Abstract: For pulsed injection of liquids into the ground, the tool has a rotating cylinder, having through-slots. The tool has an insert, which is pressed against the rotating cylinder. As the cylinder rotates, the slots in the rotor cover/uncover the slots in the insert, creating the required pulses. By suitably shaping the slots, the pulses can have a fast rise-time from closed to open. The insert is shaped to minimize flow interference.

Abstract: A method is taught for applying vacuum pulses to enhance multiphase vacuum extraction of vapours and liquids from contaminated subsurface wells. The method involves first initiating continuous multiphase vacuum extraction from the subsurface well. Then one or more short vacuum pulses are imparted to the subsurface environment, to momentarily interrupt flow of vapours and liquids in the subsurface well. Time is allowed for a vacuum to build up in the extraction apparatus; and then the vacuum build up is rapidly released to momentarily increase velocity of vapours and liquids being extracted from the subsurface well. A device is further taught for imparting vacuum pulses to enhance multiphase extraction from contaminated subsurface wells, comprising a vacuum pulse tool having an inlet in fluid communication with the subsurface well and an outlet and one or more multiphase extraction vacuum pumps, connected to the outlet of the vacuum pulse tool.

Abstract: For pulsed injection of liquids into the ground, the tool has a rotating cylinder, having through-slots. The tool has an insert, which is pressed against the rotating cylinder. As the cylinder rotates, the slots in the rotor cover/uncover the slots in the insert, creating the required pulses. By suitably shaping the slots, the pulses can have a fast rise-time from closed to open. The insert is shaped to minimize flow interference.