WO2013155150A1

WO2013155150A1 - Cone crusher dust seal

Info

Publication number: WO2013155150A1
Application number: PCT/US2013/035919
Authority: WO
Inventors: Laurence James MCMAHON
Original assignee: Nawa Engineers And Consultants Pvt. Ltd
Priority date: 2012-04-10
Filing date: 2013-04-10
Publication date: 2013-10-17

Abstract

The present inventive dust seal assembly substantially improves the prevention of dust entry into a flat head cone crusher or a steep head cone crusher and substantially improves its ease of use and durability. The present inventive dust seal assembly includes non-fixed or floating labyrinth seals, does not require lubrication, and is effective for use with flat head cone crushers and steep head cone crushers using roller bearings. The dust seal assembly may comprise multiple non-fixed or floating horizontal labyrinth seals and labyrinth seal retainers, an attachment assembly to secure the multiple horizontal labyrinth seals and labyrinth seal retainers to either a cone head or an inner bonnet, a cone crusher inner bonnet adapted to interface with the multiple labyrinth seals and labyrinth seal retainers and, optionally, injection of pressurized air within the dust seal assembly itself.

Description

TITLE OF THE INVENTION

Cone Crusher Dust Seal

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of dust seals for use with flat head and steep head cone crushers. Specifically, the present invention comprises a cone crusher horizontal multiple labyrinth dust seal system that includes non- fixed or floating labyrinth seals and operates without external lubrication. The present invention can be effectively used with flat head and steep head cone crushers having roller bearings. The dust seal of the present invention is highly durable and its construction provides ready access to the dust seal components to ease any dust seal maintenance.

2. Description of Related Art

Effective dust seals for cone crushers have proved extremely difficult to achieve. The internal working parts of cone crushers (bearings, gears, shafts, oil pumps, lubricating oil, etc.) must be protected from both rock dust generated during crushing and other contaminants, otherwise the cone crushers become too costly to maintain. Regardless of how good a cone crusher may be, if rock dust and other contaminants cannot be excluded from interfering with its internal working parts, the cone crusher is not viable for practical efficient and economic use.

Various efforts to improve upon dust seals used with cone crushers have included the rubbing seal (e.g., U.S. Patent No. 4,919,348 to Johnson et al), grease seal (e.g., U.S. Patent No. 3,771,735 to Decker et al), flexible seal (e.g., U.S. Patent No. 3,140,834 to Symons), and labyrinth seal (e.g., U.S. Patent No. 2,713,461 to Kjelgaard, U.S. Patent No. 3,473,743 to Winter, and U.S. Patent No. 4,084,756 to Coxhill) mechanisms. None of these efforts, however, have successfully eliminated the problem of dust entry. Further, each of these proffered dust seal designs has its own contingent design flaws and weaknesses that lead to dust entry, increased cone crusher maintenance cost, and reduced efficiency. For example, these dust seal designs are not sufficiently durable, require frequent maintenance and/or replacement of parts, involve the messy and problematic use of lubricating substances within the dust seal itself, etc. Accordingly, there is substantial room for improvement in the field of dust seals for use with cone crushers. Dust seal mechanisms used in steep head and flat head cone crushers also differ in that steep head cone crusher seals must account for the vertical adjustment of the cone crusher shaft over the course of use (for setting adjustments, tramp relief, other crushing overload relief, etc.). Also, the seals used with steep head cone crushers and with flat head cone crushers typically differ in that they require greater clearance between their component parts to accommodate vertical movement. By contrast, because the component parts of flat head cone crusher seals do not need to move up and down with the cone crusher shaft, their component parts permit a closer and more compact configuration since the radial and axial clearances can be much closer.

Regardless of whether a cone crusher is a steep head or a flat head, it is particularly notable that dust entry prevention into cone crushers using roller bearings is of paramount importance. This is because cone crushers using roller bearings require better sealing than do crushers using plain bearings or bronze bushes. For example, while cone crushers using bronze bushes must still protect against dust entry, the deleterious effect of dust into the bronze bushes mechanism is not as damaging in the short term as it would be for a cone crusher using roller bearings. None of the dust seals conventionally available or otherwise disclosed in the prior art achieves satisfactory prevention of dust entry into cone crushers using roller bearings.

BRIEF SUMMARY OF THE INVENTION

The present invention addresses problems not resolved by conventional cone crusher dust seals. The present inventive dust seal assembly substantially improves the prevention of dust entry into the cone crusher by providing minimal air clearance between closely matched sealing assembly components, including non-fixed or floating labyrinth seals, by presenting a more arduous path to dust entry, by providing a lubrication-free environment that prevents the formation of deleterious lapping compounds comprising dust, and, optionally, by providing air pressure delivered directly within the dust seal assembly itself to further prevent dust entry. The present inventive dust seal assembly also has substantially improved durability due to its provision of closely matched sealing assembly components comprised of compatible low- friction materials designed to wear in to each other, including non- fixed or floating labyrinth seals, its exclusion of functional rubberized or flexible components, its provision of a lubrication-free environment that prevents the formation of lapping components, its improved ease of repair and maintenance, and, optionally, its provision of air pressure delivered directly within the dust seal assembly itself to further prevent dust entry.

The present inventive dust seal assembly can be used with either flat head or steep head cone crushers. The present inventive dust seal assembly includes non- fixed or floating labyrinth seals and does not require lubrication. In a particularly preferred embodiment, the present inventive dust seal assembly is used in a flat head or steep head cone crusher that uses roller bearings.

The dust seal assembly may comprise one or more of multiple components including, but not limited to, horizontal labyrinth seals and labyrinth seal retainers, a cone head sealing lip, a cone head oil baffle flange, an attachment assembly to secure one or more horizontal labyrinth seals and labyrinth seal retainers to a cone head, an inner bonnet, and/or an outer bonnet, a cone crusher inner bonnet adapted to interface with the multiple labyrinth seals and labyrinth seal retainers, and, optionally, an inner bonnet flange barrier.

