JP2012236147A - Bubble generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure without requiring a high-speed water current, in a bubble generator including a jet nozzle jetting a jet water current including bubbles into a bathtub.SOLUTION: An orifice 23 for jetting a jet water current provided at a downstream end of a jet nozzle 20 comprises a first orifice 23a at an upstream side and a second orifice 23b at a downstream side having a sectional area larger than that of the first orifice 23a. The second orifice 23b including a level difference part 29 having an expanded cross-section area at least a part in a circumferential direction is continuously provided at downstream end of the first orifice 23a. A negative pressure generated at a back surface of the level difference part 29 is used to suck the bubbles into the water current passing through the orifice 23 at a relatively low speed.

Description

  The present invention relates to a bubble generating device that is provided in a bathtub and generates bubbles in bathtub water in the bathtub.

  As conventional bubble generating devices, for example, those described in Patent Documents 1 and 2 below are known.

JP 2001-347145 A Japanese Patent No. 3084837

  Patent Documents 1 and 2 disclose the structure of a conventional ejector-type bubble generator. This conventional ejector-type bubble generating device includes an ejection nozzle (nozzle portion) that ejects bath water circulated and supplied by a pump at high speed. This jet nozzle is open to the mixing chamber into which the outside air is introduced, and the outside air is naturally aspirated using the negative pressure generated by the cavitation action caused by the high-speed water flow jetted from the jet nozzle. Inhale air. A mixing nozzle (diffuser section) is concentrically disposed on the downstream side of the ejection nozzle, and is configured to eject into the water tank while mixing and dissolving air and water in the mixing nozzle.

  The air in the high-speed jet flow jetted from the mixing nozzles of Patent Documents 1 and 2 is sheared by the speed difference between the jet flow velocity at the nozzle outlet and the water staying in the surrounding area, and is fine. Although it becomes a microbubble, since the bubble density is relatively high, the bubble often recombines. Further, as a condition for generating microbubbles, it is required to increase the water flow rate so that a high shearing force can be obtained, and thus a high-pressure pump is generally required. Furthermore, in order to generate a negative pressure in the mixing chamber, it is necessary to reduce the nozzle inner diameter of the ejection nozzle, which restricts the amount of water flow and must reduce the amount of intake air according to the amount of water flow. The generation efficiency of microbubbles was poor.

  Therefore, an object of the present invention is to provide a bubble generating device that does not require a high-pressure pump and can generate a sufficient amount of bubbles while increasing the amount of water flow.

  In order to achieve the above object, the present invention takes the following technical means.

  That is, the present invention relates to a jet water flow including bubbles from a jet nozzle provided with a bath water inlet to which bathtub water in the bathtub is supplied and an orifice provided downstream of the bathtub water inlet and from which the jet water flow is jetted. In the bubble generating apparatus for jetting the gas into the bathtub, the orifice includes an upstream first orifice part, a second orifice part provided downstream of the first orifice part and having a larger cross-sectional area than the first orifice part. And the second orifice part is continuously provided at the downstream end of the first orifice part with a step part that expands the cross-sectional area at least partially in the circumferential direction, and is used to introduce air into the orifice. A hole is formed in the negative pressure region generated on the back side of the stepped portion, and air is sucked by the negative pressure generated on the backside of the stepped portion. 1).

  According to this, unlike a conventional ejector-type bubble generating device, it becomes possible to suck air through the intake hole by the negative pressure on the back side of the step portion even with a relatively gentle water flow, and the orifice diameter Since there is no need to make the pressure too small, a high-pressure pump is not necessary, and the amount of water flow can be increased, so that even if the amount of intake air is increased, fine bubbles can be stably generated.

  Further, the air intake hole can be formed so as to straddle the stepped portion (claim 2). According to this, the negative pressure decreases as the distance from the stepped portion decreases toward the downstream side, and the negative pressure immediately after the stepped portion is the largest. Therefore, the large negative pressure is applied to the intake holes to efficiently suck air. It becomes possible.

