Stationary Outlet Stem Pump

A fluid pump comprising:

• a piston chamber-forming member defining a chamber about a chamber axis, the chamber having a radially inwardly directed chamber wall, an inner inlet end and an outer open outlet end,
• the inlet end of the chamber providing for communication with a source of fluid,
• the piston chamber-forming member including a center post member extending along the axis coaxially of the chamber outwardly from an axially inner end of the post member to a distal axially outer end of the post member whereby an annular compartment is defined within the chamber between the chamber wall and the post member,
• the post member having an outer wall coaxial about the axis with a radially outwardly directed post side surface,
• a center passage provided coaxially within the outer wall of the post member, the center passage open at a discharge outlet at the distal outer end of the post member, the center passage extending axially inwardly from the discharge outlet to a closed axially inner end,
• a transfer port radially through the outer wall of the post member providing communication between the center passage and the annular compartment through the outer wall,
• a one-way valve across the inlet end of the chamber permitting fluid flow outwardly but preventing fluid flow inwardly,
• an annular piston-forming element having an axially extending tubular stem with a central passageway defined inside a radially inwardly directed inner tube surface,
• the central passageway open at an axial inner end and open at an axial outer end,
• the stem including an annular outlet flexing disc extending radially inwardly from the inner tube surface to a central bore axially through the outlet flexing disc,
• the stem including an annular post sealing disc extending radially inwardly from the inner tube surface to a central bore axially through the post sealing disc, the post sealing disc carried on the stem at a location spaced axially outwardly from the outlet flexing disc,
• the annular piston-forming element coaxially slidably received in the annular compartment for reciprocal movement between a retracted position and an extended position, with:
• (a) the chamber wall radially outwardly of the piston-forming element, and (b) the post member received coaxially within the central passageway passing through the central bore of the outlet flexing disc and the central bore of the post sealing disc,
• engagement between the piston-forming element and the chamber wall preventing fluid flow therebetween axially outwardly and inwardly,
• the outlet flexing disc about the central bore of the outlet flexing disc engaging the post side surface circumferentially thereabout axially inwardly of the transfer port preventing fluid flow axially inwardly between the outlet flexing disc and the post side surface but permitting fluid flow axially outwardly between the outlet flexing disc and the post side surface,
• the post sealing disc about the central bore of the post sealing disc engaging the post side surface circumferentially thereabout axially outwardly of the transfer port preventing fluid flow axially outwardly and inwardly between the post sealing disc and the post side surface,
• a first compartment defined between the piston chamber-forming member and the piston-forming element annularly about the post member inwardly of the engagement between the piston-forming element and the chamber wall and inwardly the outlet flexing disc, the first compartment having a volume that decreases with sliding of the piston-forming element inwardly relative the piston chamber-forming member and increases with sliding of the piston-forming element outwardly relative the piston chamber-forming member,
• a second compartment defined within the central passageway annularly about the post member radially between the radially outwardly directed post side surface and the radially inwardly directed inner tube surface and axially between the outlet flexing disc and the post sealing disc,
• wherein sliding of the piston-forming element inwardly relative the piston chamber-forming member reduces the volume of the first compartment with the one-way valve preventing fluid flow from the first compartment to the source of fluid, the engagement between the piston-forming element and the chamber wall preventing fluid flow therebetween outwardly from the first compartment whereby fluid is forced to pass outwardly between the outlet flexing disc and the post member into the second compartment and from the second compartment via the transfer port into the center passage and via the central passage to out the discharge outlet,
• wherein sliding of the piston-forming element outwardly relative the piston chamber-forming member increases the volume of first compartment drawing fluid through the one-way valve from the source of fluid into the first compartment, with the engagement between the piston-forming element and the chamber wall preventing fluid flow therebetween into the first compartment and the outlet flexing disc engaging the post member to prevent fluid flow axially therebetween axially inwardly into the first compartment from the second compartment.

