Abstract:
A hair color delivery system includes a flexible bottle, a dispensing cap having a tapered nozzle, an asymmetric bi-directional valve assembly, and a dispensing tube. The valve assembly comprises a platform, and a pair of valves, comprising tapered extensions through which fluid may be expelled from the bottle and ambient air may enter the bottle. The valves are offset from each other so that they are not co-axial or rotationally symmetric. The delivery system enables a method of substantially continuous delivery of a fluid chemical, yielding a hair treatment that it is easy and safe to use in which the tapered nozzle stays fully charged with product as air can be admitted to a dispensing bottle through a different valve than that used for dispensing.

Description:
FIELD 
     The disclosure pertains to devices and methods for storing and dispensing fluids. More particularly, the disclosure pertains to a flexible hair color bottle for mixing and applying fluid hair color chemicals using an asymmetric, bi-directional valve assembly. 
     BACKGROUND 
     The success of a hair color treatment depends on safe and controlled application of chemical dyes in a timely manner. Such chemical dyes, especially fluids, or those that contain volatile components such as solvents, may be allergenic, irritating, or even toxic if handled incorrectly. In addition, chemical dyes of the type used in hair color products can leave permanent stains if they are spilled on clothing, furniture, countertops, or floors. Moreover, skin can become stained or irritated if the color is allowed to make contact with bare skin for prolonged periods. 
     Hair color products are typically packaged with detailed application instructions, but it is often left up to the professional hair colorist to assemble the necessary tools for applying the product safely and consistently. For example, some instructions direct the user of the product to mix chemicals in a glass or plastic container, and to apply the chemical with a brush. If an open container such as a color bowl is used, product may be lost to evaporation and the resulting fumes may be unpleasant or even unsafe. Hair products intended for consumers are generally packaged with a color bottle or other application tools along with hair color (dye) and developer (peroxide). Consumers at home may be supplied a brush that is attached to the hair bottle to create lighter streaks in the hair or to retouch grey roots. While application with a brush typically permits better control and is appropriate for salon applications, brush application is difficult for consumers and home users of hair color almost always use a bottle having a short cone for product delivery. 
     The success of a hair color treatment relies on the precision of the application to the areas of the hair one desires and the speed at which one can apply the color. The color/dye is stored in a separate container from the developer/peroxide which activates the color when the two are mixed together. The dye and peroxide solutions are mixed immediately before application and as soon as the developer and color are mixed, a chemical process begins that changes the quality of the finished product. As the mixed product ages, it becomes more oxidized and less effective. In products intended to lighten hair color, the capability of the product to lighten decreases as the mixed product ages. Products intended to darken hair color, produce darker, muddier, and less attractive hair color as the mixed product ages. Consequently, the speed at which the product is applied can determine the quality of the resulting hair color. The degradation of the dye/peroxide mixture is especially problematic for home consumers who typically must rapidly, accurately, and uniformly apply the mixture to their own hair to produce satisfactory results. 
     Some hair color products are shipped with a small squeeze bottle having a screw cap closure with a simple cone-shaped nozzle that must be inverted to apply the product. Such a method of delivery is cumbersome for self-use, slows the delivery process, and is prone to leakage and spills. Furthermore, after initially squeezing the bottle, and upon release of manual pressure, a one-way nozzle tends to suck product back into the bottle while the air pressure is equilibrating, thus interrupting continuous flow of product during application. Also, in the case of fluids of higher viscosity or gels, some product inevitably remains in the bottom of the bottle and is wasted. 
