External Biased Secondary Seal in a Split Mechanical Seal

Abstract

The mechanical seal uses an axially movable spring holder plate that engages a sealing element, such as an O-ring, associated with a stationary seal ring. The stationary seal ring, in turn, can have a sealing surface that engages a sealing surface on a rotary seal ring. The rotary seal ring can also have a sealing element, such as an O-ring, associated with it. The O-rings are positioned in an unloaded position where they are not radially compressed and therefore their ends do not extend circumferentially beyond the end face of the holder or gland segment. The spring holder plate can be moved axially by tightening selected associated bolts. When moved axially, the spring holder plate moves the stationary seal ring and its associated O-ring inward along the axis, thus placing the O-ring in a loaded position where the O-ring is radially compressed.

Description

Technical Field

[0001] Related Applications This patent application claims priority to U.S. Provisional Patent Application No. 63 / 035,504, filed Jun. 5, 2020, entitled "Externally Energized Secondary Seal in a Split Mechanical Seal," which is incorporated herein by reference in its entirety.

Background Art

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

[0003] Split mechanical seals are used in a wide variety of mechanical devices to provide an airtight and fluid-tight seal. Typically, such mechanical seals are provided around a rotating shaft that is mounted within and protrudes from a stationary device. The mechanical seal is usually bolted to the stationary device at the shaft outlet, thus preventing pressurized process fluid from leaking out of the stationary device. Conventional split mechanical seals include face-type mechanical seals, which include a pair of seal rings that are concentrically arranged around the shaft and axially spaced from each other. Each seal ring has a plurality of sealing surfaces that are biased to seal against each other. Usually, one seal ring remains stationary while the other ring is coupled to and rotates with the shaft. The mechanical seal prevents pressurized process fluid from leaking into the external environment by biasing the sealing surfaces of the seal rings to seal against each other. Typically, the rotating seal ring is mounted within a holder assembly disposed within a chamber formed by a gland assembly. The holder assembly can comprise a pair of holder halves or segments that are fixed to each other by screws. Similarly, the gland assembly can comprise a pair of gland halves or segments that are also fixed to each other by screws. The seal rings are also often split into multiple segments, each segment having a pair of sealing surfaces, so that each ring forms a split ring that can be looped around the shaft without releasing one end of the shaft.

[0004] Conventional split mechanical seals include a rotating component and a stationary component that are bolted to the device to be sealed after being looped around the shaft. The rotating seal face is inserted into a rotating metal clamp after the segments are looped around the shaft. Next, when the stationary face segment and the gland segment are assembled, the split gland assembly is bolted to the pump housing. Alternatively, the stationary and rotating seal components can be pre-assembled into a sub-assembly and attached to the shaft.

[0005] The split mechanical seal for rotating and stationary bisected assemblies (e.g., four sub-assemblies) has metal parts, an elastomeric gasket and O-ring, and the split surfaces of the primary faces all lie in a straight line. For this reason, it is extremely difficult to reliably constrain all components to be aligned in a sealed state. For example, since the O-ring is compressed radially in the groove, its ends project and spread circumferentially, and there is a possibility of buckling during joining, and pinching by the metal or seal face parts occurs at the split position. Conventional methods of shifting the split positions of various parts within the rotating or stationary assembly cannot be used because the entire sub-assembly, rather than individual parts, is fixed around the shaft. This facilitates and speeds up the installation of the seal assembly into the equipment, but there is a possibility of misalignment of the parts and subsequent measurable leakage from the joints formed by the sealing components.

Summary of the Invention

[0006] Since this problem is particularly relevant to O-rings or other elastomeric split components, the present invention eliminates that problem. The present invention relates to a split mechanical seal that uses an axially movable spring holder plate. The spring holder plate can engage a sealing element such as an O-ring associated with a stator seal ring. The stationary seal ring can comprise a sealing surface that engages the sealing surface of a rotating seal ring. The rotating seal ring can also comprise a sealing element such as an O-ring associated therewith. Since the O-ring is not overly compressed radially, it is initially positioned in an unloaded position and does not extend circumferentially beyond the end face of the holder or ground section. The spring holder plate can be moved axially by tightening a selected associated bolt. When moved axially, the spring holder plate contacts the stationary seal ring and the O-ring associated therewith and moves them in an inward direction along the axis. The stationary seal ring then contacts the rotating seal ring and moves it in an inward direction along the axis, which in turn causes the rotating seal ring to move its associated O-ring in an inward direction along the axis. Thus, these O-rings are moved from the unloaded position to a loaded position where the O-ring is radially compressed.

[0007] The present invention relates to a mechanical seal for attachment to a housing provided with a shaft, the mechanical seal being a gland assembly configured to be attached to the housing and having an upper surface and an inner surface forming a gland attachment region, wherein a plurality of gland fastener holes are formed in the upper surface of the gland assembly; a holder assembly that forms a holder chamber and is disposed within the gland attachment region; a rotating seal ring disposed within the holder chamber of the holder assembly and having an outer surface; a rotor sealing element disposed around the outer surface of the rotating seal ring; a stationary seal ring disposed within the gland attachment region and having an outer surface; a stator sealing element disposed around the outer surface of the stationary seal ring; an axially movable spring holder plate having an upper surface, an opposite bottom surface, and a flange portion spaced radially inward, wherein a plurality of fastener openings are formed in the upper surface; a plurality of biasing clip assemblies configured to be attached around the spring holder plate, the plurality of biasing clip assemblies being configured to engage in a mating engagement with the stationary seal ring to couple the spring holder plate to the stationary seal ring; and a plurality of fasteners for attachment to the fastener openings and the gland fastener holes, the plurality of fasteners being for fixing the spring holder plate to the upper surface of the gland assembly. Further, the stator sealing element and the rotor sealing element can be disposed in a non-compressed state in the radial direction when in a first unloaded position, and the spring holder plate is axially movable when the plurality of fasteners are tightened, and axially moves the stator sealing element and the rotor sealing element to a radially compressed state at a second loaded position.

