ES2605456T3 - Mechanical seal resistant to mismatches - Google Patents

Abstract

A mechanical seal (10) for sealing a fluid in a space between an equipment housing (14) and a rotating equipment shaft (11), including: a shaft sleeve (19) mountable on the rotating shaft (11) of so that it can rotate in unison with the axis (11) around an axis axis (12), said axis sleeve (19) having a respective support surface (35) oriented transverse to the axis axis (12) so that look axially; a sealing gasket (23) mountable in the equipment housing (14) so as to define a radially defined annular chamber (43) between said shaft sleeve (19) and said gland (23), said gland (23) having a respective support surface oriented transverse to the axis axis (12) in axially spaced opposite relationship with said support surface of said axis sleeve (19); a first sealing ring (31, 51) mounted on said shaft sleeve (19) for rotation therewith and having a flat front sealing surface (33, 53) and a rear ring surface respectively facing said support surface of said shaft sleeve (19); a second sealing ring (32, 52) non-rotatably mounted on said stuffing box (23) that is substantially coaxial with said first sealing ring (31, 51) and has a rear ring surface respectively facing said support surface of said cable gland (23), said second sealing ring (32, 52) having a flat front sealing surface ((34, 54) disposed in front sealing relationship with said front sealing surface (33, 53) of said first sealing ring (31, 51) to separate first and second regions of said annular chamber (43) during relative rotation of said first (31, 51) and second (32, 52) sealing rings during rotation of the shaft (11), said first seal rings (31, 51) and second (32, 52) being formed of disparate sealing ring materials having disparate thermal conductivities, characterized in that a thermal conducting ring of said seal rings first (31, 51) and it gundo (32, 52) is a thermal conductor and has a thermal conductivity greater than the other of said first (31, 51) and second (32, 52) sealing rings, said thermally conductive sealing ring having a thermally thin intermediate sheet conductive (90, 91) mounted between said heat conductive sealing ring (31, 51) and its respective support surface, said respective support surface being defined by a thermal conductive material where a heat dissipation flow path from said ring of thermal conductive seal (31, 51), through said intermediate sheet (90, 91), and to said respective support surface is thermal conductor such that the heat accumulated between said front sealing surfaces (33, 34, 53, 54) during the rotation of the shaft is taken from said front sealing surfaces (33, 34, 53, 54), through said thermal conductive sealing ring (31, 51) and said intermediate sheet (90, 91) to said s surface respective contribution and dissipates from it.

Description

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DESCRIPTION

Mechanical seal resistant to mismatches Cross reference to related request

This application claims the benefit of the US Provisional Application serial number 61/003 831, filed on November 20, 2007, which is incorporated herein by reference in its entirety.

Field of the Invention

The invention relates to a mechanical seal arrangement that is configured so as to dissipate excessive heat from the mechanical seal faces resulting from disturbance conditions such as poor lubrication conditions that may occur during dry running of the seal mechanics.

Background of the invention

Mechanical seals generate significant heat loads at an interface between a flat rotating joint face and an opposite flat stationary joint face. Said heat loads are due to contact friction between the faces and the viscous stress of the lubricating fluid between the faces. The extraction of this heat is usually carried out by convection with gaseous or liquid fluids on the surfaces of the rotating and stationary joint faces, and conduction in positions where the face comes into contact with metal parts, see USA-5 544 896.

The temperature on the sealing faces faces directly with the heat generation, and inversely with the convection and conduction coefficients. In fluids that act as poor lubricants and as poor convective means such as air or other gases, heat conduction to the metal components of the seal and the sealed equipment is critical to determine the temperature of the seal face.

In typical mechanical seals, the conduction coefficient is poor between a seal face and a metal part due to the rigid nature of both the mechanical seal face and the metal part, resulting in air intervals between pieces. Under dry operating conditions, continuous contact between the sealing faces can result in excessively high joint face temperatures where excessive temperature can quickly lead to failure of the seal, for example by damage to the sealing rings. carbon seal and damage of the toric joints, in particular those that are in contact with the other ring that can be made of silicon carbide.