     In general, fluid chemicals such as cleaning fluids or laboratory chemicals are often packaged and sold in, or may be mixed and stored by a user in, flexible squeeze bottles made from a soft, high density polyethylene. Some laboratory squeeze bottles have a wide mouth that is easy to fill, and that is covered by a screw cap having a conical tapered polypropylene nozzle coupled to a tube (pickup tube) that extends into the fluid reservoir. The tapered nozzle provides a simple way either to control the application of fluid chemical, or to use the chemical as a wash. The user controls the amount of fluid dispensed by simply squeezing the flexible bottle. Such bottles are, however, prone to dripping and chemical evaporation in response to changes in ambient air temperature and barometric pressure. Also, they must be maintained in an upright position, or the fluid will simply spill out of the dispensing cap. What is needed for safe and effective application of hair color products is a hair color delivery system suitable for mixing and storing the product in a closed container, and for applying the hair color in a continuous and controlled manner in either a salon setting or at home. 
     Existing vented squeeze bottle valves (for example, annular valves of the type commonly used for sports drinks or condiments) typically exhibit axial or rotational symmetry so that outside air passes through the cap around the perimeter of the dispenser as fluid chemical is squeezed out of the dispenser. Conventional dispensing bottles include those disclosed in U.S. Pat. No. 5,125,543 to Rohrbacher, U.S. Pat. No. 4,133,457 to Klassen, and U.S. Pat. No. 4,408,702 to Horvath, U.S. Pat. No. 4,474,314 to Roggenburg and U.S. Pat. No. 4,747,518 to Laauwe. 
     SUMMARY 
     The present disclosure concerns hair color bottled equipped with dispensing caps containing a bi-directional valve assembly that lacks axial or rotational symmetry. A hair color delivery system includes a flexible bottle, a dispensing cap having a tapered nozzle, an asymmetric bi-directional valve assembly situated between the flexible bottle and the dispensing cap, and a tube having a proximal end coupled to the valve and a distal end that extends into the flexible bottle. The dispensing cap is secured to the mouth of, and preferably seals, the flexible bottle, for example, by a threaded closure and using a portion of the valve assembly as a gasket situated between the bottle mouth and the dispensing cap. 
     According to some examples, asymmetric bi-directional valve assemblies used to dispense fluid from within a container include a platform for covering an opening to the container, an exit valve comprising a first tapered extension in the platform, and a first aperture through which fluid may be expelled from the container in an outward direction along a first axis, and an input valve comprising a second tapered extension in the platform, preferably opposing the first tapered extension, and a second aperture through which ambient air may enter the container in an inward direction along a second axis. The first and second axes are offset, or spaced apart, from each other, so that the valves are not co-axial. The tapered extensions are preferably in the shape of circular or flattened cones, having top openings that may be circular or linear slits, respectively. 
     Representative methods of substantially continuous delivery of a fluid to a target area include the steps of providing a flexible bottle, at least partially filling the flexible bottle with the fluid, expelling fluid from the flexible bottle, in response to application of external pressure on the flexible bottle by directing the fluid through a first tapered extension, dispensing the fluid to the target area through a tapered nozzle, and permitting air to enter into the flexible bottle through a second tapered extension spaced apart from, and opposing, the first tapered extension, so as to adjust internal and external pressures on the flexible bottle, thereby maintaining a supply of fluid in the tapered nozzle. When the fluid is a hair coloring agent, delivery of the coloring agent as disclosed results in a safe and effective hair color treatment. 
     There are many advantages of the disclosed methods and the disclosed systems. For example, it is easy and safe to accurately self-apply the hair color, while holding the bottle upright to reduce the chance of drips or spills. The tapered nozzle stays fully charged with product because, due to the bi-directional valve assembly, the tapered nozzle does not admit air when pressure is removed from the bottle. An opaque, closed bottle protects chemical from light and evaporation, and has a stylish appearance for use in salons. Such a bottle also protects the color product from exposure to air. A tapered nozzle also acts to cleanly part the hair, and may be used to spread the product along hair shafts. In other examples, transparent or translucent materials are used. Finally, the tube ensures that chemical remaining at the bottom of the bottle is accessible, to reduce waste. 
