HK1180934B - Improved dental nozzle - Google Patents

Description

Improved dental nozzle

Technical Field

The present invention relates to a dental device, in particular a dental syringe device having a nozzle tip for providing a jet of air, liquid or a mixture thereof to a patient undergoing a dental treatment.

Dental syringes supplied with air, water or air/water mixtures (also known as three-way syringes) are used to clean the mouth of a patient before and during dental treatment. These dental syringes can be supplied with water or air at high pressure at a specific small area of the mouth.

A typical dental syringe device includes a handpiece to which an air source and a water source (both under pressure) are supplied and which has a nozzle assembly or tip at its operative end. Such nozzle assemblies or nozzle tips comprise a coaxial tube assembly that is secured to the end of a three-way syringe device.

Both the inner and outer tubes of the nozzle tip are made of plastic or metal. Because the inner tube must be supported within the outer tube while allowing flow through the outer tube, the nozzle tip may be relatively expensive to manufacture.

The three-way syringe may also come into contact with the patient's mouth during use, thereby preventing contamination or cross-contamination between the tips of the patient's disposable syringes.

GB2213732 discloses a disposable syringe tip for use on an air/water dental syringe. The disclosed disposable tip can be used on a three-way dental syringe during dental procedures to clean and dry the mouth area of a patient by selectively supplying a jet of water for rinsing, a jet of air for drying, and an atomized spray of water and air. However, the disposable tip should advantageously be used in all types of dental chair. There are also special problems with the increased range of dental chair options available, as are some performance problems. This is particularly true for certain syringes and dental treatment chairs that operate at lower air pressures (about 40 psi) when compared to the more common 60psi air pressure. When such a disposable tip is used in a low pressure treatment chair, it has poor performance in terms of air jet velocity and quality of the resulting atomized spray.

Disclosure of Invention

The object of the present invention is to provide a dental device which has good performance at higher and lower pressures of water and air and which is disposable after each use in order to prevent contamination.

According to a first aspect of the present invention there is provided a dental device comprising a nozzle tip for a three-way syringe device, said nozzle tip comprising a coaxial tube assembly having attachment means for releasably attaching said nozzle tip to a syringe device, and said tube assembly comprising an outer tube and an inner tube, said inner tube having an end portion comprising an inclined outlet face, and the inner tube being a tight fit against an inner surface of the outer tube.

According to a second aspect of the present invention there is provided a nozzle tip for a three-way syringe device, said nozzle tip comprising a coaxial tube assembly having attachment means for releasably attaching said nozzle tip to a syringe device, and said tube assembly comprising an outer tube and an inner tube, said inner tube having an end portion comprising an inclined outlet face, and the inner tube being a tight fit against an inner surface of the outer tube.

With this structure, the nozzle tip can have good performance for air velocity and spray quality when used to supply air or water at various pressures. In particular, the present invention has been found to have good air velocity and atomized water spray performance when used with low pressure feeds. It has been found that this advantageous performance is provided by using a nozzle tip structure having an inner tube and an outer tube, wherein the inner tube has an inclined outlet face.

It is believed that the use of a tight or tight fit of the inner and outer tubes provides a seal of the annular air flow region between the inner and outer tubes at the end portions. This reduction in annular air flow area causes air flow to be forced past and out of the nozzle tip through the angled outlet face.

The nozzle tips can be inexpensively produced so that each nozzle tip can be detached from the syringe device and discarded after use on a single patient. Thus, a new contamination free nozzle tip can be attached to the syringe device for use with the next patient. In this way, the risk of cross-contamination between patients is avoided or at least greatly reduced.

The inner and outer tubes may be individually formed of any suitable material. Suitable materials may include, for example, plastic or metal selected from brass, stainless steel or anodized aluminum. Preferably, the inner and outer tubes may be formed separately from a plastics material. Suitable plastic materials may include, for example, high density polyethylene or polypropylene.

It is contemplated that the outer tube and the inner tube may be manufactured separately, and that the subsequent assembly of the nozzle tip includes inserting the inner tube into the outer tube. Alternatively, the outer tube may be moulded over the inner tube.

The inner tube may be formed such that it is entirely contained within the outer tube. The exposed end of the inner tube may be flush with the exposed end of the outer tube.

The inner tube may comprise a hollow conduit extending along the length of the inner tube. The hollow conduit may be centrally located along the length of the inner tube. The hollow conduit may have an exit point at the exposed end of the syringe.

