Abstract:
Disclosed is a closure for ducts or receptacles for pressurized fluids, including an annular supporting structure ( 10 ), which defines an opening ( 11 ) for accessing the duct or receptacle, and a hatch ( 30 ), connected in an articulated manner to the supporting structure ( 10 ), with the ability to move between a closed position and an open position, wherein the supporting structure ( 10 ) includes a sealing surface ( 13 ), characterized in that it includes a sealing element ( 20 ) that can be positioned in the opening ( 11 ), the sealing element ( 20 ) including an expansible portion ( 21 ) with an inner surface ( 24 ) facing the duct and an outer surface ( 23 ) facing the sealing surface ( 13 ), the expansible portion ( 21 ) being able to expand as a result of the pressure of the fluid that acts on the inner surface ( 24 ) so that the outer surface ( 24 ) is placed in contact with the sealing surface ( 13 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The invention concerns a closure for pressurized ducts or receptacles. In detail, the invention relates to a closure of the type adapted to allow access to the inside of said duct or receptacle. 
       BACKGROUND OF THE INVENTION 
       [0002]    Pressurized ducts of medium and large size, for example for transporting pressurized fluids such as fuels (liquid or gaseous) or the like, are generally provided with one or more branches through which it is possible to access the inside of the duct. These branches define accesses that allow apparatus to be inserted into the duct to perform inspections, cleaning and/or maintenance operations. 
         [0003]    Generally, these branches comprise a section of pipe, which connects on the lateral surface of the main duct, fitted on the free end of which is a closure that allows sealing of said section of pipe when the duct is filled with the pressurized fluid. 
         [0004]    Known closures generally comprise an annular element, fitted to the free end of the pipe, which define an opening through which the duct can be accessed. Said opening can be closed hermetically by means of a movable hatch connected in an articulated manner to said annular element. 
         [0005]    The seal of the closure is generally guaranteed by two abutment surfaces, obtained respectively on the hatch and on the annular element, between which a gasket is interposed. 
         [0006]    This gasket, made of a resilient material such as rubber or the like, is generally housed in a seat obtained on the hatch or, at times, on the annular element. 
         [0007]    Examples of closures for pressurized ducts thus structured are described in EP 1843065 B1, WO 02/097319 A1 and U.S. Pat. No. 7,341,161 B2. 
         [0008]    However, these known closures can only be fitted to ducts in which the pressure of the fluid does not exceed values of around 500 bar. 
         [0009]    In fact, above this threshold the pressurized fluid, which normally penetrates the gap between the two abutment surfaces, presses on the gasket, to such an extent as to deform it and thrust it toward the outside of the closure. 
         [0010]    In these conditions, the gasket is therefore unable to contain the fluid, which can escape from the closure. 
         [0011]    The higher the pressure of the fluid is, the more evident this phenomenon is. 
         [0012]    In this context, the object of the present invention is to provide a closure for pressurized ducts or receptacles that solves the problems of the prior art described above. 
         [0013]    It is therefore an object of the present invention to provide a closure that can guarantee seal even at pressures of the fluid greater than 1000 bar, for example up to 2000 bar. 
         [0014]    Another object of the present invention is to provide a closure that is reliable and with parts that are not subject to wear and, therefore, which do not require frequent periodic maintenance. 
         [0015]    A further object of the present invention is to provide a closure that is practical and easy to handle. 
         [0016]    In addition to the above, an object of the present invention is also to provide a closure that is simple and inexpensive to produce. 
         [0017]    These objects are achieved by a closure for ducts or receptacles for pressurized fluids, which comprises:
       a supporting structure, to be fitted to a free end of a section of a tubular element, which defines an opening for accessing the duct or receptacle, and,   a hatch, connected in an articulated manner to said supporting structure, with the ability to move between a closed position and an open position.       
 
         [0020]    The closure according to the invention can be fitted to ducts or receptacles intended to transport or contain pressurized fluids, such as fuels (liquid or gaseous), water or the like. 
         [0021]    More in general, the closure of the invention can therefore be fitted to hollow bodies intended to contain a pressurized fluid, either static or moving. 
         [0022]    Therefore, in the description below, the term “duct” or “pressurized duct” relates to a generic hollow body among those mentioned above. 
         [0023]    At the opening thereof, the supporting structure is provided with an annular sealing surface that extends from the opening toward the tubular element, along a direction X. 
         [0024]    The closure according to the invention comprises a sealing element that, when the closure is closed, is arranged in the opening. 
