U.S. patent application number 12/790133 was filed with the patent office on 2011-03-03 for method for the temperature-dependent setting of a sealing gap in a regenerative heat exchange, and the respective actuating apparatus.
This patent application is currently assigned to Balcke-Durr GmbH. Invention is credited to Volker Halbe, Miroslav Podhorsky, Heinz-Guenter Raths.
Application Number | 20110048670 12/790133 |
Document ID | / |
Family ID | 41258955 |
Filed Date | 2011-03-03 |
United States Patent
Application |
20110048670 |
Kind Code |
A1 |
Podhorsky; Miroslav ; et
al. |
March 3, 2011 |
METHOD FOR THE TEMPERATURE-DEPENDENT SETTING OF A SEALING GAP IN A
REGENERATIVE HEAT EXCHANGE, AND THE RESPECTIVE ACTUATING
APPARATUS
Abstract
The invention relates to a method for temperature-dependent
setting of a sealing gap between an adjustable seal and a revolving
rotor of a regenerative heat exchanger by means of at least one
actuating apparatus which comprises at least one rod body which is
thermally influenced in an alternating manner and whose
temperature-dependent change in axial length is converted into an
actuating movement for the seal. It is provided in accordance with
the invention that this rod bod is arranged at least in sections in
a chamber and a control medium flows through or about this chamber
at least in part, which medium acts in a direct or indirect manner
in a thermally alternating fashion on said rod body, with the
temperature level of the control medium corresponding to a
temperature level of a gas volume flow flowing through the rotor,
so that a change in axial length of this rod body is produced
depending on a temperature change of this gas volume flow and a
respective actuating movement for the seal is brought about.
Inventors: |
Podhorsky; Miroslav;
(Ratingen, DE) ; Halbe; Volker; (Olpe, DE)
; Raths; Heinz-Guenter; (Olpe, DE) |
Assignee: |
Balcke-Durr GmbH
Ratingen
DE
|
Family ID: |
41258955 |
Appl. No.: |
12/790133 |
Filed: |
May 28, 2010 |
Current U.S.
Class: |
165/4 |
Current CPC
Class: |
F28D 19/047
20130101 |
Class at
Publication: |
165/4 |
International
Class: |
F28D 17/00 20060101
F28D017/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 28, 2009 |
EP |
09007145.7 |
Claims
1. A method for temperature-dependent setting of the sealing gap
between an adjustable seal and a revolving rotor of a regenerative
heat exchanger by means of at least one actuating apparatus which
comprises at least one rod body which is thermally influenced in an
alternating manner and whose temperature-dependent change in axial
length is converted into an actuating movement for the seal, with
this rod body being arranged at least in sections in at least one
chamber and a control medium flows through or about this chamber at
least in sections, which medium acts in a direct or indirect manner
in a thermally alternating fashion on said rod body, and with the
temperature level of the control medium corresponding to a
temperature level of a gas volume flow flowing through the rotor,
so that a change in axial length of this rod body is produced
depending on a temperature change of this gas volume flow and a
respective actuating movement for the seal is brought about,
wherein at least one actuating apparatus comprises several such rod
bodies which, by cooperation, produce an actuating motion for the
seal, with at least two of these rod bodies being separately
controllable via respective chambers by means of the control medium
in a thermally alternating manner, such that these rod bodies can
also be subjected to different temperatures.
2. A method according to claim 1, wherein a partial volume flow is
branched off as a control medium from a gas volume flow flowing
through the rotor and is supplied to at least one such rod body,
for which purpose this rod body is arranged at least in sections in
at least one chamber, with the branched-off partial volume flow
flowing at least partly through and/or around said chamber, so that
depending on a change in temperature this gas volume flow produces
a change in axial length of the rod bodies and a respective
actuating motion for the seal.
3. A method according to claim 2, wherein the partial volume flow
is recirculated to the same gas volume flow after having flowed
through and/or about the chamber or is introduced into another gas
volume flow flowing through the rotor.
4. A method according to claim 1, wherein additionally a sealing
gap measurement is performed by means of at least one sensor, on
the basis of which at least one relevant property of the control
medium or partial volume flow is changed by determination of a
control unit in order to bring about a required change in axial
length of this rod body and a respective actuating motion for the
seal.
5. A thermally controlled actuating apparatus for a regenerative
heat exchanger for setting a sealing gap between an adjustable seal
and a revolving rotor, with the actuating apparatus comprising an
actuating section with at least one rod body that can be influenced
in a thermally alternating manner and a mechanical actuating drive
in order to convert a temperature-dependent change in axial length
of the rod body into an actuating movement for the seal, with at
least one rod body that is influenced in a thermally alternating
manner being arranged at least in sections in at least one chamber
and this chamber being supplied directly or indirectly with a
control medium in order to produce an influence on this rod body in
a thermally alternating manner, wherein several cooperating rod
bodies are comprised which are arranged at least in sections in
separate chambers, such that a different temperature application of
these rod bodies is enabled.