     The foregoing and other features, and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a pictorial side elevation view of a stylized representative example of a hair color bottle showing interior parts, including a hollow dispensing tube, a dispensing screw cap assembly that includes a tapered nozzle, and an asymmetric bi-directional valve assembly. 
         FIG. 2  is an exploded view of the hair color bottle of  FIG. 1 . 
         FIG. 3  is a top plan view of the dispensing screw cap assembly shown in  FIGS. 1-2 . 
         FIG. 4  is a side elevation view of the dispensing screw cap assembly shown in  FIGS. 1-3 . 
         FIG. 5  is a bottom perspective view of the dispensing screw cap assembly shown in  FIGS. 1-4 . 
         FIG. 6  is a perspective view of the asymmetric, bi-directional valve assembly shown in  FIGS. 1-2 . 
         FIG. 7  is a bottom plan view of the asymmetric bi-directional valve assembly shown in  FIG. 6 . 
         FIG. 8  is a schematic cross-sectional view of the asymmetric bi-directional valve assembly shown in  FIGS. 6-7 . 
         FIG. 9  is a bottom plan view of a representative asymmetric bi-directional valve assembly in which end slits of opposing outward and inward tapered extensions are perpendicular with respect to one another. 
         FIG. 10  is a bottom plan view of a representative asymmetric bi-directional valve assembly in which end slits of opposing outward and inward tapered extensions are parallel and along a common axis. 
         FIG. 11  is a flow diagram showing steps in a method of substantially continuous delivery of fluid to a target area. 
     
    
    
     DETAILED DESCRIPTION 
     As used in this application and in the claims, the singular forms “a,” “an,” and “the” include the plural forms unless the context clearly dictates otherwise. Additionally, the term “includes” means “comprises.” Further, the term “coupled” does not exclude the presence of intermediate elements between the coupled items. 
     The disclosed systems, devices and methods described herein should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and non-obvious features and aspects of the various disclosed embodiments, alone and in various combinations and sub-combinations with one another. The disclosed systems, devices, and methods are not limited to any specific aspect or feature or combinations thereof, nor do the disclosed systems, devices, or methods require that any one or more specific advantages be present or problems be solved. Any theories of operation are to facilitate explanation, but the disclosed systems, devices, and methods are not limited to such theories of operation. The disclosed hair color delivery system is furthermore not limited to use with hair color chemical or health and beauty products. The terms “fluid,” “chemical,” “hair color,” and “coloring agent” are meant to encompass fluids, water, mixtures, gels, slurries, pastes, and other flowing substances that may be ejected from a container by means of pressurization. The examples below are described with reference to hair colorants, but the disclosed apparatus can be used to dispense other materials as well. 
     According to some examples disclosed herein, a color bottle is provided for use as held in an upright position. Such an upright bottle can allow the person applying hair treatment products greater visibility and access to hard to reach areas, permitting easier application. Constant flow of color product through a delivery nozzle can provide consistent product flow, permitting more precise application. A two-way valve allows product to be applied more quickly with better results because there is no pause to allow air to depart from the chamber that retains the color product. A long tapered nozzle allows the user to cleanly part the hair before squeezing the color along the root line, and reach difficult areas more readily. In addition, the shaft of the nozzle may also be used as a tool to spread the product along the hair shaft. With such color bottles, the average home consumer may be able to reduce application time on their hair color and achieve greater accuracy. Because the color product can be less oxidized with the improved application speed that the disclosed methods and apparatus can provide, hair color results can be improved. More measured, precise application also reduces product dripping and mess, providing a more satisfactory consumer experience. The examples below pertain to a color bottle with a single nozzle assembly, but additional nozzles (such as interchangeable nozzles) can be provided as well. 
