Abstract: Seal assemblies are provided. In one embodiment, an example shaft seal assembly comprises an immiscible fluid and a reservoir structure. The immiscible fluid is immiscible with respect to a contained internal fluid in an enclosure with a penetrating shaft. The reservoir structure is disposed in close proximity to the shaft, and the reservoir structure contains the immiscible fluid. The immiscible fluid of the seal assembly provides a fluid barrier to the internal fluid to limit loss of the internal fluid over time.

Abstract: An excavation head, mounted on one end of a telescoping hollow boom, has nozzles for directing jets of high speed air at an excavation face to loosen soil. A vacuum transport pipe extends from the excavation head through the hollow of the boom to a spherical joint. The spherical joint movably joins the other end of the boom to a primary separator. The primary separator is a chamber for disentraining loosened soil from air flowing through the primary separator. A primary air lock is fixed to the lower portion of the primary separator for expelling soil from the primary separator. A secondary separator is joined to the primary separator by way of a separator connector pipe. A secondary air lock is fixed to the lower portion of the secondary separator for expelling soil from the secondary separator. A positive displacement vacuum pump has its vacuum side pneumatically connected to the secondary separator.