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.
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
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.
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.
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.
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.
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.
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:
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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.
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.
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.
Referring to
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.
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.
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.
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.
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.
As shown in
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.
An example method for assembling the immersible pump 10 of
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.
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
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.
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.
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.
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
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.
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.
Number | Date | Country | |
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Parent | 13159161 | Jun 2011 | US |
Child | 15666912 | US |