U.S. patent application number 12/315719 was filed with the patent office on 2009-04-30 for refrigerant compressor.
Invention is credited to Walter Brabek, Manfred Jost.
Application Number | 20090110586 12/315719 |
Document ID | / |
Family ID | 46578782 |
Filed Date | 2009-04-30 |
United States Patent
Application |
20090110586 |
Kind Code |
A1 |
Brabek; Walter ; et
al. |
April 30, 2009 |
Refrigerant compressor
Abstract
A hermetically encapsulated refrigerant compressor which
comprises a hermetically sealed compressor housing (1), in the
interior of which a piston-cylinder unit which compresses a
refrigerant and a suction pipe (2) and a pressure pipe (3) are
provided, with refrigerant flowing via the suction pipe (2) to the
piston-cylinder unit and the refrigerant compressed by the
piston-cylinder unit being conveyed out of the compressor housing
(1) via the pressure pipe (3), with connection openings (5) for the
suction pipe (2) and the pressure pipe (3) being provided on the
compressor housing (1), with the connection of the suction pipe (2)
and pressure pipe (3) to the connection openings (5) occurring in a
hermetically tight manner by means of a connection apparatus (9)
and with the connection apparatus (9) comprising a preferably
sleeve-like body element (8) and at least one spacer element (7)
which spaces the body element (8) from the suction pipe
(2)/pressure pipe (3). It is provided in accordance with the
invention that the body element (8) is attached to an outside (13)
of the compressor housing (1) outside of the connection opening (5)
by enclosing the same in a hermetically sealing manner.
Inventors: |
Brabek; Walter;
(Fuerstenfeld, AT) ; Jost; Manfred; (Feldbach,
AT) |
Correspondence
Address: |
COLLARD & ROE, P.C.
1077 NORTHERN BOULEVARD
ROSLYN
NY
11576
US
|
Family ID: |
46578782 |
Appl. No.: |
12/315719 |
Filed: |
December 5, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP07/55648 |
Jun 8, 2007 |
|
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12315719 |
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Current U.S.
Class: |
418/179 |
Current CPC
Class: |
F04C 29/04 20130101;
F04C 23/008 20130101; F04B 39/123 20130101; F04C 2230/60 20130101;
F04C 2240/30 20130101; F04C 2240/806 20130101 |
Class at
Publication: |
418/179 |
International
Class: |
F04C 29/00 20060101
F04C029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 8, 2007 |
AT |
GM 450/2006 |
Claims
1. A hermetically encapsulated refrigerant compressor which
comprises a hermetically sealed compressor housing (1), in the
interior of which a piston-cylinder unit which compresses a
refrigerant and a suction pipe (2) and a pressure pipe (3) are
provided, with refrigerant flowing via the suction pipe (2) to the
piston-cylinder unit and the refrigerant compressed by the
piston-cylinder unit being conveyed out of the compressor housing
(1) via the pressure pipe (3), with connection openings (5) for the
suction pipe (2) and the pressure pipe (3) being provided on the
compressor housing (1) which enable the overflow of the refrigerant
from the outside of the compressor housing (1) into the interior of
the compressor housing (1) and vice-versa, with the connection of
the suction pipe (2) or pressure pipe (3) to the connection
openings (5) occurring in a hermetically tight manner by means of a
connection apparatus (9), with the connection apparatus (9)
comprising a preferably sleeve-like body element (8) and at least
one spacer element (7) which spaces the body element (8) from the
suction pipe (2)/pressure pipe (3), wherein the body element (8) is
attached to an outside (13) of the compressor housing (1) outside
of the connection opening (5) by enclosing the same in a
hermetically sealing manner.
2. A hermetically encapsulated refrigerant compressor according to
claim 1, wherein the spacer element (7) consists of a material that
has a lower thermal conductivity than the body element (8).
3. A hermetically encapsulated refrigerant compressor according to
claim 1, wherein the body element (8) and preferably the spacer
element (7) is made of austenitic steel.
4. A hermetically encapsulated refrigerant compressor according to
claim 1, wherein the spacer element (7) is made of foamed glass,
plastic or a ceramic material.