     With reference to  FIGS. 1-2 , a representative example of a stylized hair color delivery system  100  is configured to facilitate directing and controlling the application of hair color products. Delivery system  100  comprises a flexible bottle  102 , a dispensing screw cap assembly  104 , and an asymmetric bi-directional valve assembly  106  that attaches to a proximal end  107  of a hollow delivery tube  108  having a distal end  110  that extends into the bottle  102 . According to a representative example, the bottle  102  has a circularly cylindrical shape that may feature tapered shoulders  112  and a tapered base  114 . However, the shape of the bottle  102  generally does not influence utility of the delivery system  100  and therefore containers such as the bottle  102  can be provided in arbitrary shapes. Embodiments of the bottle  102  are characterized by their flexibility, and in particular their elastic flexibility, so that when the bottle  102  is deformed by application of external pressure, the bottle  102  recovers from the compression and can return to an original shape, or at least partially return towards an initial shape or volume. Suitable elastic materials for the bottle  102  include but are not limited to low-density polyethylene-type materials commonly used for squeeze bottles. The volume capacity of the bottle  102  may reasonably be, but is not limited to, a range of volumes up to about 1 liter, wherein smaller bottles might preferably be packaged with hair color products for end user consumers, and larger bottles might preferably be sold to professional colorists or salons. Unlike conventional chemical wash bottles that are typically transparent or translucent, stylized hair color bottle  102  is preferably opaque, and available in a variety of designer colors and textures, with or without labels or indicia. However, the bottle  102  can be transparent or translucent. 
     Dispensing screw cap assembly  104  preferably features a tapered nozzle  115  for directing the release of hair color chemical contained in the bottle  102  and is configured to be coupled to the dispensing tube  108 . The tapered nozzle  115  is shown as part of the screw cap assembly and can be formed in a molding process with other portions of the screw cap assembly  104 , but in other examples, the tapered nozzle  115  can be a separate piece that is secured to the screw cap assembly  104 . The bottle  102  preferably has a threaded mouth  116  for accommodating corresponding threads  118  on the screw cap assembly  104 . The bottle mouth  116  has a circular cross section that fits the interior threads  118  that can be molded into an inside surface  120  of the screw cap assembly  104 . The screw cap assembly  104  may have an outer perimeter  122  of arbitrary shape, for example, egg-shaped as shown in  FIG. 2 . Furthermore, the top surface  124  of the screw cap assembly  104  may be horizontal or tilted from horizontal with the bottle  102  in an upright position, and sides  126  of the screw cap assembly  104  may be vertical or tilted with the bottle  102  in an upright position, and the sides  126  can be straight or curved. As shown in  FIG. 2 , apertures  127 ,  128 ,  129  are provided in the screw cap assembly. The aperture  128  permits gas flow in and out of the bottle  102  so as to manage pressure adjustment in the bottle  102 . The apertures  127 ,  129  are configured to receive corresponding protrusions  127 A,  129 A in the valve assembly  106  so as to prevent or impede rotation of the valve assembly  106  as the dispensing cap assembly  104  is secured to the bottle  102 . The aperture  128  is generally configured to admit air to the bottle  102 . 
     With reference to the exploded view of delivery system  100  of  FIG. 2 , the valve assembly  106  is situated between the flexible bottle  102  and the screw cap assembly  104 . The valve assembly  106  comprises a disc-shaped platform  200 , an exit valve  202  configured to extend into the screw cap assembly  104  and an input valve  204  configured to extend into the bottle  102 . The disc-shaped platform  200  may be sized to substantially match the size of the opening of mouth  116 , so that platform  200  is secured to the mouth  116  of bottle  102  preferably forming a seal between the bottle  102  and the screw cap assembly  102 . The platform  200  preferably is formed of an elastic material so as to serve as a compliant gasket. 
