POWDER MIXED GAS GENERATOR

Abstract

A powder-mixed-gas generator (20) includes a chamber (42) for containing powder (47) (the chamber being constituted of a vessel body (23) and a lid (24)), a gas injector (25) located within the chamber (42) for injecting a gas (54), and a mixture-gas discharger (26) for discharging a mixture gas (55) in which the gas and the powder (47) is mixed to the outside. The gas injector (25) injects the gas (54), thereby forming a circulation stream (52) that circulates inside the space (53). The mixture-gas discharger (26) has a mixture-gas suction port (49) for receiving the mixture gas (55). The mixture-gas suction port (49) has an opening that faces a direction in which the circulation stream (52) flows.

Claims

1. A powder-mixed-gas generator capable of supplying a suitable amount of powder from a vessel storing the powder to outside, the vessel including a chamber having a shape resembling a sphere as a whole having a bottom being a hemispherical surface and a ceiling being a curved surface, the powder-mixed-gas generator comprising a gas injector configured to inject a gas into the chamber, and a mixture-gas discharger configured to discharge the suitable amount of the powder together with the gas, a distal part of the gas injector being bent to be parallel with the hemispherical surface and being elongated into the chamber so that the gas injected therefrom is directed to a bottom of the hemispherical surface or neighborhood thereof, a mixture-gas suction port of the mixture-gas discharger being located above the stored powder and located at an intermediate position between the hemispherical surface and the curved surface, the mixture-gas suction port of the mixture-gas discharger being arranged along a wall of the chamber for receiving the powder flowing along the curved surface.

2. The powder-mixed-gas generator according to claim 1, wherein the powder is a tooth-surface-cleaning powder.

3. A powder-mixed-gas generator capable of supplying a suitable amount of powder from a vessel storing the powder to outside, the generator comprising: a chamber having a space for containing the powder; a gas injector located within the chamber and configured to inject gas; and a mixture-gas discharger configured to discharge a mixture gas in which the gas and the powder is mixed to outside, the gas injector injecting the gas, thereby forming a circulation stream that circulates inside the space, the mixture-gas discharger including a mixture-gas suction port for receiving the mixture gas, the mixture-gas suction port having an opening that faces a direction in which the circulation stream flows.

4. The powder-mixed-gas generator according to claim 3, wherein the space comprises a first region in which the circulation stream flows and a second region in which the circulation stream does not flow, the powder and the gas are mixed to form the mixture gas in the first region, the powder that has not been included in the mixture gas is stored in the second region, and when the powder is removed from the first region in response to discharge of the mixture gas, the powder in the second region is automatically supplied to the first region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 is a perspective view of a tooth-surface-cleaning apparatus.

[0040] FIG. 2 is a view for showing the appearance of a powder-mixed-gas generator according to an embodiment of the present invention.

[0041] FIG. 3 is a cross-sectional view of the powder-mixed-gas generator.

[0042] FIG. 4 is a view for explaining the shape of a chamber.

[0043] FIG. 5 is a view for explaining a relationship between a gas injector and a mixture-gas discharger.

[0044] FIG. 6 is a view taken along line 6 in FIG. 3.

[0045] FIG. 7 is a view taken along line 7 in FIG. 3.

[0046] FIG. 8 is a view for explaining an operation of the powder-mixed-gas generator.

[0047] FIG. 9 is a view for explaining the operation of the powder-mixed-gas generator.

MODE FOR CARRYING OUT THE INVENTION

[0048] Hereinafter, with reference to the accompanying drawings, an embodiment of the present invention will be described.

Embodiment

[0049] As shown in FIG. 1, a tooth-surface-cleaning apparatus 10 includes a box-type control unit 13 including a water tank 11 and a powder-mixed-gas generator 20; a first tube 14 extending from the control unit 13; a dental-scaling handpiece 15 connected to the distal end of the first tube 14; a second tube 16 extending from the control unit 13; and a tooth-surface-cleaning handpiece 17 connected to the distal end of the second tube 16.

[0050] Dental calculus is separated from the tooth by ultrasonic vibration of the dental-scaling handpiece 15 with water supply from the water tank 11, and is removed by the water.

[0051] The tooth-surface-cleaning handpiece 17 receives a supply of a mixture gas in which a powder is mixed with a gas from the powder-mixed-gas generator 20, and fulfills a role for injecting the mixture gas onto teeth surfaces.

[0052] The powder-mixed-gas generator 20 is contained in a box-type case 21. A transparent inspection window 22 is fitted to the front surface of the case 21 for confirming the residual quantity of the powder through the inspection window 22.

[0053] Hereinafter, the powder-mixed-gas generator 20 will be described in detail.

[0054] As shown in FIG. 2, the powder-mixed-gas generator 20 includes a vessel body 23 having a bottom that is a hemispherical shell, a lid 24 for closing a top opening of the vessel body 23, a gas injector 25 attached to the vessel body 23, and a mixture-gas discharger 26 attached to the vessel body 23. In other words, the vessel includes the vessel body 23 and the lid 24.