5. A hermetically encapsulated refrigerant compressor according to
claim 1, wherein the spacer element (7) is arranged between body
element (8) and the suction pipe (2)/pressure pipe (3) and encloses
the suction pipe (2)/pressure pipe (3) in a hermetically sealing
manner.
6. A hermetically encapsulated refrigerant compressor according to
claim 1, wherein the spacer element (7) is a section, preferably an
end section of the body element (8), which extends under an angular
inclination, preferably a right angle, relative to the axis of the
suction pipe (2)/pressure pipe (3) and encloses the suction pipe
(2)/pressure pipe (3) in a hermetically sealing manner.
7. A hermetically encapsulated refrigerant compressor according to
claim 6, wherein the section or end section of the body element (8)
encloses the suction pipe (2)/pressure pipe (3) at a section of the
circumference which lies outside of the connection opening (5) or
outside of cross-sectional wall surface of the compressor housing
(1) which is projected in the normal direction onto the
circumferential surface of the body element (8).
8. A hermetically encapsulated refrigerant compressor according to
claim 6, wherein the section or end section of the body element (8)
which is arranged as a spacer element (7) ends in an annular
opening.
9. A hermetically encapsulated refrigerant compressor according to
claim 1, wherein the body element (8) has a contact section (10)
and is fastened with the same to the outside (13) of the compressor
housing (1), with the diameter of the connection opening (5)
preferably being larger than the outer diameter of the section of
the body element (8) which is guided through the connection opening
(5), so that an abutting surface area (11) of the connection
opening (5) is spaced from the body element (8).
10. A hermetically encapsulated refrigerant compressor according to
claim 1, wherein the body element (8) and/or the spacer element (7)
are arranged in several parts.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a hermetically encapsulated
refrigerant compressor which comprises a hermetically sealed
compressor housing, in the interior of which a piston-cylinder unit
which compresses a refrigerant and a suction pipe and a pressure
pipe are provided, with refrigerant flowing via the suction pipe to
the piston-cylinder unit and the refrigerant compressed by the
piston-cylinder unit being conveyed out of the compressor housing
via the pressure pipe, with connection openings for the suction
pipe and the pressure pipe being provided on the compressor housing
which enable the overflow of the refrigerant from the outside of
the compressor housing into the interior of the compressor housing
and vice-versa, with the connection of the suction pipe and
pressure pipe to the connection opening occurring in a hermetically
tight manner by means of a connection apparatus, with the
connection apparatus comprising a preferably sleeve-like body
element and at least one spacer element which spaces the body
element from the suction pipe/pressure pipe, in accordance with the
preamble of claim 1.
[0002] Such refrigerant compressors are used in the field of
households and the industry where they are mostly arranged on the
rear side of a refrigerator or refrigerated case. It is their task
to compress and further convey refrigerant circulating in the
cooling system, thus dissipating heat from the interior of the
refrigerating, passing it on to the ambient environment and a
refrigerating chamber or refrigerated case are thus refrigerated in
the known manner.
[0003] The refrigerant compressor comprises a hermetically sealed
compressor housing and an electric motor which drives a piston
oscillating in a cylinder via a crankshaft to compress the
refrigerant. The compressor housing consists of a cover part and a
base part and connection openings, with a suction pipe, a pressure
pipe and other pipes optionally being provided which lead into and
out of the compressor housing to convey the refrigerant to the
cylinder and therefrom further in the refrigerant loop.
[0004] In view of the large number of refrigerant compressors all
over the world, any degree of improvement in the efficiency made in
a refrigerant compressor leads to a considerable potential in
energy savings which is becoming increasingly more important in
view of the globally diminishing energy resources.
[0005] Possibilities for an improvement of the efficiency are
especially the reduction of the temperature of the refrigerant at
the beginning of the compression process. Any reduction of the
intake temperature into the cylinder of the cylinder-piston unit
therefore causes, like the reduction of the temperature during the
compression process and, connected thereto, the expulsion
temperature, a reduction of the required technical work for the
compression process.
DESCRIPTION OF THE PRIOR ART
[0006] In known hermetically encapsulated refrigerant compressors
there is a strong heating of the refrigerant on its path from the
compressor (cooling space) to the intake valve of the
piston-cylinder unit as a result of the design. Since a
considerable quantity of heat is generated as a result of the
compression process and the same is also transferred to the
compressor housing, there is obviously also a subsequent heat
transfer from the compressor housing to the pipe connections of the
refrigerant compressor, especially to the suction pipe.