  Further, the stepped portion can be formed over the entire circumference of the orifice, and an air layer generated in the negative pressure region on the back side of the stepped portion during operation can be formed over the entire circumference of the orifice. According to this, bubbles are supplied from the air layer formed in an annular shape on the back side of the stepped portion during operation, and the bubbles are uniformly distributed over the entire circumference of the orifice. Even when the bubbles are generated, the bubbles are not easily bonded to each other, and stable bubbles can be sent downstream.

  Further, the back surface of the stepped portion can be formed in an acute angle in a sectional view with respect to the inner peripheral surface of the orifice. According to this, it is possible to secure a larger space in which an annular air layer is formed, and it is possible to more stably generate bubbles from the entire circumference of the orifice, and to prevent negative pressure on the back side of the stepped portion. Pressure is generated more stably.

  Furthermore, the bubble generating device of the present invention includes a flow passage that connects the bathtub water introduction port and the orifice, and the first orifice portion can be connected to the downstream end of the flow passage via a step portion. In this case, it is preferable that the cross-sectional area of the downstream end of the flow passage is at least twice the cross-sectional area of the first orifice part. According to this, a negative pressure due to the turbulent flow is generated near the inner surface of the first orifice portion due to a sudden decrease in cross section due to the step portion at the downstream end of the flow passage. In combination with the negative pressure generated on the back side of the stepped portion at the boundary, it becomes possible to suck air more efficiently.

  As described above, according to the bubble generating device according to the first aspect of the present invention, unlike the conventional ejector-type bubble generating device, even with a relatively gentle water flow, due to the negative pressure on the back side of the stepped portion. Air can be sucked in through the intake holes, eliminating the need for excessively small orifice diameters, eliminating the need for a high-pressure pump and increasing the amount of water flow. Air bubbles can be generated stably.

  Further, according to the bubble generating device according to claim 2 of the present invention, the negative pressure decreases as the distance from the stepped portion decreases toward the downstream side, and the negative pressure immediately after the stepped portion is the largest. The air can be efficiently sucked by acting on the intake hole.

  Further, according to the bubble generating device of the third aspect of the present invention, bubbles are supplied from an air layer formed in an annular shape on the back side of the stepped portion during operation, and are uniformly distributed over the entire circumference of the orifice. The bubbles are dispersed, and even when a relatively large number of bubbles are generated, the bubbles are not easily combined with each other, and stable bubbles can be sent downstream.

  Further, according to the bubble generating device of claim 4 of the present invention, a larger space in which an annular air layer is formed can be secured, and bubbles can be more stably generated from the entire circumference of the orifice. And the negative pressure on the back side of the stepped portion can be generated more stably.

  According to the bubble generating device of the fifth aspect of the present invention, the negative pressure due to the turbulent flow due to the sudden decrease in the cross section due to the stepped portion at the downstream end of the flow passage is provided near the inner surface of the first orifice portion. Owing to the negative pressure generated on the back side of the step portion at the boundary between the first and second orifice portions, air can be sucked more efficiently.

