The modular hoppers can be used for buffering a product and steady feeding of sequential machines in a processing line. The bunkers are suitable for potatoes, onions, carrots, sprouts, beets and other vegetable crops, among others. In addition, the bunkers are suitable for loosened product. The modular construction of the bunkers consists of a basic frame topped by side walls 0.5 metres high. The height can be extended as required. The unloading belt at the bottom of the hopper is equipped with frequency-controlled transmissions for variable speed adjustment.