Note: Descriptions are shown in the official language in which they were submitted.
CA 02545949 2006-05-12
WO 20051047778 PCT/EP2004I011484
A refri eratin~ apparatus, in particular for the cooling of
refri eratin~ ss~aces
The present invention relates to a refrigerating apparatus, in particular for
the cooling of refrigerating spaces. comprising two alternately activatable
heat exchangers, in particular evaporators or coolers of a coolant circuit,
and at least one fan to blow gas, in particular air, through the heat
exchanger.
A refrigerating apparatus of the initially named kind is known from DE
197 09 176 C2. With this refrigerating apparatus, the two alternately
activatable heat exchangers made with lamellae are arranged next to one
another or over one another and are flowed through by the same flow of
the medium to be cooled. This means that the two heat exchangers are
each only charged by half of the flow. To achieve a desired charge with a
medium flow, the total flow must therefore be selected to be twice as large.
The fan must be made correspondingly large, whereby the costs and the
space requirements are increased.
It is the underlying object of the invention to provide a refrigerating
apparatus of the initially named kind which does not have these
disadvantages. The refrigerating apparatus should in particular be cost
favorable and space saving.
This object is satisfied in that the heat exchangers are arranged such that
they can each be flowed through by the total gas flow of the fan at least on
activation.
By the arrangement of the heat exchangers such that they can each be
flowed through by the total gas flow of the fan, the required total gas flow
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can be reduced to approximately half with respect to the known
apparatus. The fan must accordingly be dimensioned smaller, whereby
costs and space are saved.
A flowing through of both heat exchangers by the total gas flow can in
particular be achieved in that the two heat exchangers are arranged
behind one another in the direction of flow. In this process, both heat
exchangers can be arranged on the same side of the fan. Both heat
exchangers are thereby automatically charged with the total gas flow,
irrespective of the direction in which the fan blows.
Another arrangement consists of a first heat exchanger being arranged
before the fan or fans in the direction of flow and a second heat exchanger
being arranged behind the fan or fans in the direction of flow. The two
heat exchangers can thereby protect the fan from external influences.
A design is particularly cost favorable in which the heat exchangers are
arranged freely in front of or behind the fan or fans. No additional
components are thereby necessary and conventional heat exchangers can
be used. Special products as with the initially named refrigerating
apparatus are not necessary.
Gas conducting passages can, however, also be arranged between the fan
or fans and the heat exchangers. A plurality of advantages hereby result.
The heat exchangers and the fan can inter alia be arranged spaced from
one another. In addition, pressure measuring devices such as pressure
gages, filters or attenuators can be arranged in the gas conducting
passages.
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In accordance with a further embodiment of the invention, the fan or fans
and the heat exchangers are also arranged in closed gas conductors. The
flow generated by the fan can thereby be fully utilized and a good flow
guidance can be achieved.
It is particularly preferred for the fan or fans and the heat exchangers to
be arranged in a common housing. This is space saving, on the one hand,
and also effects a goad protection of the fan or fans by the heat
exchangers exchanged in front and/or behind them:
Gas conducting passages can preferably be connectable to the housing at
least at the gas outlet side. This advantageously permits the remote
installation of the housing from the location to be cooled, for example in
the false ceiling of a refrigerating space or completely outside a building
surrounding the refrigerating space.
In accordance with a particular embodiment of the invention, a fan with a
reversible blowing direction is provided. By reversing the blowing direction
of the fan, the direction of flow of the gas through the heat exchangers
arranged in front of or behind the fan can be reversed, in particular such
that the gas is sucked in by the respectively non-active heat exchanger
and blown out by the respectively active heat exchanger. The non-active
heat exchanger is thus flowed through by the gas to be cooled and is
heated by it, which can advantageously be used for defrosting with
evaporators of a coolant circuit when the temperature of the gas to be
cooled is above freezing point. Subsequently, the gas thereby already
cooled passes through the activated second heat exchanger, with it being
further cooled in the desired manner.