In one embodiment for use with flat head cone crushers, the entire weight of the horizontal labyrinth seals and labyrinth seal retainers may be supported via attachment to the underside of the cone head, and these components do not carry the weight of the cone head itself. Here, the labyrinth seal retainers are fixedly attached to the cone head. The labyrinth seals are either located on top of or interposed between and supported by one or more of the labyrinth seal retainers, but the labyrinth seals are not fixedly attached to any component. The labyrinth seals and labyrinth seal retainers are well matched, provide little or no clearance between their contact surfaces, and present a novel, extremely difficult, and tortuous path to prevent the entry of dust.

In an alternative embodiment for use with either flat head cone crushers or steep head cone crushers, the entire weight of the horizontal labyrinth seals and labyrinth seal retainers may be supported via attachment to the inner bonnet. Here, at least one of the labyrinth seal retainers is fixedly attached to the inner bonnet. The labyrinth seals are either located on top of or interposed between and supported by one or more of the labyrinth seal retainers, but the labyrinth seals are not fixedly attached to any component. The labyrinth seals and labyrinth seal retainers are well matched, provide little or no clearance between their contact surfaces, and present a novel, extremely difficult, and tortuous path to prevent the entry of dust. The horizontal labyrinth seals and labyrinth seal retainers are generally spherical in shape and have convex and concave mating surfaces, respectively. The labyrinth seals and labyrinth seal retainers comprise substantially the same (differing no more than 0.127 mm on both mating radii), or exactly the same, radius. The labyrinth seals are loose, i.e., not fixedly attached axially to the cone crusher body or any other component. A small axial clearance, preferably, of about 1.27 mm to 1.52 mm, between one or more upper surfaces of the labyrinth seals and the lower surfaces of the labyrinth seal retainers improves mobility between the labyrinth seals and the labyrinth seal retainers. The contact area between the labyrinth seals and labyrinth seal retainers is large and, thus, the contact pressure between these components is reduced, which also reduces wear.

For example, in a preferred embodiment involving a double labyrinth dust seal used in a flat head cone crusher wherein the labyrinth seal retainers are fixedly attached to the cone crusher head, the calculated contact area at any one instant is about 2541.93 square centimeters. The weight of the upper labyrinth seal is about

62.82 kgs, the weight of the lower labyrinth seal is about 61.42 kgs and the collective weight of the upper and lower labyrinth seals is about 124.32 kgs. Accordingly, the dead weight of the multiple labyrinth seals approximates the total load on the labyrinth seal and labyrinth seal retainer contact surfaces, resulting in a light contact pressure of about 0.025 kgs per square centimeter for the upper labyrinth seal, and 0.024 kgs per square centimeter for the lower labyrinth seal. In addition to the small axial clearance between one or more upper surfaces of the labyrinth seals and the lower surfaces of the labyrinth seal retainers, there is a small axial clearance, preferably, of about 1.27 mm to 1.52 mm, between the upper surface of the top labyrinth seal and the bottom surface of the cone head sealing lip. Accordingly, in this preferred embodiment, none of the upper surfaces of the labyrinth seals contact other solid crusher components.

The materials used to produce the labyrinth seals and labyrinth seal retainers are selected to provide closely matched surfaces that resist distortion under heat, for example, temperatures greater than about 38 degrees Centigrade, that wear in to each other during operation of the dust seal assembly, and that, preferably, have surfaces that can be machined to within very close tolerances. Materials suitable for use with the present invention include, but are not limited to, labyrinth seal retainers comprising medium carbon steel hardened and tempered or spheroidal graphite cast iron, and labyrinth seals comprising bronze or spheroidal graphite cast iron or steel. Bronze or spheroidal graphite cast iron are preferred examples of two materials that are compatible with steel to provide low surface friction and the ability to wear in to the shape of the mating steel, without suffering surface damage.

In a preferred embodiment of the invention, the labyrinth seal retainers consist of medium carbon steel hardened and tempered. In another preferred embodiment of the invention, the labyrinth seals consist of one of bronze or spheroidal graphite cast iron.

In a preferred embodiment, the labyrinth seals are made from spheroidal graphite cast iron and the labyrinth seal retainers are made from a medium carbon cast steel that is hardened and tempered, for example, to 240/260 Brinell Hardness Number (BHN). A BHN within the range of 240/260 is moderately hard, and is sufficient to handle the type of contact wear involved in the present invention, without losing too much in ductility. The use of these preferred materials provides ideal low friction contact wear surfaces between the labyrinth seals and the labyrinth seal retainers. The metallurgical condition of these two materials is also very compatible for the light pressure surface contact rubbing action of the present invention.

Also in a preferred embodiment, the contact surfaces of the labyrinth seals and the labyrinth seal retainers are machined to a minimum surface finish of about 1.6 thousandths of a millimeter, i.e., a center line average (CLA) value of about 1.6. Advantageously, a surface finish of about 1.6 or greater does not require grinding the surface; however, surface grinding may be used to provide a surface finish of about 1.3. The contact surfaces of the labyrinth seals and the labyrinth seal retainers can have surface finish levels selected to allow close mating without too much wear taking place as they wear in, in part, to preserve the accuracy of the matching labyrinth seals and labyrinth seal retainers' radii tolerance to within about 0.127 mm. While a preferred embodiment of the present invention has a minimum surface finish of about 1.6 thousandths of a millimeter, other suitable surface finish levels ranging from about 1.3 to about 1.8 thousandths of a millimeter can also be used.

The use of currently available non-metallic fiber materials to make labyrinth seals for use with the present invention is undesirable due to the difficulty of machining these materials to close tolerances, because the materials distort under increased temperatures, and because the contact surfaces of these materials do not wear in to become closely matched during the operation of the dust seal assembly. The labyrinth seals and, optionally, labyrinth seal retainers, are machined to a close tolerance and are slidingly fit on the cone crusher inner bonnet. In a preferred embodiment, there is only a few thousandths of one inch of clearance between the labyrinth seals and the cone crusher inner bonnet. Ideally, the minimal clearance between the labyrinth seals and the cone crusher inner bonnet permits just enough room to allow assembly of the labyrinth seals and the cone crusher inner bonnet when the cone crusher shaft assembly is lowered into the bottom shell of the cone crusher.