[0008] A plurality of spring holes are formed in the upper surface of the ground assembly, and a plurality of springs are attached to the plurality of spring holes. The holder assembly includes an inner surface formed with a holder movement stop groove, and the rotary seal ring includes a rotary movement stop groove formed in the outer surface. Further, the inner surface of the fixed seal ring includes a groove formed to couple to a part of each of the plurality of biasing clip assemblies, and the inner surface of the ground assembly includes an angled introduction surface. When the plurality of fasteners are tightened, the plurality of biasing clip assemblies apply an axially inward force to the fixed seal ring, and the fixed seal ring also applies an axially inward force to the rotary seal ring. The plurality of fasteners axially move the spring holder plate between the first unloaded position and the second loaded position. At the first unloaded position, the stator sealing element is disposed between the angled introduction surface and the outer surface of the fixed seal ring, and the rotor sealing element is disposed in the holder movement stop groove and the rotary movement stop groove, and the stator sealing element and the rotor sealing element are disposed in a state where they are not compressed in the radial direction. At the second loaded position, the stator sealing element is axially moved inward from the angled introduction surface by the flange portion of the spring holder plate and is disposed between the inner surface of the ground and the outer surface of the fixed seal ring. The rotor sealing element is displaced from the holder movement stop groove by the axially inward movement of the rotary seal ring so that the stator sealing element and the rotor sealing element are disposed in a radially compressed state.

[0009] According to the present invention, a plurality of recesses are formed on the upper surface of the spring holder plate, and a part of each of the plurality of biasing clip assemblies is received in a part of the recess. Further, the fixed seal ring has a plurality of spaced-apart recesses formed on its upper surface. Each of the plurality of biasing clip assemblies is an inner spring clip having a body, the body being formed at its first end and configured to engage a recess formed on the bottom surface of the spring holder plate, and an inner ridge portion, and a bent portion formed at a second opposite end and configured to engage one of the plurality of recesses formed on the upper surface of the fixed seal ring. The plurality of biasing clip assemblies further include an outer spring clip having a first end sized and configured to be attached to the body of the inner spring clip, and a second opposite end having a bent overhang portion sized and configured to engage the groove formed on the inner surface of the fixed seal ring.

[0010] The spring holder plate includes a body composed of first and second spring holder plate sections, each of the spring holder plate sections having first and second end faces, and surface features are formed on each of the end faces. The surface feature of the first end face of the first spring holder plate section is a protrusion, the surface feature of the second end face of the first spring holder plate section is an opening, the surface feature of the first end face of the second spring holder plate section is an opening configured to receive the protrusion of the first end face of the first spring plate holder section, and the surface feature of the second end face of the second spring holder plate section is a protrusion configured to be received in the opening formed on the second end face of the first spring holder plate section. Further, the surface features on the aligned and opposed seal surfaces of the sections are complementary to each other. The body further has a plurality of recesses formed on the upper surface.

[0011] The present invention also relates to a method for positioning a plurality of sealing elements within a mechanical seal. The mechanical seal is a gland assembly configured to be attached to the housing and having an upper surface and an inner surface forming a gland attachment region, wherein a plurality of gland fastener holes are formed in the upper surface of the gland assembly, the gland assembly; a holder assembly having an inner surface forming a holder chamber and disposed within the gland attachment region; a rotating seal ring disposed within the holder chamber of the holder assembly and having an inner surface and an opposite outer surface; a rotor sealing element disposed around the outer surface of the rotating seal ring; a stationary seal ring disposed within the gland attachment region and having an inner surface and an opposite outer surface; a stator sealing element disposed around the outer surface of the stationary seal ring; an axially movable spring holder plate having an upper surface, an opposite bottom surface, and a flange portion spaced radially inward, wherein a plurality of fastener openings are formed in the upper surface, the spring holder plate; a plurality of biasing clip assemblies configured to be attached around the spring holder plate and configured to engage in a mating engagement with the stationary seal ring for coupling the spring holder plate to the stationary seal ring; and a plurality of fasteners for attachment to the fastener openings and the gland fastener holes, the plurality of fasteners for fixing the spring holder plate to the upper surface of the gland assembly. The method of the present invention includes configuring the plurality of biasing clip assemblies to apply an axially inward force to the stationary seal ring when the plurality of fasteners are tightened, the stationary seal ring also applying an axially inward force to the rotating seal ring, the step of configuring the plurality of biasing clip assemblies; and configuring the spring holder plate to be axially movable.Specifically, the spring holder plate is disposed between the stator sealing element and an angled introduction surface formed on the inner surface of the ground assembly, and the outer surface of the fixed seal ring. The rotor sealing element is disposed in a no-load position where it is disposed in a holder movement stop groove formed on the inner surface of the holder assembly and a rotational movement stop groove formed on the outer surface of the rotational seal ring, and when the stator sealing element and the rotor sealing element are in the no-load position, they are not radially compressed. There is a no-load position, and a load position in which the stator sealing element is configured to be axially moved inward from the angled introduction surface by the flange portion of the spring holder plate, the stator sealing element being disposed between the inner surface of the ground and the outer surface of the fixed seal ring, and the rotor sealing element being configured to be displaced from the holder movement stop groove by an axially inward movement of the rotational seal ring. When in the load position, the stator sealing element and the rotor sealing element are in a radially compressed state.

[0012] The plurality of biasing clip assemblies include an inner spring clip having a body, the body having an inner ridge formed at its first end and configured to engage a recess formed in the bottom surface of the spring holder plate, and a bent portion formed at a second opposite end and configured to engage one of the plurality of recesses formed in the upper surface of the fixed seal ring. An inner spring clip; an outer spring clip having a first end sized and configured to be attached to the body of the inner spring clip and a second opposite end having a bent extension sized and configured to engage the groove formed in the inner surface of the fixed seal ring. The step of configuring the plurality of biasing clip assemblies to apply an axially inward force includes the step of applying an axially inward force to the fixed seal ring with the inner spring clip by contacting the recess formed in the upper surface of the fixed seal ring when the plurality of fasteners are tightened.

Brief Description of the Drawings

[0013] The above and other features and advantages of the present invention should be more fully understood by referring to the following detailed description and the accompanying drawings. Also, similar reference symbols in the drawings indicate similar members throughout the plurality of drawings. These drawings represent the principles of the present invention and, although not to scale, show relative dimensions.

