Elastomer spring mechanical seal

Abstract

1. A mechanical seal assembly comprising: a gland assembly, a rotary seal ring, a stationary seal ring, a sleeve assembly having a flange portion for mounting the rotary seal ring, a cover sealing element mounted on the flange portion and contacting a portion of the rotary seal ring, and an energizer sealing element axially spaced from the cover sealing element and sealing the stationary seal ring and a portion of the gland assembly, the energizer sealing element applying an axial biasing force to the stationary seal ring.

Description

[Technical field]

[0001] Related Applications This application claims priority to U.S. Provisional Patent Application No. 63 / 311,305, filed February 17, 2022, entitled "ROLLING ELASTOMERIC SPRING MECHANICAL SEAL," the contents of which are incorporated herein by reference. [Background technology]

[0002] Conventional mechanical seals are used in a wide variety of environments and settings to provide fluid-tight seals, such as in mechanical equipment. Typically, such mechanical seals are provided around a rotating or reciprocating shaft or rod that is mounted within and protrudes from a stationary machine housing.

[0003] These mechanical seals are used in a wide variety of mechanical devices to provide gas-tight and fluid-tight seals. Typically, such mechanical seals are mounted around a rotating shaft that is mounted in and protrudes from a stationary device. The mechanical seal is typically bolted to the stationary device at the shaft's exit point, thereby preventing pressurized process fluid from exiting the stationary device. Conventional split mechanical seals include face-type mechanical seals, which include a pair of sealing rings that are concentrically disposed around the shaft and axially spaced from each other. Each sealing ring has a number of sealing faces that are biased into sealing contact with each other. Typically, one sealing ring remains stationary while the other ring is coupled to the shaft and rotates therewith. The mechanical seal prevents pressurized process fluid from leaking to the outside or surrounding environment by biasing the sealing faces of the sealing rings into sealing contact with each other. Typically, the rotary seal ring is mounted in a holder assembly or sleeve that is disposed within a chamber formed by the gland assembly and the fastener. When a holder assembly is used, the holder assembly may comprise a pair of holder halves or sections that are screwed together. Similarly, the gland assembly may comprise a pair of gland halves or sections that are also screwed together. Seal rings are also often split into sections, each section having a pair of sealing surfaces, so that each ring is a split ring that can be fitted onto a shaft without releasing one of the shaft ends.

[0004] A conventional mechanical seal has rotating and stationary components that are threaded onto a shaft and then bolted to the equipment being sealed. The rotating seal face is inserted into a rotating metal clamp after the sections are threaded onto the shaft. The stationary face and gland sections are then assembled and the split gland assembly is then bolted to the pump housing. Alternatively, the stationary and rotating sealing components may be preassembled into a subassembly that is then attached to the shaft.

[0005] Conventional mechanical seals are typically not easily able to adequately seal against slurry-type process fluids, which can degrade sealing performance over time, necessitating repairs or replacements. This increases the overall maintenance costs of the equipment and typically negatively impacts plant performance as the equipment is shut down for routine service. Summary of the Invention

[0006] The present invention relates to a mechanical seal assembly for providing a fluid seal between a rotating shaft and a stationary surface of an equipment housing and / or gland assembly used to seal process fluids or slurries with high abrasive particle content. The mechanical seal assembly includes first and second axially adjacent annular seal ring elements that allow for large axial adjustment of the shaft without disassembly of the seal while protecting the seal components from the abrasive process environment. The first rotating seal ring element rotates with the shaft relative to a second stationary or fixed seal ring element. A stationary housing such as a gland assembly houses a second stationary seal element coupled to an elastomeric seal element such as an axial rolling spring type seal element. The axial rolling spring type seal element has a bend region between the sealing faces of the seal ring elements to provide an axial preload or biasing force and a cover portion that covers a portion of the stationary seal ring. One end of the seal element is coupled to an outwardly extending surface of the gland assembly that would normally be exposed to the slurry. The expanded spring surface protects the exposed stationary annular housing from abrasive particles and provides a secondary axial sealing surface between the device and the stationary housing. Additionally, the present invention may employ a second sealing element disposed within the mechanical seal assembly to couple to a sleeve assembly that mounts the rotary seal ring and cover a portion of the outer surface of the rotary seal ring. The sealing element may include connection features that facilitate coupling of the sealing element to the sleeve and the rotary seal ring.

[0007] The present invention relates to a mechanical seal assembly for mounting around a shaft to seal a slurry within a stationary device. The mechanical seal assembly includes a gland assembly configured to couple to the stationary device. The gland assembly has a radially extending outer surface and an opposing radially extending inner surface, the body extending from an axially outer end to a radially inner end, a portion of the radially inner end forming an overhang. The inner surface has a gland channel formed in the overhang. The gland assembly further includes a rotary seal ring having an outer surface and configured for rotational movement when coupled to the shaft, a stationary seal ring disposed in sealing contact with the rotary seal ring to form a fluid seal between the rotary seal ring, and a sleeve assembly having a body with a flange portion formed at a first end defining a space for mounting the rotary seal ring, and a sleeve portion having an outer surface. The body of the sleeve assembly includes an inner surface having an engagement channel formed at the first end. A support ring element is further provided and positioned to contact the outer surface of the sleeve portion of the sleeve assembly.