Preferably, the hollow conduit is a conduit for water. Thus, the conduit may be provided for the flow of water from the end of the tip connected to the syringe along the nozzle tip to the water outlet at the exposed end of the inner tube.

It should be noted that the height of the exposed end of the inner tube represents the dimension from the angled outlet face to the furthest circumferential point of the inner tube (i.e., the furthest point of the outer circumference of the inner tube). The height of the exposed end of the inner tube may be in the range from 2.00mm to 3.20 mm. More preferably, the height may be in the range from 2.40mm to 2.90 mm. More preferably, the height may be in the range from 2.60mm to 2.70 mm.

The inner diameter of the outer tube may be in the range from 3.00mm to 3.50 mm. More preferably, the diameter may be in the range of 3.10mm to 3.40 mm. More preferably, the diameter may be in the range of from 3.20mm to 3.30 mm.

The inner diameter of the outer tube may vary along its length or may be constant. In embodiments where the diameter varies along the length of the outer tube, it will be appreciated that the preferred diameters detailed herein refer to average values.

The diameter of the inner tube may range from 3.00mm to 3.55 mm. More preferably, the diameter may be in the range of from 3.15mm to 3.40 mm. Most preferably, the diameter may be in the range from 3.25mm to 3.35 mm.

The diameter of the inner tube may vary along its length or may be constant. In embodiments where the diameter varies along the length of the inner tube, it will be appreciated that the preferred diameters detailed herein refer to average values.

The exposed end of the inner tube may include a chamfered edge around the perimeter, but not include a beveled exit face.

The inner tube may include a plurality of radially outwardly extending flanges. The flange may be positioned towards the end of the inner tube adjacent the syringe. The flange may have a clearance fit against the inner surface of the outer tube. Alternatively, the flange may be located in a complementary groove provided in the inner surface of the outer tube. Preferably there are four such flanges angularly spaced 90 ° around the outer surface of the inner tube.

The inner tube may also include a plurality of elongated ribs disposed on an outer surface of the inner tube and in contact with an inner surface of the outer tube. The elongated ribs may be disposed along the inner tube. Preferably there are four such elongate ribs angularly spaced 90 ° around the outer surface of the inner tube.

Both the flange and the elongated rib may be used to allow the inner tube to be centrally located within the outer tube during manufacture and also to continue to hold the inner tube in place during shipping, storage and use.

The inner tube may have an end portion arranged towards the exposed end of the nozzle. The diameter of this end portion of the inner tube may be larger than the diameter of the rest of the inner tube, thereby providing an enlarged inner tube end portion.

The enlarged end portion of the inner tube may provide a tight fit for the end portion against the inner surface of the outer tube.

The enlarged end portion of the inner tube may have a length in the range from 1mm to 4 mm. More preferably, the length may be in the range from 1.5mm to 3 mm. Most preferably, the length may be in the range from 1.7mm to 2.5 mm.

The enlarged end portion may include a reduced diameter portion to provide a stepped enlarged end portion. The reduced diameter portion is preferably disposed adjacent the outlet face of the inner tube. The reduced diameter portion may comprise up to about half of the enlarged end portion of the inner tube. The reduced diameter portion makes the inner tube easier to assemble with the outer tube.

The distance between the outer surface of the end portion of the inner tube and the inner surface of the outer tube may determine the radial gap. The radial gap may be calculated by subtracting the diameter of the end portion of the inner tube from the outer tube. The radial gap may be in the range from 0.10mm to-0.20 mm. More preferably, the gap may be in the range of from 0.07mm to-0.17 mm. Most preferably, the distance may be in the range of from 0.05mm to-0.15 mm.

Thus, the radial gap may provide an interference fit between the end portion of the inner tube and the outer tube, which indicates that the radial gap value is negative.

It can also be seen that the radial clearance between the outer and inner tubes around the inclined outlet face will be greater than the radial clearance around the inclined outlet of the inner tube. Thus, the tight fit of the inner and outer tubes may be maintained around only the end portion of the inner tube where the inner surface of the outer tube is in tight contact with the outer surface of the inner tube.

The end portion of the inner tube includes an inclined outlet face. The angled exit face may be formed by an angled cut. The oblique cut may be arranged such that the size of the end portion of the inner tube decreases towards the exposed end.

The angled outlet face may provide a partial circular cross-section at the exposed end of the inner tube.

The angled outlet face may have an oblique angle that is the angle at which the angled outlet face is angled from the beginning of the portion toward the exposed end of the inner tube and relative to a horizontal axis. The bevel angle may range from 3.00 ° to 7.00 °. More preferably, the bevel angle may be in the range of from 4.00 ° to 6.00 °. Most preferably, the bevel angle may be in the range from 4.50 ° to 5.60 °.

