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CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/861,227, filed on Nov. 27, 2006, entitled Shower Additive Dispenser, the prior application is herewith incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to chemical dispensers. More specifically, to an additive dispenser attachable to a showerhead or a shower pipe. 
     2. Description of the Related Art 
     Attachment devices for showerheads are well known and provide a method for dispensing an additive such as aromatic oil or medication into shower water. The devices previously proposed either lack the ability to accurately control the flow rate of the additive, aromatic oil or medication, into the water, or those devices that provide such control generally are of very complex construction and, hence, are too expensive to manufacture. Furthermore, they are cumbersome to use and take up considerable space. 
     For instance, U.S. Pat. No. 4,358,056 discloses a method to control the rate by which the additive is introduced into the water prior to the water entering the showerhead, i.e. the additive is mixed with water under pressure. However, the device requires the use of a mixer coupling and three different valves. An additional disadvantage of this and many similar devices described in the prior art is that the additive is mixed with the water prior to the water entering the showerhead. Most commercial showerheads are fitted with various parts made of synthetic rubber, and additives such as aromatic oils cause significant swelling of these rubber parts, thus causing damage to the showerhead. 
     U.S. Pat. No. 4,131,232 and 6,923,384 disclose two very similar liquid additive dispensing devices in which the additive is added to the shower water after the water exits the showerhead. Both devices use gravity as the force to cause the flow of the additive from a reservoir into the shower water. However, with both devices the additive flows into the water stream as discrete droplets, which is undesirable in many applications. For instance, in one potential type of application, namely aromatherapy, the amount of aromatic oil that is needed for a shower of typical duration is extremely small, generally of the order of less than 0.5 ml per minute or approximately 10 drops per minute. Therefore, if the oil is added in the form of discrete droplets, the aroma effect will be very intermittent, with a sudden burst of strong aroma followed by a period of several seconds with no aroma, a result, which is generally undesirable. 
     Furthermore, none of the above-mentioned patents disclose a specific method for controlling the flow rate of oil. Simple valves such as needle valves or pinch valves are not capable of providing adequate flow control at the very low flow rates that are required to dispense aroma oils or other additives such as medication. Electronically operated valves may provide adequate control of the flow rate, but such valves are too expensive for most consumer applications. Accurate and reliable control of the additive flow rate is important in many applications. For instance, in the case where bath oil or essential oil is added to shower water to generate an aroma effect, there is a need to control the flow rate because the intensity of the aroma is influenced by several factors such as the type of oil and the water temperature and the preference for different aroma intensities (strong, medium, mild) varies among users. The need to control the additive flow rate is not limited to essential oils and bath oils, but also applies to other additives such as medications. 
     The present invention provides for a shower additive dispenser which delivers a continuous, i.e. non-intermittent flow of an additive to shower water at extremely low flow rates, and which is capable of controlling the flow rate over a wide range using only one moving part. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a shower additive dispenser, which overcomes the above-mentioned disadvantages of the heretofore-known devices of this general type and which provides a shower additive dispenser that is of simpler construction more versatile and easier to use. 
     The present invention provides for a shower additive dispenser which delivers a continuous, i.e. non-intermittent flow of an additive to shower water at extremely low flow rates, and which is capable of controlling the flow rate over a wide range using only one moving part. 
     With the foregoing and other objects in view there is provided, a shower additive dispenser assembly including an arm member. A receptacle is mounted to the arm member. A body member has a cavity formed therein for retaining a fluid, the body member is removably mounted to the receptacle. A microporous flow restrictor is disposed at the body member. The microporous flow restrictor is configured for allowing the fluid to exit the body member. 
     In accordance with another feature of the invention, the receptacle is pivotably mounted to the arm member for controlling a rate flow of the fluid by defining the angle of the body member. 
     In accordance with an added feature of the invention, the body member has an end with an opening formed therein. The opening is sealed with a foil. The receptacle has a piercing device configured to pierce the foil when the body member is mounted to the receptacle. 
     In accordance with an additional feature of the invention, the piercing device has a cross-shaped cross-section for allowing air to escape the body by flowing along the piercing device. 
     In accordance with yet an additional feature of the invention, the body member is mounted to the receptacle with a bayonet-type connection. 
     In accordance with a further feature of the invention, the microporous flow restrictor is hydrophobic. 