Figure 1

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Figure 5

Figure 6

Best Mode for Carrying Out the Invention

[0014] The present invention provides a mechanical seal for achieving sealing in a rotating shaft or other suitable device. The present invention will be described in the following description in relation to the illustrated embodiments. Those skilled in the art should understand that the present invention can be implemented in a number of different applications and embodiments and is not particularly limited to the specific embodiments described herein.

[0015] As used herein, the terms "mechanical seal system", "mechanical seal", and "sealing assembly" are intended to include various types of mechanical fluid sealing systems, including single or integral seals, split seals, concentric seals, spiral seals, cartridge seals, and other known mechanical seals and sealing types and configurations.

[0016] The term "shaft" is intended to refer to any suitable device in a mechanical system to which a mechanical seal can be attached and includes shafts, rods, and other known devices. The shaft can move in any selected direction, such as a rotational direction or a reciprocating motion direction.

[0017] As used herein, the terms "axial" and "axially" refer to a direction generally parallel to the axis of any shaft. As used herein, the terms "radial" and "radially" refer to a direction generally perpendicular to the axis of any shaft. The terms "fluid" and "fluids" refer to liquids, gases, and combinations thereof.

[0018] As used herein, the terms "axially inner" or "axially internal" refer to the portion of the mechanical seal proximal to the stationary device and the stationary device using the mechanical seal. Conversely, the terms "axially outer" or "axially external" as used herein refer to the portion of the stationary device and seal assembly distal from the mechanical system.

[0019] As used herein, the term "radially inner" refers to the portion of the seal assembly proximal to any shaft. Conversely, the term "radially outer" as used herein indicates the portion of the mechanical seal distal from any shaft.

[0020] As used herein, the terms "stationary device", "stationary surface", and "ground" are intended to include any suitable stationary structure that houses the shaft or rod to which the seal is fixed.

[0021] FIG. 1-6C shows a mechanical seal 10 according to the teachings of the present invention. The illustrated mechanical seal 10 is preferably concentrically mounted around a shaft (not shown) and can be fixed to the outer wall of the fixed equipment by a fastener such as a bolt housed between the illustrated bolt tabs 14. The mechanical seal 10 fabricated according to the teachings of the present invention forms a fluid-tight seal, thus preventing process media such as hydraulic oil from escaping from the fixed equipment. This fluid-tight seal is achieved by a pair of sealing members illustrated as a rotating seal ring 20 and a stationary seal ring 30, and a pair of sealing members that form a seal therebetween. Each of the seal rings 21, 31 comprises a pair of seal ring half-cracks or segments, and further comprises smooth arcuate sealing surfaces 21, 31. The smooth arcuate sealing surfaces 21, 31 of each seal ring are biased to sealingly contact the corresponding sealing surface 21 or 31 of the other seal ring. Preferably, the seal rings 20, 30 are each divided into a pair of segments to facilitate installation as described below. The sealing surfaces 21, 31 of these seal rings form a fluid-tight seal operable under a wide range of operating conditions including vacuum conditions. The rotating seal ring 20 is mounted within a holder assembly 110, the holder assembly is mounted within a gland assembly 40, and the stationary seal ring 30 is mounted within the gland assembly 40.

[0022] As shown in FIGS. 2A-3B and 5B, the illustrated holder assembly 110 defines a space 111 that houses and holds the rotating seal ring 20. The holder assembly 110 can be divided to facilitate assembly and installation. In one embodiment, the holder assembly 110 includes a pair of arcuate holder segments 112 that are joined together to form an annular holder assembly 110. The holder assembly 110, or each arcuate holder segment 112 if this holder assembly is divided, comprises a radially outer surface 116 facing the gland assembly 40 and a first generally radially inner surface 124 (in addition to the radially innermost surface 138) that seals against the seal ring 20 and defines a space 111 that houses and holds the rotating seal ring 20.

[0023] Sealing elements such as O-ring 188 are concentrically looped around the rotary seal ring 20 to seal between the rotary seal ring 20 and the holder assembly 110. As shown, this O-ring 188 is preferably looped around the radially outer surface 184 of the axially inner portion of the rotary seal ring 20 and seals against the radially inner surface 124 of the holder assembly 110. The radially inner surface 124 of the holder assembly 110 includes a stop groove 189 for accommodating and retaining the O-ring 188 looped around the rotary seal ring 20, which facilitates the assembly and operation of the mechanical seal and holds the rotary seal ring 20 in an optimal position.

[0024] Other sealing members can seal the interface between different components of the mechanical seal 10. For example, a flat annular elastomeric gasket 60 can be used to seal the interface between the gland assembly 40 and the fixed equipment. Further, when the holder assembly 110 is split, a holder gasket 160 can be attached to the corresponding groove 158 to seal the holder sections 112 together. The holder / shaft elastomeric member is shown as O-ring 142 and is disposed within a holder groove 140 formed along the inner surface 138 to seal between the rotary seal ring holder assembly 110 and the shaft. The fixed seal ring / gland elastomeric member shown as O-ring 202 seals the interface between the fixed seal ring 30 and the gland assembly 40 and applies a radially inward pressure to the fixed seal ring 30. The gland gasket 76 is disposed within a gland gasket groove 70 (FIG. 3A) to form a seal between the gland halves when they are assembled together. Those skilled in the art should understand that this mechanical seal assembly 10 may be provided with any suitable means for sealing between different components.

[0025] Furthermore, the illustrated split mechanical seal 10 can include an anti-rotation mechanism (not shown), such as a pin or a flat surface element extending axially between the rotating seal ring 20 and the holder assembly 110, to prevent relative rotational movement between the rotating seal ring and the holder assembly 110. One of ordinary skill in the art should understand that suitable fasteners, such as bolts, can be used to fix the gland half and the holder half to each other. Some of the components of the mechanical seal 10 of the present invention are similar to the mechanical seal assemblies described in U.S. Patent Nos. 5,571,268 and 7,708,283, which are incorporated herein by reference.

