Abstract:
A capillary system for a fluid indicator includes a fluid restrictor, and a capillary tube. The fluid restrictor has a small aperture formed therethrough. The capillary tube is adapted to receive a fluid. The fluid restrictor is sealingly affixed into at least one end of the capillary tube so that the small aperture communicates between the inside of the capillary tube and the outside of the capillary tube. The capillary tube is optionally treated so that an inner surface is oilophobic and hydrophobic. The system better controls the interface or meniscus  14  between the fluids contained in the capillary tube, preventing mixing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/567,497, filed Dec. 6, 2011, the content of which is incorporated herein by reference thereto. 
     
    
     COPYRIGHT &amp; LEGAL NOTICE 
       [0002]    A portion of the disclosure of this patent document contains material which is subject to copyright protection. The Applicant has no objection to the facsimile to reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. Further, no references to third party patents or articles made herein are to be construed as an admission that the present invention is not entitled to antedate such material by virtue of prior invention. 
       BACKGROUND OF THE INVENTION 
       [0003]    This invention relates to hydraulic fluid systems, and in particular, hydraulic systems used in consumer products in which at least two fluids occupy a single container, and the level of the interface between the fluids is to be adjusted. 
         [0004]    What is needed is a means of limiting fluid flow or restricting it to a controlled flow so that the fluids do not mix when a meniscus between the fluids is moved. 
       SUMMARY OF THE INVENTION 
       [0005]    A capillary system is provided for a fluid indicator. The system includes at least one fluid restrictor, and a capillary channel or tube. The fluid restrictor has a small aperture formed therethrough. The capillary tube is adapted to receive at least two immiscible fluids. The fluid restrictor is sealingly affixed into at least one end of the capillary tube so that the small aperture communicates between the inside of the capillary tube and the outside of the capillary tube. The capillary tube is optionally treated so that an inner surface is oilophobic and hydrophobic. A fluid is pumped through the fluid restrictor into the capillary tube to move the meniscus formed between the fluids contained therein. 
         [0006]    An object of the invention is better control of the interface or meniscus between the at least two fluids contained in the capillary tube, preventing mixing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1A  is a top view of the fluid restrictor of the invention. 
           [0008]      FIG. 1B  is a cross-sectional side view of the fluid restrictor of the invention. 
           [0009]      FIG. 1C  is a perspective view of the fluid restrictor of the invention. 
           [0010]      FIG. 2A  is a top view of a first alternate embodiment of the invention. 
           [0011]      FIG. 2B  is a side view of the first alternate embodiment of the invention. 
           [0012]      FIG. 3A  is a top view of a second alternate embodiment of the invention. 
           [0013]      FIG. 3B  is a side view of the second alternate embodiment of the invention. 
           [0014]      FIG. 4A  is a top view of a third alternate embodiment of the invention. 
           [0015]      FIG. 4B  is a side view of the third alternate embodiment of the invention. 
           [0016]      FIG. 5  is a cross sectional side view of a fourth alternate embodiment of the invention. 
           [0017]      FIG. 6  is a perspective view of ends of the capillary tube of the invention, with fluid restrictors installed in the ends thereof. 
           [0018]      FIG. 7  is a partial cross sectional view of the ends of the capillary tubes in which the fluid restrictors are installed. 
           [0019]      FIG. 8  is a perspective view of a fluid restrictor installed half way into an end of a capillary tube. 
           [0020]      FIG. 9  is a flow chart of the method of making the invention. 
           [0021]      FIG. 10  is a perspective view of a fluid restrictor installed into an end of a capillary tube, in which there is an inadequate seal. 
           [0022]      FIG. 11  is a perspective view of a fluid restrictor with an O-ring installed thereon, at an end of a capillary tube. 
           [0023]      FIG. 12  is a flow chart of alternate method of making the invention. 
           [0024]      FIG. 13  is a table of representative menisci created depending on the speed and viscosity of fluid flow. 
