Fluid mixing and dispensing system

Abstract

A fluid mixing system and method is disclosed for automatically mixing precise concentrations of photographic processing chemistry to be used in an X-ray film processor. The system produces a fresh batch of mixed solution whenever a previous batch has been reduced to a predetermined minimum volume. A pair of substantially identically constructed mixing units are provided to produce both developer and fixer solutions for film processing. Each unit has: a chemical supply structure for supplying chemicals from containerized supplied; a storage and mixing tank structure which underlies the chemical supply structure and defines a reservoir for mixing the chemistry with water; a water input valve for selectively introducing water under pressure into the tank structure; control apparatus for conditionally controlling operation of the water valve; and a chemical release assembly which is coupled to and actuated by the water valve. The chemical release assembly is operated by the pressure of the water as the water is admitted through the water valve. Operation of the release assembly causes piercing of the containers, allowing the chemistry to drain into the reservoir. The pressurized water creates a swirl for agitating and thoroughly mixing the chemistry and the water.

What is claimed is: 
     
       1. A fluid mixing system, comprising: (a) a reservoir;   (b) a first fluid supply in communication with the reservoir, the first fluid supply including a container for carrying a plurality of vessels, the container having an opening associated with each vessel;   (c) a fluid release assembly disposed intermediate the first fluid supply and the reservoir, the fluid release assembly including a piercing assembly for puncturing the vessels to release the first fluid into the reservoir through the openings;   (d) a second fluid supply in communication with the reservoir and the fluid release assembly, the flow of the second fluid controlling operation of the fluid release assembly;   (e) a valve disposed intermediate the second fluid supply and the reservoir upstream of the fluid release assembly;   (f) a valve control to control the valve and therefore the flow of the second fluid to the fluid release assembly and the reservoir;   (g) a liquid level control means responsive to the level of fluid in the reservoir to activate the valve control when the fluid in the reservoir reaches a predetermined level; and   (h) an interlock switch control means responsive to the presence of the first fluid supply to actuate the valve control when the vessels in the container contain a predetermined amount of fluid.   
     
     
       2. A chemical replenisher system for an X-ray film processor for mixing a developer chemical and a fixer chemical with water to produce a developer solution and a fixer solution to be dispensed to an X-ray film processor, comprising: (a) a fixer tank structure;   (b) a developer tank structure;   (c) fixer supply means associated with the fixer tank structure for providing a predetermined quantity of prepackaged fixer chemical;   (d) developer supply means associated with the developer tank structure for providing a predetermined quantity of prepackaged developer chemical;   (e) fixer water input means connected to the fixer tank structure for coupling water under pressure to the fixer tank structure;   (f) developer water input means connected to the developer tank structure for coupling water under pressure to the developer tank structure;   (g) a fixer chemical release structure associated with the fixer supply means to release the fixer chemical to the fixer tank structure;   (h) a developer chemical release structure associated with the developer supply means to release the developer chemical to the developer tank structure; and   (i) a control apparatus to control the operation of each chemical release structure, the control apparatus including an interlock mechanism actuated upon the presence of the supply means, the fixer interlock mechanism being actuated only when the fixer supply means is associated with the fixer tank structure and the developer interlock mechanism being actuated only when the developer supply means is associated with the developer tank structure.   
     
     
       3. The replenisher system of claim 2, the control apparatus further including a plurality of actuating members attached to the fixer and developer supply means for actuating the respective interlock mechanisms. 
     
     
       4. The replenisher system of claim 2, wherein each control apparatus further includes an indicator mechanism disposed within the tank structure and connected to the control apparatus for indicating the volume of solution in the tank structure, the water input means being actuated only when the interlock mechanism associated with the tank structure has been actuated and the indicator mechanism indicates that the volume of solution in the tank structure has decreased to a predetermined level. 
     
     
       5. The replenisher system of claim 4 wherein each water input means includes a control valve, and each valve is coupled to and controlled by the respective interlock and indicator mechanisms. 
     
     
       6. The replenisher system of claim 2 wherein each tank structure includes a support surface which engages the supply means and the interlock mechanism includes an actuating member which is engaged by the supply means. 
     
