Abstract:
A bearing with an integral diverted lantern ring for installation into the seal cavity of a rotary mechanical device to provide a bearing surface and allow for flush fluid to engage the shaft closer to the motor end is provided. The bearing eliminates whip in a rotating shaft and is split to allow easy installation over an installed shaft. The bearing is substantially cylindrical with an inner bore closely approximating the outer diameter of the shaft. The diverted lantern ring includes an outer groove at the impeller end on the outer surface at a flush port and a groove on the inner surface at a location closer to the motor end. Flush fluid channels are provided between the outer groove and inner groove of the bearing. The purpose is to redirect the external flush from the impeller end on the OD to the motor end on the ID, thus repositioning the flush deposit on the sleeve, under the bearing. This allows the throttling characteristic of the close clearance bearing surface to increase.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates to an improved bearing with an integral lantern ring for a rotary mechanical device and, more particularly, to an improved bearing with the lantern ring having offset outer and inner flush holes. 
         [0002]    Rotary mechanical devices, such as mixers and centrifugal pumps, include an impeller mounted on a shaft which is driven by an electrical motor. The shaft passes through a seal cavity or a stuffing box defined by a cylindrical cavity in the device housing. The shaft is supported by bearings at the motor end, and seals are placed in the stuffing box to engage the shaft to prevent fluid from passing through the seal cavity and reaching the bearing and the motor, causing damage to both. 
         [0003]    In mechanical pumps, chemical fluids or solvents being pumped, many of which are corrosive, enter the seal cavity. Accordingly, it is important that appropriate packing material is placed within the seal cavity. In addition, fluid such as seal water is pumped into the seal cavity through a flush port to prevent the fluid being pumped or mixed from travelling along the shaft to the bearings and motor and to provide lubricant to the packing. Over extended use, the pump shaft may develop a whip as the bearings wear. Thus, it is highly desirable to provide a sealing system that provides an effective seal and an additional bearing surface to reduce the whip that can occur as the shaft rotates, thus controlling the amount of seal fluid entering an outer lantern ring groove in the seal cavity. 
         [0004]    While there are a wide variety of devices available for use in providing sealing in a seal cavity, it is desirable to provide a improved bearing and sealing system providing an additional bearing surface for the impeller end of the shaft and causing a reduction in the pumped or mixed fluid entering the seal cavity to be countered by the seal fluid and packing to provide advantages over available devices. 
       SUMMARY AND OBJECTS OF THE INVENTION 
       [0005]    Generally speaking, in accordance with the invention, an improved bearing with an integral diverted lantern ring for a rotary mechanical device is provided. The bearing is a substantially rigid member with an outer lantern ring groove at one location along the bearing axis and an inner lantern ring groove at another location along the bearing axis, with channels in the bearing wall to direct seal fluid onto the shaft from the inner lantern ring groove. The inner bore of the bearing provides a bearing surface for eliminating whip in the device shaft. The bearing is split to provide easy installation over an installed device shaft. 
         [0006]    The bearing prepared in accordance with the invention is substantially rigid and is typically manufactured of a non-ferrous metal or thermoplastic material for providing an improved bearing surface and resistance to industrial solutions. The inner bore of the bearing closely approximates the outer diameter of the pump shaft. The external surface of the bearing includes a groove for receiving seal fluid with channels to an inner groove to form an internal lantern ring. Typically, the outer lantern ring groove is located at a flush inlet port near the impeller end of the stuffing box, and the diverted flow exits the lantern ring at the inner groove closer to the motor end. Generally, two or more packing rings are added on the motor side of the bearing to complete the installation. 
         [0007]    Accordingly, it is an object of the invention to provide an improved bearing with an integral lantern ring to be inserted into a seal cavity of a rotary mechanical device. 
         [0008]    Another object of the invention is to provide an improved bearing with an integral lantern ring with an outer grove at one location along the length of the bearing and an inner or internal groove connected thereto at another location along the length of the bearing. 
