Mouth cavity irrigation unit

A mouth cavity irrigation device comprising a main body ( 10 ) and an elongate, generally tubular reservoir ( 12 ) removably connected thereto, to provide a handle member. The reservoir holds a quantity of fluid ( 14 ), such as water, and can be removed from the main body ( 10 ) so as to be cleaned or emptied of or filled with liquid. The main body ( 10 ) has an outlet ( 16 ) to which is removably and rotatably connected an elongate, generally frusto-conical nozzle ( 18 ) having a generally central channel ( 19 ) which runs from an inlet ( 21 ) to a relatively narrower outlet ( 24 ). A manually-operated pump ( 26 ) is housed within the main body ( 10 ) and a dip tube ( 28 ) is connected at one end to a stepped cylinder ( 29 ) forming part of the pump ( 26 ), the other end of the dip tube ( 28 ) extending into the reservoir ( 12 ). A manually operable button ( 41 ) which activates the arrangement is provided on the outer wall of the main body ( 10 ).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 of he drawings, a mouth cavity irrigation device according to a first embodiment of the present invention comprises a main body 10 and an elongate, generally tubular reservoir 12 removably connected thereto, by, for example, a bayonet fitting, to provide a handle member. The reservoir holds a quantity of fluid 14 , such as water, and can be removed from the main body 10 so as to be cleaned or emptied of or filled with liquid. The main body 10 has an outlet 16 to which is removably and rotatably connected, by means of, for example, a push-fit arrangement, an elongate, generally frusto-conical nozzle 18 having a generally central channel 19 which runs from an inlet 21 to a relatively narrower outlet 24 . In this exemplary embodiment of the invention, the outlet 16 of the main body 10 is disposed at an angle to the vertical axis 20 of the main body 10 and, in this case, the reservoir 12 so that the nozzle 18 , when connected to the main body is also disposed at an angle to the vertical axis 20 . The angle in this case is around 45°, but may be any convenient angle. The nozzle 18 is curved or bent (at 22 ) close to its outlet 24 . It should be noted that the main body 10 and the reservoir 12 may also be at an angle to each other. A manually-operated pump 26 is housed within the main body 10 and a dip tube 28 is connected at one end to a stepped cylinder 29 forming part of the pump 26 , the other end of the dip tube 28 extending into the reservoir 12 . Space is also provided in the reservoir 12 to store one or more spare or additional nozzles 40 , when the device is not in use and (preferably) when the reservoir 12 is empty of liquid but connected to the main body 10 . The pump 26 comprises a stepped cylinder 29 , closed at one end and having an inlet (connected to the dip tube 28 ). The diameter of the cylinder 29 is narrower at the closed end, as shown. The wider, open end of the cylinder 29 is provided with a piston 36 , the outer circumference of which is in substantially fluid-tight, slidable engagement with the inner surface of the cylinder 29 . Operation of the pump 26 is effected by an arrangement 30 comprising a tube 32 which is in fluid communication with the channel 19 in the nozzle 18 via a resiliently flexible tube 34 connected at or adjacent one end of the tube 32 . The tube 32 extends through an opening in the piston 36 into the cylinder 29 , the end 33 of the tube 32 which extends into the cylinder 29 being smaller than the rest to locate with a spring (see FIG. 1A ). A manually operable button 41 which activates the arrangement 30 is provided on the outer wall of the main body 10 . In use, the reservoir 12 is first filled with, for example, water 14 up to a line or marking 15 indicating the maximum fluid level. For example, the reservoir 12 may be required to be filled up to a maximum of 37.5 mL. The reservoir 12 is then connected to the main body 10 , and the nozzle 18 is connected to the outlet 16 of the main body 10 , and rotated relative thereto, as required, to obtain the desired angle of the nozzle 18 relative to the device. The device can be held in the right or left hand as required. In order to prime the pump 26 for use, the dip tube 28 and stepped cylinder 29 must first be filled with water. When the button 41 is pressed, the arrangement, consisting of the pipe 32 and the piston 36 , extends further into the cylinder 29 , until the piston 36 reaches the “step” at which the cylinder 29 narrows, and the smaller diameter 33 of the tube 32 extends into the section of the cylinder denoted 29 a . Within the section of the cylinder denoted 29 a there is provided a spring 100 ( FIG. 1A ) which is compressed as the smaller diameter end 33 of the tube 32 extends towards and into the cylinder section 29 a . There is an inlet valve 102 ( FIG. 1A ) between the dip tube 28 and the cylinder 29 , which is initially closed. Thus, by pressing the button 41 , the pressure in the cylinder is increased. When the button 41 is released, the spring (not shown) in the cylinder section 29 a expands, pushing the tube 32 and the piston 36 back to their initial positions and thereby decreasing the pressure in the cylinder 29 . This action causes the inlet valve to open and water to flow up the dip tube 28 and into the cylinder 29 , until the pressure differential between