       
    
    
       [0025]    Those skilled in the art will appreciate that elements in the Figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, dimensions may be exaggerated relative to other elements to help improve understanding of the invention and its embodiments. Furthermore, when the terms ‘first’, ‘second’, and the like are used herein, their use is intended for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. Moreover, relative terms like ‘front’, ‘back’, ‘top’ and ‘bottom’, and the like in the Description and/or in the claims are not necessarily used for describing exclusive relative position. Those skilled in the art will therefore understand that such terms may be interchangeable with other terms, and that the embodiments described herein are capable of operating in other orientations than those explicitly illustrated or otherwise described. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    The following description is not intended to limit the scope of the invention in any way as they are exemplary in nature, serving to describe the best mode of the invention known the inventors as of the filing date hereof. Consequently, changes may be made in the arrangement and/or function of any of the elements described in the exemplary embodiments disclosed herein without departing from the spirit and scope of the invention. 
         [0027]    Referring now to  FIGS. 1A-1C , the fluid restrictors  10 , combined with coating (surface treatment on the ID  11  of a capillary tube  12  which is too thin to be illustrated in the drawings) of the capillary tube  12  provide significant advantages when used in a watch such as that described in WO 2011/021097 A4 (the contents of which are incorporated herein by reference thereto). The restrictors  10  prevent excessively rapid movement of the meniscus  14  between the two fluids  12  and  20  within the tube, especially when setting the time, or during the return cycle at 6 in the morning or evening (i.e., a retrograde system). Indeed, without them, one of the two liquids  16  and  20 , respectively, can disrupt the other, depending on the temperature, by creating a channel  22  in the other. 
         [0028]    Note that in some embodiments, the capillary tube  12  is a capillary channel ( 102 ) (rectangular, triangular or irregular in cross section), formed in a plate ( 100 ), against which the dial ( 86 ) is sealingly affixed, such as shown in FIG. 7 of WO 2011/021097 A4, incorporated herein. Consequently, the term “tube” and “channel” are intended to mean one and the same thing when recited herein. 
         [0029]    The coating improves the behavior of the meniscus  14  against the walls  11  of the capillary and together with an appropriate ratio of the apertures  26  and  34 , helps prevent the disruption of the meniscus  14 . 
         [0030]    The fluid restrictor  10  is preferrably a ceramic or stone but may also be a metal. The fluid restrictor  10  is formed as a cap-shaped element having a flange  24  formed thereon which prevents the fluid restrictor from entering the capillary tube  12  more than a prescribed amount. A tiny hole  26  (a few microns in diameter) in the fluid restrictor  10 , glued on at least one end  30  of the capillary tube  12 , is preferably located along the axis  32  of the fluid restrictor  10 . The function of the fluid restrictor  10  is the stability of the meniscus  14 , and the protection of the system. 
         [0031]    The hole or aperture  26  in the fluid restrictor  10  has a width of between 0.03 and 0.1 mm in diameter. The aperture  34  of the capillary tube  12  has a width of between 0.6 and 1 mm, preferably 1 mm in diameter. Preferably, the ratio between the widths of the hole  26  of the fluid restrictor  10  and that of the capillary tube  12  is 1:5 to 1:15, for fluids having viscocities between 0.3 et 80 cP at room temperature, sea level, and preferably 0.3 a 5 cP. 
         [0032]    Referring now to  FIGS. 2A to 4B , the capillary tube  12  and the fluid restrictor  10  need not have circular inner apertures. In fact, such may be square, triangular, or irregular apertures  26 ′,  26 ″, and  26 ′″, respectively. These may also be adapted to such a non-circular channel ( 102 ) formed in the plate ( 100 ) shown in FIG. 7 of the PCT application incorporated herein by reference. 
