Abstract:
A microbubble system comprises a pipe network defining an inner passage for flow of fluids in a longitudinal direction, the pipe network adapted to receive a fluid and having an outlet connected to a tub for outputting the fluid into the tub. A pump in the pipe network induces a flow of the fluid into the tub. A gas intake in the pipe network or in the pump configured for inletting gas into the flow of the at least one fluid into the tub. A reduction member is transversely positioned inside the inner passage to block same, the reduction member downstream of the pump, the reduction member defining a plurality of longitudinally oriented passages each having a microbubble-size throat.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority on U.S. Provisional Patent Application No. 61/987,202, filed in May 1, 2014, the contents of which are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present application relates to fluid injection systems for tubs. 
       BACKGROUND OF THE ART 
       [0003]    Tubs are well known for their primary use, namely a washroom installation in which a user person washes and bathes. Tubs have, however, evolved to add pleasure and comfort to practicality, and are found in many forms, such as bathtubs, spas and whirlpools. 
         [0004]    Massage systems of various configurations have been provided to inject fluids, such as air or water, into the liquid of the tub, so as to procure a massaging effect for the occupant of the tub. One particular type of air injection system is referred to as a microbubble technology. Microbubble technology refers to the injection of gas bubbles in the water, which gas bubbles are micro-sized. For example, microbubbles are defined as being smaller than one millimetre (0.039 in) in diameter, but larger than one micrometre (3.9×10 −5  in). Due to their size, microbubbles may in some instances penetrate skin pores, to exfoliate the skin and remove toxins, among other benefits. Microbubble technology exposes the bather to oxygen-rich water. It however remains a challenge to produce such microbubbles and equipment typically used for such purpose is complex. 
         [0005]    For sterilization purposes, when a gas with bactericidal activity such as ozone is used, the local impact and heat generated when the bubble breaks also improve the effect of sterilization. Polluting substances rise to the surface and are decomposed due to the microbubbles, thereby helping to cleanse the water. 
       SUMMARY 
       [0006]    It is an aim of the present disclosure to provide a microbubble system that addresses issues associated with the prior art. 
         [0007]    Therefore, in accordance with the present disclosure, there is provided a microbubble device for creating microbubbles in a tub, the microbubble device comprising: at least one pipe section defining an inner passage for flow of fluids in a longitudinal direction; at least a first mixing member transversely positioned inside the inner passage to block same, the first mixing member defining at least one passage longitudinally oriented and adapted to be below a top liquid surface circulating in the inner passage, the at least one passage being larger than microbubbles; a reduction member transversely positioned inside the inner passage to block same, the reduction member spaced apart and downstream of the first mixing member, the reduction member defining a plurality of longitudinally oriented passages each having a microbubble-size throat. 
         [0008]    Further in accordance with the present disclosure, there is provided a microbubble system comprising: at least one pipe network defining an inner passage for flow of fluids in a longitudinal direction, the pipe network adapted to receive at least one fluid and having an outlet connected to a tub for outputting the at least one fluid into the tub; a pump in the pipe network for inducing a flow of the at least one fluid into the tub; at least one gas intake in the pipe network or in the pump configured for inletting gas into the flow of the at least one fluid into the tub; and a reduction member transversely positioned inside the inner passage to block same, the reduction member downstream of the pump, the reduction member defining a plurality of longitudinally oriented passages each having a microbubble-size throat. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a schematic view of an assembly of a tub and of a microbubble system in accordance with the present disclosure; 