[0008] The mechanical seal assembly also includes a cover sealing element and an energizer sealing element. The cover sealing element is disposed to contact at least a portion of the flange portion of the sleeve assembly and at least a portion of the outer surface of the rotary seal ring. The outer surface of the cover sealing element has a flat end surface portion with a radially inwardly extending end lip formed at a terminal region and a tapered end surface portion joined to the flat end surface portion. The inner surface of the cover sealing element includes a first inner surface having a larger diameter than a second radially inward stepped inner surface, the first inner surface and the second inner surface being joined by a radially extending stepped wall surface having a wall channel formed therein. The wall channel includes a wall lip portion overlying a portion of the wall channel, a bottom of the flange portion mounted within the wall channel, and the wall lip portion mounted within and engaged with the engagement channel.

[0009] A cover channel is formed in the first inner surface of the cover sealing element, and the flange portion of the sleeve assembly has a protrusion extending outwardly from an outer circumferential surface of the flange portion and for mounting within the cover channel.

[0010] The energizer sealing element of the mechanical seal assembly is axially spaced from the cover sealing element and positioned to contact at least a portion of the stationary seal ring to apply an axial biasing force to the stationary seal ring. The energizer sealing element has a body including a cover portion formed at a first end and a bend portion formed at an opposing second end, the bend portion having an end region including a connection feature mounted within the gland channel for coupling the bend portion to the gland assembly. The inner surface of the cover portion of the energizer sealing element has one or more protrusions formed thereon, and the stationary seal ring has an outer surface with a stator channel formed thereon, the protrusions configured to be mounted within the stator channel of the stationary seal ring when assembled. The second inner surface of the cover sealing element has one or more protrusions formed thereon that engage the shaft to form a fluid seal between the cover sealing element and the shaft.

[0011] According to the present invention, the inner surface of the cover portion of the energizer sealing element includes a stepped wall portion including a first stepped wall surface transitioning to a second stepped wall surface, and the support ring element has a first end positioned adjacent to the stationary seal ring and an annular wall feature formed at the first end, and in an assembled state, the inner surface of the cover portion contacts the outer surface of the stationary seal ring and the second stepped wall surface of the cover portion contacts the annular wall feature of the support ring element.

[0012] When the energizer sealing element is coupled to the gland assembly and the stationary seal ring, the bent portion of the energizer sealing element is disposed in a biased position, and when disposed in the biased position, the bent portion of the energizer sealing element forms a bent intermediate portion to bias the stationary seal ring.

[0013] The present invention also relates to a mechanical seal assembly including a gland assembly configured to be coupled to the stationary device, a rotary seal ring having an outer surface and configured for rotational movement when coupled to the shaft, a stationary seal ring disposed in operative sealing contact with the rotary seal ring to form a fluid seal between the rotary seal ring, and a sleeve assembly having a body with a flange portion formed at a first end defining a space for mounting the rotary seal ring, and a sleeve portion having an outer surface. The body of the sleeve assembly has an inner surface having an engagement channel formed at the first end. The mechanical seal assembly further includes a cover sealing element disposed to contact at least a portion of the flange portion of the sleeve assembly and at least a portion of the outer surface of the rotary seal ring, and an energizer sealing element axially spaced from the cover sealing element and disposed to contact at least a portion of the stationary seal ring to apply an axial biasing force to the stationary seal ring. The energizer sealing element includes a body having an outer surface and an inner surface, the energizer sealing element body including a cover portion formed at a first end and a flex portion formed at an opposing second end, the flex portion having an end region including a connection feature mounted within the gland channel for coupling the flex portion to the gland assembly.

[0014] The mechanical seal assembly further includes a support ring element positioned in contact with the outer surface of the sleeve portion of the sleeve assembly, the support ring element having an outer surface and an inner surface.

[0015] The gland assembly has a radially extending outer surface and an opposing radially extending inner surface, the body extends from an axially outer end to a radially inner end, a portion of the radially inner end defining an overhang, and the inner surface has a gland channel formed in the overhang.

[0016] The outer surface of the cover sealing element has a flat end surface portion with a radially inwardly extending end lip formed at a terminal region and a tapered end surface portion joined to the flat end surface portion. The inner surface of the cover sealing element comprises a first inner surface having a larger diameter than a second radially inward stepped inner surface, the first inner surface and the second inner surface being joined by a radially extending stepped wall surface having a wall channel formed therein. The wall channel comprises a wall lip portion overlying a portion of the wall channel, a bottom of the flange portion being mounted within the wall channel, the wall lip portion being mounted within and engaging the engagement channel. The first inner surface of the cover sealing element has a cover channel formed therein, and the flange portion of the sleeve assembly has a protrusion extending outwardly from an outer circumferential surface of the flange portion for mounting within the cover channel.

[0017] According to the invention, the inner surface of the cover portion of the energizer sealing element has one or more protrusions formed thereon, and the stationary seal ring has an outer surface with a stator channel formed therein, the protrusions being configured to be mounted within the stator channel of the stationary seal ring when assembled. Furthermore, the inner surface of the cover portion of the energizer sealing element includes a stepped wall portion including a first stepped wall surface transitioning to a second stepped wall surface. The support ring element has a first end disposed adjacent to the stationary seal ring and an annular wall feature formed at the first end. In an assembled state, the inner surface of the cover portion contacts the outer surface of the stationary seal ring, and the second stepped wall surface of the cover portion contacts the annular wall feature of the support ring element. [Brief description of the drawings]

[0018] These and other features and advantages of the present invention will become more fully understood with reference to the following detailed description and the accompanying drawings, in which like reference characters indicate like parts throughout the several different views, which illustrate the principles of the invention and which, although not to scale, show relative dimensions.