It is also contemplated that the angle of inclination may not be uniform along the entire length of the angled outlet face and may vary. In embodiments where the bevel angle varies along the bevel exit face, it will be appreciated that the bevel angle should be an average along the entire length of the bevel portion.

The inclined outlet face may have an inclined length that is a length of the inner tube from a starting point where the inclination starts to a terminating point at an exposed end of the inner tube where the inclination terminates.

The length of the inclination may be in the range from 1.0mm to 4.0 mm. More preferably, the inclined length may be in the range from 1.5mm to 3.5 mm. Most preferably, the inclined length may be in the range from 2.0mm to 3.0 mm.

The angled outlet face may include an angled slot. The inclined groove may include: a rim portion disposed between the inner tube and the outer tube and formed by the inner tube; and a central portion formed by the slot itself.

The inclined groove may have a groove width defined by a distance between the edge portions. The slot width may be in the range from 0.90mm to 1.50 mm. More preferably, the width of the groove may be in the range from 1.05mm to 1.30 mm. Most preferably, the width of the groove may be in the range from 1.10mm to 1.20 mm.

The angled slot may have a slot angle defined by the angle at which the slot is angled from the beginning of the slot toward the exposed end of the inner tube. The slot angle may be in the range from 35.0 ° to 10.0 °. More preferably, the angle may be in the range from 28.0 ° to 17.0 °. Most preferably, the angle may be in the range from 23.0 ° to 20.0 °.

It will be appreciated that the angled slot (when present) has a greater angle of sloping than the angled exit face described herein.

The inclined groove may have a groove length that is a length of the inner tube from a starting point at which the groove starts to a terminating point at an exposed end of the inner tube at which the groove terminates. The slot length may be in the range from 1.0mm to 3.5 mm. More preferably, the slot length may be in the range from 1.3mm to 2.8 mm. Most preferably, the slot length may be in the range from 1.5mm to 2.0 mm.

The configuration of the inclined grooves (when present) provides the further advantage of reducing the gap between the air outlet and the water outlet at the exposed end of the inner tube. In this way, it was found that the quality of the atomized water spray can be further improved.

It is envisaged that the gap at the exposed end of the inner tube between the bottom of the inclined trough and the centre of the water outlet may be in the range 0.6mm to 0.4 mm.

The use of an inclined outlet face at the end of the inner tube enables the air and water streams to be brought closer together as they exit the nozzle tip. It is therefore believed that this reduction in the distance between the air flow and the water flow will result in better spray quality and spray atomization.

The distance between the air flow and the water flow may be defined and measured as the distance between the bottom edge of the inclined outlet face (or inclined groove, when present) and the closest peripheral edge point of the water outlet at the exposed end of the inner tube.

For an inner tube with an inclined outlet face, the distance between the air flow and the water flow may be in the range from 0.80mm to 0.50 mm. More preferably, the distance may be in the range from 0.78mm to 0.58 mm. More preferably, the distance may be in the range from 0.72mm to 0.64 mm.

It will be appreciated that in an inner tube embodiment that also includes an angled slot feature, the distance may be further reduced. For embodiments with inclined grooves, the distance between the air flow and the water flow may be in the range from 0.08mm to 0.22 mm. More preferably, the distance may be in the range from 0.11mm to 0.19 mm. Most preferably, the distance may be in the range from 0.13mm to 0.17 mm.

A releasable attachment device may be arranged between the injector device and the nozzle tip. Any suitable releasable attachment means may be used.

In one embodiment, the nozzle tip may have a cap member that may be fixed to or integral with the outer tube, and the cap member may have attachment means formed thereon. The attachment means may comprise a screw thread provided inside the cap part, or may comprise bayonet or detent receiving means.

The dental device may further comprise an adapter arranged between the nozzle tip and the syringe device, the adapter allowing the nozzle tip to be attached to the device. Thus, when an adapter is present, the same nozzle tip can be fitted to different syringe devices by using different adapters, which may have a cap part with a threaded attachment provided inside it and threads for engagement with the nozzle tip, or with a bayonet or detent for reception in a bayonet or detent receiving means on the nozzle tip.

The adapter may be arranged to cooperate with the nozzle tip by means of a fixing means which provides a leak-proof connection between the nozzle tip and the adapter. Preferably, the adapter has a recess therein in which one end of the fixing means is located. In this way, a seal may be provided to secure and seal the end of the fixture in the recess. The seal may be an "O" ring or rubber seal or the like.