     
       7. The replenisher system of claim 6 wherein each supply means comprises: (a) a container having a lower surface which engages the surface of the support, the lower surface having a plurality of spaced openings;   (b) a plurality of chemical-containing vessels disposed within the container and positioned in alignment with the openings; and   (c) first and second actuating members disposed on the lower surface and spaced from each other.   
     
     
       8. A mixing system developer chemicals and fixed chemicals with water to produce fixer and developer solutions for a film processor, comprising: (a) a plurality of fixer chemical supply units, each comprising a portable container within which a plurality of vessels are disposed, each vessel providing a predetermined quantity of a fixer chemical;   (b) a plurality of developer chemical supply units, each comprising a portable container within which a plurality of vessels are disposed, each vessel providing a predetermined quantity of a developer chemical;   (c) a plurality of mixing units for mixing the chemicals with water, each mixing unit including: (i) a tank structure for supporting a supply unit;   (ii) water input means for directing water under pressure to the tank structure;   (iii) a chemical release assembly operated by the water for releasing chemical from the vessels of the supply unit to the tank structure; and   (iv) control apparatus for operating the chemical release assembly and the water input means to provide a predetermined volume of mixed solution within the tank structure; and     (d) the control apparatus of a plurality of like mixing units being interconnected for successively actuating the chemical release assemblies and water input means to provide and maintain concurrently one tank structure having a predetermined volume of fixer solution and another tank structure having a predetermined volume of developer solution, the tank structures supporting like chemical supply units having connected outlets.   
     
     
       9. The mixing system of claim 8 wherein: (a) the control apparatus of each system includes supply indicator means secured to each mixing unit for engagement with the container to indicate when the vessels contain a predetermined quantity of chemical;   (b) a float switch mechanism is disposed within the tank structure to indicate the volume of mixed solution within the tank structure; and   (c) a solenoid is coupled to the indicator means and the float switch mechanism to operate the water input means.   
     
     
       10. The mixing system of claim 9 wherein each chemical release assembly comprises a piercer assembly coupled to the water input means for piercing the vessels in response to the introduction of water from the water input means. 
     
     
       11. The mixing system of claim 10 wherein each chemical supply unit and associated mixing unit includes an interlock mechanism which allows only a fixer chemical supply unit to actuate a fixer chemical unit and a developer chemical supply unit to actuate a developer chemical mixing unit. .[.12. A method of mixing fluids in a reservoir, comprising the steps of: (a) providing a first fluid supply in communication with the reservoir under the influence of gravity;   (b) disposing a fluid release assembly intermediate the first fluid supply and the reservoir;   (c) providing a second fluid supply in communication with the reservoir, the fluid release assembly being disposed intermediate the second fluid supply and the reservoir;   (d) sensing the presence of a predetermined amount of fluid in the first fluid supply and in the reservoir; and thereafter   (e) introducing fluid from the second fluid supply to the reservoir, the flow of the second fluid actuating the fluid release assembly to introduce fluid from the first fluid supply to the reservoir..]. .[.13. The method of claim 12, further including the step of agitating the fluids in the tank..]. .[.14. The method of claim 13, wherein the step of agitating comprises directing the second fluid into the reservoir as a rapidly moving stream..]. .[.15. The method of claim 12, wherein the step of introducing fluid from the second fluid supply is conditioned upon the mixed solution in the reservoir being below a first, predetermined level and upon the first fluid supply containing a predetermined volume of fluid..]. .[.16. The method of claim 15, further including the step of continuing the introduction of the second fluid into the reservoir until the mixed solution has reached a second, predetermined level..]. .[.17. The method of claim 12, wherein the step of providing a first fluid supply includes:   (a) disposing a first fluid in a vessel; and   
     