the reservoir 12 and the cylinder 29 is equalised, at which point the inlet valve closes. Once the dip tube 28 and cylinder 29 are filled with water, the device is ready for use. In use, the user presses the button 41 , causing the narrow diameter end 33 of the tube 32 to extend further into the stepped cylinder 29 , so as to reduce the size of the cylinder 29 , and subsequently into the cylinder section 29 a , thereby forcing the water held therein into the tube 32 . An outlet valve 104 ( FIG. 1A ) may be provided in the tube 32 , between the tube 32 and the flexible tube 34 , or even outside the pump in, for example, the flexible tube 34 itself. The outlet valve 104 may be a ball valve comprising a ball which closes against a seating when there is negative pressure at 29 . In an alternative embodiment, the outlet valve may be a sleeve valve whereby an aperture is provided close to the small diameter end of the tube 32 , the aperture being closed by the piston when the device is not in use. When the button 41 is pressed, there is relative movement between the tube 32 and the piston whereby the tube 32 slides through the piston, exposing the aperture and allowing fluid to flow therethrough. Water flows up the tube 32 , the outlet valve opens and the water flows through the tube 32 , through the flexible tube 34 , into the channel 19 and out through the nozzle 24 in the form of a jet into the mouth cavity. Once all of the pressurised water from the cylinder 29 has been released, the button 41 is released, the outlet valve closes and the tube 32 and piston 36 return to their initial positions, reducing the pressure in the cylinder 29 and drawing more water from the reservoir 12 up through the dip tube 28 and into the cylinder 29 , as described above. Thus, once the pump has been primed, each time the button 40 is pressed all the way in to give a “full” stroke, a predetermined fixed volume of water is ejected from the nozzle outlet 24 into the mouth cavity. If, for example, the reservoir 12 holds 37.5 mL of water, the device could be arranged to dispense 50 doses of 0.75 mL each, after which the reservoir would need to be refilled. It is likely that a complete operation would require several activations (i.e. pushes) of the pump 26 . It should be noted that the user also has the option to operate the unit using partial strokes or pushes of the button so that less than the predetermined fixed volume of water is dispensed. The user may also have the option to vary the rate or frequency at which the button is pushed. These options provide the user with substantially more control over the flow rate than prior art devices. In another exemplary embodiment of the invention, the water to be discharged from the device could be initially pressurised by, for example, a spring activated piston, and water output could be controlled by means of a valve or the like, controllable by the user. Water discharge could then be continuous or intermittent, as desired. Referring to FIG. 2 of the drawings, a mouth cavity irrigation device according to a second embodiment of the invention, is substantially the same in all respects to the exemplary embodiment described with reference to FIG. 1 , except that the outlet 16 of the main body 10 is not disposed at an angle to the vertical axis 20 of the main body, and instead the nozzle 18 extends upwardly from the main body 10 , substantially in line therewith. Referring to FIG. 3 of the drawings, a mouth cavity irrigation device according to a third exemplary embodiment of the invention is similar in many respects to the first and second exemplary embodiments described above. In this case, however the main body 10 and the reservoir 12 are both generally cylindrical (although other shapes are envisaged) and are connected together to provide a relatively narrow, elongate structure, with the nozzle 18 removably connected to a nozzle holder which is removably connected at the top of the main body as shown. The nozzle holder 18 a is rotatable (about a substantially vertical axis) relative to the main body 10 and the nozzle 18 , which is disposed at an approximately 20° angle thereto, is rotatable relative to the nozzle holder 18 a . It will be appreciated that any convenient nozzle angle (including 0°) is intended to be encompassed by the invention. The pump 26 is once again a generally elongate structure comprising a cylinder 29 , an inlet and an outlet, but the pump 26 is somewhat different so as to substantially reduce the diameter of the device required to accommodate it. Referring in particular to FIG. 3 A, the structure and operation of the pump 26 in the third exemplary embodiment is substantially the same as that described with reference to the first exemplary embodiment, except that the tube 32 ( FIG. 1 ) is replaced by a solid member 132 which pushes the piston 36 into the cylinder 29 when the button is pressed. The outlet and outlet valve 133 (connected to the tube 34 leading to the nozzle 18 ) is provided for the cylinder 29 , and (in the arrangement shown) diametrically opposite the inlet and inlet valve 134 . Embodiments of the invention have been described above by way of examples only and it will be apparent to persons skilled in the art that modifications and variations can be made to the described embodiments without departing from the scope of the invention.