[0019] [Figure 1] FIG. 1 is a partial cross-sectional perspective view of a mechanical seal assembly in accordance with the teachings of the present invention. [Diagram 2] Figures 2A and 2B are perspective views of a first and second embodiment of a rotating sealing element configured to couple to a sleeve assembly of a mechanical seal assembly of the present invention. [Diagram 3] FIG. 3 is a cross-sectional perspective view of a rotating cover sealing element of the present invention. [Figure 4] FIG. 4 is a cross-sectional view of a rotating cover sealing element of the present invention. [Diagram 5] FIG. 5 is a partial cross-sectional view of the rotating cover sealing element of the present invention. [Figure 6] FIG. 6 is a partial cross-sectional perspective view of a mechanical seal assembly illustrating the coupling of a cover sealing element to a sleeve assembly in accordance with the teachings of the present invention. [Figure 7] FIG. 7 is a cross-sectional perspective view of an energizer sealing element used in the mechanical seal assembly of the present invention. [Figure 8] FIG. 8 is a cross-sectional perspective view of an energizer sealing element used in the mechanical seal assembly of the present invention. [Figure 9] FIG. 9 is a partial cross-sectional perspective view showing an energizer sealing element installed in the mechanical seal assembly of the present invention. [Figure 10]FIG. 10 is a partial cross-sectional perspective view of an energizer sealing element installed in the mechanical seal assembly of the present invention, showing the sealing element coupled to a gland assembly, a support ring element, and a stationary seal ring. [Figure 11] FIG. 11 is a partial cross-sectional perspective view showing an energizer sealing element installed in the mechanical seal assembly of the present invention. BEST MODE FOR CARRYING OUT THEINVENTION

[0020] The present invention provides a mechanical seal assembly employing a cover sealing element and an energizer sealing element for sealing selected components of the seal assembly, including a seal ring, a sleeve assembly, and at least a portion of a gland assembly. The present invention is described in the following description with reference to the illustrated embodiments. Those skilled in the art will appreciate that the present invention may be implemented in many different applications and embodiments, and is not specifically limited to the specific embodiments described herein.

[0021] As used herein, the terms "mechanical seal assembly" and "mechanical seal" are intended to include various types of mechanical fluid sealing systems, including single or integral seals, split seals, concentric seals, spiral seals, tandem seals, dual seals, cartridge seals, gas seals, and other known mechanical seal and sealing types and configurations.

[0022] The term "shaft" is intended to refer to any suitable device to which a mechanical seal can be attached in a mechanical system, including axles, rods, and other known devices. A shaft may move in any selected direction, such as, for example, rotationally or reciprocally.

[0023] As used herein, the terms "axial" and "axially" refer to directions generally parallel to the axis of any shaft. As used herein, the terms "radial" and "radially" refer to directions generally perpendicular to the axis of any shaft. The terms "fluid" and "fluids" refer to liquids, gases, and combinations thereof.

[0024] As used herein, the term "axially inner" or "axially internal" refers to the portion of the mechanical seal proximal to the stationary equipment and stationary equipment on which the mechanical seal is used. Conversely, as used herein, the term "axially outer" or "axially external" refers to the portion of the stationary equipment and seal assembly distal to the mechanical system.

[0025] As used herein, the term "radially inner" refers to the portion of the seal assembly proximal to any shaft. Conversely, the term "radially outer" refers to the portion of the mechanical seal distal from any shaft.

[0026] As used herein, the terms "fixture" and / or "stationary surface" are intended to include any suitable stationary structure that accommodates a shaft or rod to which a seal with a gland is secured.

[0027] As used herein, the terms "process medium" and / or "process fluid" generally refer to the medium or fluid being transported through a stationary apparatus. In a pump application, for example, the process medium is the fluid being pumped through the pump housing.

[0028] The term "gland" as used herein is intended to include any suitable structure that enables, facilitates, or assists in the fastening of a mechanical seal to a stationary device, while at the same time at least partially surrounding or containing one or more seal components. If desired, the gland may also provide fluid access to the mechanical seal. Those of ordinary skill in the art will also appreciate that the gland assembly may form part of the mechanical seal assembly or part of the stationary device.

[0029] The term "slurry" or "slurry process fluid" as used herein is intended to include process fluids or other types of fluids that contain solid particles or particulates. Thus, a slurry can be a mixture of denser solid matter particulate material suspended in a carrier medium such as water. The most common use of slurries is as a means of transporting solids or separating minerals, where the carrier medium is pumped by a device such as a centrifugal pump employing the mechanical seal assembly of the present invention. The solid particles can be of various sizes. The particles settle below a certain transport rate, and the mixture can behave like a Newtonian or non-Newtonian fluid. Depending on the mixture, the slurry can be abrasive and / or corrosive. The fluid can be Newtonian, having or exhibiting Newtonian properties, such as a change in viscosity only in response to changes in temperature or pressure. Specifically, the viscosity of a Newtonian fluid is constant for a constant temperature, regardless of the amount of shear applied to the fluid. Thus, a Newtonian fluid has a proportional relationship between viscosity and shear stress. Newtonian fluids have the ability to precipitate particulates relatively easily and quickly from the carrier medium. Newtonian fluids are also called settling slurries. The particulates in a settling slurry are typically about 100 μm or larger. The fluid may also be a non-Newtonian fluid that has or exhibits non-Newtonian properties, where the viscosity of the non-Newtonian fluid decreases or increases as a function of the type of fluid when a shear force is applied to it. Non-Newtonian fluids are also called non-settling slurries (e.g., homogeneous mixtures) because particulates are less likely to settle in non-Newtonian fluids. In non-settling slurries, the fluid contains a more homogeneous mixture of fluid and particulates. The particulates in a non-settling slurry are typically less than about 100 μm. There are various types of slurries, such as clean slurries, light slurries, and heavy slurries.