[0026] The illustrated holder assembly 110 for mounting the rotating seal ring 20 is provided within the chamber 24 formed by the gland assembly 40 and is radially inwardly spaced therefrom. However, it should be understood that it is not necessary to dispose the holder assembly 110 within the gland assembly 40. Instead, the holder assembly 110 may be disposed axially spaced from the gland assembly 40. The holder assembly 110 further includes an inner stepped surface forming a second axially extending surface 133. A first wall 132 extending radially inwardly is formed between the radially inner surface 124 and the axially extending surface 133. As illustrated, the inner axially extending surface 133 and the radially innermost axially extending surface, i.e., the holder inner surface 138, define an axially innermost second wall 134 therebetween, which functions as the bottom of a cavity or a rotating seal ring receiving space 111 (FIG. 2B) for receiving the rotating seal ring 20.

[0027] In one embodiment, a sealing element or O-ring 188 that seals between the rotating seal ring 20 and the rotating seal ring holder 110 is received in a groove 189, such as a retaining groove, formed in the radially inner surface 124 of the holder assembly 110. The retaining groove 189 receives the radially outermost portion of the O-ring 188 and is dimensioned, positioned, and configured to position and attach the O-ring 188 to the holder assembly 110 without affecting operation during attachment. The retaining groove 189 preferably receives the O-ring 188 above the stepped wall 132. Alternatively, the retaining groove 189 receives the O-ring at another location between the holder assembly 110 and the rotating seal ring 20. A significant advantage of the retaining groove 189 and the placement of this groove in the radially inner surface 124 of the holder is that this reduces the amount of compression required to receive the O-ring 188 in this groove.

[0028] The illustrated rotary seal ring 20 includes an outer surface having several surfaces including a generally smooth arcuate inner surface 172, a first outer inclined surface 182 forming a skirt portion, a relatively flat outer surface 184, and an outer surface that is tapered or inclined axially inwardly 186. The rotary seal ring 20 also includes a smooth arcuate sealing surface 21 provided at the upper portion of the ring 20. As best shown in FIGS. 3B and 5B, the rotary seal ring stop groove 92 is formed in the flat outer surface 184 adjacent to the first inclined surface 182. The stop groove 92 formed in the rotary seal ring 20 serves at least two main functions. First, the groove 92 helps to position the rotary seal ring 20 in the correct position relative to the holder assembly 110. Second, the groove 92 allows the rotary seal ring to be pre-assembled within the holder assembly 110, which is done by forming a double capture groove (between the holder stop groove 188 and the rotary seal ring stop groove 92) that captures the O-ring 188 therebetween and at the same time holds the rotary seal ring 20 within the holder assembly 110. A generally rectangular notch (not shown) for attachment and coupling of components can be formed on the inner surface 172 of the rotary seal ring on a holder projection (not shown). The inner diameter of the inner surface 172 of the rotary seal ring is made larger than the diameter of the shaft to allow for circumferential attachment therearound. The diameter of the outer surface 184 of the rotary seal section is made the same as or slightly smaller than the diameter of the axially extending surface 133 of the holder section for attachment engagement to the holder assembly 110. The diameter of the outermost surface of the rotary seal ring 20 is smaller than the inner diameter of the inner surface 124 of the holder assembly 110. Those skilled in the art should readily understand, based on the teachings herein, that the rotary seal ring 20 can be provided with any suitable configuration for connecting to and sealing against another sealing element such as the stationary seal ring 30.

[0029] As shown in FIGS. 1-3B and 5A, the illustrated mechanical seal 10 also includes a gland assembly 40. The exemplary gland assembly 40 includes a pair of arcuate gland segments 41, 42 that are joined together to form an annular seal gland assembly 40. These gland segments 41, 42 are configured to engage with each other to facilitate the assembly and operation of the mechanical seal assembly 10. The gland assembly segments 41, 42 can use an engagement mechanism to facilitate the engagement of these gland segments. Each exemplary gland segment 41, 42 includes an inner surface with a first face 46 provided at an axially outer end with an angled introduction surface 52, and a second face 50 that extends radially outward from the first face 46 and is integrally formed and stepped. The first face 46 and the second face 50 together form a first coupling annular wall 48. The stepped second face 50 transitions to a surface 56 that is inclined radially inward. As described above, the inner surface of the gland segment formed by the faces 46, 48, 50, and 56 defines a space 24 for accommodating the holder assembly 110. Further, a pair of screw housings 80, 82 are integrally formed in each gland segment 41, 42. Each screw housing 80, 82 can include a transverse fastener receiving opening 84 formed substantially therethrough. A screw 90 for fixing the gland segments 41, 42 to each other is attached to the transverse opening 84. The gland assembly 40 also includes a housing gasket groove 58 formed along the inner bottom 59 of the gland assembly 40. The groove 58 accommodates a flat annular elastomeric gasket 60. The gland assembly 40 also includes an axially outer top surface 62 in which a plurality of spring holes 64 and a plurality of fastener holes 66 are formed. A spring element 80 is attached to the spring hole 64, and a suitable fastener such as a bolt 250 is attached to the fastener hole.

[0030] As shown in FIGS. 2A-3B, 5A and 6A-6C, and particularly FIG. 6A, the illustrated stationary seal ring 30 can similarly include a pair of arcuate seal ring segments, each of which is identical or generally identical to the other. The arcuate segments of the illustrated stationary seal ring can include a generally smooth arcuate inner surface 32 that extends parallel to the shaft axis and an opposite outer surface 36. As will be described in more detail later, a circumferentially extending recess or groove 33 sized and configured to receive a retaining portion of the biasing clip assembly 210 for attaching and retaining the stationary seal ring 30 to the ground holding plate 230 is formed along the inner wall of the inner surface 32. The groove 33 can be continuous or discontinuous. If discontinuous, the groove can be formed as a series of spaced-apart recesses along the inner surface 32. The outer surface 36 of the stationary seal ring 30 preferably includes an axially extending first outer surface 190 that terminates in an inclined receiving surface 192 that extends radially outward. The stationary seal ring 30 preferably includes an axially outer upper surface 194 and an opposite smooth axially inner arcuate ring sealing surface 31 provided at the bottom of the seal ring. A series of recesses or notches 196 sized and configured to selectively receive and / or engage at least a portion of the biasing clip assembly 210 are formed along the upper surface. This configuration facilitates aligning and receiving the stationary seal ring 30 within the chamber 24 and also functions as a mechanical obstruction to prevent the stationary seal ring 30 from rotating integrally with the shaft 12 and the rotating seal ring 20.