     
       (b) positioning the vessel overlying the reservoir..]. 18. .[.The method of claim 17, wherein the step of providing a first fluid supply also includes:.]. .Iadd.A method of mixing fluids in a reservoir, comprising the steps of: (a) providing a first fluid supply in communication with the reservoir under the influence of gravity; including: i. disposing a first fluid in a vessel;   ii. positioning the vessel overlying the reservoir;   .[.(a).]. .Iadd.iii. .Iaddend.disposing a container above the reservoir, the container having a plurality of openings; and   .[.(b).]. .Iadd.iv. .Iaddend.inserting a plurality of vessels into the container, each vessel being disposed adjacent an opening.[...]..Iadd.;     (b) disposing a fluid release assembly intermediate the first fluid supply and the reservoir;   (c) providing a second fluid supply in communication with the reservoir, the fluid release assembly being disposed intermediate the second fluid supply and the reservoir;   (d) sensing the presence of a predetermined amount of fluid in the first fluid supply and in the reservoir; and thereafter   (e) introducing fluid from the second fluid supply to the reservoir only if the predetermined amount of fluid in the supply is present, the flow of the second fluid actuating the fluid release assembly to introduce fluid from the first fluid supply to the reservoir. .Iaddend. .[.19. The method of claim 17 wherein the step of introducing fluid from the second fluid supply is conditioned upon the vessel having a predetermined volume of   
     
     
        fluid..]. 20. .[.The method of claim 17 further including the step of.]. .Iadd.A method of mixing fluids in a reservoir, comprising the steps of: (a) providing a first fluid supply in communication with the reservoir under the influence of gravity, including: i. disposing a first fluid in a vessel;   ii. positioning the vessel overlying the reservoir;   iii. .Iaddend.piercing the vessel to release the first fluid into the reservoir.[...]..Iadd.;     (b) disposing a fluid release assembly intermediate the first fluid supply and the reservoir;   (c) providing a second fluid supply in communication with the reservoir, the fluid release assembly being disposed intermediate the second fluid supply and the reservoir.   (d) sensing the presence of a predetermined amount of fluid in the first fluid supply and in the reservoir; and thereafter   (e) introducing fluid from the second fluid supply to the reservoir only if the predetermined amount of fluid in the first fluid supply is present, the flow of the second fluid actuating the fluid release assembly to introduce fluid from the first fluid supply to the reservoir. .Iaddend.   
     
     
            The method of claim 20, wherein the step of piercing comprises advancing a piercer assembly into engagement with the vessel to puncture the vessel, the piercer assembly advancing in responce to flow of the 
     
     
        second fluid. 22. In an X-ray film developing system, a method of mixing and maintaining a predetermined volume of mixed film developing and fixing solutions, comprising the steps of: (a) providing a plurality of mixer units having commonly connected output lines, each unit having a storage tank of the predetermined volume;   (b) providing a prepackaged amount of a first fluid constituent for each mixer unit;   (c) supplying a second fluid constituent under pressure to each mixer unit;   (d) introducing a predetermined volume of the second fluid constituent into the storage tank of each mixer unit and introducing the prepackaged amount of the first fluid constituent into the storage tank for mixing with the second fluid constituent;   (e) depleting the mixed solution in each storage tank to a predetermined level; and   (f) activating a second mixer unit to introduce into its storage tank a predetermined volume of the second fluid constituent and a prepackaged   
     
     
        amount of the first fluid constituent. 23. The method of claim 22, including the step of activating in succession additional mixer units so that the volume of solution in at least one mixer unit stays above the 
     
     
        predetermined level. 24. A mixing system for mixing first and second fluids to produce a mixed solution, comprising: (a) first fluid supply means for providing a predetermined quantity of the first fluid; and   (b) mixing means coupled to the first fluid supply means for mixing the first fluid with the second fluid to produce the mixed solution, the mixing means including: (i) a reservoir for storing the mixed solution;   (ii) second fluid supply means for directing the second fluid under pressure to the reservoir;   (iii) a release assembly for releasing the first fluid into the reservoir;   (iv) support structure for supporting the first fluid supply means, the support structure including a surface having openings through which the release assembly operates and through which the first fluid is supplied to the reservoir; and   (v) a spray head in communication with the second fluid supply means and disposed adjacent the support structure to rinse the support structure     
     
     
        with the second fluid. 25. The mixing system of claim 24, further including control apparatus for operating the second fluid supply means to introduce the second fluid to the spray head substantially coincidentally with the actuation of the release assembly, thereby effecting premixing of the first and second fluids prior to their introduction into the 
     
     
        reservoir. 26. The mixing system of claim 24, further including an agitator assembly disposed within the reservoir to agitate the first and 
     
     
        second fluids. 27. The mixing system of claim 26, wherein the agitator assembly is in communication with the second fluid supply means and introduces the second fluid into the reservoir to cause the mixed fluids 
     
