Top-loaded pressure operated container for dispensing viscous products

Claim 2

A piston for a pressurized container having a viscous product and provided with a dispensing valve, said piston comprising a piston body portion of a generally tubular configuration and a resilient annular elastomeric flange provided with an upstanding skirt portion on the outer wall of said piston body portion, said piston body portion being radially spaced from the inner wall of said skirt portion, said upstanding skirt portion being for contact with a container wall and being the only means of piston support, said skirt portion being relatively thin with respect to the space between said skirt portion and the piston body portion, said skirt portion having a large surface area of substantial axial length; whereby, when said piston is inserted in a suitable container and when the space within said skirt portion and above said piston is loaded with viscous product and the space beneath said skirt portion and piston is subjected to a predetermined charge of gas under pressure, said skirt portion will be pressure-loaded into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 3

A piston as claimed in claim 1, wherein said piston body portion includes reinforcement means whereby said piston body portion is relatively stiff in relation to the resilience of said skirt portion.

Claim 4

A piston as claimed in claim 1, wherein the thickness of said skirt portion is in the range of 0.005 to 0.015 inch.

Claim 5

A piston as claimed in claim 1, wherein said skirt portion is integrally formed with said piston body portion.

Claim 6

A piston as claimed in claim 1, wherein said piston body is constituted of a plastic.

Claim 7

A piston as claimed in claim 1, wherein said resilient flange projects radially outwardly and axially toward the head end of said piston body portion.

Claim 8

A piston for a pressurized container having a viscous product and provided with a dispensing valve, said piston comprising a piston body portion of a generally tubular configuratIon, a first resilient annular elastomeric flange provided with an upstanding skirt portion on the outer wall of said piston body portion, a second resilient annular elastomeric flange provided with a skirt portion on the outer wall of said piston body portion and axially beneath said first flange, said piston body portion being radially spaced from the inner walls of said skirt portions, said skirt portions being for contact with a container wall and being the only means of piston support, said skirt portions being relatively thin with respect to the space between said skirt portions and the piston body portion, said skirt portions each having a large surface area of substantial axial length; whereby, when said piston is inserted in a suitable container and when the space within said first skirt portion and above said piston is loaded with viscous product and the space beneath said second skirt portion and piston is subjected to a predetermined charge of gas under pressure, said skirt portions will be pressure-loaded into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 9

A piston for a pressurized container having a viscous product and provided with a dispensing valve, said piston comprising a piston body portion of a generally tubular configuratIon, a first resilient annular elastomeric flange provided with an upstanding skirt portion on the outer wall of said piston body portion, a second resilient annular elastomeric flange provided with a skirt portion on the outer wall of said piston body portion and axially beneath said first flange, said piston body portion being radially spaced from the inner walls of said skirt portions, said skirt portions being for contact with a container wall and being the only means of piston support, said skirt portions being relatively thin with respect to the space between said skirt portions and the piston body portion, said skirt portions each having a large surface area of substantial axial length; whereby, when said piston is inserted in a suitable container and when the space within said first skirt portion and above said piston is loaded with viscous product and the space beneath said second skirt portion and piston is subjected to a predetermined charge of gas under pressure, said skirt portions will be pressure-loaded into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 10

A piston as claimed in claim 7, wherein said second flange projects axially downwardly and radially outwardly from said outer wall to a location axially spaced from the location of said first annular flange.

Claim 11

In combination, a pressure container comprising an elongate cylindrical body with a closed upper end, dispensing-valve means in said upper end, a piston having a closed upper end and integral body structure extending downwardly within a cylinder spaced from the container wall and united to the closed end of said piston, a peripherally continuous axially upwardly directed flexible tubular elastomeric flange carried by said piston within the annular space between the piston body structure and the container wall and of axial extent substantially less than that of said piston, said flange being relatively thin with respect to the space between said tubular flange and the piston body having a periphery of substantially the inner wall-surface peripheral extent of the container body, with a substantial axially extensive area of circumferential flange-seal contact with the container wall by reason of the tubular structure of said flange, said tubular flange being the only means of piston suspension with respect to the container wall, whereby a product chamber is defined in the container space between the flanged piston and the valved end of the container, a viscous product in said product chamber, pressure-sealing means closing the lower end of said container to define a pressure chamber beneath said piston, and a predetermined charge of gas under pressure in the pressure chamber, whereby viscous product pressure loads said tubular flange into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 12

In combination, a pressure container comprising an elongate cylindrical body with a closed upper end, dispensing-valve means in said upper end, a piston having a closed upper end and integral body structure extending downwardly within a cylinder spaced from the container wall and united to the closed end of said piston, a peripherally continuous axially upwardly directed flexible tubular elastomeric flange carried by said piston within the annular space between the piston body structure and the container wall and of axial extent substantially less than that of said piston, said flange being relatively thin with respect to the space between said tubular flange and the piston body having a periphery of substantially the inner wall-surface peripheral extent of the container body, with a substantial axially extensive area of circumferential flange-seal contact with the container wall by reason of the tubular structure of said flange, said tubular flange being the only means of piston suspension with respect to the container wall, whereby a product chamber is defined in the container space between the flanged piston and the valved end of the container, a viscous product in said product chamber, pressure-sealing means closing the lower end of said container to define a pressure chamber beneath said piston, and a predetermined charge of gas under pressure in the pressure chamber, whereby viscous product pressure loads said tubular flange into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 13

The combination of claim 9, in which said container body has a top opening, said dispensing-valve means being assembled to said body at the top opening after dispensable product is loaded through the opening.

Claim 14

The combination of claim 9, in which the radial offset of said tubular flange from said body structure is substantially ten percent of the outer radius of said tubular flange.