         [0009]    Still another object of the invention is to provide an improved bearing for a rotary mechanical device having an integral lantern ring and a bearing outer O-ring for improved isolation of the product being handled by the rotary device. 
         [0010]    Yet another object of the invention is an improved bearing with an integral diverted lantern ring for use with complementary flexible packing rings for use in a shaft sealing system to be inserted into the seal cavity of rotary mechanical devices. 
         [0011]    A further object of the invention is to provide a bearing with an integral lantern ring with an outer lantern ring groove and holes closer to the impeller end of the seal cavity and an inner lantern ring groove and holes closer to the motor end of the seal cavity. 
         [0012]    Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification and claims. 
         [0013]    The invention comprises a product possessing the features, properties, and the relation of components which will be exemplified in the product hereinafter described and the scope of the invention will be indicated in the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    For a fuller understanding of the invention, reference is made to the following description taken in connection with the accompanying drawings, in which: 
           [0015]      FIG. 1  is a partial cross-sectional view of a typical rotary fluid pump with a bearing in accordance with the invention installed in the seal cavity; 
           [0016]      FIG. 2  is an enlarged cross-sectional view of the seal cavity of the pump showing a bearing with diverted lantern ring sealing system in accordance with the invention in place in the seal cavity; 
           [0017]      FIG. 3  is a side elevational view of the bearing with diverted lantern ring of  FIG. 2  prepared in accordance with the invention; 
           [0018]      FIG. 4  is a perspective view of the bearing of  FIG. 3 ; 
           [0019]      FIG. 5  is a cross-sectional view along the line  5 - 5  in  FIG. 3 ; 
           [0020]      FIG. 6  is a cross-sectional view along the line  6 - 6  in  FIG. 3 ; and 
           [0021]      FIG. 7  is a side elevational view of an embodiment of the invention wherein the bearing of  FIG. 2  includes an outer O-ring; 
           [0022]      FIG. 8  is a perspective view of the two sections of the bearing of  FIG. 3 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]      FIG. 1  illustrates a generic form of a centrifugal pump  11  in cross-section mounted on a frame  10 . Pump  11  includes a centrifugal impeller  12  driven by an electric motor  13  that drives a rotary shaft  14  coupled to impeller  12 . Shaft  14  is supported by a bearing housing  16  and rotates to draw fluid in through an impeller inlet  17  and expel the fluid out through a radial impeller outlet  18 . 
         [0024]    Pump  11  includes a housing  19  having an inner bore  21  that defines a seal cavity or stuffing box  22  with shaft  14  passing therethrough as shown in detail in  FIG. 2 . Housing  19  includes an impeller opening  23  through which shaft  14  passes to engage impeller  12  and also includes a flush port  25  at the impeller end of stuffing box  22  for introduction of a flush fluid into stuffing box  22 . Shaft  14  is coupled to impeller  12  by a nut or fastener  24  at the end portion of shaft  14  projecting through impeller  12 . 
         [0025]    Pump  11  operates by drawing a fluid to be pumped into inlet  17 . During pumping, fluid tends to migrate and be forced into seal cavity  22  through opening  23 . A wide variety of seals and venting configurations are available to be placed in seal cavity  22  abutting opening  23  in order to restrict and limit entry of pumped fluid into seal cavity  22 . If fluid enters seal cavity  22  and migrates to bearings  32   a,    32   b,  bearings  32   a,    32   b  will be subject to substantial degradation due to the corrosive action of the pumped fluid. 
         [0026]      FIG. 2  is an enlarged view of seal cavity  22  with a bearing with diverted lantern ring  31  in accordance with the invention in place. The motor end of seal cavity  22  is defined by a gland follower  27  mounted on gland bolts  28  and secured in place by gland nuts  29 . 
         [0027]    As shown in  FIG. 2 , bearing  31  constructed and arranged in accordance with the invention is positioned against the impeller end of seal cavity  22 . A pair of compressible sealing rings  32   a,    32   b  are positioned on the motor side of bearing  31 . These elements are secured within seal cavity  22  by gland follower  27 . Examples of various types of packing rings suitable for use herein are shown in U.S. Pat. No. 5,370,926, No. 4,559,862, No. 4,431,698, No. 4,371,180, and No. 4,298,207, the contents of which are incorporated herein by reference. 
         [0028]    In  FIG. 3 , bearing  31  is shown in a side elevational view. Bearing  31  is custom made for a particular shaft and pump. Bearing  31  is shown in perspective in  FIG. 4 . 
