Abstract:
A mechanical packing system for use for a device allows one or more packing rings to be installed one at a time and die formed in place. A reversible, detachable flange having a key offset from the center is inserted into a key slot of the hub of the mechanical packing system which is also offset during this installation process. When the device is operated, the flange is detached from the hub rotated 180° and the key of the flange is then inserted into the key slot of the hub. A spacer with integral lantern ring and internal bore surface which reduces or prevents marring or galling. A stuffing box of sufficient length to eliminate the need for a spacer or unneeded packing rings.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    The present application claims the priority of U.S. provisional patent application Ser. No. 61/193,106, filed on Oct. 29, 2008, and is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to a mechanical packing system used to seal moving parts of devices such as pumps and valves. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention is directed to a mechanical packing system utilizing a reversible, detachable flange, a hub and a spacer in conjunction with a device for sealing the moving parts of various devices, such as pumps and valves in order to allow linear, axial or a combination of both motions while retaining fluids within an enclosure. 
         [0004]    The system includes a method and system of packing which specifies that one or more packing rings be installed one at a time and die formed in place, under pressure, from an installation device, until a stuffing box is filled. This would allow for each packing ring to be formed in the installed position allowing for the removal of any void or leak path that might be present. Die forming each packing ring one at a time, while loading, results in a far more reliable method of packing than if all the rings were installed at one time when a packing gland is put into place. The reversible flange of the packing gland will allow for its use as an installation tool for the one at a time installation method as well as conventional operation in service. 
         [0005]    The packing gland assembly is provided with a hub onto which the reversible flange would be reversibly attached. A key slot extends around the external surface of the hub and is offset from the center of the hub. The reversible flange is provided with a key extending outwardly from the bottom surface of an inner horseshoe shaped surface and is also offset from the center of that horseshoe shaped surface. Therefore, when one of the packing rings is being installed into the mechanical packing system, the key of the flange would be inserted into the key slot of the hub in one position. During the running or operating position, the flange would be rotated 180° and then the key of the flange would again be inserted into the key slot of the hub. When the flange is attached to the hub and while the packing rings are installed, the flange would be affixed to the hub and would be offset from the hub on one side thereof. When the flange is reversed during the operation of the device, the flange would be affixed to the hub and offset therefrom on the second side of the hub. 
         [0006]    This forming of the packing material in a closed cavity under pressure is commonly referred to as die forming. Die formed packing rings are produced outside of the device they are to be used in and therefore have dimensions that are smaller than the stuffing box they will be installed in to aid in installation. Die forms, thus made, inherently have voids at the major and minor diameter in the amount of the needed clearance required for installation as well as joints where the packing rings join to complete a closed loop. The proposed method of die forming in place eliminates all voids by completely filling the installation space without the clearance voids inherent in preformed rings or rings cut from long stock. The proposed packing gland is made of sufficient strength to die form the packing in place using available stuffing box, shaft, studs and nuts. This method is particularly desirable for shafts exhibiting reciprocating motion such as valves and cylinders. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a side view of the mechanical packing system utilizing a plurality of packing rings with the reversible flange in the running or operating position; 
           [0008]      FIG. 2  is a side view of the mechanical packing system employing only a single piece of packing as occurring while die forming in place during installation; 
           [0009]      FIG. 3A  is a perspective view of a packing gland with a flange in the running or operating position; 
           [0010]      FIG. 3B  is a perspective view of the packing gland with a flange in the die forming position; 
           [0011]      FIG. 4  is an exploded perspective view showing the packing gland removed from the packing gland hub; 
           [0012]      FIG. 5  is a perspective view of one embodiment a spacer; 
           [0013]      FIG. 6  is a perspective view of a second embodiment of the spacer; 
           [0014]      FIG. 7  shows face profiles of the packing gland hub, spacer and throat bushing; 
           [0015]      FIG. 8  is a perspective view of a typical stuffing box designed for the mechanical packing system; and 
           [0016]      FIG. 9  is a perspective view of a third embodiment of the spacer. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]      FIG. 1  illustrates the mechanical sealing means to seal the moving parts of the device, such as a pump or valve or other types of devices. The mechanical sealing device is provided with a packing gland assembly  1  comprising a packing gland flange  4  cooperatively attached to a packing gland hub  5  in a running position. The packing gland assembly is used in conjunction with a stuffing box  2  having a plurality of packing rings  6 . As shown in  FIG. 2 , the number of packing rings can be reduced from six or more, to three more or less packing rings, thereby reducing the time and expense required to pack or re-pack the stuffing box  2 . As illustrated in  FIG. 1 , a standard spacer  3  could be employed. As shown in  FIG. 2 , the number of packing rings is reduced from six to three, thereby reducing the time and expense required to pack or re-pack the stuffing box glands, and utilizing a spacer  7  with an extended length. 
