Patent Description:
Conventionally, there is known an expansion joint included in equipment for treatment of powdery or granular materials and used at a connection point where displacement between connected parts occurs, such as at a point of connection between a vibrator and a pipe. The present applicant has proposed such a kind of expansion joint in Patent Literature <NUM>.

The expansion joint of Patent Literature <NUM> and Patent Literature <NUM> includes an outer tube, an inner tube located inside the outer tube, and an elastic closure (bellows) closing a gap between the upstream ends of the inner and outer tubes. The downstream end of the outer tube is connected to a downstream pipe, and the upstream end of the inner tube is connected to an upstream pipe. The upstream ends of the inner and outer tubes are located at substantially the same height. In the expansion joint of Patent Literature <NUM> and Patent Literature <NUM>, the downstream end of the inner tube and the closure are far enough from each other to prevent contact between the closure and a hot transferred material getting in between the inner and outer tubes. Patent Literature <NUM> discloses a flange of a piping fastened to a flange of an inner pipe, while a flange of another piping is joined with a flange of an external pipe, wherein a packing is set in while contacting the inside surface of the external pipe and the outer surface of the inner pipe, wherein the inner pipe slides on the packing as an expansion joint for piping capable of expanding and contracting. Patent Literature <NUM> discloses an expansion joint including first and second conduits connected by an expansion joint element, wherein the second conduit has a liner portion which protrudes into the first conduit, so that the expansion joint element, first conduit, second conduit and liner portion together define an expansion joint cavity, wherein a cartridge is located within the expansion joint cavity and is affixed to an end portion of the first conduit, wherein the cartridge has a groove which faces the liner portion and houses a ring which slides within the groove while maintaining sliding contact with the liner portion of the second conduit. Patent Literature <NUM> discloses a flexible coupling pipe for interconnecting pipe lines, comprising an inlet pipe provided at its inlet end with a flange for connection with the end of one of the pipe lines to be interconnected, an outlet pipe provided at its outlet end with a flange for connection with the end of the other pipe line to be interconnected, and a flexible barrel-shaped central pipe secured to and bridging the inlet and outlet pipes, the inner diameter of at least one of the inlet and outlet pipes converging in the direction from the inlet to the outlet of the coupling pipe.

Expansion joints are inserted between upstream and downstream pipes placed beforehand. Expansion joints are heavy, and may be located at great heights or in narrow places. With the use of the expansion joint of Patent Literature <NUM> in such a situation, the expansion joint mounting work including connecting the inner tube to the upstream pipe and attaching the closure could be cumbersome because the upstream end of the outer tube, the upstream end of the inner tube, and the downstream end of the upstream pipe are located at substantially the same height.

The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to propose an expansion joint in which the downstream end of an inner tube and a closure are far enough from each other and which can easily be mounted and removed.

An expansion joint according to one aspect of the present disclosure is an expansion joint that absorbs displacement occurring at a point of connection between upstream and downstream pipes through which a powdery and/or granular material is transferred by gravity, the expansion joint including:.

Incineration ash treatment equipment according to one aspect of the present disclosure includes: a vibrator that treats incineration ash; a pipe that delivers the incineration ash to the vibrator; and the expansion joint as defined above, the expansion joint being located between an outlet of the pipe and an inlet of the vibrator.

In the expansion joint and incineration ash treatment equipment configured as described above, the middle flange, to which the closure is attached, is spaced from the fourth end (i.e., downstream end) of the inner tube in the axial direction. Thus, the fourth end of the inner tube and the closure can be spaced a distance corresponding to the distance between the fourth end and middle flange of the inner tube in the axial direction. This can reduce the likelihood that the transferred material entering the gap between the inner tube and the outer tube from the fourth end of the inner tube comes into contact with the closure <NUM>.

In the expansion joint and incineration ash treatment equipment configured as described above, the first flange located at the first end of the outer tube and the third flange located at the third end of the inner tube are spaced from each other in the axial direction. The space between the first flange and the third flange in the axial direction can be used as a workspace for connection (or disconnection) of the third flange and the upstream pipe. Thus, connection and disconnection of the expansion joint and the upstream pipe can easily be performed.

