Patent ID: 9239044
Filing Date: 2016-01-19
CPC Classification: F04B

Claim Text:
1. A lance pump for pumping a viscous liquid from a reservoir, said pump comprising: a pump body adapted for positioning above said reservoir; an elongate core extending downward from an upper end fixedly connected to the body, past an upper portion and a lower portion, to a lower end when the body is positioned above said reservoir; an elongate tube surrounding the core and extending vertically downward from the body into the liquid when the body is in position above the reservoir, the tube having a longitudinal axis extending between an upper end mounted on the body for vertical reciprocating motion and a lower end opposite the upper end extending past the lower end of the core, the tube having an upper closure and a lower closure slidably receiving the core and providing lateral support as the tube reciprocates; a motor comprising a stepper motor or a servo motor mounted on the body having a selectively rotatable output shaft extending horizontally above the liquid in the reservoir when the body is in position; a transmission operatively connecting the motor output shaft and the elongate tube for reciprocating the tube between the raised position and the lowered position as the motor output shaft rotates to drive the tube through alternating upward and downward pumping strokes; an inlet check valve mounted inside the tube below the lower end of the core and defining with the lower end of the core an expansible and contractible lower end chamber, the inlet check valve being oriented to open during each downward pumping stroke of the tube permitting viscous liquid to enter said lower end chamber; an annular pump chamber defined in part by the tube and the core above the lower end chamber; a feed passage in the tube connecting the lower end chamber to the annular pump chamber having a feed passage check valve oriented to open during each upward pumping stroke of the tube with the inlet check valve closed to deliver viscous liquid from the lower end chamber to the annular pump chamber; a pressure monitor in fluid communication with liquid in the pump downstream from the feed passage check valve for measuring pressure of said liquid; an outlet passage connected to the annular pump chamber permitting viscous liquid to flow from the annular pump chamber to an outlet on each upward pumping stroke and each downward pumping stroke; and a control operatively connected between the pressure monitor and the motor for controlling operation of the motor in response to a signal from the pressure monitor, and wherein the control controls the motor to effect a selected number of upward pumping strokes and downward pumping strokes to deliver a predetermined quantity of viscous liquid through the outlet, thereby providing a predetermined quantity of viscous liquid at a predetermined pressure.