Abstract:
An improved bypass valve, suitable for the connection of terminal units in which a heat exchange occurs between the environment to be conditioned and a thermal-carrier fluid, in particular a liquid, with the lines of delivery or supply and return of the fluid, with these units typically defined by heat exchangers, fan coil units, batteries for air handling units of the AHU (air handling unit) type in the field of HVAC (heating, ventilation and air conditioning), including an H-shaped valve-body with two opposed and parallel tubular elements defining a delivery duct and a return duct joined one to the other and communicating via a transverse element defining a bypass duct, the valve-body integrating, in a monobloc structure, an on-off delivery valve, an on-off return valve and an on-off bypass valve, the latter provided with a linear shutter to enable/disable the circulation of a thermal-carrier fluid through the bypass duct.

Description:
FILED OF THE INVENTION 
       [0001]    The object of the present invention is a bypass valve. 
       BACKGROUND OF THE INVENTION 
       [0002]    More particularly the present invention relates to an improved bypass valve, especially suitable for the connection of terminal units in which a heat exchange occurs between the environment to be conditioned and a thermal-carrier fluid, in particular a liquid, with the lines of delivery or supply and return of said fluid, with these units typically defined by heat exchangers, fan coil units, batteries for air handling units of the AHU (air handling unit) type in the field of HVAC (heating, ventilation and air conditioning), etc. 
         [0003]    As is known, the terminal units of heat exchange in an HVAC environment are typically connected as schematised in  FIG. 1 , in which a terminal unit “d” is connected to the delivery lines “IN” and return lines “OUT” to define a circuit provided, with reference to the direction of flow of the fluid (indicated by the arrows in  FIG. 1 ), upstream and downstream of the terminal unit “d”, with a series of valves and components suitable for the regulation, management and circulation of the fluid:
       a valve “b” with on-off function for the delivery channel “IN”;   a valve “f” with on-off function for the return channel “OUT”;   an optional valve “e” of manual balancing/regulation or motorised, placed upstream of the valve “f”;   an optional filter “c” with drainage, placed downstream of the valve “b”;   a valve “a” with on-off function for the bypass channel, placed between upstream of the valve “b” and downstream of the valve “f”.       
 
         [0009]    In such a typical circuit configuration, the valves “b” and “f” have always the same function and are always necessary for the purpose of allowing, following a closure thereof, the disconnection of the terminal unit “d” with respect to the supply/return line in order to be able to perform operations of maintenance, installation, disinstallation and the like and co-operate with the bypass valve “a”, which by closing/opening allows the supply/cut-off of the thermal-carrier fluid to the optional terminal units, valves and components placed in series to the valves “b” or “f” as a function of the specific needs. 
         [0010]    For example an operative configuration is possible wherein the valve “a” is closed and the fluid, taking account of the fact that the on-off valves are open, goes to supply the terminal unit “d” (case of standard operations) or a configuration wherein the valve “a” is open with the on-off valves “b” and “f” closed (case of maintenance/assembly/disassembly/replacement of components, without interruption of the flow of the thermal-carrier fluid and, consequently, the supply of the subsequent units) or again a configuration wherein the bypass valve “a” and the on-off valve “f” are closed and the on-off valve “b” open so as to allow the flowing of the fluid through the terminal unit “d” for the emptying of the same and via the filter “c” for the scrubbing of said latter or, further, the bypass valve “a” and the on-off valve “b” are closed and the fluid traverses the on-off valve “f” and the terminal unit “d” to then pass through the filter “c” in order to scrub the terminal unit and eliminate possible impurities introduced. 
         [0011]    Taking account of the fact that in the circuits for handling the terminal units the on-off delivery, return and bypass valves are always present, installers are obliged, for each of the terminal units present in the circuit (at times also multiple), to replicate many times the assembly of the aforesaid valves one with the other and with the two delivery and return lines and need, as well as the three valves (typically of the ball, shutter or globe type), two T-shaped unions and further eight connections (threaded or welded or with pressing) for the internal connection and to the delivery and return lines. 
         [0012]    What is stated above configures an important disadvantage linked to the high number of components necessary, to the definition of the circuit, to the time used for the formation of the same and to the consequent and correlated costs (production, labour, etc.). 
         [0013]    In order to resolve this disadvantage types of valves have been developed with an H-shaped configuration in which the bypass channel is connected, as rigidly as possible, to the delivery and to the return channels. 
         [0014]    However, these known and improved types of valves also have some major disadvantages linked to the problems of seal and to the cost of production. 
         [0015]    For example, models of H-shaped valves are present on the market with bypass channels which have threaded joints situated in any point between the delivery channel and the return one in order to allow changes to the gauge (i.e. the distance between the delivery line and the return one) or to allow the housing in this channel of an on-off bypass valve with spherical shutter or in any case of the rotating type. 
