Patent Publication Number: US-6910603-B2

Title: Leak preventing closure in a dispenser pump

Description:
This invention relates to an improved dispenser pump of the kind which, when mounted on a container for a liquid or pasty substance such as soap, will dispense a measured quantity of the substance when the pump is manually actuated. Dispenser pumps of this kind are well known and are to be distinguished from valves for e.g. aerosol sprays which when opened dispense as a result of pressurisation of the container. 
   Fixed spout dispenser pumps have a lower component adapted to be fitted to a container and an upper component rotatable relative to the lower component to bring the spout on the upper component into or out of register with an outlet passage which is stationary with respect to the lower component. The pump itself may take the form of a piston-and-cylinder assembly or it may take the form of a self-restoring, deformable part of the upper component. When this is compressed the internal volume of the upper component is diminished. When it is released and allowed to expand the substance in the container is sucked into the upper component through a first one-way valve. When the deformable part of the upper component is depressed a second time the substance it contains is expelled through the spout through a second one-way valve. When allowed to expand again the upper component sucks a second, measured quantity of the substance into its interior ready to be dispensed. 
   The pump will of course only dispense if the spout is aligned with the outlet passage, enabling the pump to be “closed” e.g. during transport and storage. However to prevent leakage if the pump is accidentally depressed while “closed” it has been found necessary to incorporate a locking feature which mechanically prevents actuation of the pump when the outlet passage is not aligned with the spout. 
   The danger of leakage is increased by the fact that in addition to the outlet passage and spout it is necessary to provide a second path through the dispenser pump between ambient air and the interior of the container. Unless air can enter the container to replace the substance sucked out of it the pump will not work. Therefore an air passage has been provided through the lower component which registers with an air hole in the upper component only when the outlet passage is in register with the spout. EP-A-0 274 877 exemplifies such an arrangement in which the orifices of the outlet passage and air passage of the lower component have a circumferential separation around the cylindrical outer surface of the lower component which is equal to the circumferential separation of the spout and the air hole on the cylindrical inner surface of the upper component, the cylindrical surfaces sliding relative to one-another as the upper component is rotated and providing the closure of the outlet and air passages when the spout is taken out of alignment with the outlet passage. If the pump is subjected to sufficient pressure leakage may occur between the cylindrical surfaces. The substance in the container may migrate between these surfaces from the outlet passage to at least the nearer of the air hole and the spout and it is to prevent this that the mechanical locking feature has been provided. 
   The mechanical locking feature however adds to the complexity of the dispenser pump and is therefore to the cost of its manufacture. An object of the present invention is to obviate the need for the locking feature by providing a more efficient seal when the upper component is rotated to the closed position. 
   In accordance with the present invention there is provided a dispenser pump comprising a lower component adapted to be fitted to a container for a liquid or pasty substance to be dispensed and an upper component rotatable relative to the lower component and having a spout opening and an air opening, the lower component comprising a passageway for communicating the interior of the container, with the interior of the upper component, said passageway controlled by a first non-return valve, an annular discharge compartment of the lower component surrounding said passageway, a second non-return valve permitting discharge of the substance from the interior of the upper component into said discharge compartment while preventing the entry of air to the interior of the upper component from the spout opening and an obturating element integral with the lower component located at and circumferentially interrupting the periphery of said compartment, the arrangement being such that in one angular orientation of the upper relative to the lower component the spout opening and the air opening are obturated by the obturating element while in other angular orientations of the upper component the interior of the upper component can communicate with the spout opening through the discharge chamber and a pathway for air to enter the container provided through the lower component is in communication with said air opening. 
   Preferably said pathway for air includes an annular chamber surrounding said passageway below the discharge compartment and separated therefrom by an annular barrier seal in rubbing contact between the upper and lower components and the spout opening and the air opening are spaced in the direction of the axis of rotation of the upper relative to the lower component such that the spout opening will align with the discharge compartment and the air opening will align with the annular air chamber on opposite sides of said barrier seal. 
   The obturating element may comprise the distal end of an arm circumferentially interrupting the discharge compartment. The obturating element may also comprise the distal end of an arm circumferentially interrupting the air chamber. 
   The said arms may lie in the same plane which contains the axis of rotation and the spout opening the the air opening will also lie in the same plane containing the axis of rotation. 
   In a preferred embodiment of the invention the second non-return valve is in the form of a deflectable member which extends from and surrounds an upper region of said passageway of the lower component, the periphery of said deflectable member making contact with a shoulder of the interior of the upper component which prevents upward but allows downward deflection of the periphery of said deflectable member. 
   Preferably said deflectable member defines the upper end of the discharge compartment. 
   At least the said barrier seal may be of a softer material than the cylindrical component surface with which it is in rubbing contact. The lower component as a whole may be of a softer material than the upper component. 
   The upper component may comprise a top region of a self-restoring concertina configuration whereby the interior volume of the upper component is variable. 