It is a longitudinal cross-sectional view of the circulation adapter for bathtubs which incorporates the bubble generator which concerns on one Embodiment of this invention. It is a horizontal sectional view of the circulation adapter for the bathtub. It is a perspective view of the circulation adapter for the bathtub. It is a disassembled perspective view of the circulation adapter for bathtubs. It is a bubble generation | occurrence | production principle explanatory drawing of the bubble generation apparatus of the circulation adapter for bathtubs. It is a side view of the ejection nozzle shown in FIG. It is a principal part enlarged view of the experimental model of a bubble generator. It is a principal part enlarged view of the theoretical model of a bubble generator. It is the elements on larger scale which typically show the other Example of a level | step-difference part. It is explanatory drawing of the negative pressure generation principle by a cross-sectional rapid reduction structure. It is a longitudinal cross-sectional view which shows the other Example of an ejection nozzle typically. It is operation | movement explanatory drawing of a collision wall and a scattering prevention wall. It is operation | movement explanatory drawing of a collision wall and a scattering prevention wall. It is a longitudinal cross-sectional view which shows typically another Example of a bubble generator.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  1 to 4 show a circulation adapter 1 for a bathtub in which a bubble generating device according to an embodiment of the present invention is incorporated, and the circulation adapter 1 is attached and fixed in a state of penetrating the side wall of the bathtub. The outer periphery of the front surface (right side surface in the figure) of the adapter 1 is provided with a suction port 2 for sucking in the bathtub water in the bathtub, and a water flow is discharged radially inward of the suction port 2. The water flow discharge port 3 is provided, and the bathtub water sucked from the suction port 2 is connected via the circulation pipe and the circulation adapter 1 by being connected to the circulation pipe provided with the circulation pump on the back side of the circulation adapter 1. It is comprised so that it may discharge | release toward the inside of a bathtub from the water flow discharge port 3. FIG.

  Preferably, the circulation line can be constituted by a reheating circulation line for a bath pot or a bath water heater having a reheating function for a bath, in which case combustion in the bath pot or a water heater is stopped. The bubble generation operation can be performed by causing the circulation of the bath water by the circulation pump.

  The circulation adapter 1 is configured by assembling an adapter main body 4 that also serves as a main body housing disposed mainly outside the bathtub, a bathtub attachment 5 that is attached to the adapter main body 4 from the inside of the bathtub, and a suction port filter 6. In addition, the side wall of the bathtub is sandwiched between the flange 7 of the adapter main body 4 and the flange 8 of the bathtub attachment 5 via the packings 9 and 10, and is fixed to the bathtub. The adapter body 4 is provided with a female screw portion 11, while the bathtub attachment 5 is provided with a male screw portion 12 corresponding to the female screw portion 11, and the bathtub attachment 5 is formed by these screw portions 11 and 12. The adapter body 4 is screwed. The suction port filter 6 is detachably attached to the bathtub attachment 5.

  The adapter body 4 is provided with a return connection port 13 connected to the return path of the circulation pipe and an outgoing connection port 14 connected to the return path of the circulation pipe so as to protrude rearward from the back surface. At the same time, an air intake port 15 is also provided on the back surface so as to protrude rearward. The adapter body 4 includes a first tube portion 16 communicating with the forward connection port 14, a second tube portion 17 provided concentrically with a gap between the first tube portion 16, It is configured in a multiple cylinder shape integrally including a third cylinder portion 18 provided concentrically with a gap between the second cylinder portion 17 and the third cylinder portion 18 of the adapter body 4. An outer peripheral wall is formed, the second cylinder part 17 is accommodated in the third cylinder part 18, and the first cylinder part 16 is accommodated in the second cylinder part 17. The space between the first tube portion 16 and the second tube portion 17 is communicated with the air intake port 15, and the space between the second tube portion 17 and the third tube portion 18 is communicated with the return connection port 13. The internal space of the first tube portion 16, the space between the first tube portion 16 and the second tube portion 17, and the space between the second tube portion 17 and the third tube portion are mutually blocked. Has been. The female thread portion 11 is formed on the inner peripheral surface of the third cylindrical portion 18.

  The bathtub attachment 5 is mainly composed of a cylindrical bathtub bolt 19, an ejection nozzle 20 fitted in the bathtub bolt 19, and a discharge water flow control member 21 having a water flow discharge port 3. The bathtub bolt 19 is provided with the flange 8, the packing 10 is attached to the flange 8, and the male screw portion 12 is formed on the outer peripheral surface of the bathtub bolt 19. In addition, a gap is formed between the inner peripheral surface of the bathtub bolt 19 and the second tube portion 17 of the adapter main body 4, and the return connection port 13 of the adapter main body 4 and the above suction through the gap. The mouth 2 is in communication.

