M-DF1 Double Gate Bagging Machine

Why do two hoppers nearly double output?

In a single-hopper machine, every bag goes through three steps in turn: the hopper fills and is weighed, the product is discharged into the bag, and the hopper closes and starts filling again. Weighing stops during discharge. On the M-DF1 two hoppers work side by side. While the first discharges into a bag, the second weighs the product for the next bag; when the turn changes, so do their roles. Discharge time is thus hidden inside weighing time, and the filling spout hardly ever waits.

The second benefit concerns accuracy. On a fast single-hopper machine, the way to raise output is to shorten the fine filling phase, which increases deviation. With two hoppers, each one has more time for its own cycle. Because the pace can rise without cutting the fine fill short, the tolerance stays in the same ±50–150 g range as the single-gate M-SF1, even at 750 bags per hour.

Which plants suit the M-DF1, and where is it too much?

The hourly target decides. For a business staying below 440 bags per hour, the M-DF1 is larger than needed; the single-gate M-SF1 bags the same product with less space and a lighter structure. The M-DF1 makes sense at the point where the daily target can no longer be met with one hopper.

• Crop intake stores: at harvest, grain arriving by truck must be bagged and readied for dispatch within days; high output shortens that window.
• Dispatch departments of flour and semolina mills: lines running in shifts and filling 25 and 50 kg bags continuously.
• Export and ship loading: contract shipments where a set number of bags must be ready by a set date.

If your product is pellets, coal or pumice rather than grain, the belt-fed M-DB1 in the same output class is preferred; a gate is hard on coarse and fragile grains.

Balancing the line at high speed

Machine speed only helps as long as the rest of the line keeps up. For example, 720 bags an hour means one bag every 5 seconds (3,600 / 720 = 5). At that pace, putting the bag on the spout, closing the bag holder and dropping the full bag onto the conveyor must all fit into 5 seconds. The sewing machine and conveyor must also run at the same speed; otherwise bags pile up at the spout and the machine runs below its own capacity.

That is why our M-DF1 quotations cover not only the machine but also the bag placing point and the sewing and stacking arrangement. In practice, at this speed, placing bags and guiding full bags should be given to different people, and empty bags should be kept ready right next to the operator.

Installation and infrastructure

The M-DF1 weighs about 2,300 kg and carries a 3000-litre hopper on top. For example, if wheat is taken at roughly 0.75–0.8 kg per litre, a full hopper holds more than 2 tonnes of product. The steel structure or concrete floor the machine stands on must be planned to carry this total load safely. As the hopper volume is variable, a different size can be discussed to match the flow rate of your silo outlet.

Power supply is 400 VAC, 50–60 Hz three-phase. Two gates and the bag holder are moved by compressed air, so 8–10 bar is required; the technical table assumes a 300-litre compressor. Because the number of pneumatic movements rises at high speed, the cross-section of the air line and the compressor’s suitability for continuous duty deserve extra attention.

Keeping both hoppers equal in maintenance

On a two-hopper machine it is important that the two weighing paths do not give different results. If product builds up inside one hopper or a gate edge wears, bags start coming out alternately light and heavy. An easy way to spot this is to weigh several consecutive bags on a separate scale and compare odd- and even-numbered bags. If the gap grows, the hopper concerned is cleaned and recalibrated from the touchscreen panel. Making this check part of a weekly routine stops an unnoticed drift from spreading across hundreds of bags, especially during the harvest rush.