         [0029]    Bearing  31  is a substantially cylindrical rigid member with an outer surface  33  and with an inner bore  34  closely dimensioned to the outer dimension of pump shaft  14  and fits within inner bore  21  of pump housing  19 . Outer surface  33  of bearing  31  is formed with an outer flush fluid groove  36  at the impeller end at the location of flush port  25 . Inner bore  34  of bearing  31  provides a bearing surface for shaft  14  when in position as shown in  FIG. 2 , and this is custom dimensioned for a particular mechanical device. 
         [0030]    Bearing  31  is also formed with an inner flush fluid groove  37  formed in a location closer to the motor end to create a diverted lantern ring. Inner seal fluid groove  37  is formed in a position not adjacent to, that is, not aligned with, the location of outer flush fluid groove  36 . A plurality of flush fluid holes  38  formed in outer bearing flush fluid groove  36  are in fluid communication with flush fluid holes  45  in inner groove  37  through channels  46 . 
         [0031]    In the embodiment illustrated in  FIGS. 1-3 , outer lantern ring groove  36  is closer to the motor end of stuffing box  22 . The purpose of providing the diverted lantern ring with holes  45  closer to the motor end is to redirect the external flush from outer groove  36  to inner groove  37  at the motor end. This increases the throttling characteristic of the close clearance of the bearing surface to the shaft. 
         [0032]    In order to place bearing  31  in position in seal cavity  22 , bearing  31  is split along a centerline  39 , as shown in  FIGS. 5 and 6 . Splitting bearing  31  along a diameter allows bearing  31  to be placed about installed shaft  14  and pushed into position at the impeller end of seal cavity  22 . Generally, at least one or two packing rings  32   a,    32   b  are positioned on the gland side of bearing  31 . 
         [0033]    Bearing  31  split along center line  39  includes a pair of corresponding holes  41  on both halves of split bearing  31  for receiving mounting pins  42  for realignment and reassembly thereof. In this construction, pins  42  insure that when bearing  31  is secured about shaft  14 , outer flush fluid groove  36  and inner groove  37  are properly aligned on both sections. Outer flush fluid groove  36  is positioned to align with flush port  25  formed in housing  19 . 
         [0034]      FIG. 7  illustrates an embodiment of the invention wherein a bearing with diverted lantern ring  51  includes an outer surface  52  with an O-ring  53  groove positioned in seal cavity  22 . An O-ring  54  is positioned in O-ring groove  53  formed on outer surface  52  of bearing  51 . O-ring  54  can be formed of a variety of resilient materials, including perfluoroelastomers or other resilient material compatible with the pumped fluid for providing an additional barrier to isolate the motor end of shaft  14  from fluid entering seal cavity  22 . An O-ring  54  provides an additional obstacle to prevent fluid from entering seal cavity  22 . 
         [0035]    Bearing  31  or  51  is custom made for a particular shaft and pump. Cross-sectional elevational views of the mating faces of bearing  31  before reassembly are shown in  FIGS. 6 and 7 .  FIG. 8  is a perspective of the two sections of an axially split bearing showing four extraction holes  48  at the motor end of the A section of bearing  31 . 
         [0036]    Many types of rotary equipment have the flush port close to the impeller end of the stuffing box. Almost all of these operate with heavy solids, such as mining and foods. Many pumps, such as Weir Slurry Group (Warman Pumps) pumps, GIW (Georgia Iron Works) pumps, Morris Pumps, and Krebs Pumps, and mixers (vertical and horizontal) often times have the port located there. The theory is that in order to keep slurry out of the stuffing box, the best position is at the throat. The shortcoming with this view is that flush pressure and volume are not equalized all the way around the lantern ring before it goes into the process solids. By providing a bearing with a close clearance bearing surface ahead of the exit ports of the lantern ring, the close clearance between shaft and bearing where the flush enters, forces equalization all the way around, before the flush fluid gets to the throat. 
         [0037]    The following Example is set forth by way of illustration to help explain the invention, and is not intended to be limiting in any way. 
       EXAMPLE I 
       [0038]    A bearing with an integral diverted lantern ring in accordance with the invention is prepared as follows. The bearing is of a given length with an A Section that is the extraction side with an inner lantern ring groove and a B Section that is the impeller side and is chamfered with an outer lantern ring groove. 
         [0000]    1. A piece of tube stock of a selected material is cut to a length corresponding to the total length of Sections A and B;
 
