U.S. patent application number 11/770904 was filed with the patent office on 2009-01-01 for brush-seal and matrix for regenerative heat exchanger, and method of adjusting same.
This patent application is currently assigned to WILSON TURBOPOWER, INC.. Invention is credited to Jon M. Ballou, Kelly Ward, David Gordon Wilson.
Application Number | 20090000762 11/770904 |
Document ID | / |
Family ID | 40158990 |
Filed Date | 2009-01-01 |
United States Patent
Application |
20090000762 |
Kind Code |
A1 |
Wilson; David Gordon ; et
al. |
January 1, 2009 |
BRUSH-SEAL AND MATRIX FOR REGENERATIVE HEAT EXCHANGER, AND METHOD
OF ADJUSTING SAME
Abstract
Disclosed is a regenerative heat exchanger including a
brush-seal configuration to prevent mixing of fluid flows. The
regenerative heat exchanger includes a regenerator, and at least
two conduits, each conduit having a matrix end abutting a face of
the regenerator matrix. The at least two conduits carrying at least
two fluid flows, the fluid flows which pass through the regenerator
matrix. The regenerative heat exchanger includes a plurality of
brush-seals, each brush-seal located at a matrix end of each
conduit without contacting the matrix, thereby sealing around a
periphery of each conduit to prevent mixing of fluid flows. Also
disclosed is a method for establishing a minimal gap between a
regenerator matrix of a regenerative heat exchanger and a plurality
of brush-seals.
Inventors: |
Wilson; David Gordon;
(Winchester, MA) ; Ballou; Jon M.; (Beverly,
MA) ; Ward; Kelly; (Peabody, MA) |
Correspondence
Address: |
CANTOR COLBURN, LLP
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
WILSON TURBOPOWER, INC.
Woburn
MA
|
Family ID: |
40158990 |
Appl. No.: |
11/770904 |
Filed: |
June 29, 2007 |
Current U.S.
Class: |
165/9 |
Current CPC
Class: |
F23L 15/02 20130101;
Y02E 20/34 20130101; Y02E 20/348 20130101; F28D 19/047
20130101 |
Class at
Publication: |
165/9 |
International
Class: |
F23L 15/02 20060101
F23L015/02 |
Claims
1. A regenerative heat exchanger comprising: a regenerator matrix;
at least two conduits, each conduit having a matrix end abutting a
face of the regenerator matrix, the at least two conduits carrying
at least two fluid flows, the fluid flows passing through the
regenerator matrix; and a plurality of brush-seals, each brush-seal
disposed at a matrix end of each conduit without contacting the
matrix, thereby sealing around a periphery of each conduit to
prevent mixing of fluid flows.
2. The regenerative heat exchanger of claim 1 wherein each
brush-seal is affixed to a casing.
3. The regenerative heat exchanger of claim 2 wherein the plurality
of brush-seals is affixed to the casing by a plurality of
screws.
4. The regenerative heat exchanger of claim 3 wherein each screw is
installed through a slotted hole in the casing, allowing the
position of the brush-seal to be adjusted.
5. The regenerative heat exchanger of claim 2 wherein the plurality
of brush-seals is affixed to the casing by adhesive.
6. The regenerative heat exchanger of claim 1 wherein the
regenerator matrix includes a plurality of axially-oriented
internal passageways.
7. The regenerative heat exchanger of claim 1 wherein the
regenerator matrix is formed of a low-thermal-conductivity and
high--heat-capacity material.
8. The regenerative heat exchanger of claim 7 wherein the
regenerator matrix is formed from a ceramic material.
9. The regenerative heat exchanger of claim 1 wherein the
regenerator matrix includes an abradable coating layer.
10. The regenerative heat exchanger of claim 1 wherein each
brush-seal is formed from a superalloy material.
11. The regenerative heat exchanger of claim 1 wherein each
brush-seal is formed from a ceramic material.
12. A method for establishing a minimal gap between a regenerator
matrix of a regenerative heat exchanger and a plurality of
brush-seals, the brush-seals sealing around a periphery of each
conduit of a plurality of conduits carrying fluid flows which pass
thorough the regenerator matrix, the method comprising: installing
the plurality of brush-seals such that a bristle end of each
brush-seal contacts a face of the regenerator matrix; rotating the
regenerator matrix at a desired speed about an axis substantially
perpendicular to the face of the regenerator matrix, friction
between the bristle end and the face causing material to be removed
from the bristle end and/or the face of the regenerator matrix;
stopping rotation of the regenerator matrix when a power required
to rotate the regenerator matrix at the desired speed reaches a
predetermined level, stopping the removal of material from the
bristle end and/or the face of the regenerator matrix and
establishing a minimal gap between the bristle end and the face of
the regenerator matrix.