         [0018]      FIG. 2  shows the use of the spacer  7  which fills the space of the stuffing box  2 , thereby reducing the number of packing rings to three. This is accomplished by utilizing an extended length spacer as illustrated in  FIGS. 5 ,  6  and  9 .  FIG. 2  also shows the mechanical packing system with hub  8  in the loading, die forming position in which the first ring of packing material  9  is installed and is in contact with the spacer. This packing system utilizes packing materials which allow for a three ring, more or less, installation resulting in a dripless or a nearly dripless installation. Each additional ring, when installed, would then contact an adjacent ring. 
         [0019]      FIGS. 3A ,  3 B and  4  show various views of the packing gland flange  10  and the hub  11 . The flange  10  is designed to be inserted over the hub  11  in both the running position as illustrated in  FIG. 3A  and the loading or die forming position as shown in  FIG. 3B . The flange  10  would extend around the periphery of a portion of the hub  11  which is provided with a profile face  14 A as illustrated in  FIG. 4 . The hub  11  can be constructed from a single piece of material or from two complementary halves which are split at  12 A and  12 B of the profile face  14 A. 
         [0020]    As shown in  FIG. 4 , the hub  11  is provided with a key slot  14  extending around the hub  11  for approximately 180° . However, the exact length of this key slot  14  is not important. What is important is that the key slot  14  is offset from the center of the hub  11 . The flange  10  is provided with an inner horseshoe shaped surface  42  having a key  13  running for its entire length and extending outwardly therefrom. Similar to the key slot  14 , the key  13  is offset from the center of the horseshoe shaped surface  42 . Therefore, as shown in  FIG. 3A , when the key  13  is inserted into the key slot  14 , the packing gland flange  10  and the hub  11  would be in the running position of the mechanical device with the flange  10  offset onto one side of the hub  11 . However, when the packing flange  10  is reversed and the key  13  is inserted into the key slot  14  as shown in  FIG. 3B , the packing gland with the flange would be in the loading position with the flange  10  offset onto the second side of the hub  11 . Therefore, when each of the packing rings  6  is inserted into the stuffing box  2 , the packing gland and flange would be shown in  FIG. 3B . However, when the mechanical device is operating, the packing gland and flange would be in the position shown in  FIG. 3A . The flange  10  is provided with holes  38  and  40  which are used to affix the packing gland assembly  1  to the mechanical enclosure through the utilization of bolts  32  and their respective nuts  30 ,  36 . 
         [0021]      FIGS. 5 ,  6  and  9  show various embodiments of the spacer  3 . Similar to the hub shown in  FIGS. 3A ,  3 B and  4 , the spacer as shown in  FIG. 5  can consist of two pieces having a joint  16 A extending from a first profile face  44  through an extended length  15 A to a second profile face  15 . The spacer can be provided with a bore which may be tapered to aid in the release of solids that may be present in the fluids. The bore could be straight with the clearance selected to control the flow of fluids. The spacer includes an integral lantern ring  16  recessed into and extending around the outer or inner surface of the spacer. A number of holes  17  are used to flush fluid from the packing system and along with the thickness of the lantern ring  16  provide for controlled amounts of thermal conductivity from the packing contacting the profile face  44  and the extended length  15 A. The thickness of the integral lantern ring could vary for the purpose of controlling thermal conductivity. 
