Abstract:
Connection for connecting a fitting to a water heater or other types of pressure tank. The connection comprises an adapter for permanent fitting to the tank, where the adapter and the fitting comprise complimentary formed parts, namely a holder and a pipe stub. The holder and the pipe stub each have a through boring to provide a fluid connection between the tank and the fitting. A nut is screwed onto the holder. The pipe stub comprises a locking groove for engagement of a locking ring. The nut is arranged to prevent the locking ring from moving axially in relation to the holder, so that the pipe stub is prevented from moving axially in relation to the holder.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority to co-pending Norwegian Application Number 2006 0792, filed Feb. 17, 2006, which claims priority to Norwegian Application Number 2005 4446, filed Sep. 26, 2005, which claims priority to Norwegian Application Number 2005 4055, filed Aug. 31, 2005, which are herein incorporated by reference as if set forth herein.  
       BACKGROUND  
       [0002]     The present invention relates to a connection for connecting a fitting to a water heater or other types of pressure tanks, in accordance with the ingress of the subsequent claim  1 . The invention also relates to parts of the connection in accordance with the ingress of claims  11  and  12 , respectively.  
         [0003]     In the following, fitting is meant to cover all types of valves, connecting pieces, branches, pipe parts or the like, that are desirable to connect to a pressure tank.  
         [0004]     Today, it is common to connect fittings to pressure tanks by a nut being rotary fastened to the fitting or an adapter on the tank in such a way that it cannot slip off the fitting or adapter. The nut is then screwed onto a threaded part of the opposite part and is tightened with a relatively large torque.  
         [0005]     Such a connection cannot be disconnected without the help of tools. There will still be a risk for leaks if the nut is not sufficiently tightened. When the fitting shall be fitted, it must be rotated to the correct position before the nut is tightened completely. This means that the fitting will not be fitted before the pressure tank is in its intended place.  
       SUMMARY  
       [0006]     The present invention aims to provide a connection that simplifies the fitting. This is achieved by the features that appear in the characteristic part of the subsequent claim  1 .  
         [0007]     With the present invention it is achieved that it is possible to fit the fitting tightly and securely to the tank but it is still possible to rotate the fitting 360° to the right position. The position of the fitting is finally locked when the tank is pressurised.  
         [0008]     The fitting can be fitted with the help of fully automatic equipment already during the production of the pressure tank.  
         [0009]     It is possible to fit and remove the fitting by hand without the use of tools or with minimal use of tools and without much force being applied. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0010]     The invention shall now be explained in more detail with reference to the enclosed figures, in which:  
         [0011]      FIG. 1  shows a connection according to the present invention in a first embodiment;  
         [0012]      FIGS. 2-6  show a sequence of how the connection of a fitting takes place with the help of the connection in  FIG. 1 ;  
         [0013]      FIG. 7  shows a detail of the connection in  FIG. 1 ;  
         [0014]      FIG. 8  shows a second embodiment of the present invention;  
         [0015]      FIGS. 9-13  show a third embodiment of the present invention;  
         [0016]      FIG. 14  shows a fourth embodiment of the invention; and  
         [0017]      FIG. 15  shows a fifth embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0018]     A first embodiment of the present invention is shown in  FIG. 1 . Here, a part of a valve housing is shown in the form of a pipe stub  1  and adapter  5  that is adapted to receive the pipe stub  1  internally. The adapter  5  is fitted with a first threaded section  6  for connection to a hot water tank (not shown), for example via threads formed in the wall of the tank, as described in Norwegian Patent Application no 2004 1923. The adapter  5  comprises a flange  7  that forms a contact surface against the wall of the tank. Opposite to the threads  6 , the adapter  5  is fitted with a second threaded section  8 .  
         [0019]     The adapter  5  has a through boring  9  which, inside the first threaded section  6 , is made up of a first straight boring section  10  and, inside the second threaded section  8 , is made up of a second straight boring section  11  with a larger diameter than the first boring section  10 . A conical section  12  extends between the first and the second boring sections  10 ,  11 . There is also a conical section  13  at the extreme end of the second boring section  11 . The part of the adapter  5  that encompasses the second threaded section  8  and the second straight boring section  11  functions as a holder for the connection.  
