Abstract:
A fill block for injection of fluid through a hinged lid is improved by making the fluid pathway therethrough of a constant cross-sectional area, and by providing one or more rounded surfaces to reduce or eliminate impact and contact with surrounding structures when the lid is open and closed. Using a more durable and flexible material for the fill block and insert sheet increases the lifetime of both components and reduces or eliminates the tendency of these components to stress crack. Polycarbonate is one example of such durable and flexible material.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. provisional application No. 60/559,470 filed Apr. 5, 2004. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to methods and apparatus for allowing air to escape from a chamber having a hinged lid and allowing liquids introduced to the chamber to flow to a float switch indicating a full chamber, and more particularly relates, in one embodiment, to methods and apparatus for allowing air and liquids flow to and from a chamber having a hinged lid, where the flow of air and liquids is through the lid near the hinge.  
       BACKGROUND OF THE INVENTION  
       [0003]     Apparatus are known for having hinged lids that open to permit access to a chamber in the apparatus behind the lid. One example of such an apparatus is a sterilizing system where various objects such as immersible surgical and diagnostic devices, e.g. medical scopes and instruments are inserted to sterilize them. Generally, the lid is opened to insert the instrument and the lid is closed. One or more fluids may be injected, and the system may be under pressure during the sterilization. In some systems, fluid is allowed to escape from the sterilization chamber through an orifice in the hinged lid.  
         [0004]     In some sterilizer system designs, there are blocks and structures with orifices and pathways therein near the hinge of the lid to channel the fluids from the chamber covered or sealed by the lid out of the system. Experience has shown that frequent and constant opening and closing of the lid not only stresses and damages these blocks and conduits, but has the potential of damaging the chamber interior, processing tray and/or structures of the system near the hinge. One structure that&#39;s often stressed to the cracking or breaking point is a polymer plastic insert sheet in the hinged lids of these systems. Some of these sterilizer systems have an inflatable seal that pushes the instrument tray into the insert at a great force. At other times, the operator may slam the lid which forces or hits the insert sheet into the contents of the chamber at more than the recommended and usual impact. Additionally, if an operator is not careful, the scopes and other instruments placed in the chamber for sterilizing may not be properly aligned or oriented and may extend into the space that the insert sheet normally occupies at the time the lid is closed resulting in damage both to the insert sheet and the instruments.  
         [0005]     It would be desirable if the blocks and structures containing the pathways for injecting fluids through a hinged lid inhibited or prevented damage through repeated use and were more durable. Similarly, it would be useful if the insert sheet was more durable and flexible.  
       SUMMARY OF THE INVENTION  
       [0006]     Accordingly, it is an object of the present invention to provide a hinged lid assembly having greater durability.  
         [0007]     It is another object of the present invention to provide a fill block connected to a hinged lid that is more efficient at permitting fluid to escape and flow through a system covered by the lid and that did not cause damage to surrounding structures that it touches or is in proximity to during opening and closing.  
         [0008]     Another object of the invention is to provide a lid assembly that is more durable and less subject to damage or breaking.  
         [0009]     In carrying out these and other objects of the invention, there is provided, in one form, a fill block for transport of fluid through a hinged lid. The fill block has a block body; a substantially flat contact face adapted to connect with an insert sheet; a fluid pathway having a first aperture on the flat contact face and a second aperture on a different portion of the block body than the flat contact face. The fill block also has at least one rounded surface to minimize impact with a structure when the insert sheet is closed or opened, where the insert sheet is connected to, integral with or the same thing as the hinged lid.  