In the expansion joint and incineration ash treatment equipment configured as described above, the third end of the inner tube connected to the upstream pipe and the first end of the outer tube are spaced from each other in the axial direction. Thus, the dimension of the outer tube in the axial direction is smaller than the vertical dimension of a mounting region extending between the upstream pipe and the downstream pipe. As such, the outer tube with the inner tube inserted therein can easily be carried into the mounting region. After the inner tube and the outer tube are placed in the mounting region, the closure can be carried into the mounting region by utilizing a gap between the upstream pipe and the outer tube. Additionally, the space between the third flange and the middle flange in the axial direction can be used as a workspace for attachment (or detachment) of the closure. Thus, attachment and detachment of the closure are easy.

The present disclosure can propose an expansion joint in which the downstream end of an inner tube and a closure are far enough from each other and which can easily be mounted and removed.

Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. <FIG> shows a schematic configuration of incineration ash treatment equipment <NUM> including an expansion joint <NUM> according to an exemplary embodiment of the present disclosure. The incineration ash treatment equipment <NUM> is adapted to finely grind incineration ash generated, for example, in a coal-fired boiler or garbage incinerator.

The incineration ash treatment equipment <NUM> of <FIG> includes a grinder <NUM> that finely grinds incineration ash <NUM>, a conveyor <NUM> that transfers the incineration ash <NUM> to the grinder <NUM>, and a hopper <NUM> that receives the incineration ash <NUM> ground by the grinder <NUM>. A vibrating mill can be used as the grinder <NUM>. In a typical vibrating mill, a grinding medium and a material to be ground collides with each other in a rapidly vibrating drum, and thus the material is finely ground.

The conveyor <NUM> and the grinder <NUM> are connected by a piping system through which the incineration ash <NUM> in the form of grains or aggregates is transferred. The piping system includes a vibrating pipe <NUM> coupled to the inlet of the grinder <NUM>, a fixed pipe <NUM> located upstream of the vibrating pipe <NUM>, and an expansion joint <NUM> connecting the fixed pipe <NUM> to the vibrating pipe <NUM>. The terms "upstream" and "downstream", as used in the specification and the appended claims, respectively refer to upstream and downstream in the direction of flow of the material (incineration ash <NUM>) transferred through the piping system. The fixed pipe <NUM> is an "upstream pipe" for the expansion joint <NUM>, and the vibrating pipe <NUM> is a "downstream pipe" for the expansion joint <NUM>.

The fixed pipe <NUM> is fixed relative to a structure including a device upstream of the grinder <NUM> (the device is, for example, the conveyor <NUM> or an unshown device used for another coal treatment process). The vibrating pipe <NUM> vibrates in conjunction with vibration of the drum of the grinder <NUM>. Thus, displacement occurs at a point of connection between the fixed pipe <NUM> and the vibrating pipe <NUM> due to the vibration of the vibrating pipe <NUM>. The expansion joint <NUM> absorbs the displacement occurring at the point of connection between the fixed pipe <NUM> and the vibrating pipe <NUM>. The expansion joint <NUM> according to the present disclosure is applicable also in the case where both the fixed pipe <NUM> and the vibrating pipe <NUM> are movable.

Hereinafter, the expansion joint <NUM> will be described in detail. <FIG> shows the expansion joint <NUM> according to an exemplary embodiment of the present disclosure and is an end view of the expansion joint <NUM> cut along a plane including the central axis of the expansion joint <NUM>. The expansion joint <NUM> is generally shaped as a solid of revolution. The direction in which the axis of revolution extends is referred to as the "axial direction X" of the expansion joint <NUM>, and the axis of revolution is referred to as the "central axis" of the expansion joint <NUM>. The expansion joint <NUM> is mounted in a space between the fixed pipe <NUM> and the vibrating pipe <NUM> in the up-down direction. The space between the fixed pipe <NUM> and the vibrating pipe <NUM> in the up-down direction will be referred to as a "mounting region A" hereinafter. When the vibrating pipe <NUM> is at rest, a straight line drawn between the center of the opening of the fixed pipe <NUM> and the center of the opening of the vibrating pipe <NUM> is parallel to the axial direction X of the expansion joint <NUM>.

The expansion joint <NUM> of <FIG> includes an outer tube <NUM>, an inner tube <NUM> located inside the outer tube <NUM>, and a closure <NUM> closing a gap between the outer tube <NUM> and the inner tube <NUM>. The inner circumference of the inner tube <NUM> defines a transfer path <NUM> along which the transferred material (e.g., the incineration ash <NUM>) flows through the expansion joint <NUM>.