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One heat exchanger can thus always be defrosted and one used for
cooling by an alternate activation of the two heat exchangers and a
corresponding reversal of the blowing direction of the fan. This also has
the advantage that the blowing out direction of the unit changes cyclically,
whereby a better distribution of the cooled gas in the refrigerating space
can be achieved. If, in contrast, a blowing out should always only be
desired in one direction, this can be achieved by a suitable arrangement of
gas conducting passages and valves in front of the outlets or inlets of the
refrigerating apparatus.
In accordance with another embodiment, the different throughflow
direction of the heat exchangers is realized by valve-controlled fluid
guides.
With this embodiment, the gas can also be alternately sucked in by the
one heat exchanger and blown out by the other heat exchanger, with the
one heat exchanger respectively being inactive and optionally defrosted,
whereas the other heat exchanger is activated for cooling. A reversal of the
blowing direction is not necessary with this arrangement. A further
advantage consists of the fact that the fan power can be optimized for the
only blowing direction of the fan.
In accordance with a special embodiment of the invention, a fan is
provided whose blowing side can alternately be connected via switch-over
valves and corresponding gas conducting passages to the first heat
exchanger or the second heat exchanger and its suction side to the
respectively other heat exchanger. With this variant, the fan is therefore
arranged between the two heat exchangers.
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In accordance with another special embodiment, a fan is provided whose
suction side is connected to the entry opening of the apparatus and whose
blowing side is alternately connected to the first heat exchanger or to the
second heat exchanger, with the respectively other heat exchanger being
5 connected to the one heat exchanger, on the one hand, and to the outlet
opening of the apparatus, on the other hand. In this variant, both heat
exchangers are accordingly arranged in front of the fan or both heat
exchangers are arranged behind the fan in the direction of flow.
In accordance with yet another special embodiment of the invention, two
fans are provided which are arranged in opposite senses and parallel to
one another and are each connected to the two heat exchangers via gas
conducting passages and can be activated alternately. It can again also
thereby be achieved that the gas to be cooled is alternately sucked in by
the one heat exchanger and blown out by the other heat exchanger. In
this process, one fan is active and the other fan is inactive respectively.
The advantage is also present here that the fan power can be optimized for
the only direction of flow.
The respectively non-active branch of this arrangement can preferably be
closed via a valve. A false flow through the non-active branch can thereby
be avoided.
In accordance with a particularly preferred embodiment of the invention,
the inlet opening and the outlet opening of the apparatus are formed in
each case by the same opening irrespective of the throughflow direction of
the heat exchangers. The advantage thereby results that a filter attached
behind the inlet opening is always flowed through in the same direction.
No exchangeable filters therefore have to be provided, which permits a
particularly good sealing of the filters. False air can hereby largely be
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avoided so that a high filter performance up to clean room engineering can
be ensured.
It is likewise preferred for the inlet opening and the outlet opening of the
housing always to be arranged at the same side of the apparatus, in
particular next to one another. A particularly compact design of the
apparatus can thereby be achieved, whereby the space requirements can
advantageously be reduced.
A further reduction in the space requirements can be achieved in that the
fluid guides extend in different planes at least sectionally, in particular
above one another and beneath one another, in accordance with a further
embodiment of the invention. In addition, this variant is particularly
advantageous when the inlet opening and the outlet opening are arranged
on the same side of the apparatus.
It is furthermore advantageous for the diameter of the fluid guides to differ
in different sections. The diameter can in particular be larger in the region
of the heat exchangers than in front or behind them, for example in a ratio
of approximately 2 : 1. The construction size can thus also be further
reduced, without the performance capability of the apparatus being
noticeably restricted since the cross-section can be kept advantageously
large in the region of the heat exchangers and the reduced cross-section in
another respect means hardly any impairment.
Axial fans can be used as fans in the refrigerating apparatus in
accordance with the invention. However, radial fans can preferably also be
used in the refrigerating apparatus in accordance with the invention. The
latter have the advantage of a considerably higher pressing, which in
particular comes into effect with the use of gas conducting passages.