2. The piece is then cut into an A Section and a B Section;
 
3. End holes are drilled in the mating end faces of Sections A and B;
 
4. Pins are inserted into the holes in the mating faces to facilitate press-fit reassembly of the Sections A and B;
 
5. The combined Sections A and B are split in half axially.
 
6. The individual sections are milled, drilled and pinned and reassembled for final machining;
 
7. O.D and I.D. are finish turned to a specific diameter;
 
8. An inner groove is formed in Section A, and outer groove is formed in Section B, at predetermined locations;
 
9. Aligned flush holes are drilled in the O.D and I.D groove in each Section A and B to a predetermined depth;
 
10. Flush channels are completed by drilling into mating faces of each section to break through and connect to existing drill holes; and
 
11. Extraction holes are drilled into the motor end of Section A.
 
         [0039]    In this case bearing  31  of  FIG. 3  has outer diameter  33  of 9.172″ and inner diameter  34  of 7.140″ and is 2.963″ in length. The A section with inner groove  37  and extraction holes are cut to 1.482″ in length. Inner groove  37  is cut 0.250″ from the extraction end and 0.625″ wide. The B section outer groove  36  cut 0.375″ from the impeller end to match flush port  25  port the device. Flush holes  44  and  45  are ⅜″ in diameter and flush channels  46  are completed by drilling into the mating faces of each section. 
         [0040]    The dimensions set forth above are representative and not limiting of the invention. The actual dimensions of aspects of bearings to be prepared and installed according to the invention will vary according to the particular application. 
         [0041]    Bearings  31  and  51  are substantially rigid and formed of materials which will not be attacked or destroyed by corrosive fluids being transported by pump  11 . Preferred materials of construction include non-ferrous materials, molybdenum/-carbon or glass filled thermoplastic material, such as polytetrafluoroethylene (PTFE) or other suitable plastic material. Materials are selected that can provide a suitable bearing surface and are resistant to most industrial solutions. Suitable bearing materials are those that provide suitable chemical, temperature, compressive strength, flexural strength and wear characteristics and can be appropriately machined to yield the desired bearing dimensions and tolerances. Such bearing materials include, but are not limited to, polymers, including polyphenylene sulfides, polyimidizoles, polyamideimides, polybenzylimidizoles, PEEK polymers obtained by step-growth polymerization by the dialkylation of bisphenolate salts, PTFE, perfluoroalkoxy, and formulations containing these polymers in a major proportion. 
         [0042]    Packing materials are described in the aforementioned U.S. Pat. No. 4,298,207, No. 4,371,180, No. 4,431,698, No. 4,559,862, and No. 5,370,926, the contents of each of which are incorporated herein by reference in their entirety. More particularly, useful materials include, but are not limited to, mechanically and/or thermally resilient component of graphite tape, expanded graphite foil, graphite fiber, carbon fiber, polybenzimidazole (PBI) fiber, PEK fiber, PEEK fiber, PFA fiber, aromatic polyamide fiber, Inconel or Monel wire, or combinations thereof. In another aspect of the invention, the at least one packing member is a material selected from the group consisting of carbonized yarns, graphitized yarns, exfoliated graphite yarns, ceramic yarns, and glass yarns. Tension or lip seal rings may comprise the same or different components of the same or different components. The packing rings or members may comprise mechanically and/or thermally components, whether individually or by combinations thereof, i.e., corner yarns, resilient core, etc. The designs and materials are chosen to resist packing consolidation. 
         [0043]    Braided packing rings may include fibers of flax, jute, asbestos, or a synthetic material, such as polytetrafluoroethylene, which fibers are formed into yarns or strands and which are braided together about core strands. The result is typically a packing having a square cross-section and herringbone weave pattern extending in an axial direction along the packing Typical packing members are illustrated in U.S. Pat. No. 3,646,846, incorporated herein by reference. 
         [0044]    In order to place bearing  31  in position in seal cavity  22 , bearing  31  is preferably split along a centerline  39 . Splitting bearing  31  along a diameter allows bearing  31  to be placed about installed shaft  14  and pushed into position at the impeller end of seal cavity  22 . Generally, at least one or two packing rings  32   a,    32   b  are positioned on the gland side of bearing  31 . 
         [0045]    Bearing  31  split along center line  39  includes a pair of corresponding holes  42  on both halves of split bearing  31  for receiving mounting pins  42  for realignment and reassembly of bearing  31 . In this construction, pins  42  insure that when bearing  31  is secured about shaft  14 , outer seal water groove  36  and inner groove  37  are properly aligned on both sections. Outer seal water groove  36  is dimensioned and positioned to align with a flush port  25  formed in housing  19 . 
         [0046]    It can readily be seen that the bearing with integral diverted lantern rings as part of a cylindrical seal and seal system constructed in accordance with the invention can be easily installed in a conventional rotary impeller pump with pins to guarantee alignment of the seal upon installation. This configuration allows seal fluid to contact the shaft closer to the motor end. Generally, two packing rings or more are added to complete installation of an effective sealing system. When in place, the bearing will support the impeller end of the pump shaft, providing an additional bearing surface to aid in eliminating the whip commonly found in pump and other rotary equipment shafts. Since the clearance between the pump shaft and the bearing is relatively small, flush fluid entering the lantern ring groove would be considerably throttled, thereby minimizing the quantity of seal water flushing and lubricating the bearing and finally entering into and diluting the product being pumped. 
         [0047]    It will thus be seen that the object set forth above, among those made apparent from the preceding description are efficiently attained and, since certain changes may be made in the device set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
         [0048]    It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention, which, as a matter of language, may be said to fall there between.