<FIG> shows the outer tube <NUM> as viewed in the axial direction X. As shown in <FIG> and <FIG>, the outer tube <NUM> is a metallic tubular body extending from its upstream end (first end) to its downstream end (second end) in the axial direction X. The outer tube <NUM> includes a first flange <NUM> located at the upstream end of the outer tube <NUM>, a second flange <NUM> located at the downstream end of the outer tube <NUM>, a barrel <NUM> connecting the first flange <NUM> to the second flange <NUM>, and a baffle plate <NUM> located on the inner circumference of the barrel <NUM>. Each of the first and second flanges <NUM> and <NUM> includes circumferentially arranged insertion holes. Bolts are inserted into the insertion holes.

The second flange <NUM> is connected to an inlet flange 78a located at the upstream end of the vibrating pipe <NUM>. Between the second flange <NUM> and the inlet flange 78a there is a lower gasket <NUM> that provides hermeticity. The outer tube <NUM> vibrates in conjunction with vibration of the vibrating pipe <NUM>.

The inner diameter D21 of the first flange <NUM> is greater than the inner diameter D22 of the second flange <NUM>. The barrel <NUM> is tapered downward to smoothly connect the first and second flanges <NUM> and <NUM> having different inner diameters. The outer tube <NUM> structured as described above can ensure a range over which the outer tube <NUM> is displaceable relative to the inner tube <NUM> in a direction perpendicular to the axial direction X and at the same time allow for quick movement or transfer of the material from the outer tube <NUM> to the vibrating pipe <NUM>.

The baffle plate <NUM> serves to prevent the transferred material accumulated in the transfer path <NUM> of the expansion joint <NUM> from entering the gap between the outer tube <NUM> and the inner tube <NUM>. The baffle plate <NUM> is shaped as an annular disc and located at approximately the center of the barrel <NUM> in the axial direction X. The inner diameter D24a of the baffle plate <NUM> is greater than the inner diameter D22 of the second flange <NUM>. The outer diameter D24b of the baffle plate <NUM> is smaller than the inner diameter D21 of the first flange <NUM>. The outer periphery of the baffle plate <NUM> is welded to the inner circumferential surface of the barrel <NUM>.

<FIG> shows the inner tube <NUM> as viewed in the axial direction X. As shown in <FIG> and <FIG>, the inner tube <NUM> is a metallic tubular body extending from its upstream end (third end) to its downstream end (fourth end) in the axial direction X. The inner tube <NUM> includes a third flange <NUM> located at the upstream end of the inner tube <NUM>, a barrel <NUM> extending downward from the third flange <NUM>, and a middle flange <NUM> located at a middle portion of the barrel <NUM> in the axial direction X. The middle flange <NUM> includes circumferentially arranged insertion holes. Bolts are inserted into the insertion holes.

The third flange <NUM> is connected to an outlet flange 77a located at the downstream end of the fixed pipe <NUM>. The outer diameter D31 of the third flange <NUM> is smaller than the outer diameter of the outlet flange 77a. The third flange <NUM> is placed between retainers <NUM> and the outlet flange 77a, and the retainers <NUM>, outlet flange 77a, and third flange <NUM> are fastened together by bolts inserted through the retainers <NUM> and the outlet flange 77a. The retainers <NUM> (the number of which is, for example, four) are arranged along the outer periphery of the third flange <NUM>. Each of the retainers <NUM> is shaped as a segment of a ring, and the retainers <NUM> form the ring together. Each of the retainers <NUM> includes a cut at its upper inner periphery, and the third flange <NUM> is fitted in the cut. Thus, the third flange <NUM> of the inner tube <NUM> is restricted from moving relative to the outlet flange 77a of the fixed pipe <NUM> in the radial and up-down directions in the event that the point of connection between the fixed pipe <NUM> and the inner tube <NUM> is subjected to vibration. Each of the retainers <NUM> includes at least one insertion hole 25a for insertion of a bolt. Between the retainers <NUM> and the outlet flange 77a there is an upper gasket <NUM> that provides hermeticity.

