Information
-
Patent Grant
-
6405789
-
Patent Number
6,405,789
-
Date Filed
Thursday, May 10, 200123 years ago
-
Date Issued
Tuesday, June 18, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Bennett; Henry
- McKinnon; Terrell
Agents
-
CPC
-
US Classifications
Field of Search
US
- 165 8
- 165 9
- 165 10
- 165 72
- 165 73
- 165 77
-
International Classifications
-
Abstract
A combined door and platform assembly for an air preheater having a housing with an access opening. The assembly includes a door frame which is fixedly mounted to the outer surface of the housing around the access opening. The bottom portion of a base is permanently, pivotally mounted to the door frame. The base is moveable from a vertical position, where the base acts as a door closing the access opening, to a horizontal position, where the base acts as a platform to facilitate removal and replacement of basketed materials disposed within the housing.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to rotary heat exchangers and, more specifically, to an integrated means for removing and replacing basketed material within duct work or an air preheater rotor.
A rotary regenerative heat exchanger is employed to transfer heat from one hot gas stream, such as a flue gas stream, to another cold gas stream, such as combustion air. The rotor contains a mass of heat absorbent material which is first positioned in a passageway for the hot gas stream where heat is absorbed by the heat absorbent material. As the rotor turns, the heated absorbent material enters the passageway for the cold gas stream where the heat is transferred from the absorbent material to the cold gas stream.
In a typical rotary heat exchanger, such as a rotary regenerative air preheater, the cylindrical rotor is disposed on a central rotor post and divided into a plurality of sector-shaped compartments by a plurality of radial partitions, known as diaphragms, extending from the rotor post to the outer peripheral shell of the rotor. These sector shaped compartments are loaded with modular heat exchange baskets which contain the mass of heat absorbent material commonly comprised of stacked plate-like elements.
Conventional heat exchange baskets may be loaded axially into the rotor from the top end (duct end) or radially through the side of the rotor. Both designs require the positioning of the heavy, bulky heat exchange baskets. The conventional method for removing and replacing radially loaded heat exchange baskets is time consuming and requires the following:
1) The basket removal door is removed and stored.
2) A platform is retrieved from storage and mounted to a pair of columns positioned on either side of the basket removal door opening in the air preheater housing.
3) The heat exchange baskets are pulled from the air preheater onto the platform, lifted off of the platform, and removed from the area.
4) New baskets are placed on the platform and slid into the rotor.
5) The platform is removed and stored in a remote location.
6) The basket removal door is retrieved from storage and reinstalled.
Although the conventional basket installation/removal platform is functionally a good design, it is large and heavy, requiring a crane for installation and removal. Since the heat transfer matrix in the air preheater is long lasting (in many cases having a lifetime of over 5 years) the platform is not a commonly used maintenance item and generally must be stored away from the air preheater. The size and weight of the platform makes transporting the platform to and from storage a difficult task. In addition, the basket removal door must be completely removed and stored during the basket installation/removal process.
SUMMARY OF THE INVENTION
The present invention relates to a combined door and platform assembly for an air preheater having a housing with an access opening. The assembly includes a door frame which is fixedly mounted to the outer surface of the housing around the access opening. The bottom portion of a base is permanently, pivotally mounted to the door frame. The base is moveable from a vertical position, where the base acts as a door closing the access opening, to a horizontal position, where the base acts as a platform to facilitate removal and replacement of basketed materials disposed within the housing.
A pair of side safety panels are pivotally mounted to the sides of the base and an end safety panel is pivotally mounted to the free end of the base. Each of the safety panels is moveable between an extended position, where the safety panel extends substantially perpendicularly from the base, and a storage position, where the safety panel is disposed adjacent the base. The assembly includes stops preventing movement of the safety panels past the extended position and locks selectively holding the safety panels in the extended position. Each safety panel includes multiple posts, at least one hand rail mounted to the posts, and a kick board mounted to the bottom end portions of the posts. The kick board or the bottom end portions of the posts are pivotally mounted to the base.
Preferably, a pair of braces connect the side edges of the base to the side members of the door frame and thereby provide additional mechanical support to the base. Apparatus is provided to lock the base in the vertical position during operation of the air preheater.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a general perspective view of a rotary regenerative air preheater.
FIG. 2
is a schematic perspective view of an air preheater housing having a conventional basket access door and a conventional platform.
FIG. 3
is a top view of the air preheater housing, conventional basket access door, and conventional platform of FIG.
2
.
FIG. 4
is a side view of the air preheater housing, conventional basket access door and conventional platform of FIG.
2
.
FIG. 5
is a schematic perspective view of an air preheater housing and a combined basket access door and platform in accordance with the invention.
FIG. 6
is a top view of the air preheater housing and combined basket access door and platform of FIG.
5
.
