Abstract: A portable excavator having a tube to point a supersonic gas stream at a buried object. The excavator includes a movable member disposed within the conduit to pulse gas passing through the conduit and a supersonic gas nozzle at the exit of the conduit. Compressed gas delivered to the conduit exits the nozzle in a pulsed manner at two to three Hz. The movable member includes a piston which blocks gas from flowing through the conduit by the biasing force of a spring. When the force to the pressure differential across the piston exceeds the biasing force, the piston moves and allows gas to flow through the conduit until the force from the pressure differential across the piston is less than the biasing force.

Abstract: An electromagnetic flow control valve for an electrically conductive liquid having a plurality of coils and yokes surrounding a non-metallic, such as alumina, tube through which an electrically conducting liquid, such as liquid metal, flows. Direct current applied to the coils causes retarding forces to be imposed on the flowing liquid. The electromagnetic flow control valve can be used in conjunction with a continuous caster where the electromagnetic flow control valve is in fluid communication with a tundish.

Abstract: A portable excavator having a tube to point a supersonic gas stream at a buried object. The excavator includes a movable member disposed within the conduit to pulse gas passing through the conduit and a supersonic gas nozzle at the exit of the conduit. Compressed gas delivered to the conduit exits the nozzle in a pulsed manner at two to three Hz. The movable member includes a piston which blocks gas from flowing through the conduit by the biasing force of a spring. When the force from the pressure differential across the piston exceeds the biasing force, the piston moves and allows gas to flow through the conduit until the force from the pressure differential across the piston is less than the biasing force.

Abstract: An integrated safe excavation apparatus utilizing supersonic air jets coupled with high flow, pneumatic vacuum transport and a unique separation system to excavate earth and other like material for the purpose of repairing, replacing or installing buried utility lines, remediating contaminated soils, uncovering buried objects containing discarded hazardous waste, safely exposing unexploded ordnance and other like operations.