           [0010]      FIG. 2  is a perspective view of an embodiment of the assembly of the tub and the microbubble system of  FIG. 1 ; 
           [0011]      FIG. 3  is a partially sectioned longitudinal view of a filtering assembly of the microbubble system of  FIG. 1 ; 
           [0012]      FIG. 4A  is an assembly view of a venturi unit of the microbubble system of  FIG. 1 ; 
           [0013]      FIG. 4B  is an assembly view of the venturi unit with gas injection unit of the microbubble system of  FIG. 1 ; 
           [0014]      FIG. 5  is an exploded view of a microbubble device of the microbubble system of  FIG. 1 ; 
           [0015]      FIG. 6  is an enlarged view of disks of the microbubble device of  FIG. 5 ; 
           [0016]      FIG. 7  is a perspective view of a converging disk of the microbubble device of  FIG. 5 ; 
           [0017]      FIG. 8  is a perspective view of an aerator disk of the microbubble device of  FIG. 5 ; 
           [0018]      FIG. 9A  is a perspective view of a reduction disk of the microbubble device of  FIG. 5 ; 
           [0019]      FIG. 9B  is a sectional view of the reduction disk of the microbubble device of  FIG. 5 ; 
           [0020]      FIG. 10A  is a perspective view of an embodiment of a vent unit of the microbubble system of  FIG. 1 ; and 
           [0021]      FIG. 10B  is a perspective view of another embodiment of a vent unit of the microbubble system of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Referring to the drawings and, more particularly, to  FIG. 1 , there is illustrated at  10  a microbubble system used in assembly with a tub A. The microbubble system  10  is configured to operate a microbubble-producing cycle, in which a flow of microbubble-rich liquid is injected in the tub A, e.g., with gas bubbles smaller than one millimetre (0.039 in) in diameter, but larger than one micrometre (3.9×10 −5  in). The tub A is any appropriate type of tub having a bathing cavity conceived to receive therein a liquid such as water. The tub A may be a bathtub, a whirlpool, a spa, among many other possibilities and names. The tub typically comprises a wall having an exposed surface forming the bathing cavity and an undersurface, the latter referred to as a hidden surface when the tub A is embedded in its surroundings. Numerous components of the microbubble system  10  are concealed under the tub and thus not visible, unless indicated otherwise. 
         [0023]    Referring to  FIGS. 1 and 2 , the microbubble system  10  is shown in a configuration in which liquid from the tub A is collected, subjected to the microbubble-producing cycle, and reinjected in the tub A in a microbubble-rich state. The microbubble system  10  has an inlet(s)  11 A and one or more outlets  11 B, which are defined through the tub wall and are thus visible in the inner cavity of the tub A. The inlet  11 A is used to the collect liquid from the tub A to expose the liquid to the microbubble-producing cycle, while the outlet(s)  11 B returns the liquid with microbubbles in the liquid of the tub A. Another component that may be visible is an interface of an electronic controller unit of the microbubble system  10 . As a few components of the microbubble system  10  are electrically powered, an electronic controller unit featuring a processor may be connected to all operable components to operate the microbubble system  10  in producing microbubbles in the liquid of the tub. For simplicity, the electronic controller unit is not shown in the figures, but is typically provided with a keypad accessible to the user to control the operation of the microbubble system  10 . It is also considered to use wireless technology and smart devices to operate the microbubble system  10 . 
         [0024]    Still referring to  FIG. 1 , the inlet(s)  11 A and outlets  11 B are shown interconnected by a plurality of components through a piping network  12 . The piping network  12  is constituted of various pipes, including straight pipe sections, elbows, T-pipes, etc. During the microbubble-producing cycle, the liquid flows from the inlet  11 A to the outlets  11 B, in what is referred to a normal flow direction. 
         [0025]    Referring to  FIGS. 1 and 2 , a filtering unit is provided in the pipe network  12  downstream of the inlet  11 A. The filtering unit comprises a filter  13 , a fluid source  14  and a valve  15 . The filtering unit is an upstream component of the microbubble system  10  that will prevent larger residue (e.g., dirt particles, organic components such hair, etc) from reaching downstream components of the microbubble system  10 . 