         [0025]    Said sealing element comprises an expansible portion with an inner surface, which faces the duct, and an outer surface, facing the sealing surface of the supporting structure. 
       SUMMARY OF THE INVENTION 
       [0026]    According to the invention, the expansible portion is configured so as to be able to deform as a result of the pressure of the fluid that acts on its inner surface so that the outer surface is thrust toward the sealing surface of the supporting structure. 
         [0027]    Preferably, the expansible portion has a shape and a size substantially complementary to that of the sealing surface. More in detail, the expansible portion has a size that, when the sealing element is positioned in the opening and no pressurized fluid is present in the duct, the outer surface detaches from the sealing surface. 
         [0028]    Preferably, the distance between said surfaces is a few hundredths or tenths of millimeter. 
         [0029]    As a result of this, the sealing element can be positioned in the opening, or removed therefrom, without effort, when the hatch is open and said opening is accessible. 
         [0030]    Instead, when pressurized fluid is present in the duct, the expansible portion expands until its outer face comes into contact with the sealing surface. Therefore, a contact area that prevents the fluid from passing toward the outside is created between the two surfaces. 
         [0031]    According to a preferred aspect, the expansible portion comprises an annular wall on which the inner surface and the outer surface are obtained. 
         [0032]    The thickness of the expansible portion, or more precisely of the annular wall, is preferably more or less constant. 
         [0033]    In this way, when subjected to the pressure of the fluid, the expansible portion can expand in a substantially uniform manner in its direction of extension. 
         [0034]    The contact pressure generated between the outer surface and the sealing surface is therefore more or less constant. 
         [0035]    To guarantee a better seal of the closure, the sealing element can comprise a gasket that surrounds the expansible portion. Preferably, the gasket is housed in an annular seat obtained on the outer surface of the expansible portion. 
         [0036]    Advantageously, the contact between the outer surface of the expansible portion and the sealing surface prevents the gasket from deforming or leaving its seat, as occurs in prior art closures. 
         [0037]    According to another aspect of the invention, the sealing surface and the outer surface of the expansible portion have a cylindrical shape. 
         [0038]    This shape makes it more practical and less costly to machine the sealing surface and the outer surface to obtain the aforesaid difference in size. 
         [0039]    Alternatively, these surfaces can have a conical or truncated-cone shape. In this case, said surfaces are arranged so that their diameter decreases from the opening toward the duct, to facilitate positioning of the sealing element in the opening. 
         [0040]    In another aspect of the invention, at least the expansible portion of the sealing element is made of metal. This material allows the sealing element to withstand very high pressures, for example even greater than 1000 bar, which are exerted on the inner surfaces exposed to the fluid. 
         [0041]    Moreover, the sealing element produced in this way is subject to very limited wear, so that maintenance or replacement operations are not necessary, even after numerous opening and closing cycles of the hatch or after several years of use of the closure. 
         [0042]    According to a variant of the invention, the sealing element can be separable from the hatch. 
         [0043]    In this variant, the sealing element preferably also comprises a front wall. In practice, said front wall is arranged so as to close one side of the expansible portion. 
         [0044]    When the hatch is in closed position, and the sealing element is positioned in the opening, said front wall is placed against an inner face of the hatch. 
         [0045]    According to another aspect of the invention, said front wall can be provided with connection means for the connection of gripping means that allow the expansible element to be positioned in the opening or removed therefrom. 
         [0046]    Said connection means, for example, can comprise a threaded hole into which a handgrip can be screwed. 
         [0047]    In this variant, the hatch is preferably connected to the supporting structure so as to rotate about an axis parallel to the direction of extension of the sealing surface. 
         [0048]    For example, the hatch can be pivoted on the supporting structure so that its inner face, during rotation, slides on a front abutment surface of the supporting structure. 
         [0049]    This hinge is particularly simple and inexpensive to produce and practical to implement. 
         [0050]    This configuration can be adopted as on said front abutment surface there are no gaskets or other sealing elements to guarantee sealing of the closure. 
         [0051]    According to an aspect of the invention, in this variant the hatch can be provided, on at least one part of its outer perimeter, with a projecting locking profile. The supporting structure, in turn, can be provided with a stop element with a seat adapted to house said locking profile, when the hatch is rotated in closed position. 
         [0052]    In another variant of the invention, the sealing element can instead be integral with the hatch. 