         [0020]     The pipe stub  1  on the valve housing has, at its extreme end, a first straight external section  14  that goes over into a first conical external section  15 , which in turn goes into a second straight external section  16  with a larger diameter than the first external section  14 . The second straight external section  16  is fitted with two ring-grooves  17  and  18 , each of which has room for an O-ring  19  and  20 .  
         [0021]     Furthermore, the second straight external section  16  goes into a second conical section  21 , which in turn goes into a third straight external section  22  with a larger diameter than the second straight external section  16 . The third external section  22  is fitted with a ring groove  24  for a locking ring  25 . The locking ring is made up of a retaining ring that is split so that the diameter can be enlarged. A bore  23  extends through the pipe stub  1 . The pipe stub  1  is further integrated with a valve housing that can be of any type, in itself known, that shall be connected to the tank.  
         [0022]     A locking nut  27  is in threaded engagement with the second threaded section  8  on the adapter  5  at a threaded section  28  on the nut. Externally, the nut can be fitted with grooves or the like (not shown) to provide good friction when tightened manually.  
         [0023]     Internally, the nut  27  has a first section  29  facing the flange  7 , said section having a larger diameter than the threaded nut section  28 . On the other side of the threaded section  28 , the nut also has a section  30  of a larger diameter than the threaded section  28 . At the end that faces away from the flange  7 , the nut  27  has an inwardly directed flange  31 . At the side of the flange  31  that faces the section  30 , the flange has a recess  32  that is bordered by a shoulder  33 .  
         [0024]     The connection of the pipe stub  1  and the adapter  5  shall now be explained with reference to the  FIGS. 2-6 . When disconnected, the nut  27  sits on the second threaded section  8  of the adapter  5 . Between the adapter  5  and the inwardly facing flange  31  lies the locking ring  25 . This lies loosely on top of the end surface of the adapter  5 .  
         [0025]     When the valve housing with the pipe stub  1  is led into the adapter, it will enter with the first straight section  14  of the smallest diameter. This section functions as a surface of entry and centres the pipe stub  1  in relation to the adapter  5 . The second straight section  16  passes through the locking ring  25  that has a larger internal diameter then the external diameter of the O-rings  19 ,  20 . Thereby, the second conical section  21  meets the locking ring  25 . The conical section  21  will expand the locking ring  25  and force this into the hollow space that is formed by the section  30  of the nut so that the third straight section  22  can be led into the locking ring  25 . At about the same time, the pipe stub  1  enters the first straight boring section  10  in the adapter  5  with the first straight section  14 . The pipe stub  1  is thereby centred in the adapter  5 . When the groove  23  aligns with the locking ring  25 , the locking ring  25  snaps into this. A clear click can be heard and the fitter will know that the valve has been fitted correctly. The O-rings  19 ,  20  are then forming a seal against the second straight boring section  11  in the adapter  5 .  
         [0026]     When the tank is pressurised, the pressure will ensure that the valve housing is somewhat lifted in relation to the adapter  5 , as shown in  FIG. 6 . The locking ring  25  will then be squeezed between one of the walls in the groove  24  and the nut flange  31 .  FIG. 7  shows this in detail. The locking ring is here lying squeezed between the wall  24   a  of the groove  24  and the underside of the flange  31 , where the recess  32  is formed. The recess  32  has a diameter adapted to the diameter of the locking ring  25  when this lies in the groove  24 , i.e. when the locking ring is not stressed, so that the locking ring in the position shown in the  FIGS. 6 and 7  can not move radially outwards. Thus, it is ensured that the locking ring is securely engaged with the groove  24  and the connection has no possibility of becoming loose.  