6. An actuating apparatus according to claim 5, wherein the control
medium can flow through the chambers at least in part, for which
they comprise at least one inlet and at least one outlet.
7. An actuating apparatus according to claim 5, wherein the control
medium can flow about the chambers at least in part, for which
their walls are arranged with double walls and/or with a line
jacket.
8. An actuating apparatus according to claim 5, wherein a relative
movement between the rod bodies and the chambers is enabled.
9. An actuating apparatus according to claim 5, wherein these rod
bodies are arranged in a tubular way.
10. An actuating apparatus according to claim 5, wherein the
chambers are placed on the rod bodies.
11. An actuating apparatus according to claim 5, wherein the walls
of the chambers are provided with at least one bellows-like section
in order to enable a temperature-induced volume compensation.
12. An actuating apparatus according to claim 5, wherein at least
one first chamber is provided with an inlet for a non-heated or
cool control medium and at least one second chamber with an inlet
for a heated control medium, so that the rod bodies that are each
arranged in said chambers can be subjected to a defined temperature
difference by a respective supply of a control medium.
13. An actuating apparatus according to claim 12, wherein the first
chamber and the second chamber are in flow connection and the first
chamber is upstream of the second chamber with respect to a
preferred direction of flow of the control medium.
14. An actuating apparatus according to claim 13, wherein a heating
device for auxiliary heating of the control medium is arranged
between an outlet of the first chamber and the inlet of the
downstream second chamber.
15. An actuating apparatus according to claim 13, wherein a fan
device for auxiliary conveyance of the control medium is arranged
between the outlet of the first chamber and the inlet of the
downstream second chamber.
16. An actuating apparatus according to claim 13 wherein at least
one valve device is comprised for controlling the volume flow of
the control medium.
17. An actuating apparatus according to claim 5, wherein at least
one sensor is comprised for measuring the sealing gap.
18. An actuating apparatus according to claim 17, wherein a control
unit is comprised which controls a heating device, a fan device
and/or a valve device on the basis of the sensor measurement signal
of the sensor.
19. An actuating apparatus according to claim 5, wherein at least
two rod bodies are made of the same material.
20. An actuating apparatus according to claim 5, wherein at least
two rod bodies are made of different materials.
21. An actuating apparatus according to claim 5, wherein at least
one filter device is comprised.
22. A regenerative heat exchanger comprising at least one thermally
controlled actuating apparatus according to claim 5.
23. A regenerative heat exchanger according to claim 22, wherein
the seal which can be adjusted by means of the actuating apparatus
is a radial seal, a circumferential seal and/or a jacket seal.
24. A regenerative heat exchanger according to claim 22, wherein
the seal which can be adjusted by means of the actuating apparatus
is a radial seal and/or a circumferential seal on the cold rotor
side and/or on the hot rotor side.
25. A regenerative heat exchanger according to claim 22, wherein it
is operated with a method for temperature-dependent setting of the
sealing gap between an adjustable seal and a revolving rotor of a
regenerative heat exchanger by means of at least one actuating
apparatus which comprises at least one rod body which is thermally
influenced in an alternating manner and whose temperature-dependent
change in axial length is converted into an actuating movement for
the seal, with this rod body being arranged at least in sections in
at least one chamber and a control medium flows through or about
this chamber at least in sections, which medium acts in a direct or
indirect manner in a thermally alternating fashion on said rod
body, and with the temperature level of the control medium
corresponding to a temperature level of a gas volume flow flowing
through the rotor, so that a change in axial length of this rod
body is produced depending on a temperature change of this gas
volume flow and a respective actuating movement for the seal is
brought about, wherein at least one actuating apparatus comprises
several such rod bodies which, by cooperation, produce an actuating
motion for the seal, with at least two of these rod bodies being
separately controllable via respective chambers by means of the
control medium in a thermally alternating manner, such that these
rod bodies can also be subjected to different temperatures.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to EP application EP filed
May 28, 2009. The contents of EP are incorporated herein by
reference in their entirety.
BACKGROUND
[0002] 1. Related Field
[0003] The invention relates to a method for the
temperature-dependent setting of a sealing gap between an
adjustable seal and a revolving rotor of a regenerative heat
exchanger, according to the preamble of claim 1. The invention
further relates to an actuating apparatus concerning the same
according to the preamble of the alternative independent claim. The
invention further relates to a regenerative heat exchanger.
[0004] 2. Related Art
[0005] Regenerative heat exchangers of the kind mentioned above are
used for air preheating (APH) and/or gas preheating (GPH). For this
purpose, a heat-emitting and a heat-absorbing gaseous medium are
guided in counter-flow along heat storage bodies. The heat storage
bodies, e.g. heating element packs, are arranged in a stator or
rotor.
