Note: Descriptions are shown in the official language in which they were submitted.
The present invention relates to a regenerator for a
regenerative heating system.
Around 50% of the fuel gas used in high temperature
processes is used in plant producing dirty waste gas.
Such processes include glass smelting and the melting of
non-ferrous metals~ These waste gases may include solid,
unreacted contaminated Material resulting from the charge
being processed or other contaminants in the form of
vapour phase compounds which condense as the waste gas i8
cooled.
Although these waste gases are a far from ideal source of
recoverable heat for ~he preheating of combustion air for
the fuel gas, attempts have been made to harness their
potential for the preheat of combustion air utilising
conventional regenerative heating systems.
Small scale heat recovery systems such as recuperative
burners have in general been unsuitable as heat recovery
systems because of the tendency for the flue twaste) gas
psssages in these burners to become blocked with the
material carried over with the flue gases. In addition,
many of the contaminants are highly corrosive to the
metals from which the recuperative burners are made.
On the other hand, when regenerative heating systems using
conventional regenerators have been used to extract the
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waste heat from the waste gases, the heat storage bed~
through which the gase6 pass have required extensive
cleaning and maintenance aft2r u~e due to their
contamination and blockage by the waste gaæ contaminants.
It is therefore an ob~éct of the present invention to
provide a regenerator for a regenerative heating ~ystem
in which the~e problems are overcome.
According therefore to the present invention, a
regenerator i6 provided for a regenerative heating
system, the regenerator comprising an inner imperforate
chamber for storing a heat storage bed in the form of
discrete particle~, a closable inlet for introducing
fresh; particles into the inner ¢hamber to replace
contaminated particles;
a closable outlet for removing the contaminated
particles from the inner chamber BO that the fresh
particles may be introduced;
an outer chamher surrounding the inner chamber and
cerving to receive wa~te ga~ from the inner chamber after
passage through the inner chamber or to supply air for
heating in the inner chamber, the outer chamber serving
either to discharge the waste gas from the regenerator or
to receive air for heating in the regenerator; and
a clo~ure a~embly extending from ~aid inner chamber
through ~aid outer chamber to said clo~able outlet, said
closure assembly compri6ing a funnel-shaped cage portion
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tapered toward~ 6ai~ closable outlet an~ a connecting
cage portion connected between a tapered end of said
funnel-~haped cage portion and said closure outlet, 6aid
closure assembly containing a portion of said heat
storage bed and providing communication between said
inner and outer chambers.
An embodiment of the invention will now be particularly
de~cribed with reference to the accompanying drawings in
which:-
Figure 1 shows a ~ide view in section of a regenerator inaccordance with the present invention and
Figure 2 6hows in close up a ~ide view in section of the
lower part of the regenerator shown in Figure 1.
Referring to the drawings, the regenerator 1 compri~es an
inner chamber 2 for storing a heat storage bed and an
,
outer chamber 3 surrounding the inner chamber 2.
The inner chamber 2 is formed within a cylindrical ~hell 4
formed of insulating material of refractory or ceramic
fibre which itself i8 surrounded with clearance by a
cylindrical metal shell 5, the shell 4 serving as an
in3ula~ing lining for the metal shell 5.
The lining rests upon an inwardly directed annular metal
member 6 secured to the lower end of the shell 5 as shown
in the drawings.
The outer chamber 3 is formed by the clearance space
between the metal shell 5 and an outer generally
cylindrical metal shell 7.
The outer shell 7 is provided at its lowermost end with an
inwardly directed annular metal member 8 which is secured
to the shell 7 and which rests upon a platform 9. The
platform 9 supports the regenerator 1 off the ground.
The uppermost end of the outer shell.7 is also provided
with an inwardly directed annular metal member 10 which is
secured to the shell 7 and serves as a support for the
inner metal shell 5. To this end the uppermost end of the
inner metaI shell 5 is provided with an outwardly directed
annular metal member 11 which is secured to the inner
metal shell 5 and restsupon the memberlO.
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In effect therefore, the lining 4 is supported on the
inner shell 5. This in turn is supported on the outer
shell 7 which is supported on the platform 9.
The upper end of the regenerator 1 comprises a cover 12
which restsupon the memberll and the topmost edge of the
lining 4, the cover 12 being suitably secured to these
components. The cover 12 iæ generally circular in shape
and comprises an interior formed of an insulating material
of ceramic or refractory fibre 13 housed in a surrounding
metal shell 14. The cover 12 is provided with a
vertically extending opening 15 which serves in one mode
of operation of the regenerator 1 as an outlet for the
discharge of combustion air preheated in the regenerator
and in the reverse mode of operation as an inlet for waste
gas for heating the regenerator 1 as will be appreciated
by those versed in the art. The cover 12 is also provided
with another opening 16 which serves as an inlet port for
the introduction of heat storage particles into the
chamber 2 formed by the lining 4. It will be seen that
for obvious reasons the openings 15 and 16 lead directly
into the chamber 2. The opening 16 is closed by means of
a releasable sight glass 17 of suitably reinforced and
heat resistant material.