In one embodiment involving flat head cone crushers, the attachment assembly used to secure the multiple labyrinth seals and labyrinth seal retainers to the cone head comprises high tensile bolting. In a preferred embodiment, the labyrinth seal retainers are attached to the lower, or bottom, surface of the cone head using high tensile bolts. The high tensile bolts are pre-loaded to approximately 75% of the bolt yield load. The preferred bolt attachment assembly advantageously also permits the ready disassembly to facilitate maintenance of the cone crusher. The labyrinth seal retainers are also located within the cone head by hardened dowels. The hardened dowels of the present invention are preferably located on different pitch circle diameters for each dust seal retainer, so that the wrong radius retainer cannot be assembled with the wrong radius dust seal ring. For example, in a horizontal labyrinth dust seal system, the hardened dowels ensure that an upper dust seal retainer can only be fitted in an upper position (i.e., mating with the cone head), and that a lower dust seal retainer can only be fitted in a lower position (i.e., mating with the upper dust seal retainer). In a preferred embodiment, there are two one-inch diameter hardened dowels in each retainer. Both of these hardened dowels are interference fits in the cone head and are a fine clearance fit in the mating parts.

In another embodiment of the invention for use in either flat head cone crushers or steep head cone crushers, the attachment assembly used to secure the multiple labyrinth seals and labyrinth seal retainers to the inner bonnet comprises use of a clamp ring that may, optionally, double as an oil baffle. In a preferred

embodiment, at least one labyrinth seal retainer is attached to the inner bonnet using a clamp ring that is also an oil baffle. This embodiment also secures the labyrinth seals by use of an outer bonnet which provides an outer boundary for labyrinth seal movement, preferably fixedly attached to the cone head using high tensile bolting. The high tensile bolts are pre-loaded to approximately 75% of the bolt yield load. The preferred bolt attachment assembly advantageously also permits ready disassembly to facilitate maintenance of the cone crusher.

In a preferred embodiment, the cone crusher inner bonnet is made from a medium carbon steel that is hardened and tempered to 240/260 BHN. The outside diameter of the cone crusher inner bonnet provides an interface surface with the inner circumference of the labyrinth seal bores and is machined to provide a smooth surface finish and a close clearance fit with a tolerance range of about 0.229 mm maximum, to about 0.076 mm minimum.

In a preferred embodiment, the cone crusher inner bonnet houses a pressurized air supply line. Thereby, pressurized air can be injected directly into the cone crusher dust seal assembly through ports in the cone crusher inner bonnet. In a preferred embodiment, the target air pressure to be maintained inside the crusher is about 0.035 kg per square centimeter to about 0.069 kg per square centimeter above atmospheric pressure. The number of ports provided in the cone crusher inner bonnet may vary; however, in a preferred embodiment, the cone crusher inner bonnet includes four such ports set apart at equal distances. In a preferred embodiment, each port releases pressurized air directly into the dust seal assembly to provide further insurance against dust entry. The pressurized air can flow through and operate against dust entry at every point where there is clearance between the dust seal assembly components.

In a most preferred embodiment, the cone crusher inner bonnet pressurized air ports are located opposite the inner bore surface of an upper labyrinth seal retainer. Thus, even if dust were to get past a lower labyrinth seal retainer and a lower labyrinth seal, the dust would be unlikely to bypass the additional entrance obstacles provided by the remaining one or more labyrinth seals and labyrinth seal retainers, the cone head sealing lip, and also against positive air flow pressure. Indeed, the positive air flow pressure would work to assist both the prevention of initial dust entry into the dust seal assembly and also reduce the residence time of any dust that may enter by pushing it back out of the dust seal assembly.

The present inventive durable dust seal assembly design provides between about 10,000 hours and about 20,000 hours of operation, more preferably between about 12,000 and about 18,000 hours of operation, and, most preferably, a minimum of at least about 15,000 hours of operation. Advantageously, the present inventive dust seal assembly does not require lubrication, such as oil, grease, or other suitable alternatives. Indeed, the present inventive dust seal assembly is designed to include barriers that exclude the entry of any oil from coming into contact with the seals. By preventing the entry of oil into the dust seal assembly, the present invention avoids not only problems associated with messy oil leaks from the dust seal assembly, but also avoids the possible formation of deleterious oil and dust lapping compounds in the dust seal assembly itself which accelerate dust seal assembly wear.

In a preferred embodiment, the dust seal assembly of the present invention includes barrier components, such as an oil baffle, attached to the bottom surface of the crusher cone head to prevent any oil from the thrust bearing from getting on the cone crusher inner bonnet, and/or an inner bonnet flange which further entraps oil within a substantially confined space. Such barrier component(s) function to further prevent the possibility that any oil may work its way into the dust seal assembly. Also, in a preferred embodiment, there are oil collection drain grooves and drain holes provided within the cone crusher to drain oil away from the dust seal assembly via oil collection groove return lines before it has the opportunity to reach the dust seal assembly.

In a particularly preferred flat head cone crusher embodiment, the crusher has an axially fixed main shaft and the radius of the contact surfaces of the labyrinth seals and the labyrinth seal retainers remain constant as the main shaft gyrates

eccentrically. Accordingly, the contact surfaces of the labyrinth seals and the labyrinth seal retainers wear in to each other perfectly and permanently. Additionally, however, the present invention is designed to include a fine radial clearance fit with a tolerance range of about 0.229 mm maximum radial clearance to about 0.076 mm minimum radial clearance for its component parts (dust seal rings and dust seal inner bonnet) to accommodate slight axial movement of the cone crusher shaft and cone head due to crushing actions (e.g., loaded and unloaded), wear of other cone crusher parts (e.g., a thrust bearing of a hydrostatic bearing system), etc.

In a most preferred embodiment, the present inventive dust seal assembly comprises a double horizontal labyrinth dust seal and is used with a flat head or steep head cone crusher that uses anti- friction roller bearings. BRIEF DESCRIPTION OF THE FIGURES

The accompanying Figures, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments.