The middle flange <NUM> protrudes radially outward from the outer circumferential surface of the barrel <NUM>. The outer diameter D33 of the middle flange <NUM> is greater than the inner diameter D24a of the baffle plate <NUM> and smaller than the outer diameter D24b of the baffle plate <NUM>. To improve the handleability of the inner tube <NUM>, the outer diameter D31 of the third flange <NUM> is desirably smaller than the outer diameter D33 of the middle flange <NUM>.

<FIG> shows the closure <NUM> as viewed in the axial direction X. As shown in <FIG> and <FIG>, the closure <NUM> is shaped as an annular disc. The closure <NUM> includes an inner peripheral portion <NUM>, an outer peripheral portion <NUM>, and an elastic portion <NUM> located between the inner peripheral portion <NUM> and the outer peripheral portion <NUM>. Each of the inner and outer peripheral portions <NUM> and <NUM> includes circumferentially arranged insertion holes. Bolts are inserted into the insertion holes.

The inner diameter D41 of the closure <NUM> is greater than the outer diameter D32 of the barrel <NUM> of the inner tube <NUM> (i.e., the inner diameter of the middle flange <NUM>) and smaller than the outer diameter D33 of the middle flange <NUM>. The outer diameter D42 of the closure <NUM> is greater than the inner diameter D21 of the first flange <NUM> of the outer tube <NUM>.

<FIG> is a view taken along the arrow VI-VI of <FIG>. As shown in <FIG> and <FIG>, the inner peripheral portion <NUM> of the closure <NUM> is connected to the middle flange <NUM> of the inner tube <NUM>. The inner peripheral portion <NUM> is placed between the middle flange <NUM> of the inner tube <NUM> and retainers <NUM>, and the retainers <NUM>, inner peripheral portion <NUM>, and middle flange <NUM> are fastened together by bolts inserted through the retainers <NUM>, inner peripheral portion <NUM>, and middle flange <NUM>. The retainers <NUM> (the number of which is, for example, four) are arranged in a ring along the inner peripheral portion <NUM>. Each of the retainers <NUM> is shaped as a segment of a ring, and the retainers <NUM> form the ring together.

The outer peripheral portion <NUM> of the closure <NUM> is connected to the first flange <NUM> of the outer tube <NUM>. The outer peripheral portion <NUM> is placed between the first flange <NUM> of the outer tube <NUM> and retainers <NUM>, and the retainers <NUM>, outer peripheral portion <NUM>, and first flange <NUM> are fastened together by bolts inserted through the retainers <NUM>, outer peripheral portion <NUM>, and first flange <NUM>. The retainers <NUM> (the number of which is, for example, four) are arranged in a ring along the outer peripheral portion <NUM>. Each of the retainers <NUM> is shaped as a segment of a ring, and the retainers <NUM> form the ring together.

The elastic portion <NUM> is expanded or contracted to absorb displacement of the outer peripheral portion <NUM> relative to the inner peripheral portion <NUM> in the axial direction X and the radial direction. The elastic portion <NUM> shown in <FIG> is made of rubber, resin, or fabric and includes one or more corrugations arranged in the radial direction. The elastic portion <NUM> is not limited to being corrugated. For example, the elastic portion <NUM> of the closure <NUM> may be shaped as a flat sheet insofar as the elastic portion <NUM> is made of elastic rubber or resin. In the case where the material to be transferred is hot, a heat-resistant material is desirably used for the elastic portion <NUM>.

As shown in <FIG>, for the expansion joint <NUM> configured as described above, the dimension of the outer tube <NUM> in the axial direction X is referred to as "outer tube height H2", the dimension of the inner tube <NUM> in the axial direction X is referred to as "inner tube height H3", the dimension of the inner tube <NUM> from its upstream end to the middle flange <NUM> in the axial direction X is referred to as "protrusion height H3a", the dimension of the closure <NUM> in the axial direction X is referred to as "closure height H4", and the dimension of the mounting region A in a direction parallel to the axial direction X is referred to as "mounting region height H0".

The outer tube height H2 is smaller than the mounting region height H0. The sum of the outer tube height H2 and the closure height H4 is desirably smaller than the mounting region height H0.

The inner tube height H3 is smaller than the mounting region height H0. The sum of the inner tube height H3 and the closure height H4 is desirably smaller than the mounting region height H0. The protrusion height H3a is desirably greater than the closure height H4.