Claim 15

The combination of claim 9, in which said closed upper end of said container is a conical reduction from said cylindrical body to a central valve-locating opening.

Claim 16

The combination of claim 12, in which said valve means comprises a resilient bushing having a central body and an integral conical flange generally conforming to the inner surface of the conical reduction of the container and peripherally continuously sealing said bushing to the container, and a headed dispensing-valve member having a stem portion extending through said bushing and located thereby.

Claim 17

The combination of claim 9, wherein said piston body and tubular flange are parts of the same single injection-molded plastic article, the wall thicknEss of the closed end of said piston being substantially greater than that of said tubular flange.

Claim 18

The combination of claim 14, wherein said piston body comprises a cylindrical sheath with internal elongate stiffening ribs at angularly spaced locations.

Claim 19

The combination of claim 9, wherein the upper wall-surface contour of the closed end of said piston includes an outer frusto-conical annulus of slope conforming to that of said conical reduction.

Claim 20

The combination of claim 16, in which said tubular flange is connected to said piston body near the upper end thereof, said tubular flange being of effective axial length less than one half the overall axial length of said piston, and the upper edge of said flange being at substantially the elevation at which the geometrical projection of the slope of the frusto-conical annulus intersects the cylinder defined by the outer surface of said tubular flange.

Claim 21

The combination of claim 9, wherein the portion of said valve means exposed internally of said container is characterized by a central convex spherical contour, and wherein the upper surface of the closed end of said piston is characterized by a central spherical concavity substantially matching the said convex contour.

Claim 22

The combination of claim 9, in which the peripheral extent of said tubular flange is slightly less than that of the adjacent cylindrical container-body wall surface, the material of said flange being sufficiently flexible to inflate into peripherally continuous container-wall contact in response to piston-loading of product by reason of super-atmospheric pressure in said pressure chamber.

Claim 23

In combination, a pressure container comprising an elongate cylindrical body with a closed upper end, dispensing-valve means in said upper end, a piston having a closed upper end and integral body structure extending downwardly within a cylinder spaced from the container wall and united to the closed end of said piston, a peripherally continuous axially upwardly directed flexible tubular elastomeric flange carried by said piston within the annular space between the piston body structure and the container wall, said flange being relatively thin with respect to the space between said piston body and the container wall and being the only means of piston suspension with respect to the container wall, said flange having a periphery of substantially the inner wall-surface peripheral extent of the container body and being of substantial axial extent which is substantially less than that of said piston body structure, whereby a product chamber is defined in the container space between the flanged piston and the valved end of the container, a viscous product in said product chamber, pressure-sealing means closing the lower end of said container to define a pressure chamber beneath said piston, and a predetermined charge of gas under pressure in the pressure chamber, whereby viscous product pressure-loads said tubular flange into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 24

In combination, a pressure container comprising an elongate cylindrical body with a closed upper end, dispensing-valve means in said upper end, a piston having a closed upper end and integral body structure extending downwardly within a cylinder spaced from the container wall and united to the closed end of said piston, a peripherally continuous axially upwardly directed flexible tubular elastomeric flange carried by said piston within the annular space between the piston body structure and the container wall, said flange being relatively thin with respect to the space between said piston body and the container wall and being the only means of piston suspension with respect to the container wall, said flange having a periphery of substantially the inner wall-surface peripheral extent of the container body and being of substantial axial extent which is substantially less than that of said piston body structure, whereby a product chamber is defined in the container space between the flanged piston and the valved end of the container, a viscous product in said product chamber, pressure-sealing means closing the lower end of said container to define a pressure chamber beneath said piston, and a predetermined charge of gas under pressure in the pressure chamber, whereby viscous product pressure-loads said tubular flange into peripheral and axially continuous light sealing and stabilizing contact with the container wall.

Claim 25

A piston for a top-loaded pressurized container having above said piston a viscous product and a dispensing valve, and a gaseous propellant at super-atmospheric pressure beneath said piston, said piston comprising a piston-body portion of generally tubular configuration and a resilient annular elastomeric flange provided with an upwardly directed skirt portion which projects upwardly and outwardly relative to the outer vertical wall of the piston body, said piston body being spaced from the inner wall of said container and non-sealing therewith and said flange skirt portion being the only means of piston-body suspension with respect to the inner wall of said container, the included effective transverse sectional area of said piston body substantially exceeding the included effective transverse sectional area of said space between said piston body and the inner wall of the container, said skirt portion having a sUbstantial axially extensive surface area and being of such a length that substantially the total portion of said surface area when the piston body is inserted in said container engages the inner wall of said container with a light sealing pressure by the force exerted by said gaseous propellant acting on the piston body and thereby transmitting the predominant fraction of said force to compressionally load the viscous product and, hence, said skirt into radially outward sealing contact with the inner wall of said container.

Claim 26

A piston for a top-loaded pressurized container having above said piston a viscous product and a dispensing valve, and a gaseous propellant at super-atmospheric pressure beneath said piston, said piston comprising a piston-body portion of generally tubular configuration and a resilient annular elastomeric flange provided with an upwardly directed skirt portion which projects upwardly and outwardly relative to the outer vertical wall of the piston body, said piston body being spaced from the inner wall of said container and non-sealing therewith and said flange skirt portion being the only means of piston-body suspension with respect to the inner wall of said container, the included effective transverse sectional area of said piston body substantially exceeding the included effective transverse sectional area of said space between said piston body and the inner wall of the container, said skirt portion having a sUbstantial axially extensive surface area and being of such a length that substantially the total portion of said surface area when the piston body is inserted in said container engages the inner wall of said container with a light sealing pressure by the force exerted by said gaseous propellant acting on the piston body and thereby transmitting the predominant fraction of said force to compressionally load the viscous product and, hence, said skirt into radially outward sealing contact with the inner wall of said container.