[0006] When the heat storage bodies are arranged in a rotor
(Ljungstrom principle) they are rotated through the cold and hot
gas flows, so that a continuous exchange of heat between the gas
flows is enabled. In the arrangement in a stator (Rothemuhle
principle), the heat exchange is enabled in such a way that
rotating gas conduit connections, so-called rotary hoods, are
arranged on both stator face sides, so that the gas flows rotate
through the stator. In both variants, all existing gas flows flow
through the heat storage bodies in an alternating fashion.
[0007] In order to prevent leakages, various rotor seals are
required both on a stator as well as especially on a rotor. These
are radial seals, circumferential seals and axial or jacket seals
on a rotor. As a result of changing thermal conditions, a
continuous readjustment of these seals is necessary in operation in
order to obtain defined sealing gaps. The following possibilities
are known for setting or readjusting the sealing gap:
[0008] Adjustment by hand (manual readjustment)
[0009] Multi-point adjustment via an actuator system with actuating
cylinders
[0010] Electric actuating drives which are controlled
automatically
[0011] A thermally controlled actuating apparatus for
temperature-dependent setting of a sealing gap is known from DE 2
162 248 A. The seals are then connected via spring bolts with
bellows which are influenced in a thermally alternating manner. An
enclosed gas volume is disposed in the closed bellows, which volume
is heated or cooled by the ambient operating gases, thus changing
the gas pressure, which can be utilized as an actuating force for a
seal. Furthermore, rod bodies are known from the state of the art
which are influenced in a thermally alternating manner and whose
temperature-dependent change in axial length is converted into an
actuating movement for the seal. These concepts are disadvantageous
in many respects.
[0012] In some embodiments, a an aspect of providing a simple,
automatic and cost-effective possibility for setting seals in a
regenerative heat exchanger is present.
[0013] This may be achieved by a method described herein. This is
further achieved by an actuating apparatus and a regenerative heat
exchanger with the feature of the alternative independent claims.
Preferred and advantageous further developments form the object of
the dependent claims.
[0014] Advantages may be achieved in respect of the method by a
method for temperature-dependent setting of the sealing gap between
an adjustable seal and a revolving rotor of a regenerative heat
exchanger by means of at least one actuating apparatus which
comprises at least one rod body which is thermally influenced in an
alternating manner and whose temperature-dependent change in axial
length is converted into an actuating movement for the seal. It is
provided that this rod body is arranged at least in sections in at
least one chamber a control medium flows through or about this
chamber at least partly or in sections, which medium acts in a
direct or indirect manner in a thermally alternating fashion on
said rod body, with the temperature level of the control medium
corresponding to a temperature level of a gas volume flow flowing
through the rotor, so that a change in axial length of this rod
body is produced depending on a temperature change of this gas
volume flow and a respective actuating movement for the seal is
brought about.
[0015] A rod body is a solid body which is characterized by an
axial longitudinal extension which is a multiple of its
cross-sectional dimensions. A rod body that is influenced in a
thermally alternating manner is made of a material which is
subjected to a change in volume determined by the thermal expansion
coefficient in the case of a change in temperature, leading, among
other things, to a change in the axial length.
[0016] A rod body that is influenced in a thermally alternating
manner is arranged at least in sections in a chamber. The
respective rod body is enclosed at least in sections by at least
one chamber or penetrates at least one such chamber. The walls of
such a chamber are preferably arranged to be fluid-tight. A control
medium can be introduced into such a chamber for a direct influence
in a thermally alternating manner, which control medium represents
in accordance with the invention a thermal level of the gas volume
flow passing through the rotor. The surface of the rod body can be
arranged accordingly for better heat exchange. It is similarly
possible to protect the surface of the rod body by a coating from a
control medium that acts aggressively for example. The control
medium can flow about this chamber for the purpose of an indirect
influence of the rod body in a thermally alternating manner, as
will be explained below in closer detail. Both possibilities can be
combined with one another.
[0017] The revolving rotor is used preferably for the heat transfer
from a first gas volume flow, e.g. a flue gas volume flow, to a
second gas volume flow such as a fresh-air or air-volume flow. Such
a technology is used especially in power plants.
[0018] A control medium can be a gaseous or fluid medium, which
needs to be arranged in such a way that it can flow through a
conduit system or the like. It is provided in accordance with the
invention that the temperature level of this control medium
corresponds with a temperature level of a gas volume flow flowing
through the rotor, which means that there is a mutual
correspondence. It can concern the first or second gas volume flow.
It is preferably provided that it concerns the second gas volume
flow, i.e. the air-volume flow, and its temperature level is
relevant for setting the sealing gap after flowing through the
rotor or at the rotor outlet (on the hot rotor side).
[0019] One basic principle of some embodiments of the invention
consists in the recognized correlation between the temperature
level of a gas volume flow flowing through the rotor and a rotor
deformation occurring at a specific temperature. Such a rotor
deformation is a crown of a rotor for example, as described in
detail in DE 2 162 248 A for example. This requires a setting of
the sealing gap by readjusting the seals. This concerns the radial
seals and the circumferential seals on both rotor sides and the
axial and jacket seals. This invention enables a simple, but highly
effective readjustment of rotor seals, through which the sealing
gap can be set in an optimal manner at any time in a quasi
automatic way under a large variety of operating conditions.