The sum of the outer tube height H2, the protrusion height H3a, the thickness of the upper gasket <NUM>, and the thickness of the lower gasket <NUM> is substantially equal to the mounting region height H0.

The following describes how to mount the expansion joint <NUM>. <FIG> illustrate how to mount the expansion joint <NUM>.

First, as shown in <FIG>, the outer tube <NUM> and the inner tube <NUM> are combined into an assembly <NUM>. To construct the assembly <NUM>, the inner tube <NUM> is inserted into the outer tube <NUM> from above. In the assembly <NUM>, the upper surface of the baffle plate <NUM> of the outer tube <NUM> is in contact with the lower surface of the middle flange <NUM> of the inner tube <NUM>. Thus, the inner tube <NUM> is stably supported by the outer tube <NUM> and restricted from moving downward relative to the outer tube <NUM>.

The assembly <NUM> is placed into the mounting region A, and the second flange <NUM> of the outer tube <NUM> is placed onto the inlet flange 78a of the vibrating pipe <NUM>. The dimension of the assembly <NUM> in the axial direction X is referred to as "assembly height H20". The assembly height H20 is smaller than the mounting region height H0 by approximately an extension amount H24 corresponding to the length from the baffle plate <NUM> to the first flange <NUM> in the axial direction X. As the assembly height H20 is smaller than the mounting region height H0, the assembly <NUM> can easily be brought into the mounting region A in a direction perpendicular to the axial direction X.

Next, as shown in <FIG>, the closure <NUM> is placed into the mounting region A. The sum of the assembly height H20 and the closure height H4 is desirably smaller than the mounting region height H0 so that the closure <NUM> can easily be brought into the mounting region A in a direction perpendicular to the axial direction X. As the closure <NUM> is elastically deformable, the size of the gap between the fixed pipe <NUM> and the assembly <NUM> may be slightly smaller than the closure height H4.

Subsequently, as shown in <FIG>, the inner tube <NUM> is raised a distance equal to the extension amount H24 relative to the outer tube <NUM> to bring the third flange <NUM> of the inner tube <NUM> into contact with the outlet flange 77a of the fixed pipe <NUM>. As a result, the location of the middle flange <NUM> of the inner tube <NUM> in the axial direction X becomes approximately the same as the location of the first flange <NUM> of the outer tube <NUM> in the axial direction X.

Afterwards, as shown in <FIG>, the outlet flange 77a of the fixed pipe <NUM> and the third flange <NUM> are fastened by bolts. The inlet flange 78a of the vibrating pipe <NUM> and the second flange <NUM> are fastened by bolts, the inner peripheral portion <NUM> of the closure <NUM> and the middle flange <NUM> are fastened by bolts, and the outer peripheral portion <NUM> of the closure <NUM> and the first flange <NUM> of the outer tube <NUM> are fastened by bolts. The bolt fastening may be performed at any time during the mounting work.

The expansion joint <NUM> can be removed by a reverse procedure to the mounting of the expansion joint <NUM>. That is, the expansion joint <NUM> can be removed from the mounting region A by unfastening the bolts, lowering the inner tube <NUM> toward the outer tube <NUM>, removing the closure <NUM> from the mounting region A, and removing the assembly <NUM> from the mounting region A.

As described above, incineration ash treatment equipment <NUM> according to an exemplary embodiment includes a grinder <NUM> serving as a vibrator that treats incineration ash, a pipe (a fixed pipe <NUM> serving as an upstream pipe) that delivers the incineration ash to the grinder <NUM>, and an expansion joint <NUM> located between an outlet of the pipe and an inlet of the grinder <NUM> (or a vibrating pipe <NUM> serving as a downstream pipe). The expansion joint <NUM> absorbs displacement occurring at a point of connection between the upstream and downstream pipes <NUM> and <NUM> through which a powdery and/or granular material is transferred by gravity. The expansion joint <NUM> includes an outer tube <NUM>, an inner tube <NUM> located inside the outer tube <NUM>, and a closure <NUM> closing a gap between the outer tube <NUM> and the inner tube <NUM>. The outer tube <NUM> includes opposite first and second ends (upstream and downstream ends) and extends from the first end to the second end in an axial direction X of the expansion joint <NUM>. The outer tube <NUM> further includes a first flange <NUM> and a second flange <NUM>, the first flange <NUM> being located at the first end, the second flange <NUM> being located at the second end and connectable to the downstream pipe. The inner tube <NUM> includes opposite third and fourth ends (upstream and downstream ends) and extends from the third end to the fourth end in the axial direction X. The inner tube <NUM> further includes a third flange <NUM> and a middle flange <NUM>, the third flange <NUM> being located at the third end and connectable to the upstream pipe, the middle flange <NUM> being located at a middle portion between the third and fourth ends. The closure <NUM> includes an outer peripheral portion <NUM> connected to the first flange <NUM>, an inner peripheral portion <NUM> connected to the middle flange <NUM>, and an elastic portion <NUM> connecting the outer peripheral portion <NUM> to the inner peripheral portion <NUM>.