     In accordance with yet another feature of the invention, the microporous flow restrictor is selected from the group consisting of polyethylene and polypropylene. 
     In accordance with yet an additional feature of the invention, the arm member is telescopic and is configured to be mounted to a shower supply pipe. 
     With the objects of the invention in view, there is also provided in combination with a receptacle having a piercing device a shower additive dispenser. The dispenser including a body member having a cavity formed therein for retaining a fluid. The body member is configured for being removably mounted to the receptacle. The body member has an aperture formed therein and communicates with the cavity. The aperture is configured for accepting the piercing device. A seal seals the aperture. A microporous flow restrictor is disposed at the body member and is constructed for allowing the fluid to flow from the cavity. 
     In accordance with still a further feature of the invention, the seal is a foil affixed to the body member. 
     In accordance with yet still a further feature of the invention, the body member has tabs for mounting the body member to the receptacle. 
     In accordance with still another feature of the invention, the microporous flow restrictor is cylindrical. The microporous flow restrictor has a portion disposed in the cavity and a portion projecting from the body member. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied as a shower additive dispenser for delivering an additive to shower water, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the shower additive dispenser according to the invention mounted on shower supply pipe; 
         FIG. 2  is an axial cross-sectional view of the shower additive dispenser according to the invention; 
         FIG. 3  is another axial cross-sectional view of the shower additive dispenser according to the invention; 
         FIG. 4  is an axial cross-sectional view of the fourth body member of the shower additive dispenser according to the invention; 
         FIG. 5   a  is an axial cross-sectional view of another embodiment of the shower additive dispenser according to the invention; 
         FIG. 5   b  is a radial cross-sectional view of the present invention, the section taken on the line A-A in FIG. 
         FIG. 6   a  is an axial cross-sectional view of a receptacle fitted to receive the device shown in  FIG. 5   a;    
         FIG. 6   b  is an axial cross-sectional view of the receptacle shown in  FIG. 6   a  in which the receptacle has been rotated 90 degrees from the position shown in  FIG. 6   a;    
         FIG. 6   c  is a radial cross-sectional view of the receptacle, the section taken along the line B-B in  FIG. 6   a;    
         FIG. 6   d  is a radial cross-sectional view of the receptacle shown in  FIG. 6   b , the section taken along the line C-C in  FIG. 6   b;    
         FIG. 7  an axial cross-sectional view showing the dispenser of the second embodiment of the present invention inserted into the receptacle; and 
         FIG. 8  is a perspective view of the shower additive dispenser according to the invention shown in  FIG. 5   a  mounted on shower supply pipe. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIGS. 1 through 4 , a new and improved shower additive dispenser  10  will now be described.  FIG. 2 , shows that the dispenser  10  includes a cylindrical body member  11  having an axial bore  111 . One end of the cylindrical body member  11  has a thread portion  12 , which fits the threads on a neck of an additive reservoir  13 . The other end of the cylindrical body member  11  has a circular opening  212  connected to the axial bore  111 . The circular opening  212  has a diameter slightly larger than a diameter of a micro-porous flow restrictor  14 . Thus, the flow restrictor  14  can be inserted in to the circular opening  212  of body member  11 . The body member  11  is provided with an annular seal groove in the circular opening  212  to seat an o-ring  15 , which serves to prevent leakage through the gap between the body member  11  and the flow restrictor  14 . The axial bore  111  through the body member  11  includes two sections with different diameters. At one end of body member  11 , the bore  111  has a relatively large diameter  111   b , and thus provides a cavity  111   b  with a volume that is approximately the same as the volume of the reservoir  13 . The other and longer section  111   a  of the bore  111  has a diameter that is relatively small, though sufficiently large to allow for air bubbles to escape when oil flows through the bore. For this purpose the minimum size of the diameter of the longer section  111   a  of the bore  111  is approximately ⅛ inch, and preferably 5/32 inch. For reasons explained in more detail below, it is desirable that the diameter of the longer section  111   a  of the bore  111  is no larger than necessary to allow air bubbles to escape when the additive flows through the bore  111 . 