13. The method of claim 9 wherein the face of the regenerator
matrix includes an abradable coating layer.
14. The method of claim 9 wherein the temperatures of the flows
passing through the regenerator are substantially the same as at
normal operation of the regenerative heat exchanger.
15. The method of claim 9 wherein the power is continuously
monitored to determine when the power reaches the predetermined
level.
16. The regenerative heat exchanger of claim 9 wherein the
regenerator matrix is formed from a ceramic material.
17. The regenerative heat exchanger of claim 9 wherein each
brush-seal is formed from a superalloy material.
18. The regenerative heat exchanger of claim 9 wherein each
brush-seal is formed from a ceramic material.
Description
BACKGROUND OF THE INVENTION
[0001] This invention generally relates to heat exchangers. In
particular, the present invention relates to seals for rotary
regenerative heat exchangers.
[0002] A regenerative heat exchanger (regenerator) uses a heat
transfer matrix which is rotated through a hot and a cold stream
consecutively to transfer heat from the former to the latter. The
device call also be used to transfer mass between two fluids
differing in concentration in a targeted constituent and the
exchange (be it mass and/or heat) can involve any number of flows
greater than one.
[0003] Each of the hot and cold flows is typically carried to and
from the matrix by a conduit. The flows enter and exit the matrix
through a face of the matrix, and a configuration of seals is
located between the conduits and the rotating matrix face to
prevent leakage of the flows from the conduits into the environment
or from one flow into another. Two types of seals are generally
used, non-contact seals or contact seals. With non-contact seals
(which do not contact the matrix face), it is a major challenge to
properly adjust a gap between the matrix face and the non-contact
seal minimizing leakage to maximize efficiency of the heat
exchanger. Contact seals (which do contact the matrix face) ensure
lower leakage which improves efficiency of the regenerator as
compared to non-contact seals. Use of contact seals, however,
causes increased seal wear and also reduces efficiency of the
regenerator due to the increased function between the contact seal
and the matrix that must be overcome in the rotation of the matrix.
Additionally, rubbing of the contact seals on the regenerator
matrix can over time produce solid material (either from the matrix
or the seals) which will contaminate the flow and might lead to
clogging in a porous matrix.
BRIEF DESCRIPTION OF THE INVENTION
[0004] The present invention solves the aforementioned problems by
providing a regenerative heat exchanger including a brush-seal
configuration to prevent mixing of fluid flows. The regenerative
heat exchanger includes a regenerator matrix, and at least two
conduits, each conduit having a matrix end abutting a face of the
regenerator matrix. At least two conduits carry at least two fluid
flows which pass through the regenerator matrix. The regenerative
heat exchanger includes a plurality of brush-seals. Each brush-seal
is located at a matrix end of each conduit without contacting the
matrix, thereby sealing around a periphery of each conduit to
prevent mixing of fluid flows.
[0005] A method for establishing a minimal gap between a
regenerator matrix of a regenerative heat exchanger and a plurality
of brush-seals is disclosed. The method includes installing the
plurality of brush-seals such that a bristle end of each brush-seal
contacts a face of the regenerator matrix. The regenerator matrix
is rotated at a desired speed about an axis substantially
perpendicular to the face of the regenerator matrix. During
rotation, friction between the bristle end and the face causes
material to be removed from the bristle end. The rotation is
stopped when a power required to rotate the regenerator matrix at
the desired speed reaches a predetermined level. This stops the
removal of material from the bristle end and establishes a minimal
gap between the bristle end and the face of the regenerator
matrix.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The above, as well as other advantages of the present
invention, will become readily apparent to those skilled in the art
from the following detailed description of preferred embodiments
when considered in light of the accompanying drawings in which:
[0007] FIG. 1 depicts an end view of an embodiment of a
regenerative heat exchanger;
[0008] FIG. 2 depicts a cross-sectional view of the regenerative
heat exchanger of FIG. 1; and
[0009] FIG. 3 depicts an enlarged view of the circled portion of
FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The detailed description explains embodiments of the
invention, together with advantages and features, by way of example
with reference to the drawings.
[0011] Shown in FIG. 1 is an embodiment of a regenerative heat
exchanger (regenerator) 10. Referring now to FIG. 2, the
regenerator 10 includes a regenerator matrix 12. The matrix 12
generally comprises a body having a plurality of internal
passageways (not shown) oriented in all axial direction, and may be
formed of a low-thermal-conductivity and high-heat-capacity
material, for example, a ceramic material. In some embodiments, the
matrix 12 may include an abradable coating layer (not shown) to
protect the matrix 12 material from wear. The matrix 12 in some
embodiments is cylindrical in shape, but other shapes are
contemplated within the scope of this invention. The matrix 12 is
disposed across two or more fluid streams. Each fluid stream is
carried in a conduit. In this embodiment, a cold fluid stream is
carried in a first conduit 14 and a hot fluid stream is carried in
a second conduit 16.