         [0026]    A venturi unit  16  is downstream of the filtering unit and allows gas (e.g., air, oxygen, ozone or mixtures thereof) into the liquid stream of the microbubble system  10 , which gas saturates the water of the pipe network  12  to create the microbubbles. The venturi unit  16  may or may not be working in conjunction with a specific gas injection unit (e.g., O 3 ) and uses the pump water suction speed to draw and mix gas into the water stream, by venturi effect. A pump  17  (illustrated with a drain) is downstream of the venturi unit  16  and induces fluid flow in the pipe network  12 , from the inlet  11 A to the outlets  11 B. In the illustrated embodiment, the pipe network  12  will therefore source its liquid from the tub A to reinject same with microbubbles through the outlets  11 B. 
         [0027]    A microbubble device  18  produces the microbubbles with the water circulating in the pipe network  12  with the gas injected by the venturi unit  16 . The pressure resulting from the action of the pump  17  will contribute to the creation of microbubbles by the microbubble device  18 , in forcing the liquid/gas mixture through the microbubble device  18 . A vent unit  19  may also be provided in the microbubble system  10  and is typically downstream of the venturi unit  16  to exhaust any excess gases circulating in the network  12 . 
         [0028]    Referring to  FIG. 3 , there is illustrated an embodiment of the filtering assembly, with the filter  13 , the fluid source  14  and the valve  15  shown in greater detail. The filter  13  is part of the components of the pipe network  12  through which water will flow in the normal flow. The fluid source  14  and the valve  15  branch off from the components of normal flow, and are typically operated when the microbubble-producing cycle is off, in a backwash cycle. The valve  15  may be a solenoid valve or any other valve operated to selectively allow the fluid source  14  to direct fluid on the filter  13 , in a reverse flow direction in comparison to the normal flow direction, i.e., toward the inlet  11 A. Hence, cleaning fluid with dislodge residue from the filter  13  toward the inlet  11 A. The fluid source may be any appropriate source, such as the main water line that injects water in the tub commanded by the valve  15  to create a backwash on the filter  13 . The reverse flow configuration is one of different options that are possible, another one consisting of directing backwash fluid with residue to the drain. Alternatively, a filter  13  may be provided in close proximity to the inlet  11 A, to allow manual removal of the filter  13  for cleaning, when the microbubble-producing cycle is off. 
         [0029]    The filter  13  is shown having a screen  30 . The normal flow direction is indicated as N in  FIG. 3 . The fluid source  14  comprises an injection nipple  40  that points toward the screen  30  but is located downstream therefrom. The nipple  40  is concentrically located in a laid T-pipe  41  also shown in  FIGS. 2 and 4 , which T-pipe  41  is part of the network  12 . During the microbubble-producing cycle, fluid will circulate through the screen  30 , past the nipple  40  and into the branch portion of the T-pipe section  41  downstream relative to the normal flow direction. A bushing  42  holds the nipple  40  in the position shown in  FIG. 3  and in relation with the solenoid valve  15 . This is one possible arrangement among others. The arrangement is convenient in that it may be disassembled, for instance to change the screen  30 . However, the filtering assembly of  FIG. 3  is well suited to be operated autonomously for numerous cycles due to its robustness and simplicity, and because of the backwash cycles operated periodically, such as after each microbubble-producing cycle. It helps in preventing contaminants and solid residue from reaching further components of the microbubble system  10 . 
         [0030]    Referring to  FIG. 4A , the venturi unit  16  is shown in greater detail. The venturi unit  16  is connected to the T-pipe section  41  described previously for the filtering assembly, and is downstream of the filtering assembly, although the venturi unit  16  could be upstream as well. The venturi unit  16  has another T-pipe-like section  60  which is a venturi pipe section with a bushing  61  connected to the perpendicular branch of the venturi pipe section  60 . It is observed that a diameter of the perpendicular branch of the venturi pipe section  60  has a smaller internal size than that of the main section of the venturi pipe section  60 . A bushing  61  may be used to support a pneumatic muffler  62 , or equivalent air control valve. The pneumatic muffler  62  is open to the environment, whereby the negative pressure differential in the perpendicular branch of the venturi pipe section  60 , resulting from the venturi effect caused by the flow of liquid in the main section of the venturi pipe section  60 , will result in air entering the venturi unit  16  via the pneumatic muffler  62 , to mix with the liquid circulating in the venturi unit  16 . The pneumatic muffler  62  or equivalent valve will ensure that a suitable amount of air enters the venturi unit  16 , for instance to avoid pump cavitation. Needle valves, check valves, spring-loaded valves could be used as alternatives to the pneumatic muffler  62 . Likewise, actuated devices like gas injection pumps, etc, could be used as well. 