[0020] It is provided in accordance with some embodiments of the
invention that a temperature level of the control medium
corresponds to a temperature level of a gas volume flow flowing
through the rotor. This can be realized technically in different
ways. It is possible for example that the control medium is in
thermal connection with the gas volume flow via a heat exchanger.
It is further possible that a partial volume flow used as a control
medium is branched off from the gas volume flow. It is further
possible to detect a temperature of the gas volume flow by means of
measuring technique and thereafter to set the properties of the
control medium in a purposeful way. These possibilities can also be
combined with one another. A number of the possibilities will be
explained below in closer detail as preferred further
developments.
[0021] Some embodiments of invention may have many advantages such
as: [0022] The rod body/rod bodies that are influenced in a
thermally alternating manner and the chamber or chambers enclosing
the same can be arranged with independent location from one
another; [0023] the rod body/rod bodies that are influenced in a
thermally alternating manner are substantially subjected to only
one specific control medium; [0024] the invention can be
implemented for radial, circumferential and axial seals; [0025] the
respective seals automatically follow the rotor deformation in all
load changes; [0026] no electric, pneumatic, hydraulic and/or
comparable actuating drives are required; [0027] no electric wiring
is necessary; [0028] the sealing gaps can be adjusted individually
in a location-dependent manner also during operation; [0029] the
sealing gaps remain the same during operation, i.e. there is very
little leakage; [0030] long service life, and [0031] low
maintenance costs.
[0032] It is provided according to a preferred further development
that a partial volume flow is branched off as a control medium from
a gas volume flow flowing through the rotor and is supplied to at
least one such rod body, for which purpose this rod body is
arranged in sections in at least one chamber, with the branched-off
partial volume flow flowing at least partly through and/or around
said chamber, so that depending on a change in temperature this gas
volume flow produces a change in axial length of this rod body and
a respective actuating motion for the seal. The partial volume flow
is preferably branched off at the hot rotor side from the second
gas volume flow, i.e. the air volume flow. After the branching, the
partial volume flow can further be subdivided into several partial
volume flows.
[0033] It is provided according to a preferred further development
that the branched-off partial volume flow is recirculated to the
same gas volume flow after having flowed through and/or about the
chamber or is introduced into another gas volume flow flowing
through the rotor. As a result, a partial volume flow branched off
from the air volume flow is recirculated to the air volume flow or
is introduced into the flue gas volume flow. The recirculation or
introduction can occur before the entrance of the respective gas
volume flow into the rotor or after the same. As a result of
skilled recirculation or introduction, a pressure difference
against the branch-off can be utilized which drives the partial
volume flow. Such a measure is further advantageous from an energy
point of view.
[0034] It is provided according to a preferred further development
that additionally a sealing gap measurement is performed by means
of at least one sensor, on the basis of which at least one relevant
property of the control medium or partial volume flow is changed
under determination or control of a control unit in order to bring
about a required change in axial length of this rod body and a
respective actuating motion for the seal. Relevant properties of
the control medium or partial volume flow are especially its
pressure, temperature and flow volume. These properties can be
influenced for example by heating and/or cooling and by a fan. It
is the idea that by influencing the control medium or the partial
volume flow, a defined change in length of a rod body is produced
or controlled, thus causing a defined actuating motion for the
seal.
[0035] It is provided according to a preferred further development
that an actuating apparatus comprises several such rod bodies
which, by cooperation, produce an actuating motion for the seal,
with at least two of these rod bodies being separately controllable
via respective chambers by means of the control medium or partial
volume flow in a thermally alternating manner. This will be
explained below in closer detail in connection with the
drawings.
[0036] It is provided according to an especially preferred further
development that a firstly cold control medium is supplied to at
least one rod body and is heated thereafter in order to be supplied
to further rod bodies. A good control precision can thus be
achieved with respect to the sealing gap. This will be explained
below in connection with the drawings.
[0037] This object is achieved in respect of the apparatus by a
thermally controlled actuating apparatus for a regenerative heat
exchanger for setting a sealing gap between an adjustable seal and
a revolving rotor, with the actuating apparatus comprising at least
one rod body that is influenced in a thermally alternating manner
and whose temperature-dependent change in axial length is converted
into an actuating motion for the seal. It is provided that at least
one rod body that is influenced in a thermally alternating manner
is arranged at least in sections in at least one chamber and this
chamber can be supplied directly or indirectly with a control
medium which causes the (direct or indirect) influencing in a
thermally alternating manner of this rod body.
[0038] The statements made above in connection with the method in
accordance with the invention apply to this actuating apparatus
analogously and vice-versa. A branched-off partial volume flow of a
gas volume flow heated by the rotor is preferably provided as a
control medium. The actuating apparatus in accordance with the
invention is especially suitable for performing the method in
accordance with the invention and is provided for this purpose.
