Abstract:
Disclosed herein is an apparatus for an immersible pump. The apparatus can include a shaft for communicating with a motor. The shaft includes a first region having a first diameter, a second region having a second diameter that is less than the first diameter, and a tapering region between the two regions. A sleeve can be provided to receive the shaft. A sealing device includes a receiving area in which the tapering region is at least partially positionable to form a seal, and an abutment that is configured to form a seal with the sleeve and that is responsive to a force directed from the sleeve to enhance the seal with the tapering region. In some embodiments, the sealing device is provided with a circumferential outer wall for centering the sleeve about the shaft and/or for aligning the force with the abutment.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to a shaft sealing device, and, more specifically, to a sealing device that is compressible between a shaft and a shaft sleeve for restricting fluidic access between the shaft and the shaft sleeve. 
       BACKGROUND OF THE INVENTION 
       [0002]    Immersible pumps known in the art are utilized to pump fluid from a fluid source. Often, the fluid being pumped contains corrosive liquid chemicals. At least for reasons due to the corrosive nature of the fluid, it is desirous to keep the fluid away from metal components of the immersible pump, such as the shaft, for example. To achieve this, a non-metal sleeve is provided to cover the shaft and thus protect it from contacting the corrosive fluid. However, a small space remains between the shaft and the sleeve where fluid may enter. The prior art includes the use of an o-ring in an effort to restrict fluid entry. For example, reference is made to the prior art pump  500  of  FIG. 11 . The prior art pump  500  includes a motor  502 , a housing  504 , a shaft  506 , a sleeve  508 , and an impeller  510 . The shaft  506  includes a motor engaging component  514 , an enlarged hollow attachment component  516 , and an extension component  518 . An o-ring  512  and the shaft sleeve  508  are placed over the extension component  518  until the o-ring  512  abuts the enlarged attachment component  516 , and the impeller  510  is tightened to force the sleeve  508  to compress the o-ring  512  against the enlarged attachment component  516 . The o-ring  512  inhibits the entry of fluid into space between the shaft  506  and the sleeve  508 . What is desirable in the art, however, is a means for providing an enhanced seal. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention overcomes the disadvantages and shortcomings of the prior art by providing a sealing device for an immersible pump and methods of manufacture thereof. 
         [0004]    In some embodiments, an apparatus is provided that includes a shaft for communicating with a motor, wherein the shaft includes a first region having a first diameter, a second region having a second diameter that is less than (e.g., skinnier than) the first diameter, and a tapering region between the two regions. The apparatus may also include a sleeve having a bore configured to receive the shaft, and a sealing device. The sealing device can include a receiving area configured so that the tapering region of the shaft is positionable at least partially therein to form a seal therewith, and can further include an abutment that is configured to form a seal with the sleeve and that is responsive to a force directed from the sleeve to enhance the seal with the tapering region. The sealing device can have a circumferential outer wall positionable proximal the sleeve. The circumferential outer wall is preferably provided as a cylindrical wall, though it can be provided as a pseudo-cylindrical wall (e.g., rectilinear, octagonal, etc.) with geometry complementary to the shaft and sleeve. In some embodiments, the abutment may be formed by an annular ring, positioned between the receiving area and the circumferential outer wall, and having a radially-extending shoulder. In some embodiments, the circumferential outer wall can be positionable with a gap between the second region and the sleeve so as to direct a load on the sealing device from the force to said shoulder. In some embodiments, the circumferential outer wall of the sealing device can aid in centering the sleeve about the shaft and/or aligning the force against the abutment. In some embodiments, the shaft has a first end positionable proximal the sealing device and a second end opposite the first end, and the sleeve has a first end positionable proximal the sealing device and a second end opposite the first end. An impeller can be provided that may be securable to the second end of the shaft against the second end of the sleeve. The impeller may be securable to the second end of the shaft so as to force the second end of the sleeve toward the abutment, or the impeller may be threadably engageable with the second end of the shaft so as to force the sleeve in a direction toward the abutment. Some embodiments of the immersible pump are provided at least partially disassembled in the form of a kit. 