         [0053]    In practice, in this variant the expansible portion is connected to an inner face of the hatch so that, when the hatch is closed, said expansible portion is placed in the opening of the supporting structure at the sealing surface. 
         [0054]    The hatch, in this case, is preferably connected to the annular structure so as to be able to rotate about at least one axis perpendicular to the direction of extension of the sealing surface. 
         [0055]    In other words, the hatch is hinged, directly or indirectly, to the supporting structure in the manner of a leaf door. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0056]    Further characteristics and advantages of the present invention will become more apparent from the description of an example of a preferred embodiment of a closure for pressurized ducts, as illustrated in the accompanying figures, wherein: 
           [0057]      FIG. 1  is a perspective view of a closure according to the invention, in open position; 
           [0058]      FIG. 2  is a perspective view of the closure of  FIG. 1 , in the closing phase, with the sealing element positioned in the opening; 
           [0059]      FIG. 3  is a sectional side view of the closure of  FIG. 1 , in closed position. 
           [0060]      FIG. 4  is a front view of the closure of  FIG. 1 , in closed position; 
           [0061]      FIG. 5  is a perspective view of a closure according to another variant of the invention, in open position; 
           [0062]      FIG. 6  is a sectional side view of the closure of  FIG. 5 , in closed position; 
           [0063]      FIG. 7  is a front view of the closure of  FIG. 5 , in closed position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0064]    With reference to the accompanying  FIGS. 1 to 4 , the number  1  indicates as a whole a closure for ducts or receptacles for pressurized fluids, such as fuels, water or the like. 
         [0065]    The closure  1  comprises a substantially annular supporting structure  10 , which defines an opening  11  through which the inside of the pressurized duct can be accessed, directly or indirectly. 
         [0066]    Generally, this supporting structure  10  is fitted, at a rear edge  12 , to the end of a tubular element (not illustrated in the figure). 
         [0067]    As a function of the context of use, the tubular element can be part of the duct or of the receptacle or can be another element communication therewith. 
         [0068]    According to the invention, the seal of the closure  1  is guaranteed by a sealing element  20 , adapted to cooperate with a sealing surface  13  obtained on the supporting structure  10 . 
         [0069]    This sealing element  20  can therefore be positioned in the opening  11  when it is necessary to seal the closure and, on the contrary, can be removed when it is necessary to open the closure to access the duct. 
         [0070]    According to the invention, the sealing element  20  comprises an expansible portion  21  capable of expanding when subjected to the pressure of the fluid inside the duct. 
         [0071]    In a preferred variant, the expansible portion  21  comprises an annular wall  22 , with an outer surface  23  and an inner surface  24 . 
         [0072]    Preferably, the sealing element  20  also comprises a front wall  25  that closes, on one side, said annular wall  22 . 
         [0073]    Said front wall  25  has an outer face  29  on which a connection means is obtained. 
         [0074]    This means allows the connection of gripping means, such as a handgrip or the like, to position the sealing element  20  on, or remove it from, the opening  11 . 
         [0075]    In the variant illustrated, said connection means comprises a threaded hole  29   a.    
         [0076]    To facilitate correct positioning of the sealing element  20  in the opening, this is provided with an abutment  18  that delimits the extension of the sealing surface  13 . 
         [0077]    This abutment acts as a stop for the free edge  22   a  of the annular wall  22  when the sealing element  20  is slid into the opening  11 . 
         [0078]    When the sealing element  20  is placed in the opening  11 , the outer surface  23  of the expansible portion  21  is facing the sealing surface  13  of the supporting structure  10 . 
         [0079]    Said sealing surface  13  and said outer surface  23  preferably, but not exclusively, have a cylindrical shape. 
         [0080]    As already mentioned, the inner surface  24 , when the sealing element  20  is placed in the opening  11 , is instead facing the duct. 
         [0081]    Therefore, when the pressure in the duct reaches a given threshold, the expansible portion starts to expand radially until the outer surface  23  is in contact with the sealing surface  13 . 
         [0082]    For this purpose, the outer surface  23  of the expansible portion  21  has a shape substantially complementary to that of the sealing surface. 
         [0083]    To minimize the expansion required to bring the two surfaces into contact, the distance between them, when the duct is at ambient pressure, is preferably between 2 mm and 0.01 mm. 
         [0084]    For example, in the variant in which these surfaces have a cylindrical shape, the difference between their diameters is between 1 mm and 0.3 mm. 
         [0085]    This also allows at least the expansible portion  21 , or optionally the whole sealing element  20 , to be made of metal or other materials characterized by a high elastic modulus. 
