Product Solutions

Project snapshot

• Location: Dalian, China
• Application: malt conveying from vessel unloading to storage at a grain terminal
• Capacity: 1,000 tonnes per hour
• Equipment: Recens air-supported (air cushion) belt conveyors with self-circulation air supply

What the terminal needed

A vessel unloading line is judged by one number above all others: how fast the berth is cleared. While a ship is alongside, every hour of conveying time costs berth occupancy, and the discharge rate has to hold steady through a shift rather than peak and fade. Malt adds a second constraint. It is a fragile, high-value brewing raw material, and it is dusty in a way that is immediately visible on a quayside. Broken kernels reduce malting value; escaped dust is both product loss and a complaint from whoever operates the terminal next door.

The conveying system therefore had to do three things at once: sustain 1,000 tonnes per hour from the unloading point through to storage, keep the material enclosed the whole way, and handle the grain gently enough that it arrived at the silo in the condition it left the hold.

Why an air-supported belt conveyor was chosen

An air-supported belt conveyor replaces the idler rolls of a conventional belt with a thin film of air. Air is fed into a chamber beneath the carrying belt, the belt floats on that film, and friction drops to a small fraction of what a troughed idler set produces. Two practical consequences follow, and both mattered on this project.

First, the belt is supported continuously along its whole length instead of at intervals, so the material rides without the small vertical agitation that idler spacing introduces. For malt, that gentler ride is the difference between whole kernels and cracked ones. Second, with no idler rolls to maintain along the run, there are far fewer bearings to fail in a line that may be hundreds of metres long and difficult to access once the structure is closed.

The Recens enclosed air-supported belt conveyor supplied for this line uses a self-circulation air supply, so the air that supports the belt is recirculated within the system rather than continuously blown into the surroundings. In an enclosed conveying line this is what keeps the dust balance controllable: the air path is closed, and the fines stay available for capture and return instead of being pushed out at every joint.

Enclosure and dust control along the route

Enclosure is not an accessory on a terminal of this type; it is the reason the installation can run at all next to other users of the quay. The air-supported conveyor runs inside sealed housing sections with welded, rustproofed joints and inspection access that can be opened without dismantling the run. A scraper on the return side keeps the inside of the housing clean, which carries on protecting belt tracking long after commissioning.

Transfer points are where the dust escapes on most terminals, so the same logic is applied at each one. A dust suppression hopper at the intake and discharge positions keeps the cloud from forming in the first place, rather than trying to collect it once it has spread. Where the route has to lift material rather than carry it horizontally, a bucket elevator takes the stream vertically inside a sealed casing; and where a single run has to feed more than one store, a plough tripper discharges at intermediate points without a second conveyor.

What this means for a comparable project

The Dalian line is a useful reference for any terminal or grain depot with the same three pressures: a berth or a receiving window that has to be cleared quickly, a fragile or dusty product, and a site where an open conveyor is no longer acceptable. The decisions that made the difference were not exotic. They were the choice of an air-supported belt for gentle, low-friction conveying, a self-circulating air supply to keep the dust balance closed, and an enclosure treated as part of the machine rather than a cover added afterwards.

If you are planning a vessel unloading or transfer line and want to know whether an air-supported configuration suits your material and route, send us the product, the required tonnage and the route length, and our engineers will look at it with you.

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