Baffle plate

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A baffle plate is a - mostly perforated - partition wall in liquid containers that are moved with vehicles.

functionality

A historic tanker truck

When accelerating (including braking) a container that is partially or not completely filled with liquid, for example in a moving tanker , the liquid shifts due to its inertia .

This means that the liquid sloshes forwards when braking and backwards when accelerating . When cornering, the centrifugal force causes the liquid to be shifted to the outside of the curve. The driving safety of a vehicle can be significantly impaired by the movement of the load in the container.

To reduce this effect, one or more baffles, i.e. partitions, are built into the tank. They are perforated and do not lead all the way to the top or bottom of the tank. As a result, when the force is no longer acting on it, the liquid can again spread evenly throughout the tank with a little delay.

In vehicles

There are also baffles in the fuel tank of motor vehicles, here also to reduce noise, and in the oil reservoir of the engine . When cornering quickly, this prevents the oil from migrating to the side, the oil intake port from sucking in air and thus interrupting the engine lubrication.

Ships

Cross section through a tanker

Free liquid surfaces on ships are very dangerous as they can capsize in rough seas. That is why tanks must not extend across the entire width of the ship; they are to be subdivided by lengthways bulkheads , because in the half-filled state the contents would increase the movement when rolling . If water has penetrated the rooms, there is the same problem. RoRo ships in particular , in which the vehicle decks close to the sea surface can have large spaces that span almost the entire width of the ship, are problematic. Here it is required to insert longitudinal walls in sections; however, this reduces the transport capacity.

Slosh cage

Sloshing cage (No. 12 in the picture) in a tank (LiquidOXygen) of the Saturn I rocket

So-called slosh cages take on the same task in rocket tanks. This prevents the movement of the liquid fuel from causing the rocket to tumble or from the acceleration forces causing the fuel to swing “up” and “down” and, for example, not reliably supply the engines ( pogo effect ).

literature

  • Hans-Hermann Braess, Ulrich Seiffert: Vieweg manual automotive technology. 2nd edition, Friedrich Vieweg, Braunschweig / Wiesbaden, 2001, ISBN 3-528-13114-4

source

  • Sloshing cage in the collection of the Deutsches Museum