[0007] The pressure pipe indirectly also causes an additional
heating of the suction pipe and thus the refrigerant which is
directly before the compression cycle. Since the compressed
refrigerant which is removed in the pressure pipe has temperatures
of up to 100.degree. C., there is also a strong heating of the
pressure pipe which is transferred especially also in the area of
the connection opening onto the compressor housing and from this to
the suction pipe.
[0008] Since the drawn refrigerant is thus heated, there is an
adverse effect on the efficiency of the refrigerant compressor.
[0009] In addition to a known insulation of the sections of the
suction and pressure pipes which are guided in the interior space
of the compressor housing, an insulation of the same in the area of
the connection openings is of special relevance, i.e. at such a
location where the suction pipe and pressure pipe and the
compressor housing touch each other directly.
[0010] A compressor housing with a suction pipe consisting of two
pipe elements that are slid into each other is known from U.S. Pat.
No. 6,361,293, with the pipe element with the smaller diameter
comprising an enlarged end section which is provided with an O-ring
and makes contact with the inside of the other pipe element. This
measure is provided to ensure mobility of the suction pipe
connected to a cylinder housing. As a result of the thus obtained
air gap between the outside diameter of the first pipe element and
the inside diameter of the second pipe element, a certain
insulating effect against the conveyed refrigerant is also obtained
in the connection region of the compressor housing, but the
reduction of the heat transmission thus achieved is relatively low
because the wall of the compressor housing ends directly on the
suction pipe.
[0011] U.S. 2004/096338 A1 discloses a compressor housing with a
tubular body element which is guided through the wall of the
compressor housing in order to receive a pressure pipe, with an
insert or spacer element that is also tubular being arranged
between the body element and the pressure pipe. The spacer element
is welded together at the end side with the pressure pipe, while
the body element is welded together at the end side with the spacer
element.
[0012] A hermetically sealed compressor housing with a pipe
connection apparatus is known from U.S. Pat. No. 6,257,846 B1, with
an outer sleeve element which is guided through the wall of the
compressor housing and an inner sleeve element being provided. A
suction pipe is held within the inner sleeve element. The inner and
outer sleeve element and the suction pipe are soldered together
simultaneously.
[0013] A compressor housing is known from EP 0 430 790 A1 whose
components in adjacent areas are provided with a hermetically
sealing layer or a bulge in order to dampen vibrations. It also
discloses a pressure pipe connection with a body element made of an
elastic material. Said body element is fastened by means of an
adhesive layer to the housing wall and the pressure pipe.
SUMMARY OF THE INVENTION
[0014] It is therefore the object of the present invention to
reduce the efficiency losses caused by the heating of the aspirated
refrigerant in the area of the connection openings of the
compressor housing and to optimize the efficiency of the
refrigerant compressors. A connection apparatus is to be provided
for this purpose which considerably reduces the heat transmission
between the compressor housing and suction pipe or pressure pipe,
so that the lowest possible temperature level of the refrigerant is
ensured at the beginning of the compression process, i.e. during
the aspiration into the cylinder of the piston-cylinder unit.
[0015] This is achieved in accordance with the invention by a
refrigerant compressor with the characterizing features of claim
1.
[0016] A refrigerant compressor comprises a hermetically sealed
compressor housing in the interior of which a piston-cylinder unit
works which compresses a refrigerant and a suction pipe and a
pressure pipe is provided, with a refrigerant flowing in the known
manner via the suction pipe to the piston-cylinder unit and the
refrigerant compressed by the piston-cylinder unit being expelled
from the compressor housing via the pressure pipe, with connection
openings being provided on the compressor housing for the suction
pipe and the pressure pipe which enable the overflow of the
refrigerant from the outside of the compressor housing to the
inside of the compressor housing and vice-versa, with the
connection of the suction pipe or the pressure pipe to the
connection opening. occurring in a hermetically sealed way through
a connection apparatus. The connection apparatus comprises a
preferably sleeve-like body element and at least one spacer element
which keeps the body element away from the suction pipe and
pressure pipe. The body element is thus not in direct contact with
the suction pipe and pressure and the introduction of heat into the
body element occurs only to a limited extent through the spacer
element.