         [0005]    In some embodiments, an apparatus for use with an immersible pump includes a sealing device including a first sealing means for forming a seal with a tapering region of a shaft communicable with a motor, and a second sealing means for forming a seal with a sleeve configured to have the shaft extend therethrough and for enhancing the seal of the first sealing means in response to a force directed at least in part from the sleeve. 
         [0006]    In some embodiments, a method is provided for assembling a submersible pump wherein a shaft is provided having a first region having a first diameter, a second region having a second diameter less than the first diameter, and a tapering region therebetween. A sleeve with a first end and a second end opposite the first end, and a sealing device including a receiving area configured to have the tapering region at least partially positioned therein and an abutment, are also provided. The shaft is inserted into the receiving area of the sealing device and into the first end of the sleeve. The first end of the sleeve is caused to direct a force toward the abutment so as to seal the receiving area with the tapering region at least partially positioned therein and at least partially seal the sleeve. In some embodiments, causing the first end of the sleeve to direct the force toward the abutment can comprise forcing the second end of the sleeve in a direction toward the abutment. In some embodiments, forcing the second end of the sleeve in the direction toward the abutment can comprise forcing the second end of the sleeve in the direction toward the abutment by attaching an impeller to the shaft. In some embodiments, attaching an impeller to the shaft can comprise threading the impeller to an end of the shaft proximal the second end of the sleeve. In some embodiments, the sealing device can be provided to include a circumferential outer wall. In such embodiments, the shaft can be inserted into the circumferential outer wall and the circumferential outer wall can be positioned between the shaft and the sleeve to center the sleeve about the shaft and/or to align the force with the abutment. 
         [0007]    Additional features, functions and benefits of the disclosed sealing device and methods and apparatus in connection therewith will be apparent from the detailed description which follows, particularly when read in conjunction with the accompanying figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    For a more complete understanding of the present invention, reference is made to the following detailed description of an exemplary embodiment considered in conjunction with the accompanying drawings, in which: 
           [0009]      FIG. 1  is a perspective view of an immersible pump constructed in accordance with an embodiment of the present invention, the immersible pump being shown to include a motor, an impeller housing, and an end cap; 
           [0010]      FIG. 2  is a perspective view of the immersible pump of  FIG. 1  with the impeller housing having been removed to show a shaft, a shaft sleeve, an impeller, and a sealing device of the immersible pump; 
           [0011]      FIG. 3  is a sectional view of the immersible pump of  FIGS. 1 and 2  taken along section line  3 - 3  of  FIG. 1 ; 
           [0012]      FIG. 4  is a sectional view of the end cap and impeller housing of  FIGS. 1-3  showing an enlargement of area  4  of  FIG. 3 ; 
           [0013]      FIG. 5  is a sectional view of the impeller, the impeller housing, the shaft sleeve, and the shaft of  FIGS. 1-3  showing an enlargement of area  5  of  FIG. 3 ; 
           [0014]      FIG. 6  is a perspective view of the shaft, the shaft sleeve, and the sealing device of  FIGS. 1-3  showing an enlargement of area  6  of  FIG. 2 ; 
           [0015]      FIG. 7  is a sectional view of the shaft, the shaft sleeve, and the sealing device of  FIGS. 1-3  taken along section line  7 - 7  of  FIG. 6 ; 
           [0016]      FIG. 8  is a top plan view of the sealing device of  FIGS. 1-7 ; 
           [0017]      FIG. 9  is a sectional view of the sealing device of  FIGS. 1-8  taken along section line  9 - 9  of  FIG. 8 ; 
           [0018]      FIG. 10  is an elevational view of the sealing device of  FIGS. 1-9 ; and 
           [0019]      FIG. 11  is a partially-sectioned view of a prior art pump. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    Referring to  FIGS. 1-3 , an immersible pump  10  is shown constructed in accordance with an exemplary embodiment of the present invention. The use of the word immersible should not be construed as requiring the reference device to be fully submerged in fluid. The immersible pump  10  includes a motor  12 , an impeller housing  14 , an end cap  16 , a shaft  18 , a shaft sleeve  20 , an impeller  22 , and a sealing device  24 , each of which will be discussed with further detail below. 