         [0010]     In another non-limiting embodiment of the invention, there is provided an assembly to permit transport of fluid through a hinged lid near a hinged edge that includes an insert sheet, where the insert sheet is connected to, integral with or the same thing as the hinged lid. The insert sheet includes a hinged insert edge along one side of the insert sheet, where the hinged edge is connected to, integral with or the same thing as a hinged insert edge of the hinged lid. The insert sheet also has at least one hinge on the hinged insert edge, where the hinge has an axis parallel to the hinged insert edge. The insert sheet also has an opening near the hinged insert edge. The fill block includes a block body; a substantially flat contact face adapted to connect with the insert sheet; a fluid pathway having a first aperture on the flat contact face and a second aperture on a different portion of the block body than the flat contact face. The first aperture of the fill block mates with, and is ultimately affixed around the opening of the insert sheet. The fill block also has at least one rounded surface to minimize impact with a structure when the lid is closed or opened, and alternatively when a seal inside the insert pushes a chamber processing tray up against the lid. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a schematic, three-quarters, perspective view of a sterilizing system with the hinged lid in open position showing one possible context of the invention;  
         [0012]      FIG. 2  is an exploded, three-quarters, perspective view of one embodiment of the fill block of this invention and how it fits to an insert sheet and a backing plate;  
         [0013]      FIG. 3A  is an injection end view of one embodiment of the fill block of this invention;  
         [0014]      FIG. 3B  is a back view of the embodiment of the fill block of this invention shown in  FIG. 3A ;  
         [0015]      FIG. 3C  is a curved end view of the embodiment of the fill block of this invention shown in  FIG. 3A ;  
         [0016]      FIG. 3D  is a side view of the embodiment of the fill block of this invention shown in  FIG. 3A ;  
         [0017]      FIG. 3E  is a front view of the embodiment of the fill block of this invention shown in  FIG. 3A ; and  
         [0018]      FIG. 3F  is an end view of an alternate, prior art fill block showing a beveled edge. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     Shown in  FIG. 1  is one non-limiting embodiment of a sterilizing system or device  10  having a hinged lid  12  and an interior chamber  14 . The interior chamber  14  may include, but is not necessarily limited to, a processing tray  16  shown in this particular embodiment, but also a structure integral with device  10 , a gasket, a spacer, a cover, a handle, a frame, and other like structures.  
         [0020]     In the particular embodiment shown in  FIG. 1 , the hinged lid  12  is in the open position bearing on hinges  18 . The number of hinges  18  is not important so far as hinged lid  12  pivots or swings on at least one hinge  18 . Lid  12  has an insert sheet  20  within it. Insert sheet  20  may be connected to, integral with or the same thing as hinged lid  12  in various non-limiting embodiments. Insert sheet  20  may be transparent and lid  12  may have a window  22  therein to permit viewing of anything within chamber  14 , as in the  FIG. 1  embodiment. Lid  12  may also have a gasket  24  for forming a seal with the chamber  14  or other interior of system or device  10 , such as in an embodiment where the chamber is under pressure. The gasket  24  may be glued to the insert and may be made of EPDM (ethylene-propylene diene monomer) or silicone rubber or other suitable material. In one non-limiting embodiment, the lid  12  may be metal, and in one non-restrictive alternative may be aluminum, stainless steel, or other suitable metal. In one non-limiting embodiment, the hinge  18  is connected to the metal part of the lid  12 , and hinge  18  is not connected to the insert  20 . However, in other embodiments lid  12  and insert  20  may be one or otherwise integral with each other.  
         [0021]     The insert sheet  20  of lid  12  has a insert edge  26  adjacent to, connected to, integral with or the same thing as a hinged edge  28  of lid  12 . Insert edge  26  is provided with an opening  30  to permit fluids and air to be passed or drained from chamber  14  through lid  12  or alternatively injected, introduced or placed into chamber  14  through opening  30  in lid  12 . In another non-limiting embodiment, air relief is the only fluid entering or leaving opening  30 . Vacuum relief may be defined herein as the chamber  14  draining out water or other fluids through a port (not shown) in the chamber  14  bottom.  
         [0022]     In one non-limiting embodiment of the invention, and simply to give a sense of scale, the system or device  10  seen in  FIG. 1  may have a width of about 32 inches, a depth of about 24 inches, a height of about 13 inches, and a weight of about 150 pounds.  