     
        to swirl. 28. In a fluid mixing system for mixing first and second fluids in a reservoir, the system having a supply structure including a vessel in fluid communication with the reservoir for supplying the first fluid to the reservoir, a displaceable fluid release assembly disposed .Iadd.below the vessel .Iaddend.within the reservoir and including a tubular member, the tubular member having a pointed end portion for piercing the vessel and releasing the first fluid, the end portion including a tip, a slicing edge portion, and a fold-over edge portion, the tip and slicing portions providing cutting edges to sever a portion of the vessel to form a discharge opening, the fold-over portion providing inefficient slicing to fold the severed portion to permit the severed portion to remain connected to the vessel by a link, whereby the first fluid is permitted to drain through the discharge opening .Iadd.and through the tubular member .Iaddend.into the reservoir without the severed portion becoming entrained 
     
     
        in the fluid flow. 29. The fluid mixing system of claim 28, wherein: (a) the cutting edge of the slicing portion of each tubular member is inclined at a first, acute angle with respect to the longitudinal axis of the member when viewed from the side;   (b) the edge of the fold-over portion of each tubular member is inclined at a second, larger angle with respect to the longitudinal axis of the member when viewed from the side; and   (c) each member when viewed from the front has a longitudinal slit near the pointed end and circumferentially spaced from the apex of the point for   
     
     
        minimizing coring of the pierced vessel. 30. A fluid mixing system for mixing first and second fluids in a reservoir, the system having a supply structure for supplying the first fluid to the reservoir, and a fluid release assembly disposed within the reservoir, the release assembly including a plurality of hollow members to engage the supply structure to release the first fluid, the release assembly also including: (a) a cylinder; and   (b) a piston disposed within the cylinder and connected to the hollow members, the piston being acted upon by the second fluid to advance the   
     
     
        hollow members into engagement with the supply structure. 31. The fluid mixing system of claim 30, wherein the cylinder includes an exit port to permit a portion of the second fluid to flow to the reservoir to agitate the fluid in the reservoir after the piston has advanced a predetermined 
     
     
        distance. 32. The fluid mixing system of claim 30, further including a rinse mechanism coupled to the release assembly and disposed adjacent the supply structure and wherein the cylinder includes a bypass to permit a portion of the second fluid to flow to the rinse mechanism to premix the 
     
     
        fluids after the piston has advanced a predetermined distance. 33. Film processing chemical mixing apparatus comprising: (a) a chemical mixing structure defining developer and fixer mixing chambers;   (b) a developer supply structure defining a plurality of volumes each for containing a premeasured quantity of a different film developer constituent, the constituents to be mixed to provide a film developer solution;   (c) a fixer supply structure defining a plurality of volumes each for containing a premeasured quantity of a different film fixer constituent, the constituents to be mixed to provide a film fixer solution;   (d) each of the supply structures being positionable selectively in at least one predetermined dispensing orientation with respect to the mixing structure;   (e) developer enabling means forming a part of the apparatus and including portions forming parts of the chemical mixing and developer supply structures, the developer enabling means enabling the dispensing of developer constituents only when the developer structure is in at least one predetermined dispensing orientation;   (f) fixer enabling means forming a part of the apparatus and including portions forming parts of the chemical mixing and fixer supply structures, the fixer enabling means enabling the dispensing of fixer constituents only when the fixer structure is in at least one predetermined dispensing orientation; and   (g) dispensing means carried by at least one of the structures and adapted to dispense developer and fixed constitutents from the developer and fixer structures into the respective developer and fixer mixing chambers when, but only when, enabled by the appropriate one of the enabling means, whereby to prevent the dispensing of fixer constituents into the developer mixing chamber and developer constitutents into the fixer mixing chamber.   
     
