Patent Publication Number: US-9421550-B2

Title: Vertical support member for intermediate yokes on comminutor cutter shafts

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Apparatuses and methods consistent with the present invention relate to comminutors for treating solid material in a liquid waste stream containing solid waste. 
     2. Description of the Related Art 
     By definition, comminution is the reduction of particle size of solid waste material to minute particles. The comminution or the reduction of particle size of solid waste material into fine particles is performed by feeding solid waste material into the interface of counter-rotating intermeshed cutting elements while entrained in a liquid. These cutting elements may be in the form of a disk and may have projecting cutting teeth which overlap during rotation. The solids are then sheared and shredded by the action of the adjacent rotating elements, i.e., comminutors. 
     However, the cutter shafts of a dual shafted comminutor assembly tend to deflect away from each other when macerating heavy solids. If this deflection becomes excessive, the solids may not be completely ground. The deflection may also induce shaft failure, and if excessive enough, may damage adjacent components by direct contact. 
     In the related art as shown in  FIG. 1 , the counter-rotating cutter stacks  44  and  46  comprise an alternating sequence of cutting elements  48  and spacers  50  fitted over a shaft  5 ,  68 . The overlap and counter-rotation occurring on zone  52  shreds the material as it passed through the cutter elements. The deflection of the cutter shafts may be limited by installing one or more floating intermediate shaft supports  10  along the cutter stacks  44 ,  46  which are held in place by the compression of the cutter stack elements allowing them to float as they operate. The downside to these intermediate shaft supports is that they wear unevenly due to side and axial loads that occur from macerating forces and gravity. The result is premature wear that typically requires part replacement before the cutter stack requires replacing. Over time, improvements made to the floating design include lubrication ports and improved bushing materials, but these improvements have only resulted in incremental improvements in wear life. Thus, there is a need to improve the wear characteristics of these floating intermediate shaft supports  10 . 
     As shown in  FIGS. 2A-3A , each intermediate shaft support  10 , also known as a yoke, is a passive device used to prevent the deflection of dual-shafted comminutor cutter stacks  44 ,  46  while macerating. It is comprised of two housings  20  or brackets fastened together and contain four friction reducing bushings  30  and two rotating inner races  40 . Two bushings  30  are press-fit into each of the two machined bores of each housing  20 . The two inner races  40  are then installed in each bushing  30  of one housing  20  and are then enclosed by the second housing  20 , which are fastened using bolts  60 , for example, to create a contained intermediate shaft support  10 . Each inner race  40  has a close clearance fit to the bushings  30  which allows the races to rotate freely. Each inner race  40  may have a profile so as to engage and rotate with the shape of the cutter shafts  5 , 68 . In this embodiment, the shape of the cutter shafts is hexagonal. The inner races may have a hex-shaped profile as shown in  FIG. 3A . 
     The inner races  40  operate similar to bearing inner races, except that the mode of rotation is by the fixed bushings as opposed to rolling bearing balls or rollers. One or more intermediate shaft supports  10  are installed on the two cutter shafts  5 ,  68  at strategic locations relative to the cutters and spacers, with each support yoke taking the place of approximately four cutters and spacers on each shaft. The brackets have lubrication ports to allow for external addition of lubrication once the components are assembled and installed. 
     While these intermediate shaft supports have conventionally been floating, in one application where the cutters are sandwiched between two adjacent walls, the intermediate shaft support  10  was formed with side wall portions  11  that were bolted to the two adjacent walls for the purposes of maintaining the position of the walls as shown in  FIGS. 3B-3D . 
       FIGS. 9 and 10  shows a comminutor in the related art having a intermediate shaft support  10  installed on the cutter stacks  46  that are disposed between two rotating screens  48 . As is evident from these figures, removal and maintenance of the intermediate shaft support  10  requires substantial time an effort as the comminutor must be disassembled to access the intermediate shaft support. 
     However, these intermediate shaft supports are prone to wear. As such, the comminutor assembly must be periodically taken out of service for maintenance. This maintenance may include merely shutting down the comminutor to lubricate the shaft support, but eventually, the comminutor assembly, including the two cutter shafts, must be disassembled to rebuild or replace the intermediate shaft supports. 
     SUMMARY OF THE INVENTION 
     Exemplary embodiments of the present invention overcome the above disadvantages and other disadvantages not described above. Also, the present invention is not required to overcome the disadvantages described above, and an exemplary embodiment of the present invention may not overcome any of the problems described above. 
