EVAPORATOR

EVAPORATEUR

English Abstract

An evaporator which encloses a refrigerating chamber (4) of a compressor-type
refrigeration unit operated with hydrocarbons and is enclosed on the outside by a heat
insulating layer (3) and is provided with a meander-shaped refrigerant duct (8) with a
refrigerant inlet (9) and a refrigerant outlet (10) between two metal sheets of the
evaporator wall, i.e. an inner and an outer metal sheet (5 and 6), with the two metal
sheets (5, 6) mutually having a fixed metallic connection (11) in form of welding or
soldering next to and between the refrigerant duct segments, with an additional inner-wall
sheet (7) being provided on the refrigerating chamber side which forms the inner wall of
the evaporator wall of the refrigerating chamber, which is provided with a metal surface
contact with the inner metal sheet and which within the surface contact zone between the
inner-wall sheet (7) and the inner metal sheet (5) is provided with connecting surfaces
(13, 13a) of the welded or soldered type.

French Abstract

Evaporateur pour réfrigérateur à compression, dont la paroi, composée d'une tôle métallique intérieure (5) et d'une tôle métallique extérieure (6), présente un canal à réfrigérant (8) à méandres, et qui est bien protégé contre une fuite de réfrigérant par une tôle supplémentaire de paroi intérieure (7) et, le cas échéant, par une tôle supplémentaire de paroi extérieure (15). Tous les éléments de la paroi de l'évaporateur, à savoir la tôle de paroi intérieure (7), la tôle métallique intérieure (5), la tôle métallique extérieure (6) et, le cas échéant, la tôle de paroi extérieure (15) sont soudés ou brasés entre eux.

Claims

o 5
CLAIMS
1. An evaporator which encloses a refrigerating chamber (4) of a compressor-typerefrigeration unit operated with hydrocarbons and is enclosed on the outside
by a heat insulating layer (3) and is provided with a meander-shaped refrigerantduct (8) with a refrigerant inlet (9) and a refrigerant outlet (10) between two
metal sheets of the evaporator wall, i.e. an inner and an outer metal sheet (5
and 6), with the two metal sheets (5, 6) mutually having a fixed metallic
connection (11) in form of welding or soldering next to and between the
refrigerant duct segments, with an additional inner-wall sheet (7) being
provided on the refrigerating chamber side which forms the inner wall of the
evaporator wall of the refrigerating chamber, which is provided with a metal
surface contact with the inner metal sheet and which within the surface
contact zone between the inner-wall sheet (7) and the inner metal sheet (5) is
provided with connecting surfaces (13, 13a) of the welded or soldered type,
characterized in that between adjacent connecting surfaces (13, 13a) there are
thin separating layers (14) between the inner-wall sheet (7) and the inner metalsheet (5) which have a meander-shaped course which is adapted to the
meander-shaped course of the refrigerant duct (8), but are each wider than the
refrigerant duct (8).
2. An evaporator as claimed in claim 1, characterized in that the connecting
surfaces (13) between the inner-wall sheet (7) and the inner metal sheet (5) arelimited to strip-like or insular surface segments which are distributed over theevaporator wall.

3. An evaporator as claimed in one of the claims 1 or 2, characterized in that on
the insulating layer side there is provided an additional outer-wall sheet (15)
which forms the outer wall of the evaporator wall and has metallic surface
contact with the outer metal sheet (6) and in which within the surface contact
zone between the outer-wall sheet (15) and the outer metal sheet (6) there are
provided connecting surfaces (17) of the welder or soldered type, characterized
in that between adjacent outer connecting surfaces (17) there are provided thin
outer separating layers (16) between the outer-wall sheet (15) and the outer
metal sheet (6) which have a meander-shaped course adapted to the meander-
shaped course of the refrigerant duct (8), but are each wider than said
refrigerant duct (8).
4. An evaporator as claimed in claim 3, characterized in that the outer connecting
surfaces (17) between the outer-wall sheet (15) and the outer metal sheet (6)
are limited to strip-like or insular surface segments which are distributed overthe evaporator wall (2).
5. An evaporator as claimed in one of the claims 1 or 2, in which the fixed
metallic connection between the inner metal sheet (5) and the outer metal
sheet (6) is manufactured by welding under application of roll-welding
according to the roll-bonding method and the refrigerant duct (8) is
manufactured by inflating non-welded zones prior to the shaping of the
evaporator, characterized in that the connecting surfaces (13, 13a) between
the inner-wall sheet (7) and the inner metal sheet (5) are produced in one pass
with the roll-welding of inner metal sheet (5) and outer metal sheet (6).
6. An evaporator as claimed in claim 5, characterized in that the connecting
surfaces (17) between the outer-

