Hopper gates

Hopper gates: Hopper gates are the sliding doors at the bottom of each hopper on a grain trailer. Opened over a pit at an elevator, they let grain, feed or fertilizer flow out by gravity. Most hopper bottoms have two gates, opened by a crank or by air or electric openers.

How they work

A hopper bottom trailer has two funnel-shaped compartments under the load. Each ends in a gate that slides open across the outlet. The driver positions the trailer over the receiving pit, opens the gate a little to start the flow, then wider to empty the hopper, and closes it fully before pulling away. Manual gates use a crank; many trailers now use air or electric openers controlled from the side of the trailer or the cab.

Types and care

• Crank gates: simple and reliable, slower to open and close.
• Air or electric openers: faster and easier at busy elevators, with more parts to maintain.
• Seals: worn seals leak grain on the road and draw attention at scales.

In practice EXAMPLE

At a harvest-time elevator, a driver pulls over the pit, opens the front hopper's gate partway and watches the grain flow, then opens it fully. When the front hopper empties, they close it, pull forward and empty the rear. A gate left partly open after unloading spills product down the highway, so checking both gates is the last step before leaving. Hopper bottoms often run near the weight limit, so check axle groups with the bridge formula calculator, and read grain trucks for the trade.

Hopper bottoms beyond grain

Hopper bottom trailers also haul feed, fertilizer, soybean meal and other dry products, and some shippers require a clean-out between products. Fertilizer is corrosive to steel and aluminum, so carriers wash trailers after those loads. In harvest, hopper bottoms run long days between fields, bins and elevators, and waiting in line at the elevator is part of the job. Plan for it when pricing loads per bushel or per ton.

Before leaving the elevator, walk the trailer: both gates closed and latched, no grain on the gate assemblies or tires, and the tarp rolled and secured for the run home.