Abstract:
A bearing isolator for controlling fluid flow includes a static component fixed relative to a housing and a rotational component fixed relative to a shaft. The static and rotational components are held axially relative to each other and an annual sealing member is provided. The annual sealing member has a first position in contact with both the static and rotational components and a second position in contact with either, or both, of the static or rotational components. The profile of the static and rotational components is shaped to create a flow path between them with the flow path having at least one feature to slow the flow of fluid therethrough.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to bearing protectors and their use in rotating equipment, especially devices, which prevent the ingress or egress of a fluid or solid to a cavity, preventing undue deterioration of equipment life. Such devices are also often referred to as bearing seals or bearing isolators. The use of such rotary seals extends beyond the protection of a bearing in rotating equipment. Accordingly, while reference will be made below to bearing Isolators, it should be understood that this term is used, as far as the invention is concerned, in connection with much wider uses. More broadly, the term isolator device may be used. 
       BACKGROUND TO THE INVENTION 
       [0002]    An Isolator Device, or Bearing Isolator, is typically used to prevent the ingress of fluid, solids and/or debris into the bearing chamber whilst equally preventing the egress of fluid and/or solids from the bearing chamber. Typically a Bearing Isolator prevents water and dust particles from entering the bearing chamber and grease or oil from leaking out. 
         [0003]    There are two commonly used types of bearing protection which are categorised as: Repeller or Labyrinth Bearing Isolators; and Mechanical Seal Bearing Isolators. The invention described in this document follows the former of these two categories and is labyrinthine in design; consisting of a rotating element and a stationary element both of which have inversely similar profiles which fit together forming a complex or torturous path. 
         [0004]    It has been observed that when bearing chambers are in use, the temperature within the bearing chamber rises above that of the ambient temperature of the surrounding environment. When this occurs a pressure differential is created between the bearing chamber and the atmosphere such that there is a higher pressure in the bearing chamber. To relieve this pressure a static shut-off device can be employed, extensively detailed in Patent number US20100219585A1. 
         [0005]    More simply a single O Ring can be used in contact with both the rotary and stationary elements of the proposed invention such that the O Ring rests on two surfaces thus creating a seal when the bearings are not in use. When the bearings are in use the O Ring dynamically lifts off the contacting surface of the rotary element thus creating a path through which pressure can be released. 
         [0006]    Reference is made to Patent number WO2008155530A1 and U.S. Pat. No. 3,044,787 wherein it is substantially described that a sealing O Ring held on a angled surface such that in dynamic operation where a micro gap is formed between two intended surfaces. 
         [0007]    It is beneficial that all Bearing Isolators are unitised in their design such that when they are built up they form a single element, thus reducing the chance of tampering, damage or loss of parts. In order to achieve this several methods are employed, including but not limited to the use of a circlip or PTFE ring to create an interlocking part. Methods which use a dedicated component such as a circlip or PTFE ring tend to be more expensive and add complexity to the supply chain. It has also been noted that tolerencing in the PTFE shield can have an effect on the performance of the seal and with circlips it is necessary to have them situated such that they are relatively stationary. 
         [0008]    Reference is made to Patent number WO2012075254; wherein is described a labyrinth style bearing protector which incorporates an interlockable stator and rotor. 
       STATEMENTS OF INVENTION 
       [0009]    The present invention is directed to a device comprising a static component fixed relative to a housing and a rotational component fixed relative to a shaft, the static component and rotational components held axially relative to each other, wherein the means of holding the rotor axially relative to the stator is through a contacting surface such that the minimum axial distances between the stator and the rotor are substantially constant and wherein the contacting annular surface is designed to initially wear to the point that a microgap is formed between the stator and rotor. The use of a contacting surface, which is preferably annual, allows for the components to be aligned using the contact of the components to ensure that they are positioned correctly. The contacting surface, which may be in the form or a sacrificial part or nib, ensures correct alignment of the parts because the annular surface can be positioned using sufficient force to ensure that it is in place, without the risk of it being misaligned or forced too far in. When the device is then operated for the first time, the surface, or nib, is worn away and a gap is created to allow the parts to rotate freely. Such an alignment aid is particularly advantageous where the parts may be arranged with parallel surfaces due to the decreased risk of off-parallel positioning. 