With respect to such problems, in particular in dry operating conditions, some mechanical seals can perform heat extraction from the faces, where, for example, the surface area of the seals faces in contact with the process fluid can Increase heat convection. This works well in normal operating conditions where convection is the primary mode of heat extraction; however, this does not solve the problem of high temperatures of the seal face associated with dry operating conditions. In addition, a seal face surface in direct contact with a metal surface tends to conduct heat from the sealing ring to the metal surface. This improves the conductivity, but only to the extent that the flatness of the metal and surface of the gasket face in the contact interface is controlled. The brunido can improve the superficial contact in the interface although this has the counterpart of a significant additional expense.

Therefore, an object of the invention is to overcome difficulties of heat dissipation resulting from dry operation and other mismatch conditions.

In view of the above, the invention relates to a method for improving heat extraction from mechanical seal faces that results in a significant increase in the ability of the seal to tolerate poor lubrication conditions such as dry running. where heat loads increase and convection cooling is poor.

The mechanical seal of the invention employs the following features: (1) A thin flat sheet of flexible thermal conductor graphite material placed between one of the mechanical seal faces and a metal surface such as a metal surface defined by a shaft sleeve or stuffing box that serves as a sealing ring holder. (2) The graphite sheet is located axially between the mechanical seal face plus thermally conductive and the metal face support part. The sealing face conductive material is preferably a ceramic or ceramic material, such as silicon carbide, tungsten carbide, silicon nitride, aluminum oxide, or a metal material such as stainless steel. (3) Fluid pressure and elastic forces are used to create a compression load between the seal face, the graphite sheet and the metal part to maximize continuous contact between the opposite faces of these parts and the opposite sides of the graphite sheet (4) The graphite sheet preferably has a thickness of 0.005 inches to 0.030 inches.

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More specifically, the invention incorporates a thin sheet of sheet graphite material that is sandwiched between a gasket face material of silicon carbide, tungsten carbide, silicon nitride or aluminum oxide and a metal seal gasket component such as the sleeve or stuffing box. The sheet is axially housed or interposed between the surface of the seal face, which is located opposite the primary sealing interface defined between opposite faces of the seal, and the surface of a rotating or stationary metal component such as a sleeve, stuffing box or rotating face support.

The sheet material is used to improve the heat conduction from the seal face to the metal component, thereby reducing the temperature of the seal face and improving the sealing performance, especially in conditions of poor lubrication such as dry running.

In dry running tests performed on a prototype mechanical seal design using a conventional direct metal conduit path from the mechanical seal face to a metal seal ring support, the temperature of the seal face reached at less than 10 minutes of dry running excessive temperatures high enough to damage the seals and cause seal failure. This temperature degrades the materials and elastomers of the sealing gasket face in contact with the sealing gasket faces, quickly resulting in sealing gasket failure. When the novel seal was checked with the graphite sheet between the seal face and the metal sleeve, the temperatures of the seal face were substantially lower and did not reach the level that caused seal failure. The ability of the sealed seals to operate without seal failure is several times longer and in some cases it may be able to avoid the tight seal failure caused by elevated temperatures for up to one hour of dry operation.

The sheet graphite material includes a flexible, industrial grade, flat sheet graphite material available in the market, and has been shown to be effective in thicknesses from 0.005 inches to 0.030 inches in tests. The significant characteristics of the sheet that allow the conduction are: (1) the ability of the material to adapt to the surface variations of both the seal face and the metal part, increasing the contact between the parts and therefore the conductivity ; (2) high thermal conductivity in the transverse plane of the sheet, which allows better conduction in any areas where the sheet does not fully adapt; and (3) high thermal conductivity in the axial plane of the sheet, which allows heat flow.

The general use of a seal between a seal face and a metal component takes place in some seals. However, in these applications, the seal material is not thermal conductor and only serves as a means to prevent damage or distortion of the seal faces.

In addition, some commercially available gaskets use a wavy graphite gasket between a carbon graphite gasket face and a metal component. In this type of application, the use of such a seal is as a flexible seat and drive mechanism for the face. In this example, the seal is a graphite thermal conductive material, but the carbon graphite seal face material is not a thermal conductor and therefore does not provide the operational benefit of heat extraction from the defined interface between two opposite faces of tight seal. Therefore, the carbon graphite seal prevents heat transfer from the other sealing ring.

