Abstract:
An air entrainment spa nozzle having a jet of water which passes over an air entrainment port with the air entrainment port having a downstream structure which enhances the air entrainment. In one embodiment, the air enhancement structure is a ramp which extends in a downstream direction from the air entrainment port. In another embodiment, the air entrainment port projects or protrudes into the jet of water by a predetermined amount.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is the subject of provisional application Serial No. 60/217,378 filed Jul. 11, 2000 entitled AIR ENTRAINMENT TECHNIQUES FOR SPA NOZZLES. 
    
    
     BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION 
     This invention relates to spa nozzles having air entrainment and more particularly to fluidic spa nozzles having air entrainment. 
     It is common practice to provide an air line to spa nozzles for aeration of exhausting water. The air typically is drawn by the water through the venturi effect of the flowing water, and sometimes air is supplied under pressure from an air pump. See U.S. Pat. Nos. 5,495,627, 5,457,825, 5,444,879 and 5,238,585. 
     The present invention is directed to a method and apparatus for increasing entrainment volume. The invention is directed to an air entrainment spa nozzle wherein a jet of water passes over an air entrainment port and air entrainment is enhanced by a ramp surface extending in a downstream direction from the air entrainment port. In a preferred embodiment, a fluidic oscillator causes sweeping motions of the jet of water and has a pair of control ports immediately downstream of the power nozzle. In one embodiment, the control ports are part of a crossover-type fluidic oscillator having feedback passages, and the entrainment port is located at the exit of an oscillation chamber. In another fluidic embodiment, an inertance loop interconnects the control ports to induce oscillation of the jet of water, and the air entrainment port is located immediately downstream of the control ports. 
     Other fluidic oscillators may be used in practicing the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, advantages and features of the invention will become more apparent when considered with the following specification and accompanying drawings wherein: 
     FIG. 1 shows one preferred embodiment of the invention where the air inlet is at the exit of a crossover-type feedback fluidic oscillator spa nozzle, 
     FIG. 2 shows the invention which comprises the addition of a ramp starting from the downstream end of the outlet, tapering down towards the air inlet port and terminating at the air inlet, 
     FIG. 3 is an enlarged view of the nozzle exit throat/air inlet area, 
     FIG. 4 is a sectional view showing the ramp and air inlet, 
     FIG. 5A is a top plan view of a further embodiment of the invention, FIG. 5B is a side elevational view, FIG. 5C is a sectional view through lines BB of FIG. 5B, FIG. 5D is a front elevational view, and FIG. 5E is a sectional view through lines AA of FIG. 5D, 
     FIGS. 6 and 7 correspond to FIG.  5 E and show different embodiments of the invention wherein the air entrainment port is located immediately downstream of the control port, and the entrainment port protrudes into the flow by differing amounts. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The embodiments of the invention shown in FIGS. 1-4 is in connection with a conventional feedback fluidic oscillator having a power nozzle  10  which is supplied with water from a source  11  and projects a jet of water past control ports  12  and  13  into a crossover oscillation chamber  14 . The fluidic oscillator is of the type having attachment walls  15  and  16  and curved downstream walls  17 ,  18  and a downwardly tapered floor F (FIG. 4) leading to an outlet throat  19  and feedback entranceways  20 ,  21 . When assembled in the housing (not shown), the feedback ports  20 ,  21  couple with feedback passages  22 ,  23  to control ports  12  and  13  to constitute a conventional feedback-type fluidic oscillator. In normal operation, the power jet expands sufficiently to fill the outlet throat  19  before the interaction region and the oscillation feedback channels begin to fill. Vortices are formed on either side of the water jet, but, since two vortices cannot exist simultaneously with equal intensity, one vortex becomes dominant, and the jet or power stream will be diverted against the opposite wall. Assuming it is against the sidewalls  17 , the water flows along the sidewall  17  and through the exit aperture  19  exiting to the right in FIG.  1 . At the same time, fluid enters the feedback entranceway  20  and feedback passage  22  to direct a control signal through control port  12  to cause the jet to detach from attachment wall  15  and switch jet or crossover to the opposite side to repeat the process. Thus, the jet of water sweeps in the outlet apertures  19 , right and left, back and forth as is well known in the art. Pin P 1  and socket SO lock the oscillatory unit in a housing (not shown). All units and component parts are preferably made of molded plastics, but metal moldings are within the scope of the invention. 
     THE PRESENT INVENTION 
     The present invention is directed to the air inlet port  25  and the structure of the surfaces downstream thereof. Referring now to FIG. 2, the outlet comprises a pair of diverging sidewalls  30 ,  31  which, structurally, define the limits of the sweeping jet of water and a top wall (top wall not shown) and bottom wall which contain air inlet port  25 . In this embodiment of the invention, the ramp R, starting from the downstream end DE of the outlet and tapering down towards the air inlet hole  25  and terminating at the air inlet, enhances air entrainment. 
     It has been found that without the ramp R, the entrainment of air almost ceases when the nozzle was immersed beyond a certain depth. Air entrainment was brought up to satisfactory levels by adding the ramp R. 
     The following table shows the vacuum generated by adding the ramp. The tests were run at 15 psi at a depth of 28″: 
     