  The jet nozzle 20 jets a jet of water containing bubbles into the bathtub, and a bathtub water inlet 22 through which the bathtub water is supplied via the forward connection port 14 of the adapter body 4, and the bathtub water inlet An orifice 23 provided downstream of the nozzle 22 through which the jet water flow is jetted outward, a flow passage 24 for communicating the bathtub water inlet 22 and the orifice 23, and the air inlet 15 of the adapter body 4. An intake hole 25 for introducing air into the inside is provided. The jet nozzle 20 of the illustrated embodiment is mainly composed of an inner cylinder part 26 having an orifice 23 at a tip part and an outer cylinder part 27 integrally formed concentrically with a gap between the inner cylinder part 26. The rear end portion of the inner cylinder portion 26 is the bathtub water introduction port 22, and the inner space of the inner cylinder portion 26 is the flow passage 24. The upstream end of the orifice 23 is connected to the downstream end of the flow passage 24 via a step portion 28 that forms a rapidly reducing section.

  The inner cylinder part 26 of the ejection nozzle 20 is fitted into the first cylinder part 16 of the adapter body 4, whereby the orifice 23 is communicated downstream of the outgoing connection port 14. On the other hand, the outer cylinder part 27 is fitted into the second cylinder part 17 of the adapter body 4 and a gap is formed between the inner peripheral surface of the outer cylinder part 27 and the outer peripheral surface of the first cylinder part 16. Thus, the outside air is supplied to the space between the inner cylinder part 26 and the first cylinder part 16 and the outer cylinder part 27 via the air intake port 15. The leading end of the space extends to the outside in the radial direction of the orifice 23, and the intake hole 25 that connects the leading end of the space and the orifice 23 is formed in the inner cylinder portion 26.

  The intake hole 25 is constituted by small holes, and in the illustrated embodiment, is constituted by three small holes arranged adjacent to each other in the circumferential direction. In addition, since the small hole which comprises the intake hole 25 is formed in the inner cylinder part 26 by the pin at the time of injection molding, a small hole will also be formed in the outer cylinder part 27, but the small hole of this outer cylinder part 27 is formed. Is sealed by an O-ring 40 provided between the ejection nozzle 20 and the discharge water flow control member 21.

  The orifice 23 of the ejection nozzle 20 is connected to the upstream side first orifice part 23a and the downstream end of the first orifice part 23a with a step part 29 that slightly and rapidly expands the cross-sectional area. The second orifice portion 23b. The second orifice portion 23b is provided on the downstream side of the first orifice portion 23a, and is configured such that the cross-sectional area is suddenly larger than that of the first orifice portion 23a via the stepped portion 29. , 23b is configured to generate a negative pressure in a minute region on the back side (right side in the figure) of the stepped portion 29 when water is passed through the ejection nozzle 22. The intake hole 25 is formed in the stepped portion 29. In particular, in the present embodiment, the intake hole 25 is formed so as to straddle the stepped portion 29, and the negative hole generated on the back side of the stepped portion 29 is formed. It is configured so that air is naturally aspirated by pressure. In the present embodiment, the stepped portion 29 is formed over the entire circumference of the inner peripheral surface of the orifice 23, and is generated in a minute negative pressure region on the back side of the stepped portion 29 during operation (when water flows into the ejection nozzle 20). An air layer is formed over the entire circumference of the orifice 23.

  The principle of bubble generation in a conventional general ejector-type bubble generator is based on the cavitation principle that occurs when a high-speed water flow passes through the orifice and jets the high-speed water flow in a space sufficiently wider than the orifice. In this embodiment, a high-pressure pump is indispensable in order to generate a high-speed water flow. The high-pressure water flow that causes cavitation is not necessary, and low-pressure pumps that are low in cost can be used as circulation pumps to reduce costs and greatly reduce noise. Can be reduced at the same time and the orifice diameter can be made relatively large. Can be secured, even by increasing the amount of air bubbles mixed in the water stream due to this, hardly binds bubbles together, it is possible to generate a good bubble-containing water quality at a rate sufficient.