The improved mechanical seal of the invention thus improves the heat conduction away from the seal faces by using the flat graphite sheet where this feature can be incorporated into the development of new mechanical seal products aimed at industrial applications. Chemists and generals worldwide. With respect to this product alone, the increase in yield produced by the sheet is significant because it improves the ability of the seal to survive and recover when it is subjected to non-designed operating conditions that typically produce seal failure in the existing seal. This improved heat transfer capacity results in greater reliability and overall durability of the product of the seals.

In addition to new products, the graphite sheet can also be incorporated into existing products and other new developments to improve performance of existing seal products.

Other objects and purposes of the invention and its variations will be apparent after reading the following specification and inspecting the accompanying drawings.

Brief description of the drawings

Figure 1 is a cross-sectional view of a mechanical seal assembly.

Figure 2 is a perspective view of an axle sleeve and a sealing ring with a heat transfer sheet material positioned such that it is sandwiched between the sealing ring and the shaft sleeve.

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Figure 3 is an enlarged perspective view of the assembly of Figure 2.

Figure 4 is an enlarged view of a pair of sealing rings and the shaft sleeve.

Figure 5 is an enlarged cross-sectional view of a sealing ring supported by the shaft sleeve in a driving pin position.

Figure 6 is a cross-sectional view of the sealing ring and shaft sleeve in a circumferentially offset position of the drive pin.

Certain terminology will be used in the following description for reasons of convenience and reference only, and will not be limiting. For example, the terms "up", "down", "right" and "left" will refer to directions in the drawings referred to. The terms "inward" and "outward" shall refer to directions of approach and distance, respectively, of the geometric center of the arrangement and its designated parts. Said terminology shall include the specifically mentioned terms, their derivatives, and words of similar meaning.

Detailed description

With reference to FIG. 1, a mechanical seal arrangement 10 according to the present invention is illustrated in a configuration of a double impeller contact seal, where the seal arrangement 10 is disposed in concentric relation to an elongated shaft 11 which can rotate around its axis 12 and driven by a motor (not illustrated) at one end and moves a component equipment such as an impeller at the opposite end. The double seal arrangement cooperates with a chamber or stuffing box 16 associated with a housing 14 of the equipment from which the shaft 11 protrudes, such as a pump intended for use in chemical and general industrial applications.

The mechanical seal arrangement 10 includes an inner seal assembly 17 that is positioned more adjacent to the product being handled, such as the pumping chamber, and an outer seal assembly 18 that is disposed out of the inner seal assembly 17 , but axially in series with it. These sealing assemblies 17 and 18, in the illustrated embodiment, are concentrically mounted on an elongate shaft sleeve 19 that concentrically surrounds and is not rotatably fixed relative to the axis 11. A fixing ring 21 is mounted on the sleeve 19 adjacent to its outer end, and is provided with a plurality of fixing screws 22 for fixing to the shaft.

The seal assembly 10 partially protrudes from the chamber 16, the outer portion of the seal arrangement 10 being disposed within and surrounded by a gland or housing part 23 which, in the illustrated embodiment, is defined by a pair of gland rings 24 and 25 that axially and hermetically support each other. The gland rings 24 and 25 are axially fixed together and fixedly and sealed in relation to the housing 14. The inner gland ring 25 has an annular hub portion 26 that telescopes at the outer end of the chamber 16 so that It is placed in surrounding relationship with the inner seal assembly 17. A seal 27 cooperates between the housing 14 and the gland ring 25 to create a sealed relationship between them.

With reference now to the inner seal assembly 17, it includes a rotary seal ring (a rotor) 31 and a stationary seal ring (a stator) 32 which substantially surround the axis 11 and define respectively flat annular seal faces 33 and 34 which are maintained in relative rotary sliding contact of support with one another creating a seal between the regions arranged radially in and out thereof.

A cup-shaped ring 35 surrounds on the outside and extends axially along the shaft sleeve 19, and is adapted to receive a sealing toric seal 36. The ring 35 engages in a sealed manner with a portion of annular hub projecting toward back 37 of the rotor 31 through the intermediate elastomeric sealing ring 36. One or more drive pins 38 are fixed to the ring 35 in angularly spaced relationship around, and axially protrude from it to recesses or grooves 39 formed in the rotor 31 so that connect the rotor 31 to the ring 35 non-rotationally where the rotor 31 rotates to the umsono with the axis 19.