wall sheet (15) and the outer metal sheet (6) are produced in one pass with the
roll-welding of inner and outer metal sheet (5 and 6).

Description

PCr~EP/94/03so3 21 76 705
F.~ApORATOR
The in~rention relate~ to an evaporator which enclose~ a
xefrige~ating c~amber o~ a compres6~r-t~pe refrigeratlon
unit opcrated wich ~ydrocarbon6 a~ refrigerant and which i9
enclosed on the out~ide by a heat in~ulating layer and is
pro~rided between two me~al sheets of the e~aporator ~all,
i . e . an inner and an outer metal ~heet, with a meander-
shaped refrigerant du~t with a refrigerant inlet and a
re~rigexant outlet, wi~h the two metal sheet~ mutually
ha~ing a f ixed metallic connection in fonn of welding or
~olderi~g next to and bet~ee~ the refrigerant duct
seg~ents, with an additional innex-wall ~heet being
pro~rided on the re~rigera~t chamber side ~hich forms the
in~e~- wall of the evaporator wall o~ the refrigeran~
char,~er, which i8 pro~ided ~ith a metal su~ace ~t~çt
wi~h the inner metal ~heet and which wi~hin the ~urface
con~act zone between the inner-wall shee~ and the inner
metal ~heet is pro~ided with connecting ~ur~ace~ of th~
welded or soldered type.
~n e~aporator equlpped with the aforemen~ione~ fea~res is
~no.nl. from DE-A-l 426 923. This known e~aporator, howe;er,
is ~ot pro~ided ~ith any addi~ional protectlon agai~-st
lea-:age~ . With respect to heat PYch~ngers~ in partlc-~lar
~uch o~ the "roll ~o~; ngl~ type, additional plate~ ~o:~ rhe
protec~ion again~t leakages were kno~n (~S-A-4 678 027 and
EP-~-0 206 416).
In order to form a refrige~ating cham~er, evaporators ar~
regularly shaped from respecti~e plane evaporaror bl~.~k~
~hich - ~en ~haped - fonm ac least the ~our wall~ o~ the
rerigerating ~mhe~, e.g. a ~reezer ~t~on, and
freguently also the rear wall. Such evaporator blank~ and
their production according to the ~o-called roll-bo~ g
;