         [0031]    Referring to  FIG. 4B , another configuration is shown, in which a gas injection unit is also present. A barbed fitting  62 ′ is mounted to the bushing  61 , and is connected to tubing  63  (including the two small tubing sections shown in  FIG. 4B ), which may include an inline needle valve  64 A allowing air entry (i.e., in equivalent fashion to the pneumatic muffler  62  operating with the venturi effect) and/or an inline filter  64 B to receive pressurized gas (e.g., air, oxygen-rich air, ozone) from gas injection unit, such as gas pump  65  (e.g., for instance, an ozonator used in off cycles to clean the system), in one of numerous possible arrangements. The gas pump  65 , whether it is an ozonator, a gas source, an air source, etc, may also be replaced by an aromatherapy gas pump that adds scents (e.g., essential oil vapors) to the gas pumped into the tubing  63 . The tubing  63  is a convenient and practical solution to interconnect the gas pump  65  to the T-pipe  60 . However, other options are considered as well. For instance, rigid pipes may be used for this purpose. Likewise, the assembly of bushing  61 , barbed fitting  62 ′, tubing  63 , valve  64 A and filter  64 B is one of numerous combinations possible to connect the gas pump  65  to the pipe network  12 . 
         [0032]    Referring to  FIGS. 5 and 6 , the microbubble device  18  is shown in greater detail. In the illustrated embodiment, multiple pipe sections are present in the microbubble device  18  so as to form a cartridge-like configuration that may be replaced and disassembled. For instance, the microbubble device  18  may be disassembled without tools. However, the various pipe sections illustrated are one among numerous possibilities. The normal flow direction is shown as N to show a direction of flow of fluids in the microbubble device  18  during the microbubble-producing cycle. The microbubble device  18  has a pipe section  80  that has an internal rim  80 A projecting radially in its inner cavity. The pipe section  80  is received in pipe section  81  of greater diameter, for instance by complementary threading and tapping on the pipe sections  80  and  81 . The pipe section  81  also has an inwardly-projecting rim  81 A. Accordingly, the pair of rims  80 A and  81 A are used concurrently as abutments to hold captive three different disks in the microbubble device  18 . More specifically, there is provided sequentially a converging disk  82 , an aerator disk  83  and a reduction disk  84 . The pair of rims  80 A and  81 A is one of numerous configurations that may be used to keep the disks  82 ,  83 , and  84  captive in the arrangement of  FIG. 6 . The expression disk is used for disks  82 ,  83 , and  84 , as the microbubble device  18  has a generally round section. It is however contemplated to have geometries other than round for the microbubble device  18  (e.g., square, oval, polygonal, etc), in which case the disks  82 ,  83  and  84  could be described as plates, walls, partitions, or the like. However, for simplicity, the expression disk will be used hereinafter, although it encompasses other configurations and shapes. 
         [0033]    Referring concurrently to  FIGS. 6 ,  7  and  8  the converging disk  82  is seated against the rim  80 A, and hence blocks the inner passage defined by the pipe section  80 . The converging disk  82  has a central converging passage  82 A through which fluid must pass to flow downstream of the converging disk  82 . The passage  82 A is defined as central, as it may be concentrically defined in the converging disk  82 A, but may be eccentrically positioned in the disk  82 . In an embodiment, the passage  82 A is spaced from the periphery of the disk  82 , as it is required that the passage  82 A be below a top surface of the water in the pipe section  80  (if any top surface). The passage  82 A is the single opening in the converging disk  82  in  FIG. 7 . It is however considered to have more than one of the passage  82 A in the converging disk  82 . However, the passages, if there are more than one, are again positioned in the converging disk  82  so as to be below the top surface of water in the pipe section  80 . Spacers  82 B project axially from the converging disk  82 . The spacers  82 B are specifically sized to keep the aerator disk  83  at a given distance from the converging disk  82 . 
