the inlet of the Big Bag filling station, otherwise it will prevent a good filling as air will go up through the filling tube. At minimum, a filtering sock (cloth) must be installed but it is acceptable only for small capacity systems as it tends to clog and leak dust with time. More efficient are systems with pulse jet systems, coupled with an extraction fan. The auto cleaning will extend the life cycle of the filter and those systems are generally well tight.
Big Bag inflation before loading
It is difficult to shape properly the Big Bag before filling, especially if there is a liner (2nd bag in the Big Bag to avoid humidity pick up for example). Such an operation takes time and for high capacity lines this is impacting too much the cycle time of the filling operation. It is then possible to install a fan that will blow the empty Big Bag prior to filling and shape it so that the filling is as efficient as possible.
Load cells
Some processes are designed to fill the Big bag at a given weight, it is thus necessary to know the weight of the Big Bag, which is done by installing load cells on which the Big Bag and its supporting pallet will rely or put the entire station on load cells (some flexible for the inlet pipe is then required).3. Performances of super sack loading stations
The FIBC filling station must be designed to load a certain number of Bulk Bags per hour. The cycle time achievable is made of the following components :
- Connecting the Big Bag to the filling station (inlet spout clamping, hooking...)
- Inflation of the Big Bag if required
- Filling the Big Bag
- Disconnecting the filled Big Bag
- Removing the Big Bag from the loading station
Connecting the Big Bag to the tipping station
As explained above, the time to connect the empty Big Bag to the tipping station will greatly depend on the design of the station. For low capacity stations, this can take more than 5-6 minutes while high capacity stations having movable head, automatic clamping system and Big Bag inflation can do it in 2-3 minutes.
Filling the Big Bag
In many case, the discharge to the Big Bag is done from a hopper located above the station, it will thus be quite fast and will depend upon the size of the pipe going to the FIBC and on the efficiency of the air venting.
Disconnecting the Big Bag
Removing the hanging loops of a filled super sack from the supporting hooks can be very tedious as the bag is pulling on the loops. The disconnecting time will thus depend if the station is equipped with a system allowing to automatically release the hooks of the Big Bag. Without the system, the operation could last 3-5 minutes, especially if the operator needs to readjust the height of the Big Bag with a forklift, then return to the platform to remove the bag. With the auto release system, removing the Big Bag will take 1-2 minutes.
Removing the Big Bag from the tipping station
This operation is usually fast, especially if the plant is equipped with electrical forklift.
4. Safety of Super Sack fillers
Big Bag filling station have some inherent risks linked to the manipulation of large and heavy powder containers. It is necessary to manage those risks.
Risk : fall of Big Bag
An incorrectly hooked Big Bag can fall during the filling process. As the Big Bag is normally supported by a pallet or lifted not high above, this risk is generally manageable. However it remains a good practice to have fences on the platform built around the station, and to prevent the presence of pedestrian in front of the station from where forklifts will remove filled Big bags.
Risk : ATEX
As every equipment processing powder, the ATEX risk needs to be considered when designing and sourcing a Big Bag station. The 1st condition is to prevent dust leaks, which means that the Big Bag station head clamping the spout must be well designed and tight. Finally, the ATEX rating of equipment must be performed and equipment sourced accordingly, with certification.
5. Common problems with big bag filling stations
Big Bag filling stations are usually reliable equipment, however a certain number of issues may require some corrections :
Table 1 : common problems with big bag filling station
| Issue | Recommendation |
|---|---|
| Dust emission during tipping | Make sure that the clamping head is properly tight, that the filters are well installed |
| Filling of the Big Bag too slow | Check that the filter is not clogged |
6. Super Sack filling systems manufacturers
Meeting all the design requirements mentioned above requires expertise. It is important you partner with a reputable and experienced company in designing the filling station that you need for your company. It is important that, before contacting any company, you build a URS (User Requirement Specifications) that define precisely what you think you need for your application, the explanations given in this page can help you to do so. Possible references of loading stations suppliers :
- www.mecabag.com
- www.palamaticprocess.fr
(Note that PowderProcess.net has no link with those companies)