     The micro-porous flow restrictor  14  is a cylinder, which is made of sintered particles. The material of construction may be a plastic such as polyethylene or polypropylene, a ceramic or a metal such as bronze or stainless steel. Micro-porous flow restrictors  14  made from plastic offer the advantage of being inexpensive. In addition, when the flow restrictor  14  is constructed from a hydrophobic material such a polyethylene or polypropylene, the flow restrictor  14  can be exposed directly to the shower water without affecting the flow of additive through the flow restrictor  14 . However, micro-porous flow restrictors  14  made of plastic are less durable and also become stained from color bodies commonly present in essential oils. Thus, flow restrictors  14  made from plastic are more suitable for use in a disposable device such as described below in the second embodiment of the present invention. Flow restrictors  14  made from metals or ceramics are preferred for use in devices that are intended for repeated use such as the device described in the first embodiment of the present invention. However, in contrast to flow restrictors  14  made from hydrophobic plastics, flow restrictors  14  made from metals and ceramics generally should not be exposed directly to the shower water because the presence of water on the surface of these materials may interfere with the flow of additive through the flow restrictor  14 . 
     The rate by which the additive flows through the flow restrictor  14  is determined by the porosity of the flow restrictor  14 , the dimensions and geometric shape of the flow restrictor  14 , and the hydrostatic pressure exerted by the fluid column above the flow restrictor  14 . In addition, the flow rate is also determined by how far the flow restrictor  14  extends into body member  11 . For the purposes of this invention it has been determined that the pore size of the flow restrictor  14  should be in the range of 0.5 to 90 microns and more preferably in the range of 5 to 35 microns for flow restrictors  14  with a diameter between ⅛ inch and ¼ inch and a length of between ½ inch and 2 inches. The end of the flow restrictor  14  which projects from the body member  11  has a threaded bore  114  which is adapted to fit the threading of a tip  16 , which is also referred to as the liquid dispensing tip. The end of tip  16 , which is attached to flow restrictor  14 , has a diameter, which is substantially exactly the same as the diameter of the flow restrictor  14 . The tip  16  and the flow restrictor  14  are attached to each other seamlessly, so that the liquid additive, which permeates through the surface of the flow restrictor  14 , flows downward over the surface of tip  16 . The opposite end of tip  16  is shaped like a cone. The tip  16  may be fabricated from a variety of materials including, but not limited to metals, plastics and ceramics. The surface texture of tip  16  should be slightly roughened so as not to be smooth. This allows that the liquid additive that flows downward on its surface to be a continuous thin film rather than discrete droplets. 
     A cap  17  is provided to cover the end of the micro-porous flow restrictor  14  which projects from the body member  11 , so that it does not become exposed to the shower water, which could otherwise interfere with the permeation of the additive through the flow restrictor  14 . One end of the cap  17  has a threaded opening that is fitted to a male threading on the body member  11 . The other end has a narrow aperture through which the tip  16  protrudes. 
     As shown in  FIGS. 1 and 3 , the body member  11  is provided with a small aperture  18 , which serves as a vent to allow air into the upper cavity  111   b  of body member  11  when the liquid additive flows out of the device. The exact location of aperture  18  will be discussed in further detail below. 
     As shown in  FIG. 2 , the body member  11  is attached to mount member  19  via cylindrical pin  20 . One end of pin  20  is affixed permanently to the body member  11 . The mount member  19  is provided with an aperture, which is adapted to fit the pin  20 . 
     The pin  20  is provided with a groove  21 , which circumscribes the pin  20  by approximately 180 degrees. As depicted in  FIG. 4 , a threaded hole in mount member  19  is configured to fit a threaded screw  22 , which fits into the groove  21 . Thus, when the screw  22  is screwed into the threaded aperture of mount member  19 , it limits the degree to which body member  11  can be rotated relative to mount member  19 . Thus, when body member  11  and the mount member  19  are initially aligned with both members in a vertical position, body member  11  can be rotated only 180 degrees relative to mount member  19 , that is from an initial position in which the tip  16  points directly upwards and the reservoir  13  points downwards to the exact opposite position, or vice versa. When body member  11  is positioned so that socket  12  faces downward, the reservoir  13  can be attached to body member  11 , and by subsequently turning body member  11  upside down, the liquid additive is transferred from the reservoir  13  to the upper cavity  111   b  of body member  11  without spilling any material. In this regard it is important to point out that aperture  18  should be located in such a position that the liquid does not flow out of aperture  18  when it is transferred from the reservoir  13  to the upper cavity  111   b  of body member  11 . For instance, if the dispenser  10  is set up in such a way that it must be rotated counter-clockwise in order to transfer the additive from the reservoir  13  to the upper cavity  111   b  of body member  11 , then aperture  18  should be disposed so that it faces the direction of movement of the lower portion of body member  11 . 