[0031] The inner diameter of the stationary seal ring 30 defined by the inner surface 32 is larger than the shaft diameter and, if desired, larger than the diameter of the inner surface 172 of the rotating seal ring 20, thus allowing their relative movement. Therefore, the stationary seal ring 30 remains stationary even when the shaft rotates. For example, an elastomeric sealing member such as the O-ring 202 applies a sufficient biasing force radially inward to bring the seal ring sectional sealing surface 35 into sealing contact with the other stationary seal ring section. Further, the O-ring 202 forms a fluid-tight and air-tight seal between the inner surface 46 of the gland assembly 40 and the stationary seal ring 30. When the O-ring 202 is in the load position, it is housed within a first mounting region 204 defined by the first gland surface 46, the annular wall 48, and the outer surface 190 of the stationary seal ring 30. In a preferred embodiment, the receiving surface 192 of the stationary seal ring 30 forms an angle of preferably about 30 degrees to about 60 degrees, and most preferably about 45 degrees, with respect to the outer surface 190 of the stationary seal ring. The stationary seal ring 30 is preferably made of a carbon material or a ceramic material such as alumina or silicon carbide.

[0032] Furthermore, the biasing assembly of the split mechanical seal 10 of the present invention, shown as the biasing clip assembly 210, acts as an axial biasing means by elastically supporting the stationary and rotating seal rings 20, 30. This is achieved by axially biasing these seal rings such that the stationary and rotating sealing surfaces 21 and 31 are in sealing contact with each other. As shown in FIGS. 2A - 3B, the seal rings 20, 30 are floatingly and non-rigidly supported in a floating relationship spaced from the rigid walls and surfaces of the gland and holder assemblies 40, 110. This floating and non-rigid support and spaced relationship allow the rotating seal section and the stationary seal section to move slightly in the radial and axial directions relative to the shaft 12, while the rotating sealing surface 21 is able to follow and seal in contact with the smooth arcuate sealing surface 31 of the stationary seal ring 30. Therefore, the sealing surfaces 21, 31 of the rotating and stationary seal rings self-align as a result of this floating action.

[0033] The mechanical seal 10 of the present invention preferably uses a series of biasing clip assemblies 210 attached to the axially outermost end of the gland assembly 40. Since these biasing clip assemblies 210 are identical, only one description of these clip assemblies is needed. The biasing clip assembly 210 preferably uses a pair of generally C-shaped spring clips formed as an inner spring clip 216 and an outer spring clip 218. The inner spring clip 216 includes a first lower portion having a ridge portion 220 that is received within a recess 242 of the spring holder plate 230. Engagement of the ridge portion 220 of the inner spring 216 with the recess 242 helps to fix the inner spring clip 216 there. Further, the inner spring clip 216 further includes, at an opposite end, a bent portion 222 that is received or disposed within a recess 196 formed in its upper surface 194 for applying an axial biasing force to the fixed seal ring 30. Thus, this bent portion 222 functions as an axial biasing member for applying an axial biasing force to the seal rings 20, 30. This axial biasing force, well known to those of ordinary skill in the art, is a force directed inwardly to bring the respective seal faces 21, 31 of the seal rings 20, 30 into sealing contact with each other.

[0034] The illustrated mechanical seal 10 also includes a spring holder plate 230 that is axially movable, as shown, for example, in FIGS. 2A - 4B. The illustrated spring holder plate 230 can be formed from a pair of plate sections 231, 233 that are connectable to each other. The spring holder plate 230 includes an annular body having an upper surface 232 with a plurality of notches or recesses 234 formed therein, the notches or recesses being circumferentially spaced along the periphery of the body. The upper surface 232 has a series of fastener receiving openings 236 for receiving fasteners such as bolts 250, for example. The spring holder plate 230 also includes a bottom surface 238 having a recess 242 formed adjacent to a flange portion 240 that extends axially. The recesses 234 and the recess 242 are configured to receive a portion of a biasing clip assembly 210, such as a selected portion of the inner spring clip 216. The spring holder plate sections have end faces 244 that are configured to mate with the end faces of the other spring holder plate section. One of the end faces 244 has a male - type projection or protrusion 246, and the other end face has a female - type hole or surface feature 248. The protrusion 246 is configured to be received within a corresponding hole 248 formed in the opposing end face 244 of the other spring holder plate section. Similarly, the hole 248 is configured to receive a corresponding protrusion formed in the opposing end face of the other holder plate section. The protrusion 246 and the hole 248 enable the holder plate sections to be mechanically coupled to each other. The spring holder plate 230 is sized and dimensioned such that the flange portion 240 is received between the inner surface 46 of the gland assembly 40 and the outer surface 190 of the stationary seal ring 30. When tightened by bolts 250, the spring holder plate 230 compresses the spring 86 and engages the O - ring 202. The O - ring 202 is pushed by the flange portion 240 into the attachment region 204 beyond the introduction surface 52 of the gland assembly 40. Similarly, the stationary seal ring 20 is axially pushed toward the rotating seal ring 20 by the biasing clip assembly 210.

[0035] The biasing clip assembly 210 of the mechanical seal 10 of the present invention includes an outer spring clip 218 adapted to be attached so as to cover the inner spring clip 216. The outer spring clip 218 includes a body having a generally circular first end portion 224 configured to be attached to and engage the outer surface of the inner spring clip 216, as most clearly shown in FIGS. 2B, 3B, and 6B. The outer spring clip 218 also includes an opposite end having a bent extension 228 that extends outward therefrom. The bent extension 228 is configured to overlap the bent portion 222 of the inner spring clip 216 and couple to and engage a recess 33 formed along the inner surface 32 of the fixed seal ring 30. The bent extension 228 of the outer spring clip 218 holds and attaches the fixed seal ring 30 to the ground assembly 40 by engaging the recess 33. Holding or attaching the fixed seal ring 30 to the ground assembly 40 allows the components of the mechanical seal 10 to be pre-assembled, thereby facilitating the installation of the split mechanical seal 10. One of ordinary skill in the art will readily understand that the inner and outer spring clips 216, 218 may have any suitable shape or configuration as long as they can engage the spring plate holder 230 and the fixed seal ring 30 to apply an axial biasing force to the fixed seal ring and the spring plate holder.