[0039] It is provided according to a preferred further development
that the control medium can flow at least partly or in sections
through the chamber, for which purpose it comprises at least one
inlet and at least one outlet. This leads to a direct or indirect
influencing of the rod body in a thermally alternating manner. Such
a chamber can be arranged as a through-flow chamber. This will be
explained below in closer detail in connection with the
drawings.
[0040] It is provided according to a preferred further development
that the control medium can flow about the chamber at least partly
or in sections, for which purpose its walls are arranged to have
double walls (i.e. with an enclosed cavity) and/or with a
conducting jacket. This leads to an indirect influence of the rod
body in a thermally alternating manner.
[0041] It is provided according to a preferred further development
that a relative motion is enabled between this rod body and the
chamber. Alternatively, no relative motion is enabled between this
rod body and the chamber.
[0042] It is provided according to a preferred further development
that this rod body is arranged as a tube. Preferably, the tube has
a cross section in the shape of circular ring, with other
cross-sectional shapes being possible. Massive arrangements are
also possible.
[0043] It is provided according to a preferred further development
that the chamber is placed on the rod body. Preferably, the chamber
is fixed to this rod body and completely encloses the same in the
radial direction. The length of the chamber corresponds to
approximately 60 to 80% of the axial length of the rod body in the
axial direction, so that it preferably projects or protrudes beyond
the chamber at both axial ends. Several chambers can also be
provided in the axial direction of the rod body which can be
supplied differently with control media for example.
[0044] It is provided according to a preferred further development
that the walls of the chamber are provided with at least one
bellows-like section which enables a temperature-induced volume
compensation. This will be explained below in closer detail in
connection with the drawings.
[0045] It is provided according to a preferred further development
that several of these rod bodies are comprised which are arranged
at least in sections parallel and/serially in a chamber. It is also
possible that several such chambers are provided in which one group
each of rod bodies is arranged. The number of the rod bodies
jointly arranged in a chamber can be different. It is provided
alternatively and/or additionally that several of these rod bodies
are comprised which are arranged at least in sections in separate
chambers. As a result, this encompasses all technically possible
combinations of arrangements.
[0046] If a plurality of rod bodies is comprised, it is provided
according to a preferred further development that at least two rod
bodies are made of the same material. In particular, all rod bodies
are made of the same material. Even in the case of a similar choice
of material, the rod bodies can expand or contract differently as a
result of different axial lengths and/or temperature stresses. It
is provided alternatively and/or additionally that at least two rod
bodies are made of different materials.
[0047] It is provided according to a preferred further development
that at least one first chamber is provided with an inlet for
non-heated or cool control medium such as air and at least one
second chamber with an inlet for a heated control medium, so that
the rod bodies that are arranged in said chambers can be subjected
to a defined temperature difference by a respective supply of a
control medium (air). It is the idea that an independent system is
created with an adjustable temperature for the control medium or an
adjustable flow volume, with which the axial change in length can
be influenced in a purposeful manner. This will be explained below
in closer detail in connection with the drawings.
[0048] It is provided according to a preferred further development
that the first chamber and the second chamber are in flow
connection and the first chamber is provided upstream of the second
chamber with respect to a preferred direction of flow of the
control medium. The flow connection is realized by means of a
tubing system. A preferred tube diameter of this tubing system is
approximately 20 mm. This will be explained below in closer detail
in connection with the drawings.
[0049] According to a preferred further development, the system
comprises at least one heating and/or cooling device. It is
especially provided that a heating device for auxiliary heating of
the control medium is arranged between an outlet of the first
chamber and the inlet of the downstream second chamber. Preferably,
such a heating device is embedded in a possible tubing system.
Preferably, this heating device can be bridged for example by means
of a bypass for example. This is especially considered in the case
that the control medium is at least partly a warm or hot partial
volume flow which is branched off or derived from a gas volume flow
passing through the rotor. An additional heating might not be
necessary in this case. Cooling might be necessary however. This
will be explained below in closer detail in connection with the
drawings.
[0050] At least one blower device is comprised according to a
preferred further development. It is especially provided that
between the outlet of the first chamber and the inlet of the
downstream second chamber a blower device is arranged for auxiliary
conveying of the control medium. Preferably, such a blower device
is embedded in a possible tubing system. The blower device can
possibly be used to increase the pressure in the control medium.
This will be explained below in closer detail in connection with
the drawings.
[0051] At least one valve device is comprised according to a
preferred further development. It is especially provided that at
least one valve device is comprised for controlling the volume flow
of the control medium. Preferably, such a valve device is embedded
in a possible tubing system. This will be explained below in closer
detail in connection with the drawings.
[0052] At least one filter device is comprised according to a
preferred further development. It is especially provided that this
filter device is arranged before the rod bodies in the direction of
flow and should prevent potential dirt deposits on the rod bodies.