In the expansion joint <NUM> according to the above embodiment, the first flange <NUM> of the outer tube <NUM> secured to the downstream pipe <NUM> and the middle flange <NUM> of the inner tube <NUM> secured to the upstream pipe <NUM> are at the same location in the axial direction X. The statement that "the first flange <NUM> and the middle flange <NUM> are at the same location in the axial direction X" is intended to include not only the case where the location of the first flange <NUM> in the axial direction X and the location of the middle flange <NUM> in the axial direction X are exactly the same, but also the case where the distance between the locations of the first flange <NUM> and the middle flange <NUM> in the axial direction X is equal to or below a threshold. For example, the threshold is equal to, and desirably smaller than, the dimension of the closure <NUM> in the axial direction X (i.e., the closure height H4).

The present disclosure is not limited to the expansion joint <NUM> in which the first flange <NUM> of the outer tube <NUM> secured to the downstream pipe <NUM> and the middle flange <NUM> of the inner tube <NUM> secured to the upstream pipe <NUM> are at the same location in the axial direction X. In the expansion joint <NUM>, the first end (upstream end) of the outer tube <NUM> may be spaced from the third end (upstream end) of the inner tube <NUM> in the axial direction X and located between the third end and the fourth end (downstream end) of the inner tube <NUM> in the axial direction X.

In the expansion joint <NUM> and incineration ash treatment equipment <NUM> configured as described above, the middle flange <NUM>, to which the closure <NUM> is attached, is spaced from the fourth end of the inner tube <NUM> in the axial direction X. Thus, the downstream end of the inner tube <NUM> and the closure <NUM> can be spaced a distance corresponding to the distance between the downstream end and middle flange <NUM> of the inner tube <NUM> in the axial direction X. This can reduce the likelihood that the transferred material entering the gap between the inner tube <NUM> and the outer tube <NUM> from the downstream end of the inner tube <NUM> comes into contact with the closure <NUM>.

In the expansion joint <NUM> and incineration ash treatment equipment <NUM> configured as described above, the first flange <NUM> located at the first end of the outer tube <NUM> and the third flange <NUM> located at the third end of the inner tube <NUM> and connected to the upstream pipe <NUM> are spaced from each other in the axial direction X. The space between the first flange <NUM> and the third flange <NUM> in the axial direction X can be used as a workspace for connection (or disconnection) of the third flange <NUM> and the upstream pipe <NUM>. Despite the first flange <NUM> being located radially outside the third flange <NUM>, the work of connecting the third flange <NUM> and the upstream pipe <NUM> is not disturbed by the first flange <NUM>. Thus, connection and disconnection of the expansion joint <NUM> and the upstream pipe <NUM> can easily be performed.

In the expansion joint <NUM> and incineration ash treatment equipment <NUM> configured as described above, the third end (upstream end) of the inner tube <NUM> connected to the upstream pipe <NUM> and the first end (upstream end) of the outer tube <NUM> connected to the downstream pipe <NUM> are spaced from each other in the axial direction X. Thus, the dimension of the outer tube <NUM> in the axial direction X (outer tube height H2) is smaller than the vertical dimension of the mounting region A extending between the upstream pipe <NUM> and the downstream pipe <NUM> (mounting region height H0). As such, the outer tube <NUM> with the inner tube <NUM> inserted therein (i.e., the assembly <NUM>) can easily be carried into the mounting region A. After the assembly <NUM> constructed of the inner tube <NUM> and the outer tube <NUM> is placed in the mounting region A, the closure <NUM> can be carried into the mounting region A by utilizing a gap extending downward from the upstream pipe <NUM> and having a size corresponding to the extension amount H24. Additionally, the space between the third flange <NUM> connected to the upstream pipe <NUM> and the middle flange <NUM> can be used as a workspace for attachment (or detachment) of the closure <NUM>. Thus, attachment and detachment of the closure <NUM> are easy, and this is advantageous not only in mounting/removing work but also in maintenance work in which only the closure <NUM> is replaced by a new one.

