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Techmatic Baghouse and ESP Dust Conveyors

Baghouse ConveyorDo you need a hassle free, flexible solution to move your baghouse dust to a central storage silo – we have the solution!

We can collect material from multiple outlets on your baghouse, electrostatic precipitator (ESP) or baghouse cyclones and pneumatically convey it to a central point. Cleanly and efficiently with a flexible pipeline routing and space saving installation.

Twelve years ago the founding members of the company put their heads together to find a solution to the problem of airlock abrasion, pipe blockages and pipeline overloading on existing pneumatic conveyors.

The requirements: An airlock feed system that ensures a positive seal at all times. A feed system that can accommodate large numbers of infeed points without losing valuable conveying air through those infeed points. The system must be maintainable without downtime. The system must accommodate and be able to recover from material backlogs in the baghouse hoppers. This last point is crucial as the system needs to be designed around the 0.2% of the time that the baghouse is not running under normal conditions i.e. the hoppers are full of material due to possible conveyor downtime or larger volumes of material dropping off the bags at any given time.

The result was the development of the double pneumatic flap valve with rotary actuators as the main component in the airlock mechanism.

The flap valve functions like the double security doors in banks. The top flap opens to allow material to flow through into an intermediate chamber and then closes. Only then does the bottom flap open to release the material into the conveying pipeline. The flat rubber moulded lining of the flap ensures that a positive seal is achieved against the feed and outlet chute. Air leakage is kept to a minimum and only consists of the pressurised air volume between the two flaps. No continuous air leakage – no sandblasting type abrasion wear.

A further advantage is that the flaps are replaceable with the unit installed. The flap replacement kits can be kept on the shelf with no machining required before installation.

Rotary actuators are used on the flap valves for superior life cycle expectancy compared to the traditional linear cylinders.

The initial capital outlay of the double pneumatic flap valve system is higher than with a system using rotary valves alone. The potential operational savings are in terms of maintenance, reduced downtime and hassle-free operation.

Flap valves cannot accommodate a head of material above the inlets. With a potential head of material above the feed arrangement (which may be present as result of a backlog due to plant stoppage and surges or material that is dislodged from the bags) a rotary vane feeder is used to meter material into the flap valve. Rotary vane feeder tip wear is not a concern as the sealing against the conveying air pressure is accomplished by the flap valve. The only function that the rotary vane feeder serves in this system is as a metering device.

Techmatic has also developed a special pipeline bend to counter the potential bend wear problem that is traditionally associated with pneumatic conveyors. In-situ tests on conveying highly abrasive Sinter dust have shown the life expectancy of these bends to be more than 24 months.

A final advantage is that the system can handle coarse material without a problem. To prove the point the test rig was used recently to pneumatically convey 20mm road gravel using the double pneumatic flap valve – a point well worth taking into consideration when looking at moving the coarse material from the baghouse cyclones to a central silo. The system is ideally suited for conveying diamond tailings with a pneumatic conveyor.

Currently the Techmatic baghouse dust conveyor is installed on plants such as Arcelor Mittal, Highveld Steel, Samancor, Richards Bay Minerals. Tubatse Ferrochrome, Glencore Xstrata and Assmang Chrome.

Speak to us about your requirements and we can advise on the best and most cost effective solution.

Schematic of a baghouse conveying system