Flexible sealing membrane and sealing assembly for a rotating shaft device

Abstract

A mechanical seal assembly (10) suitable for use about a rotating shaft of a rotating device and having first (36) and second (30) seal rings. The assembly (10) further includes an annular carrier (200) configured to be fixed to a housing of the rotating device, the annular carrier (200) having a base portion (202) and a removable end portion (204). The assembly (10) further includes an annular flexible seal membrane (100). The membrane (100) includes an outer portion (102) configured to be disposed between the first seal ring (36) and a biasing mechanism (500) and configured to move axially relative to the rotating shaft (12). The membrane (100) further includes an inner portion (104) surrounded by the outer portion (102) and positioned between the base portion (202) and the removable end portion (204) of the annular carrier (200), the base portion (202) and the removable end portion (204) retaining the inner portion (104) fixed relative to the annular carrier (200) as the outer portion (102) moves relative to the rotating shaft (12).

Description

[0001] International priority This application claims priority to U.S. Provisional Application No. 63 / 109434, filed November 4, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to a rotating shaft device having a mechanical seal assembly that provides a seal between the housing and the rotating shaft of the rotating shaft device. More specifically, this invention relates to such rotating shaft devices and sealing assemblies including an auxiliary sealing diaphragm. Background Technology

[0003] Mechanical seals are used to provide a seal between the rotating shaft and a stationary housing in pumps, compressors, turbines, or other rotating machinery. Face mechanical seals typically consist of a main sealing interface defined by two rotatable sealing surfaces, or otherwise defined by so-called "dynamic rings" and "stationary rings." Frictional wear between the sealing surfaces can create gaps between them, leading to excessive leakage. Therefore, considering this wear issue, face seals require periodic adjustments to maintain the axially movable sealing element in the proper or axial position (also known as "seal height").

[0004] Various biasing mechanisms can be used to provide a closing force that automatically adapts to wear. These biasing mechanisms include single and multiple conical springs as well as metal bellows.

[0005] Push-type sealing assemblies include a dynamic auxiliary seal (such as an O-ring) to provide a seal between the shaft and the sealing member. The dynamic auxiliary seal in a push-type seal is typically configured to move axially together with the axially moving sealing member / dynamic ring. This axial movement relative to the shaft can cause wear or tearing of the auxiliary seal due to friction.

[0006] Non-propellant seals typically include an auxiliary shaft seal that does not move axially relative to the shaft, such as an O-ring (often used with metal bellows seals) or a resilient bellows, like... Figure 1One embodiment is shown. The illustrated mechanical seal includes an elastic bellows that can rotate with the shaft relative to the housing under a driving force. A non-propelled seal reduces torque stress on the bellows, which is designed to balance opening and closing forces on the sealing surface through contraction and expansion. However, under high pressure conditions, such as gauge pressures above approximately 70 bar (g), the shaft itself can translate axially. This generates an axial load on the elastic bellows, causing rigid collapse of the elastomer, as shown in the enlarged view (where the brighter areas represent areas with higher pressure). This axial stiffness prevents the bellows from effectively counteracting the closing force provided by the offset member, leading to excessive end-face pressure, frictional wear, and ultimately, seal failure.

[0007] The ongoing demand for increased productivity, reliability, durability, and evolving containment requirements in pumps and other rotating shaft equipment necessitates continuous efforts to develop new sealing assemblies. In particular, there is a need to operate mechanical seals at higher internal pressures. This invention relates to improvements in sealing technology to meet these demands. Summary of the Invention

[0008] The embodiments of this disclosure, by providing a combination of a mechanical seal assembly and a flexible sealing membrane for rotating shaft devices, can meet the needs of mechanical seals to perform sealing operations at higher internal pressures.

[0009] The flexible sealing membrane is typically implemented as a ring, comprising an outer portion extending substantially radially, which can be pushed into an axially movable ring by sealing elements, such as multiple axially spaced springs. This first portion is typically non-collapsible and surrounds an inner portion that is thinner than the outer portion. In operation, movement of the moving ring relative to the shaft will cause deflection of the outer portion relative to the inner portion, and in some cases, also cause deflection of the rotating shaft of a rotating shaft machine.