Figures 1 A and B Figures 1 A and B provide a front elevation view of a prior art steep head cone crusher, and a close up view of its dust seal component, respectively.

Figures 2A, B, and C Figures 2A, B, and C provide a front elevation view of a flat head cone crusher with a double horizontal labyrinth dust seal according to the present invention, a close up elevation view of the double horizontal labyrinth dust seal, and an additional close up of the hardened dowels used to locate the seal retainers within the cone head.

Figure 3 Figure 3 provides a close up elevation view of a double

horizontal labyrinth dust seal according to the present invention and is provided to depict the specific radii measurements associated with various seal components as described herein.

Figure 4 Figure 4 provides a top plan view of the upper dust seal

contact area and the relative diameters of the inner bonnet, the upper labyrinth seal, and the lower labyrinth seal of a double horizontal labyrinth dust seal according to the present invention, and is provided to depict the measurements associated with these components as described herein.

Figure 5 Figure 5 provides a perspective view of an embodiment of a double horizontal labyrinth dust seal assembly of the present invention.

Figure 6 Figure 6 provides a front elevation view of a flat head cone crusher with a double horizontal labyrinth dust seal of the present invention and details the pressurized air flow according to the present invention.

Figure 7 Figure 7 provides a front elevation view of a flat head cone crusher with a double horizontal labyrinth dust seal of the present invention and details the oil flow according to the present invention.

Figures 8A, B, and C Figures 8A, B, and C provide a front elevation view of an alternative embodiment of a flat head cone crusher with a double horizontal labyrinth dust seal according to the present invention, a close up elevation view of the double horizontal labyrinth dust seal, and an additional close up view of the hardened dowels used to locate the outer bonnet on the cone head.

Figures 9A and B Figures 9A and B provide a front elevation view of another embodiment of the present invention for use with a steep head cone crusher, and a close up view of its dust seal component, respectively.

DETAILED DESCRIPTION OF THE INVENTION

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures.

Figure 1 A provides a front elevation view of a prior art steep head cone crusher 200, including a single labyrinth seal assembly 250. As depicted, the dust seal assembly includes a single labyrinth seal assembly 250 comprising a labyrinth seal retainer 252, a labyrinth seal 254, a cone head dust seal lip 256, and an inner bonnet 258. Pressurized air 260 is injected at a location far from the dust seal assembly, and into the main cavity of the cone crusher.

Figure IB provides a front elevation close up view of a prior art steep head cone crusher 200, including a single labyrinth seal assembly 250.

Because this is a steep head cone crusher, the clearances surrounding the component parts of the dust seal must be large enough to permit the up and down movement of the cone shaft. The maximal overlap of the labyrinth seal retainer 252, labyrinth seal 254 and cone head dust seal lip 256 is about 52.83 mm; however, the minimal overlap of these components is about 23.01 mm. Also, dust could pass up between the inner surface bore of the labyrinth seal 254 and the outside surface diameter of the inner bonnet 258 if wear causes the clearance to get too large, and if there is no pressurized air trying to force its way out through the same opening. Bolts (not depicted) used to attach the labyrinth seal retainer to the cone head are shorter than the bolts used in the present invention, as there is only one labyrinth seal retainer 252 component being fastened to the cone head. Also, unlike the present invention, there is no need for hardened dowels, as there are only the two mating parts which have the same radius at the contact face, such that there is no likelihood that the parts would be mismatched.

For Figures 2-8 pertaining to multiple embodiments of the present invention, the following specific reference identification numbers may be used in the Figures to identify component parts of the dust seal assembly 10 and flat head cone crusher 100: upper labyrinth seal axial clearance 12, upper labyrinth seal 14, top surface of upper labyrinth seal 16, bottom surface of upper labyrinth seal 18, inner bore surface of upper labyrinth seal 20, outer perimeter edge surface of upper labyrinth seal 22, upper labyrinth seal retainer 24, top surface of upper labyrinth seal retainer 26, bottom surface of upper labyrinth seal retainer 28, attachment access hole of upper labyrinth seal retainer 30, inner perimeter edge surface of upper labyrinth seal retainer 32, lower labyrinth seal axial clearance 34, lower labyrinth seal 36, top surface of lower labyrinth seal 38, bottom surface of lower labyrinth seal 40, inner bore surface of lower labyrinth seal 42, outer perimeter edge surface of lower labyrinth seal 44, lower labyrinth seal retainer 46, top surface of lower labyrinth seal retainer 48, bottom surface of lower labyrinth seal retainer 50, attachment access hole of lower labyrinth seal retainer 52, inner perimeter edge surface of lower labyrinth seal retainer 54, bolt 56, bolt recess on the bottom surface of the cone head 58, labyrinth seal retainer dowel 60, fixed lower labyrinth seal retainer support 62, clamp ring 64, flexible dust curtain 66, cone head dust seal lip 68, cone head dust seal lip surface 70, inner perimeter edge of cone head dust seal lip 72, cone head 74, bottom contact surface of cone head 76, cone head oil baffle flange barrier 78, cone head oil baffle flange barrier and inner bonnet flange barrier gap 80, inner bonnet 82, exterior facing surface of inner bonnet 84, inner bonnet flange barrier 86, inner bonnet flange barrier and cone head dust seal lip gap 88, thrust support housing 90, mantle 92, concave 94, cone shaft 96, thrust bearing 98, oil collection groove 102, oil collection groove return line 104, pressurized air supply line 106, air port 108, roller bearings 110, outer bonnet 112, washer(s) 1 16, and set screw(s) 118.

Figures 2A, B, and C provide a front elevation view of a cone crusher with a double horizontal labyrinth dust seal according to the present invention and at varying levels of detail. As depicted, the present inventive dust seal assembly 10 is shown in a flat head cone crusher 100 using roller bearings and comprising a pressurized air supply line. The cone head 74 is shown off center to depict the interaction between the component parts of the inventive dust seal assembly as the cone head 74 undergoes eccentric gyration.