As for the stator 32, it has a staggered outer cylindrical wall 42 that is axially slidably housed within a similar inner wall defined by a staggered hole 41 formed in the annular hub portion 26 of the gland ring 25. Such opposite staggered walls they define an annular chamber 43 in between in which an elastomeric sealing ring 44 is housed to create a sealed relationship between the stator 32 and the gland ring 25.

The annular hub portion 26 has a spring support 45 having one or more pins fixed thereon at angularly spaced intervals such as pins 38, which conventionally protrude axially to recesses that open axially into the stator 32 like recesses 39 of so that they do not rotate the

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stator 32 to the gland ring 25. More recesses 48 have been axially formed in the spring support 45 in circumferentially spaced relationship, and these recesses 48 accommodate springs 49 which react between the spring support 45 and the gland ring 25 so that always elastically push the stator 32 axially towards the rotor 31 to maintain contact between the seal faces 33 and 34, and, in turn, axially push the rotor 31 to the ring 35. Although the springs 49 are used in the construction of sealed illustrated, it is also known to use a bellows that is used instead of springs 49 and serves to define the thrust function.

The outer seal assembly 18 is of similar construction because it includes a rotary seal ring (a rotor) 51 and a stationary seal ring (a stator) 52 which respectively have flat annular seal faces 53 and 54 held in relatively sliding contact. Rotating with each other to maintain a tight seal between regions arranged radially in and out. The rotor 51 externally surrounds and engages in a sealed manner in relation to the shaft sleeve 19 by a ring 56 which surrounds and engages in a sealed manner with the rotor 51 through an elastomeric sealing ring 55 disposed therebetween.

The ring 56 is fixedly attached to the shaft sleeve 19 and has one or more circumferentially spaced actuation pins 57 fixed thereto as the pins 38. In turn, these pins 57 protrude to recesses 58 formed in the rotor 51 as the recesses 39 for non-rotating coupling the rotor 51 to the axis 11.

Stator 52 is stationary positioned within an annular recess 62 defined within the gland ring 24, an elastomeric sealing ring 63 acting in between to create a sealed relationship. A plurality of pins 65 (such as pins 38) are fixed to the gland ring 24 and protrude axially from it to recesses 66 (such as recesses 39) formed on the rear face of the stator 52 to non-rotatably fix the stator 52 with relation to the gland ring 24.

The cable gland 23 has an opening 71 formed radially therethrough for communication with an annular chamber 72 which is defined within the gland in relation to at least a part of the double seal arrangement 10. This annular chamber 72, which is the Intermediate gas chamber as explained below, surrounds the outer seal assembly 18 and also includes an annular chamber portion 73 that is associated within the stator 32 with the inner seal assembly 17.

To supply a pressurized gas such as air or nitrogen to chamber 72, the inlet opening 71 is normally coupled to a supply line in a conventional manner, whose inlet is coupled to a conventional source of a pressurized inert buffer gas. In operation, the pressurized inert gas is supplied through the inlet 71 to the annular chamber 72. The buffer gas also occupies the annular secondary chamber 73 and can be a gas or liquid that can be pressurized or depressurized.

During the operation of the seal arrangement, the rotors 31 and 51 rotate at the umsono with the axis 11, where their respective seal faces 33 and 53 contact the opposite seal faces 34 and 54 to define each respectively an interface sealing that resists the migration of fluid through the sealing interface. Primarily, the inner sealing ring assembly 17 makes a tight seal against the escape of process fluid from the stuffing box chamber 16 to the buffer fluid chamber 73.

Due to the contact between the opposite faces of the seal, the sealing rings are conventionally made of different materials. In the illustrated embodiment, the two stators 32 and 52 are formed of carbon or other comparable sealing ring material. However, the rotors 31 and 51 are usually made of a harder disparate material and preferably silicon carbide, although other ceramic or ceramic materials such as tungsten carbide, silicon nitride, aluminum oxide or a metallic material can be used. such as stainless steel. The shaft sleeve 19 and the gland rings 24 and 25 in which the sealing rings 31, 32, 51, 52 are seated, are formed of type 316 stainless steel or other comparable metal.