FIG. 7
is a side view of the air preheater housing and combined basket access door and platform of FIG.
5
.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
of the drawings is a partially cut-away perspective view of a typical air preheater
10
showing a housing
12
in which the rotor
14
is mounted on drive shaft or post
16
for rotation as indicated by the arrow
18
. The rotor is composed of a plurality of sectors
20
with each sector containing a number of heat exchange baskets
22
and with each sector being defined by the diaphragms
24
. The heat exchange baskets
22
contain the heat exchange surface. The housing
12
is divided by means of the flow impervious sector plate
26
into a flue gas side and an air side. A corresponding sector plate is also located on the bottom of the unit. The hot flue gases enter the air heater through the gas inlet duct
28
, flow through the rotor where heat is transferred to the rotor and then exit through gas outlet duct
30
. The countercurrent flowing air enters through air inlet duct
32
, flows through the rotor where it picks up heat and then exits through air outlet duct
34
.
FIGS. 2
,
3
, and
4
illustrate a conventional basket access door
36
and conventional platform
38
mounted to the housing
12
of an air preheater
10
. The conventional basket access door
36
is removably mounted to a door frame
40
which is permanently affixed to the outer surface
42
of the housing
12
around a basket access opening
44
. First and second columns
46
,
48
are vertically mounted on either side of the door frame
40
.
The conventional basket removal platform
38
includes a platform base
50
, safety hand rails
52
, and safety posts
54
mounting the hand rails
52
to the platform base
50
. The door
36
is dismounted from the door frame
40
and put into storage for the duration of the basket transfer procedure. The basket removal platform
38
is retrieved from storage and mounted to the air preheater housing
12
by temporarily mounting the inner platform safety posts
54
and the platform base
50
to the columns
46
,
48
. A pair of support bars
56
mounted to platform base
50
and the columns
46
,
48
provide additional support to the platform base
50
.
The combined basket access door and platform comprises a platform/door assembly
60
which is permanently mounted to the air preheater housing
12
, eliminating the basket access door removal, storage, retrieval, and reinstallation tasks and the basket removal platform retrieval, installation, removal, and storage tasks that are conventionally required to allow the transfer of heat exchange baskets
22
. The platform/door assembly
60
includes a door frame
62
which is permanently mounted to the outer surface
42
of the housing
12
around the basket access opening
44
. Pivot pins
64
fixedly mounted to the bottom portion
66
of the oppositely disposed outside edges
68
of the platform/door base
70
are received in openings
72
in the lower end portions
74
of each side member
76
of the door frame
62
to pivotally mount the bottom portion
66
of the platform/door base
70
to the door frame
62
.
During normal operation, openings
78
in the side members
76
of the door frame
62
and the outside edges
68
of the platform/door base
70
receive bolts (not shown) to secure the platform/door base
70
in a first, vertical position, where the platform/door base
70
acts as a door to close the basket access opening
44
. The platform/door base
70
may be unbolted from the frame
62
and pivotally moved to a second, horizontal position, where the platform/door base
70
acts as a basket removal platform. Upper and lower end portions
80
,
82
of a pair of diagonal braces
84
are mounted to the side members
76
of the door frame
62
and the outside edges
68
of the platform/door base
70
, respectively, to provide additional support to the platform/door base
70
.
A pair of side safety panels
86
and at least one end safety panel
88
fold up to form safety hand rails during basket transfer operations and fold down for storage, allowing the platform/door base
70
to be moved to the vertical position. Each safety panel
86
,
88
includes an upper hand rail
90
, an intermediate hand rail
92
, and a kick board
94
which are mounted to two or more posts
96
. The kick board
94
and/or the bottom end portions
98
of the posts
96
are pivotally mounted to the platform/door base
70
. Each safety panel
86
,
88
is pivotally moveable from an extended position, where the safety panel
86
,
88
extends substantially perpendicularly from the platform/door base
70
, to a storage position, where the safety panel
86
,
88
is disposed adjacent the inner surface
100
of the platform/door base
70
.
Preferably, the platform/door assembly
60
includes apparatus for limiting the pivotal movement of each safety panel
86
,
88
such that the safety panels
86
,
88
may not be pivoted past the extended position. For example, the platform/door base
70
may include an upwardly extending lip which engages the kick board
94
and/or the bottom end portions
98
of the posts
96
when the safety panel
86
,
88
is in the extended position. The platform/door assembly
60
also preferably includes apparatus for locking each safety panel
86
,
88
in both the extended position and the storage position. For example, spring-loaded detents mounted to one of the safety panel
86
,
88
or platform/door base
70
may be received in an aperture in the other of the platform/door base
70
or safety panel
86
,
88
when the safety panel
86
,
88
is in either position.