[0010] In one embodiment, the sealing membrane comprises a flexible elastomer.

[0011] In one embodiment, a mechanical seal assembly is disclosed, adaptable to a device surrounding a rotational shaft of a rotating device. The mechanical seal assembly includes a first sealing ring that is axially movable relative to the rotational shaft during operation, and a second sealing ring that is axially fixed relative to the rotational shaft during operation. The assembly also includes an annular support member disposed fixed to a housing of the rotating device, the annular support member having a base portion and a detachable end portion. The axially movable first sealing ring is proximal to the annular support member and is axially movable relative to the annular support member in response to axial movement of the rotational shaft and the axially fixed second sealing ring, and the axially movable first sealing ring has an axially movable sealing surface that engages with the axially fixed sealing surface of the axially fixed second sealing ring. The assembly also includes a biasing mechanism and an annular flexible sealing diaphragm, the biasing mechanism pushing the axially movable first sealing ring toward the axially fixed second sealing ring, thereby engaging the axially movable sealing surface to the axially fixed sealing surface using a closing force.

[0012] The sealing membrane disclosed in this invention can be any type of membrane. For example, the sealing membrane may include an outer portion disposed between an axially movable first sealing ring and a biasing mechanism, the outer portion being axially movable relative to a rotation axis. The membrane may also include an inner portion surrounded by the outer portion, the inner portion being located between a base portion of the annular support member and a detachable end portion. In at least one embodiment, when the outer portion moves relative to the annular support member, the base portion and the detachable end portion keep the inner portion fixed relative to the annular support member.

[0013] In any of the foregoing embodiments, the base portion has an upper surface positioned close to the outer portion of the annular flexible sealing membrane, in which a recess is formed.

[0014] In any of the foregoing or alternative embodiments, the detachable end portion has an upper surface positioned close to the outer portion of the annular flexible sealing membrane, in which a recess is formed.

[0015] In any of the foregoing or alternative embodiments, the outer portion has a thicker cross-section than the inner portion.

[0016] In any of the foregoing or alternative embodiments, the biasing mechanism includes an axially movable annular retainer near the outer portion and a plurality of radially spaced spring members disposed between the annular support and the annular retainer.

[0017] In any of the foregoing or alternative embodiments, the component further includes a rotating sleeve operably coupled to a rotating shaft for rotation therewith, and wherein an axially fixed second sealing ring is operably coupled to the sleeve. In any of the foregoing or alternative embodiments, the axially fixed second sealing ring is operably coupled to the sleeve via a plurality of pins.

[0018] In any of the foregoing or alternative embodiments, the sealing membrane comprises a flexible elastomer.

[0019] In any of the foregoing or alternative embodiments, the sealing assembly further includes an anti-compression ring within a groove of a first sealing ring that is axially movable.

[0020] In any of the foregoing or alternative embodiments, the anti-compression ring may comprise a flexible elastomer material with a hardness greater than that of the sealing membrane.

[0021] In any of the foregoing or alternative embodiments, the sealing assembly further includes a sealing plate adapted for connection to the housing, and a carrier is connected to the sealing plate.

[0022] The above description is not intended to depict an embodiment of every illustration or every subject matter. The following figures and detailed description will illustrate the various embodiments in more detail. Attached Figure Description

[0023] A more comprehensive understanding of the subject matter of this document can be achieved by considering the following detailed description of various embodiments in conjunction with the accompanying drawings, wherein: Figure 1 It is a cross-sectional view of a part of a sealing assembly in the prior art and an enlarged cross-sectional view of an elastic bellows; Figure 2 It is a cross-sectional view depicting a portion of a sealing assembly according to one embodiment; Figure 3A is a top view of a sealing film according to one embodiment; Figure 3B is an enlarged cross-sectional view depicting a sealing film according to one embodiment; Figure 4 This is a more detailed depiction of a portion of the seal shown in Figures 3A and 3B; Figure 5A and Figure 5B A schematic diagram showing the deflection of the outer portion of the membrane at two different motion positions is shown; Figure 6 A cross-sectional view of a portion of a sealing assembly depicted according to one embodiment is shown; and Figure 7 A cross-sectional view of a portion of a sealing assembly depicted according to one embodiment is shown.