         [0034]    Referring to  FIGS. 6 and 8 , the aerator disk  83  also blocks the inner passage defined by the pipe section  80 . The aerator disk  83  has a plurality of peripheral passages  83 A. As shown, the peripheral passages  83 A are circumferentially distributed adjacent to the periphery of the aerator disk  83 . In similar fashion to the converging disk  82 , the aerator disk  83  has spacers  83 B projecting axially therefrom to maintain the reduction disk  84  at a predetermined distance from the aerator disk  83 . Due to the size of the spacers  82 B and  83 B, and the thickness of the various disks  82  to  84  as well as the spacing between the rims  80 A and  81 A, the spatial arrangement of disks as in  FIG. 6  is maintained in spite of the fluid pressures to which the disks  82  to  84  are exposed. Other configurations are considered as well, such as annular spacers, additional rims, etc. The above-described configuration is simple in that the disks  82  to  84  are essentially stacked against one another to preserve the desired spacing. 
         [0035]    Referring to  FIGS. 6 ,  9 A and  9 B, the reduction disk  84  also blocks the inner passage defined by the pipe section  80 . The reduction disk  84  has a plurality of passages  84 A. Unlike the disks  82  and  83 , the passages  84 A in the reduction disk  84  are distributed all over the surface of the reduction disk  84 . The passages  84 A are shown as having a substantial increase in diameter along the normal flow direction N, at some point into the reduction disk  84 . Stated differently, the passages  84 A have a first narrower upstream section, and a second wider downstream section. The first narrower upstream section acts as a throat for the gas/liquid mixture entering the passages  84 A of the reduction disk  84 . In the illustrated embodiment, this is done by way of a counterbore arrangement, although other configurations are considered, such as countersink, flaring, etc. The reduction disk  84  has a shoulder  84 B by which the reduction disk  84  will abut against the rim  81 A. This is best shown in  FIG. 6 , and is one of different arrangements possible. 
         [0036]    According to a non-limitative embodiment, exemplary diameters for the passages  84 A of the reduction disk  84  are 0.026 in for the narrower upstream section (long of 0.070 in+/−0.020 in), and 0.070 for the wider downstream section, giving a ratio of about 2.7. The narrower upstream section is a throat that is smaller than 0.039 in, i.e., the microbubble-size threshold. However, some tolerance is possible for the diameters of the passages  84 A, and thus a variation in ratio is possible, for instance with a range of ratios between 2.4 and 3.0. In terms of thickness, the disk  84  may be 0.43 inch thick+/−0.1 inch for example (a ratio of 16.5 thickness to throat diameter, +/−1.5), with an upstream diameter of about 1.55 inch, and a downstream diameter of 1.33 inch. The thickness of the disk  84  is greater than a microbubble size, whereby the passages  84 A have an elongated shape. To maintain the pressure upstream of the reduction disk  84 , there is a limited number of the passages  84 A in the reduction disk  84 . For instance, there may be fewer than 90 passages  84 A for the diameter of 1.55 inch. A suitable range is between 40 and 90 passages  84 A. 
         [0037]    The passages  82 A and  83 A are wider than the passages  84 A, as they are not provided to output microbubbles, unlike the passages  84 A in the reduction disk  84 . For example, the passage  82 A in the converging disk  82  may have a diameter ranging between 0.2 to 0.5 inch, while the passages  83 A in the aerator disk  83  may each have a diameter between 0.16 and 0.18 inch. 