       FIGS. 3-5  illustrate additional features of the screw cap assembly  104 . In the top plan view shown in  FIG. 3 , the shape of the outer perimeter  122  is visible, as are the positions of the aperture  128  that is provided to admit air or other gas into the bottle  102  when the bottle recovers from compression. The aperture  128  is situated to be coupled to the input valve  204  and the apertures  127 ,  129  are configured to receive protrusions  127 A,  129 A on the valve assembly. The screw cap assembly  104  preferably includes tapered nozzle  115  as a fixed portion of the assembly, and the nozzle  115  typically includes a tapered segment  300 , a tip segment  301 , and an elbow segment  302 . As shown in  FIG. 4 , the elbow segment  302  is preferably bent at an elbow angle  400  that exceeds 90 degrees so that, when the delivery system  100  is held upright, hair colorant or other product can be dispensed in a convenient direction. For delivery of hair colorant products, horizontal delivery or delivery at a slight upward angle with respect to horizontal is convenient. Typical upward angles from the horizontal are in ranges from 0 degrees to about 30 degrees, such as 0 to 30 degrees, 0 to 10 degrees, or 0 to 5 degrees. The elbow angle  400  can be selected so that an upward delivery angle of 5-45 degrees is provided with the bottle  102  held upright. This arrangement permits convenient dispensing. 
     The sectional view of  FIG. 4  shows the interior structure of the screw cap assembly  104 , specifically, the degree of taper along the length of nozzle  115 , and the degree of taper within the tip segment  301 , where hair colorant product or other materials exit the delivery system  100  for application to a target area. The screw cap assembly  104  includes a hollow space  402  for receiving the threaded mouth  116  of the bottle  102 . Referring to the bottom perspective view of  FIG. 5 , the screw cap assembly  104  also includes an aperture  500  at which elbow segment  302  joins screw cap assembly  104  and configured to receive the exit valve  202 . 
     A magnified perspective view in  FIG. 6  illustrates details of a representative embodiment of the asymmetric bi-directional valve assembly  106 . Each of the two valves, exit valve  202  and input valve  204 , is formed by an aperture in platform  200  and a corresponding tapered extension. For example, the input valve  204  is formed by the intake aperture  128  and an inward tapered extension  601 , and the exit valve  202  is formed by an exit aperture (not visible in the view of  FIG. 6 ) and an outward tapered extension  602 . The exit valve  202  includes an outward tapered extension  602  that extends along a first axis  604  to linear end slit  605  in an exit surface  606 . The exit surface  606  is configured to direct fluid from the hollow tube  108  into the tapered nozzle  115 . The slit  605  is configured to open in response to a positive pressure applied to the interior of the exit valve  202  and otherwise to remain substantially closed. Typically, the exit valve  202  is formed of a flexible, elastic material that is responsive to slight pressure provided by compression of the bottle  102 . A lower portion  607  of exit valve  202  is configured to attach snugly to the proximal (top) end  107  of the tube  108 . The exit valve  202  also includes a reinforcing collar  608  that extends outward form the platform  202  and is coupled to the outward tapered extension  602 . 
     As shown in  FIG. 6 , the tapered extension  602  of the exit valve  202  includes opposing flat surfaces such as surface  603 A and curved or cylindrical surfaces such as surface  603 B. Surfaces such as the surface  603 A generally taper from the platform  200  to the exit surface  605  so that the exit surface  605  is approximately rectangular. Curved surfaces such as the surface  603 B can be similarly tapered. A taper angle and overall length of the tapered extension  602  can be selected as convenient, and generally so as to be accommodated by the elbow segment  302  of the nozzle  115 . If desired, an external diameter of the reinforcing collar  608  is selected to seal to the nozzle  115  as secured to the bottle  102 . 