[0055] As shown in FIG. 3, the vessel body 23 includes a hemispherical shell section 29 of which the inner surface is a hemispherical surface 28, a cylindrical section 31 extending upward from the hemispherical shell section 29, a lid-fixing ring 32 mounted on the top of the cylindrical section 31, and a packing 33 fitted to the lid-fixing ring 32 and placed on the top surface of the cylindrical section 31. The hemispherical shell section 29 and the cylindrical section 31 constitute a single continuous unit although the curved line and the straight line are isolated by a line 34.

[0056] The lid 24 includes a lid body 36 of which the lower surface is a curved surface 35, a male thread 37 formed around the lid body 36, and a finger grip section 38 bridging over the lid body 36. By pinching and twisting the finger grip section 38, the male thread 37 is screwed into a female thread 39 provided at the lid-fixing ring 32 and is loosened from the female thread 39.

[0057] As shown in FIG. 4, let us assume that the radius of the hemispherical surface 28 is R1. The lid body 36 is arranged so as to be brought into contact with an imaginary circle 41 described with the radius R1 from outside. As a result, a chamber 42 within the vessel body 23 becomes to have a shape resembling the circle with the radius R1.

[0058] The cylindrical section 31 is essential for mounting the lid-fixing ring 32, but it is preferable that the axial length L thereof be small. In this embodiment, L is 0.8 times R1, but L can be selected from a range in which 0.6(L/R1)0.9. It is not preferable that L be greater than 0.9 times R1 since it will be difficult for the chamber 42 to have a shape resembling a circle. It is not preferable that L be less than 0.6 times R1 since it will be difficult to attach the lid-fixing ring 32.

[0059] The radius R2 of the curved surface 35 of the lid body 36 is decided to be greater than the radius R1. By deciding that R1<R2, the height of the lid 24 can be small, so that the powder-mixed-gas generator 20 can be downsized. However, since the chamber 42 should have a shape resembling a circle, it is recommended that R2 be selected from a range in which 1.1(R2/R1)1.3.

[0060] The gas injector 25 is, for example, a J-shaped tube of which the distal part 44 is arranged in parallel to the hemispherical surface 28 with a uniform distance d between the distal part 44 and the hemispherical surface 28. An injection opening 45 of the gas injector 25 is directed to (substantially the center of) the bottom 46 of the hemispherical surface 28. The distance d is selected from a range in which d is 0.5 to 1.5 times the outer diameter of the distal part 44.

[0061] If the distance d is less than 0.5 times the outer diameter of the distal part 44, there may be a risk that the gap between the hemispherical surface 28 and the distal part 44 is clogged up with powder 47. If the distance d is greater than 1.5 times the outer diameter of the distal part 44, it will be difficult to form a gas flow (denoted by symbol 48 in FIG. 5) along the hemispherical surface 28.

[0062] The powder 47 is, for example, a tooth-surface-cleaning powder made of calcium carbonate or sodium carbonate of which the average particle diameter is 50 to 80 micrometers.

[0063] The mixture-gas discharger 26 is arranged along the wall of the cylindrical section 31, so as to be capable of receiving the powder 47 flowing along the curved surface 35 of the lid body 36.

[0064] More specifically, as shown in FIG. 5, the mixture-gas discharger 26 is arranged, such that a mixture-gas suction port 49 of the mixture-gas discharger 26 overlaps (including substantially overlaps) an operational circle 48 that passes through the distal part 44 of the gas injector 25 and is parallel with the hemispherical surface 28. It is expected that pressurized gas flows along the operational circle 48.

[0065] As shown in FIG. 6, the gas injector 25 is bent for avoiding interference with the mixture-gas discharger 26, but the injection opening 45 of the gas injector 25 is directed to (substantially the center of) the bottom 46 of the hemispherical surface 28.

[0066] As shown in FIG. 7, the mixture-gas discharger 26 is upwardly elongated to an intermediate position between the hemispherical surface 28 (line 34) and the curved surface 35, and the distal end of the mixture-gas discharger 26 is always located above the upper-limit level 51 for the powder 47. This location of the distal end of the mixture-gas discharger 26 ensures that the stored powder 47 is prevented from directly entering the mixture-gas suction port 49.

[0067] The mixture-gas suction port 49 may be provided by cutting the tube obliquely to the axis of the tube, but is provided by cutting the tube perpendicularly with respect to the axis of the tube in this embodiment. In comparison with oblique cutting, this significantly facilitates the cutting process and can reduce the process cost.

[0068] Next, operation of the powder-mixed-gas generator 20 with the above-described structure will be described.

[0069] As shown in FIG. 8, the powder-mixed-gas generator 20 includes the chamber 42 having a space 53 for containing the powder 47 (the chamber 42 having the vessel body 23 and the lid 24), the gas injector 25 located within the chamber 42 for injecting gas 54, and the mixture-gas discharger 26 for discharging a mixture gas 55 in which the gas 54 and the powder 47 is mixed to the outside.

[0070] Here, the gas injector 25 injects the gas 54, thereby forming a circulation stream 52 that circulates inside the space 53. The mixture-gas discharger 26 is located in the path along which the circulation stream 52 flows.