As can be seen, on one side of the cone crusher 100 (opposite the crushing side), the surfaces of the cone head dust seal lip 68, the upper labyrinth seal 14, the upper labyrinth seal retainer 24, the lower labyrinth seal 36, and the lower labyrinth seal retainer 46 are substantially overlapping. On the opposite side of the cone crusher (the crushing side), the surfaces of the cone head dust seal lip 68, the upper labyrinth seal 14, the upper labyrinth seal retainer 24, the lower labyrinth seal 36, and the lower labyrinth seal retainer 46 are still overlapping, but include three enlarged clearance spaces where the upper labyrinth seal 14 and the lower labyrinth seal 36 engage the upper labyrinth seal retainer 24 and the lower labyrinth seal retainer 46, respectively, and where the upper labyrinth seal retainer 24 and the lower labyrinth seal retainer 46 slide out from underneath the upper labyrinth seal 14 and the lower labyrinth seal 36, respectively. The maximum dust seal overlap provided by the cone head dust lip, the labyrinth seals, and the labyrinth seal retainers is about 90 mm. The minimum dust seal overlap provided by the cone head dust lip, the labyrinth seals, and the labyrinth seal retainers is about 35.6 mm. The inner bonnet flange barrier and cone head dust seal lip gap 88 is also enlarged to accommodate gyration of the cone head.

As the cone head 74 eccentrically gyrates, the non-crushing side of the cone crusher 100 provides the maximum amount of overlapping surface areas between the cone head dust seal lip 68, the upper labyrinth seal 14, the upper labyrinth seal retainer 24, the lower labyrinth seal 36, and the lower labyrinth seal retainer 46 dust seal assembly components, and minimum clearance spaces between these

components. Accordingly, at any one time during the gyration of the cone head 74, the non-crushing side of the cone head 74 delivers maximal dust seal protection due to the severely restricted clearance space and the maximally extended surface area distances that would need to be overcome by dust in order to gain entrance into the cone crusher 100.

The crushing side of the cone crusher 100, even though its configuration results in reduced overlapping surface areas between the cone head dust seal lip 68, the upper labyrinth seal 14, the upper labyrinth seal retainer 24, the lower labyrinth seal 36, and the lower labyrinth seal retainer 46 dust seal assembly components, and maximally enlarged clearance spaces between these components, still provides formidable resistance to dust entry in the form of still substantial overlapping surface distance areas that would need to be overcome by dust in order to gain entrance into the cone crusher 100.

Additional physical barriers to dust entry and/or oil creep that are continuously present regardless of the rotational position of the cone head 74 include the inner bonnet flange barrier 86 and the cone head oil baffle flange barrier 78. In the depicted embodiment, pressurized air injected into the dust seal assembly 10 via an air port 108 provided in the inner bonnet 82 opposite the upper labyrinth seal retainer 24 provides positive air pressure within the dust seal assembly 10 that also counteracts the entrance of dust.

Also, during operation, the rapid eccentric gyration of the cone head 74, which may be approximately 300 gyrations per minute, and may range between about 280 to 330 gyrations per minute, results in the rapid movement of the upper labyrinth seal retainer 24 and the lower labyrinth seal retainer 46, and the respective upper labyrinth seal 14 and the lower labyrinth seal 36, from the crushing side position to the noncrushing side position such that any dust that gained entrance would effectively have to overcome at least the severely restricted clearance space and the minimally extended surface area distances of the dust seal assembly components in the crushing side position (of about 35.6 mm as noted above). Meanwhile, in the depicted embodiment, the pressurized air directly injected into the dust seal assembly would also provide a continuous force working to counteract any dust entry.

As shown, the upper labyrinth seal retainer 24 and the lower labyrinth seal retainer 46 are secured to the bottom surface of the cone head by a bolt 56. In this preferred embodiment there are sixteen one -inch diameter bolts and hardened friction grip washers. The attachment access holes 30 and 52 in the labyrinth seal retainers have a diameter of 27 mm. The bolt 56 used to attach the upper labyrinth seal retainer 24 and the lower labyrinth seal retainer 46 penetrates the attachment access holes 30 and 52 of each retainer and mounts into a recess 58 provided on the bottom surface of the cone head 74. The recess 58 provided on the bottom surface of the cone head 74 is a full thread tap to a minimum depth of 30 mm. The depth of the bolt in the recess 58 is specified as being a minimum of 25.4 mm. As depicted, the recess 58 provided on the bottom surface of the cone head 74 is located near its outer perimeter edge.

The upper labyrinth seal 14, the upper labyrinth seal retainer 24, the lower labyrinth seal 36, and the lower labyrinth seal retainer 46 are spherical in shape and have convex and concave mating surfaces, respectively. The labyrinth seal retainers are medium carbon steel. The labyrinth seals are one of bronze or spheroidal graphite cast iron. The upper labyrinth seal 14 and the lower labyrinth seal 36 are loose, but are supported by and in contact with the top surface of the upper labyrinth seal retainer 26 and the top surface of the lower labyrinth seal retainer 48, respectively. Both the top surface of the upper labyrinth seal 16 and the top surface of the lower labyrinth seal 38 have a small axial clearance of between about 1.27 mm and about 1.524 mm above their respective top surfaces. The axial clearance between the top surface of the upper labyrinth seal 16 and the cone head dust seal lip 68 is nominal, at about 1.27 mm.

The inner bore surfaces of the upper labyrinth seal 14 and the lower labyrinth seal 36 are machined to a close tolerance of about 37.444 mm maximum to about 37.441 mm minimum and are slidingly fit on the cone crusher inner bonnet 82. As depicted, the inner bore surface of the upper labyrinth seal 20 and the inner bore surface of the lower labyrinth seal 42 interface with an exterior facing surface of the inner bonnet 82, and have a clearance fit ranging from about 0.23 mm maximum, to about 0.08 mm minimum.

The attachment assembly includes the bolt 56 used to secure the upper labyrinth seal 14, the upper labyrinth seal retainer 24, the lower labyrinth seal 36, and the lower labyrinth seal retainer 46 to the bottom surface of the cone head 74. The labyrinth seal retainers are also located within the cone head 74 by hardened labyrinth seal retainer dowels 60. In one embodiment, the upper labyrinth seal retainer 24 is located in the cone head 74, and the lower labyrinth seal retainer 46 is located in the upper labyrinth seal retainer 24 by hardened dowels 60.