Generally, mechanical seals generate significant heat loads at the sealing interface, such as between the flat rotating joint face 33 or 53 and the opposite flat stationary joint face 34 and 54. Such heat loads result from the high-speed rotation of the axis 11 which performs a relative movement between the components, where such heat generation is due specifically to the contact friction between the faces 33/34 or 53/54 and the viscous stress of the lubricating fluid that migrates radially between the faces 33/34 or 53/54. The temperature on the sealing faces 33/34 or 53/54 varies directly with the heat generation, and inversely with the convection and conduction coefficients that help dissipate heat through the seal components, the internal chambers and the fluid they contain. However, in fluids that act as poor lubricants and as poor convective media such as air, nitrogen or other gases, heat accumulates to a greater extent.

In addition, heat generation greatly increases during mismatch conditions such as dry operating conditions where the process fluid is lost from the stuffing box 16 resulting in a loss of lubricating process fluid between the opposite joint faces. tight 33/34 or 53/54 and a substantially large heat generation. Under dry running conditions, continuous contact between the seal faces can lead to excessively high temperatures of the seal face, where the

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Excessive temperature can quickly lead to seal failure.

To greatly improve the ability of the seal assembly 10 to resist the heat accumulated by the cooperation of the opposing faces of seal 33/34 or 53/54, the seal 10 of the invention also includes transfer sheets of heat 90 and 91 between the rotors 31 and 51 and the opposite surfaces of the rings 35 or 56 on which they seat. Since the rotors or sealing rings 31 and 51 seated in rings 35 and 56 are structurally and functionally similar, the explanation of Figures 2-6 refers to rotor 31 and associated ring 35, the following explanation also applies to the sealing ring 51 and the associated ring 56.

With reference to Figures 2-6, the rotor 31 has the hub portion 37 which defines a rear hoop face 92 that faces in an axial direction opposite to the seal face 33. The hoop face 92 extends circumferentially and it is continuously smooth except in the positions in which the drive pin grooves 39 have been formed. As such, the rear ring face 92 is formed by arcuate face segments 93 arranged on opposite sides of each slot 39.

As for the ring 35, this ring 35 defines an axially open cavity 95 (Figures 5 and 6) that receives the rotor hub portion 37. The cavity 94 includes a ring face 96 facing the rear ring face 92 of so that they are substantially parallel to each other in frontal relationship. The ring face 96 also includes holes 97 that receive the drive pins 38 as seen in Figure 5, pins 38 that protrude into the sealing ring grooves 39.

In addition, the heat transfer sheet 90 is provided as seen in Figures 2, 3 and 6, sheet 90 having a substantially annular planar shape that extends circumferentially. The sheet 90 optionally includes an interval 98 for each of the drive pins 38 and the grooves 39. Where multiple grooves 39 and pins 38 are provided, the blade 90 practically includes a plurality of separate arcuate leaf sections 100 that cover and delineate the arcuate face segments 92 of the rotor 31. The blade 90 is thin in the axial direction and wide in the radial transverse direction and defines opposite blade faces 101 and 102 that are interspersed in compression between and contact the ring face respectively sealing 93 and the ring face 96 as seen in Figure 6. Preferably, the graphite sheet has a thickness of 0.005 inches to 0.030 inches. As such, there is continuous surface contact over the entire surface areas of the sheet faces 101, 102, the sealing ring face 93 and the ring face 96.

During installation, the sheet 90 is preferably glued or adhered to the sealing ring face 93, where the sheet 90 is preferably formed as a continuous annular ring of a piece, and once attached in position, the sections of the sheet 90 lining or bridging the annular grooves 39 are manually cut to define the intervals 98. The adhesive is thin enough and of a suitable composition to allow efficient heat transfer from the rotor 31 to the sheet 90. The sheet 90 is sufficiently thin so that it is flexible and therefore adapts essentially to the flatness of the ring face 93 continuously in its surface area.