[0024] While the various embodiments are susceptible to various modifications and alternatives, the embodiments illustrated in the accompanying drawings have been shown in detail, and their details will be described in detail thereto. However, it should be understood that the purpose is not to limit the claimed invention to the specific embodiments described. Rather, the invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter defined by the claims. Detailed Implementation

[0025] Figure 2 A cross-sectional view of a portion of a sealing assembly 10 according to an embodiment of the present disclosure is depicted. The sealing assembly 10 includes a flexible sealing membrane 100 shown together with a rotating shaft device (e.g., a pump, mixer, agitator, stirrer, compressor, blower, and fan).

[0026] The sealing assembly 10 seals the rotating and axially extending shaft 12 of the rotating shaft device, which is common for this type of sealing assembly. The sealing assembly 10 can provide a seal for the processing chamber 14 within the interior range of the sealing assembly 10 relative to the surrounding environment 16.

[0027] The sealing assembly 10 may be coaxially disposed in a bore defined by an annular housing 18 (e.g., the body of a rotating machine) coaxial with the shaft 12. Various fixed (or non-rotating) components of the sealing assembly 10 may be operatively coupled to the housing 18 or other elements, such as a sealing plate typically indicated by reference numeral 20, which may also be operatively coupled to the housing 18.

[0028] Various rotating components are operatively coupled to shaft 12 to rotate with it. An annular sleeve member 22 is fixed to shaft 12 to rotate with it. An annular flange structure 26 extends outward in the radial direction of sleeve member 22 at its end adjacent to processing chamber 14.

[0029] An axially fixed sealing ring 30 (or stationary ring) is mounted on the surface of the annular flange structure 26 remote from the processing chamber 14 to rotate with it. An annular O-ring 32 provides a resilient auxiliary seal between the sleeve member 22 and the axially fixed sealing ring 30; in embodiments, additional auxiliary sealing O-rings may be provided. The axially fixed sealing ring 30 includes an outer sealing surface 50.

[0030] An axially movable sealing ring 36 (or a moving ring) is disposed outside and adjacent to the axially fixed sealing ring 30. The axially movable sealing ring 36 includes an inner sealing surface 52. The inner sealing surface 52 is adjacent to the outer sealing surface 50.

[0031] Although, as described above, the axially movable sealing ring 36 is stationary and the axially fixed sealing ring 30 is rotatable, in embodiments, relative axial movement can be provided either by rotation or by the stationary sealing ring.

[0032] Inlet 40 is defined within housing 18 and / or sealing plate 20 to provide sealing lubricant (not shown) to sealing surfaces 50 and 52.

[0033] In the following discussion, direction A will be referred to as the outward direction (the opposite direction is the inward direction), and direction B will be referred to as the radial outward direction.

[0034] The sealing membrane 100 may have a generally dumbbell-shaped cross-section, including an outer portion 102 and an inner portion 104 surrounded by the outer portion 102. The inner surface of the outer portion 102 may abut against the outer surface of the axially movable sealing ring 36, thereby creating a pressure-tight seal. When the axially movable ring 36 moves, the outer portion 102 may tilt or otherwise move relative to the inner portion. As shown in FIG3B, the inner portion 104 may have a thinner cross-section than the outer portion 102 to enable this relative movement.

[0035] The internal portion 104 is fixed to and held by the annular support 200. More specifically, the annular support 200 may be connected to the housing 18 or the sealing plate 20 and may provide a stable and immovable base for the biasing mechanism 500.

[0036] The annular carrier 200 shown in the figure includes two parts: a primary (or base) portion 202 and a detachable end portion 204, wherein the detachable end portion 204 can be attached to the base portion 202 by means of, for example, a fastener 203. In an embodiment, the annular carrier 200 and the fastener 203 may be made of steel or stainless steel.

[0037] The sealing membrane 100 is held in place by adjusting the dimensions and arrangement of the base portion 202 and the removable end portion 204. As shown, the inner portion of the sealing membrane is mounted between the base portion 202 and the removable end portion 204, in which way the inner portion 204 is immovable relative to the base portion 202 or the housing 18. More details about the sealing membrane 100 will be discussed below.