[0017] In accordance with the invention, the body element is
attached outside of the connection opening to an outside of the
compressor housing by enclosing the same in a hermetically sealing
manner.
[0018] The body element can either be fastened with one face side
directly to the compressor housing or by means of a contact section
which is bent off at an angle of 90.degree. for example.
[0019] Since the heat transmission from the compressor housing to
the suction pipe or from the hot pressure pipe to the compressor
housing and subsequently from the same to the suction pipe is
reduced, a considerable reduction of the temperature of the
refrigerant which is guided in the suction pipe and is directly
before the compression process in the piston-cylinder unit is
achieved, thus leading to an increase in the efficiency of the
refrigerant compressor. By avoiding the heat transmission from the
hot pressure pipe to the compressor housing, a heating of the
compressor housing itself and the interior of the compressor
housing (oil, the refrigerant disposed in the interior, compressor
housing temperature) is reduced, leading to an improvement in the
efficiency.
[0020] According to the characterizing features of claim 2 it is
provided that the spacer element consists of a material that has a
lower thermal conductivity than the body element in order to avoid
heat transmission to a highest possible extent.
[0021] According to the characterizing features of claim 3, the
body element and preferably also the spacer element is made of
austenitic steel. Austenitic steel is characterized in the present
field of application by its reduced thermal conductivity and a high
resistance to corrosion, tenacity and resistance to high
temperatures.
[0022] According to another preferred embodiment of the invention,
the spacer element is made of foamed glass, plastic or a ceramic
material according to the characterizing features of claim 4. The
mentioned materials lead to a strong reduction of the undesirable
heat transmission from the compressor housing or the body element
in direct contact with the same to the suction pipe and vice-versa
from the pressure pipe to the body element and the compressor
housing as a result of their low heat transmission coefficient.
[0023] In addition to a direct arrangement of a separate spacer
element having an insulating effect between the body element and
the suction pipe or pressure pipe according to the characterizing
features of claim 5, with the suction pipe or pressure pipe being
enclosed by the spacer element in a hermetically sealing manner, it
is also possible in an alternative embodiment to arrange the body
element and the spacer element as an integral component. As such it
is provided for according to the characterizing features of claim 6
that the spacer element is arranged as a section, preferably an end
section of the body element, which extends under an angular
inclination, preferably a right angle, relative to the axis of the
suction pipe or pressure pipe in order to enclose the suction pipe
or pressure pipe in a hermetically sealing manner. Since this
geometry also leads to the consequence that the inside diameter of
the body element (with the mere exception of its end section) is
always larger than the outside diameter of the suction
pipe/pressure pipe, an air cushion is formed between the suction
pipe/pressure pipe which has an insulating function and strongly
reduces the undesirable heat transmission between the suction
pipe/pressure pipe and the compressor housing. This embodiment
allows a simple and economical production of the connection
apparatus.
[0024] In this embodiment it is provided according to the
characterizing features of claim 7 that the section or end section
of the body element encloses the suction pipe/pressure pipe at a
section of its longitudinal extension which lies outside of the
connection opening or outside of the cross-sectional wall surface
of the compressor housing which is projected in the normal
direction onto the circumferential surface of the body element.
Since the contact surface of the section or the end section of the
body element with the suction pipe/pressure pipe is as far away as
possible from the contact surface of the body element with the
compressor housing, the path of heat transport to be bridged is
extended and the heat transmission between suction pipe/pressure
pipe and compressor housing is given the largest possible
obstruction.
[0025] In order to enclose the suction pipe/pressure pipe in a
hermetically sealing manner, the end section of the body element
which is arranged as a spacer element is provided with an annular
opening according to the characterizing features of claim 8.
[0026] According to the characterizing features of claim 9, the
body element comprises a contact section which is fastened to the
one on the outside of the compressor housing. The diameter of the
connection opening is preferably larger than the outer diameter of
the section of the body element which is led through the connection
opening. It is thus ensured that an abutting surface of the
connection opening does not touch the body element, but remains
spaced from the same. This measure too ensures that the insulating
function of the connection apparatus in accordance with the
invention is increased and the heat transmission between the
suction pipe/pressure pipe and compressor housing is reduced.
