U.S. patent application number 10/539301 was filed with the patent office on 2006-06-08 for reciprocating compressor for compressing refrigerant.
Invention is credited to Won-Hyun Jung, Dong-Won Lee, Su-Won Lee.
Application Number | 20060120891 10/539301 |
Document ID | / |
Family ID | 36165427 |
Filed Date | 2006-06-08 |
United States Patent
Application |
20060120891 |
Kind Code |
A1 |
Jung; Won-Hyun ; et
al. |
June 8, 2006 |
Reciprocating compressor for compressing refrigerant
Abstract
A reciprocating compressor includes a driving unit (10) disposed
inside a hermetic container (86) and generating a reciprocal
motional force, a compression unit (10) for performing a
compressing operation on a refrigerant upon receiving the
reciprocal motional force generated from the driving unit (8); and
a lubrication unit (12) for supplying a lubricant to each motional
portion of the driving unit (8) and the compression unit (10) to
perform a lubrication operation. Hydrocarbon consisting of carbon
and hydrogen, a sort of natural refrigerant, is used as the
refrigerant. The lubricant is a paraffin-based mineral lubricant,
which is a sort of mineral oil and well harmonized with the natural
refrigerant used for a refrigerator. Accordingly, a lubricating
performance is improved and thus a performance of the reciprocating
compressor can be enhanced.
Inventors: |
Jung; Won-Hyun;
(Gyungsangnam-Do, KR) ; Lee; Su-Won;
(Gyungsangnam-Do, KR) ; Lee; Dong-Won;
(Gyungsangnam-Do, KR) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
36165427 |
Appl. No.: |
10/539301 |
Filed: |
July 10, 2003 |
PCT Filed: |
July 10, 2003 |
PCT NO: |
PCT/KR03/01374 |
371 Date: |
June 16, 2005 |
Current U.S.
Class: |
417/366 ;
417/416; 417/417 |
Current CPC
Class: |
F04B 39/0276 20130101;
F04B 35/045 20130101; F04B 39/0215 20130101; F04B 39/0292
20130101 |
Class at
Publication: |
417/366 ;
417/417; 417/416 |
International
Class: |
F04B 39/06 20060101
F04B039/06; F04B 35/04 20060101 F04B035/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2002 |
KR |
10-2002-0081897 |
Claims
1. A reciprocating compressor for compressing a refrigerant
comprising: a hermetic container to which a suction pipe and a
discharge pipe are connected; a driving unit having a stator fixed
inside the hermetic container and a mover disposed spaced apart
from the stator and linearly and reciprocally moved according to an
interaction with the stator; an organic compound refrigerant sucked
into the suction pipe, having an combustibility and explosiveness
and consisting of only carbon and hydrogen; a compression unit for
receiving a reciprocal motional force of the driving unit and
making a compression operation on the organic compound refrigerant;
and a mineral-based lubricant filled at a lower portion of the
hermetic container; and a lubrication unit for supplying the
mineral-based lubricant to each motional portion of the driving
unit and the compression unit and performing a lubricating
operation
2. The reciprocating compressor of claim 1, wherein the stator
comprises: an outer stator fixed at the hermetic container; an
inner stator disposed with a certain air gap with an inner
circumferential surface of the outer stator; and a winding coil
wound at one of the outer stator and the inner stator, to which
power is applied from an external source, and the mover comprises:
magnets disposed at regular intervals between the outer stator and
the inner stator and being linearly and reciprocally moved when
power is applied to the winding coil; and a magnet frame having the
magnets mounted thereon and transmitting a linear and reciprocal
motional force to the compression unit.
3. The reciprocating compressor of claim 1, wherein the compression
unit comprises: a piston connected to the mover and linearly and
reciprocally moved; a cylinder, into which the piston is slidably
inserted, for forming a certain compression chamber; a suction
valve mounted at a refrigerant passage formed at the piston and
preventing a backflow of the refrigerant after being introduced
into the compression chamber; and a discharge valve mounted at the
front side of the cylinder and performing an opening and closing
operation on the compressed refrigerant.
4. The reciprocating compressor of claim 1, wherein the lubrication
unit comprises: a lubricant pumping unit for pumping the lubricant
filled as much as a certain amount at a lower portion of the
hermetic container; and a lubricant supply passage for supplying
the lubricant pumped by the lubricant pumping unit to a frictional
portion between the piston and the cylinder.
5. The reciprocating compressor of claim 1, wherein the refrigerant
is isobutane (R600a) which is hydrocarbon-based and has a molecular
formula of CH(CH.sub.3).sub.3.
