Liquid droplet interproximal cleaning apparatus with gas stream protection

This invention relates generally to interproximal (interdental) cleaning apparatus/appliances, and more particularly concerns such an apparatus designed to protect against unsafe increases in gas stream and/or liquid droplet flow due to orientation of the apparatus in use.

Liquid droplet interproximal (interdental) cleaning apparatus/appliances use a CO 2 or other gas stream to accelerate a volume of liquid and to produce liquid droplets therefrom, which are directed to the dental regions for cleaning. A CO 2 gas stream is typically produced by the rapid expansion of a small amount of gaseous CO 2 released from a CO 2 reservoir, such as a cartridge.

The CO 2 reservoir will typically include both liquid CO 2 and gaseous CO 2 . Typically, only gaseous CO 2 proceeds from the reservoir when the apparatus is in an upright orientation. The gaseous CO 2 is directed into and then exits from a metered valve to form a gas stream.

A portion of the gas stream may be used to accelerate liquid from the reservoir into the gas stream to produce liquid droplets. However, when the apparatus is tilted, including below horizontal or even completely upside down, liquid CO 2 enters the metered valve instead of gaseous CO 2 , which results in a significant increase in the amount of gas from the metered valve as the gas decompresses prior to and at the exit of the valve. This can result in the speed of the modified gas stream being excessive and/or the fluid being accelerated at a too high a rate, resulting ultimately in damage to the gingival or interproximal pockets of the dental region.

Hence, it is desirable to have a structural arrangement which protects against increases in the decompressing (expanding) gas from the gas reservoir, regardless of the orientation of the apparatus.

Accordingly, an interdental cleaning apparatus is described herein, comprising: a compressed gas reservoir, containing liquid compressed gas and gaseous compressed gas; a liquid reservoir; a system for moving liquid in the liquid reservoir out of the liquid reservoir and into contact with an output gaseous stream of gas from the decompression of gas from the gas reservoir, resulting in a stream of fluid droplets which can be directed from the apparatus toward the dental regions of a user for cleaning thereof; and a metering valve and a siphon tube extending from the metering valve to the gas reservoir, wherein the metering valve has such a metered volume that the output of gaseous gas resulting from the decompression of gas from the gas reservoir will not damage the dental regions of the user, regardless of the orientation of the apparatus in use.

The drawing is a schematic view of a liquid droplet dental cleaning apparatus, incorporating the gas limiting system described herein.

The FIGURE shows in general a fluid droplet interproximal cleaning apparatus, generally at 10 . In the embodiment shown, the apparatus includes a gas reservoir 12 , which can be in the form of a CO 2 cartridge. The CO 2 cartridge will typically include both liquid CO 2 , shown at 14 , and gaseous CO 2 , shown at 16 , for example. Connecting the reservoir 12 to a metering valve 18 is a siphon tube 20 , which is described in more detail below.

The metering valve is operated by a control button or similar element 24 , which allows a selected amount of CO 2 into a gas chamber 26 . The selected amount of gas will typically be appropriate for a single use, for example in the range of 0.01 ml. Extending from gas chamber 26 and forming a part of a nozzle for the apparatus is a gas streaming line 28 , which terminates in an exit orifice 30 .

The interdental cleaner also includes a reservoir for liquid 34 , which could be water or some other solution, including mouthwash or various oral care treatment solutions. Pump 38 moves liquid through a connecting tube 36 from reservoir 34 to a one-way valve 40 and then to a liquid chamber 42 . Liquid chamber 42 is adapted to contain a single use of liquid, which in the embodiment shown is approximately 0.1 ml.

A one-way valve 44 connects gas chamber 26 to liquid chamber 42 . A liquid line 46 extends from liquid chamber 42 and delivers liquid to gas line 28 , near the exit orifice 30 in the embodiment shown.

In operation, the expanding gas from the gas reservoir will create sufficient pressure in gas chamber 26 to open one-way valve 44 . Gas enters chamber 42 and acts on the liquid therein, accelerating the liquid through liquid line 46 to the gas stream in the gas line 28 . Typically, only a small amount of gas is necessary to produce this liquid acceleration effect.

When the accelerated liquid comes into contact with the gas stream, liquid droplets are produced in a desired size range and with a desired velocity, such as 10 microns in diameter, with a velocity of 60 mls. The stream of fluid droplets ( 31 ) proceeds through the exit orifice 30 to the dental region to be cleaned, such as the interproximal areas of the teeth.

Siphon tube 20 extends down into gas reservoir 12 a sufficient distance (usually a short distance from the bottom) that only liquid CO 2 (or other gas) can enter metering valve 18 when the apparatus is in an upright orientation. The size of the metering valve is such as to accommodate a single use of CO 2 from the reservoir (as it expands) when the CO 2 from the reservoir is in a liquid state. When the apparatus is tilted or used upside down, however, CO 2 in a gaseous state will now enter the siphon tube, instead of liquid CO 2 , since the upper end of the gas reservoir, where the siphon tube terminates, contains gaseous CO 2 . This will result in a smaller amount of CO 2 in the metering valve and the gas chamber because of the lower density of gaseous CO 2 compared to liquid CO 2 , i.e. CO 2 will expand less when the CO 2 from the reservoir is in a compressed gaseous state than when it is in a compressed liquid state.

The arrangement of the siphon tube and the volume of the metering valve is such that in normal upright operation, liquid CO 2 having a volume of the metering valve results in the correct amount of CO 2 gas to produce an effective single use of the cleaning apparatus, while in a tilted or upside down position, a lesser volume of CO 2 gas is produced since the gas from the reservoir is in a gaseous state already. This lower volume of CO 2 gas, due to the small volume of the metering valve, ensures the safety of operation of the apparatus, regardless of the orientation of the apparatus.

However, the siphon tube 20 will function as a small reservoir when the apparatus is upside down, resulting in several rapid bursts or shots of CO 2 in succession, as the gaseous CO 2 moves into the metering valve, in order to accomplish the desired cleaning action, but without any risk of excessive gas stream or liquid droplet velocity.

Hence, the siphon tube and the valve are configured and arranged so that a tilted or upside down orientation will not result in an increase of CO 2 gas stream output beyond a safe level, for instance, the level of CO 2 output when the apparatus is in an upright position. This safety arrangement involves both the dimensions and position of the siphon tube in the gas reservoir and the volume of the metering valve, which is set to that volume associated with safe gas stream characteristics for the liquid CO 2 from the gas reservoir and its resulting expansion as it is released from the reservoir.

Accordingly, a fluid droplet interdental cleaning arrangement has been described which provides protection for the user, regardless of the orientation of the apparatus.

Although a preferred embodiment of the invention has been disclosed for the purposes of illustration, it should be understood that various changes, modifications and substitutions may be incorporated in the embodiment without departing from the spirit of the invention, which is defined by the claims which follow.