A sealing device may be arranged between the inner tube and the outer tube. The sealing means may comprise a moulded seal formed around the outer surface of the enlarged end portion of the inner tube and in contact with the inner surface of the outer tube.

The molded seal may be formed by a raised rim (bead) seal integral with the inner tube. A molded seal may be formed on the inner tube and around the periphery of the enlarged end portion. The rim moulding seal is preferably continuous and uninterrupted.

The molded seal may be positioned between the starting point and the exposed end of the angled exit face (or angled groove, when present). When so positioned, the molded seal will not be continuous around the edge of the angled exit face or angled groove. Thus, the molded seal may be located approximately halfway along the enlarged end portion. Also, the reduced diameter portion of the enlarged end portion is preferably disposed from the outlet face up to the molded seal.

In alternative embodiments, the sealing means may comprise an O-ring, a rubber seal, or the like.

By arranging the sealing means between the outer tube and the inner tube, the sealing means may provide a more gas tight seal between the inner tube and the outer tube.

Without wishing to be bound by theory, it is believed that the use of a tight-fitting inner tube in combination with a slanted outlet face provides improved air velocity and atomized water spray quality. The angled outlet face provides a non-circular air flow that is controlled due to the diverging outlet chamber for the air flow passage. This is transformed from a circular air flow (as shown in the prior tip, also described in patent GB 2213732) into a non-circular air flow, as shown in the certificate of the invention which has been found to be advantageous.

The result of these features can be a change in the velocity of the air jet exiting the nozzle tip and provide better spray patterns and atomization due to the proximity of the water and air streams at the end of the nozzle tip.

All of the features described herein may be combined with any of the above aspects, in any combination.

Drawings

For a more complete understanding of the present invention and to show how embodiments thereof may be carried into effect, reference will now be made by way of example to the following description and accompanying drawings, in which:

FIG. 1 shows a schematic perspective view of a dental apparatus;

FIG. 2 shows a side cross-sectional view of the nozzle tip;

FIG. 3 shows a perspective view of the inner tube;

FIG. 4 shows a partial side view of the inner tube of FIG. 3;

FIG. 5 shows a schematic partial perspective view of the inner tube of FIG. 3;

FIG. 6 shows a schematic end view of a nozzle tip;

FIG. 7 shows a perspective view of an alternative embodiment of an inner tube;

FIG. 8 shows a schematic partial perspective view of the inner tube of FIG. 7;

FIG. 9 shows a partial side view of yet another alternative embodiment of an inner tube; and

fig. 10 shows a partial top view of the inner tube of fig. 9.

Detailed Description

Referring now to fig. 1, a dental device 10 is shown, the dental device 10 including a nozzle tip 11 for a three-way syringe device 12. The injector device 12 comprises a body 13 connected to a flexible coaxial tubular structure 14, which flexible coaxial tubular structure 14 is itself connected to a source of air and water under pressure (not shown). Two levers 15, 16 are arranged on the body 13 and are operable to allow air, water or air and water to flow through the device 10.

The injector device 12 has a head 17 provided with a snap-fit fitting 18. An adapter 9 is also provided, the adapter 9 being according to a complementary snap-fit fitting by means of which the adapter 9 (and attached nozzle tip 11) can be detachably attached to the head 17. The nozzle tip 11 has a bayonet receiving slot on the cap part 19 which is engageable with the complementary bayonet on the adapter 9. Thus, the nozzle tip 11 can be easily attached to and detached from the adapter 9 by the cooperation of the bayonet and the bayonet receiving slot.

The nozzle tip 11 includes an inner tube 20 and an outer tube 21 (both shown in FIG. 2) that form a coaxial tube assembly from the cap member 19 to the air/water injection end 22. The inner and outer tubes 20, 21 are sealingly engaged with mating inner and outer tubes of the adapter 9, which adapter 9 in turn sealingly engages with the head 17 of the syringe device 12. This ensures that one fluid medium does not flow back along the supply line for the other fluid medium (when the other fluid medium is not used).

The inner tube 20 is formed from a plastics material. The outer tube 21 is formed separately from a plastics material and may be moulded integrally with the cap member 19. Then, the nozzle tip 11 is assembled by inserting the inner tube 20 into the outer tube 21. In this way, the nozzle tip 11 can be produced inexpensively so that it can be discarded after the device 10 is used on a patient in order to reduce the risk of cross-infection of any subsequent patient. A new uncontaminated nozzle tip 11 can be easily attached to the head 17 for use of the device 10 with another patient. The nozzle tip 11 may be removed and replaced with the adapter 9, or alternatively, only the nozzle tip 11 may be replaced, leaving the adapter 9 attached to the head 17 for reuse.