[0027] Both the body element as well as the spacer element can also
be arranged in several parts according to the characterizing
features of claim 10 in order to enable further advantages in
relation to production and heat technology.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The invention is now explained in closer detail by reference
to an embodiment, wherein:
[0029] FIG. 1 shows a basic part of a compressor housing in an
oblique view;
[0030] FIG. 2 shows a basic part of a compressor housing in a top
view;
[0031] FIG. 3 shows a partial sectional view of the compressor
housing of FIG. 2 along lines A-A and B-B with a connection
apparatus according to the state of the art;
[0032] FIG. 4 shows an enlarged view of the detail A of FIG. 3;
[0033] FIG. 5 shows an alternative embodiment of a connection
apparatus according to the state of the art;
[0034] FIG. 6 shows a further alternative embodiment of a
connection apparatus according to the state of the art;
[0035] FIG. 7 shows a further alternative embodiment of a
connection apparatus according to the state of the art;
[0036] FIG. 8 shows a further alternative embodiment of a
connection apparatus according to the state of the art;
[0037] FIG. 9 shows an embodiment of a connection apparatus
according to the invention;
[0038] FIG. 10 shows a further embodiment of a connection apparatus
according to the invention;
[0039] FIG. 11 shows a further embodiment of a connection apparatus
according to the invention;
[0040] FIG. 12 shows a further embodiment of a connection apparatus
according to the invention;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] A refrigerant compressor comprises a hermetically sealed
compressor housing 1, with a suction pipe 2, a pressure pipe 3 and
a service pipe 4 opening into the same via connection openings
5.
[0042] A refrigerant flows via the suction tube 2 in the known
manner to a piston-cylinder unit (not shown) which is arranged
within the compressor housing 1 and in which a compression of the
refrigerant occurs, with the pressure pipe 3 subsequently leading
the compressed and therefore strongly heated refrigerant from the
piston-cylinder unit out of the compressor housing 1 to a cooling
circuit (also not shown) of a cooling space. The piston-cylinder
unit is driven by an electromotor via a crankshaft, so that cooling
space associated with the refrigerant compressor is continually
cooled by means of the circulating refrigerant.
[0043] Compressor housing 1 comprises several standing elements 6
which are used to position the same on a floor space of a
refrigerating device determined for this purpose.
[0044] Although FIG. 1 merely shows a base part of a compressor
housing 1 in this connection on which subsequently a cover part
(not shown) will be placed, the compressor housing 1 can also be
arranged in another manner, e.g. in the form of a compressor
housing 1 which is divided in an oblique way or composed in another
manner. It is also possible to lead the suction pipe 2, the
pressure pipe 3 or service pipe 4 through the cover part into the
interior of the compressor housing, with suction pipe 2 and
pressure pipe 3 not needing to extend necessarily in pairs next to
one another as shown in FIG. 1, but can also open in connection
openings 5 of the compressor housing 1 which are arranged offset in
a random way, or can lead out of the same.
[0045] Service pipe 4 is merely used for filling the compressor
housing 1 with a suitable refrigerant or with an oil required for
lubrication.
[0046] FIG. 2 shows a top view of the compressor housing 1 shown in
FIG. 1 in an oblique view and forms the reference for the partial
sectional view as shown in FIG. 1 with the sectional guides A-A and
B-B as shown therein, which partial sectional view shows a
conventional pipe connection to the compressor housing 1 as known
from the state of the art. The suction pipe and/or the pressure
pipe pass through the connection opening 5 through a connection
apparatus 9 which is connected with the compressor housing 1 in a
hermetically sealed manner, with the connection apparatus 9 on its
part being connected with the suction pipe and pressure pipe in a
hermetically sealed manner, preferably by being welded.
[0047] FIGS. 4 and 5 also show pipe connections according to the
state of the art in a detailed view. The compressor housing 1
mostly consists of deep-drawing steel, whereas the suction pipe 2
and the pressure pipe 3 consist of copper, a copper/iron alloy or
also of a pure iron material. According to the illustration in FIG.