         [0016]    However the assembly of such a type of valve, on the one hand, to the delivery and return lines with fixed gauge and, on the other hand, to the two corresponding inlets on the terminal unit with gauge likewise fixed, determines the generation of stresses of traction, flexure and torsion on the bypass arm, i.e. of mechanical stresses which can damage the joints and, consequently, cause losses of thermal-carrier fluid in the bypass channel in the direction of the external environment. 
         [0017]    Further constructional solutions with an H-shaped configuration do not integrate the on-off delivery and/or return valves which are mounted separately, solving in this way, only partially, the problems linked to the costs and to the times of manufacture/installation, continuing to entail additional costs linked to the need to have to connect the two delivery and return sections with the two on-off delivery and return valves. 
         [0018]    This solution also has further major disadvantages linked to the presence of the joints formed by the installer which, stressed by the manoeuvres of assembly, can give rise to leaks outwards. 
         [0019]    According to a further constructional solution, the H-shaped valve has a monobloc bypass channel inside whereof an on-off valve is housed with spherical shutter or another traditional type. 
         [0020]    For example document U.S. 2012/291901 describes an H-shaped valve comprising an inlet duct, an outlet duct and a bypass duct, each one internally and respectively provided with an inlet valve, with an outlet valve and with a bypass valve and, moreover, said H-shaped valve comprises an actuator device by means of which it is possible to control the simultaneous opening/closing of the three valves, so as to to change from an operative condition to a bypass condition necessary for work of maintenance, repair and the like of the apparatus whereto this H-shaped valve is connected. 
         [0021]    However this solution also has some major disadvantages linked to the fact that it has the main purpose of limiting the release of liquid at the act of disconnection of the cooling circuit of an electronic unit in the case of maintenance work to avoid possible short circuits, with this limitation of the release of liquid performed by actuating simultaneously the valves (delivery, return and bypass). However it does not allow an independent combination of the states of opening/closing of the single valves useful for performing different functions such as, for example, the standard supply of a terminal unit, the exclusion of a terminal unit without the interruption of the supply for the units placed in series to said excluded unit, direct and reverse scrubbing, etc. 
         [0022]    A further disadvantage is linked to the strong stresses on the bypass channel which can alter the geometry of the seat of the pin of manoeuvre of the shutter with consequent possible leaks outwards of the thermal-carrier liquid. 
         [0023]    This aforesaid disadvantage can be resolved by using a different type of valve provided with a monobloc bypass channel without bypass valve and two valves with rotating shutter with three ways housed in two T-shaped intersections between the bypass delivery/channel and bypass return/channel sections. 
         [0024]    However this solution, even if effective as regards the aspect linked to the leaks outwards of the thermal-carrier fluid, is also characterised by a high cost and by the poor operative clarity and practicality of use. 
         [0025]    Another type of bypass valve, as well as the disadvantages of the configurations described above, requires complex and costly machining operations off-plane of the pipes of the seat of the pin for the housing of the ball type shutter of the bypass section. 
       SUMMARY OF THE INVENTION 
       [0026]    The object of the present invention is that of obviating the disadvantages stated above. 
         [0027]    More particularly the object of the present invention is that of providing an improved bypass valve with an H-shaped configuration and monobloc structure suitable for allowing the maintaining of the monobloc layout structure with the integration of the two delivery and return valves also in the case of a reduced gauge (40 mm) typical of small terminal units. 
         [0028]    A further object of the present invention is that of providing a bypass valve suitable for lowering the risk of leaks outwards of the thermal-carrier fluid. 
         [0029]    A further object of the present invention is that of providing a bypass valve with monobloc structure which does not require long and costly machining cycles such as, for example, machining operations off-plane of the pipes. 
         [0030]    A further object of the present invention is that of providing a bypass valve which is of high operational and use clarity. 
         [0031]    A further object of the present invention is to make available to users an improved bypass valve suitable for ensuring a high level of resistance and reliability. 
         [0032]    These and other objects are achieved by the invention which has the features as claimed in claim  1 . 
         [0033]    According to the invention an improved bypass valve is provided, comprising an H-shaped valve-body with two opposed and parallel tubular elements defining a delivery duct and a return duct joined one to the other and communicating by means of a transverse element defining a bypass duct, integrating, in a monobloc structure, an on-off delivery valve, an on-off return valve and an on-off bypass valve with said latter provided with a linear shutter to enable/disable the circulation of a thermal-carrier to fluid through said bypass duct. 