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The use of radial fans also permits the use of filters for the gas to be
cooled. They can in particular be arranged in the gas conducting passages
and jor in the fan housing. High hygiene demands can be satisfied by the
use of filters.
In particular at least one rotary filter can be provided as the filter which
is
rotatable in dependence on the direction of flow of the gas. In this manner,
the filter is always charged in the same direction by the gas flow. A
blowing out of filtered particles again can thereby be avoided.
In accordance with a further embodiment of the invention, at least one roll
filter is provided. The latter can, for example, be made as a disposable
filter and can be further rotated accordingly on every reversal of the
direction of flow.
In accordance with another embodiment of the invention, the filter roll
can, however, also be made to be movable to and fro in a cyclic manner in
dependence on the direction of flow of the gas. A respective section of the
filter roll is thereby always charged with the gas flow in the same direction
so that the blowing out of particles again can also be avoided here. On the
reaching of a specific degree of load of the filter, the roll can then be
rotated further by twice the filter length so that two new sections of the
roll filter can be used alternately.
At least one pressure measuring device, in particular a pressure gage, can
be arranged in the gas conducting passages and/or in the fan housing. It
can be used both for the determination of the degree of icing of the heat
exchangers and for the determination of the necessity of a change of filter.
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A change of filter or a further rotation of a roll filter can, however, also
be
triggered or indicated at the end of a predetermined or predeterminable
time, for which purpose corresponding means are provided in accordance
with a further embodiment of the invention. A pressure measuring device
can thereby be saved. Good results can nevertheless be achieved on the
basis of experience values.
The reversal of the direction of flow through the two heat exchangers can
also take place in dependence on time, for which purpose suitable means
are likewise preferably provided. Good results can also thereby be
achieved on the basis of experience values and corresponding measuring
devices such as pressure measuring devices for the detection of the degree
of icing of the heat exchangers can be saved.
In accordance with a further embodiment of the invention, means for
sterilization are provided in the gas conducting passages and/or in the fan
housing, in particular in the region of the outlet opening. Hygienic
demands can also thereby be satisfied, with the sterilization being
particularly effective in the outlet region.
Means for LJV irradiation or ionization can preferably be provided for the
sterilization. Alternatively or additionally, it is also possible to provide
means for the injection of disinfectants, for example fruit acid. Both
measures are well suited for sterilization.
The two heat exchangers are generally operated alternately. In accordance
with an embodiment of the invention, however, an overlapping operation
is also possible by a corresponding control for the activation of the heat
exchangers. An increased refrigerating capacity can be made available in
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the short term by such a control. The air humidity can additionally
thereby be regulated.
Furthermore, sound attenuation devices in the fan housing or in the gas
guides are advantageous. The noise radiation of the apparatus can
thereby be reduced.
The speed of rotation of the fan or fans can advantageously be regulated
for the regulation of the capacity of the refrigerating apparatus in
accordance with a further embodiment.
An advantageous design results when the housing has a plurality of
chambers. It is advantageous for service and repair purposes in this
process if the chambers are each accessible via their own access opening,
in particular a door.
It is furthermore advantageous for each chamber to have its own
condensate drain. Service and repair measures can also be simplified in
that a lighting device is provided in the housing.
Non-restricting embodiments of the invention are shown in the drawing
and will be described in the following. There are shown, schematically in
each case:
Fig. 1 a block diagram of a first variant of the refrigerating
apparatus in accordance with the invention;
Fig. 2 a representation in accordance with Fig. 1 of a second variant;
Fig. 3 a representation in accordance with Fig. 1 of a third variant;
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Fig. 4 an upper view of a fourth variant of the refrigerating
apparatus in accordance with the invention;
5 Fig. 5 a perspective view of the variant of Fig. 4 from a first direction
of view; and
Fig. 6 a perspective view of the same apparatus from a second
direction of view.