[0030] A mechanical seal assembly of the present invention is shown, for example, in FIG. 1. The illustrated mechanical seal assembly 10 is concentrically mounted around a shaft 12 extending along a first or shaft axis and is fixed to a stationary device 14, such as a pump or other mechanical device. The shaft 12 may be at least partially disposed within or adjacent to the stationary device 14. The mechanical seal assembly 10 may be configured to form a fluid-tight seal, thus preventing process fluids or media, which may include slurries, from exiting the stationary device and preventing damage or deterioration of the mechanical seal. The fluid-tight seal is achieved with sealing members, shown as a pair of sealing rings 20 and 30. The illustrated sealing rings include a first or rotating seal ring 20 and a second or stationary seal ring 30 disposed in operative sealing contact with one another to form a seal therebetween. The stationary seal ring has a body with an outer surface having a rotor channel or groove 22 formed therein. The rotor channel 22 may be sized and configured to receive a sealing element 150, such as an O-ring. Similarly, the stationary seal ring 30 has a body with an outer surface having a stator channel or groove 32 formed therein. The stator channel 32 is also sized and configured to receive a sealing element. The stationary seal ring 20 and the rotary seal ring 30 each have a smooth arcuate sealing surface and are biased into sealing contact with each other by any suitable biasing assembly, such as an energizer sealing element 130. The seal rings 20 and 30 may be integral or each may be split into a pair of seal ring segments to facilitate installation of the mechanical seal assembly 10. The sealing surfaces of the seal rings 20 and 30 provide a fluid-tight seal operable under a wide range of operating conditions. According to one embodiment, the seal rings 20 and 30 may be similar or identical in shape.

[0031] The mechanical seal assembly 10 may further include a gland assembly 50 and a holder or sleeve assembly 60 mounted within the gland assembly 50 and within the retainer 14. The illustrated sleeve assembly 60 may have any selected shape or configuration, and in the illustrated embodiment has a body formed as a sleeve disposed about and rotatably coupled to the shaft 12. The sleeve assembly 60 is disposed within the interior space 18 formed by the gland assembly 50 and the retainer 14. The body of the sleeve assembly 60 has an extended sleeve portion 62 and a flange portion 64 at an axially inner end configured to form a channel 66 that defines a space for receiving and retaining the rotary seal ring 20. According to one embodiment, the flange portion 64 has a generally or substantially U-shaped configuration. The sleeve portion 62 has an outer surface 68A and an opposing inner surface 65B with any selected number of grooves formed therein for mounting one or more sealing elements, for example, for mounting the sealing element 154. The sealing element 154 is configured to provide a seal between the sleeve 60 and the shaft 12 to seal the process fluid within the fixture 14. Additionally, the inner surface 68B is formed with cutouts to provide an engagement channel or area 70 located at the end of the sleeve in the region of the flange portion 64, which provides a seal retention feature. The engagement channel 70 is configured to receive a portion of a protective seal, such as a portion of the cover sealing element 90.

[0032] 1 and 10, the illustrated mechanical seal assembly 10 also includes a support ring element 80 mounted on the outer surface 68A of the sleeve portion 62 of the sleeve 60. The support ring element 80 includes a body having an outer surface 82 and an opposing inner surface. The outer surface 82 includes a wall portion 84 formed at an axially inner end having a stepped wall surface 86 extending radially outward from the outer surface 82. The wall portion 84 includes a connecting feature 88 extending axially outward therefrom that is configured to be received within a complementary shaped channel or seat 36 formed in the stationary seal ring 30 for mechanically coupling the support ring element 80 thereto. The complementary shaped channel 36 is formed at an end of the stationary seal ring 30 opposite the sealing surface. The support ring element 80 is thus mechanically coupled to the stationary seal ring 30 such that it remains stationary during operation of the seal. The support ring element 80 is also positioned to contact the sealing elements, such as the energizer sealing element 130, to help support the sealing elements during operation and under various pressure conditions.

[0033] The mechanical seal assembly 10 also includes a locking ring assembly 100 that fits around the end of the sleeve portion 62 of the sleeve assembly 60 for securing the sleeve assembly 60 to the shaft 12. Specifically, the locking ring assembly 100 employs a pin 102 for securing the sleeve assembly 60 to the shaft 12 so that the sleeve assembly can rotate therewith.