   
     A preferred embodiment of the present invention will now be described with reference to the accompanying drawings, in which: 
       FIG. 1  is a front view of a dispenser pump in accordance with the invention; 
       FIG. 2  is a sectional view taken on the line B—B of  FIG. 1 ; 
       FIG. 3  is a sectional elevation of the dispenser pump taken on the line A—A of  FIG. 1 , and 
       FIG. 4  is a perspective view of the lower component of the dispenser pump in isolation from the upper component. 
   

   The dispenser pump illustrated has an upper component  10  which is rotatable relative to a lower component  11 . Twin annular beads  12  of the lower component snap engage in twin annular grooves on the inner surface of the upper component  10  to permit this rotation, which is limited to just less than 1800 by the abutment of radial arms  13  of the lower component with step formations  14  of the upper component. The upper component  10  has a fixed spout  15  and its top  16  is in the form of a self-restoring concertina bellows. Collapsing pressure on the bellows  16  will reduce the internal volume of the upper component  10  and self-restoration of the bellows  16  will increase it, thus providing the necessary pumping action. 
   The lower component  11  is formed at its lower end with an internal screw thread to engage a container (not shown) for the liquid or pasty substance to be dispensed. It has a central passageway  30  controlled by a non-return valve  19  for communicating the interior of the container with the interior of the upper component  10 . In the example illustrated the valve  19  is a caged ball valve but this could be replaced by a flap valve. In use a tube (not shown) will extend from a downward extension  20  of the passageway  30  to a position near the bottom of the container to ensure that air will not be pumped out of the container at least until its contents are nearly exhausted. 
   An annular discharge compartment  31  of the lower component  11  surrounding its passageway  30  has an upper wall in the form of a second non-return valve  17  and a lower wall the periphery  23  of which makes rubbing contact with the internal surface of the upper component. The second non-return valve  17  is in the form of an annular member surrounding the top end of the passageway  30  which is upwardly dished and is thinned toward its periphery so as to be deflectable. The periphery of the disc  17  contacts a shoulder  18  of the interior of the upper component  10  so that it cannot deflect upwardly (to permit air to enter the interior of the upper component from the spout) but so that it can be, deflected downwardly to allow the substance being dispensed to enter the compartment  31  from the interior of the upper component  10 . 
   To enable air to replace the content of the container as it is pumped out an air opening  22  is provided in the upper component  10  below the spout  15 . The periphery of the lower component  11  has an annular air chamber  32  divided from the discharge compartment  31  by the periphery  23 . At one or more circumferential positions an air hole (not shown) is provided in the radially inner wall of this air chamber  32  to communicate the air opening  22  with the interior of the container. 
   The radial arms  13  interrupt circumferentially both the annular discharge compartment  31  and the annular air chamber  32 , their distal ends being in rubbing contact with the cylindrical inner wall of the upper component  10 . The upper of the two arms  13  shown in  FIG. 2  is provided only for mechanical balance and could be either omitted or perforated, but the distal end of the other arm serves as an obturating element which will close both the inner end opening of the spout  15  and the air opening  22  when the upper component  10  is rotated to the position in which it is shown in  FIGS. 2 and 3 . Resilient pads  21  and  33  may be secured to the distal end of the obturating arm  13  above and below the annular barrier seal provided by the periphery  23  to improve the closure. 
   It is preferable that the lower component  11  is moulded from a softer material than the upper component  10 , in which case the pads  33  and  21  may be unnecessary. 
   To operate the pump the upper component  10  is rotated to a position in which the inner opening of the spout  15  and the air opening  22  are no longer obturated by the arm  13 . The bellows  16  is compressed, expelling air through the spout  15 . When pressure on the bellows  16  is relieved it restores its shape, thereby sucking into its interior the contents of the container through the valve  19 . When the bellows  16  is compressed a second time the valve  19  closes and the content of the interior of the upper component  10  is expelled past the valve  17  into the discharge compartment  31  and thence out through the spout  15 . This process can of course be repeated as often as necessary to dispense the desired quantity of the liquid or paste from the container. 
   The bellows  16  could be replaced by a simple bulb. The improved seals preventing leakage of the content of the upper component  10  in the closed position of the dispenser permits the use of a flexible pump of this kind in place of a more complex and expensive piston-and-cylinder assembly and obviates the need for a mechanical lock preventing actuation of the pump when the dispenser is “closed”.