6. The reciprocating compressor of claim 1, wherein the lubricant
is a paraffin-based lubricant.
7. The reciprocating compressor of claim 1, wherein the lubricant
has a density of 0.866.about.0.880 g/cm.sup.3 at a temperature of
15.degree. C. and a flash point of above 140.degree. C.
8. The reciprocating compressor of claim 1, wherein the lubricant
has a kinematic viscosity of 7.2.about.21.8 mm.sup.2/s at a
temperature of 40.degree. C. and a viscosity index of
73.about.99.
9. The reciprocating compressor of claim 1, wherein the lubricant
has a flow point of below -25.degree. C. and a total acid number of
below 0.01 mgKOH/g.
10. The reciprocating compressor of claim 1, wherein the lubricant
has a water content of below 20 ppm and a breakdown voltage of
above 30 kV.
Description
TECHNICAL FIELD
[0001] The present invention relates to a reciprocating compressor
for compressing a refrigerant in a refrigerator, and more
particularly, to a reciprocating compressor for compressing a
refrigerant that is capable of improving a lubricating performance
by using a lubricant with an excellent compatibility with a
refrigerant used for a refrigerator and improving a performance of
the refrigerator.
BACKGROUND ART
[0002] As chlorofluorocarbon (CFC), a refrigerant used for a
refrigerator, an air-conditioner or the like, has been known as a
source material damaging an ozone layer of the stratosphere,
researches on a substitute refrigerant is being actively
conducted.
[0003] The CFC comprises R11 (trichloromonogluoromethane), R12
(dichlorodifluoromethane), R13 and the like, of which R12 mainly
used as a refrigerant for a refrigerator is one of
regulation-subject materials as being a source material causing an
ozone layer reduction and generating a global warming effect. Thus,
researches on a natural refrigerant is being actively conducted as
a substitute refrigerant.
[0004] The natural refrigerant refers to a material used as a
refrigerant which naturally exists in the globe such as water,
ammonia, nitride, carbon dioxide, propane, butane and the like, not
an artificial compound. Known that it does not have a bad influence
on the global environment, application of the natural refrigerant
as a refrigerant is positively reviewed.
[0005] Among the natural refrigerants, hydrocarbon comprises only
carbon and hydrogen and includes R50 (methane), R170 (ethane), R290
(propane), R600 (butane), R600a (isobutene), R1270 (propylene) or
the like. Hydrocarbon is not toxic and chemically stable and
especially exhibits an appropriate solubility in a mineral oil.
[0006] In addition, the hydrocarbon has a zero ozone depletion
potential and a very low global warming index. That is, when a
global warming index of carbon dioxide is admitted as `1`, a global
warming index of R12 is 7100, R134a is 1200, while propane is very
low, 3.
[0007] Especially, isobutane (R600a) is an environmental-friendly
natural gas which does not damage the ozone layer and have no
influence on a greenhouse effect. That is, isobutane (R600a), a
sort of a natural gas obtained by refining hydrocarbon gas created
in an oil refining process to a high degree of purity, is a
refrigerant containing no environmentally detrimental factor.
[0008] However, with all those advantages, isobutene (R600a) is
hardly combined with refrigerant oil currently used for a
refrigerating system due to its chemical and electrical properties.
Therefore, a refrigerant oil suitable for isobutene (R600a) is in
need of development. Especially, necessity of a refrigerant oil
usable for a reciprocating compressor for compressing isobutene
(R600a) comes to the front.
[0009] As shown in FIG. 1, the currently used reciprocating
compressor includes: a hermetic container 6 having a suction pipe 2
for sucking a refrigerant and a discharge pipe 4 for discharging a
compressed refrigerant each as being connected thereto; a driving
unit 8 disposed inside the case 6 and generating a reciprocal
motional force; a compression unit 10 for receiving the reciprocal
motional force from the driving unit 8 and compressing the
refrigerant; and a lubrication unit 12 for lubricating each
motional portion of the driving unit 8 and the compression unit
10.
[0010] In the reciprocating compressor, when the driving unit 8 is
driven and the compression unit 10 makes a compression operation on
the refrigerant, the lubrication unit 12 supplies a lubricant 50
stored at the lower portion of the hermetic container 6 to the
motional portion of the compression unit, thereby performing a
lubricating operation. The refrigerant compressed in the
compression unit is the natural refrigerant.
[0011] Since the lubricant used for the reciprocating compressor
constructed and operated as described above is used as a
refrigerant oil for the compressor compressing the natural
refrigerant, its physical and chemical properties should be in good
harmony with the natural refrigerant.