[0038] An annular anti-compression ring 220 may be disposed in an annular groove of an axially movable sealing ring 36, and adjacent to or near the outer portion 104 or other portions of the sealing member 100 and the annular support member 200. The annular anti-compression ring 220 may comprise an elastomer with a specific hardness greater than that of the sealing membrane 100, such as carbon-filled polytetrafluoroethylene (PTFE) with a hardness of 50 to 55 (Shore type D). In one embodiment, since compression is most likely to occur at the equilibrium diameter of the seal, the inner diameter of the anti-compression ring 220 may be set as the equilibrium diameter of the sealing assembly 10.

[0039] The biasing mechanism 500 abuts the outer portion 102 of the sealing member 100. The biasing mechanism 500 includes an axially movable annular retainer 502, a fixed support member 200, and one or more biasing members 506 spanning between them. The annular retainer 502 is positioned close to the outer portion 102. The annular retainer 502 has a protrusion 508 extending axially inwardly outside the outer diameter of the outer portion 102. The protrusion 508 is radially spaced from the outer surface of the outer portion 102. The main base portion of the fixed support member 200 can be axially and rotatably secured to the sealing plate 20 by one or more pins 510, but other securing mechanisms may also be used. The biasing members 506 may include one or more radially spaced springs, but other biasing mechanisms known in the art may also be used. In an embodiment, one or both of the annular retainer 502 and the base portion 202 may include holes adapted to receive at least a portion of each biasing member 506, such that the biasing member 506 is partially located within the annular retainer 502 and the base portion 202.

[0040] It will be understood by those skilled in the art that Figure 2 The configuration shown includes components that may be changed or removed in other sealing assembly embodiments. Furthermore, more or fewer components may be incorporated in other embodiments of the sealing assembly according to this disclosure.

[0041] During operation, rotation of shaft 12 drives the sleeve component and axially fixed sealing ring 30 to rotate relative to axially movable sealing ring 36. Sealing lubricant (not shown) can be supplied to seal 10 through one or more inlets 40 provided on housing 18 to lubricate the seals of sealing surfaces 50 and 52 and to generate a pressure gradient on sealing surfaces 50 and 52.

[0042] The pressure gradient and hydraulic pressure generated by the relative rotation of sealing surfaces 50 and 52 produce an opening force, which pushes the axially movable sealing ring 36 axially outward (direction A) from the axially fixed sealing ring 30. Similarly, the biasing mechanism 500 can generate a closing force, which pushes the axially movable sealing ring 36 inward toward the axially fixed sealing ring 30.

[0043] Those skilled in the art will understand that the closing force at the sealing interface can be calculated from the closing area (AC), the opening area (AO), the outer diameter (OD) of the stationary toroidal surface, the inner diameter (ID) of the stationary toroidal surface, and the equilibrium diameter (BD), as detailed below:

[0044]

[0045] The outer portion 102 can move axially and radially (or otherwise translate) based on the associated closing and opening forces and the axial translation of the shaft itself, such that the closing force applied to the axially displaceable sealing ring 36 is constant, regardless of the position of the outer portion 102.

[0046] Figures 3A and 3B respectively show an example of a sealing member 100 according to one embodiment and its cross-section. The sealing member 100 includes an outer portion 102 and an inner portion 104. The inner portion 104 has a first thickness T1 and a second thickness T2. In one embodiment, T1 is greater than T2. ​​In another embodiment, T1 is three times larger than T2.

[0047] As described above and further refer to Figure 2 The movement of the movable sealing ring 36 will cause the outer portion 102 to move axially inward / outward. When the inner portion is held axially fixed relative to the housing 18 by the fixed / annular support 200, the thickness difference between the inner portion 102 and the outer portion 104 will allow this bending.

[0048] Reference Figure 2 and Figure 4 The annular support member 200 includes one or more recesses formed on its radially outward surface to allow movement of the outer portion 102 of the sealing member 100. Specifically, the base portion 202 of the annular support member 200 includes an outer surface 210 having a recess 210a formed therein, which is positioned near the outer portion 102 during operation. Similarly, the detachable end portion 204 of the annular support member 200 includes an outer surface 208 having a recess 208a formed therein, which is positioned near or adjacent to the outer portion 102 during operation. These recesses are optional, but they allow for easier relative movement of the outer portion 102 relative to the inner portion 104 during movement of the moving ring 36. The recesses 208a / 210a may individually or collectively define the flange travel region 214. Furthermore, in some embodiments, only one recess may be provided.