Preferably, such a filter device is embedded in a possible tubing
system.
[0053] At least one sensor for measuring the sealing gap is
comprised according to a preferred further development.
[0054] A control unit is comprised according to a preferred further
development. It is especially provided that this control unit or
control device controls a heating device and/or a cooling device, a
blower device and/or a fan device on the basis of the sensor
measurement signal. The control unit preferably concerns an
electronic control unit which especially comprises a software-based
control algorithm.
[0055] The object is further achieved in respect of the apparatus
by a regenerative heat exchanger, comprising at least one thermally
controlled actuating apparatus in accordance with the invention. It
is especially provided that this regenerative heat exchanger is or
can be operated according to the method in accordance with the
invention. The statements made above apply in an analogous manner
to this regenerative heat exchanger.
[0056] According to a preferred further development of this
regenerative heat exchanger, it is provided that the seal which is
adjustable by means of the actuating apparatus is a radial seal, a
circumferential seal and/or a jacket seal. It is especially
provided that the seal which is adjustable by means of the
actuating apparatus in accordance with the invention is a radial
seal and/or a circumferential seal on the cold rotor side and/or
the hot rotor side.
[0057] The will be explained below by reference to the drawings
that show schematically:
BRIEF DESCRIPTION OF THE FIGURES
[0058] FIG. 1 shows the rotor of a regenerative heat exchanger in a
side view;
[0059] FIG. 2 shows an embodiment of an actuating apparatus in
accordance with the invention in a sectional view;
[0060] FIG. 3 shows an alternative embodiment of an actuating
apparatus in accordance with the invention in a sectional view;
[0061] FIG. 4 shows a further embodiment of an actuating apparatus
in accordance with the invention with an exemplary wiring, and
[0062] FIG. 5 shows the progress over time of the rod body
temperature at a temperature jump of the control medium in a
diagram.
DETAILED DESCRIPTION
[0063] FIG. 1 shows a rotor designated in its entirety with
reference numeral 1 of a regenerative heat exchanger. Rotor 1
comprises a vertical rotation axis 2. The rotation direction is
indicated by way of example with the arrow R. A first gas volume
flow 3, which can concern a hot flue gas volume flow for example,
and a second gas volume flow 4, which can concern a cool air volume
flow for example, flow in opposite directions through the rotor 1.
Heat from the first gas volume flow 3 is transferred to the second
gas volume flow 4 by means of rotor 1, through which the first gas
volume flow 3 cools off during passage through the rotor 1 and the
second gas volume flow 4 is heated up during the passage through
the rotor 1. As a result of the existing temperature conditions,
the upper rotor face side can be designated as the hot face side
(or rotor side) A and the bottom rotor face side as the cold face
side (or rotor side) B. A sealing gap is designated with U by way
of example.
[0064] Circumferential seals 7a and 7b, radial seals 8a and 8b, and
axial seals or jacket seals 9a and 9b are provided to prevent
leakages on the rotor 1. These seals 7a, 7b, 8a, 8b, 9a, 9b can be
arranged in a segmented manner. As a result of the changing thermal
conditions, it is necessary to continually readjust these seals in
operation in order to maintain defined sealing gaps. This
readjustment of the seals 7a, 7b, 8a, 8b, 9a, 9b occurs by means of
at least one actuating apparatus 10 in accordance with the
invention, as will be explained below in closer detail. Several
such actuating apparatuses 10 can be provided for a seal 7a, 7b,
8a, 8b, 9a, 9b, which actuating apparatuses are operated in an
autonomous fashion or in agreement with one another.
[0065] FIG. 2 shows a simple embodiment of an actuating apparatus
10 in accordance with the invention in a schematic sectional view.
The actuating apparatus 10 is fixed in a stationary manner to a
housing section or frame 5 of the regenerative heat exchanger. The
actuating apparatus 10 comprises an actuating unit 11 and an
actuating section or actuating drive 12. Several rod bodies 13 and
14 are arranged in the actuating section, the axial length of which
varies depending on a momentary temperature. The rod bodies 13 are
provided with the same axial lengths and shorter than the rod body
14.
[0066] The outer rod bodies 13, the arrangement of which on the
outside is merely exemplary, are fixed with their axial ends on the
left side to a fixed bearing 15. In the case of a
temperature-induced change in axial length of the rod bodies 13,
these changes in length are transferred to the floating bearing 16
on the right side. The translational movement V on the floating
bearing 16 is transferred via the rod body 14 to a tilting lever 20
which moves the respective seal via an adjusting bolt 21, which is
indicated by a double arrow X. The threaded nuts 22 are used for
manually adjusting the seal. The illustrated lever mechanism is
merely exemplary. Other mechanical actuating drives can thus be
readily realized. Similarly, the illustrated diagonal arrangement
of the rod bodies 13 and 14 is merely exemplary.