Fig. 1 shows a fan 1, two heat exchangers 2 arranged at both sides of the
fan 1 as well as two filters 3 arranged in each case on the side of the two
heat exchangers 2 remote from the fan 1. Gas guides 4 are present
between the fan 1 and the heat exchangers 2 and the filters 3> with these
being able to consist of passages or lines. The fan 1 and the heat
exchangers 2 as well as preferably also the filters 3 can, however, also be
arranged in a common housing which then ensures the schematically
shown gas guidance between the named components.
In addition, two pressure gages 5 are shown via which the pressure can be
detected on both sides of the fan 1. A pressure gage 5 of this type can be
arranged both in the region of the filters 3, as shown, to be able to draw a
conclusion on the degree of load of the filters 3, and in the region of the
heat exchangers 2 to be able to draw a conclusion on their degree of icing.
To be able to detect both, a plurality of pressure gages 5 can also be
provided on each side.
The fan 1 is made as a radial blower whose direction of rotation can be
reversed. In this manner, a gas flow can be generated both in the direction
of the arrow 6 and in the reverse direction in accordance with arrow 7.
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The switch-over can take place in dependence on the degree of icing of the
heat exchangers 2 or in dependence on time. A corresponding control is
provided, but not shown.
The filters 3 can be made as rotary filters, in particular as bag filters
rotatable around 180°. The rotary position can be set according to the
blowing direction of the fan 1 via a suitable control so that the filters are
always charged by the gas flow 6 or 7 in the same direction and the
particles absorbed by the filters 3 are not blown out again when the
direction of rotation of the fan 1 reverses. The filter 3 on the outflow side
could, however, also simply be moved out of the flow since it is often
sufficient for the filter 3 on the suction side to be active.
Roll filters with which filter material can be wound off a roll can also be
used instead of bag filters. If the roll filter is made as a disposable
filter, it
is respectively wound off the roll by a corresponding length on the reversal
of direction of the fan 1. However, a multifilter can also be used with
which the control winds the filter on and off cyclically so that always the
same section of the filter is active in the one and the other blowing
direction 6, 7 of the fan 1. The control can furthermore be made such that
on a specific degree of loading of the filter the roll is further rotated so
far
that two new sections are available for the rolling onto and off the roll.
The necessity of a change of filter or of a further rotation of a roll filter
can
be detected via a suitable control in dependence on the pressure. The
control can indicated this and/or initiate an automatic change or an
automatic further rotation of the filter.
The necessity of a filter change can, however, also be detected by the
passing of time instead of via the pressure. The time span in particular
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results from experience values and can be preset. The time span can,
however, also be changeable and be predetermined by the user.
The heat exchangers 2 can be made with lamellae as is described, for
example, in DE 19709 176 C2. In another respect, conventional heat
exchangers can, however, also be used such as are also used for simple
fans blowing only in one direction. Conventional fans of this type can also
be used for the fan 1.
In the variant shown in Fig. 2, the direction of rotation of the fan 1 is not
reversible. Instead, the fan 1 is respectively connected to the two heat
exchangers 2 via two alternative paths 4a, 4b and 4c, 4d. In each of these
four sections 4a, 4b, 4c, 4d, a closing valve 8 is arranged which is opened
or closed depending on the desired direction of flow of the gas flow 6 or 7.
To effect a flow in accordance with the arrows 6, the valves 8 in the
sections 4a and 4d are open and those in sections 4b and 4c are closed.
Accordingly, to effect a flow in accordance with the arrows 7, the valves 8
in the sections 4b and 4c are open and those in sections 4a and 4d are
closed. The fan 1 is here also preferably made as a radial blower, with it
now, however, being able to be optimized better due to the single direction
of rotation. In other respects, the design of this variant can be identical to
the one previously described. The mode of operation is also identical with
the exception of the switching over of the valves 8.
In the variant shown in Fig. 3, two fans la and lb are provided which are
arranged parallel to one another and with opposite directions of rotation
in a respective part section 4e, 4f of the gas guide 4. The one fan la or the
other fan lb is switched on in dependence on the desired direction of flow
6 or 7. A flow is in particular generated in the direction of arrow 6 by
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switching on the fan 1 a and closing the section 4f and a flow in the
direction of arrow 7 by switching on the fan lb and closing the section 4e.