[0034] The gland assembly 50 is concentrically disposed about the shaft 12 and attached to the stator 14 via known fastening mechanisms and according to known fastening techniques. The gland assembly 50 includes a body having an outer surface 52 and an opposing inner surface 54. The body is concentric and may be configured and sized to extend from a radially outer end to a radially inner end that extends radially inwardly relative to the stator 14 into the space 18 to form an overhang 58. The inner surface 54 includes a groove 56 formed in a cut-out area in the region of the overhang 58, the groove 56 being sized and configured to receive a portion of a sealing element, such as the energizer sealing element 130. Additionally, the mechanical seal assembly 10 may include an annular gland sealing element or gasket 158 ​​that may be disposed between the gland assembly 50 and the stator 14 to form a fluid seal therebetween.

[0035] The mechanical seal assembly 10 also includes a pair of specially configured sealing elements that help protect the components of the mechanical seal assembly when the mechanical seal is being used to seal a slurry material, which forms the process fluid contained within the stationary apparatus 14. According to one embodiment, the mechanical seal assembly 10 may employ a cover sealing element 90 disposed axially inwardly within the seal and positioned to cover at least a portion of the flange portion 64 of the sleeve assembly 60 and at least a portion of the rotating seal ring 20. The cover sealing element 90 is configured to couple to the sleeve assembly and rotate unitarily therewith. The mechanical seal assembly 10 also includes an energizer sealing element 130 disposed at an axially outer end of the mechanical seal assembly and positioned to apply an axial biasing force to the stationary seal ring 30 to urge the sealing faces or surfaces of the seal rings into mating sealing engagement with one another and form an outer seal to prevent the process fluid from leaking from the stationary apparatus 14 to the surrounding environment. A cover sealing element 90 is shown, for example, in FIGS. 1-6. The illustrated cover sealing element 90 includes a body 92 with an outer surface 94 and an inner surface 108. The outer surface 94 has a relatively flat end surface portion 96 that transitions to a tapered end surface portion 98. The tapered end surface portion 98 may be tapered in any selected manner. For example, the tapered end surface portion 98 preferably has a larger diameter at a location 100 adjacent the flat end surface portion 96 and transitions to a smaller diameter at a terminal region 102 of the body 92. According to one embodiment, as illustrated, the tapered end surface portion 98 tapers in a continuous linear manner from the location 100 to the terminal portion or region 102. The flat end surface portion 96 may optionally include a tapered end portion 104 that terminates at a terminal region 106. The flat end surface portion 92 has a lip 110 formed at the outer terminal end 106 that extends radially inwardly and functions as a first capture or retention feature.

[0036] The inner surface 108 of the body 92 of the cover sealing element 90 may include an upper inner surface 108A facing the flat end surface portion 92 and a lower inner surface 108B facing the tapered end surface portion 98. The diameter of the upper inner surface 108A is greater than the diameter of the lower inner surface 108B. Additionally, the inner surface 108A is formed with an annular channel or groove 112. The lower inner surface 108B is stepped radially inwardly relative to the upper inner surface 108A when installed within the mechanical seal assembly to form a stepped wall portion 114. In particular, the upper inner surface 108A is coupled to the lower inner surface 108B by the radially extending stepped wall portion 114. The stepped wall portion 114 may include a wall channel 116 formed for mounting the flange portion 64 of the sleeve assembly 60. The stepped wall portion 114 also includes a wall lip portion 118 that overlies a portion of the wall channel 116. The wall lip and wall channel 116 cooperate with the engagement channel 70 formed in the sleeve assembly 60 to form a second capture or retention mechanism.

[0037] 6, a wall channel 116 formed in the cover sealing element 90 is sized and configured to receive the bottom 72 of the flange portion 64. A lip 118 of the wall channel 116 engages with an engagement channel 70 formed in a cut-out portion of the inner surface 68B of the sleeve assembly 60. The engagement of the lip 118 with the channel 70 aids in the mechanical interlocking or coupling of the cover sealing element 90 and the sleeve assembly 60. Additionally, the end lip 110 overlies the top 78 of the flange portion 64 of the sleeve assembly 60 when assembled. When coupled together, the lip 118 connects with and helps capture the flange portion 64. In this configuration, the projections 76 formed on the outer surface 74 of the flange portion 64 are mounted within channels 112 formed along the upper inner surface 108 of the cover sealing element 90. The projections 76 serve to act as an additional capture or retention mechanism between the cover sealing element 90 and the sleeve assembly 60.

[0038] The lower inner surface 108B of the cover sealing element 90 may optionally include one or more protrusions 120 extending radially inward from the lower inner surface 108B toward the shaft 12. The protrusions 120 are sized and configured to contact the shaft 12 to form a seal between the cover sealing element 90 and the shaft. The protrusions 120 help prevent process media or fluids, such as slurry, from passing along the outer surface of the shaft 12.

[0039] The illustrated cover sealing element 90 helps protect the flange portion 64 of the sleeve assembly 60 and at least a portion of the rotary seal ring 20 from damage (e.g., abrasion) caused by harmful particulates typically present in slurry-type process fluids. Additionally, the cover sealing element 90 helps provide or form a secondary seal between the sleeve assembly 60 and the shaft 12. The illustrated cover sealing element 90 has a number of different capture or retention features formed therein to aid in securing the sealing element to the sleeve assembly. For example, the cover sealing element 90 has a wall groove 116 formed in the stepped wall portion 114 of the inner surface 108 and a corresponding lip 118 to aid in capturing and securing the flange portion 64 of the sleeve assembly 60. Additionally, the outer end 106 of the body 92 is formed with a lip 110 that mates with and secures the top surface 78 of the flange element 64. Additionally, the upper inner surface 108A of the sealing element is formed with a channel 112 for mounting the protrusion 76. The projections and channels 112 further aid in securing the cover sealing element 90 to the sleeve assembly 60 .