When the rotor 31 sits on the ring 35, the blade 90 also has its surface 90 hermetically pushed against the opposite ring face 96 so that it essentially adapts to the flatness of the ring face 96 continuously over its surface area and allow heat transfer from sheet 90 to ring 35.

In view of the foregoing, the invention relates to a method for improving heat extraction from mechanical seal faces 33/34 and 53/54 which results in a significant increase in the ability of the seal 10 to tolerate poor lubrication conditions, such as dry running. Where heat loads increase and convection cooling is poor.

In this regard, sheets 90 and 91 are located in the seal 10 next to a thermally conductive sealing ring, namely the rotors, 31 or 51 of each opposite pair of sealing rings. The other sealing rings, namely stators 32 and 52, are carbon and have a significantly lower thermal conductivity compared to rotors 31 and 51. As previously indicated, rings 35 and 56 are formed of a metal that It is thermal conductor and is not insulating. By placing the intermediate heat transfer sheets 90 and 91 interspersed between the thermal conductive sealing rings 31 and 51 and the respective thermal conductive rings 35 and 56, the heat accumulated on the sealing gasket faces moves away from them through paths of heat dissipation flow extending from the sealing gasket faces, to the sheets 90 and 91 and then through the sheets 90 and 91 to the rings 35 and 36 that are better able to dissipate the heat. The sheets 90 and 91, in combination with the associated sealing rings and the supporting surfaces, define flow paths having a total conductivity corresponding to the individual thermal conductivities of the sheets, the sealing rings and the supporting surfaces as well as the general conductivity defined at the interfaces between these components. However, in the other sealing ring, the total thermal conductivity is substantially lower due to the material of the sealing ring and any structures existing between the sealing ring and its support surface such as the springs located above and any spaces associated with them. .

Therefore, the mechanical seal 10 of the invention employs the following features: (1) A thin flat sheet of flexible thermal conductive graphite material positioned between one of the sealing ring hoop faces

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mechanics, such as the face 93, and a metal surface, such as the metal surface 96 defined by the ring 35 of the shaft sleeve 19. It is also possible that the sealing rings may be inverted such that the rings of sealed thermal conductors are stators 32 and 52 that are supported in the gland rings 24, 25 so that the gland 23 serves as the sealing ring support. In this case, the sheets 90 and 91 are sandwiched between the sealing rings 32 and 52 and the cable gland 23. (2) The graphite sheet 90, 91 is located axially between the mechanical seal face plus thermal conductive 31 and 51 and the metal face support part. The sealing face conductive material is preferably a ceramic or ceramic material such as silicon carbide, tungsten carbide, silicon nitride, aluminum oxide or a metal material, such as stainless steel. (3) Fluid pressure and elastic forces are used to create a compression load between the seal face as face 93, the flat graphite intermediate sheet 90 and the metal part as ring 35 to maximize continuous contact between the opposite sides of these parts and opposite sides of the graphite sheet. (4) The graphite sheet has a thickness of 0.005 inches to 0.030 inches so that the sheet can be compressed and adapted to both sides between which it is sandwiched and can easily transfer heat through the sheet material.

More specifically, the invention is based on a thin sheet of non-reinforced graphite sheet material that is sandwiched between a sealing face material of silicon carbide, tungsten carbide, silicon nitride, or aluminum oxide and a metal component of the seal such as the sleeve or the gland. The sheet is axially housed or interposed between the surface of the seal face, which is located opposite the primary sealing interface defined between opposite faces of the seal, and the surface of a rotating or stationary metal component such as a sleeve, stuffing box, or rotating face support.

The sheet material is used to improve the heat conduction from the seal face to the metal component, thereby reducing the temperature of the seal face and improving the sealing performance, especially in conditions of poor lubrication such as dry running.

In dry running tests performed on a prototype mechanical seal design using a conventional direct metal conduit path from the mechanical seal face to a metal seal ring support, the temperature of the seal face reached at less than 10 minutes of dry running excessive levels that were sufficient to damage the sealing ring components. This temperature will degrade the gasket face materials and the elastomers in contact with the watertight gasket faces, quickly leading to seal gasket failure. When the invention was tested with the graphite sheet disposed between the seal face and the metal sleeve, the temperatures of the seal face did not reach damage levels in one hour of dry operation or at least several times longer that the seals not built according to the invention.