21 76705
~ethod are ~hown in D~-C 1 552 044 by way o~ example.
Dur~ng ~he roll-bonding proce6~, where the two layers of
the blank are mutually joined by r~ welding with the
~tretchlng of the s~bst~ate, preci~ely delimited areas
which form the uture cource o~ the re~rigerant duct are
en~ured by separating layer~ ~ade ~rom weld-ob~tructing
material. This measure is de~cribed by way of exa~ple in
DE-C 1 920 424.
Tn the past only hydrocarbon was u~ed as a refri~erant
(CFCs), wherea~ newer refrigeratin~ ~ystem~ use
hydrocarbon~ Fuch as isobutane, i~opropane or propane-
butane. The6e hydrocarbon~ form an inflammable mixture with
air, so that increasingly ex~?lo~io~-protected elect~ical
de~ice~ are used in the zone o~ the refrigerating ~h~
ae a preca~tionary mea~ure. In addi~ion, ~ n~ ar~ made
~or additional measures to pre~ent refrigerant leakage6, in
partlcula~ towarda the re~rigerating r~mh~
It i~ the ob;ect in accordance with the invention to
provide an e~aporator of the kind mentioned abo~e ln such a
way that the danger of a refrlgerant leaka~e w~thout any
sub3tantial lo~s in the refrigerating ou~put o~ the
evaporator i~ reduced.
It i~ therefore p~oposed in accordance with the invention
that between ad~ acent connecting surfaces there are t~in
separating layers between the inner-~all ~heet and the
inn&X ~etal cheet which ha~e a m~ shaped course which
1~ adapted ro the ~n~ r-sh~ couree o~ the refrigerant
duc~, ~ut a~e each wider t~an the re~rigerant duct.
Reference i~ hereby made eo embodiments of the invention
pursuant to ~he subclalms. Thu~ a ~lrst em~o~;mont pro~ide~
that the connect~g sur~ace~ between the inner-wall ~heet
and the inner meeal ~hee~ are li~lted to se~ip-like or

3 2~ 76705
in~ular ~urface segments w~ic~ are dlstr~buted o~r the
evaporator wall.
F~rther e~bodiments of the l~vent~on al~o provlde
additional oecurity on the out~ide in Buch a way that on
the slde of the insulating layer there is pro~iaed an
additional outer-~rall sheet which forrns the ou~er wall of
the e~aporator wall and has metallic surface contact wich
the outer ~etal s~eet, ~nd that within the s~r~ace contact
zone between the outer-wall ~heet a~d the outer metal sh~et
there are connecting 8urfa~e6 of the soldered or welaed
t~p~. Between adjacen~ outer connecting 6urfaces there are
pro~ided thin oute~ separatlng layers betwee~ the oute~-
~all 6heet and the outer metal ~heet which ha~e a meander-
~haped cour~e adapted to the meAn~er-~haped cour3e of the
re~rigerant d~ct, ~ut are each wider than said ~e~rige~ant
duct.
~ Sl~ilaz to the inner protection it i~ proYided
advantageou~ly in this respect that the outex connecti~g
~ur~ace~ between the outer-wall sheet and the outer metal
sheet are limi~ed to strip~ e or insular surface ~egme~ts
~hich are distributed o~r the ~a~otator wall.
~n an e~aporator where the fixed metallic co~nec~ion
between the inner metal sheet and the outer metal sheet i~
manu~actured by welding under application of roll-weldlng
according to the roll _h~Ai ~ method and the refrigerant
duct i~ manufactured by infla~ing non-welded zoneQ prior to
the ~haping of ~he eva~o~dtor~ the CQ~e~ting s~rfaces
between the inner wall and the lnner ~etal sheet or ~e~een
the o~t~r wall and the outer metal sheet are produced in
one pa~s with the roll-~elding of in~er and outer ~et~l
sheet.
The object ~s achieved by the in~ention in a simple way.
~xcept ~or the use of further ~heet~ for th~ inner-wall