         [0034]    Advantageous embodiments of the invention are disclosed by the dependent claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0035]    The constructional and functional features of the improved bypass valve of the present invention will be made clearer by the following detailed description, in which reference is made to the accompanying drawings which represent a preferred and non-limiting embodiment thereof and in which: 
           [0036]      FIG. 1  represents a hydraulic circuit diagram depicting the connection of a traditional bypass valve with respect to a terminal unit; 
           [0037]      FIG. 2  represents schematically a front view of the bypass valve of the invention; 
           [0038]      FIG. 3  represents schematically a view from above of the bypass valve of  FIG. 2 ; 
           [0039]      FIG. 4  represents schematically a view from below of the valve of the invention of  FIG. 2 ; 
           [0040]      FIG. 5  represents at schematic level a section view of the valve of the invention along a plane A-A as per  FIG. 2 ; 
           [0041]      FIG. 6  represents at schematic level a section view of the valve of the invention along a plane B-B as per  FIG. 3 ; 
           [0042]      FIG. 7  represents at schematic level a section view of the valve of the invention along a plane C-C as per  FIG. 2 ; 
           [0043]      FIG. 8  represents, schematically, a blown-up axonometric view of the bypass valve of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0044]    Referring to the aforesaid drawings, the bypass valve of the invention, denoted overall by  10  in  FIGS. 2 to 8 , comprises a valve-body  12  made typically in brass, bronze, steel or in another material traditionally suitable for the purpose with a process of hot moulding or melting or the like, shaped like an H with two opposite and parallel tubular elements defining, respectively, a delivery duct  14  and a return duct  16  joined one to the other and communicating by means of a transverse element defining a bypass duct  18 . 
         [0045]    The delivery duct  14  has an inlet  14   a  and an outlet  14   b , opposite one to the other, with the inlet  14   a  provided with a threaded external profile or crown  15  for a connection with a delivery pipe (not shown in the drawings) and the outlet  14   b  provided with a threaded internal profile or crown  17  for the connection with a sleeve  19  whose end, opposite that of connection with respect to the outlet  14   b , is suitable for being connected to an inlet duct, for example, of a terminal unit (not shown) typically by means of a threaded connection  19 ′. 
         [0046]    Likewise the return duct  16  has an outlet  16   a  and an inlet  16   b , opposite one to the other, with the outlet  16   a  provided with a threaded external profile or crown  13  for a connection with a return pipe (not shown in the drawings) and the inlet  16   b  provided with a threaded internal profile or crown  11  for the connection with a sleeve  21  (totally similar to the sleeve  19 ) whose end, opposite that of connection with respect to the inlet  16   b , is suitable for being connected to an outlet duct, for example, of a terminal unit (not shown) typically by means of a threaded connection  21 ′. 
         [0047]    Inside a seat  14   c  of the delivery duct  14  a ball type shutter  20  is placed, provided with a channel  22  for the passage of the thermal-carrier fluid and actuated in rotation (to enable/disable the passage of the fluid) by means of a lever  25 . 
         [0048]    The seal of said shutter with respect to the delivery duct  14  and to the sleeve  19  is guaranteed by at least one pair of opposite sealing rings  24 . 
         [0049]    Moreover said one at least pair of opposite sealing rings  24 , together with the sleeve  19 , allow the ball type shutter  20  to be kept in the seat. 
         [0050]    The assembly described in this way, placed inside the delivery duct, defines an on-off delivery valve. 
         [0051]    A similar ball type shutter  26 , provided with a channel  28 , is placed inside a seat  16   c  of the return duct  16  and is rotatably actuated by means of a lever  30  to enable/disable the flow of the thermal-carrier fluid in the direction of the return pipe. 
         [0052]    The seal of said shutter with respect to the return duct  16  and to the sleeve  21  is guaranteed by at least one pair of opposite sealing rings  32 . 
         [0053]    Moreover said one at least pair of opposite sealing rings, together with the sleeve  21 , allow the ball type shutter  26  to be kept in the seat. 
         [0054]    The assembly described in this way, placed inside the return duct, defines an on-off return valve. 
         [0055]    In accordance with alternative embodiments the shutter suitable for enabling/disabling the passage of the thermal-carrier fluid can be of the conical male, gate, butterfly type or of another known typology/configuration suitable for the purpose. 
         [0056]    The bypass duct  18  has an internal channel  34  or bypass channel suitable for allowing the passage of the thermal-carrier fluid along a bypass path when the terminal heat exchange unit is to be shut off from the supply with the thermal-carrier fluid, while continuing to supply the successive terminal units of the system placed in series with respect to the shut-off unit. Said internal channel places in communication one with the other the delivery duct  14  and the return duct  16 . 
         [0057]    The return duct  16  has an opening  36 , formed coaxially to the internal channel  34  of the bypass duct  18  and on the opposite side with respect to that of connection of the same with respect to the return duct and closed by means of a cap  38 , firmly secured with respect to said opening  36  by means of a threaded connection or another known type of removable connection and provided with one or more seal gaskets  40 . 