       
         
               
               
             
           
               
                   
               
               
                 Ramp Angle 
                 Vacuum 
               
               
                   
               
             
             
               
                 14° 
                 6 to 7 inches water 
               
               
                 20° 
                 20 inches water 
               
               
                 25° 
                  8 inches water 
               
               
                   
               
             
          
         
       
     
     As is readily seen from the above, there is a range of ramp angles beyond which the vacuum decreases. This technique can be used for any type fluidic oscillator or even a jet-type spa nozzle to induce entrainment. 
     Referring now to FIGS. 5A-5E, a fluidic oscillator of the inertance-loop-type is shown. In this type of fluidic oscillator, an interaction region IR having an upstream end and a downstream end. A power nozzle PN at the upstream end projects a jet of water into the interaction region IR. First and second control ports CP 1  and CP 2  at each side of the upstream end of the interaction region IR and at each side of the jet of water projecting into the interaction IR by the power nozzle PN are interconnected by a continuous inertance loop CL. The inertance loop CL may be varied in length (or include a variable fluidic circuit component) to vary the frequency of oscillation. The interaction region is defined by a pair of diverging sidewalls SW 1 , SW 2 , diverging floor and ceiling walls FW and CW, with the upstream end of the diverging sidewalls SW 1  and SW 2  being connected directly to the upstream wall forming the control ports CP 1 , CP 2 , respectively. Mounting flange MF and mounting bezel MB are provided for mounting in the spa tub. In operation, the water jet leaving the power nozzle PN interacts with the inertance loop CL to cause the jet of water to oscillate back and forth between the sidewalls S 1  and S 2  at a frequency determined by the continuous inertance loop CL, and the oscillating frequency is essentially proportional in the flow of water through the power nozzle PN. The higher the flow rate, the higher the frequency. 
     An air input port AP is positioned just downstream of the control port CP 1  and CP 2  and has a protrusion PT on a downstream side thereof. This downstream structure PT enhances air entrainment. 
     In some embodiments, such as in the embodiment shown in FIGS. 5A-5E, an optional splitter S (shown in dash lines) can be used to separate the two extreme output jet positions and provide alternating slugs of water for different massaging effects. 
     These embodiments show the entrainment port located immediately downstream of the control ports CP 1 , CP 2  which, in contrast to the earlier embodiment, which shows the invention relative to the crossover-type fluidic (where the output jet flows in opposite directions to the jet exiting from the power nozzle). The arrangements shown in FIGS. 5A-5E,  6  and  7  can be used or without the splitters. These configurations show the entrainment port protruding into the flow by different amounts. When the entrainment port was flush with the floor, the vacuum generated was low, approximately 9 inches of water, while with the port protruding about {fraction (1/32)} of an inch, the vacuum was 100 inches of water. 
     While preferred embodiments of the invention have been shown and illustrated and described in detail, it will be appreciated that many modifications, adaptations and changes can be made to the invention without departing from the basic spirit and scope of the present invention.