[0012] Namely, the lubricant used as the refrigerant oil of the
reciprocating compressor needs to have characteristics that it can
protect well an oil film even though the refrigerant is dissolved,
should be thermally and chemically stable so as not to react in
spite of being in contact with the refrigerant and an organic
material metal at a high temperature or at a low temperature, and
should have a high level thermal stability so as not to generate a
carbon sludge not to be oxidized at a high temperature part of the
compressor.
[0013] In order to satisfy those characteristics, characters of the
lubricant, such as a kinematic viscosity, a pour point, a density,
a total acid number, a water content or the like, work as critical
factors.
[0014] Therefore, if the lubricant used for the reciprocating
compressor compressing the natural refrigerant is not well
harmonized with the refrigerant of the refrigerator, the oil would
be leaked. Then, oil circulation is deteriorated to degrade a heat
transfer performance of the refrigerator and a lubrication
performance, resulting in that frictional portions of each motional
part are abraded and thus each part is damaged.
DISCLOSURE OF THE INVENTION
[0015] Therefore, it is an object of the present invention to
provide a reciprocating compressor that is capable of improving a
lubrication performance by using a lubricant in good harmony with a
natural refrigerant used for a refrigerator, and thus enhancing a
performance of a reciprocating compressor.
[0016] To achieve these objects, there is provided a reciprocating
compressor for compressing a refrigerant including: a hermetic
container to which a suction pipe and a discharge pipe are
connected; a driving unit having a stator fixed inside the hermetic
container and a mover disposed spaced apart from the stator and
linearly and reciprocally moved according to an interaction with
the stator; an organic compound refrigerant sucked into the suction
pipe, having an combustibility and explosiveness and consisting of
only carbon and hydrogen; a compression unit for receiving a
reciprocal motional force of the driving unit and making a
compression operation on the organic compound refrigerant; and a
mineral-based lubricant filled at a lower portion of the hermetic
container; and a lubrication unit for supplying the mineral-based
lubricant to each motional portion of the driving unit and the
compression unit and performing a lubricating operation.
[0017] In the reciprocating compressor of the present invention,
the stator consists of an outer stator fixed at the hermetic
container; an inner stator disposed with a certain air gap with an
inner circumferential surface of the outer stator; and a winding
coil wound at one of the outer stator and the inner stator, to
which power is applied from an external source, and the mover
consists of magnets disposed at regular intervals between the outer
stator and the inner stator and being linearly and reciprocally
moved when power is applied to the winding coil; and a magnet frame
having the magnets mounted thereon and transmitting a linear and
reciprocal motional force to the compression unit.
[0018] In the reciprocating compressor of the present invention,
the compression unit includes: a piston connected to the mover and
linearly and reciprocally moved; a cylinder, into which the piston
is slidably inserted, for forming a certain compression chamber; a
suction valve mounted at a refrigerant passage formed at the piston
and preventing a backflow of the refrigerant after being introduced
into the compression chamber; and a discharge valve mounted at the
front side of the cylinder and performing an opening and closing
operation on the compressed refrigerant.
[0019] In the reciprocating compressor of the present invention,
the lubrication unit includes: a lubricant pumping unit for pumping
the lubricant filled as much as a certain amount at a lower portion
of the hermetic container; and a lubricant supply passage for
supplying the lubricant pumped by the lubricant pumping unit to a
frictional portion between the piston and the cylinder.
[0020] In the reciprocating compressor of the present invention,
the refrigerant is isobutane (R600a) which is hydrocarbon-based and
has a molecular formula of CH(CH.sub.3).sub.3.
[0021] In the reciprocating compressor of the present invention,
the lubricant is a paraffin-based lubricant.
[0022] In the reciprocating compressor of the present invention,
the lubricant has a density of 0.866.about.0.880 g/cm.sup.3 at a
temperature of 15.degree. C. and a flash point of above 140.degree.
C.
[0023] In the reciprocating compressor of the present invention,
the lubricant has a kinematic viscosity of 7.2.about.21.8
mm.sup.2/s at a temperature of 40.degree. C. and a viscosity index
of 73.about.99.
[0024] In the reciprocating compressor of the present invention,
the lubricant has a flow point of below -25.degree. C. and a total
acid number of below 0.01 mgKOH/g.
[0025] In the reciprocating compressor of the present invention,
the lubricant has a water content of below 20 ppm and a breakdown
voltage of above 30 kV.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a sectional view of a general reciprocating
compressor for compressing a refrigerant.
MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS
[0027] FIG. 1 is a sectional view of a general reciprocating
compressor for compressing a refrigerant.