[0049] For example, refer to Figure 5A and Figure 5BThe outer part 102 can move axially inward (direction A) relative to the inner part 104, such as... Figure 5A As shown. Figure 5B This illustrates a case where the outer portion 102 has moved axially outward (direction A') relative to the inner portion 104. In both cases, the inner portion 104 is held in a substantially constant position because it is held between the base portion 202 of the annular support 200 and the detachable end portion 204 (see...). Figure 2 ).

[0050] Referring back to Figures 3A and 3B, the sealing member 100 includes a central hole 105 formed in the interior 104. The central hole 105 is sized and positioned such that it surrounds the shaft 12 and optionally the sleeve member 20. The sealing member 100 may include one or more fastener holes 302 through which fasteners can pass to connect the base portion 202 of the annular carrier 200 and the removable end portion 204. It should be understood that when the outer portion 102 moves, the base portion 202 and the removable end portion 204 keep the inner portion 104 fixed relative to the annular carrier 200. This movement can be relative to the rotation shaft 12. Of course, the end region of the inner portion 104 may move slightly with the outer portion 102, but the vast majority of the inner portion 104 remains stationary, and this vast majority should be included when describing the inner portion 104 as stationary, fixed, or otherwise immobile.

[0051] As mentioned above, recesses 208a / 210a are optional and can be omitted, such as Figure 6 As shown. Furthermore, in some embodiments, such as Figure 7 As shown, the compression ring 220 can be omitted. It should be noted that the compression ring can be omitted in the absence of a compression ring and a recess.

[0052] During the seal's lifespan, sealing surfaces 50 and 52 will wear relative to each other. Because the sealing membrane 100 can move inward toward the processing chamber 14 and outward away from the processing chamber 14 during the seal's lifespan, the sealing membrane 100 helps maintain a proper sealing clearance. When the outer portion 102 of the sealing membrane 100 moves inward, hydraulic pressure prevents the axially movable sealing ring 36 from contacting the axially fixed sealing ring 30. When hydraulic pressure cannot be provided, the biasing mechanism 500 can be used to set the working height of the seal and press the outer portion 102 of the sealing membrane 100 against one end of the axially movable sealing ring 36 (relative to the distal end of the processing chamber and the opposite side of the sealing surface 52) (forming a seal). In some embodiments, due to the presence of the recess, the axial movement of the sealing membrane 100 does not change the vertical force, and the closing force at the interface of sealing surfaces 50 and 52 is unaffected.

[0053] The maximum axial outward translation of the outer portion 102 and the annular retainer 502 may be defined by the gap provided between the outer surface of the annular retainer 502 and the inner surface 205 of the carrier 200, or by the compression limit of the biasing member 506. In an embodiment, limiting the translation of the outer portion 102 prevents folding or other collapse of the sealing member 100.

[0054] Furthermore, since the outer portion 102 is held in a radially extending position by the axially movable sealing ring 36 and retainer 502, and the inner portion 104 is held in an axially extending position by the base portion 202 of the annular support 200 and the detachable end portion 204, the sealing member 100 is non-foldable.

[0055] Various embodiments of systems, devices, and methods have been described herein. These embodiments are given by way of example only and are not intended to limit the scope of the claimed invention. Furthermore, it should be understood that the various features of the described embodiments can be combined in various ways to produce numerous additional embodiments. Moreover, while various materials, sizes, shapes, constructions, and positions, etc., have been described for the disclosed embodiments, other materials, sizes, shapes, constructions, and positions, besides those disclosed, may be utilized without departing from the scope of the claimed invention.

[0056] Those skilled in the art will recognize that the subject matter of this invention may include fewer features than those shown in any of the individual embodiments described above. The embodiments described herein are not intended to be an exhaustive representation of all possible combinations of features of the subject matter of this invention. Therefore, the embodiments are not mutually exclusive combinations of features; rather, as will be understood by those skilled in the art, various embodiments may include combinations of different individual features selected from different individual embodiments. Furthermore, elements described with respect to one embodiment may be implemented in other embodiments, even if not described in such embodiments, unless otherwise stated.