[0036] In assembly and operation, the mechanical seal 10 can be composed of four select split or sections with select seal elements that are pre-assembled to form sub-assembly units. For example, as shown in FIG. 5A, each ground section of the ground assembly 40 can be pre-assembled with select elements to form a ground sub-assembly unit 260, which includes a stationary seal ring 30, a spring holder plate 230, the corresponding half or section of the O-ring 202, and a selected number of biasing clip assemblies 210 corresponding to the number of recesses 234 formed in the upper surface 232 of the spring holder plate 230. The inner spring clip 216 is attached over and around the spring holder plate 230, and then the outer spring clip 218 is attached over or on top of the inner spring clip 216. The bent overhang 228 of the outer spring clip 218 engages a recess 33 formed along the inner surface 32 of the stationary seal ring 30, and the opposite end of this spring clip engages the spring holder plate 230. The spring 86 is attached to a spring hole 64 formed in the upper surface 62 of the ground assembly 40, and the spring holder plate 230 is fixed to the upper surface when a bolt 250 is disposed in a corresponding fastener hole 66.

[0037] Similarly, as shown in FIG. 5B, each holder section of the holder assembly 110 can be pre-assembled with selected elements to form the holder sub-assembly unit 270, which includes the corresponding halves or sections of the rotary seal ring 20 and the O-ring 188. The holder spacer element 126 is disposed within the holder space 111. The spacer element 126 helps to initially axially position selected seal components such as, for example, the O-ring 188 and, for example, the rotary seal ring 20, and to place them in the selected axial position to prevent accidental damage to these components. The holder spacer element is removed before the holder assembly is attached around the shaft 12. The O-ring 188 is disposed in the anti-movement groove 92 formed in the outer surface 184 of the rotary seal ring 20. When the O-ring 188 and the rotary seal ring section are disposed within the ground assembly 40, the O-ring 188 is positioned to be received within the anti-movement groove 189 formed in the inner surface 124 of the holder assembly 120. The anti-movement grooves 92, 189 act to capture and hold the O-ring 188 without applying excessive axial or radial loads to the O-ring. The ground and holder sub-assembly units 260, 270 can also include other sealing elements, such as, for example, other O-rings and sealing elements including the holder gasket 160, the ground gaskets 60, 76, and the O-ring 142. These sealing elements are also divided to fit within the sub-assembly units.

[0038] When assembling the holder and the grand sub-assembly unit with each other, when the O-ring is moved from the unloaded position to the loaded position, sealing elements such as O-rings 188 and 202 may be pinched. For example, since the O-ring is compressed in the radial direction, the O-ring spreads in the circumferential direction with the end of the O-ring section protruding, and there is a possibility of buckling during joining, and pinching by metal or seal face parts occurs at the split position. To prevent this occurrence, the present invention provides a selected assembly of components that form a loaded assembly, and this loaded assembly does not apply an excessive load to the O-rings 188 and 202 before the sub-assembly unit is assembled around the shaft 12, thus preventing the O-rings 188 and 202 from being pushed out beyond the end faces of the holder and the grand section.

[0039] With respect to the holder subassembly unit 270, each of the O-ring 188 segments is concentrically ring-mounted to the rotary seal segment 20 and is preferably disposed in contact with the rotary seal outer surfaces 182, 184 and the rotary seal ring movement stop groove 92 to form a pre-assembled rotary seal ring. The O-ring 188 and the rotary seal ring 20 are mounted within the holder assembly 110 such that the O-ring 188 is received within the movement stop grooves 189, 92 formed in the surfaces 124, 184. This prevents, reduces, or minimizes premature and unwanted loading on the O-ring 188 when the holder subassembly unit 270 is assembled. Thus, the end regions of the O-ring segments are not extruded beyond the end faces of the holder and ground segments. The pre-assembled holder units 270, 270 are then ring-mounted to the shaft 12. The rotary seal ring 20 can be rotatably coupled to the holder assembly 110 using a coupling mechanism such as a drive flat and can rotate relative to the holder assembly. This coupling mechanism can be disposed on either the holder assembly or the rotary seal ring, but in a preferred embodiment, it is disposed on both the rotary seal ring and the stationary seal ring. The movement stop groove 189 of the holder assembly 110 and the movement stop groove 92 of the rotary seal ring 20 receive and hold the O-ring 188 in an optimal position. The O-ring 188 applies a radially inward force sufficient to bring the axial seal surface 25 of the rotary seal segment into sealing contact with each other. Next, the holder segments are fixed to each other by tightening a screw 170 securely held within the fastener receiving port 164. Since the rotary seal ring segment is spaced from the inner surface 124 of the holder assembly and is non-rigidly supported therein by the O-ring 188, small radial and axial floating movements of the rotary seal ring 20 are possible. When disposed within the movement stop groove, the O-ring 188 is disposed in an unloaded position.

[0040] With respect to the grand pre-assembled unit 260, the O-ring 202 is disposed around the fixed seal ring 30 and then adjacent to the introduction surface 52 formed along the inner surface of the grand assembled part 40. The spring 86 is mounted in a corresponding spring hole 64 formed in the upper surface 62 of the grand assembled part 40. By partially tightening the bolt 250 into the fastener hole 66, the spring holder plate 230 is fixed to the upper surface 62 of the grand assembled part. The spring holder plate 230, the spring 86, and the bolt 250 can form a load assembly. A number of biasing inner clips 216 are first attached along the outer edge, i.e., the outer peripheral edge, of the upper surface 61 of the grand assembled part. The rib 220 at the first end of the inner spring clip 216 is attached to the recess 242 formed in the bottom surface 238 of the spring holder plate 230. The outer spring clip 218 includes a bent overhang 228 with an end or tip, and when attached to the inner spring clip 216, the end or tip is received in a groove 33 formed in the inner surface 32 of the fixed seal ring 30. The O-ring 202 is captured between the introduction surface 52 (FIG. 3B) and the outer surface 190 of the rotating seal ring 30.

