Tubular Drag Chain Conveyor Working Principle

What Moves the Material

A tubular drag chain conveyor uses a circulating chain with conveying discs inside enclosed tubes. The drive pulls the chain through the circuit; the discs move the material toward the discharge. A tensioning mechanism maintains the chain arrangement, and the return tube completes the circuit.

The conveying tube contains the material path. Feed and discharge points, inspection ports and the return run remain part of the complete system rather than separate conveyors.

Pipe chain conveyor showing chain-mounted conveying discs — Chain-mounted discs inside the conveying circuit.

Horizontal Transfer: Material Moves Between Discs

In a horizontal section, the discs push the material forward as a bulk mass. The spacing between feed and receiving equipment determines the useful conveying run, but the return tube and bends also occupy space and contribute to the circuit.

Several inlet or discharge points can be included. Their operating sequence must keep material moving toward the intended receiver without overfilling the tube.

Vertical Transfer: Discs Support the Lifted Material

In a rising section, the discs support and lift the solids. The LIYOU brochure notes that reduced filling helps limit fallback. Vertical duty therefore depends on material density and loading as well as height; the horizontal capacity cannot simply be assigned to every vertical route.

Vertical pipe chain conveyor with a feed hopper and rising tube — Feed hopper and rising tube in a vertical pipe chain conveyor arrangement.

Bends Connect Points Around Existing Equipment

Large-radius elbows change direction along a fixed tube route. The circuit can combine horizontal runs, lifts and bends to connect equipment that is not aligned. Bend geometry affects disc passage, material impact and contact with the tube wall. Inspection points need to remain accessible after installation.

Curved pipe chain conveyor with inlet hopper and drive assembly — Curved tube route with an inlet hopper and drive assembly.

Material Groups and Conveying Conditions

Dry-solid transfer covers more than flour or plastic pellets. The material groups below need different control of pickup, deposits and contact surfaces; the same tube diameter does not establish the same mass throughput for every product.

Dry-solid conveying examples and practical conditions
Material group	Examples	What matters in the circuit
Chemical powders and pigments	Sodium bicarbonate, soda ash, titanium dioxide, iron oxide, sodium phosphate	Powder pickup, dust containment, product-contact compatibility and colour-change residues
Mineral fillers and building powders	Calcium carbonate, talc, kaolin, bentonite, cement	Bulk density, cohesive grades, moisture-related lumps, tube and disc wear
Plastics and resins	PET and other pellets; PVC and other resin powders	Pellet fines, powder cohesion, static behaviour and grade-change cleaning
Grain and food ingredients	Wheat, rice, corn, flour, starch, sugar, salt	Grain or crystal damage, cleanout, moisture and contact-grade requirements
Feed and fertilizers	Animal feed pellets, dry feed ingredients, urea and fertilizer granules	Pellet breakage, caking and formulation carryover
Adsorbents	Activated carbon powder and granules	Powder containment, granule friability, residues and dust-specific protection

Powder Pickup, Deposits and Contact Materials

A cohesive powder can bridge above the inlet while the conveyor itself remains clear. Pigment deposits at bends and discharge faces can contaminate the next batch. Mineral powder grades differ in density and wear behaviour; granules can generate fines through repeated contact. These are different causes and should not all be treated by increasing motor power.

Carbon steel, 304 stainless steel and 316L stainless steel are catalogue construction options. The chain, discs and seals also need compatibility with the product and cleaning exposure. Food, chemical and dust-hazard duties cannot be assigned the same contact or protection arrangement simply because the tube is enclosed.

Use the GL-Series Data for the Complete Route

The catalogue covers GL89 through GL325. Capacity is given in m³/h, alongside tube outside diameter, maximum horizontal distance, maximum lift and motor-power ranges.

Read the GL-series specifications and capacity explanation, or compare the Pipe Chain Conveyor, horizontal, vertical and curved arrangements.

Download the LIYOU GL-series brochure (PDF)