The sheet graphite material includes a flexible, industrial grade, flat sheet graphite material available in the market, and has been shown to be effective in thicknesses from 0.005 inches to 0.030 inches in tests. The key features of the sheet that allow the conduction are: (1) the ability of the material to adapt to the surface variations of both the seal face and the metal part, increasing the contact between the parts and therefore the conductivity ; (2) high thermal conductivity in the transverse plane of the sheet, which allows better conduction in any areas where the sheet does not fully adapt; and (3) high thermal conductivity in the axial plane of the sheet, which allows heat flow.

Preferably, the thermal conductivity of the components is as follows: (1) the intermediate sheet material between the sleeve or gland and the thermally conductive seal face has a general conductivity of between 5 and 250 W / M * K (2.9 at 144.5 Btu / h * foot * F); (2) the intermediate sheet material has a higher conductivity along the plane of the sheet of 100 to 250 W / M * K (57.8 to 144.5 Btu / h * foot * F) and may have a conductivity normal inferior to the sheet plane being still thermal conductor; and (3) The sealing face material is highly thermally conductive, with a conductivity greater than 30 W / M * K (17.4 Btu / h * foot * F).

These thermal conductivities and the structural cooperation between the thermal conductive sealing ring, the intermediate heat transfer sheet and the sealing ring support thus define a flow path away from the heat-generating seal faces and towards the sealing ring holder used to dissipate heat accumulation. So, generally, the sealing rings are formed of disparate sealing ring materials that have disparate thermal conductivities where a thermal conducting ring of said sealing rings is thermal conducting and has a thermal conductivity larger than the other of the rings sealing. The thermal conductive sealing ring has a thermally conductive thin intermediate sheet mounted between the thermal conductive sealing ring and its respective support surface, in turn defining the respective support surface by a thermal conductive material. As such, a heat dissipation flow path extends from the thermally conductive sealing ring, through the intermediate sheet, and to the respective supporting surface that is thermally conductive where the heat accumulated between the sealing ring surfaces during The rotation of the shaft is removed from the sealing ring surfaces, through the thermal conductive sealing ring and the intermediate sheet to the respective support surface and dissipates.

It is possible that the sealing rings can be formed even of disparate materials or, alternatively, can

have thermal conductivities that are different, but still similar, and in that case, one of the sealing rings is structured or has an intermediate material between the sealing ring and its support surface that interrupts the heat flow path between this sealing ring and its support structure such as a gland or sleeve. For example, a spring-loaded sealing ring has intervals between the sealing ring and the support 5 defined by the stuffing box or the shaft sleeve. Therefore, in such an example, although the sealing rings may have the same or similar values of thermal conductivity, the total thermal conductivity of the heat flow paths from the two sealing rings may differ substantially or be triggered in such a manner. that the thermal conductive sealing ring has a thermal conductive flow path due to the intermediate sheet in contact with it, and the other sealing ring has a heat flow path that is in fact insulating or has a low thermal conductivity of such that the heat moves away from the sealing ring faces by the sealing ring and its intermediate sheet.

Although a specific preferred embodiment of the invention has been described in detail for illustrative purposes, it will be recognized that variations or modifications of the described apparatus, including the redisposition of parts, fall within the scope of the present invention. For example, it will be understood that although a double seal configuration is shown, a unique seal configuration can also be provided.