[0040] As shown in Figures 2A and 2B, pumping elements 124 may be optionally formed on the outer surface 94 of the cover sealing element 90. The pumping elements 124 may be any selected type of surface feature that aids in moving or pumping the slurry process fluid around the outer surface 94 of the cover sealing element 90. The pumping elements 124 may have any selected shape or configuration and may be formed at any selected location along the outer surface 94. One of ordinary skill in the art will readily appreciate that any number and arrangement of pumping elements 124 may be used based on the teachings herein. As shown in Figure 2A, the pumping elements 124 may be formed only along the tapered end surface portion 98 of the cover sealing element 90. As shown in Figure 2B, the pumping elements 124 may be formed only along the flat end surface portion 96 or along both the flat end surface portion 96 and the tapered end surface portion 98. The pumping element 124 helps to move or evacuate abrasive particles present in the slurry from the seal contact areas (e.g., the sealing surfaces of the seal rings), thereby helping to protect the seal rings and extend the life of the mechanical seal assembly.

[0041] The mechanical seal assembly of the present invention may also include an energizer sealing element 130. As shown, for example, in Figures 1 and 7-11, the illustrated energizer sealing element 130 is mounted or attached around at least a portion of the stationary seal ring 30 and the support ring element 80, and around a portion of the gland assembly 50. The energizer sealing element 130 helps to provide a fluid seal at the outer end of the mechanical seal assembly 10 while simultaneously protecting selected seal components from the slurry process fluid. The illustrated energizer sealing element 130 includes a body 132 having an outer surface 134 and an inner surface 136. The body 132 also includes a cover portion 138 formed at an axially inner or interior end and a bend portion 140 formed at an opposing axially outer or exterior end. The cover portion 138 includes a relatively flat outer surface 134A and an opposing inner surface 136A. The inner surface 136A may have surface features formed thereon, such as protrusions 142. The protrusion may help form a capture or retention mechanism. The outer surface 134A may also include an optional inclined flat surface 134C that transitions to the outer surface 134B that corresponds to the flexure 140. The outer surface 134B includes an end region 146 that includes a connection feature, such as a stepped lip 148. The end region 146 is configured to abut the gland assembly 50. The flexure 140 further includes an opposing inner surface 136B. The inner surfaces 136A and 136B are coupled to one another by a stepped wall surface 144. The stepped wall surface 144 includes a first stepped wall surface 144A that transitions to a second stepped wall surface 144B. The flexure 140 has a thickness less than the cover portion 138 that allows the flexure 140 to bend and flex when installed within the mechanical seal assembly 10. The flexure 140 is disposed in a generally unflexed state or position, for example as shown in FIGS. 7 and 8. In the unflexed position, the flexure 140 has a generally L-shape. When the energizer sealing element 130 is installed within the mechanical seal assembly 10, the flexure 140 may be disposed in a generally flexed or loaded state or position, for example, as shown in FIGS.When in an energized or bent state or position, the bend applies an axial biasing force through the cover portion to the back surface of the stationary seal ring 30 to force the sealing faces or surfaces of the seal ring into sealing contact with each other. When in the bent state, the bend 140 has a generally bent U-shaped configuration as the middle portion 170 of the bend 140 is bent back to form a pressure cavity 172. The bent portion formed by the middle portion 170 forms a spring-like portion that applies an axial biasing force when placed in the bent state. Specifically, the bend of the energizer sealing element forms a bent middle portion for biasing the stationary seal ring when placed in the energized position. The pressure cavity 172 formed by the middle portion allows the slurry to apply a sealing pressure to the bend 140 and to apply a biasing force to the cover portion 138 that is transferred to the stationary seal ring 30. The bend of the energizer sealing element is resilient and flexible and can be bent to form a spring-like middle portion.

[0042] As shown in Figures 1, 10 and 11, when the energizer sealing element 130 is installed in the mechanical seal assembly 10, the cover portion 138 is installed to cover a portion of the outer surface 34 of the stationary sealing element 30. A protrusion 142 formed along the inner surface 136A is aligned with and installed within the channel 32 formed in the outer surface 34 of the stationary seal ring 30. When the cover portion 138 is in this position, the stepped wall surface 144B abuts the wall 84 of the support ring element 80. The outer surface 82 of the support ring element 80 contacts the inner surface 136B of the sealing element to support and position the energizer sealing element 130 relative to the stationary seal ring 30. A connection feature formed in the end region 146 is connectable to the gland assembly 50. Specifically, the connection feature includes a lip 148 that is installed within the gland channel 56. The lip portion 148 is attached and secured between the inner surface 54 of the gland assembly 50 and the stationary device 14 to securely secure the end region 146 therebetween. Additionally, the mechanical alignment and engagement of the projection 142 with the channel 32 of the stationary seal ring and the engagement between the stepped wall surface 144B and the wall 84 of the support ring element 80 provide a number of different capture and retention mechanisms for retaining the energizer sealing element 130 on the stationary seal ring 30. Additionally, the secure attachment of the bent portion 140 of the energizer sealing element 130 to the gland element and the secure attachment of the cover portion 138 to the stationary seal ring 30 and the support ring element 80 allows the bent portion 140 to bend into a bent state to apply an axial biasing force to the stationary seal ring. The bent intermediate portion 170 of the flexure 140 allows the energizer sealing element 130 to operate in a wide range of pressure conditions since the flexure can flex to accommodate pressure fluctuations while still applying a sufficient biasing force to the stationary seal ring 30. The inner diameter of the cover portion 138 can also be sized to form a friction or interference fit with the stationary seal ring 30 when it is fitted over the stationary seal ring.