         [0058]    The cap  38  has a central through hole  42  coaxial to the internal channel  34  and suitable for inserting a linear shutter  43  according to the methods described below. 
         [0059]    The linear shutter  43  comprises a rod  44  with one end, turned in the direction of the internal channel  34  of the bypass duct  18 , provided with a shutter  46  comprising, optionally, at least one gasket  48  for forming the seal with respect to a seat  34 ′ of the internal channel  34  of the bypass duct  18  for the function detailed here below and an opposite end, projecting with respect to the cap  38 , whereon a knob  50  is fitted (attached to the rod  44  with a screw  51  or with another suitable retaining means) for the movement of said rod  44 . 
         [0060]    In an alternative embodiment the at least one gasket  48  is secured to the seat  34 ′ of the internal channel  34  of the bypass duct  18 . 
         [0061]    The seal between the road  44  and the cap  38  is secured by gaskets  39  (typically O-rings) fitted on the rod. 
         [0062]    The assembly described above and defined by the linear shutter  43  actuated by means of the knob  50  constitutes an on-off valve of the bypass duct. 
         [0063]    Externally and coaxially to the cap  38  a ring  41  is placed (typically an O-ring, preferably coloured) suitable for indicating visually the opening/closing of the bypass duct. In fact, in position of complete closure of the on-off bypass valve, said ring is hidden by the knob  50  and is therefore not visible. 
         [0064]    The indication of the opening/closing of the bypass valve, as an alternative to the use of the coloured ring  41 , can be performed by means of a graduated scale formed on the knob  50  or integral with the valve-body  12  or in another known way. 
         [0065]    According to alternative embodiments, moreover, the linear shutter  43  can be of the type with fixed rod with translation of an internal portion of the shutter or can have a rod with different geometries suitable for reducing the possible load losses. 
         [0066]    Moreover, according to further alternative embodiments, the on-off valve of the bypass duct which, with reference to the preferred embodiment, is placed in the return duct, can be placed in the delivery duct. 
         [0067]    An operator/user, by acting on the levers  25  and  30  of the on-off delivery and return valves and on the knob  50  of the on-off bypass valve, enables/disables the passage of the thermal-carrier fluid through the bypass duct and through the delivery and return ducts, so as to perform possible operations of maintenance or exclude any elements of the circuit as described above with reference to  FIG. 1 . 
         [0068]    As can be seen from the above the advantages that the bypass valve of the invention achieves are clear. 
         [0069]    The improved bypass valve of the present invention, being provided with a linear shutter element suitable for performing the on-off function for enabling/disabling the flowing of the thermal-carrier fluid through the bypass duct, allows advantageously elimination of the many disadvantages linked to the use of a ball type shutter. This is in that the use of a linear shutter does not require the presence of auxiliary seal elements to be inserted in the bypass duct in order to maintain the shutter housed inside its seat. 
         [0070]    A further advantage is represented by the fact that the use of a shutter of the linear type does not require “off-plane” machining operations of the H-shaped valve-body, considerably reducing, in this way, the machining cycles, the correlated times and, consequently, the costs of machining and production. This is in that the reduced number of components which characterise the linear shutter allows the seat to be formed for the same during the operation of drilling of the internal channel of the bypass duct. 
         [0071]    A further advantage is represented by the fact that the bypass valve of the invention integrates three on-off valves in a single monobloc structure, without the need for accessory connections. 
         [0072]    Further advantageous is the fact that the improved bypass valve of the invention is provided with a linear axial shutter, does not require a sufficiently long bypass duct in order to accommodate a valve with spherical shutter and, therefore, it is possible to maintain a monobloc structure with the two delivery and return valves also in the case of a typical reduced gauge, for example, of the small terminal units. 
         [0073]    Further advantageous is the fact that the on-off bypass valve assembly, thanks to the threaded connection of the cap  38  with respect to the valve-body  12 , can easily be removed in order to eliminate possible bulky detritus which can accumulate at the shutter or for the replacement of gaskets or for other different works of maintenance/replacement. 
         [0074]    A further advantage is represented by the fact that the bypass valve as described above allows a greater facility of use and a considerable lowering of possible errors which can influence the correct functioning of the system whereto said valve is connected. In fact the element of manoeuvre of the bypass valve, being placed laterally with respect to the levers of actuation of the on-off delivery and return valves, allows the reduction in the errors during the operations of manoeuvre of the valve reducing, at the same time, the risk of leaving the bypass channel open also during the standard functioning phase. 
         [0075]    Although the invention has been described above with particular reference to one of its embodiments given solely by way of a non-limiting example, numerous changes and variations will appear clear to a person skilled in the art in light of the description given above. The present invention intends, therefore, to embrace all the modifications and the variations that fall within the scope of the following claims.