         [0021]    Referring to  FIG. 3 , the immersible pump  10  includes the impeller housing  14 . The impeller housing  14  can be generally monolithic in form and includes an end plate  26 , a first portion  28 , a second portion  30 , and a division wall  32  separating the first portion  28  and the second portion  30 . The first portion  28  generally forms a first shaft chamber  34  and a second shaft chamber  36  for substantially housing a portion of the shaft  18 , the shaft sleeve  20 , and the sealing device  24 . Extending through a wall of the first portion  28  are an access hole  38  and a drain hole  40 , which will be discussed in greater detail below. The division wall  32  is generally provided between the first portion  28  and the second portion  30 , and includes a through-hole  42  which permits the shaft  18  and the shaft sleeve  20  to extend from the first portion  28  to the second portion  30 . The second portion  30  generally includes an outlet  44  formed on the exterior and extends tangentially therefrom. The outlet  44  permits fluid to flow outward from the second portion  30 . Optionally, a hose  46  or other conduit such as a pipe may be connected to the outlet  44  for facilitating the removal of fluid. The second portion  30  further forms an impeller chamber  48  which substantially houses the impeller  22 , the end cap  16 , a portion of the shaft  18  and a portion of the shaft sleeve  20 . The impeller chamber  48  is substantially divided from the second shaft chamber  36  by the division wall  32 . 
         [0022]    Referring to  FIGS. 3-4 , the second portion  30  further defines an opening  50 , and includes a counter bore  52  and a circumferential recess  54 . The counter bore  52  forms a radial shoulder  56 . Housed in the second portion  30  is the end cap  16 , which includes a tubular region  58 , an annular flange  60  and an L-shaped extension  62 . The tubular region  58  defines an inlet  64  and an outlet  66 . The annular flange  60  extends radially outward from the tubular region  58  and includes an extension  68  extending from an intermediate point along the annular flange  60 . The annular flange  60  further includes an L-shaped extension  62  which extends from the intermediate point along the annular flange  60 . The L-shaped extension  62  cooperates with the extension  68  to form a chamber  70  which houses an o-ring  72  that seals the end cap  16  against the impeller housing  14 . When the end cap  16  is housed in the second portion  30  of the housing  14 , the extension  68  engages the radial shoulder  56  of the second portion  30 . A snap ring  74  can be snapped into the circumferential recess  54  of the second portion to secure the end cap  16  within the second portion  30 . The inlet  64  and the outlet  66  allow fluid to flow through the end cap  16  and into the impeller chamber  48  so that the impeller  22  can act on the fluid. 
         [0023]    Referring to  FIGS. 3 and 5 , the impeller  22  includes a first casing  76  and a second casing  78  integrally secured to each other at a junction  80 , which may be a friction weld, ultrasonic weld, or any other type of weld as known in the art, for example. Further, the first casing  76  and the second casing  78  may be secured to each other by cement or mechanical fastening. The first casing  76  includes an exterior cylindrical wall  84 , an interior cylindrical region  86 , a rear wall  88 , and rear flutes  90 . The interior cylindrical region  86  includes a bore  92 , a first counter bore  94 , a second counter bore  96 , and a third counter bore  98 . The bore  92  extends through the entirety of the interior cylindrical region  86  and forms an opening  100  that provides access to the interior of the impeller  22 . The first counter bore  94  provides a space for an internally threaded insert  102  to be secured, and further creates a first shoulder  104  at which the internally threaded insert  102  is abuttingly seated. The threaded insert  102  can be a threaded cap, for example. The internally threaded insert  102 , which is preferably formed of metal, can be secured within the first counter bore  94  by welding, including friction welding, ultrasonic welding, or other welding processes known in the art. In some embodiments, the threaded insert  102  can be secured in the first counter bore  94  by being molded in place or overmolded by injection molded thermoplastic. In some embodiments, the internal threads can be formed directly in the first counter bore  94 , and the threaded insert  102  is not required. The second counter bore  96  extends partially through the interior cylindrical region  86  and forms a second shoulder  106 . The third counter bore  98  extends partially through the interior cylindrical region  86  and forms an annular wall  108  and a third shoulder  110 . Shoulders  106  and  110  are proximal the shaft  18  and the shaft sleeve  20 , which are further discussed below. The second casing  78  includes a cylindrical wall  112 , a front wall  114 , and front flutes  116 . The front flutes  116  are attached to or formed with the exterior of the front wall  114 . 