         [0033]    Referring now to  FIG. 5 , the hole or aperture  26  of the fluid restrictor  10  is formed such that the exit port of the aperture which exits into the capillary tube  12  enters the capillary tube at an angle to the central axis of the fluid restrictor  10 . This reduces the chances that the incoming stream of fluid will disrupt the meniscus  14 , particularly when the meniscus  14  is near the fluid restrictor  10 , by diverting the flow away from the center of the meniscus  14  to the sides. Still further, several such holes connecting to a single central hole of the fluid restrictor  10  may further help diver the incoming fluid flow away from a center of the meniscus  14 . 
         [0034]    Referring now to  FIGS. 6 and 7 , fluid restrictors  10  of the invention, are shown installed in the ends  30  of a single capillary tube  12  (the tube is curved back on itself) with functionality as described in WO 2011/021097 A4 mentioned above. Referring in particular to  FIG. 7 , ends  30  of the fluid restrictors  10  and capillary tube  12  are shown in cross section, for clarity. 
         [0035]    Referring now to  FIG. 8 , a fluid restrictor  10  is installed half way into an end  30  of a capillary tube  12 , ready to receive a dose of a suitable epoxy. 
       Gluing Tests—Fluid Restrictor to Capillary 
       [0036]    Any number of glues may be used to affix the fluid restrictor  10  to the capillary tube  12 . Two have proven to be particularly effective. “VITRALIT”® 1605 from Panacol AG of Steinbach, Germany, diluted with a thinner, is one and has the following characteristics: “VITRALIT”® is thermally cured (30 min @ 105° C.) and/or UV cured (60 s @ UV-A 60 mW/cm2, thickness step: 0.5 mm). Further, it is a one component epoxy and has a viscosity in the range of 300-500 cPs (@25° C.). 
         [0037]    As for “EPO-TEK”® 301, available from Epoxy Technology, Inc of Billerica, Mass. is thermally cured (1 hr @ 65° C.), is two component (20:5), and has a viscosity in the range of 100-200 cPs (@23° C.), which is significantly lower than “VITRALIT”®. 
         [0038]    Referring now to  FIG. 9 , the gluing procedure involves the following steps: In a first step  40 , plasma cleaning of both capillary and fluid restrictor is performed. In a second step  42 , the fluid restrictor is placed half-way into the capillary tube  12 . In a third step  44 , a drop of glue is placed on the end  30  of the capillary tube  12  with a standard disposable needle In a fourth step  46 , observing to ensure that the epoxy is properly distributed around fluid restrictor  10 . In a fifth step  48 , the epoxy is allowed to penetrate to around the fluid restrictor and into the capillary via capillary action. In a fifth step  50 , the epoxy is allowed to dry or set. 
         [0039]    Note that it has been found that “VITRALIT”® 1605 alone is too viscous to promote capillary action between capillary tube  12  and the fluid restrictor  10 . To be suitable, it should be thinned with an appropriate thinner, whereas “EPO-TEK”®  301  is suitable without thinning. 
         [0040]    Referring now to  FIG. 10 , it has been observed that when the glue does not completely surround the fluid restrictor, unacceptable leakage may result. 
         [0041]    Again, Vitralit® 1605 is too viscous for capillary action between the capillary tube  12  and the fluid restrictor  10 . “EPO-TEK”® 301 is suitable as is. Deposition is critical. If the glue does not surround the fluid restrictor  12 , it is not possible to add glue later, or to add glue via the capillary tube  12 . Note that these tests were performed with capillary tube  12  having an OD of Ø2 mm and an ID of Ø1 mm. 
         [0042]    As for alternative gluing procedures, inserting a small O-ring  52  around the fluid restrictor  12  helps ensure that the aperture  26  in the fluid restrictor  10  is not blocked by the glue. 