     Similarly, the input valve  204  is typically configured to admit air from outside the bottle  102  via the air intake channel  600  through an inward tapered extension  601  that extends along and is tapered with respect to a second axis  609  which is offset from the first axis  604 . The axes  609  and  604  are typically but not necessarily parallel. Accordingly, the tapered extensions  601  and  602  are generally oppositely directed, but they need not be anti-parallel. Entry of air into the bottle  102  through the narrow linear end slit  608  tends to equalize internal and external air pressures exerted on bottle  102 , and maintains a headspace above the fluid reservoir within bottle  102 . To prevent or reduce twisting or rotation of valve assembly  106  in the attachment of the screw top assembly  104  to the bottle  102 , the valve assembly  106  includes the protrusions  127 A,  129 A that are configured to be inserted into corresponding apertures  127 ,  129  in the screw top assembly  104 . The valve assembly  106  is preferably made of silicone or of a similar flexible elastic, chemically inert material. In some examples, the valve assembly is formed as a single piece in a molding or other process. Alternatively, input and exit valves and a suitable gasket platform can be formed separately, and retained in a suitable configuration as attached to a bottle. Input and exit valves can have the same dimensions, or can be different. Typically, neither of the valves is centered with respect to an axis of the bottle as assembled, but, if convenient, an input or exit valve can be centered. 
     In  FIG. 7 , a bottom plan view is presented, showing the various openings in the underside of disc-shaped platform  200  that supports the valve assembly  106 . The orientation of slits  605  and  610  is understood to be substantially parallel in this representative example. An air intake channel  600  may have a different circumference than the circumference of the base of tapered extension  202 . 
     Referring to  FIG. 8 , a cross-section of valve assembly  106  is shown, highlighting further structural asymmetries between exit valve  202  and input valve  204 .  FIG. 8  shows internal dimensions of the valves  202  and  204  relative to a first tip cavity  800  and a second tip cavity  802 , respectively, that comprise valve passageways through which fluids such as hair colorants or gases such as air move in response to compression and relaxation of the bottle  102 . The volume of the tip cavities  800 ,  802  can be based on desired dispense pressures or volumes, bottle sizes, or different dispense material viscosities. According to one embodiment, walls  822 ,  824  of the valves  202 ,  204 , respectively, meet at a junction  808 , the location of which does not coincide with the platform  200 . As shown in  FIG. 8 , the thickness of the wall  822  of the valve  202  at the reinforcing collar  608  is preferably greater than that a thickness of the wall  824  of the valve  204 . The thickness of the wall  822  of the valve  202  at the reinforcing collar  608  is generally non-uniform, tapering so as to become thinner from the junction  808  in both directions. The reinforcing collar  608  also elevates the base of the outward tapered extension  602  of the valve  202  above the platform  200  whereas the location of the base of inward tapered extension  601  of the valve  204  coincides with platform  200 . 
     In general, valve assemblies may include a pair of opposing tapered extensions of arbitrary relative orientation. Referring to  FIGS. 9-10 , additional exemplary alternative embodiments of valve assemblies are shown in which pairs of opposing tapered extensions have different orientations. For example, according to one alternative embodiment shown in  FIG. 9 , a valve assembly  900  includes a first valve  902  and second valve  904  that include slits  903 ,  905 , respectively, that are configured to control fluid flow. The slits  903 ,  905  extend along perpendicular axes  908  and  910 , respectively. The valves  902 ,  904  extend from a compliant platform  906  that can serve as a gasket. The valve  902  includes a tapered extension  912  having flat surfaces  912 A,  912 B that taper from the platform  906  to the slit  903  and curved tapered surfaces  912 C,  912 D. The valve  904  can be similarly constructed, and the valve assembly  900  can be formed as a single molded part, or constructed of separated valves and gasket. 
     An alternative representative valve assembly  1000  is illustrated in  FIG. 10 . The valve assembly includes a gasket base  1002  configured to provide a seal between a color bottle and dispensing cap. Valves  1004 ,  1006  are provided for delivery of a product such as a hair color product from the bottle and admission of air to the bottle. The valve  1004  includes a tapered portion  1008  having an approximately circular cross section at the gasket base and a substantially rectangular cross-sectional area at an exit surface  1010 . In some examples, portions of tapered extensions that define valves retain some curvature at the exit surface. For convenience, surfaces such as the exit surface  1010  are referred to as substantially rectangular as any curvature in shorter sides increase surface perimeter by less than about 20%, 10%, or 5% and when viewed, tend to appear rectangular. 