         [0024]    Referring to  FIGS. 3, and 5-7 , the impeller  22  is preferably engaged with the shaft  18  and the shaft sleeve  20 . The shaft  18  is preferably cylindrical, extends along axis A, and includes a first end  118  and a second end  120 . The geometry of the shaft  18  is not limited to a cylindrical geometry, but may be any one of a plurality of geometries including but not limited to rectilinear, octagonal, or any other contemplated geometry (and the internal negative space of the sleeve  20  and sealing device  24  is preferably made complementary thereto). The shaft  18  is preferably a motor shaft, but may be any type of shaft and is not limited to having an immediate mechanical connection to a motor—there can be a linkage, for example, between the shaft  18  and the motor to which it is in mechanical communication with. The first end  118  can be attached to a motor  12 , such that the motor rotates the shaft  18  about axis A, or it can be in communication with the motor  12 , such that the motor otherwise induces rotation of the shaft  18 . The shaft  18  includes near the first end  118  thereof, a first region  122  having a first diameter D1 that transitions to a second region  124  having a second diameter D2 that is less than D1. In some embodiments, the second region  124  may extend to the second end  120 . A tapering region  126  extends between the first region  122  and the second region  124  and includes a sloped wall  128 . The sloped wall  128  of the tapering region  126  transitions the first diameter D1 to the second diameter D2. The second end  120  extends to an end wall  130  provided with a threaded extension  132  extending coaxially therefrom. The threaded extension  132  threadably engages the internally threaded insert  102  to form a connection between the shaft  18  and the impeller  22 . 
         [0025]    During assembly, the impeller  22 , by way of the internally threaded insert  102 , can be rotated clockwise to threadably attach to the threaded extension  132  via a right-hand thread. When the impeller  22  is fully threaded onto the threaded extension  132 , the end wall  130  abuts the second shoulder  106  of the impeller  22 . In some embodiments, the motor  12  generally rotates the shaft  18  in a counter-clockwise direction and the counter-clockwise rotation acts to further tighten the impeller  22 , retaining its engagement with the shaft  18 . 
         [0026]    The shaft sleeve  20  includes an elongated body  134  having a first end  136 , a second end  138 , a bore  140  extending through the ends  136 ,  138 , and a counter bore  142  which defines a shoulder  144 . The shaft sleeve  20  geometry complements that of the shaft  18 . The second end  138  of the shaft sleeve  20  may be attached to the impeller  22 . For example, the second end  138  may be inserted into the third counter bore  98  of the impeller  22  so that it abuts the third shoulder  110 . The shaft sleeve second end  138  includes a chamfer  137  at the tip to facilitate insertion into the third counter bore  98  of the impeller. The shaft sleeve second end  138  can have a reduced diameter area  139  that is machined to have a diameter just greater than that of the inner diameter of the impeller annular wall  108 , which is compressed when received within the impeller annular wall  108 . The second end  138  can then be connected to the first casing  76  of the impeller  22  by a friction weld, ultrasonic weld, or other welding technique or solvent cementing known in the art. Such a connection results in a fluid tight seal and permanent connection between the shaft sleeve  20  and the impeller  22 . 
         [0027]    The impeller housing  14 , end cap  16 , shaft sleeve  20 , impeller  22 , and internally threaded insert  102  may all be constructed of plastic or thermoplastic such as chlorinated polyvinyl chloride (CPVC), polyvinyl chloride (PVC), polypropylene, or other suitable material. Further, these components may be manufactured by any molding or extruding process known in the art. Internally threaded insert  102  may also be a cap constructed from brass, stainless steel, or other metals that can be overmolded into the thermoplastic impeller housing. 