     According to one aspect of the invention, a comminutor is provided for reducing the particle size of solid waste. The comminutor comprises two shafts each fitted with a cutting elements. A top portion of each of shaft is rotatably mounted to a top housing and a bottom portion of each shaft is rotatably mounted to a bottom housing. A first shaft support is disposed between the top portion and the bottom portion for rotatably supporting each of the shafts. A vertical support member is attached to the top housing and the bottom housing, the first shaft support being coupled to the vertical support member. 
     According to another aspect, the comminutor further comprises a second shaft support disposed between the top portion and the bottom portion for rotatably supporting each of the shafts, the second shaft support is spaced apart from the first shaft support. 
     According to another aspect, the vertical support shaft comprises an internal channel. Also included is a lubrication line extending from the top housing to the first shaft support. A least a portion of the lubrication line lies within the internal channel. One end of the lubrication line is connected to the first shaft support and the second end of the lubrication line is fitted with a fitting configured to receive lubrication. 
     According to another aspect, the first shaft support is coupled to the vertical support member using an adjustable friction fitting. The vertical support member has a cross-section having a U-shape or an I-shape and the vertical support member is disposed downstream of the two shafts with respect to the direction of waste flow through the comminutor. 
     According to another aspect, a vertical support member is provided. The vertical support member comprises a beam member having an internal passage, a top and a bottom; an adjustable bracket disposed between the top and the bottom of the beam member; a fitting for adjustably fixing the adjustable bracket to the beam member. 
     According to another aspect, the vertical support member comprises a top bracket fixed to a top of the beam member and a bottom bracket fixed to the bottom of the beam member. The vertical support member may also comprise a lubrication line extending from the top of the beam member to the adjustable bracket. 
     According to another aspect, a method for assembling a vertical support member is provided. The method comprises preparing a top housing and bottom housing of a comminutor for attachment to a top and bottom of a vertical support member, respectively; securing the vertical support member to the top and the bottom of the top housing and the bottom housing; preparing an intermediate shaft support for attachment to an adjustable bracket of the support member; securing the intermediate shaft support to the adjustable bracket; running a lubrication line from the top of the vertical support member to the adjustable bracket and securing the lubrication line to the vertical support member; and connecting the lubrication line to the intermediate shaft support. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects of the present invention will be more apparent by describing certain exemplary embodiments of the present invention with reference to the accompanying drawings, in which: 
         FIG. 1  shows a comminutor in the prior art which does not include a vertical support member. 
         FIGS. 2A and 2B  show a cross-sectional view and a perspective view of a shaft support in the prior art. 
         FIG. 3A  shows an exploded view of the shaft support in the prior art. 
         FIGS. 3B-3D  shows an intermediate shaft support in the prior art. 
         FIGS. 4A and 4B  show a comminutor in accord with an embodiment having a vertical support member in accord with an embodiment of the present invention. 
         FIG. 5  shows a view facing upstream of a just vertical support member attached to a shaft support according to an embodiment. 
         FIGS. 6A and 6B  shows a cross-sectional view and a top view of a shaft support mounted to a vertical support member. 
         FIG. 7  shows a perspective view of a shaft support mounted to a vertical support member. 
         FIG. 8  shows two shaft supports mounted to a single vertical support member in accord with another embodiment. 
         FIGS. 9 and 10  show a comminutor in the prior art that does not include support for the intermediate support member. 
         FIGS. 11 and 12  show a comminutor fitted with a vertical support member in accord with the present invention. 
         FIG. 13  is a flow chart depicting a method of fitting a comminutor with a vertical support member. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Certain exemplary embodiments of the present invention will now be described in greater detail with reference to the accompanying drawings. 
     In the following description, the same drawing reference numerals are used for the same elements even in different drawings. The subject matter described in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of the invention. Thus, it is apparent that the present invention can be carried out without those specifically described matters. 
     The foregoing exemplary embodiments are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of methods and apparatuses. Also, the description of the exemplary embodiments of the present invention is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art. 
     As illustrated in  FIGS. 4A and 4B , to improve the wear characteristics of the intermediate shaft support  10 , a vertical support member  100  is provided between a top and bottom housing of at the discharge side of the comminutor. The vertical support member  100  is configured to support one or more intermediate shaft supports  10 . 
     In this embodiment, as shown in  FIGS. 5-8 , the vertical support member  100  is made from sheet metal formed into a structural profile, e.g., a U-shape or I beam shape, which gives it high rigidity and allows for an internal protected channel  90  (inside of the U). However, the support member  100  may be formed in other shapes that provide structural rigidity as well as an internal channel  90 . The internal channel  90  provides protection for lubrication line(s)  110 , which provide the ability to lubricate the intermediate shaft supports  10  during operation of the comminutor. 