[0043] The connection feature of the bend 140 of the energizer sealing element 130 may optionally include an additional ridge element 176 housed within a complementary shaped channel formed in the inner surface of the gland assembly 50 .

[0044] Thus, the energizer sealing element 130 helps to locate and position the stationary seal ring 30 at a defined axial location within the mechanical seal assembly 10. Additionally, the energizer sealing element 130, such as the cover portion 138, becomes or forms a secondary seal to protect at least a portion of the outer surface 34 of the stationary seal ring 30 from potential damage from abrasive particulates present within the slurry process fluid. The bent region 140 operates and functions like an energizer diaphragm or spring-biased element and can have a bent outwardly extending shape when installed within the mechanical seal assembly 10. This bent shape serves to absorb pressure fluctuations and form a spring-like portion, thereby applying an axial biasing force to the stationary seal ring 30 to bias the seal. When installed between the gland assembly 50 and the stationary device 14, the bent portion 140 provides or forms an anti-slip feature that maintains the seal balance line within the mechanical seal assembly 10 and applies a biasing preload force to the seal ring. A secondary seal is formed by positioning the portion of the bend 140 between the gland assembly 50 and the stationary device 14, and the partial lining of the stationary gland axial surface serves to protect the surface from abrasive particles in the process fluid.

[0045] The cover sealing element 90 and the energizer sealing element 130 may be constructed of the same or different materials. For example, the sealing elements may be formed from polyurethanes such as thermoset or thermoplastic polyurethane, ethylene propylene diene monomer (EPDM), silicone rubber, reinforced cloth materials, or any type of elastomeric material. The materials used to form the sealing elements are preferably highly wear resistant as compared to the standard metallic materials used in conventional mechanical seal assemblies. These materials may thus be used to protect the components of the seal.

[0046] According to another embodiment, an additional spring element may be provided attached between the energizer seal element 130, the support ring element 80 and the gland assembly 50 to provide an additional amount of spring biasing force to the fixed cell ring.

[0047] It should thus be seen that the present invention effectively attains the objects set forth above, among those made apparent from the preceding description. Since certain changes may be made to the above construction without departing from the scope of the present invention, it is intended that all matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense.

[0048] Moreover, the following claims are to be understood as covering all the general and specific features of the invention described herein, and all statements regarding the scope of the invention are to be deemed to fall within their scope.

Claims

1. 1. A mechanical seal assembly for mounting about a shaft to seal a slurry within a stationary apparatus, comprising: a gland assembly configured to couple to the fastener and having a radially extending outer surface and an opposing radially extending inner surface, the body extending from an axially outer end to a radially inner end, a portion of the radially inner end forming an overhang, the inner surface having a gland channel formed in the overhang; a rotary seal ring having an outer surface and configured for rotational movement when coupled to the shaft; a stationary seal ring disposed in sealing contact with the rotary seal ring to form a fluid seal therebetween; a sleeve assembly having a body with a flange portion formed at a first end defining a space for mounting the rotary seal ring and a sleeve portion having an outer surface, the body of the sleeve assembly having an inner surface with an engagement channel formed at the first end; a support ring element positioned to contact the outer surface of the sleeve portion of the sleeve assembly, the support ring element having an outer surface and an inner surface; a cover sealing element disposed in contact with at least a portion of the flange portion of the sleeve assembly and at least a portion of the outer surface of the rotary seal ring, the cover sealing element having an inner surface and an opposing outer surface, the outer surface having a flat end surface portion with a radially inwardly extending end lip formed at a terminal region and a tapered end surface portion joined to the flat end surface portion; the inner surface of the cover sealing element comprises a first inner surface having a larger diameter than a second radially inward stepped inner surface, the first inner surface and the second inner surface being joined by a radially extending stepped wall surface having a wall channel formed therein; the wall channel including a wall lip overlying a portion of the wall channel; a cover sealing element, the bottom of the flange portion being mounted within the wall channel and the wall lip portion being mounted within and engaging the engagement channel; an energizer sealing element axially spaced from the cover sealing element and positioned to contact at least a portion of the stationary seal ring to apply an axial biasing force to the stationary seal ring, the energizer sealing element having a body with an outer surface and an inner surface; the body of the energizer sealing element includes a cover portion formed at a first end and a bend portion formed at an opposing second end; The flexure has an end region including a connection feature mounted within the gland channel for coupling the flexure to the gland assembly.

2. 2. The mechanical seal assembly of claim 1, wherein the first inner surface of the cover sealing element has a cover channel formed therein, and the flange portion of the sleeve assembly has a protrusion extending outwardly from an outer circumferential surface of the flange portion and for mounting within the cover channel.

3. 3. The mechanical seal assembly of claim 2, wherein the inner surface of the cover portion of the energizer sealing element has one or more protrusions formed thereon, and the stationary seal ring has an outer surface having a stator channel formed therein, the protrusions being configured to be mounted within the stator channel of the stationary seal ring when assembled.