Other easily detachable attachment means will be readily apparent to those skilled in the art. For example, the snap-fit fitting and bayonet may be replaced by a threaded or radially outwardly spring-loaded detent received in a hole or outwardly directed recess in the cap member 19, or the internal hole of the cap member 19 may be dimensioned such that the cap member 19 simply push fits over the shoulder of the adaptor 9.

Referring to FIG. 2, a cross-sectional view of the nozzle tip 11 as shown in FIG. 1 is shown. The tip 11 comprises an inner tube 20 and an outer tube 21, both of which are injected with cotton. The two parts 20, 21 combine to provide separate flow channels for water and air. The water flows along a central conduit 27 in the inner tube 20 and the air travels in an annular region 28 between the inner tube 20 and the outer tube 21. The water and air streams exit from the end 22 of the tip 11 to provide a water jet, an air jet, or a combined water/air spray, as selected by the user.

The tip 11 is mounted to a syringe 12 by means of an adapter 9, as shown in fig. 1.

The inner tube 20 also has four flanges 30, the four flanges 30 being disposed toward the cap 19 end of the nozzle tip 11. These flanges 30 are arranged at 90 ° on the outer surface of the inner tube 20 and are in contact with the inner surface of the outer tube 21. A flange 30 extends radially outwardly from the enlarged portion of the inner tube 20. The flange 30 is a clearance fit against the inner surface of the outer tube 21. The flange 30 provides an axial "stop" when the nozzle tip 11 is assembled by inserting the inner tube 20 into the outer tube 21. The end of the flange 30 is pushed against a stop surface at the injector end of the outer tube 21, which ensures correct axial positioning of the inner tube 20 in the outer tube 21 so that the end of the inner tube 20 is flush with the end of the outer tube 21 at the end 22 of the nozzle tip 11.

In addition, the inner tube 20 also has four elongated ribs 29, the four elongated ribs 29 being disposed along a central portion of the nozzle tip 11. The elongated ribs 29 are also disposed at 90 ° on the outer surface of the inner tube 20 and are also in contact with the inner surface of the outer tube 21. Both the flange 30 and the elongated rib 29 enable the inner tube 20 to be correctly centered in the outer tube 21 during manufacture and also continue to hold the inner tube 20 in the correct position during shipping, storage and use.

Referring to fig. 3, a perspective view of the inner tube 20 of fig. 2 is shown. The inner tube 20 is shown having flanges 30, the flanges 30 being disposed at 90 ° to each other and toward one end of the inner tube 20. The inner tube 20 is further provided with elongate ribs 29 which are arranged along the length of the tube 20 and are formed by integral moulding during manufacture of the inner tube 20.

Referring to fig. 4, a partial side view of the inner tube 20 of fig. 2 and 3 is shown. The inner tube 20 includes an end portion 26, the end portion 26 having an angled outlet face 24 disposed on one side thereof. The angled outlet face 24 is an angled portion in which the angle is downward toward the end of the inner tube 20. The remainder of the end portion 26 of the inner tube 20 is dimensioned such that it forms a tight interference fit against the inner surface (not shown in fig. 4) of the outer tube 21.

In this way, the air flow traveling along the area 28 between the inner tube 20 and the outer tube 21 is directed through the angled outlet face 24 and out of the tip 11. The air flow can then be combined with the water jets exiting the inner tube 20 at a separate outlet 25, and this outlet 25 is positioned at the centre of the inner tube 20.

The inner tube 20 also includes a plurality of elongated ribs 29, the elongated ribs 29 being disposed about the outer surface of the tube 20. There are four elongated ribs 29, the four elongated ribs 29 being arranged at 90 ° to each other.

Referring to fig. 5, a partial perspective schematic view of the inner tube 20 of fig. 4 is shown. Fig. 5 shows the same feature of the inner tube 20, the inner tube 20 comprising an inclined outlet face 24 arranged at the end of the tube 20. The air flow will be directed through the angled outlet face 24 and out of the tip 11 from the angled outlet face 24. In addition, a water jet outlet 25 is shown. The water flows along a conduit that is centrally located along the length of the inner tube 20.

