Abstract:
A pressure vessel including a mounting block for supporting and retaining an inlet and an outlet tube to the pressure vessel. The mounting block includes a valve that communicates with an interior of the vessel and fastens the mounting block to a top of the pressure vessel. The mounting block enables access to the interior of the housing for accessories such as the valve, a sight glass, or a pressure switch, and the accessories can be either permanently or removably attached to the pressure vessel at the top or sides thereof. The mounting block may accommodate more than one valve.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to pressure vessels and fixing a tube thereto. More particularly, the present invention relates to fixing a tube to a pressure vessel used in an air-conditioning system, such as an accumulator or receiver. 
     2. Description of the Prior Art 
     Presently known in the art of tubular connections to a pressure vessel is a mounting block or block joint. Prior art mounting blocks support one or more tubes and facilitate connecting the tubes to the pressure vessel. Prior art mounting blocks are typically attached to a top of the pressure vessel by bolts or screws. This prior art method is unnecessarily complicated and costly for connecting tubes to a pressure vessel. 
     In contrast, a more simplified prior art method is disclosed in U.S. Pat. No. 4,707,999 awarded to Ohta et al. Ohta et al. attempt to simplify the mounting block connection method by incorporating a block joint on a receiver housing that has inlet and outlet tubes detachably connected thereto. Accordingly, Ohta et al. disclose a receiver housing having a flat top with the block joint connected to an upper surface thereto. The block joint has an opening on one surface for receiving a tube and a protrusion on the opposite surface for insertion into an opening at the top of the receiver housing. Ohta et al. further disclose two methods of connecting the block joint to the top of the receiver housing. One method provides a screw socket into which a fixing bolt is screwed, securing the block joint to the receiver housing. An alternative method provides a bolt having a lock nut. The combination of the bolt and the lock nut fix the block joint to the top of the housing. 
     In addition, to attach accessories such as pressure switches and sight glasses to the receiver housing, Ohta et al. disclose a modified block joint and multiple block joints. The modified block joint and the multiple block joints are fixed to the top of the receiver housing in the same manner as described above, by a bolt and lock nut arrangement. A pressure switch or sight glass must communicate directly with the interior of the pressure vessel. Therefore, in prior art block joint arrangements like the one disclosed in Ohta et al., access openings to the interior of the vessel are required in addition to the openings for the inlet and outlet tubes. 
     Such sight glass and pressure switch accessories are desirable features of an air-conditioning system for trouble-shooting and maintaining the system. However, the modified block joint and multiple block joints disclosed by Ohta et al. are very costly and add unwanted complexity to the air-conditioning system because of the additional access openings required for communication with the pressure vessel and the additional mounting blocks required for maintaining the accessory connections. 
     An alternative to the above-described mounting block is a fluid direction tube and bracket assembly as disclosed in U.S. Pat. No. 5,071,172 to Gross. Gross discloses a flexible bracket having a plurality of fluid direction tubes. The entire assembly must be made of a flexible material such as thermoplastic or glass reinforced polymer resin to achieve the necessary flexing and bending required of the bracket for proper assembly. Gross further discloses a chamfered receiving bore that receives a matching chamfer on the bracket assembly. Flexing and stretching the bracket is necessary to ensure proper alignment between the fluid direction tubes and the receiving bores, and an airtight pressure fit holds the bracket assembly in the receiving bores. 
     The assembly disclosed above in Gross is directed to an automobile engine body or part thereof. It is questionable whether the pressure fit could withstand the excessive pressure an accumulator is exposed to. Also, the tubular connections must accommodate the harsh environment and excessive pressures of the liquid refrigerant and it is not likely that a flexible thermoplastic resin could withstand exposure to such a harsh environment. 
     Another alternative in U.S. Pat. No. 5,072,710 to Washizu discloses a fuel delivery rail assembly for supplying fuel to a plurality of fuel injectors in an engine. The assembly disclosed in Washizu is an elongated conduit having a rectangular cross section and a plurality of tubular sockets. The conduit and each tubular socket are connected by deforming an annular extension of the tubular socket about a wall opening of the conduit, or by deforming an annular projection from the wall opening in the conduit about an internal shoulder in the tubular socket. A seal member is disposed between the surface of the conduit and the socket to prevent fuel leaks. 
     Accordingly, the conduit and socket assembly disclosed in Washizu is such that the sockets are permanently attached to the conduit and the upper side of the socket is adapted to receive a tip of a fuel injector only. The conduit wall must have a flat surface for seating the socket on the wall and maintaining the sealing effect of the seal member. The socket disclosed in Washizu is not capable of connecting any other device other than a fuel injector and does not have the capability of mounting or maintaining tubular connections other than the socket itself. 
     Therefore, what is needed is a simple reliable means to connect tubes to a pressure vessel and at the same time accommodate accessories, such as valves, pressure switches, or sight glasses, without excessive modifications, multiple parts, or unnecessary complexity. 