         [0010]    The component featuring the sacrificial surface may be formed in a material that is softer than to surface that is to be contacted to ensure that it is worn away upon rotating the respective part. Alternatively, the sacrificial surface may comprise a surface coating applied to the component part so that the components may comprise the same materials with the sacrificial surface being readily removed by wearing upon operation. 
         [0011]    More preferably, the contacting annular surface is designed to initially wear to the point that a microgap is formed between the stator and rotor. Where in the wearing surface aids in the first instance to set the internal clearances and in the second instance to better protect against the ingress of fluids and/or solids. 
         [0012]    The invention may extend to an isolator device for use in controlling fluid flow, wherein the isolator device comprises a static component fixed relative to the housing and a rotational component fixed relative to a shaft, the static component and rotational component held axially relative to each other, wherein an annular sealing member is provided, the annual sealing member having a first position in contact with both the static component and the rotational component and a second position in contact with either or both of the static component and the rotational component, wherein the profile of the static and rotational components are shaped to create a flow path between them and wherein the flow path comprises at least one feature to slow the flow of fluid therethrough. The use of at least one feature to slow the fluid through the flow path allows for a filtering mechanism to be introduced to reduce the risk of potentially harmful solids and/or fluids ingressing through the system. The flow path may comprise bends, corners, curves, baffles, protrusions, tapering, filters and/or other elements, such as a tortuous shape. 
         [0013]    The ability for the annual sealing member to move from a first position to a second position provides a pressure relief system whilst the rotational component is rotating relative to the static component. 
         [0014]    According to the present invention there is provided a Bearing Isolator for use in hindering fluid flow between a static component, herein referred to as a housing, a rotational component, herein referred to as a shaft, wherein is included a sealing stationary component, herein referred to as the stator, which is relatively fixed with the housing such that it can be considered a primary sealing component, a rotary component, herein referred to as the rotor, which is relatively fixed with the shaft such that it can be considered to be a secondary sealing component and a tertiary annular sealing member which can be said to be in contact with both the stator and rotor whilst the shaft is stationary and in a secondary state whilst the shaft is in motion such that it is in a non permanent state of contact with either or both the stator and rotor and wherein is included a means for ensuring that the stator and rotor are held axially relative to each other and further where the profiles of said stator and rotor are such that a tortuous path is formed between their respective profiles in such a manner as to aid the repelling and expulsion of fluids and/or solids and furthermore is additionally included in the profiles of the stator and rotor a diameter that is equal to or less than that of an axially contained diameter situated on the opposing component. 
         [0015]    Advantageously, the profile of a first component comprises an annular recess and the profile of the other component comprises an annular protrusion and wherein the protrusion of the other component is received within the recess of the first component to form part of the flow path. 
         [0016]    Preferably, the protrusion is substantially at one edge of the first component and forms a lip that is received within a corresponding recessed edge of the other component, thereby creating an overhang. 
         [0017]    Preferably, the outermost part of the stator is such that it is the same or lesser in diameter to that of the largest diameter of the rotor. More preferably, the diameter of the outermost part of the stator is lesser then the largest diameter of the rotor. Such design aids to improve the labyrinthine profile of the seal in order to reduce the velocity of potentially harmful fluids and/or solids and preventing their ingress. The profile of the outermost part of the static component provides a means of unitisation, between the stator and rotor. The outermost part of the static component may comprise a lip and the rotational component may comprise a corresponding recess. 
         [0018]    Preferably, the profile of the outmost part of the stator provides a means of unitisation between the stator and rotor. More preferably, the unitisation is such that the rotor passes through a state of interference with the stator during assembly. Such unitisation allows for cost effective assembly and minimises the potential for loss of parts or tampering. 