[0067] The rod bodies 13 are made of a material which has a large
amount of volume change in the case of changes in temperature. The
rod body 14 is made of a material which has a considerably lower
change in volume at the same amount of change in temperature, so
that changes in length of the rod bodies 13 are not compensated by
a change in length of this rod body 14. The actuating mechanism can
also be described as follows: the rod bodies 13 with a high thermal
expansion initiate an actuating movement which is transferred via
at least one rod body 14 with a low thermal expansion to the
actuating drive 12. The number of the individual types of rod
bodies is merely exemplary, with it being preferable that several
rod bodies 13 are provided which can produce high actuating forces.
The rod bodies 13 are subjected to pressure and can therefore be
designated as pressure rods. The rod body or bodies 14 are
subjected to tensile stress and can therefore be designated as
tension rods.
[0068] The rod bodies 13 and 14 are arranged in a chamber 17 which
is formed by a fluid-tight wall 17a. In the illustrated embodiment,
the rod bodies 13 and 14 are completely enclosed by the chamber 17.
Chamber 17 comprises an inlet 18 and an outlet 19 by way of
example. A control medium can flow through the chamber 17 via the
inlet 18 and the outlet 19, which is indicated by the flow arrows.
The control medium flows directly around the rod bodies 13 and 14,
which subsequently assume the current temperature of the control
medium. A change in temperature in the control medium causes a
change in axial length of the rod bodies 13, through which an
actuating movement X for the seal is initiated, as already
explained above.
[0069] A gaseous medium is preferred as a control medium. It is
especially provided that a partial volume flow is used as a control
medium which is branched off from the second gas volume flow to be
heated or the air flow 4 after its passage through the rotor 1,
i.e. on the hot face side A of rotor 1. As a result of a
correlation between the temperature of this gas volume flow 4 on
the hot face side A of rotor 1 and an obtained rotor deformation,
the actuating apparatus 10 can be set mechanically in such a way
that the respective seal is readjusted at a specific change in
temperature with a defined path, which then occurs in a quasi
automatic manner. A specific actuating path length X can be
determined for example by the transmission ratio in the mechanical
actuating drive 12 or by choosing the material of the rod body 13
and 14 or its geometric dimensions.
[0070] If necessary, the reaction time can be varied via the flow
volume and/or the flow pressure of the control medium in the
chamber 17, which reaction time is needed by the rod bodies 13 and
14 in order to adjust to the current temperature of the control
medium. In order to enable changing the flow volume and/or the flow
pressure, a heating and/or cooling device and a fan device can be
comprised. It can further be necessary under certain circumstances
to change the properties of the control medium in a purposeful way
in order to thus produce a desired actuating movement X for the
seal. This will be explained below in closer detail in connection
with a further embodiment on the basis of FIG. 3.
[0071] FIG. 3 shows an alternative embodiment of an actuating
apparatus 10. Its configuration is substantially identical to the
configuration as shown in FIG. 2. It is provided in a deviating
manner in this case that the control medium does not flow directly
about the rod bodies 13 and 14 and there is thus no direct
influence in an alternating thermal manner, but that the control
medium is guided through a hollow chamber 17b in wall 17a and thus
does not come into direct contact with the rod bodies 13 and 14,
for which purpose the wall 17a is provided with a double wall. The
rod bodies 13 and 14 are influenced in an alternating thermal
manner only indirectly in that the control medium transfers its
temperature level to the air (possibly also a gas or a fluid)
enclosed in chamber 17. Such an arrangement offers advantages
concerning sealing for example. Furthermore, aggressive control
media can also be used without having a negative effect on the
seals and/or the rod bodies 13 and 14. Instead of a hollow chamber
17b or in addition thereto, the wall 17a of the chamber 17 can also
be enclosed at least in sections by a sheath of lines such as
spiral flow line through which the control medium will flow.
[0072] In accordance with FIG. 4, an alternative actuating
apparatus 10 comprises a rod body 14 arranged as a tension rod and
several rod bodies 13 arranged as pressure rods. They are each
enclosed in a fluid-tight chamber 171 and 172 which are arranged in
this case as hollow-cylindrical jackets with circular face sides.
The chambers 171 and 172 are arranged as through-flow chambers with
direct flow through the same. The chambers 171 and 172 are quasi
placed from the outside on rod bodies 13 and 14. The chambers 171
and 172 are part of a flow or tubing system which comprises an
inlet 181, several connecting lines 40, one outlet 192, several
valves or valve devices 51 to 54, a filter device 60, a
controllable fan device 60, and a controllable electric heating
device 70. The two through-flow chambers 171 and 172 are switched
behind one another. The connecting lines 40 of the tubing system
have an inside diameter of approx. 20 mm for example.
