Yutung Industrial manufactures custom hollow spiral screws for vacuum screw dryers and continuous drying equipment.
Working Principle
The hollow spiral screw is the core heat transfer component of a hollow screw vacuum dryer.
Heat transfer media such as steam, thermal oil, or hot water flows inside the hollow shaft and spiral blades.
As the screw rotates, materials are continuously pushed forward while being heated indirectly, achieving efficient and uniform drying.
Structure
The hollow spiral flight is fabricated by welding two formed spiral sections together, creating an enclosed internal passage for steam, thermal oil, hot water, or cooling media.
The spiral flight is then assembled and welded to the hollow shaft according to the approved drawing and required heat-transfer design.

Application
It is used to dry or cool food, tea, or other materials.
When hot oil, steam, or hot water flows inside the hollow screw, wet materials are conveyed, heated indirectly, and gradually dried.
When cooling media are used, the hollow spiral screw can also cool hot materials before packing or further processing.
Hollow spiral screws are widely used in continuous drying equipment for industries such as:
- Chemical processing
- Sludge drying systems
- Food and pharmaceutical materials
- Environmental engineering equipment
- Industrial waste treatment
Machine
Our hollow spiral screw assemblies are used in vacuum screw dryers, hollow screw coolers, and continuous thermal processing equipment.
Customize
The screw flight size and material are fully customized. Outer diameter can range from 250 mm to 800 mm, and the maximum length can reach 6 meters.
We manufacture the screw flight/spiral flight together with the inner axis.
Production may involve screw flight forming, hollow shaft fabrication, welding, CNC machining, dimensional inspection, balancing, surface finishing, and assembly according to the customer’s approved drawings.
For custom screw shafts, spiral flights, machined shafts, welded assemblies, and other metal components requiring forming, fabrication, CNC machining, dimensional control, and inspection, explore our custom precision metal parts manufacturing capabilities.
Food-Grade Screw Applications
For food-processing applications, stainless steel such as 304 or 316 may be selected according to the handled material, corrosion conditions, cleaning method, surface-finish requirement, and applicable customer specifications.
Product-contact surfaces should be smooth and properly finished to reduce material retention and support effective cleaning.
Typical applications include food weighing and packaging equipment, food-processing machinery, and pasta or powder handling systems.

Screw Flight Project
We also manufacture customized screw flights for conveyor systems and drying equipment.
Yutung also has another business for conveyor screw flighting.