         [0023]     Shown in  FIG. 2  is a detailed, exploded, three-quarters, perspective view of one embodiment of the fill block  40  of this invention and how it fits to an insert sheet  20  and a backing plate  50 . As compared with  FIG. 1 , the insert sheet  20  in  FIG. 2  is upside-down and viewed from the other side. Opening  30  is shown in insert sheet  20  where the fluid and air would flow from the chamber  14  (not shown) in a direction out from the Figure toward the viewer. In contrast, in  FIG. 1 , the fluid would go through opening  30  into the Figure, away from the viewer. It will be appreciated that the direction of flow shown in  FIG. 2  (dark arrows) is consistent with an embodiment where chamber  14  is filled with a fluid (liquid or air) from another source or opening not shown and drained through opening  30 . In an alternate version of the invention, chamber  14  would be filled by a fluid from hose  58  flowing opposite or against the dark arrows and the chamber  14  would be drained by a different port (not shown).  
         [0024]     In one non-restrictive embodiment, liquid flow from hose  58  (in the direction of the dark arrows of  FIG. 2 ) would go to a float switch or other valve or detector (not shown) to indicate that chamber  14  was full and to shut off liquid flow thereto. As part of a sterilizing cycle, in one embodiment of the invention, air (generally speaking, a fluid) would flow back through into the chamber  14  in the reverse direction from that indicated by the dark arrows in  FIG. 2 .  
         [0025]     In one non-limiting embodiment of the invention, fill block  40 , insert sheet  20 , and backing plate  50  would be transparent, and indeed, this would be a commercial embodiment of the invention, as shown. However, it may be understood that one or more of the elements being discussed or elements of the invention may be opaque or translucent, rather than transparent, and the invention should not be limited by any of these optical properties.  
         [0026]      FIG. 2  shows fill block  40  in detail, including the block body and a substantially flat contact face  32  adapted to connect to, mate with or be adhered to insert sheet  20 , in this embodiment specifically by extension or tab  34  which includes opening  54  that mates with first aperture  36  on the contact face  32  of fill block  40 . By “substantially flat” is meant of sufficient planarity to fit flush to another similar substantially flat surface, such as insert  20 , and to be affixed, adhered or glued thereto. Fill block  40  also has a fluid pathway  38  extending from a second aperture  42  through block  40  to first aperture  36 . In the particular embodiment shown in  FIG. 2 , the fluid pathway  38  has a main axis  44 , where the main axis is perpendicular to first aperture  36 , and the main axis  44  is oriented parallel to the axes of the hinges  18  that open and close insert sheet  20  and hinged lid  12 , shown more particularly in  FIG. 1 . This orientation places second aperture  42  at a right angle or 90° to first aperture  36 . While this orientation is not necessarily required, it is expected that it may find advantages in this invention, such as being more readily consistent and/or congruent with the operation of opening and closing of hinged insert sheet  20 .  
         [0027]     It will be appreciated that embodiments of the invention can be envisioned where insert sheet  20  does not have an extension or tab  34 , but where fill block  40  fits flush with a straight or linear insert edge  26 .  
         [0028]     In one non-limiting embodiment of the invention, fluid pathway  38  has a uniform cross-section. However, fluid pathway  38  does not necessarily have to have the same shape to have the same cross-sectional area in this embodiment. A fluid pathway  38  having a uniform cross-section does not block, impede or inhibit fluid flow, and thus does not inhibit fluid flow due to such obstruction, narrowing or blocking, which may be undesirable in some cases. In another non-limiting embodiment of the invention, the opening  54  in the insert sheet  20  is at least as large as the cross-sectional area of fluid pathway  38  for the same reason. In one non-restrictive version of the invention, and to give a sense of scale in one embodiment of the invention, this uniform cross-sectional area would be about the area of a circular opening ⅜-inch (about 1 cm) in diameter or about 0.1 in 2  (0.7 cm 2 ).  
         [0029]     Fill block  40  also has at least one rounded surface to minimize impact with a structure when the insert sheet  20  is open or closed. This structure is typically device  10  itself, a processing tray  16 , a gasket, a spacer, a cover, a handle, a frame or some other structure in proximity to block  40  when it is open or closed. With reference to  FIGS. 3A-3E , typically, conventional fill blocks have sharp corners or edges  46  as shown in phantom lines in all  FIGS. 3A through 3E . Shown in  FIG. 3F  is an alternate, prior fill block  40 ′ where sharp edge  46  is replaced by beveled edge  62 . The designers of this prior fill block realized the difficulties caused by sharp edge  46 , and beveled the edge to an angle x of about 120°. However, even this beveling did not sufficiently minimize impact with a structure as described above, and cracks  60  such as shown in  FIG. 1  would still result.  