In the expansion joint <NUM> and incineration ash treatment equipment <NUM> according to the above embodiment, the downstream end of the inner tube <NUM> and the closure <NUM> are far enough from each other to avoid contact between the transferred material and the closure <NUM>. The expansion joint <NUM> serves the same function as the conventional expansion joint disclosed in Patent Literature <NUM> and is easier to mount and remove than the conventional expansion joint.

In the expansion joint <NUM> according to the above embodiment, the outer diameter D33 of the middle flange <NUM> is greater than the inner diameter D22 of the second flange <NUM> and smaller than the inner diameter D21 of the first flange <NUM>.

Thus, the inner tube <NUM> is stably supported by the outer tube <NUM> in the assembly <NUM> constructed by inserting the inner tube <NUM> into the outer tube <NUM>.

In the expansion joint <NUM> according to the above embodiment, the outer tube <NUM> includes a baffle plate <NUM> shaped as an annular disc that projects radially from an inner circumferential surface of the outer tube <NUM>. Although the baffle plate <NUM> according to the above embodiment is shaped as an annular disc that is circumferentially continuous, the baffle plate <NUM> may be shaped as an annular disc that is circumferentially discontinuous.

The baffle plate <NUM> serves to prevent the transferred material from reaching the closure <NUM> through the gap between the outer tube <NUM> and the inner tube <NUM>. This can reduce the likelihood of contact between the transferred material and the closure <NUM>.

In the above expansion joint <NUM>, the baffle plate <NUM> is located between the middle flange <NUM> and the second flange <NUM> in the axial direction X, and the outer diameter of the middle flange <NUM> is greater than the inner diameter of the baffle plate <NUM> and smaller than the outer diameter of the baffle plate <NUM>.

Thus, in the assembly <NUM> constructed by inserting the inner tube <NUM> into the outer tube <NUM>, the middle flange <NUM> is in contact with, and supported by, the baffle plate <NUM>. As such, the inner tube <NUM> is stably supported by the outer tube <NUM>.

The expansion joint <NUM> according to the above embodiment further includes first retainers <NUM> arranged circumferentially along an outer periphery of the third flange <NUM> to hold the third flange <NUM> between the upstream pipe <NUM> and the first retainers. Each of the first retainers <NUM> includes at least one insertion hole 25a for insertion of a bolt.

The insertion holes through which bolts are inserted to connect the third flange <NUM> to the outlet flange 77a of the upstream pipe <NUM> are included in the first retainers <NUM>, rather than the third flange <NUM>. This eliminates the need to adjust the rotational position of the inner tube <NUM> to align the outlet flange 77a and the third flange <NUM>. Additionally, each of the first retainer <NUM> is not shaped as a circular ring but a segment of a circular ring, and thus the first retainers <NUM> can be arranged around the third flange <NUM> without having to pass the inner tube <NUM> through the central opening of the circular ring formed by the first retainers <NUM>. As such, mounting and removal of the expansion joint <NUM> are simplified.

The expansion joint <NUM> according to the above embodiment further includes second retainers <NUM> arranged circumferentially along the inner peripheral portion <NUM> of the closure <NUM> to hold the inner peripheral portion <NUM> between the middle flange <NUM> and the second retainers <NUM>. The expansion joint <NUM> according to the above embodiment further includes third retainers <NUM> arranged circumferentially along the outer peripheral portion <NUM> of the closure <NUM> to hold the outer peripheral portion <NUM> between the first flange <NUM> and the third retainers <NUM>.