         [0028]    Referring to  FIGS. 2, 3, and 6-10 , a sealing device  24  is positioned between the shaft  18  and the shaft sleeve  20  so as to create a fluid tight seal inhibiting the flow of fluid into the space, if any, between the shaft  18  and the shaft sleeve  20 . In preferable embodiments, the sealing device  24  is generally monolithic, e.g., integrally formed. The sealing device  24  includes a first sealing means, e.g., shaft receiving area  150 , for forming a seal with a tapering region of the shaft  18 , a second sealing means, e.g., shoulder  160 , for forming a seal with the shaft sleeve  20  and for enhancing the seal of the first sealing means in response to a force F directed at least in part from the sleeve  20 . A circumferential outer wall  146  may be provided for centering the shaft sleeve  20  about the shaft  18  and/or for aligning the force F with the shoulder  160 , for example. 
         [0029]    The first sealing means can be provided as the shaft receiving area  150 , for example. The shaft receiving area  150  includes an inner surface  162 . 
         [0030]    The second sealing means can be provided as an abutment, which can be of various structures, one such example structure being the annular ring  148  having the shoulder  160 . The second sealing means should be configured to allow the shaft  18  to extend therethrough. The diameter of the shoulder  160  is preferably greater than the diameter of the circumferential outer wall  146 . 
         [0031]    The circumferential outer wall  146  can be configured to have the shaft  18  extend therethrough. In some embodiments, the circumferential outer wall  146  is preferably a cylindrical wall. The circumferential outer wall  146  includes an outer circumferential surface  154 , an inner circumferential surface  156 , and an end surface  158 . 
         [0032]    The circumferential outer wall  146 , annular ring  148 , and shaft receiving area  150  define an opening  152  that accommodates the shaft  18 . The geometry of the sealing device  24  is not limited to a cylindrical geometry, but may be any one of a plurality of geometries including but not limited to rectilinear, octagonal, or any other suitable geometry. Importantly, the geometry of the sealing device  24  is preferably complementary of that of the shaft  18  and the shaft sleeve  20  so as to effectuate a proper seal therewith. 
         [0033]    The sealing device  24  is designed such that the inner diameter of the inner circumferential surface  156  is slightly greater than the second diameter D2 of the shaft  18 , and the diameter of the outer circumferential surface  154  is slightly less than the inner diameter of the counter bore  142  of the shaft sleeve  20 . The angle of the inner surface  162  of the shaft receiving area  150  is to complement the angle of the sloped wall  128  of the tapering region  126  of the shaft  18  to effect a seal. For example, the inner surface  162  may be at an angle of fifteen degrees (15°) relative to axis A. This relationship facilitates having the shaft  18  inserted through the sealing device  24  and into the shaft sleeve  20 , while the sealing device  24  is inserted into the shaft sleeve  20 . The angle of the seal taper, e.g., the angle of inner surface  162 , can be different than the angle of the shaft taper, the angle of the sloped wall  128 . For example, an angle of the sloped wall  128  of the tapering region  126  of the shaft  18  relative to axis A (e.g., twenty-five degrees (25°)) can be greater than an angle of the inner surface  162  of the receiving area  150  of the sealing device  24  relative to axis A (e.g., twenty degrees)(20°) to force greater outward deflection of the inner surface  162  and the receiving area  150  generally. 
         [0034]    As shown in  FIG. 7 , the combination of the shaft  18 , the sealing device  24 , and the shaft sleeve  20  form an assembly where the sealing device  24  is sandwiched between the shaft  18  and the shaft sleeve  20 . In this example arrangement, the inner circumferential surface  156  of the sealing device  24  forms a slip fit with the surface of the second region  124  of the shaft  18 , while the outer circumferential surface  154  of the circumferential outer wall  146  of the sealing device  24  forms an interference fit with the inner surface of the shaft sleeve counter bore  142 . This interaction acts to center the first end  136  of the shaft sleeve  20  around the shaft  18 . This centering acts to retain the shaft  18 , the impeller  22 , and the shaft sleeve  20  in a concentric position with each other. Further, the first end  136  of the shaft sleeve  20  engages the annular ring engagement shoulder  160  such that forcing the shaft sleeve  20  over the shaft  18  applies the force F to drive the sealing device  24  toward the first region  122  of the shaft  18  and forces the shaft receiving area inner surface  162  to engage the tapering region sloped wall  128 . When these components are engaged, a gap  164  is preferably formed between the end surface  158  of the sealing device  24  and the shoulder  144  of the shaft sleeve  20 . As can been seen in  FIG. 7 , the shaft sleeve counter bore  142  has a length of L1 from the annular ring  148  to the shoulder  144 , the sealing device circumferential wall  146  has a length of L2 from the annular ring  148 , while the gap  164  has a length of L3, where the relationship is L3=L1−L2. The gap  164  is provided so that the force F applied to the sealing device  24  causes the load to be focused on the shoulder  160  of the annular ring  148 . Also, the gap  164  accommodates any deformation that may occur in the sealing device  24  due to the shaft sleeve  20  driving the sealing device  24  into the tapering region  126  of the shaft  18 . 