As can be seen in fig. 5, the inclined outlet face 24 is provided to cause an air flow to exit the tip 11 which is close to the water flow exiting the outlet 25, which therefore causes good mixing of the water and air jets so as to form a good quality atomized water spray.

Referring to FIG. 6, a schematic end view of the nozzle tip 11 of FIG. 2 is shown. The nozzle tip 11 is formed by an outer tube 21 and an inner tube 20. In addition, the figure shows an inclined outlet face 24 of the inner tube 20, which inclined outlet face 24 can be used to cause the air flow to exit from the tip 11. The angled outlet face 24 provides an exposed end of the inner tube 20 having a cross-section with a partially circular shape. An outlet 25 for the water flow from the tip 11 is also shown at the center of the inner tube 20.

For a non-inclined outlet face, the inner tube 20 is arranged such that it has a tight fit against the outer tube 21. This ensures that the air flow is directed to the angled outlet face 24 without leaking from the tip 11 around the non-angled outlet face.

Referring to fig. 7, a schematic perspective view of an alternative embodiment of the inner tube 40 is shown. Referring to fig. 8, a partial perspective schematic view of the inner tube of fig. 7 is shown. The inner tube 40 of this alternative embodiment can be used with the tip 11, the syringe 12 and the outer tube 21 as shown in fig. 1 to 6.

The inner tube 40 comprises an end portion having an inclined outlet face 43, the inclined outlet face 43 being similar to that shown in figures 3 to 6. However, in this alternative embodiment, the inclined outlet face 43 further comprises an inclined slot 44, which inclined slot 44 has an abutment 45 arranged on either side. The inclined groove 44 has an increased inclination angle compared to the inclined outlet face 43.

An outlet 42 for water flow out of the tip is also shown at the center of the inner tube 40.

The inner tube 40 is also shown having a flange 46 and elongated ribs 41 disposed about the outer surface of the inner tube 40. There are provided four flanges 46 and four elongate ribs 41 arranged around the inner tube 40, which are arranged at 90 ° to each other. These flanges 46 and ribs 41 serve the same function as the flanges and ribs shown in the embodiment of figures 2 to 6.

Referring to fig. 9, a partial side view of yet another alternative inner tube 60 is shown. The inner tube 60 of this alternative embodiment can also be used with the tip 11, the syringe 12 and the outer tube 21 as shown in fig. 1 to 6.

The inner tube 60 includes an end portion 66, the end portion 66 having an angled outlet face 64 disposed on one side thereof. The angled outlet face 64 is an angled portion, as previously described, wherein the angle is angled downward toward the end of the inner tube 60. However, as shown in fig. 10, in this embodiment the inclined outlet face 64 further comprises an inclined slot 63, the inclined slot 63 having abutments 65 arranged on either side. The inclined groove 63 has an increased inclination angle compared to the inclined outlet face 64.

The remainder of the end portion 66 of the inner tube 60 is dimensioned such that it forms a tight interference fit against the inner surface (not shown in fig. 9) of the outer tube 21. However, the end portion 66 includes a molded seal in the form of the circumferential rim 62, the circumferential rim 62 being positioned approximately half way along the end portion 66. The rim 62 is continuous and uninterrupted except for the portion of the angled exit face 64. The rim 62 improves the seal between the end portion 60 and the inner surface of the outer tube 21.

The end portion 66 also provides a reduced diameter portion 67 between the rim 62 and the free end of the end portion 66 to provide a stepped end portion 66. The reduced diameter portion located near the free end of the inner tube 60 makes it easier to assemble the inner tube 60 with the outer tube 21.

As previously described, the air flow travels along the region 28 between the inner tube 60 and the outer tube 21 and is directed through the angled outlet face 64 and out of the tip 11. The air flow can then be combined with the water jets exiting the inner tube 60 at a separate outlet 69, which outlet 65 is located in the center of the inner tube 60.

Although it is seen that fig. 7-8 and 9-10 illustrate alternative inner tubes 40, 60 in which the angled outlet face 43 and enlarged head portion 66 are different from those shown in fig. 3-6, it should be appreciated that other variations are possible.

In order to further understand the present invention, experiments are performed below, and the results are explained in detail.

It should be understood that all tests and physical characteristics listed are determined at atmospheric pressure and room temperature (i.e., 20 ℃) unless otherwise indicated herein or unless otherwise indicated in the context of the relevant test methods and procedures.

Test method

Velocity of air

The air velocity test was conducted with a smaller anemometer to measure the air velocity in meters per second (m/s). The anemometer used was "JD Skywatch Xplorer 2" available on the market. The anemometer is used to determine the maximum speed obtained over a given period of time, as this provides a more consistent result (where the readings may be subject to some degree of variation compared to measuring the instantaneous speed).