[0041] As shown in FIGS. 2A and 2B, the ground subassembly unit 260 positions the O-ring 202 in the separated and unloaded position, and the holder subassembly unit 270 positions the O-ring 188 in the anti-movement grooves 188, 92 to place the O-ring 188 in the separated and unloaded position. Accordingly, the O-rings 188, 202 are not pushed out beyond the sealing surfaces of the holder and ground sections. When fully assembled, the operator can move the O-rings 188, 202 to the engaged and loaded positions by axially moving the spring holder plate 230 in the inward direction. For example, the operator can selectively tighten the bolt 250 using a suitable tool such as a wrench. When the bolt 250 is tightened, it acts to move the spring holder plate 230 in the inward direction along the axis against the biasing of the spring 86. The bottom surface of the flange portion 240 contacts the O-ring 202 and pushes the O-ring 202 into the space 204 in the inward direction along the axis beyond the angled introduction surface 52. Accordingly, the O-ring 202 is pushed into the region 204 (e.g., loaded) by radial compression, and the O-ring is arranged to make a sealing contact with the outer surface 190 of the fixed seal ring 30 and the inner surface or inner face 46 of the ground assembly 40. Thus, the O-ring 202 is arranged in the engaged and loaded position. Further, when the fixed seal ring 30 is coupled to the spring holder plate 230 by the biasing clip assembly 210, the axial movement of the spring holder plate 230 acts to press or move the fixed seal ring 30 in the inward direction along the axis. The fixed seal ring 30 contacts the rotating seal ring 20 via the sealing surfaces 21, 31, and thus pushes the rotating seal ring 20 in the inward direction along the axis. The axial movement of the rotating seal ring 20 pushes the O-ring 188 out of the anti-movement groove 189 formed in the inner surface 124 of the holder assembly 110. When the O-ring 189 is taken out of the anti-movement groove 189, it is compressed (e.g., loaded) between the inner surface 124 of the holder assembly 110 and the outer surface 184 of the rotating seal ring 20. Thus, the O-ring 188 is accommodated in the anti-movement groove 92 both when in the loaded position and when in the unloaded position.The anti-rotation grooves 189 and 92 preferably have a curved cross-section and are separate grooves sized and configured to receive the O-rings 188.

[0042] Thus, using the illustrated load assembly, the O-rings 202, 188 can be axially moved to their engagement / load positions where they are radially compressed. These O-rings are compressed after the ground and holder sub-assembly units are assembled and fixed to the stationary device around the shaft. According to the load assembly of the present invention, when the sub-assembly units are fixed to each other, prior to assembly, the O-rings are prevented from being pushed out beyond the end faces at locations where the O-rings can be pinched. Since the ground and holder surfaces defining the regions for attaching the O-rings 202, 188 are in contact with each other before the O-rings are radially compressed in the sealing position, there are no protruding ends of the O-ring sections and there is no possibility of poor attachment of the sealing element.

[0043] The spring holder plate 230 further includes sections 231, 233 that are fixed to each other using male and female mechanical couplings. The spring holder plate 230 serves to hold the rotating and fixed O-rings 188, 202 in a free or unloaded position while the ground and holder sub-assembly units 260, 270 are being fixed around the shaft, before being tightened by an operator. The pre-assembled sub-assembly units 260, 270 allow for the sequential attachment of these units. Specifically, the holder sub-assembly unit 270 (e.g., the rotating sub-assembly unit) is fixed to the shaft 12, and then the ground sub-assembly unit 260 (e.g., the stationary sub-assembly unit) is fixed to the stationary device around the rotating component. The axial movement of the spring holder plate 230 via the bolts 250 pushes the seal surfaces 21, 31 and the rotating and fixed O-rings 188, 202 into their operating positions. Thus, a single element can be used to displace the O-rings 188, 202 from a non-radially compressed state (e.g., unloaded position) to a compressed and energized state (e.g., load position).

[0044] Therefore, it should be understood that the present invention can effectively achieve the above-described objects, which are included in the objects made clear from the description so far. Since it is possible to make certain changes to the above configuration without departing from the scope of the present invention, all matters included in this description or shown in the accompanying drawings are intended to be construed as illustrative and not in a limiting sense.

[0045] Furthermore, the following claims are to be construed as covering all general and specific features of the present invention described herein, as well as all statements regarding the scope of the present invention.

[0046] Although the present invention has been described, those desiring to claim it as new and secure it by a patent are as follows.

Claims

1. A mechanical seal for attachment to a housing having a shaft, a gland assembly configured to be attached to the housing, the gland assembly having an upper surface and an inner surface forming a gland attachment region, and a plurality of gland fastener holes formed in the upper surface of the gland assembly, the gland assembly, a holder assembly forming a holder chamber and disposed within the gland attachment region, a rotating seal ring disposed within the holder chamber of the holder assembly and having an outer surface, a rotor sealing element disposed around the outer surface of the rotating seal ring, a stationary seal ring disposed within the gland attachment region and having an outer surface, a stator sealing element disposed around the outer surface of the stationary seal ring, an axially movable spring holder plate having an upper surface, an opposite bottom surface, and a flange portion spaced radially inward, and a plurality of fastener openings formed in the upper surface, the spring holder plate, a plurality of biasing clip assemblies configured to be attached around the spring holder plate, the plurality of biasing clip assemblies configured to fit and engage with the stationary seal ring to couple the spring holder plate to the stationary seal ring, a plurality of fasteners for attachment to the fastener openings and the gland fastener holes, the plurality of fasteners for fixing the spring holder plate to the upper surface of the gland assembly, including, the stator sealing element and the rotor sealing element being disposed in a non-radially compressed state when in a first unloaded position, the spring holder plate being axially movable when the plurality of fasteners are tightened, and axially moving the stator sealing element and the rotor sealing element to a radially compressed state when in a second loaded position, the mechanical seal.

2. The mechanical seal according to claim 1, further comprising a plurality of springs for attachment to the plurality of spring holes formed in the upper surface of the gland assembly.