4 21 76705
~ sheet and, optionally, the outer-wall shee~c the invention
doe~ not rec~uire any ~dditional manufacturing wor~c, because
t~e welding of the three or four laye~, for example, car~
~e carried out according to the roll-horl~i ng met:hod in one
paE3~ and with the exi~ting eq~ipment.
The in~rention i~ now explained below by ref erence to the
embo~;ment~ shown in the Pigures, which ~how in a ~chematic
representation a3 ~ollow~3:
Fig 1 an evapora~or of a co~pressor-ty~e refrigeration
Unit:
Fig. 2 a ~;ectional view of an evaporator ~all;
Fig . ~ a top view o~ an evaporator wall i
Fig. 4 a gec'clonal view o~ a~ e~d~o~ c.tor wall in a
perepecti~re ~iew.
Fig. 1 show~ an evaporator 1 wi~ h the ~our evaporator walle
2 which are formed from a respecti~rely large e~raporato~
~lank by the ben~in~ thereo~. The ev~poL~tor is enclosed on
the outside by a heat insulating layer 3 which is only
showr~ in a sectional view, The re~rigerating ch~rnhe~ 4 iB
limited at t~e rear regmlarly }~y a rear wall ~not
designated in cloeer detail).
The evaporator wall 2 is shown in a pa~tly sectional ~iew,
with its ar~angement ~eing more clearly visible in ~ig. 2.
I t con~ists of an inner metal ~heet 5 and an outer ~etal
sheet 6 and an inner-wall ~heet 7. 'rhe re~igerant duct ~
i6 located beeween the inner metal sheet 5 and the outer
metal ~heet 6. The re~rigeran~ duct ~ 1~ p~o~ide~ with a
re~igerant inlet 9 and a refrigerant ou~let 10, a~ i6
sho~ in Fig. 1.

5 21 76705
~ig~ 2 6how~ moreo~er that ~he inner metal sheet 5 iB
pro~ided with a ~ixed metallic connectio~ 11 ~ith the outer
metal aheet 6 on either side of the refrigerant duct ~,
~hich has the form of a welding here. For the sake o~
improved clarity it ii outlined o~erproportionally. In the
refrigerant duct ~er ~e the aeparating central layer 12 i~
al90 Bhown overp~o~ ionally, which layer enabled the
inflation o~ the ~efrigerant duct 8.
~etween the inner me~cal ~he~t 5 ar~d the inner-wall ~heet 7
there are o~erproportlonally repreeented connectlng
surfaces 13, 13a, which ar~ of the welded type ~ere. ~ thl~
separating layer 14 i~ provided between the connecting
our~acee 13 and 13a.
Fig. 3 shows an e~apo~a~or wall 2 in the wall arrangement
pursuant to Fig. 2 without the insulating la~er, as seen
~rom t~e outside. The u~broken d~l m~ tin~ lines o~ she
refrigerant duct 8, which has a substanclally ~n~
Ghaped course, project ae relie like ~he circular and o~al
~olid metal connections 11 in a ~idened re~e.ring zone. A~
i~ de~ignated by the dot-dash lineb, the re~rigerant duct
~r~nrhes numerously therein.
A pair o~ broken linei Pn~r~Qs~ the respec~i~ely
~ering separating layer 1~. It can be ~een that the
~eparating layer 14 is wider than the refr~gerant duc~ 8
~ig. 4 6ho~6 a perspective and sectlonal vie~ ~f a
separating wall 2 which con~ist~ o~ rhe inner-wall sheet 7,
the inner metal sheet 5, the ou~er metal 6~eet 6 and the
ou~er-wa~l ~heet 15.
In ~uch an ~vaporator wall 2 the inner-wall shee~ 7 and the
outer-~all sheet 15 cou}d be made of alumlnium ~Al 99.5)
and each ha~e a thick~ess of approx. 0.6 m~.

6 21 767~5
The lnner-~all sheet S i6 made f~om zirconium-containing
aluminium ~AlZr) and ha~ a thick~e~s of O.2 and O.6 ~m. The
outer-wall ~heet 6, with a ~hickne~ of O.5 ~m, i~ again
~ade ~rom AluminiU~ (Al 99.5)~ ~etween adjacent outer
connecting ~ur~aces 17 ~etween the outer-wall ~heet 15 and
the outer metal sheet 6 there are provided thin outer
separating layers 16 which also have a mea~der-~haped
course adapted to the meander~Fh~re~ ~our~e o~ the
refrigerant duct 8. The 3eparati~g layer~ howe~er are wider
than the refrigerant dUcr.
The connecting ~urfaces ~7 between the oute~-wall ~heet 15
and the outer metal sheet 6 are manufactured in ~ne pa~s
wit~ the with the roll-~elding of inner and outer metal
sheet 5, 6.

Representative Drawing