Unloading bag-in-the-box containers with free or not so free-flowing or lumpy products
Advantages of using the Ehcolo CTT unloader “Classical” way of unloading b-i-b CTN’s: Bag-in-the-box unloading using a fish- tail to connect outlet spout to the rotary valve (truck mounted or not). Compressor can be truck mounted or not. One or two container doors are open.
2 . Problems encountered during unloading b-i-b CTN’s by the “classical way”
1. Lumps in product blocking “small” outlet 2. Compacted product not moving through “small” outlet 3. Safety: liner bulging out 4. Badly installed liner 5. Risk of major product spillage when liner breaks
3 1. Lumps in product blocking outlet :
Lumps (even friable lumps) in the product block the outlet spout of the liner or the grid on the rotary valve (discharge spout ≈ Ø 425 mm).
4 2. Compacted product not moving through “small” outlet
Compacted product can form bridges Even with fluidizing pipes, it is over the outlet or needs to be tilted up difficult to get compacted product to > 35°to get moving. flowing through the outlet spout.
5 3. Safety: liner bulging out
Even with mail-box discharge CTN: liner bulging out due to very fluid product
Standard CTN: retention bar bended due to product pressure -> bar could be dislodged and liner sliding out. Safety issue !!!
6 4. Badly installed liner
Sometimes, it can happen that the liner is badly installed (un-trained installation people), which causes problems to install the unloading device.
7 Improved Ehcolo CTT unloader
Ehcolo CTT first unloader was available on the market to unload fish-meal The unloader was not designed to unload powders Together with Solvay Ehcolo improved and adapted the unloader for powders The improved Ehcolo CTT unloader is patented by Ehcolo A/S and Solvay SA
8 Opening of the taped discharge gate in the bulkhead sleeve (protective cover in woven PP). The PE liner itself remains closed! Liner and CTN ready to receive unloading unit Unloading unit attached
9 Moving the unloader by a forklift to the open CTN, hanging it into the upper twist locks and securing it by the lower twist locks
10 large hatches to access the liner (with safety switches)
Ready to connect degassing line from RV to the liner and to cut open the liner …
11 Once the unloader is firmly attached to the CTN, the liner can be cut open. A flap of the PEHD liner has been cut open (as the dashed line) . The flap is folded over the connection between unloading unit and container to avoid product spillage View of cut away flap positioned over junction between unloading unit and container frame Remark that product is very compacted and not free flowing!
12 3. 1. 2.
1. Tilting of CTN to start product flowing out of CTN into unloading unit (CTN tilted 25 – 35°) 2-3. Inside views: product flowing into unloading unit; big lumps in unloaded product, broken up by screw and breaker bars 4. CTN and unloader empty 5. Removing unloading unit from empty CTN (note some product spilled on the floor)
4. 5.
13 View of the left hand part of the build-in screw conveyor with notched flight. The screw conveys the product from both View of the central outlet with the breaker sides to the central outlet, which is bars on the central part of the screw and protected by a cover. the grid mounted in the outlet
14 Realized improvements ….
View of CTN’s General view Right side after fitting on container uneven frame 1. The sealing installed on the lower half of the unloading unit’s frame was improved (thicker and larger).
15 Realized improvements ….
Before modification
2. To have an easy access to the grid (cleaning), the access door to the central part of the screw was enlarged and equipped with quick locking system and security switch. The product detection sensor was mounted above this enlarged door. In case of blockage of the grid by parts of hard lumps, the cleaning will be much easier.
16 Realized improvements ….
3. To have an idea of the counter pressure of the pneumatic conveying line to the silo, a manometer (0 – 1.6 bar) was installed on the pipe just before the rotary valve.
17 Realized improvements ….
New inclined SS pipes instead of horizontal flexible hose and manual slide valve removed. Before
4. The manual slide valve was removed (to unload compacted bicarbonate, we don’t really need the slide valve but we can imagine however that it might be necessary to unload free flowing products). 5. The collector from both leakage air outlets was modified (inclined stainless steel pipe instead of horizontal flexible hose) in order to avoid blockages by dust settling down.
18 Realized improvements ….
New grid Old grid
Breaker bars with paddles/knives Breaker bars with paddles/knives and grid mounted below 6. The original grid is replaced by a new grid one with more open surface (mesh size 50x160 mm) and mounted closer/flush to the breaker bars; the breaker bars are equipped with paddles/knives to break up lumps and “clean” the grid.
19 Realized improvements ….
7. The motor and reductor of the screw conveyor (actually 1.1 kW) was increased (2.2 kW – 1400 rpm – reduction 1/36.9)
20 Realized improvements ….
Pipe inserted in liner, fixed to the Z-shaped rigid pipe (PVC) liner, attached to the retaining bar and connected to the collector by a hose
8. To improve the connection of the rotary valve’s leakage air collector to the liner, a Z-shaped rigid pipe (PVC pipe with beveled end) was used. This pipe is inserted into the liner for approximately 300 mm, fixed to the liner with tape and attached to the bulkhead’s superior retaining bar.
21 Realized improvements ….
Handgrip
Gangway with plastic grating
Step
9. To increase safety during the cutting operation of the liner, a small gangway (plastic grating), a step and a handgrip were fixed on the unloading unit.
22 Advantages of this unloading unit: - Safety: complete back of open CTN is covered - The complete unit, with rotary valve, is attached to the CTN in a few minutes (time saving) - The liner can be cut open over the entire width, enabling an extremely large outlet for not free-flowing products - A build-in screw conveys the product to the central outlet and aerates compacted product - Build-in breaker bars with paddles/knives break up possible lumps - A build-in grid retains possible remaining lumps - Leakage air from the rotary valve is send back into liner. If strictly no dust emission is allowed, the degassing air can be connected to a dust filter on site - Simple liners can be used - Even badly installed liners can be unloaded - Only simple tilting frame needed: rotary valve is build-in, compressor can be on truck or on site Inconvenient: - Client (or transport company) must dispose of such a unit;
23 Thank you for watching, if you need further information, contact Ehcolo A/S.