         [0038]    Referring to  FIGS. 10A and 10B , different vent unit configurations are shown. In both embodiments, there is provided a T-pipe section  90 , from which projects a tubing  91  or like pipe that will reach a check valve  92 A in  FIG. 10A  and a vent  92 B in the  FIG. 10B . In the case of the check valve  92 A, the check valve  92 A is provided on a top wall surface of the tub A. The check valve  92 A is of the type that will prevent water from passing therethrough but allow air exhaust. On the other hand, the vent  92 B of  FIG. 10B  is on a vertical wall of the tub A, whereby it does not require a check valve mechanism to prevent water from exhausting therethrough, as water overflowing through the vent  92 B would flow down into the tub A. The T-pipe section  90  may be located in a raised section of the piping network  12 , to maximize the amount of gas that is exhausted by the vent configuration. 
         [0039]    Now that the various components of the microbubble system  10  have been described, an operation thereof will be set forth. The microbubble system  10  should only be operated when there is liquid in the tub A, above a given level, i.e., above the inlet  11 A. Accordingly, the microbubble system  10  may have level sensors to ensure that there is an adequate level of water in the tub. During operation, the pump  17  is operated to induce fluid flow in the pipe network  12  from the inlet  11 A to the outlets  11 B, to operate the microbubble-producing cycle. In the microbubble-producing cycle, water from the tub A entering the system  10  through the inlet  11 A will pass through the filter  13  for solid residue to be removed, and move downstream through the microbubble device  18  and back into the tub via the outlets  11 B. In alternative embodiments, the water may be obtained from a water source, such as the main water line. 
         [0040]    The venturi unit  16  allows gas to be drawn into the flow of water in the pipe network  12 . Alternatively, or supplementally, the gas injection unit  65  is activated in the microbubble-producing cycle, to inject gas in the flow of water in the pipe network  12 . Any timing unit may be used in conjunction with the gas injection unit  65  to control the amount of gas that is injected, to reach adequate gas content in the water, e.g., gas saturation levels. The resulting mixture of liquid and gas is passed through the pump  17 , which pump  17  will perform some additional gas/liquid mixing by its propelling action. 
         [0041]    Upon entering the microbubble device  18 , the gas and liquid will further mix as they are forced through the passage  82 A of the converging disk  82 . As the passage  82 A is below the top surface of water, gas will be forced downwardly through the passage  82 A as gas would have otherwise tend to remain on the surface of the water. Hence, for gas to pass through the passage  82 A, it may have to mix with water. 
         [0042]    The gas/water mixture is then passed through the aerator disk  83  and more specifically through the peripheral passages  83 A thereof. The circumferential arrangement of the passages  83 A, and the diameter of the passages  83 A, may cause the formation of bubbles of non-microbubble size in the water and/or may further mix air and gas. 
         [0043]    The bubbles and/or air/gas mixture in the water resulting from the effect of the aerator disk  83  reach the reduction disk  84 . By passing through the passages  84 A of the reduction disk  84 , the bubbles will be broken down due to the relatively small diameters of the passages  84 A. The subsequent increase in diameter of the passages  84 A will result in reduction of the velocity of the gas/water mixture and in a pressure drop. This in turn will cause the creation of the microbubbles in the water, which microbubble and water will be projected into the tub A by the outlets  11 B. 
         [0044]    In order for microbubbles to be generated, the pump  17  must provide sufficient liquid pressure to cause microbubble formation at the reduction disk  84 . For example, with the dimensions of the passages  84 A described above, the pump  17  may be required to create a pressure at the reduction disk  84  above 10 Psi, for instance in a range between 10 Psi and 52 Psi. In a particular embodiment, a pressure range of 18 to 38 Psi results in microbubbles of preferable quality and quantity. Lower pressures may be suitable for creating microbubbles, but at a slower rate. Moreover, the presence or absence of the gas pump  65  may have an impact on the pressure generated by the pump  17 , whereby this factor is to be taken into consideration when sizing the pump  17 . 
         [0045]    In the event that a backwash is to be performed, the venturi unit  16  and pump  17  are stopped and fluid is injected by operation of the valve  15  through the filter  13 . Therefore, residue will be flowed back into the tub via the inlet  11 A. 
         [0000]    The sizing (e.g., diameter and length) of the various disks  82  to  84  is essential in creating the microbubbles effectively.