         [0030]     In one non-limiting embodiment of the invention, a first curved or rounded surface is surface or rounded edge  48 , which is a rounded surface generally parallel to the axes of hinges  18  to avoid or limit contact with other structures as insert sheet  20  is open and closed. Curved edge  48  is curved in the direction of arrow  49  in  FIG. 2  and edge  48  extends along the back side of block  40  as seen in  FIG. 2 .  
         [0031]     Another rounded surface is rounded corner  52 , which also serves the function of limiting or preventing contact with other structures during the opening and closing of insert sheet  20 . Rounded corner  52  is curved in the direction of arrow  53  as seen on the left side of block  40  seen in  FIG. 2 . To give some sense of scale, in one non-limiting embodiment of the invention fill block  40  may be about 2.5 inches long, not including the nozzle second aperture  42  shown (which may optionally be a separate piece), about 1 inch tall across the flat contact face, and about 0.8 inch wide across the top at its widest point.  
         [0032]     With further reference to  FIG. 2 , it may be seen that fill block  40  is designed to connect to or mate with insert sheet  20  so that first aperture  36  on block  40  mates with opening  54 , in this embodiment on extension or tab  34 . Tab  34  may be provided with at least one passageway  56  from opening  54  to opening  30  to provide fluid communication therewith. In the particular embodiment shown in  FIG. 2 , two passageways  56  of generally flat, rectilinear, planar shape are formed, where one major wall thereof is provided by backing plate  50 . In one non-limiting embodiment of the invention, the total cross-sectional area of passageways  56  and of opening  30  are the same as that of fluid pathway  38 , again to avoid inhibiting or blocking fluid flow. Block  40 , insert sheet  20  and backing plate  50  may be made of plastics or polymers as will be further described below, and may be adhered, glued, connected and/or assembled as shown in  FIG. 2 .  FIG. 2  also shows flexible hose  58  that may be removably attached to second aperture  42  on fill block  40 .  
         [0033]     Thus, the fluid pathway to drain or exit fluid from chamber  14  of device or system  20  (shown in  FIG. 1 , but not  FIG. 2 ) is as shown by the dark arrows in  FIG. 2 , generally out opening  30  in chamber  14  and via passageways  56  of sheet  20  through opening  54  of insert sheet  20  and first aperture  36  of fill block  40  through fluid pathway  38 , second aperture  42 , and out hose  58 . As mentioned, the invention is not restricted by the flow direction of the particular embodiment of a system  20 .  
         [0034]     Commercial lids, fill blocks and backing plates are made of PLEXIGLASS acrylic polymers. In a hospital environment, sterilization systems used for the terminal sterilization of surgical scopes and instruments operate at temperatures of from about 35 to 40° C. minimum up to about 50 to 55° C. maximum or more over a cycle time of about 30 to 45 minutes. The water pressure entering such systems is often controlled at about 40 to about 50 psig. During a sterilization cycle, a flow of about 4 gallons per minute (gpm) may enter the system at an approximate pressure of about 40 psig.  
         [0035]     A sterilization cycle is initiated when the lid is closed. Typically, secure lid closure is monitored throughout the cycle. An air compressor is enabled and controlled by pressure switches pressurizing an inflatable seal or gasket (such as  24 , although such seal or gasket could be alternatively or additionally in the base of the unit or system as well), which locks the lid closed and seals the processing or sterilizing chamber. In an alternate embodiment, the seal is not inflatable. The switch maintains the air manifold at 35 to 45 psig, in one non-limiting embodiment, turning the compressor on and off as necessary.  
         [0036]     A function of some of these sterilizing systems is to allow a processing tray—such as a removable tray used to route a sterilant or biocidal agent (e.g. peracetic acid, hydrogen peroxide or other peroxide, and the like) in and around a surgical scope, instruments, or the like—to be pushed up against the lid gasket in order to seal the chamber. This may be accomplished by the inflatable seal pushing the tray upward when inflated in another non-limiting embodiment.  