         [0027]     If the pipe stub  1  shall be released from the adapter  5 , the nut  27  must be made loose. This is preferably tightened manually and will therefore be able to be made loose manually or by gentle force from a tool, for example a pipe spanner. The nut  27  is unscrewed from the second threaded section  8 . Thereby, the valve housing with the pipe stub  1  can be pulled out of the adapter  5 . The locking ring  25  will still sit in the groove  24  and before the valve is fitted again the locking ring  25  must be flipped out of the groove  24 . The nut  27  and the locking ring  25  are thereafter fitted on the adapter as shown in  FIG. 2 , so that the pipe stub can again be led into snapping engagement with the adapter  5 .  
         [0028]      FIG. 8  shows a second embodiment of the invention. The principles of this embodiment are the same as for the embodiment above. Thus, only the differences will be explained, as a person skilled in the art will understand that this second embodiment will, in all respects, have the same features as the first embodiment. Here, the adapter  5  that is to be fastened to the tank is equipped with a pipe stub  1 . This comprises a groove  24  for a locking ring  25 . The valve housing is fitted with a holder  34  that, externally, has a threaded section  35  and, internally, has a groove  17  for an O-ring  19 . A nut  27  is screwed onto the threaded section  35  and the locking ring  25  is placed between the end of the holder  34  and the flange  31  of the nut  27 . The pipe stub  1  is thereafter led into the holder until the locking ring  25  snaps into place in the groove  24 .  
         [0029]     It will be understood that even if only one O-ring is shown in  FIG. 8 , one can also use two O-rings. Two O-rings will offer better safety against leaks. When the valve housing moves forward and backward in the adapter  5  as a consequence of the pressure increasing and decreasing, some fluid will be able to penetrate past the one O-ring. The other O-ring will ensure that this fluid cannot leak out completely.  
         [0030]     One sees in  FIG. 8  that there is no hollow made on the inside of the flange  31  of the nut  27 . This might give a smaller degree of safety against unintended disconnection of the valve housing, but will function satisfactorily in most situations. However, a hollow on the flange of the nut will mean that the connection is at least as safe as the conventional connections used today.  
         [0031]     A third and presently preferred embodiment of the present invention is shown in the  FIGS. 9-13 . Here, a part of a valve housing is also shown, having a pipe stub  1  and an adapter  5  that is adapted to receive the pipe stub  1  inside. The adapter  5  is formed, by and large, as the adapter described in connection with  FIG. 1 . However, it has one straight end  40  with a small rounded tip  46  against the valve housing instead of the conical section  13 .  
         [0032]     The pipe stub  1  of the valve housing is somewhat differently formed than according to the embodiment shown in  FIG. 1 . At its extreme end it has a first straight external section  14  that runs into a conical section  41 . A second straight section  16  follows thereafter. Two grooves  17 ,  18  for O-rings  19 ,  20 , respectively, are formed in the straight section  16 . The second straight section  16  goes into a downwardly directed shoulder  42 . The shoulder  42  leads to a third straight external section  22  with a larger diameter than the second external section  16 .  
         [0033]     The third straight external section  22  is fitted with a ring groove  24  for a locking ring  25 . The locking ring  25  is made up of a retaining ring with a circular or rounded cross section, which is split so that the diameter can be expanded. The groove  24  has an upper sidewall  43  that extends radially in relation to the longitudinal axis of the pipe stub  1  and a lower sidewall  44  that extends diagonally downwards. A boring  23  extends through the pipe stub  1 .  
         [0034]     A locking nut  27  stands in the same way as in the embodiment in  FIG. 1 , in threaded engagement with the second threaded section  8  of the adapter  5  at a nut threaded section  28 . However, the nut is formed somewhat differently from the nut in  FIG. 1 , as the flange  31  has a conical boring  45  facing the pipe stub  1 . The boring  45  tapers from above in towards the pipe stub  1  and forms an acute angle with the longitudinal direction of the pipe stub. A small shoulder  33  is on the underside of the flange  31 .  
         [0035]     The connection of the pipe stub  1  and the adapter  5  shall now be explained with reference to the  FIGS. 9-13  and disconnection with reference to  FIG. 14 . When disconnected the nut  27  sits on the second threaded section  8  of the adapter  5 , in the same way as explained in connection with  FIG. 1 . However, the locking ring  25  is now placed in the groove  24  in advance.  
