U.S. patent application number 13/129000 was filed with the patent office on 2011-09-08 for insulating cartridge.
This patent application is currently assigned to RWE POWER AKTIENGESELLSCHAFT. Invention is credited to Ulrich Knitt.
Application Number | 20110214770 13/129000 |
Document ID | / |
Family ID | 42104974 |
Filed Date | 2011-09-08 |
United States Patent
Application |
20110214770 |
Kind Code |
A1 |
Knitt; Ulrich |
September 8, 2011 |
INSULATING CARTRIDGE
Abstract
The invention relates to an insulating cartridge for use as part
of a pipe jacket insulation, comprising a substantially closed
sheet metal casing (5) which completely encloses an insulating
material filling (7). The insulating cartridge (2) according to the
invention is characterized in that the insulating material filling
(7) comprises a silicate aerogel.
Inventors: |
Knitt; Ulrich; (Xanten,
DE) |
Assignee: |
RWE POWER
AKTIENGESELLSCHAFT
Essen
DE
|
Family ID: |
42104974 |
Appl. No.: |
13/129000 |
Filed: |
October 30, 2009 |
PCT Filed: |
October 30, 2009 |
PCT NO: |
PCT/EP09/07772 |
371 Date: |
May 12, 2011 |
Current U.S.
Class: |
138/32 |
Current CPC
Class: |
F22B 37/36 20130101;
F16L 59/024 20130101 |
Class at
Publication: |
138/32 |
International
Class: |
E03B 7/12 20060101
E03B007/12 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 12, 2008 |
DE |
10 2008 056 987.9 |
Claims
1. An insulating cartridge as part of a jacket of devices of a
steam generator which are under media pressure, for example as pipe
casing insulation, with an essentially closed sheet metal housing
which completely encloses an insulating material filling,
characterized in that the insulating material filling comprises an
aerogel.
2. The insulating cartridge as claimed in claim 1, characterized in
that the insulating material filling comprises an inorganic
areogel.
3. The insulating cartridge as claimed in claim 1, characterized in
that the insulating material filling comprises a silicate
aerogel.
4. The insulating cartridge as claimed in claim 1, characterized in
that the insulating material filling comprises an aerogel as a
granulate, preferably with a mean grain size of 0 to 4 mm.
5. The insulating cartridge as claimed in claim 1, characterized in
that the insulating material filling comprises at least one aerogel
molding.
6. The insulating cartridge as claimed in claim 5, characterized in
that the molding is adapted to the configuration of the preferably
dimensionally stable sheet metal housing.
7. The insulating cartridge as claimed in claim 1, characterized in
that the aerogel has increased infrared reflectivity.
8. The insulating cartridge as claimed in claim 7, characterized in
that the insulating material filling comprises graphite powder
and/or metal oxide powder.
9. The insulating cartridge as claimed in claim 7, characterized in
that the insulating material filling comprises aerogel and graphite
power and/or metal oxide powder in a homogeneous mixture, the
fraction of graphite powder and/or metal oxide powder being between
1.5 and 4.5 ma %.
10. The insulating cartridge as claimed in claim 1, characterized
in that it has an approximately C-shaped cross section and is
provided with fastening means by which insulating cartridges
designed complementarily to one another can be assembled to form an
essentially closed pipe casing.
Description
[0001] The invention relates to an insulating cartridge as part of
a jacket of devices of a steam generator which are under media
pressure, for example as pipe casing insulation, with an
essentially closed sheet metal housing which completely encloses an
insulating material filling.
[0002] Such an insulating cartridge is often used for the thermal
insulation of pipe lines at steam generators.