The cone crusher inner bonnet 82 houses a pressurized air supply line 106 that directly injects air into the cone crusher dust seal assembly 10 through ports in the cone crusher inner bonnet. Here, the cone crusher inner bonnet 82 includes four pressurized air ports, including air port 108 located opposite the inner perimeter edge surface of upper labyrinth seal retainer 32. Also shown are additional dust entry barrier components, such as a cone head oil baffle flange barrier 78, attached to the bottom contact surface of the crusher cone head 76 to prevent any oil from thrust bearing 98 from getting on the cone crusher inner bonnet 82, and an inner bonnet flange barrier 86 that serves to entrap oil within a substantially confined space. Also, an oil collection groove 102 and an oil collection groove return line 104 are shown, which serve to drain oil away and prevent oil movement towards the dust seal assembly.

Figure 3 provides a close up elevation view of a double horizontal labyrinth dust seal according to the present invention and is provided to depict the specific radii measurements associated with various seal components as described herein. 150 depicts the cone head having a radius of about 870.8 mm. 152 depicts the upper labyrinth seal having a radius of about 872.11 mm. 154 depicts the upper labyrinth seal and upper labyrinth seal retainer having a radius of about 893.52 mm. 156 depicts the upper labyrinth seal retainer having a radius of about 914.83 mm. 158 depicts the lower labyrinth seal having a radius of about 916.46 mm. 160 depicts the lower labyrinth seal and lower labyrinth seal retainer having a radius of about 938.28 mm. 162 depicts the lower labyrinth seal retainer having a radius of about 959.74 mm.

Figure 4 provides a plan view of the upper dust seal contact area 170 and the relative diameters of the inner bonnet, the upper labyrinth seal, and the lower labyrinth seal of a double horizontal labyrinth dust seal according to the present invention, and is provided to depict the measurements associated with these components as described herein. Specifically, the inner bonnet's outer diameter 172, the upper dust seal inner diameter 174, the upper dust seal outer diameter 176, and the dust seal retainer ring inner diameter 178 are identified. The lower dust seal inner diameter and the lower dust seal outer diameter are substantially identical to the upper dust seal inner diameter 174 and the upper dust seal outer diameter 176.

Figure 5 provides a perspective view of an embodiment of a double horizontal labyrinth dust seal assembly of the present invention. The components specifically identified in the Figure use and correspond to the reference identification numbers defined elsewhere in this application.

Figure 6 provides a front elevation view of a flat head cone crusher 100 with a double horizontal labyrinth dust seal of the present invention and details the pressurized air flow, as depicted by the arrows, according to the present invention. The pressurized air supply line 106 is shown to enter into the cone crusher, and pressurized air is released from air port 108 into the space opposite the inner perimeter edge surface of upper labyrinth seal retainer 32.

Figure 7 provides a front elevation view of a flat head cone crusher 100 with a double horizontal labyrinth dust seal of the present invention and details the oil flow, as depicted by the arrows, according to the present invention. As shown, oil flows from an external source into the flat head cone crusher 100. Oil flows through the thrust support housing 90 to thrust bearing 98 where it flows out onto bottom contact surface of cone head 76. As the cone head 74 gyrates, oil is distributed along the bottom contact surface of cone head 76. Some of this oil flows outward towards the cone head oil baffle flange barrier 78 and into the cone head oil baffle flange barrier and inner bonnet flange barrier gap 80. Oil in the cone head oil baffle flange barrier and inner bonnet flange barrier gap 80 is directed towards the oil collection groove 102 and the oil collection groove return line 104. The inner bonnet flange barrier 86 serves to trap oil in the cone head oil baffle flange barrier and inner bonnet flange barrier gap 80 and assists in directing this oil into the oil collection groove 102 and the oil collection groove return line 104. Oil is blocked and directed away from possible entry into the double labyrinth dust seal assembly.

Figures 8A, B, and C provide a front elevation view of a cone crusher with a double horizontal labyrinth dust seal according to the present invention and at varying levels of detail. As depicted, the present inventive dust seal assembly 10 is shown in a flat head cone crusher 100 using roller bearings and comprising a pressurized air supply line. The cone head 74 is shown off center to depict the interaction between the component parts of the inventive dust seal assembly as the cone head 74 undergoes eccentric gyration.

As can be seen, on one side of the cone crusher 100 (opposite the crushing side), the surfaces of the upper labyrinth seal 14, the upper labyrinth seal retainer 24, the lower labyrinth seal 36, and the lower labyrinth seal retainer 46 are substantially overlapping. On the opposite side of the cone crusher (the crushing side), the surfaces of the upper labyrinth seal 14, the upper labyrinth seal retainer 24, the lower labyrinth seal 36, and the lower labyrinth seal retainer 46 are still overlapping, but include three enlarged clearance spaces where the upper labyrinth seal 14 and the lower labyrinth seal 36 engage the upper labyrinth seal retainer 24 and the lower labyrinth seal retainer 46, respectively, and where the upper labyrinth seal 14 and the lower labyrinth seal 36 slide above the upper labyrinth seal retainer 24 and the lower labyrinth seal retainer 46, respectively.

The mechanism of operation for this embodiment is similar to that shown, for example, in Figures 2 A, B, and C.

Notably, however, unlike the inventive embodiment generally depicted in

Figures 2A, B, and C, in this alternative embodiment of the double labyrinth dust seal for use with flat head cone crushers, at least the upper labyrinth seal retainer 24 is fixed to the inner bonnet 82 instead of to the cone head 74.

That is, here, the upper labyrinth seal retainer 24 and the lower labyrinth seal retainer 46 are not directly connected to the cone head 74, but are instead directly associated with the inner bonnet 82. Here, both the upper labyrinth seal 14 and the lower labyrinth seal 36 are independent seal rings that can be replaced without affecting any other components. This alternative embodiment advantageously provides a simple way to access and replace, if needed, the upper labyrinth seal 14 and the lower labyrinth seal 36.