  FIG.5 and FIG.6 is a bubble generation principle explanatory drawing of a bubble generation apparatus provided with the ejection nozzle 20 of this embodiment shown in FIGS. 1-4. As shown in FIG. 5, when bath water is passed through the ejection nozzle 20 at a predetermined flow rate, the flow velocity is accelerated in the first orifice portion 23a, and the pressure of the water flow passing through the first orifice portion 23a is reduced accordingly. For example, the cross-sectional area of the first orifice portion 23a, the first orifice portion 23a, so that the pressure of the water flow passing through the first orifice portion 23a, particularly the pressure in the vicinity of the inner peripheral surface of the first orifice portion 23a, is substantially equal to the external pressure. The flow path shape and cross-sectional area on the upstream side, the flow rate of bathtub water, and the like can be set. When the water flow passes through the stepped portion 29, a negative pressure is generated in a minute region on the back side of the stepped portion 29, and air is sucked through the intake hole 25 by the negative pressure, and as shown in FIG. An air layer is formed on the back side of the stepped portion 29, and bubbles are generated and mixed uniformly and continuously over the entire circumference in the water flow flowing through the orifice 23 using the air layer as an air supply source. A water flow is ejected outward from the second orifice portion 23b.

  In order to experimentally verify the preferred position of the air intake hole 25, the inventors of the present application confirmed the bubble generation state using a plurality of samples in which the position of the air intake hole 25 was slightly shifted in the axial direction. Such an experimental model is shown in FIG. 7. The lower limit flow rate Q is 4.0 L / min, the diameter φA of the first orifice portion 23a is 4.5 mm, the diameter φB of the second orifice portion 23b is 5.1 mm, and the intake hole The diameter φR of 25 was 1.0 mm. In this case, assuming that the distance between the portion of the intake hole 25 farthest from the stepped portion 29 and the stepped portion 29 is L, bubbles are hardly generated when the distance L exceeds 1.0 mm, and the intake hole 25 It was confirmed that the better the bubbles were generated, the closer the center to the stepped portion 29.

  From this result, as shown in FIG. 8, a relationship of b = 0.3a is derived between the axial dimension b of the negative pressure region on the back side of the step part 29 and the radial dimension a of the step part. Is done. Since it is possible to inhale if L ≦ b, it is understood that stable intake can be performed if the position of the intake hole 25 is set so as to satisfy the condition of L ≦ 0.3a.

  The back surface of the stepped portion 29 of the present embodiment shown in FIGS. 1 to 4 is formed substantially perpendicular to the inner peripheral surface of the orifice 23 in the axial sectional view, but as shown in FIG. The back surface of 29 can also be formed in an acute angle with respect to the inner peripheral surface of the orifice 23 in an axial sectional view. According to this, since the depth of the step portion 29 becomes deeper, the generation of negative pressure is further stabilized, and the layer thickness of the air layer on the back surface of the step portion 29 can be increased. An annular air layer (indicated by dot hatching in FIG. 9) is formed, and the generation of bubbles is made more uniform.