[0003] The known insulating cartridges are sheet metal cartridges
which are in the form of half shells and are filled with mineral
wool, glass fiber wool or similar insulating materials. These are
described, for example, in DE 29 23 094 A. In the cold insulation
and thermal insulation of pipe lines, it is customary to provide
insulating materials with a jacket which protects the insulating
material against climatic conditions and mechanical damage. The
jacket of the insulation is frequently carried out by sheeting the
insulating material, for example with sheet zinc. In some
applications such as, for example, in coolant circuits of nuclear
power stations it has proved appropriate to use closed insulating
cartridges which completely enclose the insulating material. In
particular, the sheet metal housing of the insulating cartridges is
intended to afford sufficient protection against mechanical damage
to the insulating material. However, in accidents involving the
loss of coolant in nuclear power stations, it may nevertheless
happen that the metal cartridge is destroyed and the insulating
material contained in it escapes. For example, the situation could
arise where the leakage jet from a coolant line causes an
insulating cartridge to be broken off and destroyed. Insulating
cartridges of the type described above are provided, for example,
for lines with a diameter of up to about 800 mm and an internal
pressure of 160 bar at a media temperature of about 300.degree. C.
It can easily be imagined that the leakage jet from such a line may
introduce relatively high mechanical forces into the insulating
cartridge.
[0004] In this case, it could happen in theory that the sheet metal
housing of an insulating cartridge breaks and the insulating
material is flushed out by the leakage jet of the coolant. The
washed-out insulating material could block the intake screens of
the pumps provided in the reactor sump, with the result that it
becomes difficult to bring the accident under control.
[0005] It became apparent that there was a fundamental problem in
retaining or keeping out fibrous insulating materials by means of
screens. Laboratory tests showed that the fiber material, on the
one hand, is difficult to retain by means of relatively fine-meshed
screens and, on the other hand, generates high pressure losses
across the screens during its accretion. This may lead to the
failure of the screens.
[0006] The object on which the invention is based, therefore, is to
improve in this respect an insulating cartridge of the type
initially mentioned.
[0007] The object on which the invention is based is achieved by
means of an insulating cartridge as part of a jacket of devices of
a steam generator which are under media pressure, for example as
pipe casing insulation, with an essentially closed sheet metal
housing which completely encloses an insulating material filling,
the insulating cartridge being distinguished in that the insulating
material filling comprises an aerogel. Aerogel is to be understood
generally and in the context of the invention as meaning highly
porous solids in which up to 95% of the volume is composed of
pores. Using this material as filling material for an insulating
cartridge has the advantage that, for example, material emerging
from the insulating cartridge can be kept out of a water circuit
more easily by virtue of its physical properties.
[0008] Preferably, the insulating material filling provided is an
inorganic aerogel which is non-wettable, is floatable and is
incombustible. An insulating cartridge in which the insulating
material filling comprises a silicate aerogel has proved to be
especially advantageous. Such silicate aerogels may have, for
example, a pore diameter of about 20 nm with a porosity of >90%.
The density of the material may amount to between 90 and 100
kg/m.sup.3. Thermal conductivity may amount, for example, to about
0.018 W/mK at 25.degree. C. Such material may have an internal
surface area of about 600 to 800 m.sup.2/g. The material is
therefore predominently suitable as insulating material for the
purposes described above.
[0009] For example, what may be used as a suitable silicate aerogel
is material bearing the commercial designation "Nanogel" which is
sold by the company CABOT Corporation.
[0010] In an expedient variant of the insulating cartridge
according to the invention, there is provision for the insulating
material filling to comprise an aerogel as a granulate, preferably
with a mean grain size of 0 to 4 mm. Such a granulate possesses, in
particular, handling benefits. It can be decanted into
corresponding filling orifices of sheet metal cartridges. The
insulating cartridges can be filled with the highest possible
packing density.
[0011] Alternatively, the insulating material filling may comprise
at least one aerogel molding. Such a molding could be adapted to
the configuration of the preferably dimensionally stable sheet
metal housing. The sheet metal housing of the insulating cartridges
may be composed, for example, of austenitic steel. In an especially
preferred variant of the insulating cartridge according to the
invention, there is provision for the aerogel to be
non-translucent. A correspondingly treated aerogel may be used for
this purpose. The advantage of this is that the infrared
reflectivity of the sealing material used is increased and
therefore the insulating action is improved.