     
         4. Film processing chemical mixing apparatus comprising: (a) a chemical mixing assembly including structure defining developer and fixer mixing chambers into which constituents of developer and fixer are mixed, respectively;   (b) a developer supply structure defining a plurality of volumes each for containing a premeasured quantity of a different film developer constituent, the constituents to be mixed in the developer mixing chamber to provide a film developer solution;   (c) a fixer supply structure defining a plurality of volumes each for containing a premeasured quantity of a different film fixer constituent, the constituents to be mixed in the fixer mixing chamber to provide a film fixer solution;   (d) each of the supply structures being positionable selectively in at least one predetermined dispensing orientation with respect to the mixing structure;   (e) fixer and developer constituent dispensing means forming a part of the apparatus and adapted to dispense developer and fixer constituents from the developer and fixer structures into the respective developer and fixer mixing chambers;   (f) a dispensing means actuation mechanism connected to the dispensing means for actuating the dispensing means whenever the dispensing of constituents is desired;   (g) coupling mechanism connected to at least one selected structure for connection of the selected structure to a water supply for supplying water for mixture with the constituents;   (h) means forming a part of the apparatus and adapted to cause constituents and water dispensed into the mixing chambers to be mixed to provide predetermined quantities of mixed fixer and developer solutions for delivery to a film processor; and   (i) a delivery mechanism connected to the chemical mixing apparatus for   
     
     
        delivery of mixed film processing chemicals. 35. Film processing chemical mixing apparatus comprising: (a) a chemical mixing structure defining developer and fixer mixing chambers;   (b) the mixture structure including portions defining a space for support of a developer supply structure of a type defining a plurality of volumes each for containing a premeasured quantity of a different film developer constituent;   (c) the mixture structure including portions defining a space for support of a fixer supply structure of a type defining a plurality of volumes each for containing a premeasured quantity of a different film fixer constituent;   (d) condition-sensing means for sensing at least one chemical volume condition and emitting a constituent delivery signal; and   (e) dispensing means carried by at least one of the structures and connected to the condition-sensing means, the dispensing means being adapted to dispense developer and fixer constituents from the developer and fixer structures into the respective developer and fixer mixing chambers when, but only when, enabled by a constituent delivery signal.   
     
     
            The apparatus of claim 35 wherein the condition sensed is the volume 
     
     
        of fluid in one of the fluid mixing chambers. 37. The apparatus of claim 35 wherein the condition sensed is the presence of a supply structure. 
     
     
            A method of dispensing film processing chemicals, comprising the steps of: (a) providing a chemical mixing structure defining developer and fixer mixing chambers;   (b) providing a developer supply structure of a type defining a plurality of volumes each for containing a premeasured quantity of a different film developer constituent;   (c) providing a fixer supply structure of a type defining a plurality of volumes each for containing a premeasured quantity of a different film fixer constituent;   (d) providing a dispensing means carried by at least one of the structures and adapted to dispense developer and fixer constituents from the developer and fixer structures into the respective developer and fixer mixing chambers;   (e) sensing at least one chemical volume condition; and   (f) emitting a constituent delivery signal to the dispensing means in response to the sensed condition to permit the developer and fixer   
     
     
        constituents to be dispensed. 39. The method of claim 38, comprising the step of sensing the volume of fluid in any one of the fluid mixing 
     
     
        chambers. 40. The method of claim 38, comprising the steps of sensing the 
     
     
        presence of a supply structure. 41. A fluid mixing system, comprising: (a) a reservoir;   (b) a plurality of vessels comprising a first fluid supply, each vessel containing fluid and adapted to release the contained fluid into the reservoir;   (c) a piercer assembly disposed intermediate the first fluid supply and the reservoir, the piercer assembly for piercing each vessel to release the fluid contained therein into the reservoir;   (d) a second fluid supply in communication with the reservoir and the piercer assembly, the flow of the second fluid controlling operation of the piercer assembly; and   (e) a valve disposed intermediate the second fluid supply and the reservoir   
     
     
        to control the flow of the second fluid. 42. The fluid mixing system of claim 41 wherein the piercer assembly includes means for rinsing portions 
     
     
        of the fluid mixing system with the second fluid. 43. A mixing system for producing a developer solution and fixer solution used in the processing of exposed X-ray film and having a developer mixing unit for mixing a developer chemical with water and a fixer mixing unit for mixing a fixer chemical with water, each mixing unit comprising: (a) a reservoir;   (b) a supply means including a vessel for storing a predetermined amount of chemical and for providing the chemical to the reservoir;   (c) water input means for directing water under pressure to the reservoir and including control apparatus for controlling the flow of the water;   (d) a chemical release structure for releasing the chemical from the supply means into the reservoir and for directing the water into the reservoir, the release structure being actuated by the flow of water; and   (e) the control apparatus including a sensing means for engaging the supply means to sense the presence or absence of a chemical-containing vessel.   
     