The lowermost end of the chamber 2 i9 closed by a closure
assembly 18 shown in detail in Figure 2 and serving to
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support the bottom end of the heat storage bed. The
assembly 18 comprises an uppermost portion in the form of
a metal cage 19 and a lowermost portion 20 comprising a
cylindrical metal ring 21 seured to the lower edge of the
cage 19, and provided at its lowermo~t end with a circular
flange 22.
The cage 19 comprises a number of spaced metal bars 23
forming a structure in the shape of a champagne glass.
The portions of the bars 23 forming the "steml'24 of the
cage are held together by two spaced metal hoops 25 while
the portions of ~he bars 23 forming the fluted uppermost
part 26 of the cage are held together by a metal hoop 27
suitably shaped for the purpose. The fluted part 26 of
the cage 19 extends inwardly into the lowermost end of the
chamber 2 and terminates close to the inner wall of the
lining 4. An annular plate 28 is secured to the edge of
the fluted part 26 of the cage 19 to serve as a barrier to
the escape of heat storage particles between the cage 19
and the lining 4.
The platform 9 comprises a stage in the form of an
apertured metal plate 29 which i9 supported upon four
metal legs 30 (only two shown in the drawings) of angled
section. The uppermost portion of the metal ring 21 of
the closure assembly 18 is located within the aperture in
the plate 29 and is secured to the plate 29 so that in
effect the closure assembly 18 is supported on the
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platform 9.
The lowermost end of the ring 21 is closed by a releasable
circular plate 31 which is bolted by releasable bolts (not
shown) to the flange 22,
The spaces between ~he bars 23 in the cage 19 permit the
combustion air to enter the chamber 2 and waste gas to
leave it as is conventional.
Referring to Figure 1, the outer metal shell 7 is provided
with two openings 32 and 33 which respectively serve as an
inlet to provide combustion air for preheating in the
chamber 2 and as an outlet for discharging waste gas from
the regenerator after its passage through the chamber 2 to
heat up or reheat the heat storage bed. It will be
appreciated that when the inlet 32 is supplying the
combustion air the outlet 33 is closed and similarly when
the outlet 33 is discharging waste gas the inlet 32 is
closed. The inlet and outlet are respectively formed by
two externally threaded stub pipes 34 and 35 secured to
the shell 7. The inlet pipe 34 may be connected to a
suitable source of combustion air while the outlet pipe 35
may be connected to a flue.
The opening 15 in the cover 12 communicates with a
regenerative burner 36 of the type which is disclosed in
British Patent No. 2136 553B, published 12 February, 1986. To
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this end the cover 12 i8 provided with an apertured metal
plate 37 with the portion of the cover 12 forming the
opening 13 projecting through the aperture in the plate
37. This plate 37 is secured to a plate 38 forming a
flange in a corresponding opening 39 in the burner 36
The opening 39 in the hurner 36 serves in one mode of
operation of the regenerator 1 as an outlet for
discharging waste gas which has entered the burner 36
through its forward end 40 from a furnace or like
enclosure (not shown) and in the reverse mode of operation
as an inlet for receiving from the regenerator 1 the
combustion air preheated in the regenerator 1. The burner
36 is provided with a fuel gas inlet 41 by means of which
the fuel gas can be introduced into the burner 36 for
mixing with the preheated combustion air in the burner 36
before discharge as combusted gas from the forward end 40
of the burner 36 into the furnace or enclosure to which
the burner 36 is connected. The burner 36 is also
provided with a pilot air inlet 42 for purposes which are
fully described in our British Patent No. 2136 553B
together with a spark probe 43 for ignition
purposes and flame detection sight ports 44.
The heat storage bed itself comprises small discrete
particles of any suitable shape and insulating material.
In Figure 1 the bed particles are in the form of small
ceramic spheres 45. These are introduced into the chamber
2 through the inlet port 16 at the top of the regenerator
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1, the sight glass 17 being removed for the purpose and
then replaced after sufficient particle 8 have been
introduced. Contaminated particles may be run out through
the closure assembly 18 at the bot~om of the regenerator 1
by removing the plate 31, the plate 31 being replaced
before fresh particles are introduced into the chamber 2.
In this way if the heat storage bed becomes blocked due to
the build up of charge contaminants carried by the waste
gas, the bèd can be removed and replaced with fresh
material.
Depending on the type and amount of contaminant carried
over in the waste gas, this operation can be carried out
intermittently or continuously. The heat storage particles
can also in some circumstances be cleaned and re-used. By
automating this discharge\recharge process there is no
need for any manual cleaning of the regenerator as is
commonly required when conventional regenerators are used.
In addition the discharge\recharge process can be carried
out whilst the charge is being heated and therefore
maintenance downtime is reduced.
The inner shell 5 and lining 4 are air cooled during the
air preheating cycle and this is beneficial in extending
the overall life of the lining ~.