         [0035]    The sealing device  24  may be constructed of a thermoplastic such as polytetrafluoroethylene (PTFE), also known as Teflon™, or any other thermoplastic elastomer including high-molecular-weight thermoplastics. The sealing device  24  may be manufactured by molding, injection molding, machining, or any other suitable process known in the art. The sealing device  24 , in particular the receiving area  150  thereof, is deformable, e.g., resiliently flexible. As the receiving area  150  is forced toward the first region  122 , the receiving area  150  is configured to slightly enlarge, e.g., slightly deform, to have a greater portion of the tapering region  126  positioned therein. 
         [0036]    An example method for assembling the immersible pump  10  of  FIGS. 1-10  shall now be described with further detail. In some embodiments, the impeller housing  14  is first assembled over the shaft  18 , and the end plate  26  is secured to the motor  12 . In some embodiments, the shaft  18  can be inserted through the sealing device  24  prior to the attachment of the impeller housing  14 . 
         [0037]    The impeller  22  is constructed by welding, overmolding, or thermally press fitting the internally threaded insert  102  to the first casing  76  of the impeller  22  at the first counter bore  94 . The first casing  76  and the second casing  78  are then welded or solvent cemented together at junction  80 . The second end  138  of the shaft sleeve  20  is inserted into the third counter bore  98  of the impeller  22  so that the end engages the third shoulder  110 . The shaft sleeve second end  138  is then welded to the annular wall  108  so as to form a permanent fluid tight engagement. 
         [0038]    The shaft  18  is then inserted into the first sealing means  150  of the sealing device  24  and through the opening  152 . Next, the shaft  18  is inserted into the shaft sleeve bore  140  such that the shaft sleeve  20  engages the sealing device  24  and drives the sealing device  24  toward the shaft tapering region  126 . As the shaft sleeve  20  and the impeller  22  combination are pushed to further cover the shaft  18 , they are inserted through the division wall through-hole  42 . As can be seen in  FIG. 5 , the components are dimensioned where the through-hole  42  diameter is slightly larger than the outer diameter of the impeller annular wall  108 , and the inner diameter of the shaft sleeve second end  138  is slightly larger than the shaft second diameter D2. The shaft sleeve second end  138  includes a chamfer  137  at the tip to facilitate insertion into the third counter bore  98  of the impeller  22 . The shaft sleeve second end  138  generally has an outer diameter just greater than the diameter of the impeller annular wall  108 , and the shaft sleeve second end  138  can have a reduced diameter area  139  that is machined to have a diameter less than that of the second end  138  generally and still just greater than that of the inner diameter of the impeller annular wall  108 . The reduced diameter area  139  is compressed to be received within the annular wall  108 . 