  Further, in this embodiment, as shown in FIGS. 1 and 2, the boundary between the flow passage 24 and the orifice 23 of the ejection nozzle 20 has a cross-sectional sudden reduction structure by the step portion 28. explain. As shown in FIG. 5, when the downstream end of the flow passage 24 is tapered and connected to the orifice 23, turbulent flow is less likely to occur in the pipeline, and the pressure loss is small, and the water flow flowing through the first orifice portion 23a is small. The flow direction is relatively along the axial direction, and the water flow itself does not cause a negative pressure on the inner surface of the orifice 23. On the other hand, as shown in FIG. 10, when the cross section is suddenly reduced at the inlet of the orifice 23, the water flow near the inlet of the orifice 23 is directed radially inward as it goes downstream due to the characteristics of the pipe flow. The water flow that flows through the first orifice portion 23a flows smaller than the diameter of the first orifice portion 23a, thereby generating a negative pressure due to the turbulent flow between the pipe wall and the water flow. By constructing the above-mentioned rapidly expanding section by the step portion 29 in the orifice in the region affected by the negative pressure, a large negative pressure can be generated on the inner surface of the orifice by a synergistic effect. The relative distance between the step portions 28 and 29 for causing such an action is about 2 mm in the present embodiment, although it depends on various conditions such as the tube diameter and the flow velocity.

  As shown in FIG. 11, the structure in which the cross section is rapidly reduced may be a structure in which the upstream end of the orifice 23 protrudes into the upstream flow passage 24.

  Next, the discharge water flow control member 21 will be described. As shown in FIGS. 1 and 2, the discharge water flow control member 21 includes an annular mounting base portion 30 that is externally fitted to the ejection nozzle 20, and the base portion. The collision wall support part 31 integrally formed in 30, the collision wall 32 attached to and supported by the support part 31, and the cylindrical scattering prevention wall 33 covering the outer periphery of the collision wall 32 are mainly configured. An opening around the collision wall 32 serves as the water flow discharge port 3, and the collision wall support portion 31 is arranged in a radial direction from the shaft core portion so as to ensure a sufficient opening amount and smoothly discharge the water flow. It is comprised in the shape of three narrow ribs that extend. The base portion 30 is fixedly attached to the bathtub bolt 19 with a mounting screw (not shown) using a screw hole 19a provided on the front surface of the bathtub bolt 19. The suction port 2 is formed by a gap between the base portion 30 and the bathtub bolt 19.

  The collision wall 32 is a disk-shaped member disposed in front of the ejection nozzle 20 and has a circular collision surface 32a concentrically opposed to the orifice 23 of the ejection nozzle 20 at a predetermined distance. . The collision surface 32 a may be inclined with respect to the axis of the orifice 23, but is preferably disposed perpendicular to the axis of the orifice 23. The diameter of the collision surface 32a is larger than the diameter of the second orifice part 23b, and the distance between the tip of the ejection nozzle 20 and the collision surface 32a is set smaller than the diameter of the second orifice part 23b. Further, the outer diameter of the collision wall 32 is about twice the inner diameter of the second orifice portion 23b.

  In the illustrated embodiment, a support shaft 36 protruding from the side surface opposite to the collision surface 32 a is formed integrally with the collision wall 32, and the support shaft 36 is supported by the collision wall support portion 31. With the structure in which the support shaft 36 is screwed into the support portion 31, the distance between the collision wall 32 and the ejection nozzle 20 can be finely adjusted by rotating the support shaft 36, and the bubble generation state can be adjusted. If the support shaft 36 is supported by the collision wall support 31 so as to be capable of reciprocating in the axial direction, the collision wall 32 is vibrated slightly in the axial direction due to pressure fluctuations during water flow, and is discharged from the water flow outlet 3. Variations can be added to water currents and bubbles.

  At the periphery of the collision surface 32 a of the collision wall 32, the water jet from the jet nozzle 20 flows in the direction of the jet from the jet nozzle 20 through the water flow outlet 3 around the collision wall 32 in the bath water. A guiding curved surface 32b for guiding is formed. This utilizes the property that water flows in water as if it is pulled along the surface of the object.

