AN ELECTRONICALLY controlled "intelligent" mechanical seal could increase the payload capacity of liquid-fuelled space vehicles, claims the Georgia Institute of Technology, which has developed a device with support from NASA's Lewis Research Center.

The seal would allow higher payloads to be carried, as it is lighter than other devices used for keeping hot exhaust gases separate from liquid oxygen.

"With the intelligent seal, you can save weight and at the same time maintain safety and high reliability," says Dr Richard Salant, professor of mechanical engineering at the institute.

At the heart of the intelligent seal is a piezo-electric crystal, which deforms in proportion to the electrical voltage applied to it. Attached to one face of the seal, the crystal would adjust the spacing between critical moving parts in a rocket engine's turbo-pump. A closed-loop control system would constantly monitor the seal and determine the voltage, required to maintain adequate clearances.

Source: Flight International