     SUMMARY OF THE INVENTION 
     The pressure vessel of the present invention includes a minimum of parts and simplifies the manufacture of pressure vessels according to known designs. In general, the present invention involves a pressure vessel including a mounting block for supporting and retaining inlet and outlet tubes through a top and into an interior of the pressure vessel. Additionally, a valve or other accessory fastens the mounting block to the top of the pressure vessel and also communicates with the interior of the pressure vessel. 
     More specifically, in the present invention the valve has an externally threaded stem and is attached to the top, or side of the pressure vessel housing. The valve can be either permanently or removably attached to the housing. Further, a mounting block has passages for retaining the tubes to the pressure vessel as is known in the art. However, the mounting block of the present invention has an additional passage for receiving the valve, a pressure switch, a sight glass, a charging device, or other such accessory. A nut spins over the threaded valve stem and securely engages the mounting block to the top of the pressure vessel housing. 
     Moreover, more than one valve can be accommodated by the mounting block of the present invention. The valve or valves can be permanently attached to the top of the housing by welding or brazing. It is also possible to machine the valve as part of the top. Alternatively, a threaded valve can be received in a threaded opening in the top of the housing, resulting in a removably attached valve. The threaded connection may be sealed using O-rings or the like. 
     Accordingly, it is an object of the present invention to reduce the weight and cost of known pressure vessels by simplifying the pressure vessel through combination and elimination of tube mounting hardware. 
     It is another object of the present invention to reduce the number of braze joints and thereby reduce manufacturing costs and improve product quality. Braze joints are subject to leaks, and elimination of the braze joints improves the quality of the product by reducing the potential for such leaks. 
     It is yet another object of the present invention to provide a through path to the interior of the vessel through a valve or other device mounted to the pressure vessel. The valve also functions as a fastener for a mounting block for the inlet and outlet tubes. 
    
    
     These objects, features, and advantages of the present invention will become readily apparent from the following detailed description of the preferred embodiment when taken in connection with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational, exploded view shown in partial cross section of a pressure vessel of the present invention; 
     FIG. 2 is a side view of the top of the pressure vessel, the valve, the nut, the mounting block, and the inlet and outlet tubes of the pressure vessel of the present invention; 
     FIG. 3 is a plan view of the pressure vessel top, the valve, the nut, the mounting block, and the inlet and outlet tubes of the present invention; 
     FIG. 4 is a cross-sectional view of the top and valve; 
     FIG. 5 is a plan view of another embodiment of the top of the present invention having multiple valves, one valve having a pressure switch attached; 
     FIG. 6 is a side view of the embodiment of FIG. 5; 
     FIG. 7 is a side view shown in partial cross section of a further embodiment of the top and valve of the present invention, wherein the valve is removably attached to the top and sealed in radial and axial directions using O-rings; 
     FIG. 8 is a side view, shown in partial cross section, of an embodiment of a pressure vessel of the present invention wherein the mounting block is attached at the sides of the pressure vessel; 
     FIG. 9 is a top view of the mounting block of the embodiment shown in FIG. 8; 
     FIG. 10 is a side view shown in partial cross section of a pressure vessel top having the mounting block of the present invention attached to the sides of the vessel&#39;s top; 
     FIG. 11 is a top view of the mounting block having a configuration that is attached to the sides of the pressure vessel top using studs and nuts and to the top using a fastening valve; and 
     FIG. 12 is a top view of another embodiment of a top and mounting block of the present invention wherein a valve is incorporated into one side of the vessel&#39;s top and accommodated by the mounting block. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A first embodiment of a pressure vessel  10  constructed in accordance with the present invention is shown in FIG. 1, wherein the pressure vessel  10  has a housing  12  and a top  11  that securely engages to the housing  12 . For purposes of illustration, FIG. 1 is an exploded view of the housing  12  and the top I  1 . The top  1   1  has an inlet hole  13 , an outlet hole  14 , and a mounting hole  15 . The inlet and outlet holes  13  and  14  receive tubes  2  that extend into an interior  1   2 a of the housing  12  as in a conventional accumulator assembly. 
     Referring now to FIGS. 2 and 3, a valve  19 , or other vessel accessory, may be either permanently or removably attached to the top  11 . The valve  19  has an externally threaded stem portion  18  that extends beyond the top  11  to outside of the pressure vessel (not shown). Further, a mounting block  17  is located on the top I  1  and effectively traps the tubes  2  between the mounting block  17  and the top  11  using two openings  17   b  and  17   c.  The valve  19  extends through an opening  17   a  in the mounting block  17 . The openings  17   a / 17   b / 17   c  of the mounting block  17  align with the holes  13 / 14 / 15  of the top. The mounting block  17  is fastened to the top  11  by a nut  3  that is securely engaged to the externally threaded stem portion  18  of the valve. One skilled in the art will recognize that any alternative means to fasten the valve  19  to the mounting block  17  may be used, such as a circlip, integral locking features, or other well known retention method. 