  The operation of the collision wall 32 having the guide curved surface 32b will be described with reference to FIGS. The lower half of FIG. 12 schematically shows the flow of the jet water flow in water, and the upper half of FIG. 12 schematically shows the flow of the jet water flow in the air. As shown in FIGS. 5 and 12, the jet water flow from the jet nozzle 20 collides with substantially the center of the collision surface 32 a of the collision wall 32, and bubbles in the water flow are first refined by this impact force. After the water flow collides with the collision wall 32, it becomes a flow that is dispersed in the radial direction along the collision surface 32a. However, in the water, the water flow is dispersed toward the outer side in the radial direction, as shown in FIG. As the water film of the water flow becomes thin and a large shearing force acts on the bubbles contained in the water flow as it reaches the peripheral portion of the collision surface 32a, the bubbles are further miniaturized, and a large number of microbubbles having a size of about 20 μm. Occurs. When the water flow reaches the peripheral edge of the collision wall 32, the water flow is bent along the guide curved surface 32b and flows along the ejection direction of the ejection nozzle 20.

  On the other hand, when water is not filled in the bathtub, when a jet water flow is jetted from the jet nozzle 20 in the air by hot water filling operation, since there is no bathtub water that becomes resistance, the water flow collides with the collision surface 32a. If there are no measures to prevent scattering, there is a risk of splashing water from the bathtub. In the present embodiment, the scattering prevention wall 33 is disposed so as to cover the outer periphery of the collision wall 32, and the upper part of the collision wall 32 is covered by the scattering prevention wall 33, so Even when a water flow is jetted, it is possible to prevent a large amount of water splashing from the bathtub.

  The scattering prevention wall 33 is disposed at a position spaced apart from the collision wall 32 by a predetermined distance so as not to hinder the flow of water along the outer peripheral surface of the collision wall 32 during the bubble generation operation in water. Further, preferably, as shown in FIGS. 5 and 12, the tip of the collision wall 32 (the right end in the figure) is more distal than the tip of the scattering prevention wall 33, that is, the water flow from the water flow outlet 3. It can project in the injection direction. According to this, the influence of the turbulent flow due to the presence of the scattering prevention wall 33 can be eliminated from the water flow discharged from the tip of the collision wall 32, and the water flow is more stably directed toward the inside of the bathtub. It can flow evenly and improve the feeling of massage for bathers.

  In addition, a gap 34 is provided between the scattering prevention wall 33 and the ejection nozzle 20 to allow water in the bathtub around the scattering prevention wall 33 to flow toward the collision wall 32 together with the jet water flow ejected from the ejection nozzle 20. Is formed. By the inflow of the bathtub water from the gap 34, the flow of the microbubble water flow discharged forward from the water flow outlet 3 can be made smoother. That is, if the gap 34 does not exist, the surrounding back of the collision wall 32 is blocked by the scattering prevention wall, and the turbulent flow of the bathtub water staying in the closed portion causes a loss in the microbubble water flow, Although there is a concern that the foam quality deteriorates or the water flow rate decreases, in this embodiment, there is a gap 34 that generates a smooth circulatory water around the microbubble water flow along the collision wall 32 surface. Since it is provided, it is possible to generate high-quality bubbles and water flow.

  Further, a protrusion 33a that protrudes radially inward toward the collision wall 32 is provided at the tip of the scattering prevention wall 33 over the entire circumference. It prevents the spilled water from splashing forward. The protrusion 33 a may be integrally formed with the scattering prevention wall 33, or a separately molded member may be attached to the tip of the scattering prevention wall 33. Moreover, the structure of the protrusion part 33a does not need to be folded at right angles from the front-end | tip part of the scattering prevention wall 33, and makes it an appropriate shape according to the momentum which the water repelled by the inner surface of the scattering prevention wall 33 jumps ahead. For example, a structure in which the front end portion of the scattering prevention wall 33 is folded back at an acute angle may be used, or a configuration in which the front end portion of the scattering prevention wall 33 is inclined forward and obliquely may be employed. It should be noted that it is preferable that the distance between the protruding portion 33a and the collision wall 32 is sufficiently large so as not to disturb the water flow.