Claims (14)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 1. A mechanical seal (10) for sealing a fluid in a space between an equipment housing (14) and a rotating equipment shaft (11), including: a shaft sleeve (19) mountable on the rotary shaft (11) so that it can rotate the shaft with the shaft (11) around an axis shaft (12), said shaft sleeve (19) having a supporting surface respective (35) oriented transverse to the axis axis (12) so that it looks axially; a sealing gasket (23) mountable in the equipment housing (14) so as to define an annular chamber (43) defined radially between said shaft sleeve (19) and said gland (23), said gland (23) having a respective support surface oriented transverse to the axis axis (12) in axially spaced opposite relationship with said support surface of said axis sleeve (19); a first sealing ring (31, 51) mounted on said shaft sleeve (19) for rotation with it and having a flat front sealing surface (33, 53) and a rear ring surface respectively facing said support surface of said shaft sleeve (19); a second sealing ring (32, 52) non-rotatably mounted on said stuffing box (23) that is substantially coaxial with said first sealing ring (31, 51) and has a rear ring surface respectively facing said support surface of said gland (23), said second sealing ring (32, 52) having a flat front sealing surface ((34, 54) disposed in relation to frontal sealing with said front sealing surface (33, 53) of said first sealing ring (31, 51) to separate sealed first and second regions of said annular chamber (43) during the relative rotation of said first (31, 51) and second (32, 52) seal rings during rotation of the shaft (11); said first (31, 51) and second (32, 52) seal rings being formed from disparate sealing ring materials having disparate thermal conductivities, characterized in that a thermal conducting ring of said first seal rings (31, 51) and second (32, 52) is a thermal conductor and has a thermal conductivity greater than the other of said first (31, 51) and second (32, 52) sealing rings, said thermal conductor sealing ring having a thin intermediate sheet thermally conductive (90, 91) mounted between said thermal conductive sealing ring (31, 51) and its respective support surface, said respective support surface being defined by a thermal conductive material where a heat dissipation flow path from said ring of thermal conductor sealing (31, 51), through said intermediate sheet (90, 91), and to said respective support surface is thermal conductor such that the heat accumulated between said sealing surfaces d front (33, 34, 53, 54) during rotation of the shaft is carried from said front sealing surfaces (33, 34, 53, 54), through said thermal conductive sealing ring (31, 51) and said sheet intermediate (90, 91) to said respective support surface and dissipates from it. 2. The mechanical seal according to claim 1, wherein said heat flow path has a thermal conductivity larger than a thermal conductivity between said other sealing ring (32, 52) and its respective support surface. 3. The mechanical seal according to any of the preceding claims, wherein said other sealing ring (32, 52) has been formed of a carbon material. The mechanical seal according to any of the preceding claims, wherein said intermediate sheet (90, 91) has been formed of thermally conductive graphite and is compressed in substantially continuous frontal contact between said rear hoop face and said respective support surface. 5. The mechanical seal according to any of the preceding claims, further including a thrust means for axially pushing one of said first (31, 51) and second (32, 52) seal rings towards the other of said sealing rings first and second where said intermediate sheet (90, 91) is arranged in compression between said rear ring face and said respective support surface. 6. The mechanical seal according to any of the preceding claims, wherein said intermediate sheet (90, 91) has been formed of thermal conductor graphite having a general thermal conductivity of between 5 and 250 W / M * K. 7. The mechanical seal according to any of the preceding claims, wherein said sealing face material is highly thermally conductive with a conductivity greater than 30 W / M * K. 8. The mechanical seal according to any of the preceding claims, wherein said respective support surface has been formed of a thermal conductive metal. 9. The mechanical seal according to any of the preceding claims, wherein the thermal conductivity 5 10 fifteen twenty 25 through said other sealing ring (32, 52) and its respective support surface is lower than the thermal conductivity through said heat dissipation flow path. 10. The mechanical seal according to any of the preceding claims, wherein said thermal conductivity of said other sealing ring is inferior to said thermal conductivity of said thermal conductive sealing ring. 11. The mechanical seal according to any of the preceding claims, wherein said thermal conductive sealing ring is said first sealing ring (31, 51). 12. The mechanical seal according to any of the preceding claims, wherein said thermal conductive sealing ring is said second sealing ring (32, 52). 13. The mechanical seal according to any of the preceding claims, wherein said intermediate sheet (90, 91) has been formed of thermal conductive graphite having a general thermal conductivity of between 5 and 250 W / M * K with a higher conductivity along a transverse plane of the sheet of 10.0 to 250 W / M * K and a conductivity lower than normal to the sheet plane while still being thermally conductive, and said sealing face material is also highly thermally conductive with a conductivity greater than 30 W / M * K. 14. The mechanical seal according to any of the preceding claims, wherein said rear face of said thermally conductive sealing ring has drive grooves (39) that separate circumferential segments from said rear face, covering said intermediate sheet (90, 91) said circumferential segments and having intervals in the area of said grooves (39) so that drive pins (38) can extend axially from said respective support surface to said drive grooves.