The respective section 4e or 4f with the non-active fan la or lb is closed
via closing valves 9 in the two sections 4e and 4f to avoid a false flow.
The two fans la and lb are in turn preferably made as radial fans and are
optimized for their respective direction of flow. In other respects, the
apparatus can also be made in the same manner as with variant 1 here.
The operating mode is also identical to that of variant 1 with the exception
of the alternate activation of the two fans la and lb and the closing of the
respectively other section 4f or 4e.
The variant shown in Figs. 4 to 6 includes a housing 10 with an inlet
opening 11 and an outlet opening 12. A filter 3 is arranged behind the
inlet opening 11 and behind it a fan 1 not reversible in its direction of
rotation. The suction side of the fan 1 faces the inlet opening 11 of the
housing 10. The blowing side of the housing 1 is adjoined by a valve 13
and behind this the two heat exchangers 2.
The housing 10 is divided by a partition wall 14 into two regions 15 and
16 which are in turn divided into a plurality of chambers 18 by partition
walls 17. The filter 3 is arranged in a first chamber 18' behind the inlet
opening 11 of the housing 10. It is followed by a chamber 182 which is
separated from the first chamber by a partition wall 17'. The partition wall
17' has a passage opening 19 to which the suction side of the fan 1 is
connected.
The chamber 18z with the fan 1 is bounded on the other side by a
partition wall 172 in which the valve 13 is provided. As can in particular be
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recognized in Fig. 5, the height of the valve 13 amounts approximately to
half the height of the partition wall 17z.
The partition wall 172 bounds a further chamber 183 with the first heat
exchanger 2'; the first heat exchanger 2' a chamber 184 with the second
heat exchanger 22; and the second heat exchanger 22 a further chamber
185 with the housing 10. All chambers 18' to 185 are located in the first
housing section 15.
As can in particular be recognized in Fig. 6, a chamber 186 and a chamber
18' are formed in the second housing section 16 by a two-fold angled
partition wall 173. The chamber 186 is connected to the chamber 185 via
an opening 20. A further connection of the chamber 186 is present via a
valve 21 to the chamber 182 in which the fan 1 is located. The chamber
18' is connected to the chamber 183 via a further valve 22 and to the
chamber 186 via a further valve 26.
The angled partition wall 173 has a first vertical section 23 which is
connected to the upper side of the housing 10, a horizontal section 24
adjoining it and a second vertical section 25 which adjoins the latter and
is connected to the base of the housing 10. The height h, of the second
vertical section is approximately half the size of the height hz of the first
vertical section. In addition, the further valve 26 is provided in the second
vertical section 25.
All the chambers 18 of the housing 10 are provided with their own
condensate drain as is indicated by jagged arrows 27. In addition, the
chambers are accessible, in particular for maintenance and repair work,
via doors 28. Furthermore a LJV radiation device 29 is provided in the
chamber 186 and the medium guided through the apparatus can be
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sterilized by it. Finally, a lighting can be provided in the housing 10.
In the variant shown in Figs. 4 to 6, the inlet opening is always formed
independently of the throughflow direction of the two heat exchangers 2'
5 and 2~ by the opening 11 and the outlet opening is always formed by the
opening 12 of the housing 10. To nevertheless permit a changing
throughflow of the two heat exchangers 21 and 22, the valves 17, 21, 22
and 26 are provided. The valves 17 and 26 are open, the valves 21 and 22
closed, in contrast, for the throughflow of the apparatus in the first
10 direction marked by the arrow 6. The gas flow sucked in through the fan 1
moves from the inlet opening 11 via the filter 3 into the chamber 18' and
from there into the chamber 182. Then the gas flow moves through the
valve 13 into the chamber 183, flows through the first heat exchanger 2',
which is inactive in this case and is defrosted by the warm gas flow, then
15 into the chamber 185, then through the active heat exchanger 22 by which
the gas flow is cooled and then into the chamber 185. From there, the gas
flow moves via the opening 20 in the wall 14 into the chamber 186 in
which the gas flow is sterilized by the LJV radiation device 29. The gas flow
then flows through the valve 26> moves into the chamber 18' and moves
from there via the outlet opening 12 out of the housing 10 of the
apparatus.