     The vertical support member  100  may be fastened to the top  70  and bottom  80  housings of the comminutor. By fastening the vertical support member  100  in this manner, the support is stably secured by the same members that support the cutter stacks  44 ,  46 . 
     In this embodiment, the vertical support member  100  is mounted in close proximity to the cutters  44 ,  46  and shaft supports  10  via adjustable mounting brackets  160  on the discharge side of the comminutor by attachment to both the top housing  70  and the bottom housing  80 .  FIG. 4  shows the direction of the waste flow. An additional mounting bracket  150  affixes each shaft support  10  assembly to the vertical support member  100  with an infinitely adjustable, positive engagement friction mechanism that allows each yoke support assembly to mount anywhere along the cutter stack. However, the shaft supports  10  may be mounted using a bolt assembly or some other fixing member. 
     As shown in  FIGS. 6A-6B , the mounting bracket  150  in this embodiment is comprised of an internal collar  152  that is secured using a bolt  153  to frictionally fix the intermediate shaft support  10  to the vertical support member  100 . 
     Once the support shafts  10  are attached using the mounting brackets  150 , a first end  130  of each of the two tubular lubrication lines  110  are connected to each shaft support  10  on the comminutor discharge side near the location of the rotating races. The lubrication lines  110  are then routed into the internal channel  90  and extend upward through the internal channel  90  to the top mounting bracket  160  to terminate at a first end  130 . 
     In this embodiment, the second ends  140  of the lubrication lines  110  are joined into a single lubrication line at a tee  151  before extending upward through the channel. Thus, only one lubrication lines extends to the first end  130  which terminates with a lubrication fitting that contains a ball-check valve. Additional distance may be achieved with a longer lubrication run for each shaft support  10 . Optionally, the system may be equipped without tubular lubrication lines in which each support bracket is terminated with two ball-check valve lubrication fittings mounted locally (known as local lubrication type). A second optional configuration (known as automatic lubrication type) uses the tubular lubrication lines terminating at the top of the vertical support member as previously mentioned. However, instead of terminating with ball-check valve fittings, each lubrication line is connected to a remotely mounted powered automatic lubrication device which delivers lubrication to each support yoke at controlled predetermined time intervals. 
     As shown in  FIG. 8 , multiple shaft supports  10  may be placed on a single vertical support member  100 . Here, a single lubrication line may be branched to supply each shaft support  10 . Alternatively, each shaft support  10  may have its own lubrication line extending to the top of the vertical support member  100 . 
       FIGS. 11 and 12  show a vertical support member  100  supporting an intermediate shaft support  10  in accord with another embodiment. The vertical shaft support is positioned in the downstream flow direction with respect to the cutter stacks  46 . It is mounted to the top and bottom housings  70 ,  80  using a bracket  160 . The intermediate shaft support  10  is then attached to the vertical support member  100  using an infinitely adjustable bracket  150 . The lubrication lines  110  are connected to each side of the intermediate shaft support  10  and then routed to the top of the vertical support member  100 . Each lubrication line  110  may be connected together into a single line  110  for extending to the top of the vertical support member  100 . As such, lubrication may be applied to the intermediate shaft support  10  during operation of the comminutor. Additionally, because the lubrication lines  110  can be accessed at all time, lubrication can be applied using an automated system either intermittently or continuously. 
       FIG. 13  depicts a flow diagram that shows a method of retrofitting a comminutor with a vertical shaft support  100 . First, holes are added to the intermediate shaft support so that the support can be secured to the bracket  150  which is mounted on the vertical support member (S 101 ). The top and bottom housings are also fitted with holes so that the vertical support member can be secured to these portions (S 101 ). Next, the vertical support member  100  is fixed to the top housing and the bottom housing (S 102 ). Then, the intermediate shaft support  10  is attached to the vertical support member  100  using an infinitely adjustable bracket  150  (S 102 ). After securing the vertical support member  100  in this manner, lubrication lines  110  are run from the top of the comminutor to each intermediate shaft support  10  (S 103 ). The lubrication lines are then secured to the vertical support member  100  (S 104 ). Lastly, the top of the lubrication lines  110  are then either fitted with zerk fittings or connected to an automated lubrication system. 
     While this invention has been particularly shown and described with reference to exemplary embodiments thereof, the above description should be considered in as illustrations of the exemplary embodiments only and are not for purposes of limitation. Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention. Additionally, the features described in the various embodiments are not exclusive in that a feature of one embodiment may be incorporated into another embodiment.