         [0086]    The thickness of the annular wall  22 , for a section or for the whole of its extension, is more or less constant. In this way, the radial expansion of the expansible portion  21  is substantially homogeneous along its direction of extension and, consequently, the contact pressure between the outer surface  23  and the sealing surface  13  is more or less constant. 
         [0087]    In a preferred embodiment, the sealing element  20  is provided with a gasket  26  housed in a seat  27  obtained on the outer surface  23 . 
         [0088]    The gasket  26 , when the expansible portion  21  is positioned in the opening  11 , is pressed against the sealing surface  13  to increase the seal of the closure. 
         [0089]    Preferably, the gasket is positioned at the free edge  22   a  of the annular wall  22 . 
         [0090]    According to the invention, the closure is also provided with a hatch  30  adapted to maintain the sealing element  20  in position when the pressurized fluid is present in the duct. 
         [0091]    In fact, the pressure, acting also on the inner face  28  of the front wall  25 , thrusts the sealing element  20  outward. 
         [0092]    This thrust is typically greater than the friction force that is generated between the outer surface  23  and the sealing surface  13  and, therefore, without the hatch, it would push the sealing element  20  out of the opening  11 . 
         [0093]    More in detail, the hatch  30  is connected to the supporting structure  10  by means of a hinge that allows it to move from an open position, in which it is moved away from the opening  11 , and a closed position, in which is positioned in front of said opening. 
         [0094]    When the hatch  30  is in closed position, the outer face  29  of the front wall  25  is close to or in contact with an inner face  31  of said hatch  30 . 
         [0095]    In a preferred variant, the hatch  30  is pivoted on the supporting structure  10  so as to rotate about an axis R parallel to the direction of extension X of the sealing surface  13 . 
         [0096]    During rotation, this causes the inner face  31  of the hatch to slide in contact with, or against, a front abutment surface  14  of the supporting structure  10 . 
         [0097]    Said surfaces are therefore flat and preferably smooth. 
         [0098]    A handle  37 , connected to the hatch  30 , allows this latter to be gripped to rotate it from the closed position to the open position, and vice versa. 
         [0099]    According to the invention, the hatch  30  is also provided, on at least a part of its outer edge, with a locking profile  34  that projects from said edge. 
         [0100]    This profile, when the hatch is in closed position, can be inserted into a seat  16  of a stop element  15 . 
         [0101]    This stop element  15  constrains the hatch  30  to translate along the direction X, opposing the thrust that the sealing element  20  can exert on the hatch  30  when pressurized fluid is present in the duct. 
         [0102]    Another stop element  35  can be provided on the hatch  30  to engage, in a seat  36 , a locking profile  17  projecting from an edge section of the supporting structure  10 . 
         [0103]      FIGS. 5 to 7  illustrate another variant of the closure according to the invention. 
         [0104]    In this variant, the sealing element  20  is integral with the hatch  30 . The sealing element  20  is therefore moved together with the hatch  30  between the open position and closed position, in which is positioned in the opening  11 . 
         [0105]    More in detail, the annular wall  22  of the expansible portion  21  projects from the inner face  31  of the hatch  30 . Therefore, the annular wall  22  is closed on one side. 
         [0106]    The hatch  30  is connected to the supporting structure  10  so as to rotate about a first axis R 1  perpendicular to the axis X of extension of the sealing surface  13 . 
         [0107]    For example, the hatch  30  is connected to the structure  10  by means of a hinge  39  of the type used for a leaf door. 
         [0108]    Preferably, this hinge is provided with a second rotation axis R 2 , parallel to the first, which in the last section of the closing movement allows the hatch to translate along the direction X. 
         [0109]    In the example of the figures, the sealing surface  13  and the outer surface  24  of the expansible portion  21  have a cylindrical shape. 
         [0110]    In this variant, to facilitate insertion of the sealing element  20  into the opening  11 , said surface can have a truncated-cone shape, with a diameter that decreases from the opening  11  toward the rear edge  12  of the supporting structure  10 . 
         [0111]    In this variant, locking of the hatch  30  is implemented by means of a jaw element  19  that, in the closed position, can be clamped about a locking profile  38  that projects from the outer edge of the hatch  30 . 
         [0112]    The invention has been described for illustrative and non-limiting purposes according to some preferred embodiments thereof. Those skilled in the art may find numerous other embodiments and variants, all falling within the scope of protection of the claims below.