     As is shown in  FIGS. 1 and 2 , mount member  19  is affixed to a piece of flexible tubing or arm member  23 , which at the other end is attached to the shower pipe via clamp  24 . The flexible tubing allows for the movement of the dispenser  10  into and out of the shower water stream. 
     When using the dispenser  10 , the body member  11  is turned to a vertical position with socket  12  pointing downwards. The reservoir  13 , loaded with the liquid additive, is screwed into socket  12  and body member  11  is rotated to a position where the tip  16  points downward. The rotation causes the liquid additive to flow from reservoir  13  into the upper cavity  111   b  of body member  11  and subsequently through the narrow bore  111   a  of body member  11 , which communicates with flow restrictor  14 . When the liquid permeates the flow restrictor  14 , it appears as a thin film on the exterior surface of the flow restrictor  14 . The film gradually flows downwards to cover the entire surface of the tip  16 . When the tip  16  is inserted into the shower water stream, the film is continuously washed away, and the additive is dispersed into the water stream. 
     The liquid additive flows through flow restrictor  14  due to the hydrostatic pressure exerted by the column of fluid above the flow restrictor  14 . When the liquid is transferred into the cavity  111   b  of the body member  11 , most of the liquid is located in the upper cavity  111   b  of the body member  11 , and only a small portion of the liquid occupies the space in the narrow section of the bore  111   a  through the body member  11 . Thus, as the liquid is dispensed, the hydrostatic pressure and, therefore, the flow rate remains relatively constant until most of the liquid has been consumed, because the height of the liquid column in the upper cavity  111   b  is relatively small compared to the total height of the column. That is why the diameter of the narrow bore  111   a  through the body member  11  should not be any larger than the minimum required to allow air bubbles to escape when the device is filled with liquid additive. In the first embodiment of the present invention, the volume of the large cavity  111   b  in the body member  11  accounts for 50 to 90% and more preferably for 75 to 85% of the total internal volume of body member  11 . The length of the narrow bore  111   a  in the body member  11  is between 1 and 8 inches and more preferably between 2 and 6 inches. 
     The flow rate through the flow restrictor  14  is at its maximum when the dispenser  10  is in a vertical position with the tip  16  pointing downward. To reduce the flow rate, the body member  11  is rotated so that it forms an angle with the mount member  19 , which is held in a vertical position. The tilting of the body member  11  reduces the effective hydrostatic pressure exerted by the liquid column above the flow restrictor  14 . For instance, if body member  11  is tilted to a position to form a 45-degree angle with the mount member  19 , the flow rate is reduced to approximately 70% of the flow rate achieved when the body member  11  is held in a vertical position. At a 60-degree angle, the flow rate is reduced to approximately 50% and so forth. 
     Any liquid additive that remains in the dispenser  10  after the shower water has been turned off can be returned to reservoir  13  and thus saved, simply by rotating the dispenser, so that the reservoir  13  is facing downwards. This will cause the liquid to drain from the dispenser into the reservoir  13 . 
     With reference to  FIGS. 5   a  and  5   b ,  6   a  through  6   d , and  7 , the preferred embodiment of the present invention, will now be described. As is shown in  FIG. 5   a , the dispenser  10  has a hollow body member  11 , which in one end has a circular opening with a diameter slightly larger than the diameter of the micro-porous flow restrictor  14 , so that the flow restrictor  14  can be inserted in to the bore of body member  11 . The body member  11  is provided with an annular seal groove  411  to seat o-ring  33 , which serves to prevent leakage through the gap between the body member  11  and the flow restrictor  14 . The other end of the body member  11  is provided with an aperture  44 , which serves as a vent to allow air into the device so that the liquid contained in body member  11  can flow through the micro-porous flow restrictor  14 . Prior to use, the aperture  44  is covered by an adhesive foil  144 , which prevents the additive from flowing out through the micro-porous flow restrictor  14 . Alternatively, it is possible that the body member  11  is not provided with a through aperture  44 . In this case, the end of the body member  11  may be formed with a score or thinning which defines a perimeter. The perimeter defines a panel or button that is displaced when body member  11  is inserted into the receptacle  116 . This creates the aperture  44  defined by the perimeter. 