3. The mechanical seal according to claim 2, wherein the holder assembly has an inner surface formed with a holder movement stop groove.

4. The rotary seal ring includes a rotation prevention groove formed on the outer surface, the mechanical seal according to claim 3.

5. The inner surface of the fixed seal ring is provided with a groove formed to engage with a part of each of the plurality of biasing clip assemblies. The inner surface of the gland assembly is provided with an angled introduction surface. When the plurality of fasteners are tightened, the plurality of biasing clip assemblies apply an axially inward force to the fixed seal ring, and the fixed seal ring also applies an axially inward force to the rotary seal ring. The plurality of fasteners cause the spring holder plate to: The first unloaded position, where the stator sealing element is disposed between the angled introduction surface and the outer surface of the fixed seal ring, and the rotor sealing element is disposed in the holder movement prevention groove and the rotation prevention groove, and the stator sealing element and the rotor sealing element are disposed in a state where they are not compressed in the radial direction; the first unloaded position, The second loaded position, where the stator sealing element is moved axially inward from the angled introduction surface by the flange portion of the spring holder plate and is disposed between the inner surface of the gland assembly and the outer surface of the fixed seal ring. The rotor sealing element is displaced from the holder movement prevention groove by the axial inward movement of the rotary seal ring so that the stator sealing element and the rotor sealing element are disposed in a state where they are compressed in the radial direction. Move between the second loaded position, the mechanical seal according to claim 4.

6. The mechanical seal according to claim 4, wherein a plurality of recesses are formed in the upper surface of the spring holder plate.

7. The mechanical seal according to claim 6, wherein a part of each of the plurality of biasing clip assemblies is received in a part of the recess.

8. The mechanical seal according to claim 6, wherein the fixed seal ring is provided with a plurality of spaced recesses formed on its upper surface.

9. Each of the plurality of biasing clip assemblies is an inner spring clip having a body, and the body is formed at its first end and is configured to engage with a recess formed on the bottom surface of the spring holder plate, an inner ridge portion An inner spring clip including a bent portion formed at a second opposite end and configured to engage with one of the plurality of recesses formed on the upper surface of the fixed seal ring. An outer spring clip having a first end sized and configured to be attached to the body of the inner spring clip and a second opposite end sized and configured to engage with the groove formed on the inner surface of the fixed seal ring, the mechanical seal according to claim 8.

10. The spring holder plate includes a body composed of a first and a second spring holder plate section, each of the spring holder plate sections having a first and a second end face, and surface features are formed on each of the end faces. The surface feature on the first end face of the first spring holder plate section is a protrusion, and the surface feature on the second end face of the first spring holder plate section is an opening. The surface feature on the first end face of the second spring holder plate section is an opening configured to receive the protrusion on the first end face of the first spring plate holder section, and the surface feature on the second end face of the second spring holder plate section is a protrusion configured to be received in the opening formed on the second end face of the first spring holder plate section, the mechanical seal according to claim 1.

11. The mechanical seal according to claim 10, wherein a plurality of recesses are formed on the upper surface of the body.

12. A method for positioning a plurality of sealing elements within a mechanical seal, A gland assembly configured to be attached to a housing and having an upper surface and an inner surface forming a gland attachment region, wherein a plurality of gland fastener holes are formed on the upper surface of the gland assembly. A holder assembly having an inner surface forming a holder chamber and disposed within the gland attachment region. A rotating seal ring disposed within the holder chamber of the holder assembly and having an inner surface and an opposite outer surface. A rotor sealing element disposed around the outer surface of the rotating seal ring. A fixed seal ring disposed within the gland attachment region and having an inner surface and an opposite outer surface. A stator sealing element disposed around the outer surface of the fixed seal ring; An axially movable spring holder plate having an upper surface, an opposite bottom surface, and a flange portion spaced radially inward, the upper surface having a plurality of fastener openings formed therein; A plurality of biasing clip assemblies configured to be attached around the spring holder plate, the plurality of biasing clip assemblies configured to engage in a mating engagement with the fixed seal ring for coupling the spring holder plate to the fixed seal ring; A plurality of fasteners for attachment to the fastener openings and the ground fastener holes, the plurality of fasteners for fixing the spring holder plate to the upper surface of the ground assembly; The method, when the plurality of fasteners are tightened; Configuring the plurality of biasing clip assemblies to apply an axially inward force to the fixed seal ring, the fixed seal ring also applying an axially inward force to the rotating seal ring, the step of configuring the plurality of biasing clip assemblies; The spring holder plate is: A no-load position in which the stator sealing element is disposed between an angled introduction surface formed on the inner surface of the ground assembly and the outer surface of the fixed seal ring, and the rotor sealing element is disposed in a holder movement stop groove formed on the inner surface of the holder assembly and a rotational movement stop groove formed on the outer surface of the rotating seal ring, and the stator sealing element and the rotor sealing element are not compressed radially when in the no-load position; A load position in which the stator sealing element is configured to be axially moved inward from the angled introduction surface by the flange portion of the spring holder plate, the stator sealing element being disposed between the inner surface of the ground and the outer surface of the fixed seal ring, and the rotor sealing element being configured to be displaced from the holder movement stop groove by an axially inward movement of the rotating seal ring, and configuring the spring holder plate to axially move between the no-load position and the load position, wherein when in the load position, the stator sealing element and the rotor sealing element are in a radially compressed state. Claim 13 each of the plurality of biasing clip assemblies is an inner spring clip having a body, the body including an inner ridge formed at its first end and configured to engage a recess formed in the bottom surface of the spring holder plate, and a bent portion formed at a second, opposite end and configured to engage one of a plurality of recesses formed in the upper surface of the fixed seal ring, the inner spring clip including an outer spring clip having a first end sized and configured to be attached to the body of the inner spring clip and a second, opposite end having a bent extension sized and configured to engage the groove formed in the inner surface of the fixed seal ring, the step of configuring the plurality of biasing clip assemblies to apply an axially inward force, when the plurality of fasteners are tightened, includes applying an axially inward force to the fixed seal ring with the inner spring clip by contacting the recess formed in the upper surface of the fixed seal ring, the method of claim 12.

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