         [0019]    Preferably, the section of profile of the rotor which forms the largest diameter is such that the diameters of the profile sections immediately adjacent on the stator are lesser in diameter at their lowest point. More preferably, the adjacent surfaces are angled to create a deflecting surface to the normal path of the labyrinth, such that the path of entrance through the labyrinth is significantly deflected further reducing the velocity of harmful fluids and/or solids and providing a self perpetuating barrier. 
         [0020]    Preferably, the means of holding the rotor axially relative to the stator is through a contacting annular surface such that all internal clearances are set as designed on installation. 
         [0021]    Preferably, the tortuous path is formed through one or more concentrically protruding profiles. More preferably, the protruding profiles are concentrically lesser in diameter such that it can be said that they are interlaced. A profile formed in such a manner creates a more arduous path for ingressed fluids and/or bodies to get through. 
         [0022]    Preferably, the tortuous path that is formed by the interfacing sections has included in its profile one or more annular grooves. The annular grooves further aid in the prevention of ingress. 
         [0023]    Preferably, there is included in the lowest gravitational point of the stator an internally protruding void such that the ingress of fluid and/or solids may be removed from the internal cavity of the isolator device. More preferably, the internally protruding void allows for the release of ingressed fluids and/or solids from all internal cavities situated prior to the tertiary annual sealing member. The protruding void, or cut out, therefore allows all ingressed fluids and/or solids to be removed before they are able to enter the sealing cavity. 
         [0024]    Preferably, the tertiary sealing member, or toroidal O Ring, is situated on the rotor such that whilst the shaft is rotating the O Ring is continually energised into a lifted state. More preferably, the O Ring is under a small amount of stretch such that it is positively sat on the sealing surfaces of the rotor and stator. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The accompanying drawings are as follows: 
           [0026]      FIG. 1  is a cross sectional view of a first embodiment of a Bearing Isolator in accordance with the present invention; 
           [0027]      FIG. 2  is an enlarge view of part of the system of  FIG. 1 ; 
           [0028]      FIG. 3  is an embodiment of the unitising feature; 
           [0029]      FIG. 4  is a further embodiment of the unitising feature; 
           [0030]      FIG. 5  is another embodiment of the unitising feature; 
           [0031]      FIG. 6  is a cross sectional view of a second embodiment of a Bearing Isolator in accordance with the present invention; 
           [0032]      FIG. 7  is a more detailed view of the embodiment shown in  FIG. 6 ; 
           [0033]      FIG. 8  is a further embodiment of an overhung static component in accordance with the present invention; 
           [0034]      FIG. 9  is a cross sectional view of another embodiment of a Bearing Isolator in accordance with the present invention; 
           [0035]      FIG. 10  is a more detailed view of the embodiment shown in  FIG. 9 ; 
           [0036]      FIG. 11  is a different embodiment of a tortuous path in accordance with the present invention; 
           [0037]      FIG. 12  is yet another embodiment of a tortuous path in accordance with the present invention; 
           [0038]      FIG. 13  is a cross sectional view of another embodiment of a Bearing Isolator in accordance with the present invention; 
           [0039]      FIG. 14  is a more detailed view of the embodiment of the sealing toroidal member shown in  FIG. 13 ; 
           [0040]      FIG. 15  is an embodiment of the sealing toroidal member in accordance with the present invention; 
           [0041]      FIG. 16  is a further embodiment of the sealing toroidal member in accordance with the present invention; 
           [0042]      FIG. 17  is yet a further embodiment of the sealing toroidal member in accordance with the present invention; 
           [0043]      FIG. 18  is a cross sectional view of the lower section of an embodiment of a Bearing Isolator in accordance with the present invention; 
           [0044]      FIG. 19  is a more detailed view of the lower section of  FIG. 18  detailing the drainage port; and 
           [0045]      FIG. 20  is a view of another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]    The invention will now be described, by way of examples only, with reference to the accompanying drawings. 