4 it is common practice to fasten the suction pipe 2 and the
pressure pipe 3 by means of a connection apparatus 9 to the
connection openings 5 of the compressor housing 1. For this
purpose, a steel disk is soldered onto suction pipe 2 and pressure
pipe 3 for example and this system is welded in a further process
of work to the compressor housing 1. The connection opening 5 or
the area of the compressor housing 1 enclosing the same can be
prepared in a manner that an interlocking contact is enabled
between the mutually contacting surfaces of the compressor housing
1 and the connection apparatus 9, e.g. by mutually corresponding
bezels 14 (FIG. 4) which are provided both on the connection
apparatus 9 as well as the compressor housing 1.
[0048] Another kind of connection of the suction pipe 2 and
pressure pipe 3 to the compressor housing 1 is shown in FIG. 5,
with a Cu or Cu/Fe pipe being shown which was swaged and is brought
into contact with a bezel 14 of the connection opening 5 of the
compressor housing 1 by means of a protrusion of the pipe cross
section which was obtained in the course of the swaging and is
connected in a hermetically sealed manner with the compressor
housing 1 by means of welding for example.
[0049] FIGS. 6 to 8 show other connection possibilities for the
suction pipe 2/pressure pipe 3 as known from the state of the art,
comprising a contact of the connection apparatus 9 with the outside
13 of the compressor housing 1 (FIG. 7), a pipe connection with
contact of the connection apparatus 9 with inside 12 of the
compressor housing 1 (FIG. 8) or a pipe connection without contact
of the connection apparatus 9 on the compressor housing (FIG.
9)
[0050] Irrespective of how the pipe connection may have been
arranged according to the previously described FIGS. 3 to 8
specifically, it is a fact in the known connection variants that a
connection apparatus 9 made of a metallic material or a metal alloy
provides a high heat transmission from the compressor housing 1 to
the suction pipe 2 and from the pressure pipe 3 which carries a
strongly heated refrigerant to the compressor housing 1 and thus
again to the suction pipe 2 which is in direct contact with the
compressor housing 1 or is in direct contact via the connection
apparatus 9. An unhindered heat transmission at the mentioned
places is undesirable for the reasons as explained above and
reduces the efficiency of the refrigerant compressor because the
refrigerant drawn into the cylinder of the piston-cylinder unit is
heated unnecessarily in this process.
[0051] In order to considerably reduce such a heat transmission
from the compressor housing 1 to the suction pipe 2 and from the
pressure pipe 3 to the compressor housing 1, the connection
apparatus 9 comprises a body element 8 and at least one spacer
element 7 which spaces the body element 8 from the suction pipe 2
and pressure pipe 3. Body element 8 therefore is no longer in
direct contact with the suction pipe 2 or pressure pipe 3, or the
contact zones between these elements are kept very small.
[0052] In accordance with the invention, the body element 8 is
arranged on the compressor housing 1 outside of the connection
opening 5 and enclosing the same (FIG. 11) . The body element 8 is
fastened with an obtuse cross-sectional surface area directly to
the outside 13 of the compressor housing 1. A contact section which
is bent by an angle of 90.degree. for example can also be provided
for a more stable fastening of the body element 8.
[0053] If the body element 8 is not arranged on the outside 13 but
on the inside 12 (as shown in FIG. 11), a rear venting space is
formed between the suction pipe 2/pressure pipe 3 and body element
8, which space communicates with the ambient air indicated by
arrows 15 outside of the compressor housing 1 via the connection
opening 5 of the compressor housing 1 and thus enables an
additional cooling effect. The diameter of the connection opening 5
is larger for this purpose than the diameter of the suction pipe
2/pressure pipe 3.
[0054] FIG. 11 already shows an alternative embodiment of the
connection apparatus 9, with body element 8 and spacer element 7
being arranged as an integral component. The spacer element 7 is
arranged as an end section of the body element 8 which extends
under an angular inclination, preferably at a right angle, to the
axis of the suction pipe 2/pressure pipe 3 in order to enclose the
suction pipe 2/pressure pipe 3 in a hermetically sealing manner,
e.g. by soldering or welding.