Each of the second retainers <NUM> and the third retainers <NUM> is not shaped as a circular ring but a segment of a circular ring. Thus, the second retainers <NUM> can be arranged along the inner peripheral portion <NUM> of the closure <NUM> without having to pass the outer tube <NUM>, inner tube <NUM>, and closure <NUM> through the central opening of the circular ring formed by the second retainers <NUM>. The third retainers <NUM> can be arranged along the outer peripheral portion <NUM> of the closure <NUM> without having to pass the outer tube <NUM>, inner tube <NUM>, and closure <NUM> through the central opening of the circular ring formed by the third retainers <NUM>.

Although the foregoing has described a preferred embodiment of the present disclosure, the scope of the present disclosure embraces modifications made to the details of the structure and/or function of the above embodiment without departing from the gist of the present disclosure.

For example, although the outer tube <NUM> of the expansion joint <NUM> according to the above embodiment includes the baffle plate <NUM>, the baffle plate <NUM> is not essential and may be omitted.

<FIG> shows an expansion joint 10A according to a first variant and is an end view of the expansion joint 10A cut along a plane including the central axis of the expansion joint 10A. The expansion joint 10A of <FIG> includes an outer tube 2A, which is devoid of the baffle plate <NUM>. In the assembly <NUM> constructed of the outer tube 2A and the inner tube <NUM>, the middle flange <NUM> of the inner tube <NUM> is in contact with the inner circumferential surface of the barrel <NUM> of the outer tube 2A. Thus, the inner tube <NUM> is supported by the outer tube 2A and restricted from moving downward relative to the outer tube 2A. Despite the absence of the baffle plate <NUM>, the likelihood of contact between the transferred material and the closure <NUM> can be reduced since the closure <NUM> is maximally far from a point where the transferred material enters the gap between the inner tube <NUM> and the outer tube 2A.

<FIG> shows an expansion joint 10B according to a second variant and is an end view of the expansion joint 10B cut along a plane including the central axis of the expansion joint 10B. The expansion joint 10B of the <FIG> includes an outer tube 2A, which is devoid of the baffle plate <NUM>. The expansion joint 10B includes an inner tube 3A including a lower flange <NUM> located below the middle flange <NUM>. The lower flange <NUM> protrudes radially outward from the outer circumferential surface of the barrel <NUM>. The outer diameter of the lower flange <NUM> is smaller than the outer diameter D33 of the middle flange <NUM>. In the assembly <NUM> constructed of the outer tube 2A and the inner tube 3A, the lower flange <NUM> of the inner tube <NUM> A is in contact with the inner circumferential surface of the barrel <NUM> of the outer tube 2A. Thus, the inner tube 3A is supported by the outer tube 2A and restricted from moving downward relative to the outer tube 2A. Despite the absence of the baffle plate <NUM>, the likelihood of contact between the transferred material and the closure <NUM> can be reduced since the lower flange <NUM> serves to prevent the transferred material from entering the gap between the inner tube 3A and the outer tube 2A.

Claim 1:
An expansion joint (<NUM>) that absorbs displacement occurring at a point of connection between upstream and downstream pipes (<NUM>, <NUM>) through which a powdery and/or granular material is transferred by gravity, the expansion joint (<NUM>) comprising:
an outer tube (<NUM>) including opposite first and second ends and extending from the first end to the second end in an axial direction (X) of the expansion joint (<NUM>), the outer tube (<NUM>) further including a first flange (<NUM>) and a second flange (<NUM>), the first flange (<NUM>) being located at the first end, the second flange (<NUM>) being located at the second end and connectable to the downstream pipe (<NUM>);
an inner tube (<NUM>) including opposite third and fourth ends and extending from the third end to the fourth end in the axial direction (X), the inner tube (<NUM>) being located inside the outer tube (<NUM>) and further including a third flange (<NUM>), the third flange (<NUM>) being located at the third end and connectable to the upstream pipe (<NUM>); and
a closure (<NUM>) including an outer peripheral portion (<NUM>) connected to the first flange (<NUM>), an inner peripheral portion (<NUM>), and an elastic portion (<NUM>) connecting the outer peripheral portion (<NUM>) to the inner peripheral portion (<NUM>),
characterized in that the inner tube (<NUM>) further includes a middle flange (<NUM>) located at a middle portion between the third and fourth ends, wherein the inner peripheral portion (<NUM>) is connected to the middle flange (<NUM>), wherein the first end is spaced from the third end in the axial direction (X) and located between the third and fourth ends in the axial direction (X).