In this alternative embodiment, the upper labyrinth seal retainer 24 is clamped onto, or otherwise fixedly attached to, the inner bonnet 82. As depicted, the clamp ring 64 for the upper labyrinth seal retainer 24 is also an oil baffle. The outer bonnet 112 is used to locate, and provide a boundary to, the upper labyrinth seal 14 and the lower labyrinth seal 36. The bottom surface of upper labyrinth seal 18 and the bottom surface of lower labyrinth seal 40 each mate with one of either the top surface of the upper labyrinth seal retainer 26 and the top surface of lower labyrinth seal retainer 48, respectively. The lower labyrinth seal retainer 46, generally, and the bottom surface of lower labyrinth seal retainer 50, specifically, contacts and is fully supported by a fixed lower labyrinth seal retainer support 62. The mating surfaces of the bottom surface of lower labyrinth seal retainer 50 and the fixed lower labyrinth seal retainer support 62 are spherical.

In this alternative embodiment, the outer bonnet 112 is bolted to the cone head 74 using S AE grade 8 high tensile set screws with a friction grip washer to the bottom surface of the cone head 58. These bolts are pre-tensioned to 75% of yield.

The outer bonnet 112 is a very fine clearance fit on the shoulder of the machined face of the bottom surface of the cone head 58. There is also a dowel 60 locating the outer bonnet 112 on the cone head 74. The inner bore of the cone head 74 is a ground surface finish with a CLA rating of 0.8, or better, to give a very close clearance fit on the outside diameter of the upper labyrinth seal 14 and the lower labyrinth seal 36 to provide maximum effective dust sealing.

The lower end of the inner bore of the outer bonnet 112 is machined with a taper 1 14, to help the entrance of the upper labyrinth seal 14 and the lower labyrinth seal 36 into the outer bonnet 112 when the cone head assembly is being lowered into position. At the bottom end of the outer bonnet 112, there is a flexible dust curtain 66 which is fastened to the outer bonnet 112 with, for example, a clamp ring and set screws 118 with a standard washer 116. Loctite™ is used on the set screw threads to ensure the screws do not loosen. The material for the outer bonnet 112 is a medium carbon cast steel, hardened and tempered to 290/300 BHN. The upper labyrinth seal 14 and the lower labyrinth seal 36 are a very close clearance fit inside the bore of the outer bonnet 112 for maximum dust exclusion.

The bottom surface of upper labyrinth seal 18 and the bottom surface of lower labyrinth seal 40 are machined spherical to mate with the same spherical radius as is on the top surface of upper labyrinth seal retainer 26 and the top surface of lower labyrinth seal retainer 48, respectively. Each of the contact faces (18, 40, 26, and 48) is sprayed with a molybdenum disulphide air drying compound at assembly. The upper labyrinth seal 14 and the lower labyrinth seal 36 are made of medium carbon steel and hardened and tempered to approximately 250 BHN. The material for the upper labyrinth seal retainer 24 and the lower labyrinth seal retainer 46 is spheroidal graphite iron.

The lower labyrinth seal retainer 46 sits on the fixed lower labyrinth seal retainer support 62. The contact faces between the lower labyrinth seal retainer 46 and the fixed lower labyrinth seal retainer support 62 are mating spherical radii. Both the lower labyrinth seal retainer 46 and the fixed lower labyrinth seal retainer support 62 are a very fine clearance fit on the outside diameter of the inner bonnet 82, and the fixed lower labyrinth seal retainer support 62 is fixed to the inner bonnet 82 with Unbrako™ alien head set screws and hardened washers. The threads are treated with Loctite™ at assembly.

The upper labyrinth seal retainer 24 is a very fine clearance fit on the outside diameter of the inner bonnet 82 and is clamped in place using clamp ring 64 (which, as shown here, is also an oil baffle) and fastened with set screws and standard washers, and the threads are treated with Loctite™ at assembly. There is a gap between the bottom surface of upper labyrinth seal retainer 28 and the top surface of lower labyrinth seal 38 of approximately 2 mm.

Figures 9A and B provide front elevation views of a steep head cone crusher 300, including a double labyrinth seal assembly 350 according to the present invention. As depicted, the dust seal assembly includes a double labyrinth seal assembly 350 configuration, similar to that described above in connection with Figures 8A, B, and C, in so far as upper labyrinth seal retainer 324 and the lower labyrinth seal retainer 346 are associated with the inner bonnet 358 instead of the cone head 374.

In this embodiment, there is an upper labyrinth seal retainer 324 and a lower labyrinth seal retainer 346 located on inner bonnet 358, and an upper labyrinth seal 314 and a lower labyrinth seal 336 that are located within and contained by the outer bonnet 368. In this embodiment, the upper labyrinth seal 314 and a lower labyrinth seal 336 are a very close fit inside the outer bonnet 368 to achieve dust exclusion, but there is sufficient clearance to allow the outer bonnet 368 to move up and down with the shaft, sliding over the upper labyrinth seal 314 and a lower labyrinth seal 336, as the shaft is adjusted upwards for wear, or moves down to relieve pressure in an overload situation.

This double labyrinth steep head cone crusher configuration increases the contact length of the cone head 374 on the shaft, and thus reduces the amount of cantilever the crushing force has on the lower end of the cone head 374. Also, in this embodiment, the shaft advantageously has an extended taper and an increased diameter of the shaft in a highly stressed area of the steep head cone crusher.