[0073] The pressure rods 13 and the tension rod 14 are arranged
parallel with respect to one another and enable a
temperature-dependent adjustment of a seal in the manner as
explained above, with a circumferential seal 7 being concerned in
this case by way of example. The sealing gap to rotor 1 is
designated with U. Whereas the pressure rods 13 are held in a rigid
manner on a fixed bearing 15 at their upper axial ends, the bottom
axial ends can move in a floating bearing 16. This movement in the
floating bearing 16 is transferred via the tension rod 14 and a
lever rod assembly (not shown in closer detail) as an actuating
movement to the seal 7, which is designated in lieu with U. The
pressure rods 13 and the tension rod 14 have different coefficients
of thermal expansion for this purpose. Alternatively or in
addition, they can be arranged with different cross sections. In
the illustrated example, the rod bodies 13 and 14 are further
arranged with different axial lengths.
[0074] In a preferred constructional arrangement, the rod bodies 13
and/or 14 are arranged as round rods with a rod diameter of approx.
10 to 20 mm. Their axial length is approx. 2 m for example. The
chambers 171 and 172 are preferably arranged in a
circular-cylindrical manner and have an inside diameter of approx.
100 mm for example.
[0075] The chambers 171 and 172 have a substantially unchanged
volume. A control medium can be guided through these chambers 171
and 172 (through-flow chambers), which medium has a direct thermal
influence on the pressure rods 13 and the tension rod 14. the
chambers 171 and 172 are rigidly connected at their face sides with
the associated tension and pressure rods 13 and 14. In order to
compensate the temperature-induced changes in length, the walls of
the chambers 171 and 172 comprise bellows 173 and 174.
[0076] In the illustrated embodiment, unheated ambient air is drawn
at a temperature of 20.degree. C. for example via the inlet 181 at
one end into the chambers 171 which enclose the pressure rods 13.
This "air" is used subsequently as a control medium. It flows about
the pressure rods 13 virtually over their entire complete length
and is then discharged via the outlet 191 at the other end. From
there it reaches the electric heating device 70 via a connecting
line 40 where it is heated before it is supplied to the inlet 182
of the chamber 172 which encloses the tension rod 14. If required,
the heating device 70 can also concern a cooling device or a
combined heating/cooling device. The output of the heating device
70 is controlled by a control unit 80 which communicates with a
sensor 90 for example for measuring the sealing gap U. A fan device
60 is further arranged in the connecting line 40, which is used to
produce the flow in the tubing system or at least to support the
same. The fan device 60 can also be controlled by the control unit
80. Moreover, a filter unit 50 is arranged upstream of the heating
device 70 which especially removes solids from the control medium
or the air.
[0077] The air heated by means of the heating device 70 and/or the
fan device 60 is finally discharged via the outlet 192 after having
flowed along the tension rod 14 over virtually its entire length,
and is preferably supplied to the gas volume flow 4 to be heated
(not shown).
[0078] The rod bodies 13 and 14 can be subjected to different
temperatures with the illustrated arrangement. This leads to a good
controllability. Furthermore, it is possible to provide an indirect
control of a sealing gap depending on the temperature of the gas
volume flows and a partial volume flow which is possibly branched
off from the same. It thus offers the advantage that a flow along
the rod bodies 13 and 14 specifically predetermined by the chambers
171 and 172 can be produced, so that a defined heat transfer to the
rod bodies 13 and 14 is ensured. It is thus also possible to easily
determine the dependence on the changes in axial length or the flow
volume of the air (or the control medium) and to set the sealing
gap U on seal 7 in this way. Since the invention can be arranged as
an independent system, it can be used in many ways. Because of the
relatively simple components, the system works reliably and can be
built at low cost.
[0079] As an alternative to or in support of the heating device 70
and/or the fan device 60, the heated air can also be branched off
from the hot face side of the rotor 1 and be supplied via a further
inlet 41 to a node 42 in the connecting line 40. The feeding is
controlled by the valves 51 and 52, which can also be controlled by
the control unit 80. It is generally prevented by closing the valve
51 that an undesirable return flow of the heated air to the
pressure rods 13 occurs.
[0080] A bypass 44 with a valve 53 arranged therein leads about the
heating device 70, with which the air can optionally be guided past
the heating device 70. The flow volume of the air through the
heating device 70 can be blocked off partially or completely via
the downstream valve 54. The valves 53 and 54 are also used for
determining the flow volume and optionally the temperature of the
air at the inlet 182 by the mixing ratio. The valves 53 and 54 are
also controlled by the control device 80. A bypass is also possible
on the fan device 60 and/or the filter device 50.
[0081] FIG. 5 shows the time progression of the rod body
temperature S at a jump of the temperature L of the control medium
in a diagram. It can be recognized that the rod body temperature S
approaches the temperature L of the control medium flowing through
the chamber 17 (or 171 and/or 172) in a temporally sluggish manner,
with the axial change in length occurring in synchronicity with
this progression S. This temporal behavior must ideally be
considered in the configuration of the actuating apparatus 10. The
temporal behavior can be influenced for example via the fan device
60 and/or the heating/cooling device 70, which is then optionally
initiated by the control device 80.
* * * * *