     
            The mixing system of claim 43 wherein the supply means includes a plurality of vessels, and the chemical release structure engages the 
     
     
        vessels to release the chemicals. 45. The mixing system of claim 44 wherein the supply means additionally includes a portable container within which the vessels are disposed, the container including a plurality of openings disposed adjacent the vessels through which chemical flows to the 
     
     
        reservoir, the container also engaging the sensing means. 46. A fluid mixing system for mixing first and second fluids in a reservoir, the system having a supply structure including a vessel in fluid communication with the reservoir for supplying the first fluid to the reservoir, the system comprising: (a) a displaceable fluid release assembly disposed within the reservoir and including a tubular member, the tubular member having a pointed end portion for piercing the vessel and releasing the first fluid, the end portion including a tip, a slicing edge portion, and a fold-over edge portion;   (b) the tip and slicing portions providing cutting edges to sever a portion of the vessel to form a discharge opening, the fold-over portion providing inefficient slicing to fold the severed portion to permit the severed portion to remain connected to the vessel by a link; and   (c) the fluid release assembly being connected to a pressurized supply of the second fluid and being advanced when in use in response to flow of the   
     
     
        second fluid as the second fluid is introduced into the reservoir. 47. A fluid mixing system for mixing first and second fluids in a reservoir, the system having a supply structure including a vessel in fluid communication with the reservoir for supplying the first fluid to the reservoir, the system comprising: (a) a displaceable fluid release assembly disposed within the reservoir and including a tubular member, the tubular member having a pointed end portion for piercing the vessel and releasing the first fluid, the end portion including a tip, a slicing edge portion, and a fold-over edge portion;   (b) the tip and slicing portions providing cutting edges to sever a portion of the vessel to form a discharge opening, the fold-over portion providing inefficient slicing to fold the severed portion to permit the severed portion to remain connected to the vessel by a link; and   (c) the release assembly including: (i) a tubular member-supporting assembly connected at one end to a piston; and   (ii) a cylinder within which the piston reciprocates, the cylinder being in fluid communication with the second fluid and the piston being displaceable in response to the introduction of the second fluid into the     
     
     
        cylinder. 48. A chemical replenisher system for an X-ray film processor for mixing a selected one of developer or fixer chemical with water to produce a solution to be dispensed to an X-ray film processor, comprising: (a) a tank structure;   (b) chemical supply means associated with the tank structure for providing a predetermined quantity of prepackaged chemical;   (c) water input means connected to the tank structure for coupling water under pressure to the tank structure;   (d) a chemical release structure associated with the supply means to release the chemical to the tank structure;   (e) a control apparatus to control the operation of the chemical release structure, the control apparatus including an interlock mechanism actuated upon the presence of the proper supply means, the interlock mechanism being actuated only when the proper supply means is associated with the tank structure and the supply means contains an unused supply of chemical.   
     
     
        9. The replenisher system of claim 48, wherein the control apparatus further includes an indicator mechanism disposed within the tank structure and connected to the control apparatus for indicating the volume of solution in the tank structure, the water input means being actuated only when the interlock mechanism associated with the tank structure has been actuated and the indicator mechanism indicates that the volume of solution 
     
     
        in the tank structure has decreased to a predetermined level. 50. The replenisher system of claim 48 wherein the tank structure includes a support surface which engages the supply means and the interlock mechanism 
     
     
        includes an actuating member which is engaged by the supply means. 51. A mixing system for mixing film processing chemicals with water to produce a mixed solution, comprising: (a) a chemical supply means defining a plurality of volumes each containing a predetermined quantity of chemical to be supplied;   (b) the supply means including a plurality of frangible diaphragms each at the bottom of a different volume when the chemical supply means is in use; and   (c) mixing means coupled to the chemical supply means for mixing the chemicals with water to produce the mixed solution, the mixing means including: (i) a reservoir for storing the mixed solution;   (ii) water supply means for directing the water under pressure to the reservoir;   (iii) a release assembly for releasing the chemicals into the reservoir; and   (iv) support structure for supporting the chemical supply means, the support structure including a surface having openings through which the release assembly operates to break the diaphragms and through which the     
     