The combined basket access door and platform is a unique solution for the installation and removal of heat exchange baskets
22
from the air preheater
10
. The combined basket access door and platform eliminates the need for storage space for the platform while continuing to provide the same functionality of the externally mounted platform design.
Claims
- 1. A door and platform assembly for an air preheater including a housing having an outer surface and an access opening, the assembly comprising:a door frame adapted for fixedly mounting to the outer surface of the housing surrounding the access opening; a base having oppositely disposed first and second sides and oppositely disposed first and second ends, the first end being permanently, pivotally mounted to the door frame, the base being moveable between a closed position, wherein the base defines a door closing the access opening, and an open position, wherein the base defines a platform extending horizontally from the door frame to the second end; and first and second side safety panels pivotally mounted to the first and second sides of the base, respectively, and an end safety panel pivotally mounted to the second end of the base, each of the safety panels being moveable between an extended position, wherein the safety panel extends substantially perpendicularly from the base, and a storage position, wherein the safety panel is disposed adjacent the base.
- 2. The assembly of claim 1 wherein each safety panel includes a stop preventing movement of the safety panel past the extended position.
- 3. The assembly of claim 1 wherein each safety panel includes a lock selectively holding the safety panel in the extended position.
- 4. A door and platform assembly for removal and replacement of basketed materials from an air preheater including a housing having an outer surface and a basket access opening, the assembly comprising:a door frame adapted for fixedly mounting to the outer surface of the housing around the basket access opening; a base permanently mounted to the door frame, the base having a periphery and being pivotally moveable between a closed position, wherein the base defines a door closing the basket access opening, and an open position, wherein the base defines a platform; and a plurality of safety panels mounted to the base adjacent to the periphery of the base, each of the safety panels being pivotally moveable between an extended position, wherein the safety panel extends substantially perpendicularly from the base, and a storage position, wherein the safety panel is disposed adjacent the base.
- 5. The assembly of claim 4 wherein each safety panel includes a plurality of posts, at least one hand rail, and a kick board, each of the posts having a bottom end portion, the hand rail being mounted to the posts, and the kick board being mounted to the bottom end portions of the posts, the kick board or the bottom end portions of the posts being pivotally mounted to the base.
- 6. The assembly of claim 4 wherein each safety panel includes a stop preventing movement of the safety panel past the extended position and a lock selectively holding the safety panel in the extended position.
- 7. The assembly of claim 4 further comprising at least one brace connecting the base to the door frame and supporting the base thereon.
- 8. A combined door and platform assembly for removal and replacement of basketed materials from an air preheater including a housing having an outer surface and a basket access opening, the assembly comprising:a door frame adapted for fixedly mounting to the outer surface of the housing around the basket access opening; and a base having a bottom portion permanently pivotally mounted to the door frame, the base being pivotally moveable from a vertical position, wherein the base defines a door closing the basket access opening, to a horizontal position, wherein the base defines a platform.
- 9. The assembly of claim 8 wherein the base also has first and second, oppositely disposed side edges and the door frame includes first and second, oppositely disposed side members, each of the side members having a lower end portion, first and second side edges of the base being pivotally mounted to the lower end portions of the first and second side members of the door frame, respectively.
- 10. The assembly of claim 9 wherein the lower end portions of each side member of the door frame defines an opening and the base further has first and second pivot pins mounted to the first and second side edges, respectively, at the bottom portion of the base, the first and second pivot pins being received in the openings of the first and second side members, respectively, to pivotally mount the base to the door frame.
- 11. The assembly of claim 8 further comprising means for securing the base in the vertical position.
- 12. The assembly of claim 8 further comprising first and second braces, the base also having first and second, oppositely disposed side edges and the door frame including first and second, oppositely disposed side members, the first and second braces being mounted to the first and second side members of the door frame and the first and second side edges of the base.
- 13. The assembly of claim 8 further comprising at least one safety panel, each safety panel having a lower end portion pivotally mounted to the base and being pivotally moveable between an extended position, wherein the safety panel extends substantially perpendicularly from the base, to a storage position, wherein the safety panel is disposed adjacent the base.
- 14. The assembly of claim 13 wherein each safety panel includes a plurality of posts and at least one hand rail mounted to the posts.
- 15. The assembly of claim 14 wherein each post has a bottom end portion and each safety panel also includes a kick board mounted to the bottom end portions of the posts, the kick board or the bottom end portions of the posts being pivotally mounted to the base.
- 16. The assembly of claim 13 further comprising means for limiting pivotal movement of each safety panel whereby the safety panel may not be pivoted past the extended position.
- 17. The assembly of claim 16 wherein the base also has an orthogonally extending lip defining the means for limiting pivotal movement, the lip engaging the safety panel when the safety panel is in the extended position.
- 18. The assembly of claim 13 further comprising means for locking each safety panel in the extended position.
US Referenced Citations (8)