[0055] The body element 8 is preferably arranged in a sleeve-like
manner, and thus comprises a wall section (see FIG. 9) which
extends substantially parallel to the axis of the suction pipe
2/pressure pipe 3 or to the axis of the connection opening 5.
optionally, it is also possible to provide any other shape of the
arrangement instead of a rotational-symmetrical shape of the body
element 8. Instead of a sleeve-like or cylindrical shape, the body
element 8 can also be arranged in a convex, concave or irregular
geometrical way. The relevant aspect is always that the body
element 8 does not touch the suction pipe 2/pressure pipe 3 over a
length which enables an unhindered heat transmission, but is spaced
from the same via a spacer element 7, even if only minimally. In a
preferred embodiment according to FIG. 9, a cylindrical foamed
glass body is used as a spacer element 7 which is arranged between
body element 8 and the suction pipe 2/pressure pipe 3, with the
foamed glass body being connected in a hermetically sealed manner
with the suction pipe 2/pressure pipe 3 on the one hand and the
body element 8 on the other hand.
[0056] In order to reduce heat transmission to the highest possible
extent, the spacer element 7 preferably consists of a material that
has a worse thermal conductivity than the body element 8. In order
to fasten the body element 8 reliably on the compressor housing 1,
it can be provided with a stop section 10 which rests on the
outside 13 or on the inside 12 of the compressor housing 1 and is
fastened there in the known manner, i.e. it is soldered or welded.
The contact section 10 preferably concerns an integral part of the
body element 8 which is provided with its desired dimensioning in a
bending or deep drawing process. In the case of a multi-part
arrangement of the body element 8, the contact section 10 can also
be made as a separate element which is soldered or welded onto the
sleeve-like body element 8.
[0057] In order to further reduce the heat transmission between
compressor housing 1 and the suction pipe 2/pressure pipe 3, the
diameter of the connection opening 5 is dimensioned larger than the
outer diameter of the section of the body element 8 which is guided
through the connection opening 5. It is thus ensured that an
abutting surface 11 of the connection opening 5 does not contact
the body element 8, but is spaced from the same. An annular gap is
thus formed in this way between the body element 8 and the abutting
surface 11 in which outside air can circulate and can cool the
connection apparatus 9.
[0058] When choosing suitable materials for the spacer element 7,
its coefficient of thermal conduction .lamda. is of relevance; it
defines the heat quantity which passes in a unit of time through a
layer of the surface area and thickness unit at 1 K temperature
difference and is expressed in W/(m*K). Whereas copper
(temperature-dependent) has a comparatively high coefficient of
thermal conduction .lamda. of approximately 380 W/(m*K), .lamda. in
unalloyed steel is approximately 100 W/(m*K) . By adding suitable
alloy elements such as chromium, nickel, manganese or molybdenum,
the coefficient of thermal conduction .lamda. of steel can be
reduced to a considerable extent. Cr/Ni steel can have a
coefficient of thermal conduction .lamda. of less than 20 W/(m*K)
for example.
[0059] The already mentioned material of foamed glass with a
coefficient of thermal conduction .lamda. of approximately only
0.05 W/(m*K) has proven in tests to be especially advantageous.
Foamed glass has an only slightly larger .lamda.-value than air
with 0.024 W/(m*K).
[0060] Similarly, ceramic materials have proven to be very
advantageous in the present field of application, especially such
on the basis of metal oxides. For example, so-called special
ceramic masses or technical masses such as highly sintered oxide
ceramics made of aluminum, magnesium, beryllium or zirconium oxide
can be used.
[0061] Preferably, solderable ceramic materials are concerned, so
that perfect soldering of spacer element 7 and suction pipe
2/pressure pipe 3 on the one hand and body element 8 and even
compressor housing 1 on the other hand is enabled in order to
achieve the required tightness.
[0062] Ceramic materials have proven to be especially advantageous
for use in insulating suction pipe 2/pressure pipe 3 at their
connection point on the compressor housing 1 as a result of their
fire resistance and their temperature and dimensional stability in
addition to their low coefficient of thermal conduction
[.lamda.=0.5-1.5 W/(m*K)].
[0063] Plastic materials which offer temperature stability and
resistance to ageing can also be used as materials for the spacer
element 7, which materials are applied by suitable fastening
measures such as shrinking, gluing, lasing, extrusion-coating or
laminating onto the suction pipe 2/pressure pipe 3.
[0064] As a result of their low coefficient of thermal conduction,
the mentioned materials lead to a strong reduction in the
undesirable heat transmission from the compressor housing 1 or from
the body element 8 which is in direct contact with the same onto
the suction pipe 2 and vice-versa from the pressure pipe 3 to the
body element 8 and the compressor housing 1.