[0012] For this purpose, for example, the insulating material
filling may comprise graphite powder and/or metal oxide powder. The
powder may, for example, be in a homogeneous mixture with an
aerogel granulate. For example, the insulating material filling may
comprise aerogel and graphite powder and/or metal oxide powder in a
homogeneous mixture, the fraction of graphite powder and/or metal
oxide powder being between 1.5 and 4.5 ma %.
[0013] Expediently the insulating cartridge according to the
invention has an approximately C-shaped cross section and is
provided with fastening means by which insulating cartridges
designed complementarily to one another can be assembled to form an
essentially closed pipe casing.
[0014] Within the scope of the invention, however, the insulating
cartridge may be adapted to any desired contour of a media-carrying
device to be insulated.
[0015] The invention is explained below by means of an exemplary
embodiment illustrated in the drawings in which:
[0016] FIG. 1 shows a diagrammatic view of a pipe line which is
clad with insulating cartridges according to the invention,
[0017] FIG. 2 shows a top view along the arrows II-II in FIG.
1,
[0018] FIG. 3 shows a longitudinal section along the arrows III-III
in FIG. 2,
[0019] FIG. 4 shows an exploded view of an alternative embodiment
of the insulating cartridge according to the invention, and
[0020] FIG. 5 shows the insulating cartridge from FIG. 5 in the
assembled state.
[0021] FIG. 1 shows a pipe line portion 1 of a high-temperature
pipe line carrying a medium which is under pressure. The pipe line
portion 1 is clad with insulating cartridges 2 according to the
invention, the insulating cartridges 2 having in each case a
C-shaped cross-sectional profile, and two mutually complementary
insulating cartridges 2 being assembled in each case with fastening
means 3 to form a closed tubular insulating jacket 4. What may be
considered as fastening means are, for example, known shackle-type
toggle fastenings. Each insulating cartridge 2 is composed of a
riveted or welded sheet metal housing 5, preferably made from
austenitic sheet steel. The sheet metal housing is closed over the
entire circumference and on the end faces 6 and is provided with an
insulating material filling 7. In the variant of the insulating
cartridges 2 which is shown in FIGS. 1 to 3, these comprise an
insulating material filling in the form of a granulate of a
silicate aerogel. Here, this is a granulate with a mean grain size
of 0 to 4 mm, comprising trimethylsilyloxy-modified silica gel as
the main component. This has a porosity of >90%, a pore diameter
of about 20 nm, a bulk density of between 90 and 100 kg/m.sup.3 and
a thermal conductivity of about 0.18 W/mK at 25.degree. C. The
specific surface area amounts to between 600 and 800 m.sup.2/g. The
aerogel is incombustible and non-wettable and floatable.
[0022] The granulate is introduced into the insulating cartridges
through orifices 8 provided on the end faces of the latter. The
orifices 8 are subsequently closed by means of covers 9. The covers
9 may be welded, screwed or riveted.
[0023] FIGS. 4 and 5 show a further exemplary embodiment of the
insulating cartridge 2 according to the invention. The insulating
material filling 7 is formed as a molding 10, the configuration of
which is adapted to the configuration of the dimensionally stable
sheet metal housing 5.
[0024] The molding 10 is inserted with a fit into the sheet metal
housing 5, the end face 6 of which is closed by means of a
correspondingly formed cover 9.
[0025] The areogel, either in the form of the granulate or of the
molding 10, is improved in terms of its infrared reflectivity, that
is to say its insulating properties with regard to thermal
radiation, by means of coloring. For example, dusting of the
molding 10 with graphite powder and/or metal oxide powder may be
considered. The granulate may be mixed with graphite powder and/or
metal oxide powder, the graphite powder and/or metal oxide powder
having a fraction of 1 to 4 ma % in the mixture.
LIST OF REFERENCE SYMBOLS
[0026] 1 Pipe line portion [0027] 2 Insulating cartridge [0028] 3
Fastening means [0029] 4 Insulating jacket [0030] 5 Sheet metal
housing [0031] 6 End faces [0032] 7 Insulating material filling
[0033] 8 Orifices [0034] 9 Cover [0035] 10 Molding
* * * * *