         [0043]    Referring now to  FIGS. 11 and 12 , the modified procedure for gluing using the O-Ring  52  includes the following steps. In a first step  60 , both capillary and fluid restrictor  10  and the O-ring are plasma cleaned. In a second step  62 , the O-ring  52  is placed over an end of the fluid restrictor  10 . In a third step  64 , the fluid restrictor  10  is placed half-way into the capillary tube  12  until the O-ring  52  is in contact with the end rim of the capillary tube. In a fourth step  66 , a drop of glue is placed on the exposed circumference of the fluid restrictor  10  with a standard disposable needle or an oil dispenser. In a fifth step  68 , the glue is observed to ensure that it penetrates sufficiently. In a sixth step  70 , the fluid restrictor  10  is fully inserted into the capillary tube  12  and the O-ring  52  is removed. In a seventh step  72 , the epoxy is allowed to dry or cure. O-ring  52  prevents the hole  26  of the fluid restrictor  10  from being clogged by the glue. 
         [0044]    Note as well, that in addition to the fluid restrictor  10 , a coating of the inside surface  11  of the capillary tube  12  is important to reliable and repeatable control of the meniscus  14  between the fluids in the capillary tube. The fluid restrictors  10  prevent a too rapid movement of the meniscus  14 , especially, when the system is used in a watch such as that described in the above identified PCT application, in setting the time, or return at 6 in the morning or evening (retrograde system). Indeed, without these features, the risk is that one of the fluids can create, depending on the temperature, a channel in the other (see  FIG. 13  below). 
         [0045]    The coating allows it to improve the behavior of the meniscus  14  against the walls  11  of the capillary tube  12 . 
         [0046]    It should be appreciated that the particular implementations shown and herein described are representative of the invention and its best mode and are not intended to limit the scope of the present invention in any way. 
         [0047]    As will be appreciated by skilled artisans, the present invention may be embodied as a system, a device, or a method. 
         [0048]    Moreover, the system contemplates the use, sale and/or distribution of any goods, services or information having similar functionality described herein. 
         [0049]    The specification and figures should be considered in an illustrative manner, rather than a restrictive one and all modifications described herein are intended to be included within the scope of the invention claimed. Accordingly, the scope of the invention should be determined by the appended claims (as they currently exist or as later amended or added, and their legal equivalents) rather than by merely the examples described above. Steps recited in any method or process claims, unless otherwise expressly stated, may be executed in any order and are not limited to the specific order presented in any claim. Further, the elements and/or components recited in apparatus claims may be assembled or otherwise functionally configured in a variety of permutations to produce substantially the same result as the present invention. Consequently, the invention should not be interpreted as being limited to the specific configuration recited in the claims. 
         [0050]    Benefits, other advantages and solutions mentioned herein are not to be construed as critical, required or essential features or components of any or all the claims. 
         [0051]    As used herein, the terms “comprises”, “comprising”, or variations thereof, are intended to refer to a non-exclusive listing of elements, such that any apparatus, process, method, article, or composition of the invention that comprises a list of elements, that does not include only those elements recited, but may also include other elements described in the instant specification. Unless otherwise explicitly stated, the use of the term “consisting” or “consisting of” or “consisting essentially of” is not intended to limit the scope of the invention to the enumerated elements named thereafter, unless otherwise indicated. Other combinations and/or modifications of the above-described elements, materials or structures used in the practice of the present invention may be varied or adapted by the skilled artisan to other designs without departing from the general principles of the invention. 
         [0052]    The patents and articles mentioned above are hereby incorporated by reference herein, unless otherwise noted, to the extent that the same are not inconsistent with this disclosure. 
         [0053]    Other characteristics and modes of execution of the invention are described in the appended claims. 
         [0054]    Further, the invention should be considered as comprising all possible combinations of every feature described in the instant specification, appended claims, and/or drawing figures which may be considered new, inventive and industrially applicable. 
         [0055]    Multiple variations and modifications are possible in the embodiments of the invention described here. Although certain illustrative embodiments of the invention have been shown and described here, a wide range of changes, modifications, and substitutions is contemplated in the foregoing disclosure. While the above description contains many specific details, these should not be construed as limitations on the scope of the invention, but rather exemplify one or another preferred embodiment thereof. In some instances, some features of the present invention may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the foregoing description be construed broadly and understood as being illustrative only, the spirit and scope of the invention being limited only by the claims which ultimately issue in this application.