The test method included placing a horizontal bar in front of the anemometer to provide a distance marker to ensure that all readings were taken at the same distance from the nozzle tip, which was set at 40mm from the front of the anemometer. All tests were conducted at 40psi air pressure and 40psi water pressure.

The test was performed by continuously injecting air into the anemometer for a time (10-20 seconds) during which the angle of the tip was continuously adjusted to ensure that the air jet hit all areas of the fan. When the test is completed, the anemometer represents the maximum air velocity obtained during the test, and this velocity is recorded in meters per second (m/s).

Spray mist

The assessment of spray performance follows a more empirical approach due to the subjective nature of spray quality and the absence of any readily measurable data. Spray quality can be considered to be determined by two characteristics:

1. spread of the spray-i.e. angle of the resulting conical spray shape;

2. the level of atomization-i.e. the spray should be a fine mist without large water droplets.

Category 5 evaluation criteria have been developed to help identify different types of sprays, which are named as follows: none, poor, good and excellent. For example, a "good" spray should be one that results in a spray that has a good, wide-angle conical shape and is thoroughly and sufficiently atomized. A "poor" spray should be one that has a very narrow spread and contains large visible water droplets, i.e. not be sufficiently atomized. The category "none" indicates no atomization at all and the water jet is seen as being continuously in line.

The spray test was performed against a black background in a well-lit area to provide better visibility of the spray quality.

Test data

A series of tests were conducted to evaluate the air velocity and spray quality performance exiting the tip and the tip of the present invention. The desired spray performance should be that most of the tips tested have a good, good and fair class of spray quality. In addition, it is also desirable that the air velocity exhibited by the tip should be 13.5m/s or more.

Multiple tips were tested according to the method described herein for two commercially available syringes to determine air velocity and the average obtained was used to eliminate minor experimental variations. The results obtained are shown in table 1.

TABLE 1 air velocity values

Syringes a and B are commercially available syringes.

Manufacturer tip-this tip is a standard reusable tip available from the manufacturer of the syringe. The tip includes two separate circular channels, one for air and one for water. At the exposed end of the tip, each channel has a circular outlet.

Standard Pro tips-this is an existing Pro tip device (as shown in GB 2213732) which was invented by the applicant. The nozzle has an inner tube and an outer tube. The inner tube does not form a tight fit against the outer tube and comprises two smaller grooves, each arranged on opposite sides and around the circumference of an end portion of the inner tube.

Tip a-this is the tip of the present invention, has a beveled exit face with a bevel angle of 5.71 ° to 7.97 °, a diameter clearance value of 0.05mm to-0.15 mm, and a height of the exposed end of the inner tube of 2.55mm to 2.65 mm. The tip has an inner tube and an outer tube with a tight interference fit.

Tip B-this is the tip of the present invention, having a beveled exit face with a bevel angle of 4.06 to 5.20 °, a diameter gap value of 0.07 to-0.08 mm, and a height of the exposed end of the inner tube of 2.65 to 2.70 mm. The tip has a tight interference fit and a sloped exit face at the exposed end of the inner tube. Tip B has a reduced bevel angle compared to tip a and a larger radial clearance than tip a.

Tip C-this is the tip of the present invention, having a beveled exit face with a bevel angle of 4.57 ° to 5.48 °, a diameter clearance value of 0.05mm to-0.15 mm, and a height of the exposed end of the inner tube of 2.66mm to 2.70 mm. The tip also included an inclined groove having an angle of 21.9 deg. and a distance of 0.15mm between the water and air jets. The tip has a tight fit between the inner and outer tubes at the end portion.

The tip was further tested according to the methods described herein to determine spray quality. Multiple tips were used in order to eliminate minor experimental variations. The percentage of tip samples that fit into the defined spray quality categories is shown in table 2.

All tips were tested using syringe B at 40psi water pressure and 40psi air pressure.

TABLE 2 spray quality values

The remaining percentage of each tip specimen had a poor or no spray performance classification.

For all three tips of the present invention (i.e., tips A, B and C), the air velocity values at higher and lower pressures and the spray quality are significantly improved over prior tips (e.g., standard Pro tips).

It can be seen that for tip a, the air velocity value is very good, which exceeds the speed of existing Pro tip syringes and manufacturers' syringes. In addition, the spray velocity results for tip a are also significantly improved over the prior Pro tips. Tip a produced superior performance in terms of air velocity and spray, both at lower and higher pressures, on different syringe types.