     As mentioned above, the micro-porous flow restrictor  14  is made of sintered particles and can be fabricated from a range of materials including plastics, metals, and ceramics. Being relative inexpensive, plastic is the preferred material for use with the device described in the preferred embodiment of the present invention, as it is used only once. The micro-porous flow restrictor  14  is cylindrical in shape and can be either a solid cylinder or a hollow cylinder closed on one end (blind ended flow restrictor) as depicted in  FIG. 5   a  and  FIG. 7 . 
     As shown in  FIGS. 5   a  and  5   b , the body member  11  is provided with tabs  115 , which fit into slots  117  in the receptacle  116  in a bayonet type connection shown in  FIGS. 6   a  through  6   d . Receptacle  116  has a threaded aperture  118 , so that it can be attached to a piece of flexible tubing, the other end of which can be attached to the shower pipe in a similar fashion as shown in  FIG. 1 . The receptacle  116  is fitted with a pointed piercing device  119 , which extends all the way through the upper portion of the receptacle  116 . The radial cross section of piercing device  119  is shaped like a cross as shown in FIG.  6   d , so that air can move through the piercing device  119 . The body member  11 , having a cavity or chamber  511 , now filled with liquid additive, is inserted into receptacle  116  and is turned one quarter turn so it attaches to the receptacle  116  and is held in place by tabs  115  as depicted in  FIG. 7 . When the body member  11  is inserted into the receptacle  116 , the pointed end of piercing device  119  penetrates the adhesive foil  144 , which covers aperture  44  and thus allows air to enter the cavity of body member  11 , so that the additive contained in the body member  11  now can flow through flow restrictor  14 . As the additive flows through flow restrictor  14 , it appears as a film on the surface of the flow restrictor and is continuously washed away by the shower water without formation of droplets. The device described in this embodiment of the present invention is intended for use only one time and is disposed after use. However, the size can be adjusted so that the device can be used multiple times while still being disposable. Thus, in this case, the micro-porous flow restrictor is preferably made from an inexpensive material such as polyethylene or polypropylene or similar plastic materials. Since micro-porous structures made from polyethylene or similar polyolefins generally are very hydrophobic, direct exposure of the flow restrictor  14  by the shower water does not interfere with the flow of the additive through the flow restrictor. Therefore, it is unnecessary to cover the portion of the flow restrictor  14  that protrudes from the body member  11 . 
     In use, the body member  11  is attached to receptacle  116  by inserting it into the receptacle and turning it a quarter turn. Body member  11  is then placed in a vertical position and in such a way that the flow restrictor  14  reaches into the water flowing from the showerhead. As the water washes away the thin film of additive on the surface of the flow restrictor  14 , the additive is homogeneously mixed with the water. In one application of the device, the additive may be an aromatic oil or a mixture of aromatic oils. When the aromatic oil is mixed with the shower water, an aroma therapeutic effect is produced. When the liquid additive is exhausted, the body member  11  is removed from receptacle  116  and is discarded. 
     The rate by which the additive flows through the flow restrictor  14  is at its maximum when the dispenser  10  is in a vertical position with the flow restrictor  14  pointing down. Tilting the device to a position between vertical and horizontal reduces the flow rate. For instance, if the body member  11  is tilted to a position to form a 45-degree angle with the vertical position, the flow rate is reduced to approximately 70% of the flow rate that is achieved when the body member  11  is held in a vertical position. The body member  11  can be tilted into a horizontal position in which the flow is completely stopped. The flow rate can also be adjusted by moving the flow restrictor  14  further in or out of the body member  11 . Generally, when the flow restrictor  14  is moved further into the body member  11 , the flow rate increases and vice versa. 
       FIG. 8  shows the dispenser  10  of the second embodiment mounted to a shower supply pipe  100 . However, the arm  23  can just as easily be mounted to a wall surface of the shower. The dispenser includes an arm  23 , which can be telescoping so as to allow a positioning of the body member  11 . At the end of the arm  23  opposite its mounting to the shower/shower supply pipe, the receptacle  116  is mounted in a pivotable manner to the arm  23 , using a pin or screw as indicated above.

Summary:
A shower additive dispenser assembly including an arm member. A receptacle is mounted to the arm member. A body member has a cavity formed therein for retaining a fluid, the body member is removably mounted to the receptacle. A microporous flow restrictor is disposed at the body member. The microporous flow restrictor is configured for allowing the fluid to exit the body member.