     As shown in  FIG. 10 , sidewall sections  1011 A- 1011 B of the valve  1004  correspond approximately to portions of a conical surface, while sidewall sections  1012 A- 1012 B are defined by flat surfaces that taper to the exit surface  1010 . The sidewall sections  1011 A- 1012 B can be formed of a flexible material having a constant or variable thickness, and are conveniently formed in a molding process that includes formation of the gasket base  1002 . The valve  1006  can be similarly constructed, and in the example of  FIG. 10 , includes an exit slit and exit surface  1005  situated along a common axis  1020  with the exit surface  1010 . For convenient illustration, exit slits in the valve exit surfaces are not shown in  FIG. 10 . Typically two valves and the gasket base  1002  are formed as a single molded part, but one or more or all can be formed separately by a molding or other fabrication process and secured as needed. 
     Slits in the exit surfaces  1010 ,  1005  permit fluid passage in response to a pressure difference between a pressure at the gasket base and at the exit surfaces. The valves are formed of a suitable flexible, elastic material so that such a pressure difference causes the slit to open and then to close when the pressure difference is removed. A slit length and exit surface area can be selected so as to permit ready delivery of a hair color product or other material in response to pressures available upon hand compression of a squeeze bottle. The valve assembly  1000  can also include a cylindrical extension (not shown in  FIG. 10 ) that is configured for coupling to a tube that extends into a bottle to receive a hair color or other product. However, such an extension can be omitted, and the tube coupled directly to the gasket base  1002 . 
     The representative valve assembly  1000  is shown as a flattened, cylindrical taper, but other shapes can be used. For example, a conical taper can be used, and a circular exit surface can be provided with a rectangular slit for fluid passage. Other exit surface treatments can also be used in which exit surface can provide an aperture for fluid passage in response to pressure and remain sealed in the absence of pressure. In addition, a slit or other prospective exit surface opening need not be centered in the exit aperture, and the exit aperture need not be centered with respect to an input aperture. 
     As shown in the examples, the bottle cap and a delivery tube are of one piece, unitary construction, but other arrangements can be used. For example, a bottle cap can be provided with one or more apertures to be fluidically coupled to a delivery tube that is provided as a separate part and, for example, retained against the gasket when the cap is secured to the bottle. 
     In the examples above, fluid delivery is via a rectangular slit aligned on a rectangular exit surface, but in other examples, exit slits can be provided on circular, ovoid, polygonal exit surfaces or exit surfaces of other shapes. 
     With reference to  FIG. 11 , a representative method  1100  by which a user may achieve substantially continuous delivery of a fluid to a target area includes a step  1102  in which a flexible bottle is provided. In a step  1104 , the bottle is at least partially filled with a fluid to be dispensed. At  1106 , a user positions the bottle so that a fluid delivery nozzle tip is situated at a suitable location (for example, a location at which hair colorant is to be applied). The bottle can be held substantially upright and external pressure is applied to the bottle at  1108  so as to expel fluid from the bottle. At  1112 , pressure can be released from the bottle so as to admit air into the bottle while retaining the fluid to be dispensed in the fluid delivery nozzle, even at the tip of the nozzle. If additional fluid such as hair colorant is to be applied, steps  1106 - 1112  can be repeated until the supply of fluid is exhausted or until selected areas are treated. The method  1100  applies generally to delivery of a fluid to a target area, for example, as an improvement in applications in which conventional squeeze bottles are used (e.g., food service, laboratory chemical use, and the like). In a specific example, the method  1100  provides steps by which a consumer can safely and effectively apply hair colorant with uniform delivery of a coloring agent without having to refill a dispensing nozzle every time a bottle is fully compressed and is allowed to return to its uncompressed shape. 
     In view of the many possible embodiments to which the principles of the disclosure may be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting the scope of the disclosure. We therefore claim all that comes within the scope and spirit of the appended claims.