4. The mechanical seal assembly of claim 3 , wherein the connection feature of the bend of the energizer sealing element includes a stepped lip.

5. 4. The split mechanical seal of claim 3, wherein the rotary seal ring has a body with an outer surface having a rotor channel formed therein, and further includes a sealing element sized and configured to be mounted within the rotor channel of the rotary seal ring.

6. 4. The mechanical seal assembly of claim 3, wherein the second inner surface of the cover sealing element is formed with one or more protrusions that engage the shaft to form a fluid seal between the cover sealing element and the shaft.

7. the inner surface of the cover portion of the energizer sealing element includes a stepped wall portion including a first stepped wall surface transitioning to a second stepped wall surface; the support ring element has a first end disposed adjacent the stationary seal ring and an annular wall feature formed at the first end; 4. The mechanical seal assembly of claim 3, wherein in an assembled condition, the inner surface of the cover portion contacts the outer surface of the stationary seal ring and the second stepped wall surface of the cover portion contacts the annular wall feature of the support ring element.

8. 8. The mechanical seal assembly of claim 7, wherein in an assembled state, the connection feature of the bent portion of the energizer sealing element is configured to be disposed between the gland assembly and the fastener.

9. 8. The mechanical seal assembly of claim 7, wherein the bent portion of the energizer sealing element is disposed in a biased position when the energizer sealing element is coupled to the gland assembly and the stationary device, and the bent portion of the energizer sealing element forms a bent intermediate portion to bias the stationary seal ring when disposed in the biased position.

10. 1. A mechanical seal assembly for mounting about a shaft to seal a slurry within a stationary apparatus, comprising: configured to couple to the fixation device; a rotary seal ring having an outer surface and configured for rotational movement when coupled to the shaft; a stationary seal ring disposed in operative sealing contact with the rotary seal ring to form a fluid seal therebetween; a sleeve assembly having a body with a flange portion formed at a first end defining a space for mounting the rotary seal ring and a sleeve portion having an outer surface, the body of the sleeve assembly having an inner surface with an engagement channel formed at the first end; a cover sealing element disposed in contact with at least a portion of the flange portion of the sleeve assembly and at least a portion of the outer surface of the rotary seal ring, the cover sealing element having an inner surface and an opposing outer surface; and an energizer sealing element spaced axially from the cover sealing element and positioned to contact at least a portion of the stationary seal ring to apply an axial biasing force to the stationary seal ring, the energizer sealing element having a body with an outer surface and an inner surface, the body of the energizer sealing element including a cover portion formed at a first end and a flex portion formed at an opposing second end, the flex portion having an end region including a connection feature mounted within the gland channel for coupling the flex portion to the gland assembly.

11. 11. The mechanical seal assembly of claim 10, further comprising a support ring element positioned to contact the outer surface of the sleeve portion of the sleeve assembly, the support ring element having an outer surface and an inner surface.

12. 12. The mechanical seal assembly of claim 11, wherein the gland assembly has a radially extending outer surface and an opposing radially extending inner surface, the body extending from an axially outer end to a radially inner end, a portion of the radially inner end forming an overhang portion, and the inner surface having a gland channel formed in the overhang portion.

13. the outer surface of the cover sealing element having a flat end surface portion with a radially inwardly extending end lip formed at a terminal region and a tapered end surface portion joined to the flat end surface portion; the inner surface of the cover sealing element comprises a first inner surface having a larger diameter than a second radially inward stepped inner surface, the first inner surface and the second inner surface being joined by a radially extending stepped wall surface having a wall channel formed therein; the wall channel including a wall lip overlying a portion of the wall channel; 13. The mechanical seal assembly of claim 12, wherein a bottom of the flange portion is mounted within the wall channel and the wall lip portion is mounted within and engages the engagement channel.

14. a cover channel formed in the first inner surface of the cover sealing element; 14. The mechanical seal assembly of claim 13, wherein the flange portion of the sleeve assembly has a projection extending outwardly from an outer circumferential surface of the flange portion for mounting within the cover channel.

15. 15. The mechanical seal assembly of claim 14, wherein the inner surface of the cover portion of the energizer sealing element has one or more protrusions formed thereon, and the stationary seal ring has an outer surface having a stator channel formed therein, the protrusions being configured to be mounted within the stator channel of the stationary seal ring when assembled.

16. The mechanical seal assembly of claim 15 , wherein the connection feature of the bend of the energizer sealing element includes a stepped lip.

17. the inner surface of the cover portion of the energizer sealing element includes a stepped wall portion including a first stepped wall surface transitioning to a second stepped wall surface; the support ring element has a first end disposed adjacent the stationary seal ring and an annular wall feature formed at the first end; 16. The mechanical seal assembly of claim 15, wherein in an assembled condition, the inner surface of the cover portion contacts the outer surface of the stationary seal ring and the second stepped wall surface of the cover portion contacts the annular wall feature of the support ring element.

18. 18. The mechanical seal assembly of claim 17, wherein in an assembled state, the connection feature of the bent portion of the energizer sealing element is configured to be disposed between the gland assembly and the fastener.

19. 18. The mechanical seal assembly of claim 17, wherein the bent portion of the energizer sealing element is disposed in a biased position when the energizer sealing element is coupled to the gland assembly and the stationary device, and the bent portion of the energizer sealing element forms a bent intermediate portion to bias the stationary seal ring when disposed in the biased position.

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