  As described above, it is not preferable for the scattering prevention wall 33 to protrude too far to the front end side, so that it is not preferable for the generation of a smooth water flow. Therefore, it is preferable to make the scattering prevention wall 33 as short as possible. As a result, the following problems arise. That is, when the water flow is ejected from the ejection nozzle 20 in the air, the water flow has a momentum even after colliding with the collision wall 32 when the ejection flow rate is large. Therefore, as shown by the arrow a in FIG. However, when the flow rate is small or when the flow rate rises and falls before and after the start of ejection, the water flow is pulled by the guide curved surface 32b and splashes obliquely forward as shown by the arrow c in FIG. In some cases, the scattering prevention wall 33 cannot be received.

  Therefore, in the present embodiment shown in FIGS. 1 to 4, the boundary between the collision surface 32 a and the guide curved surface 32 b of the collision wall 32 is used as a means for more reliably preventing water scattering without increasing the size of the scattering prevention wall. A water draining edge 35 is formed in the portion, the collision surface 32a is discontinuous with the guide curved surface 32b, and the collision surface 32a has a convex shape protruding about 1 mm further toward the ejection nozzle 20 than the guide curved surface 32b. According to such a configuration, as shown in FIG. 13, even when the flow rate of the jet water flow from the jet nozzle 20 in the air is small and the momentum of the water flow flowing in the radial direction after colliding with the collision wall 32 is relatively weak, The water flow can be more reliably received by the scattering prevention wall 33 without being pulled by the guide curved surface 32b.

  The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example, the anti-scattering wall does not have to be cylindrical, and it is sufficient if it covers at least the upper part of the collision wall. In the above embodiment, the step portion provided in the middle of the orifice is formed over the entire circumference. However, as shown in FIG. 14, the step portion 29 is provided only in a part in the circumferential direction, and the cross section of the second orifice portion 23b is the key. A groove-like structure can also be used. In this case, since the bubbles are supplied only from a part in the circumferential direction, the bubbles tend to be biased to one side within the cross section of the water flow. This embodiment is effective when, for example, it is desired to generate bubbles concentrating on a specific position.

DESCRIPTION OF SYMBOLS 20 Jet nozzle 22 Bath water inlet 23 Orifice 23a 1st orifice part 23b 2nd orifice part 25 Intake hole 29 Step part 32 Colliding wall 32a Colliding surface 32b Guide curved surface

Claims (5)

A squirting water flow containing bubbles is ejected into a tub from a squirting nozzle provided with a tubing water introduction port to which tub water in the tub is supplied and an orifice provided downstream of the tubing water introduction port. In the bubble generator,
The orifice has a first orifice portion on the upstream side and a second orifice portion provided on the downstream side of the first orifice portion and having a cross-sectional area larger than that of the first orifice portion. A negative portion formed on the back side of the stepped portion is provided at the downstream end of the one orifice portion with a stepped portion that expands the cross-sectional area at least partially in the circumferential direction, and an intake hole for introducing air into the orifice. An air bubble generating device characterized in that an opening is formed in a pressure region and air is sucked by a negative pressure generated on the back side of the stepped portion.   2. The bubble generator according to claim 1, wherein the intake hole is formed so as to straddle the step portion.   3. The bubble generating device according to claim 1, wherein the step portion is formed over the entire circumference of the orifice, and an air layer generated in the negative pressure region on the back side of the step portion during operation is formed over the entire circumference of the orifice. An air bubble generating device characterized by that.   4. The bubble generating device according to claim 1, wherein the back surface of the stepped portion is formed in an acute angle in a sectional view with respect to the inner peripheral surface of the orifice.   The bubble generating device according to any one of claims 1 to 4, further comprising a flow passage that communicates the bath water inlet and the orifice, and the first orifice portion is continuously provided at a downstream end of the flow passage via a stepped portion. The bubble generating apparatus is characterized in that the cross-sectional area of the downstream end of the flow passage is at least twice the cross-sectional area of the first orifice portion.

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