         [0039]    The shaft  18  is received into the bore  140  of the shaft sleeve  20  until the threaded extension  132  contacts the internally threaded insert  102  that has been welded to or overmolded into the impeller  22 . The impeller  22  and shaft sleeve  20  are then rotated clockwise so that the right-hand threads of the threaded extension  132  threadably engage the internal threads of the internally threaded insert  102 . Because the shaft  18  is fixedly attached to the motor  12 , the threadable engagement of the impeller  22  with the threaded extension  132  causes the impeller  22  and the shaft sleeve  20  to be pulled or driven towards the motor  12 . The shaft sleeve  20  applies the force F to the shoulder  160  of the annular ring  148  of the sealing device  24 , forcing the sealing device  24  to engage the sloped wall  128  of the shaft  18 . This force causes the receiving area  150  of the sealing device  24  to be deformed such that the circumferential outer wall  146  is deformed in a direction toward the gap  164  and the shaft receiving area  150  is deformed radially outward as it is forced along the increasing diameter of the sloped wall  128 . This deformation generates a fluid tight seal between the sealing device  24  and the shaft  18 , while the force F applied to the shoulder  160  generates a fluid tight seal between the sealing device  24  and the shaft sleeve  20 . The impeller  22  may be tightened until it is determined than an adequate seal has been generated, or until the threaded extension  132  is fully threaded into the internally threaded insert  102 , at which point the shaft end wall  130  engages the second shoulder  106  restricting further translation. 
         [0040]    With the impeller  22  secured to the shaft  18 , the end cap  16  can be attached to the immersible pump. The o-ring  72  is placed in the chamber  70  formed by the L-shaped extension  62  extending from the end cap  16 . The end cap  16  is inserted into the second portion opening  50  of the impeller housing  14  so that it is housed in the second portion counter bore  52 . The end cap  16  is inserted so that the tubular region  58  protrudes from the impeller housing opening  50 . Further, the end cap  16  is inserted so that the extension  68  engages the radial shoulder  56 , restricting the end cap  16  from being inserted further into the impeller housing  14 . When the end cap  16  is fully inserted, the snap ring  74  is snapped into the circumferential recess  54 , securing the end cap  16  in place. When the end cap  16  is secured in place, the o-ring  72  is compressed between and engages the L-shaped extension  62  and the inner wall of the counter bore  52 , generating a fluid tight seal so that fluid can only enter the impeller housing  14  through the end cap inlet  64 . 
         [0041]    The immersible pump  10  of the present invention may be provided as a fully assembled device or as a kit for assembly. Further, the immersible pump  10  may be capable of disassembly by a user so that parts can be replaced or removed for maintenance or replacement. If provided as a kit, the immersible pump  10  may be constructed as described above. 
         [0042]    In operation, the immersible pump  10  is constructed as previously described and vertically placed in a fluid, such as a corrosive liquid chemical, with the end cap  16  being at the bottom, such that the impeller housing  14  is partially immersed in fluid. A conduit (not shown) can extend into the fluid from the inlet  64 . As shown in  FIG. 3 , the elevation E of the fluid surface is at an intermediate position along the impeller housing  14 . The impeller housing  14  is preferably inserted in the fluid with the second portion  30  submerged and elevation E being below the elevation of the drain hole  40 . As illustrated, the entire impeller  22  can be submerged so as to effectuate desirable pumping operation. 
         [0043]    When the impeller  22  is submerged, the motor  12  is turned on causing the shaft  18  to rotate, which in turn causes the sealing device  24 , shaft sleeve  20  and impeller  22  to rotate. The rotation causes the impeller rear flutes  90  and front flutes  116  to change the pressure and force fluid out the outlet  44  and through the hose  46  or pipe to a target location. This change in pressure also pulls water in from the end cap inlet  64  allowing for a continuous pumping operation. During operation, and especially when the motor  12  is turned-off, fluid may enter the second shaft chamber  36  and may commonly splash upwards. It is desirous to restrict fluid from contacting the motor  12  and shaft  18  or entering the space that may exist between the shaft  18  and the shaft sleeve  20 . If fluid were to enter the shaft sleeve  20 , an imbalance may occur causing the impeller  22  to experience violent vibration and break. Also, fluid such as corrosive liquid chemicals could corrode the metal of the shaft  18 . The drain hole  40  provides an escape for any fluid that may build up in the first portion  28  of the impeller housing  14 , while the sealing device  24  inhibits fluid from entering the space between the shaft  18  and the shaft sleeve  20 . 
         [0044]    It will be understood that the embodiments of the present invention described herein are merely exemplary and that a person skilled in the art may make many variations and modifications without departing from the spirit and the scope of the invention. All such variations and modifications, including those discussed above, are intended to be included within the scope of the invention as defined by the appended claims.