Patent ID: 8596300

Claim:
A tool for generating pulses in a flow of liquid passing through the tool, wherein: the tool includes a body, and the body includes an inlet port and an outlet port, for conveying the liquid into and out of the tool; the tool includes a rotor, which is mounted in the body for rotation about an axis; the rotor has a curved-face, which is circular with respect to the axis of rotation; the tool includes an insert, and includes an insert-guide; the insert-guide is structured to guide the insert for movement relative to the body towards and away from the rotor, in a guided-direction; the guided-direction is either perpendicular to the axis of rotation or has a major perpendicular component; the insert has a curved-face, which is so profiled as to complement the curved-face of the rotor; the insert includes a through-hole in its curved-face, termed the insert-aperture, which is open to a through-flow of liquid; the rotor includes a through-hole in its curved-face, termed the rotor-aperture, which is open to the through-flow of liquid; one of the apertures is fluidly connected to the inlet port and the other to the outlet port; the tool is so structured that, in operation, with the rotor rotating, and with liquid being passed through the tool under pressure, from the inlet port to the outlet port: (a) the insert is biased into contact with the rotor; (b) the curved-face of the insert makes rubbing contact with the complementary curved-face of the rotor, curved-face to curved-face; (c) the rotor-aperture alternates cyclically, in time with the rotation of the rotor, between being in liquid-flow-conducting alignment with the insert-aperture, and being out of alignment; (d) a liquid-flow-conducting pulse-aperture opens between the rotor-aperture and the insert-aperture when the rotor-aperture and the insert-aperture are in alignment; (e) the pulse-aperture alternately opens and closes, on a repeating cycle, in time with revolutions of the rotor, whereby the liquid that emerges from the outlet-port emerges in cyclic pulses.