ROTARY REGENERATIVE HEAT EXCHANGER

Abstract

A rotary regenerative heat exchanger has a structure in which a rotor accommodating a heat storage body such as a heat transfer element is rotated inside a housing, the heat storage body is heated by means of a high-temperature heating fluid such as exhaust gas and stores the heat, and low-temperature fluid to be heated such as combustion air is heated by the heat stored in the heat storage body; and a sector plate for dividing the flow passages for the abovementioned two kinds of fluids, namely the heating fluid and the fluid to be heated, flowing through the inside of the rotor is provided at the upper end face of the rotor with a slight gap therebetween, and a static seal is disposed on both sides of the gap between the sector plate and the external structure of the heat exchanger, a suction pipe being provided in the external structure in such a way as to suction dust material such as ash which accumulates or is agitated on the sector plate.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Patent Application No. 2011-281662, filed on Dec. 22, 2011, which is incorporated herein by reference in its entirety

TECHNICAL FIELD

The present invention relates to a rotary regenerative heat exchanger.

PRIOR ART

A rotary regenerative heat exchanger which is generally installed as an air preheater in a power generation plant or the like conventionally has a structure in which a rotor 1 accommodating a heat storage body 1a such as a heat transfer element is rotated inside a housing 2, the heat storage body 1a is heated by means of a high-temperature heating fluid G1 such as exhaust gas and stores the heat, and low-temperature fluid to be heated G2 such as combustion air is heated by the heat stored in the heat storage body 1a, as shown in FIG. 3.

As is clear from FIG. 4, the flow passages for the abovementioned two kinds of fluids, namely G1 and G2, which flow through the inside of the rotor 1 are divided by means of sector plates 3, 3′ which are provided at the upper and lower end faces of the rotor 1 with a slight gap therebetween.

Two leaks (leakages) are produced in a rotary regenerative heat exchanger of this type, from the side of the fluid to be heated G2, which is the high-pressure side, toward the heating fluid G1 side, which is the low-pressure side. The first leak is a direct leak caused by the difference in pressure between the two fluids G1, G2, and the second leak is an entrained leak accompanying rotation of the rotor 1.

Sealing mechanisms are normally provided in various locations of the heat exchanger in order to prevent direct leaks, and a radial sealing part on the high-temperature side which is one such mechanism comprises the sector plates 3, 3′, constituting the fixed side, and a radial seal 1b which is fitted to the rotor 1, constituting the rotating side. In particular, the upper sector plate 3 is connected to an upper external structure 2′ by way of adjuster rod 4, and a static seal 5 is disposed on both sides of the gap between the sector plate 3 and the external structure of the heat exchanger in order to prevent direct leaks from the gap S between the external structure 2′ and the upper face of the sector plate 3.

There is also a system in which static seals 5, 5 are disposed on both sides of the sector plate 3, as shown in FIG. 5, thereby providing an intermediate pressure zone, in order to enhance the sealing effect at the upper part of the sector plate 3. Furthermore, the static seals 5 consist of metal sheets.

SUMMARY OF THE INVENTION

Problem to be Resolved by the Invention

However, if the static seals 5, 5 are provided on both sides of the sector plate 3, as described above, ash etc. accompanying entrained leaks from the heating fluid G1 side accumulates on the upper face of the sector plate 3 as a deposit T, as shown in FIG. 6, and therefore the movement of the sector plate 3 is impeded and there is a risk that the rotary regenerative heat exchanger will cease operating.

Furthermore, in the case of the sector plate 3 comprising the abovementioned metal sheets, a very small gap at the seal part is inevitable, as shown in FIG. 7, and the performance of the rotary regenerative heat exchanger is degraded by leak flows produced from this gap, while at the same time there is a risk of erosion caused by ash contained in the leak flow.

The present invention is intended to resolve the abovementioned conventional problems, and the issue addressed by the present invention lies in providing a rotary regenerative heat exchanger which makes it possible to enhance the sealing effect and to prevent erosion, without any risk at all of deposits accumulating on the sector plate, and without inviting any impediment to operation of the rotary regenerative heat exchanger.

Means for Resolving the Problem

The rotary regenerative heat exchanger according to the present invention has a structure in which a rotor accommodating a heat storage body such as a heat transfer element is rotated inside a housing, the heat storage body is heated by means of a high-temperature heating fluid such as exhaust gas and stores the heat, and low-temperature fluid to be heated such as combustion air is heated by the heat stored in the heat storage body; and a sector plate for dividing the flow passages for the abovementioned two kinds of fluids, namely the heating fluid and the fluid to be heated, flowing through the inside of the rotor, is provided at the upper end face of the rotor with a slight gap therebetween, and a static seal is disposed on both sides of the gap between the sector plate and the external structure of the heat exchanger, said rotary regenerative heat exchanger being characterized in that a suction pipe is provided in the external structure in such a way as to suction dust material such as ash which has accumulated or been agitated on the sector plate.

Advantages of the Invention

The rotary regenerative heat exchanger according to the present invention demonstrates the following advantages.