The outer bonnet 368 is bolted to the cone head using SAE grade 8 high tensile set screws with a friction grip washer. These bolts are pre-tensioned to 75% of yield. The outer bonnet 368 is a very fine clearance fit on the shoulder of the machined face on the bottom contact surface of the cone head 376. The inner bore of the outer bonnet 368 is a ground surface finish with a CLA rating of 0.8, or better, to give a very close clearance fit on the outside diameter of an upper labyrinth seal 314 and a lower labyrinth seal 336 to provide maximum effective dust sealing. The lower end of the inner bore of the outer bonnet 368 is machined with a taper, to help the entrance of an upper labyrinth seal 314 and a lower labyrinth seal 336 into the outer bonnet 368 when the cone head and shaft assembly is being lowered into position. The outer bonnet 368 is a medium carbon cast steel, hardened and tempered to 290/300 BHN. The top surface of upper labyrinth seal retainer 316 and the top surface of lower labyrinth seal retainer 338 are machined spherical to mate with the same spherical radius as is on the bottom surface of the upper labyrinth seal 328 and the bottom surface of the lower labyrinth seal 352, respectively. Each of the contact faces (316, 338, 328, and 352) is sprayed with a molybdenum disulphide air drying compound at assembly. The upper labyrinth seal 314 and the lower labyrinth seal 336 are made of a high grade spheroidal graphite iron. The material for the upper labyrinth seal retainer 324 and a lower labyrinth seal retainer 346 is a medium carbon steel, hardened and tempered to approximately 250 BHN.

The lower labyrinth seal retainer 346 sits on the lower dust seal ring support base ring which is part of the inner bonnet 358. The contact faces between the lower labyrinth seal retainer 346 and the lower dust seal ring support base ring which is part of the inner bonnet 358 are machined flat surfaces. Both the lower labyrinth seal retainer 346 and the lower dust seal ring support base ring which is part of the inner bonnet 358 are a very fine clearance fit on the outside diameter of the inner bonnet 358. The lower labyrinth seal retainer 346 is fixed to the inner bonnet 358 with Unbrako™ alien head set screws and hardened washers. The threads are treated with Loctite™ at assembly.

The upper labyrinth seal retainer 324 is a very fine clearance fit on the outside diameter of the inner bonnet 358 and is clamped in place using clamping ring (and baffle) 366 and fastened with set screws and standard washers, and the threads are treated with Loctite™ at assembly. There is a gap between the bottom surface of upper labyrinth seal retainer 328 and the top surface of lower labyrinth seal 338 of approximately 2 mm. The inner bonnet 358 is bolted to the bottom shell hub using SAE grade 8 high tensile set screws with a friction grip washer. These bolts are pre- tensioned to 75% of yield. The inner bonnet 358 is a very fine clearance fit inside the bottom shell hub. The material of the inner bonnet 358 is a medium carbon cast steel.

Pressurized air 360 is injected at a location distant from the dust seal assembly, and into the main cavity of the cone crusher.

Figure 9B provides a front elevation close up view of a steep head cone crusher 300, including a single labyrinth seal assembly 350.

While the inventors have disclosed the preferred embodiments of their multiple labyrinth dust seal invention, they do not confine themselves to any particular form of the multiple labyrinth dust seal. Additionally, the multiple labyrinth dust seal may take on various forms without deviating from the spirit of this invention.

Claims

1. A double labyrinth dust seal assembly for a cone crusher comprising:

two non-fixed labyrinth seals;

two labyrinth seal retainers; and

wherein the non- fixed labyrinth seals and the labyrinth seal retainers are closely matched spherical shapes comprised of compatible low-friction materials.

2. The double labyrinth dust seal assembly of claim 1, further comprising

positive air pressure delivered directly within the dust seal assembly.

3. The double labyrinth dust seal assembly of claim 1, wherein the cone crusher is a flat head cone crusher.

4. The double labyrinth dust seal assembly of claim 1, wherein the cone crusher is a steep head cone crusher.

5. The double labyrinth dust seal assembly of claim 1, wherein the dust seal assembly is substantially without lubricant.

6. The double labyrinth dust seal assembly of claim 1, wherein the non- fixed labyrinth seals and the labyrinth seal retainers are positioned in a substantially horizontal configuration.

7. The double labyrinth dust seal assembly of claim 3, further comprising: an attachment assembly that secures the entire weight of the non- fixed labyrinth seals and the labyrinth seal retainers to a cone head; and

an inner bonnet interfacing with the non-fixed labyrinth seals and the labyrinth seal retainers.

8. The double labyrinth dust seal assembly of claim 3, further comprising: an attachment assembly that secures the entire weight of the non- fixed labyrinth seals and the labyrinth seal retainers to an inner bonnet; and

the inner bonnet interfacing with the non- fixed labyrinth seals and the labyrinth seal retainers.

9. The double labyrinth dust seal assembly of claim 4, further comprising: an attachment assembly that secures the entire weight of the non- fixed labyrinth seals and the labyrinth seal retainers to an inner bonnet; and

10. The double labyrinth dust seal assembly of claim 6, wherein each of the non- fixed labyrinth seals has a convex mating surface and each of the labyrinth seal retainers has a concave mating surface.

11. The double labyrinth dust seal assembly of claim 6, wherein the non- fixed labyrinth seals and the labyrinth seal retainers comprise either substantially the same radius or exactly the same radius.

12. The double labyrinth dust seal assembly of claim 11, further comprising a large contact area between the non- fixed labyrinth seals and the labyrinth seal retainers.

13. The double labyrinth dust seal assembly of claim 11, further comprising a small axial clearance of between about 1.27 mm to about 1.52 mm between at least one upper surface of one of the non-fixed labyrinth seals and at least one bottom surface of one of the labyrinth seal retainers.

14. The double labyrinth dust seal assembly of claim 6, wherein the labyrinth seal retainers and the non- fixed labyrinth seals comprise one of a steel and a steel compatible material, wherein compatibility is characterized by a low surface friction with the steel and the ability to wear in to the shape of the steel.

15. The double labyrinth dust seal assembly of claim 14, wherein the steel

compatible material is at least one of bronze and spheroidal graphite cast iron.

16. A method of using the double labyrinth dust seal assembly of claim 1 to

prevent the entry of dust into the cone crusher.

17. The method of claim 16, further comprising using the double labyrinth dust seal assembly in a cone crusher with roller bearings.

18. The method of claim 16, for use with one of a flat head cone crusher and a steep head cone crusher.

19. The method of claim 16, further comprising preventing formation of lapping components and excluding the use of lubricant.

20. The method of claim 16, further comprising introducing air pressure into the double labyrinth dust seal assembly.