Patent Application
20130292938
This patent disclosure relates generally to seals and, more particularly, to slip joint seals.
Slip joints are used in many industrial and mechanical applications, particularly in joining pipes. Two pipe segments joined by a slip joint are coupled to one another allowing a fluid connection to be made while allowing axial movement between the pipes. This movement can be caused by various physical forces such as thermal expansion and contraction. Machinery, such as cars, trucks, and other industrial equipment, sometimes utilizes slip joints in exhaust systems due to the thermal expansion and contraction that occurs in those components during operation.
Slip joints have historically encountered leakage of the sealed fluid at the sealed joint. Attempts have been made to stop this leakage using graphite-based seals placed over the joint and held into place by a steel clamp. The graphite seals, however, wear out quickly, resulting in leakage at the slip joint.
The disclosure describes, in one aspect, a slip joint seal including a clamshell clamp. The clamshell clamp includes a generally cylindrical upper portion and a generally cylindrical lower portion that mates with the generally cylindrical upper portion to form a hollow cylindrical ring. The hollow cylindrical ring includes a base portion, a protruding portion, an inner surface, and an outer surface. The clamshell clamp also includes a band that fits around the base portion for securing the generally cylindrical upper and lower portions to one another around the slip joint. The slip joint seal also includes a ceramic fiber filament adapted to discourage leaking from an annular channel formed between an inner pipe and an outer pipe while allowing relative movement between the inner pipe and the outer pipe. The ceramic fiber filament includes a first portion that fits substantially within the base portion and is adapted to be disposed in surrounding relation to a portion of the outer pipe around a slidable interface between the inner pipe and the outer pipe. A second portion fits substantially within the protruding portion and is adapted to be disposed within and substantially fill the annular channel.
In another aspect, the disclosure describes an exhaust system with a slip joint and slip joint seal. The slip joint includes an outer pipe including an accepting end, and the accepting end includes an inner bore. An inner pipe that includes a flange protruding radially away from an outer diameter of the inner pipe. The outer diameter includes a clearance fit when disposed within the inner bore of the accepting end of the outer pipe, and a slidable interface is defined between the inner pipe and the outer pipe. An annular channel extends peripherally around a portion of the inner pipe that is defined between a free end of the outer pipe, an outer surface of the inner pipe, and an annular surface of the flange. The annular channel is peripherally open on the side that is radially away from the inner pipe and is in fluid communication with the slidable interface. The exhaust system also includes a slip joint seal that includes a clamshell clamp. The clamshell clamp includes a generally cylindrical upper portion and a generally cylindrical lower portion that is mateable with the generally cylindrical upper portion to form a hollow cylindrical ring. The hollow cylindrical ring includes a base portion, a protruding portion, an inner surface, and an outer surface. A band fits around the base portion for securing the upper and lower portions to one another around the slip joint. The slip joint seal also has a ceramic fiber filament that discourages leaking from the annular channel while allowing relative movement between the inner pipe and the outer pipe. The ceramic fiber filament includes a first portion that fits substantially within the base portion and is adapted to be disposed in surrounding relation to a portion of the outer pipe around the slidable interface. A second portion fits substantially within the protruding portion and is adapted to be disposed within and substantially fill the annular channel.
In another aspect, the disclosure describes a method for sealing a slip joint including sliding an inner pipe that includes an outer diameter and a flange protruding radially away from the outer diameter at least partially into an inner bore of an accepting end of an outer pipe to form the slip joint between the inner and outer pipes. The outer diameter and inner bore are sized to provide a clearance fit therebetween, such that an annular channel that extends peripherally around a portion of the inner pipe is defined between a free end of the outer pipe, an outer surface of the inner pipe, and an annular surface of the flange. The annular channel is peripherally open on the side that is radially away from the inner pipe and is in fluid communication with a slidable interface. The method also includes assembling upper and lower portions of a clamshell clamp to one another to form a hollow cylindrical ring around the slip joint. The hollow cylindrical ring includes a base portion, a protruding portion, an inner surface, and an outer surface. The method also includes fitting a band around the base portion and securing the upper and lower portions to one another around the slip joint The method also includes installing a ceramic fiber filament around the slip joint that discourages leaking from the annular channel while allowing relative movement between the inner pipe and the outer pipe The ceramic fiber filament includes a first portion and a second portion such that the first portion is substantially within the base portion in surrounding relation to a portion of the outer pipe around the slidable interface, and the second portion is substantially disposed within the protruding portion and extends into and substantially fills the annular channel.
This disclosure relates to a slip joint seal 100. A slip joint is a type of joint that couples two pipe segments in a manner that allows the two pipe segments to move axially with respect to one another.
As material passes through a slip joint, exhaust gas and other particles, such as oil and soot, can leak from the slidable interface 113 between the outer pipe 102 and inner pipe 104 through an annular channel 114 that extends peripherally around a portion of the inner pipe 104. The annular channel 114 is defined between a free end 109 of the outer pipe 102, an outer surface 111 of the inner pipe, and an annular surface 115 of the flange 112. The annular channel 114 is peripherally open on one side that is radially away from the inner pipe 104 and in fluid communication with the slidable interface 113. The interface 113 exists where the outer pipe 102 overlaps the inner pipe 104, which allows the two pipes to slide relative to one another while maintaining a fluid path. The width of the annular channel 114 varies as the inner pipe 104 moves with respect to the outer pipe 102.