         [0037]     It may thus be readily seen that the materials of the fill block, insert sheet and backing plate are subjected to a variety of severe conditions including, but not necessarily limited to, elevated temperatures, elevated pressures, a sterilizing and/or cleansing environment and chemicals (e.g. peracetic acid, peroxyacetic acid, hydrogen peroxide, and the like), as well as mechanical stresses due to repeated and frequent opening of the lid and assembly that cause the various parts and elements of the assembly to hit and impact one another, in addition to aging. It has been found that acrylic polymers over time and the conditions mentioned may form cracks  60  in the locations shown on insert sheet  12  in  FIG. 1  as well as other locations. Stresses on insert sheet  12  also occur because of impact with or contact with an inflatable seal in the body of the sterilizing system  10 , and by the insert sheet  12  being slammed closed with too much force, and/or by impact with a scope or other instrument that is not properly placed in processing tray  16  and extending outward into space normally occupied by insert sheet  12 .  
         [0038]     It has been further discovered that fill block  40 , as well as insert sheet  20  and/or backing plate  50  are advantageously made of polycarbonate polymers and copolymers. Polycarbonates have the additional advantages of being transparent, and readily assembled using industrial and engineering adhesives or welded using a solvent methyl chloride, methylene chloride, and the like. In one non-limiting embodiment, a suitable adhesive is E6000 adhesive. Other polymers may be used in accordance with the method of this invention as long as they meet the requirements and fulfill the purposes and goals outlined herein. Thus, one advantage of the invention is the implementing of more durable and stress resistant polycarbonate or other material instead of less flexible and durable acrylic polymers which have a tendency to crack under normal operating procedures. Polycarbonates have a number of advantages including, but not necessarily limited to, being shatter-resistant, being harder than acrylic polymers, and being able to withstand temperatures of at least 250° F. Polycarbonates are of the group of thermoset polymers which does not melt or reflow and cannot be remolded; polycarbonates are used where strength and heat resistance is required. Polycarbonate insert sheets are also more flexible than acrylic polymers when the lid  12  is closed and chamber  14  is placed under pressure and thus further resist cracking.  
         [0039]     In another non-restrictive embodiment of the invention, polycarbonate insert sheets  20  may be adhered to metal hinged lids  12 , such as those made of aluminum, e.g., by means of an adhesive. Suitable adhesives may include, but are not necessarily limited to, silicone RTV (room temperature vulcanizing) adhesives. A specific, non-restrictive example of a suitable silicone RTV adhesive is Dow Corning® 832 multi-surface adhesive sealant. In some cases, it may be necessary to improve the adhesion of insert  20  on an aluminum lid  12  by abrading or roughening the surface of the insert  20  and/or by using a primer. Suitable primers include, but are not necessarily limited to, mixtures of inorganic and organic compounds, in non-restrictive examples one or more of toluene, alkylene glycol alkyl ethers such as propylene glycol methyl ether, alkyl glycol acetates such as butyl glycol acetate, alkoxyalcohols such as 2-methoxypropanol, and silanes such as methoxysilane and/or aminoethylaminopropyltrimethoxysilane. In one non-limiting embodiment of the invention, a specific, suitable primer may be Dow Corning® 1205 prime coat.  
         [0040]     Thus, the fill block  40  of the present invention is of a better configuration and more suitably designed to cause less problems upon repeated movement of the lid  12 , and is of a more durable and sturdy material, as compared with prior structures.  
         [0041]     In the foregoing specification, the invention has been described with reference to specific embodiments thereof, and is expected to be effective in providing a structure and configuration that prolongs the life of the fill block and hinged lid. However, it will be evident that various modifications and changes can be made to the inventive apparatus without departing from the broader spirit or scope of the invention as set forth in the appended claims. Accordingly, the specification is to be regarded in an illustrative rather than a restrictive sense. For example, specific combinations of designs and materials falling within the claimed parameters, but not specifically identified or tried in a particular apparatus or device, or under specific conditions, are anticipated to be within the scope of this invention.