• • 1) A construction is adopted such that dust material such as ash which intrudes onto the sector plate is removed at any time by a blowing pipe or the suction pipe, so movement of the sector plate is no longer impeded by the accumulation of dust material and there is no risk that the rotary regenerative heat exchanger will cease operating.
  • 2) The fabric cloth material is attached in such a way as to be joined along the region of the outer face at the tip end of the static seal, so the seal effect is enhanced, dust material such as ash does not intrude onto the sector plate, and there is no risk of erosion.
  • 3) The fabric cloth material is attached in a slackened state so it can follow the vertical movement of the sector plate.
  • 4) The fabric cloth material can be easily replaced with the aid of attachment members 8a and 8b.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a main part structural illustration showing one exemplary embodiment of the present invention;

FIG. 2 is a main part structural illustration showing a different exemplary embodiment of the present invention;

FIG. 3 is an overall oblique view of a rotary regenerative heat exchanger;

FIG. 4 (A) is a schematic diagram in plan view of the main parts of a conventional rotary regenerative heat exchanger and (B) is a view in cross section along the line a-a in (A);

FIG. 5 illustrates the sealing structure at the upper part of the sector plate in a conventional rotary regenerative heat exchanger;

FIG. 6 illustrates the problem with the sealing structure in FIG. 5; and

FIG. 7 illustrates a different sealing structure at the upper part of the sector plate in a conventional rotary regenerative heat exchanger.

MODE OF EMBODIMENT OF THE INVENTION

Exemplary embodiments of the rotary regenerative heat exchanger according to the present invention will be described below with reference to the figures.

In FIG. 1, 2′ is an external structure, 3 is a sector plate and 5 is a static seal. 6 are blowing pipes and 7 is a suction pipe.

The blowing pipes 6 are provided in the external structure 2′ and are connected to a suitable blowing device (not depicted). The blowing pipes 6 jet compressed air fed from the blowing device toward the upper face of the sector plate 3 in order to agitate dust material such as ash which has accumulated.

The suction pipe 7 is provided in the external structure 2′ and is connected to a suitable suction device (not depicted). The suction pipe 7 suctions dust material such as ash which has been agitated or accumulated, by means of the suction action afforded by the suction device.

In FIG. 1, two blowing pipes 6 are provided with a suitable gap therebetween in the widthwise direction of the sector plate 3, and one suction pipe 7 is provided between the blowing pipes 6, but the number and arrangement of the blowing pipes 6 and suction pipe 7 are not limited by the above, and the pipes may be suitably disposed in the lengthwise direction of the sector plate 3 or in any arrangement provided that dust material can be efficiently suctioned. Furthermore, the jetting and suction actions afforded by the blowing pipes 6 and suction pipe 7 may be produced by either continuous operation or discontinuous (intermittent) operation. In addition, only the suction pipe 7 may be operated, and the blowing pipes 6 operated when needed. The blowing pipes 6 may be absent, depending on the case.

The rotary regenerative heat exchanger according to this exemplary embodiment is constructed in such a way that dust material such as ash which has intruded onto the sector plate 3 is removed at any time by means of the blowing pipes 6 and suction pipe 7, or by means of the suction pipe 7 alone, and therefore movement of the sector plate 3 is no longer impeded by the accumulation of dust material and there is no risk that the rotary regenerative heat exchanger will cease operating.

FIG. 2 shows a different exemplary embodiment of the present invention, where 2′ is the external structure, 3 is the sector plate and 5 is the static seal.

8 is a fabric cloth material which is joined along the region of the outer face at the tip end of the static seal 5. One end of the fabric cloth material is fixed to the static seal 5 by means of an attachment member 8a while the other end is fixed to the sector plate 3 by means of an attachment member 8b.

Any material may be used for the fabric cloth material 8 provided that it is a very flexible fabric which has a filter function with respect to dust material such as ash. The fabric cloth material 8 is attached in a slackened state so that it can follow the vertical movement of the sector plate 3. Furthermore, the fabric cloth material 8 is detachably attached by means of the attachment members 8a and 8b so that it can be easily replaced.

The rotary regenerative heat exchanger according to this exemplary embodiment is constructed in such a way that the fabric cloth material is joined along the region of the outer face at the tip end of the static seal 5, and therefore the seal effect is enhanced, dust material such as ash does not intrude onto the sector plate 3, and there is no risk of erosion.

Claims

1. A rotary regenerative heat exchanger comprising:

a rotatable rotor accommodating a heat storage body inside a housing, wherein the heat storage body is heated by means of a high-temperature heating fluid for storage of heat by the heat storage body;

a low-temperature fluid heated by the heat stored in the heat storage body;

a sector plate dividing a high-temperature heating fluid flow passage from a low-temperature fluid flow passage, with each passage arranged through an inside of the rotor with a gap therebetween,

a static seal disposed on sides of the gap between the sector plate and the housing of the heat exchanger, and

a suction pipe arranged in the housing to remove by suction a dust material accumulated on or agitated from the sector plate.

2. The rotary regenerative heat exchanger according to claim 1, further comprising a blowing pipe arranged in the housing supplying compressed air jetted toward an upper face of the sector plate to agitate dust material therefrom.

3. A rotary regenerative heat exchanger comprising:

a housing in which a rotor accommodating a heat storage body is rotated inside, with the heat storage body heated by means of a high-temperature heating fluid for heat storage therein;

a low-temperature fluid heated by the heat stored in the heat storage body;

a sector plate dividing separate flow passages for each the high-temperature heating fluid and the low-temperature fluid to flow through an inside of the rotor with a slight gap between flow passages,

a static seal disposed on sides of the gap between the sector plate and the housing;

a fabric cloth material is attached with one end thereof fixed to the static seal by means of a first attachment member while another end is fixed to the sector plate by means of a second attachment member.

4. The rotary regenerative heat exchanger according to claim 3, wherein the fabric cloth material is slackened when fixed by the first and second attachment members.

5. The rotary regenerative heat exchanger according to claim 3, wherein the fabric cloth material is removably fixed by the first and second attachment members.