     In general, there are several methods that may be used for permanently attaching the valve  19  to the top  11  of the present invention. FIG. 4 illustrates an example of how permanent attachment can be accomplished by welding or brazing the valve  19  to the top  11 . Alternatively the valve  19  can be machined as part of the top  11  (not shown). An alternative in which the valve is removably attached to the top is best shown in the embodiment of FIG. 7 wherein a valve  39  is shown secured to a top  31  using a threaded connection. Internal threads  34  are provided on a mounting hole  35  of the top  31 . Additionally, external lower threads  38   b  are provided on the portion of a valve stem  38  that communicates with the internal threads  34  of the mounting hole  35 . The connection may be sealed by including one or more O-rings  32  and  33  strategically placed radially and axially around a portion of the valve stem  38  in direct communication with the top  31 . The first O-ring  32  is sandwiched between the upper region of the external lower threads  38   b  of the valve  39  and the top  31 . The second O-ring  33  is sandwiched between the valve  39  and the top  31 , below the external lower threads  38   b . Finally, external upper threads  38   a  on the valve  39  communicate with a nut (not shown) located over the valve  39  and above the top  31 . 
     FIGS. 5 and 6 show another embodiment of a pressure vessel top  21  of the present invention having more than one access port. A plurality of valves  29   a  and  29   b  are part of the top  21 . In a pressure vessel having more than one valve, more than one mounting block  27   a  and  27   b  may be used, but is not necessary. Multiple valves on the vessel&#39;s top  21  can be accommodated by one mounting block (not shown). 
     The valves  29   a / 29   b  increase the functionality of the pressure vessel without the necessity of adding unwanted additional access openings to the housing  12 . Many pressure vessels utilize pressure switches, sight glasses, charging devices, and other accessories, instead of or in addition to the valves  29   a / 29   b.  The present invention provides a ready and continuous passage for such accessories without additional openings to the interior of the vessel. For example, FIGS. 5 and 6 demonstrate a pressure switch  4  attached to a valve  29   a  of the present invention. 
     The preferred embodiment of the present invention, as shown in FIG. 8, provides another structure for mounting a mounting block  47 . FIG. 8 shows a pressure vessel  40  having a top end  41 . The top end  41  has two sides  41   a  and  41   b  opposite one another, an inlet opening  43 , and an outlet opening  44 . The side  41   b  of the pressure vessel has an opening  45  for receiving the valve  39  of the present invention. The side  41   a  also has an opening  46  for receiving a stud  49  or other fastening member. A combination of both the valve  39  and the nut  3  on one side and the stud  49  and a nut  49   a  on the other can be used. Other configurations, such as a valve on either side (not shown), are also contemplated. 
     Furthermore, the openings  45  and  46  are used to hold the mounting block  47  on the top end  41 . The external lower threads  38   b  of the stem  38  are received in the opening  45  and the O-ring  32  is used to seal the connection. The valve  39  is held to the mounting block  47  by the nut  3  that is secured over the external upper threads  38   a.  The valve  39  and nut  3  and the stud  49  and nut  49   a  hold the mounting block  47  to the vessel, while the mounting block  47  secures the inlet and outlet tubes  2  to the pressure vessel  40 . Slots  48  in the mounting block  47  provide means to position the mounting block  47  over the tubes  2  and prevent the mounting block  47  from rotating on the top end  41  as shown in FIG.  9 . 
     Referring now to the embodiment shown in FIG. 10, the mounting block  47  is shown with the inlet and outlet tubes  2  in place. FIG. 10 also shows the stud  49  and nut  49   a  and the valve  39  and nut  3  securing the mounting block  47  to a top  51  that is a separate piece from the pressure vessel housing (not shown). The valve  39  is sealed by the O-ring  32  to the top  51 . 
     Yet another embodiment is shown in FIG. 11 by a top view wherein the valve  39  is incorporated on the top  51  and additional side attachments are made using the stud  49  and nut  49   a  arrangement. A side attached mounting block  57  has a slotted portion  57   a  that receives the tubes  2  and prevents the mounting block  57  from rotating on the vessel&#39;s top  51 . 
     Finally, FIG. 12 is an embodiment of a mounting block  67  having a different slotted portion  67   a  for holding the tubes  2  and preventing rotation of the mounting block  67 . The valve  39  and the nut  3  secure the mounting block  67  to a top  61 . 
     An advantage of the present invention is that the valve provides communication through the top to the interior of the vessel housing and has an additional function of providing fastening means for the mounting block. The valve mount system of the present invention eliminates the need for the additional mounting hardware that is normally required in a pressure vessel assembly, such as a stud and nut system. As a result, the present invention is lighter and less expensive than conventional pressure vessel assemblies. 
     An additional advantage of the valve assembly of the present invention is the elimination of a braze joint that is normally required at the inlet and outlet holes. The present invention is more reliable as a result, the potential for leaks that is normally a problem with braze joints is eliminated, and a reduction in manufacturing costs by elimination of the brazing step is realized. 
     Although particular embodiments of the present invention have been illustrated in the accompanying drawings and described in the foregoing detailed description, it is to be understood that the present invention is not to be limited to just the embodiments disclosed. Rearrangements, modifications, and substitutions are possible, without departing from the scope of the claims hereafter.