[0065] Austenitic steel is preferred as a material for the body
element 8. Austenitic steel is characterized in the present field
of application by its alloy percentage (e.g. Cr/Ni or Mg-alloys)
with a reduced thermal conductivity and a high resistance to
corrosion, tenacity and high-temperature resistance. At the same
time, this material also allows hermetically sealed connection of
the body part 8 to the compressor housing by means of welding.
[0066] FIG. 10 shows an alternative embodiment of the connection
apparatus 9, with the body element 8 and the spacer element 7 being
arranged as an integral component. The spacer element 7 is arranged
as an end section of the body element 8 which extends under an
angular inclination, preferably a right angle to the axis of the
suction pipe 2/pressure pipe 3 in order to enclose the suction pipe
2/pressure pipe 3 in a hermetically sealing manner, e.g. by
soldering or welding.
[0067] As is shown in the illustration according to FIG. 10, the
inside diameter of the sleeve-like body element 8 is always larger
than the outside diameter of the suction pipe 2/pressure pipe 3, so
that an air cushion (gas mixture, refrigerant) is formed between
the suction pipe 2/pressure pipe 3 and the body element 8 which has
an insulating function and also strongly reduces the heat
transmission between suction pipe 2/pressure pipe 3 and compressor
housing 1. Similarly, the end section of the body element 8 can
also be a separately produced element which is attached to the face
side of the sleeve-like body element 8 and encloses the suction
pipe 2/pressure pipe 3. The relevant aspect is that the heat flow
from the body element 8 to the suction pipe 2 and from the pressure
pipe 3 to the body element 8 occurs only via the spacer element 7
due to lack of contact between body element and suction pipe
2/pressure pipe 3, with the body element 8 and the spacer element 7
being produced in an integral way or also in several parts.
[0068] Body element 8 can also be arranged in a position reversed
over the one shown in FIG. 10, i.e. with an end section as a spacer
element 7 which is arranged in the area of the inside 12 of the
compressor housing 1, with the suction pipe/pressure pipe section
being subjected in the area of the connection opening to a rear
ventilation and cooling by the air enclosing the compressor housing
1.
[0069] As is further shown in FIG. 10, the end section of the body
element 8 encloses the suction pipe 2/pressure pipe 3 at a section
of its longitudinal extension which lies outside of the connection
opening 5 or outside of a cross-sectional wall surface of the
compressor housing 1 projected against the circumferential surface
of the body element 8. The contact surface of the end section of
the body element 8 with the suction pipe 2/pressure pipe 3 is
therefore not arranged in the direct vicinity of the contact
surface of the body element 8 with the compressor housing 1, but at
a distance promoting the insulating function.
[0070] In order to enclose the suction pipe 2/pressure pipe 3 and
to enable a hermetically sealing connection with the same, the end
section of the body element 8 which is arranged as a spacer element
7 is provided with an annular opening within which the suction pipe
2/pressure pipe 3 is fastened in a sealed manner.
[0071] In order to achieve further production and thermal
advantages in the respective application, it may optionally be
appropriate to arrange the body element and/or the spacer element 7
in several parts. A body element 8 in several parts which consists
of several elements engaging into each other has the advantage of
larger flexibility in the production and surface machining and
allows for a specific arrangement of the connection system
depending on the respective requirements and fields of
application.
[0072] FIG. 12 finally shows a special embodiment of a connection
apparatus 9 which comprises a spacer element 7 which is preferably
made of foamed glass, plastic or ceramic material, with the spacer
element 7 being arranged in an L-shaped way and being arranged
directly between the abutting area 11 of the connection opening 5
and suction pipe 2/pressure pipe 3. A leg section 16 of the spacer
element 7 is enclosed by the body element 8 and pressed against the
outside 13 of the compressor housing 1. The spacer element 7 need
not necessarily have a hermetically sealing function in this
configuration if the body element 8 is connected in a hermetically
sealing manner both with the compressor housing 1 as well as the
suction pipe 2/pressure pipe 3. This configuration thus offers the
advantage that materials can also be used for the spacer element 7
with which a hermetically sealing connection can be produced only
with difficulty to another medium, especially such materials which
cannot be soldered or welded.
* * * * *