         [0047]    Referring to  FIG. 1  of the accompanying drawings, there is shown a cross sectional view of a Bearing Isolator  1  which is fitted into a bore  2  and over a rotating shaft  3  of which the bore  2  and the rotating shaft  3  make up a single piece of rotating equipment. Typically included within the bore  2  but not shown in the accompanying drawings is a bearing. The Bearing Isolator  1  consists of a rotary component  4 , a stationary component  5 , a rotary sealing O Ring  6 , a statically sealing O Ring  7  and a dynamically sealing O Ring  8 . 
         [0048]    Referring to  FIG. 2  of the accompanying drawings, there is shown a close up of the interlocking sections of the rotary component  4  and the stationary component  5  where the largest diameter  9  of the rotary component  4  is greater than the following diameter  10  and the preceding diameter  11  of the stationary component  5  such that a horizontal line may not be drawn between the two components and where the largest diameter  9  is adjacent to two inclined annular surfaces  12  and  13  and thus forms a labyrinthine path between the rotary component  4  and the stationary component  5 . Further there is included in the rotary component  4  an inclined surface  14  such that the inclined surface  14  may aid the assembly of the rotary component  4  and the stationary component  5  by concentrically aligning the rotary component  4  and reducing the initial interference between the largest diameter  9  and the following diameter  10 . 
         [0049]    Referring to  FIG. 3  of the accompanying drawings, there is shown a close up of an embodiment of the interlocking section wherein is included a rotary component  15  and a stationary component  16  such that the largest diameter  17  of the rotary component  15  is greater than the following diameter  18  on the stationary component  15 . There is also provided in this embodiment of the design a leading inclined surface  19  which reduces initial interference with the stationary component  15  and aligns on inclined surface  20 . 
         [0050]    Referring to  FIG. 4  of the accompanying drawings, there is shown a close up of an embodiment of the interlocking section substantially described in  FIG. 3  where there is included a rotary component  21  and a stationary component  22  situated such that the stationary component  22  substantially protrudes over the body of the rotary component  21 . 
         [0051]    Referring to  FIG. 5  of the accompanying drawings, there is shown a close up of an embodiment of the interlocking section similarly described in  FIG. 3  and where there is included a rotary component  23  and a stationary component  24  whereby the rotary component is disposed such that it encompasses the stationary component  24  thus providing further protection against the ingress of foreign bodies. 
         [0052]    Referring to  FIG. 6  of the accompanying drawings, there is shown a cross sectional view of a secondary embodiment of a Bearing Isolator  25  which is shown fitted into a bore  26  and over a rotating shaft  27  includes a rotary component  28 , a primary stationary component  29 , an overhanging component  30 , a rotary sealing O Ring  31 , a stationary sealing O Ring  32  and a dynamically sealing O Ring  33 . 
         [0053]    Referring to  FIG. 7  of the accompanying drawings, there is shown a close up view of  FIG. 6  wherein is included an overhanging stationary component  30  which is disposed within stationary component  29  through the use of a press fit which is maintained by the interfering surfaces  34  and  35  situated accordingly on the primary stationary component  29  and the overhanging stationary component  30  and where the internal placement of the rotary component  28  is maintained through the contacting annular surface  36  on the primary stationary component  29  and a further contacting annular surface  37  on the rotary component  28 . 
         [0054]    Referring to  FIG. 8  of the accompanying drawings, there is shown a cross sectional view of an embodiment of a Bearing Isolator where is included a rotary component  38  and a stationary component  39  and where it is shown that the stationary component  39  significantly overhangs the rotary component  38  in such a way as the rotary component  38  is installed through the opposing side of the stationary component  39  thus providing a significant protection to the ingress of foreign bodies. 
         [0055]    Referring to  FIG. 9  of the accompanying drawings, there is shown a cross sectional view of a cross section of an embodiment of a Bearing Isolator in accordance with the present invention. 