On the reverse operation of the apparatus in accordance with arrow 7, the
valves 17 and 26 are closed, whereas the valves 21 and 22 are open. The
gas flow sucked in by the fan 1 now no longer moves from the chamber
182 into the chamber 183 since the valve 13 is closed, but rather via the
valve 21 into the chamber 186. From there, the gas flows on through the
opening 20 in the wall 14 into the chamber 185, flows through the second,
now inactive heat exchanger 22, with this being defrosted, further into the
chamber 184, then through the first, now active heat exchanger 2' which
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cools the gas flow and then into the chamber 183. Since the valve 13 is
closed, the gas flow moves from the chamber 183 via the valve 22 into the
chamber 18' and flows out from there via the outlet opening 12 of the
housing 10. The gas is also sterilized by the UV radiation device 29 in the
chamber 186 in this operating direction. Instead of the arrangement of the
radiation device in chamber 186, it can also be arranged in chamber 18',
that is in the region of the outlet opening 12.
As can be recognized, the two heat exchangers 21 and 22 can selectively be
flowed through in the one or the other direction 6, 7 in accordance with
the operating mode described. A large cross-section of the heat exchangers
and, on the other hand, a relatively low housing size overall is realized by
the ratio of the housing section 15 to the housing section 16 of
approximately 2 : 1. The cross-section changes thereby occurnng have no
disadvantageous influence on the flow.
In all the variants shown, both heat exchangers 2, which can in particular
be the evaporator or cooler of a coolant circuit, are flowed through by the
total gas flow of the fan 1 or of the fans la, lb. This means that gas is
sucked in by the one heat exchanger 2, which is then not activated, and is
blown out by the other heat exchanger 2, which is activated. If the first
heat exchanger 2 is iced, the sucked in gas is already cooled. With gas
having a temperature above freezing point, the first heat exchanger 2 is
thereby defrosted without any electrical or other defrosting equipment
being necessary. The gas is further cooled in the desired manner in the
active, second heat exchanger.
After reaching a specific degree of icing of the second heat exchanger 2 or
after a predetermined extent of time, the flow direction is switched over in
that, in the case of the variant of Fig. 1, the direction of rotation of the
fan
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1 is switched over. In the case of the variant of Fig. 2, the valves 8 are
switched over for this purpose from their open position into their closed
position and from their closed position into their open position. And in the
case of the variant of Fig. 3, when the fan la was first switched on, it is
switched off and the other fan lb is switched on and the closed valve 9 is
opened and the open valve 9 is closed. If, on the other hand, the fan lb
was switched on, the switch-over takes place in reverse accordingly. The
switching over in the variant of Figs. 4 to 6 has already been described
above.
In all cases, an overlapping operation is also possible in which both heat
exchangers 2 are active for a specific period of time. The refrigerating
capacity can thereby be increased in the short term, on the one hand, and
the humidity content of the gas can thereby be regulated, on the other
hand.
Filters 3, gas conducting passages 4 and also noise attenuation devices
can be used due to the use of a radial fan with which a much higher
pressing can be realized than with an axial fan. The noise of the
refrigerating device can thereby be advantageously reduced.
In addition, means can be provided in the fan housing for sterilization,
such as LJV radiation, and means for the injection of disinfectant, such as
fruit acid.
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Reference numeral list
1 fan
la, lb fan
2, 2', Z heat exchangers
3 filter
4 gas guide
4a - 4f section of 4
5 pressure gage
6 direction of flow
7 direction of flow
8 valve
9 valve
10 housing
11 inlet opening
12 outlet opening
13 valve
14 wall
15 housing section
16 housing section
17' - 173 partition wall
18' - 18' chamber
19 opening
20 opening
21 valve
22 valve
23 vertical section
24 horizontal section
25 vertical section
26 valve
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2~ condensate drain
28 door
h, height of 25
h2 height of 23