[0057] While dependent claims may relate to specific combinations with one or more other claims in the claims, other embodiments may also include combinations of dependent claims with the subject matter of each other dependent claim, or combinations of one or more features with other dependent or independent claims. Such combinations are presented herein unless otherwise stated.

[0058] Any merging of the foregoing documents by reference is limited to the exclusion of subject matter contrary to the explicit disclosure herein. Any merging of the foregoing documents by reference is further limited to the exclusion of any claims included in the documents by reference. Any merging of the foregoing documents by reference is further limited to the exclusion of any definitions provided in the documents by reference unless expressly included herein.

[0059] For the purposes of interpreting the claims, it is clearly intended that the provisions of 35 USC §112(f) shall not be invoked unless the specific terms “means for…” or “steps for…” are recited in the claims.

Claims

1. A mechanical seal assembly suitable for use in a device surrounding a rotational shaft of a rotating apparatus, the mechanical seal assembly comprising: A first sealing ring, which is axially movable relative to the rotating shaft during operation; The second sealing ring is axially fixed relative to the rotating shaft during operation; An annular support member is provided, which is fixed to the housing of the rotating device and has a base portion and a detachable end portion, wherein an axially movable first sealing ring is close to the annular support member and is axially movable relative to the annular support member in response to the axial movement of the rotating shaft and the axially fixed second sealing ring, and wherein the axially movable first sealing ring has an axially movable sealing surface that is in contact with the axially fixed sealing surface of the axially fixed second sealing ring; A biasing mechanism that pushes an axially movable first sealing ring toward an axially fixed second sealing ring, thereby using a closing force to engage the axially movable sealing surface with the axially fixed sealing surface. as well as An annular flexible sealing membrane, the annular flexible sealing membrane comprising: An external portion, which can be disposed between the first sealing ring, which is capable of axial movement, and the biasing mechanism, and which is capable of axial movement relative to the rotating shaft; An internal portion, which is surrounded by the external portion and positioned between the base portion and the detachable end portion of the annular support member. The annular flexible sealing membrane includes a central hole formed in an inner portion and arranged around the axis of rotation, the inner portion extending radially outward from the central hole, and the outer portion extending radially outward from the inner portion, wherein the annular flexible sealing membrane has a generally dumbbell-shaped cross-section to include the outer portion and the inner portion surrounded by the outer portion; When the outer portion moves relative to the rotation axis, the base portion and the detachable end portion keep the inner portion fixed relative to the annular support.

2. The mechanical seal assembly according to claim 1, wherein, The base portion has an upper surface in which a recess is formed, the recess being positioned close to the outer portion of the annular flexible sealing membrane.

3. The mechanical seal assembly according to claim 2, wherein, The detachable end portion has an upper surface in which a recess is formed, the recess being positioned close to the outer portion of the annular flexible sealing film.

4. The mechanical seal assembly according to claim 3 further includes an anti-compression ring disposed within a groove of the axially movable first sealing ring.

5. The mechanical seal assembly according to claim 1, wherein, The outer portion has a thicker cross-section than the inner portion.

6. The mechanical seal assembly according to claim 1, wherein, The biasing mechanism includes an axially movable annular retainer near the outer portion and a plurality of radially spaced spring members disposed between the annular support and the annular retainer.

7. The mechanical seal assembly of claim 1, further comprising a rotating sleeve operably coupled to the rotating shaft for rotation therewith, wherein an axially fixed second sealing ring is operably coupled to the sleeve.

8. The mechanical seal assembly according to claim 7, wherein, The axially fixed second sealing ring is operably connected to the sleeve by a plurality of pins.

9. The mechanical seal assembly according to claim 1, wherein, The sealing membrane comprises a flexible elastomer.

10. The mechanical seal assembly according to claim 9, further comprising an anti-compression ring disposed within a groove of the axially movable first sealing ring.

11. The mechanical seal assembly according to claim 10, wherein, The anti-compression ring comprises a material of the flexible elastomer with a hardness greater than that of the sealing membrane.

12. The mechanical seal assembly according to claim 1, further comprising: A sealing plate adapted to be connected to the housing; The carrier is connected to the sealing plate.

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