It can be seen that for tip B, the air velocity value is very good, which exceeds the speed of existing Pro tip syringes and manufacturers' syringes. The spray velocity results were also significantly improved compared to the current Pro tips. Most of the tips of tips B have at least a "still" or better spray quality. Tip B provides a good compromise between spray quality and air velocity and yields excellent performance in terms of air velocity and spray for different syringes and at different pressures.

The tip C additionally comprising inclined grooves again provides air velocity results at different pressures (compared to the existing Pro tip). In addition, the spray quality results shown in table 2 indicate good spray quality, with over 50% of the tips having a good classification of spray quality and also 36% of the tips having good or even good spray quality.

It will be appreciated that the invention is not restricted to details of the above-described embodiments, which have been presented by way of example only. Many variations are possible.

Claims (15)

1. A nozzle tip for a three-way injector device, the nozzle tip comprising a coaxial tube assembly having attachment means for releasably attaching the nozzle tip to an injector device, wherein the coaxial tube assembly comprises an outer tube and an inner tube, the inner tube comprising an exposed end having a water outlet and a hollow conduit extending along the length of the inner tube providing a flow of water from the attachment means to the water outlet, an annular air flow region being provided between the inner and outer tubes, the inner tube having an enlarged end portion at the free end of which the exposed end is, the enlarged end portion comprising an inclined outlet face, and an air flow travelling between the inner and outer tubes along the annular air flow region and being directed through the inclined outlet face of the enlarged end portion so as to flow from the nozzle tip Wherein the inner tube forms a tight interference fit against the inner surface of the outer tube at a location of the enlarged end portion other than the angled outlet face, characterized in that the angled outlet face provides an expanding outlet chamber for the air flow.

2. The nozzle tip of claim 1, wherein: the outer tube and the inner tube are manufactured separately and then assembled, the assembly including inserting the inner tube within the outer tube.

3. The nozzle tip according to claim 1 or 2, wherein: the exposed end of the inner tube is flush with the exposed end of the outer tube.

4. The nozzle tip of claim 3, wherein: the height of the exposed end of the inner tube is a dimension from the angled outlet face to a most peripheral point of the inner tube, the height being in a range from 2.00mm to 3.20 mm.

5. The nozzle tip according to claim 1 or 2, wherein: the inner diameter of the outer tube is in the range from 3.00mm to 3.50 mm.

6. The nozzle tip of claim 1, wherein: the enlarged end portion of the inner tube has a length in a range from 1mm to 4 mm.

7. The nozzle tip according to claim 1 or 2, wherein: the angled outlet face is formed by an angled cut and is arranged such that the enlarged end portion of the inner tube decreases in size towards the exposed end.

8. The nozzle tip of claim 7, wherein: the angled outlet face has an oblique angle that is an angle of the angled outlet face that is angled from a beginning of the enlarged end portion toward an exposed end of the inner tube and relative to a horizontal axis, the angle being in a range from 3.00 ° to 7.00 °.

9. The nozzle tip of claim 7, wherein: the angled outlet face includes an angled slot, the angled slot including: a rim portion disposed between the inner tube and the outer tube and formed by the inner tube; and a central portion formed by the inclined groove itself.

10. The nozzle tip of claim 9, wherein: the inclined groove has a groove width defined by a distance between the edge portions, the groove width being in a range from 0.90mm to 1.50 mm.

11. The nozzle tip of claim 9, wherein: the inclined groove has a groove angle defined by an angle at which the inclined groove is inclined from a start point thereof toward the exposed end of the inner tube, the groove angle being in a range from 35.0 ° to 10.0 °.

12. The nozzle tip of claim 9, wherein: the angled slot has a slot length, the slot length being a length of the inner tube from a starting point at which the angled slot begins to a terminating point at an exposed end of the inner tube, the angled slot terminating at the exposed end, the slot length being in a range from 1.0mm to 3.5 mm.

13. The nozzle tip of claim 9, wherein: a gap between a bottom of the inclined groove and a center of the water outlet at an exposed end of the inner tube is in a range of 0.6mm to 0.4 mm.

14. The nozzle tip according to claim 1 or 2, wherein: a sealing arrangement is disposed between the inner tube and the outer tube, the sealing arrangement including a molded seal formed around an outer surface of the enlarged end portion of the inner tube and in contact with an inner surface of the outer tube.

15. A dental device comprising a nozzle tip for a three-way syringe device according to any of the preceding claims.