         [0022]    As illustrated in  FIG. 6 , the spacer  3  is produced in one piece from a thin wall tubing  18 . Similarly, the embodiment shown in  FIG. 5 , an integral lantern ring is provided having a plurality of holes for flushing fluid from the packing system. 
         [0023]      FIG. 9  shows the spacer  15  within an additional liner  15 C which can be made of various materials chosen to prevent marring or galling when installed around the shaft or valve stem to be sealed. Holes  17  may be varied in size and number and the wall thickness of the material under integral lantern ring groove  16  may be varied to control the heat transfer from the packing to the liner  15 C which may be made from material of various melting points. This is an improvement over previous designs which may be made of materials which deteriorate or melt under high heat conditions generated by the packing. Bore  18 A is sized to control flow of the flush fluid introduced into the integral lantern ring  16  and transferred to the interior of the spacer by way of holes  17 . Materials of construction of liner  15 C may be but not limited to metal, plastic, composite, carbon etc. 
         [0024]    The spacer of the present invention represents an improvement in existing spacers in that it uses the poor heat transmission qualities of stainless steel to protect the usually low melting point materials used in making spacers that do not mark or gall the shaft. By using a large number of holes and making the lantern ring wall thin the heat transfer can be greatly reduced from the spacer face in contact with the packing to the rests to the spacer holding the liner material. 
         [0025]    Returning to  FIGS. 3A ,  3 B and  4 , the key slot  14  forms a flat which does not allow rotation of the hub  11  within the flange  10  when the key  13  is inserted into the key slot  14  in both the running position as shown in  FIG. 3A , as well as the loading position as illustrated with respect to  FIG. 3B . The flange  10  is removable and therefore is out of the way during the packing or repacking process. 
         [0026]    Since the packing gland assembly  1  is utilized in the insulation of the packing rings  6 , it is important that the hub be of sufficient length to reach the first packing ring during the loading or packing of the stuffing box  2 . More than one key slot  14  may be required in a particular hub to reach the desired depth in a stuffing box. 
         [0027]    The spacer shown in  FIG. 5  can be constructed from two pieces  15 A and  15 B and would have circular mating faces  16 A where the joints aid in the stability during the assembly process and reduce leakage from the interior to the exterior of the spacer. The spacer could be constructed as one piece as shown in  FIG. 6 . The spacer  15  can be constructed of a variety of materials including but not limited to metal, ceramic, plastic and composite materials. 
         [0028]    As illustrated in  FIG. 8 , a stuffing box  21  stuffing box includes a throat bushing  22  and a profile face  23 . Stuffing box  21  should be of sufficient depth so that it can be utilized if only three, more or less, rings of packing material are installed and eliminate the need for a lantern ring or spacer. 
         [0029]    The stuffing box would have a profile  23  selected from the profiles  25 ,  26 ,  27  and  28  illustrated in  FIG. 7 . This setup of profiles would increase the density of the packing at various radial positions, thereby reducing the chance of leak path developing along the inner circumference of the packing by use of the step change in face  24 , the outer circumference of the packing by use of the step change in the face  25 , the inner circumference of the packing by use of an angular change in the face  26  or the outer circumference of the packing by use of the angular change in the face  27 . The chance of leak paths developing would also be reduced through the use of a middle or lap joint area of the packing by an angular step projection in the center of the face as shown by  28 ,  29 . 
         [0030]    During the operation of the mechanical packing system, the volume of the each individual packing ring and therefore the entire volume of multiple packing rings as a unit would decrease. Therefore, one or more packing rings must be added to the device. When this occurs, the flange is removed and one or more packing rings can then be inserted next to the last packing ring. In this case, the flange is inserted over the hub  11  into the running position, wherein the device can again operate. In the case in which no additional packing rings are available, it is possible to then reverse the position of the packing ring such that it is in the insulation position at which time the device would be able to operate. 
         [0031]    The invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to embraced therein.