         [0036]     When the valve housing with the pipe stub  1  is led into the adapter, it will first enter with the first straight section  14 , which functions as a guiding for the pipe stub. Thereafter, the conical section  41  will enter and centre the pipe stub  1  in relation to the adaptor  5  in that the conical section  41  meets the rounding off  46 . The centring also takes place in that the pipe stub meets the conical section  12 .  
         [0037]     When the section  16  of the pipe stub  1  has entered the boring  11  of the adapter, as shown in  FIG. 10 , the pipe stub  1  can be led into the adapter until the conical section  41  of the pipe stub encounters the conical section  12  of the adapter, as shown in  FIG. 12 . During this insertion, the locking ring  25  will meet the walls in the conical boring  45  of the nut  27 , as shown in  FIG. 10 , and be forced inward in the groove  24 , as shown in  FIG. 11 . The locking ring will then lie against the upper wall  43  of the groove  24  and be forced downwards with this help of this.  
         [0038]     When the locking ring  25  has come through the conical boring  45 , it will expand by its own spring force and lie against the nut  27  on the underside of the shoulder  33 , as shown in  FIG. 12 .  
         [0039]     When the tank is pressurised, the pressure will ensure that the valve housing is somewhat lifted with regard to the adapter  5 , as shown in  FIG. 13 . The locking ring  25  will then be squeezed between the lower wall  44  of the groove  24  and the shoulder  33  on the underside of the flange  31  of the nut. Because of the conical form of the wall  44 , the locking ring  25  will be forced outwards and to a secure engagement with the shoulder  33  and the wall section  30  of the nut. In this way the locking ring is influenced by two opposite forces, a first force from the wall  44  that works diagonally upwards and outwards and an opposite directed force that works from the shoulder  33  and the wall  30  diagonally downwards and inwards. Thus, it is ensured that the locking ring  25  is in secure engagement with the groove  24  and the nut  27 , and the connection has no possibility of becoming loose.  
         [0040]     In the same way as in the embodiment according to  FIG. 1 , the nut  27  must be made loose if the pipe stub  1  shall be released from the adapter  5 . The valve housing with the pipe stub  1  can thereby be pulled out of the adapter  5 , as shown in  FIG. 14 . The locking ring  25  will still sit in the groove  24  and before the valve is fitted again, it can, if necessary, be flipped out of the groove  24 . However, it is possible to fit the valve while the nut  27  sits on the pipe stub  1 . The fitting will then be in the same way is in a traditional valve connection.  
         [0041]      FIG. 15  shows a fifth embodiment of the invention. The principles for this embodiment are the same as for the embodiment above. This embodiment does also have substantially the same characteristics as the previous embodiment and is similarly preferred. Only the differences in relation to the previous embodiment will be explained, as a person skilled in the art will understand that in all respects this fifth embodiment will have the same features as in the previous embodiment. Here the adapter  5  that shall be fastened to the tank is fitted with a pipe stub  1 . This comprises a groove  24  for a locking ring  25 . The valve housing is fitted with a holder  34  that, externally, has a threaded section  35  and, internally, has a groove  17  for O-ring  19 . A nut  27  is screwed onto the threaded section  35  and the locking ring  25  is placed in the groove  24 . The pipe stub  1  is thereafter led into the holder until the locking ring  25  snaps into place behind the shoulder  33  of the nut  27 . Here, the locking ring will prevent disconnection in the same way as in the embodiment according to the  FIGS. 9-14 .  
         [0042]     For the embodiments according to the  FIGS. 9-15 , there are no recesses on the inside of the flange  31  of the nut  27 . This has no consequence for the shape of the locking ring  25  with circular or, in another way, rounded cross section and the conical side wall  44 , which together ensure that the locking ring does not unintentionally come out of the engagement.  
         [0043]     Instead of having a threaded connection between the nut and the adapter and the holder, respectively, the nut in all the above mentioned embodiments can be fastened, for example, with the help of a bayonet connection, removable locking taps or an annular spring.