A fluid pump comprising:

• a piston chamber-forming member defining a chamber about a chamber axis, the chamber having a radially inwardly directed chamber wall, an inner inlet end and an outer open outlet end, the inner inlet end including an inner end wall,
• the inlet end of the chamber having an inlet opening in communication with a source of fluid,
• the piston chamber-forming member including a center post member extending from the inner end wall along the axis coaxially of the chamber outwardly from an axially inner end of the post member to a distal axially outer end of the post member whereby an annular compartment is defined within the chamber between the chamber wall and the post member,
• the post member having an outer w all coaxial about the axis with a radially outwardly directed post side surface,
• the post member having an axially inner portion and an axially outer portion axially outwardly from the inner portion, the axially inner portion located axially inwardly from the axially outer portion,
• the outer wall over the axially inner portion having a diameter, the outer wall over the axially outer portion having a diameter less than the diameter of the inner portion,
• a center passage provided coaxially within the outer wall of the post member, the center passage open at a discharge outlet, the center passage extending axially inwardly from the discharge outlet to a closed axially inner end,
• a transfer port radially through the outer wall of the post member in the outer portion of the post member providing communication between the center passage and the annular compartment through the outer wall,
• an annular piston-forming element having an axially extending tubular stem with a central passageway defined inside a radially inwardly directed inner tube surface,
• the central passageway open at an axial inner end and open at an axial outer end,
• the stem including an annular inlet flexing disc extending radially inwardly from the inner tube surface to a central bore axially through the inlet flexing disc,
• the stem including an annular outlet flexing disc extending radially inwardly from the inner tube surface to a central bore axially through the outlet flexing disc, the outlet flexing disc carried on the stem at a location spaced axially outwardly from the inlet flexing disc,
• the stem including an annular post sealing disc extending radially inwardly from the inner tube surface to a central bore axially through the post sealing disc, the post sealing disc carried on the stem at a location spaced axially outwardly from the outlet flexing disc,
• the annular piston-forming element coaxially slidably received in the annular compartment for reciprocal movement between a retracted position and an extended position, with:
• (a) the chamber w all radially outwardly of the piston-forming element,
• (b) the post member received coaxially within the central passageway passing through the central bore of the inlet flexing disc, the central bore of the outlet flexing disc and the central bore of the post sealing disc,
• (c) engagement between the piston-forming element and the chamber wall preventing fluid flow axially therebetween outwardly and inwardly,
• (d) the inlet flexing disc about the central bore of the inlet flexing disc engaging the post side surface of the axially inner portion of the post member circumferentially thereabout preventing fluid flow axially inwardly between the inlet flexing disc and the post side surface but permitting fluid flow axially outwardly between the inlet flexing disc and the post side surface,
• (e) the outlet flexing disc about the central bore of the outlet flexing disc engaging the post side surface of the axially outer portion of the post member circumferentially thereabout axially inwardly of the transfer port preventing fluid flow axially inwardly between the outlet flexing disc and the post side surface but permitting fluid flow axially outwardly between the outlet flexing disc and the post side surface,
• (f) the post sealing disc about the central bore of the post sealing disc engaging the post side surface of the axially outer portion of the post member circumferentially thereabout axially outwardly of the transfer port preventing fluid flow axially outwardly and inwardly between the post sealing disc and the post side surface, wherein
• (g) a first compartment is defined within the central passageway annularly about the post member radially between the radially outwardly directed post side surface and the radially inwardly directed inner tube surface and axially between the inlet flexing disc and the outlet flexing disc, the first compartment having a volume that decreases with sliding of the piston-forming element inwardly relative the piston chamber-forming member and increases with sliding of the piston-forming element outwardly relative the piston chamber-forming member,
• (h) a second compartment is defined within the central passageway annularly about the post member radially between the radially outwardly directed post side surface and the radially inwardly directed inner tube surface and axially between the outlet flexing disc and the post sealing disc,
• (i) sliding of the piston-forming element inwardly relative the piston chamber-forming member reduces the volume of first compartment with the inlet flexing disc preventing fluid flow from the first compartment to the source of fluid, and fluid is forced to pass outwardly between the outlet flexing disc and the post member into the second compartment and from the second compartment via the transfer port into the central passage and via the central passage to out the discharge outlet,
• (j) sliding of the piston-forming element outwardly relative the piston chamber-forming member increases the volume of first compartment drawing fluid axially outwardly between the inlet flexing disc and the post member from the source of fluid into the first compartment, with the engagement between the piston-forming element and the chamber wall preventing fluid flow axially therebetween and the inlet flexing disc engaging the post member to prevent fluid flow therebetween axially inwardly.