         [0056]    Referring to  FIG. 10  of the accompanying drawings, there is shown a detail view of the interfacing profiles of the rotary component  4  and the stationary component  5  that form a tortuous path. Included in the tortuous path profile of the rotary component  4  are two protruding annular profiles  40  and  41  about which are accordingly situated two annular grooves  42  and  43  for preventing the further ingress of fluids and/or solids and where the protruding profiles  40  and  41  are in two spatial voids  44  and  45  which are intended to retain a greater volume of ingressed fluids and/or solids until they are removed through the drainage port not show in this drawing. Further included in the protruding annular profile  40  is an angled surface  46  which is to aid the flow of ingressed fluid and/or solids through the drainage port not shown in this drawing. 
         [0057]    Referring to  FIG. 11  of the accompanying drawings, there is shown a cross sectional view of an embodiment of the tortuous path profile which is comprised of a rotary component  47  and a stationary component  48  and wherein is included within the rotary component two annular grooves  49  and  50  for the prevention and retention of fluids and/or solids and where the primary annular groove  49  is significantly deeper so as to accommodate a greater ingress of fluids and/or solids. 
         [0058]    Referring to  FIG. 12  of the accompanying drawings, there is shown a cross sectional view of an embodiment of the tortuous path profile which is comprised of a rotary component  51  and a stationary component  52  and wherein is included within the rotary component two annular grooves  53  and  54  situated on the same horizontal plane and protruding axially perpendicular such that their accommodating volume is increase. 
         [0059]    Referring to  FIG. 13  of the accompanying drawings, there is shown a cross sectional view of a cross section of the preferred embodiment of a Bearing Isolator. 
         [0060]    Referring to  FIG. 14  of the accompanying drawings, there is shown a detail view of the dynamically sealing O Ring  8  situated between rotary component  4  and stationary component  5  wherein it is in contact with the rotary sealing surface  55  and the stationary sealing surface  56 . During dynamic operation the O Ring  8  is energised by the rotary sealing surface  55  to the point that it lifts up thus relieving any built up pressure created through operation of the rotary equipment. The diameter of the rotary sealing surface  55  is such that when compared with the respective diameter of the O Ring  8  there is a predefined amount of stretch. 
         [0061]    Referring to  FIG. 15 ,  FIG. 16  and  FIG. 17  of the accompanying drawings, there is shown  3  embodiments of the dynamically sealing O Ring  57  situated accordingly between a rotary component  58  and a stationary component  59 . 
         [0062]    Referring to  FIG. 18  of the accompanying drawings, there is shown a cross sectional view of a cross section of an embodiment of a Bearing Isolator in accordance with the present invention. 
         [0063]    Referring to  FIG. 19  of the accompanying drawings, there is shown a detail view of a drainage port  60  situated at the lowest gravitational point of the Bearing Isolator wherein the drainage port  60  is formed through the removal of material from the stationary component  5  such that fluids and/or solids may be drained from the spatial voids  44  and  45 , see  FIG. 10 . 
         [0064]    Referring to  FIG. 20  of the accompanying drawings, there is shown a cross section view of an embodiment of a bearing isolator in accordance with the present invention. It can be seen in said cross section that there is included a shaft  60  and a bore  61  wherein is included an assembly  62  of an embodiment of the invention which includes a rotary  63  and a stationary  64  and bore sealing o ring  65 , a shaft sealing o ring  66  and a dynamic sealing O ring  67 . 
         [0065]    The device may comprise a snap-fit to hold the static and rotational components in axial alignment. The ‘snap fit’ may comprise an arrangement wherein the static and rotational components are held axially relative to one another by a third component. Alternatively, the components may be held in axial alignment by a first part comprising a protrusion on one part and the second part comprising a groove, or recess, that receives the protrusion of the first part. The protrusion and groove cooperate to hold the two parts in constant axial alignment.