[0012] The matrix 12 is connected to a drive motor 18. The drive
motor 18 causes the matrix 12 to rotate about a matrix axis 20 and
transfer heat from the hot fluid stream carried through second
conduit 16 to the cold fluid stream carried through first conduit
14. Because the matrix 12 moves relative to the first conduit 14
and the second conduit 16, a configuration of seals is required on
a face 22 of the matrix 12 to prevent leakage, including leakage
from the conduits 14 or 16, and leakage between the first conduit
14 and the second conduit 16.
[0013] Sealing between the face 22 and each of the conduits 14 and
16 is accomplished by a brush-seal configuration 24. The brush-seal
configuration 24 between first conduit 14 and the face 22 is
substantially identical to the brush-seal configuration 24 between
second conduit 16 and the face 22, so only the brush-seal
configuration 24 between first conduit 14 and the face 22 will be
described herein. The brush-seal configuration 24 may be made from
a variety of materials including metal, super alloys, ceramics,
etc., and is chosen depending on thermal and chemical requirements
of the application. As shown in FIG. 3, the brush-seal 24 extends
around a periphery of the first conduit 14 at the face 22, and is
fixed to a seal holder 26 at a base end 28 of the brush-seal 24 by
a plurality of seal screws 30 or other means. In this example, the
seal holder 26 has a U-shaped section 32 for receiving brush-seal
24. A seal screw 30 is inserted though a screw hole (not shown) in
the section 32 and threaded into a seal hole (not shown) securing
the blush-seal 24 to the seal holder 26.
[0014] The seal holder 26 is secured to a casing 34 by a plurality
of casing screws 36. The casing 34 extends circumferentially around
the first conduit 14, and is fixed relative to the first conduit
14. The casing screws 36 are inserted in a radial direction through
axially-slotted holes 38 in the seal holder 26 and into threaded
casing holes (not shown) in the casing 34, thereby securing the
seal holder 26 to the casing 34. The slotted holes 38 allow the
position of the seal holder 26 to be adjusted relative to the
casing 34, and thus the position of the brush-seal 24 relative to
the face 22 can be adjusted. Initially, the brush-seal 24 is
positioned so the bristles 40 are in contact with the face 22. It
is to be appreciated that the attachment scheme of the blush-seals
24 described herein is only an example. Other attachment schemes
including, for example, adhesive attachment, are contemplated
within the scope of this invention.
[0015] When the blush-seals 24 are installed, a break-in process is
employed to establish a minimal gap between the blush-seals 24 and
the matrix 12 at the faces 22. In one embodiment, a necessary
power, P.sub.ref, for rotation of the matrix 12 at a desired
rotation speed is determined prior to installing the brush-seals
24. The brush-seals 24 are installed so the bristles 40 contact the
matrix 12 as described above. The matrix 12 is rotated to the
desired rotation speed, and a power required to rotate the matrix
12, P.sub.in, is monitored. Initially, because of the contact
between the bristles 40 and the matrix 12, P.sub.in>P.sub.ref.
During this break-in process, the regenerator 10 is run under
normal wordings conditions, i.e. the flows passing through the
regenerator will be at the temperatures of the flows during normal
operation. The friction between the bristles 40 and the matrix 12
during the break-in process increases the temperature of the
bristles 40 and the matrix 12, and thus will cause slightly
increased thermal expansion of the matrix 12 and the bristles 40
over that which would occur during normal operation.
[0016] As the break-in process progresses, material is worn off of
the bristles 40 and/or the face 22. As material is worn off,
friction between the bristles 40 and the matrix 12 is reduced.
Because of the reduced friction, the temperature of bristles 40 and
the matrix 12 are reduced slightly, reducing thermal expansion of
the bristles 40 and the matrix 12, thus creating a slight gap
between the bristles 40 and the matrix 12. The reduced friction
also reduces P.sub.in required for the matrix 12 to rotate at the
desired speed. P.sub.in is monitored until P.sub.in=P.sub.ref, at
which point the break-in process is completed, leaving the desired
gap between the bristles 40 and the matrix 12.
[0017] While embodiments of the invention have been described
above, it will be understood that those skilled in the art, both
now and in the future, may make various improvements and
enhancements which fall within the scope of the claims which
follow. These claims should be construed to maintain the proper
protection for the invention first described.
* * * * *