Intake Pit and Bin Gates in Grain Handling

Two duties, two quite different problems. At the intake pit the gate receives everything the truck delivered: grain, soil, stones, string, bolts and whatever was in the trailer before. A blade clearance sized for wheat jams on the first piece of scrap, and the jam breaks the actuator.

Under a bin the gate is a safety device. Entry into a grain bin is one of the industry's recurring causes of death, and every entry procedure depends on being able to show that the outlet is closed and cannot open. A gate whose only indication is the command it was given does not provide that.

Flowing grain is what kills. A person on the surface of a bin when material starts to move has seconds, and the material does not have to be moving much. That is why the isolation point matters more than any other characteristic of the gate.

And the dust is explosible. A gate that leaks dust into the building contributes to the layer that turns a primary event into a secondary one.

Bin gates with a lockable closed position and an indication that is independent of the control command, named in the written entry procedure.

Intake gates built and sized for foreign material, with clearances that pass what the truck brings and a drive that stalls safely rather than deforming the blade.

Dust tight closed positions throughout, so the gates do not feed the layer that the explosion protection concept is trying to remove.

In a fuel and ash bin the deciding document is the fuel envelope, because a gate specified for coal is defeated by the fibre in the biomass that replaced it.

Bin gates are specified from the entry procedure backwards. The procedure names an isolation point; the gate has to be able to be that point. In practice this means a mechanical locking arrangement that can take a padlock, a position indication derived from the blade rather than from the actuator, and a design where a partly open blade is visibly partly open.

Intake gates are specified for abuse. Generous clearance, a robust blade and frame, stall detection on the drive, and an accessible clearing point so a jam can be cleared without entering anything. Jamming is more likely than leakage here, and the design should fail towards a stalled drive rather than a bent blade.

Dust tightness is then specified for both duties, because the gates are numerous and every leak adds to the housekeeping burden the explosion protection concept depends on.

Finally the fleet question applies as it does to all grain plant equipment: few types, interchangeable parts, and devices placed where the site team can reach them.

• Bin gates specified from the entry procedure, with a lockable closed position.
• Position indication derived from the blade rather than from the actuator command.
• Intake gates built with generous clearance for stones, bolts and string.
• Stall detection so a jam stops the drive instead of deforming the blade.
• Accessible clearing points so a jam never requires entry.
• Dust tight closed positions, since leakage feeds the layer the protection concept must reduce.

• Foreign material expected at intake, which sets clearances and blade robustness.
• Entry procedure and the isolation points it names, which is the governing requirement for bin gates.
• Dust explosion characteristics of the grain dust and the housekeeping burden of leakage.
• Peak intake rate at harvest, which is far above the annual average.
• Access for clearing without entering a pit or a bin.
• Commonality across the plant, since there are many gates and one spares list.