     
        chemicals are supplied to the reservoir. 52. A mixing system for mixing photographic chemicals and water in a reservoir, the system having a supply structure including a plurality of vessels for supplying the chemicals to the reservoir, and a fluid release assembly disposed within the reservoir comprising: (a) a plurality of hollow tubular members including portions adapted to engage and pierce the supply structure to release the chemicals;   (b) a cylinder; and   (c) a piston disposed within the cylinder and connected to the hollow members, the piston being acted upon by .Iadd.the .Iaddend.water under pressure to advance the hollow members into engagement with the supply   
     
     
        structure. 53. The fluid mixing system of claim 52, wherein a water supply is connected to the cylinder and wherein a selected one of the water supply or the cylinder includes an exit port to permit a portion of the 
     
     
        water to flow into the reservoir to agitate fluids in the reservoir. 54. The fluid mixing system of claim 52, further including a rinse mechanism coupled to the release assembly and disposed adjacent the supply structure, wherein a water supply is connected to the cylinder and wherein a selected one of the water supply or the cylinder includes a bypass to 
     
     
        permit a portion of the water to flow to the rinse mechanism. 55. Film processing chemical mixing apparatus comprising: (a) a chemical mixing structure defining a mixing chamber;   (b) a chemical supply structure defining a plurality of volumes each for containing a premeasured quantity of a different processing chemical constituent, the constituents to be mixed to provide a processing solution;   (c) the supply structure being positionable selectively in at least one predetermined dispensing orientation with respect to the mixing structure;   (d) enabling means forming a part of the apparatus and including portions forming parts of the chemical mixing and chemical supply structure, the enabling means enabling the dispensing of chemical constituents only when the supply structure is in at least one predetermined dispensing orientation; and   (c) dispensing means carried by at least one of the structures and adapted to dispense constituents from the supply structure into the mixing chamber when, but only when, enabled by the enabling means, whereby to prevent the dispensing of the wrong chemical constituents into the mixing chamber.   
     
     
            Film processing chemical mixing apparatus comprising: (a) a chemical mixing assembly including developer and fixer mixing chambers into which constituents of developer and fixer are mixed, respectively;   (b) a developer supply structure including a plurality of bottles each for containing a premeasured quantity of a different film developer constituent, the constituents to be mixed in the developer mixing chamber to provide a film developer solution;   (c) a fixer supply structure including a plurality of bottles each for containing a premeasured quantity of a different film fixer constituent, the constituents to be mixed in the fixer mixing chamber to provide a film fixer solution;   (d) each of the supply structures being positionable selectively in a predetermined dispensing orientation with the bottles inverted over the mixing chambers;   (e) fixer and developer constituent dispensing means forming a part of the apparatus and adapted to puncture bottle closing diaphragms to dispense developer and fixer constituents from the developer and fixer supply structures into the respective developer and fixer mixing chambers;   (f) a dispensing means actuation mechanism connected to the dispensing means for actuating the dispensing means whenever the dispensing of constituents is desired;   (g) coupling mechanism for connecting the mixing assembly to a water supply for supplying water for mixture with the constituents;   (h) means forming a part of the apparatus and adapted to cause constituents and water dispensed into the mixing chambers to be mixed to provide predetermined quantities of mixed fixer and developer solutions for delivery to a film processor; and   (i) a delivery mechanism connected to the chemical mixing apparatus for   
     
     
        delivery of mixed film processing chemicals. 57. In a fluid mixing system for mixing first and second fluids in a tank structure, the system having a supply structure operably associated with the tank structure for supplying the first fluid, the improvement comprising an advanceable fluid release assembly mounted within the tank structure and having one or more hollow members engaging the supply structure for releasing the first fluid, the release assembly having: (a) a cylinder having walls which define a bore;   (b) a piston within the bore and being operable by the second fluid for advancing the members into engagement with the supply structure; wherein   (c) the cylinder defining the bore has a first portion with relatively small cross-sectional dimension toward one end and a second portion with a relatively larger cross-sectional portion having at least one exit port in its walls to thereby provide passage of the second fluid through the cylinder into the tank structure.