As illustrated in
The band has multiple slots 226a, 226b, 227a, 227b formed in the first loop 228 and the second loop 230, respectively. To install the T-bolt 212, the bushing 224 and nut 217 are removed and the T-bolt is inserted through the slots 226 of the first loop 228. The anchor 222 has a larger diameter than the diameter of slot 226b, so the anchor prevents the T-bolt from sliding completely through the first loop 228. The proximate end 221 of the T-bolt passes through slots 227a, 227b such that at least some threads are outside of the second loop 230. The bushing 224 then slides onto the T-bolt 212 at the proximate end 221, and the nut 217 is threaded onto the proximate and behind the bushing. The bushing 224 has a larger diameter than the slot 227b, so the bushing does not pass into the second loop 230. As the nut 217 is tightened, it forces the bushing 224 toward the distal end 223 so it abuts the outside of the second loop 230 As the nut 217 moves the bushing 224 along the T-bolt 212 toward the distal end 223, the bushing engages the second loop and the anchor 222 engages the first loop 228, pulling the two loops toward one another. As the first loop 228 and the second loop 230 are pulled toward one another, the band 210 tightens around the upper portion 206 and the lower portion 208 of the clamshell clamp 202.
In one embodiment of the clamshell clamp 202, the base ring 203 has an inner diameter of about 77.3 mm and an outer diameter of about 87.3 mm. In this embodiment, the cylindrical ring 209 has a thickness of about 20.8 mm to about 21.8 mm, and more specifically 21.3 mm. The band 210 has a width of between about 18.5 mm to about 19.5 mm, more specifically about 19 mm. Additionally, in this embodiment, the clamshell clamp 202 has an effective range of between about 83 mm in diameter to about 105 mm in diameter. In another embodiment of the clamshell clamp 202, the base ring 203 has an inner diameter of about 78.5 mm and an outer diameter of about 83.9 mm. The clamshell clamp 202 in this embodiment has a thickness of about 32.3 mm to about 33.5 mm, and more specifically about 32.8 mm. The band 210 has a width of between about 15.4 mm to about 16.4 mm, more specifically about 15.9 mm. Additionally, in this embodiment, the clamshell clamp 202 has an effective range of about 74.7 mm in diameter to about 82.6 mm in diameter.
As shown in
One way to install an embodiment of the slip joint seal 200 on a slip joint 100 is to insert the filament 204 into the lower portion 208 of the clamshell clamp 202 with the laminate surface 205 facing outward toward the lower portion. The filament 204 is then placed around a portion of the slip joint 100 such that the second portion 216 of the filament fits into the gap 111 between the accepting surface 108 and the stop surface 112. The filament 204 is then wrapped around the remainder of the slip joint 100 and the upper portion 206 of the clamshell clamp 202 is placed over the exposed filament such that the upper portion nests with the lower portion 208. Once the upper portion 206 and lower portion 208 are nested with one another, the band 210 is placed around both the upper portion and lower portion. To tighten the band 210 around the upper portion 206 and lower portion 208, the lock pin 212 and the bushing 224 are rotated with respect to one another to draw the first loop 228 and the second loop 230 towards each other. As a result, the filament 204 is pressed securely around the slip joint 100.
While the arrangement is illustrated in connection with exhaust systems in on-highway trucks, the arrangement disclosed herein has universal applicability in various other types of machines as well. The term “machine” may refer to any machine that performs some type of operation associated with an industry such as mining, construction, farming, transportation, or any other industry known in the art. For example, the machine may be an earth-moving machine, such as a wheel loader, excavator, dump truck, backhoe, motor grader, material handler or the like. Moreover, an implement may be connected to the machine. Such implements may be utilized for a variety of tasks, including, for example, loading, compacting, lifting, brushing, and include, for example, buckets, compactors, forked lifting devices, brushes, grapples, cutters, shears, blades, breakers/hammers, augers, and others.
The industrial application of the apparatus and methods for a slip joint seal in a machine as described herein should be readily appreciated from the foregoing discussion. The present disclosure is applicable to any type of machine utilizing a slip joint. A slip joint generally includes an outer pipe with an accepting end and an inner pipe that includes a flange protruding radially away from an outer diameter of the inner pipe. The outer diameter has a clearance fit when disposed within the inner bore of the accepting end, which defines a slidable interface between the inner pipe and the outer pipe. An annular channel extends peripherally around a portion of the inner pipe defined between a free end of the outer pipe, an outer surface of the inner pipe, and an annular surface of the flange. The annular channel is peripherally open on the side that is radially away from the inner pipe, and is in fluid communication with the slidable interface. The slip joint seal is particularly useful in applications where leakage of particles from a slip joint is undesirable.
The disclosure, therefore, is applicable to many different machines and environments. One exemplary machine suited to the disclosure is an on-highway truck. These trucks are commonly used in many industrial and non-industrial environments and often utilize an exhaust system that include at least one slip joint. In these trucks, the disclosed slip joint seal and methods of using the slip joint are useful in preventing soot and oil from leaking out of the exhaust system slip joints and contaminating the surrounding machinery or environment.
Further, the apparatus and methods described above can be adapted to a large variety of machines. For example, other types of industrial machines using slip joints, such as off-highway trucks, backhoe loaders, compactors, feller bunchers, forest machines, industrial loaders, wheel loaders, tractors and many other machines can benefit from the systems described.
It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.
Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.
