Application Case of Low-Temperature Conveying of Freeze-Dried Fruit Pieces by Stainless Steel Vertical Screw Conveyor

1. Application Background and Material Characteristics

In the production of freeze-dried fruit powder, the freeze-dried fruit flakes need to be vertically fed from the storage silo into an ultrafine pulverizer. This material has extremely low moisture content, a loose and brittle structure, is sensitive to metal contamination, and the fruit powder is prone to oxidation and discoloration. Traditional pneumatic or mechanical conveying methods result in high breakage rates and significant dust generation, making it difficult to meet quality requirements.

2. Equipment Selection and Key Designs

A stainless steel vertical screw conveyor is used. The entire machine is made of food-grade 304 or 316L stainless steel, with a mirror-polished inner wall to prevent material from adhering to the wall and metal foreign objects from mixing in. To accommodate brittle materials, the equipment is equipped with a low-speed, high-torque drive system and adopts a full-fill operation mode, allowing the material to rise steadily in a continuous flow, reducing the compression and collision between particles.

3. Operational Results and Quality Assurance

In actual application, the material breakage rate is reduced by more than 50% compared to traditional conveying methods, dust generation is significantly reduced, and the working environment is noticeably improved. The stainless steel construction eliminates the risk of contamination from metal friction, ensuring that the metal residue in the freeze-dried fruit powder meets industry limits. The sealed structure can also be equipped with a nitrogen inlet, continuously introducing nitrogen into the cylinder during transport to replace internal air, effectively inhibiting the degradation of easily oxidized components (such as vitamin C and anthocyanins), and maintaining the product's color and nutritional value.

4. Cleaning, Maintenance, and Production Integration The equipment features quick-opening inspection doors and clamp connections, supporting daily rapid disassembly and cleaning. The design eliminates dead corners, preventing the growth of microorganisms from fruit powder residue. The entire machine can seamlessly connect to upstream and downstream buffer silos and ultra-fine pulverizers, forming a fully enclosed, low-breakage, and oxidation-resistant high-quality freeze-dried fruit powder production line.