[0071] In this structure, the gas injector 25 injects the gas 54 so that the circulation stream 52 flows along a vertical plane (a plane that is substantially perpendicular to a horizontal plane) passing the inside of the space 53.

[0072] In the above-mentioned powder-mixed-gas generator 20, the space 53 is considered to have a first region 56 in which the circulation stream 52 flows and second regions 57 in which the circulation stream 52 does not flow. In the first region 56, the powder 47 is in contact with the circulation stream 52, so that the powder 47 and the gas 54 are mixed to form the mixture gas 55.

[0073] In the second regions 57, the powder 47 that has not been included in the mixture gas 55 is stored. When the powder 47 is removed from the first region 56 in response to discharge of the mixture gas 55, the remaining powder 47 becomes to have a shape as shown in FIG. 9, and the powder 47 in the second regions 57 is automatically supplied to the first region 56.

[0074] More specifically, in the second regions 57, the powder 47 is stored to have planes 58 oblique to the above-mentioned vertical plane. When the powder 47 is removed from the first region 56 in response to discharge of the mixture gas 55, the powder 47 in the second regions 57 moves from the second regions 57 to the first region 56 along the planes 58 that incline with respect to the vertical plane.

[0075] As shown in FIG. 8, the above-mentioned chamber 42 includes the hemispherical surface 28 and the curved surface 35 that assist the flow of the circulation stream 52 circulating in the space 53. In this structure, the first region 56 utilizes the circulation stream 52 to return the mixture gas 55 to the gas injector 25 along the hemispherical surface 28 and the curved surface 35.

[0076] The above-mentioned gas injector 25 includes the injection opening 45 located near the side part of the hemispherical surface 28. The injection opening 45 injects the gas 54 toward the powder 47 contained in the space 53 of the chamber 42. Accordingly, in the first region 56, the gas 54 injected toward the powder 47 and the powder 47 are mixed to form the mixture gas 55. The mixture gas 55 circulates riding the circulation stream 52, and part of it is discharged. The mixture gas 55 that is not discharged is returned to the gas injector 25 along the hemispherical surface 28 and the curved surface 35 by means of the circulation stream 52.

[0077] The above-mentioned mixture-gas discharger 26 includes a mixture-gas suction port 49 for receiving the mixture gas 55. The mixture-gas suction port 49 includes an opening that faces the direction in which the circulation stream 52 flows (see also FIG. 5).

[0078] In the above-mentioned powder-mixed-gas generator 20, the powder 47 is stored in the space 53 as shown in FIG. 8 in the initial state before the gas 54 is injected from the gas injector 25. In other words, in the initial state, the powder 47 is contained substantially uniformly in the whole region corresponding to each of the first region 56 and the second regions 57.

[0079] Thereafter, in response to the start of injection of the gas 54 from the gas injector 25, part of the powder 47 in the first region 56 is mixed with the gas 54. At this time, the remaining powder 47 in the first region 56 is fed to the second regions 57.

[0080] Although the powder-mixed-gas generator 20 of this embodiment is preferable for the tooth-surface-cleaning apparatus 10, it can be used in a task of cleaning things other than teeth, for example, elements of a precision machine.

[0081] In addition, the structure of the present invention may be applied to a generating apparatus for generating a powder-mixed-gas for transferring powder in, for example, a plant for transferring powder.

DESCRIPTION OF REFERENCE SYMBOLS

[0082] 10: Tooth-Surface-Cleaning Apparatus

[0083] 11: Water Tank

[0084] 13: Control Unit

[0085] 14: First Tube

[0086] 15: Dental-Scaling Handpiece

[0087] 16: Second Tube

[0088] 17: Tooth-Surface-Cleaning Handpiece

[0089] 20: Powder-Mixed-Gas Generator

[0090] 21: Case

[0091] 22: Inspection Window

[0092] 23: Vessel Body of Vessel

[0093] 24: Lid of Vessel

[0094] 25: Gas Injector

[0095] 26: Mixture-gas Discharger

[0096] 28: Hemispherical Surface

[0097] 29: Hemispherical Shell Section

[0098] 31: Cylindrical Section

[0099] 32: Lid-Fixing Ring

[0100] 33: Packing

[0101] 34: Line

[0102] 35: Curved Surface

[0103] 36: Lid Body

[0104] 37: Male Thread

[0105] 38: Finger Grip Section

[0106] 39: Female Thread

[0107] 41: Imaginary Circle

[0108] 42: Chamber

[0109] 44: Distal Part of Gas Injector

[0110] 45: Injection Opening

[0111] 46: Bottom of Hemispherical Surface

[0112] 47: Powder

[0113] 48: Operational Circle

[0114] 49: Mixture-gas Suction Port

[0115] 51: Upper-Limit Level for Stored Powder (Initial State)

[0116] 53: Space

[0117] 54: Gas

[0118] 55: Mixture Gas

[0119] 56: First Region

[0120] 57: Second Region

[0121] 58: Oblique Plane