[0028] As shown in FIG. 1, the general reciprocating compressor
includes: a hermetic container 6 to which a suction pipe 2 for
sucking a refrigerant and a discharge pipe 4 for discharging a
compressed refrigerant are connected, a driving unit 8 disposed
inside the case 6 and generating a reciprocal motional force; a
compression unit 10 for receiving a reciprocal motional force
generated from the driving unit 8 and performing a compressing
operation on the refrigerant; and a lubrication unit 12 for
performing a lubricating operation on each motional portion of the
driving unit 8 and the compression unit 10.
[0029] The driving unit 8 includes: a cylindrical outer stator 16
fixed by a support frame 14 fixed inside the hermetic container 6;
an inner stator 18 disposed with a certain air gap with an inner
circumferential surface of the outer stator 16; a winding coil 20
wound at the outer stator 16, to which power is applied from an
external source; and magnets 22 disposed at regular intervals
between the outer stator 16 and the inner stator 18 and linearly
and reciprocally moved when power is applied to the winding coil
20.
[0030] The magnets 22 are fixed at an outer circumferential surface
of the magnet holder 24 at equal intervals, and the magnet holder
24 is connected to the piston 26 of the compression unit 10.
[0031] The compression unit 10 includes a piston 26 connected to
the magnet holder 24 and linearly and reciprocally moved; a
cylinder 28, into which the piston 26 is slidably inserted, forming
a compression chamber 36; a suction valve 32 mounted at a suction
opening 30 formed at the piston 26 and preventing a backflow of the
refrigerant after being introduced into the compression chamber 36;
and a discharge valve 34 mounted at a front side of the cylinder 28
and performing an opening and closing operation on a compressed
refrigerant.
[0032] The lubrication unit 12 includes: a lubricant 50 filled as
much as a certain amount at a lower portion of the hermetic
container; a lubricant pumping unit 40 for pumping the lubricant
50; and a lubricant supply passage 42 for supplying the lubricant
50 pumped by the lubricant pumping unit 40 to a frictional portion
between the piston 26 and the cylinder 28.
[0033] The operation of the general reciprocating compressor
constructed as described above will now be explained.
[0034] When power is applied to the winding coil 20, a flux is
formed around the winding coil 2, a flux is formed around the
winding coil 20, forming a closed loop along the outer stator 16
and the inner stator 18. By the interaction of the flux formed
between the outer stator 16 and the inner stator 18 and the flux
formed by the magnet 22, the magnet 22 is linearly moved in an
axial direction. When the direction of a current applied to the
winding coil 20 is changed in turn, the magnet 22 is linearly and
reciprocally moved as the direction of the flux of the winding coil
20 is changed.
[0035] Then, as the motion of the magnet 22 is transferred to the
piston 26 by the magnet holder 24, the piston 26 is linearly and
reciprocally moved inside the cylinder 28, thereby compressing a
refrigerant.
[0036] That is, when the piston 26 is retreated, the refrigerant is
supplied to the compression chamber 36 through the suction opening
30 formed at the piston 26.
[0037] When the piston 26 advances, the suction opening 30 is
closed by the suction valve 32 and the refrigerant inside the
compression chamber 36 is compressed, which is then discharged
through the discharge pipe 4.
[0038] The lubricant 50 filled in the hermetic container 6 is
pumped by the operation of the lubricant pumping unit 40 and
supplied to the frictional portion between the piston 26 and the
cylinder 28 through the lubricant supply passage 42, thereby
performing a lubricating operation.
[0039] The refrigerant compressed by the reciprocating compressor
constructed and operated as described above is a natural
refrigerant which is environment-friendly and has combustibility
and explosiveness.
[0040] As the natural refrigerant, an organic compound refrigerant
consisting of only carbon and hydrogen is mainly used. Among
organic compound refrigerants, hydrocarbon, consisting of only
carbon and hydrogen, has no toxicity, is chemically stable, has a
zero ozone depletion potential and a very low global warming index.
Hydrocarbon includes R50 (methane), R170 (ethane), R290 (propane),
R600 (butane), R600a (isobutene), R1270 (prophylene), etc.
[0041] Especially, isobutene (R600a) is hydrocarbon-based, has a
molecular formula of CH (CH3)3, and is environment-friendly natural
gas which does neither damage an ozone layer nor affect a
greenhouse effect, and as such it is used as a refrigerant
compressed by the reciprocating compressor of the present
invention.
[0042] As the lubricant 50 for making a lubricating operation for
the reciprocating compressor of the present invention, a mineral
oil is used which has a favorable compatibility with hydrocarbon
and satisfies physical and chemical characteristics.
[0043] The mineral oil is divided into a paraffin-based one and a
naphtan-based one. In the present invention, the paraffin-based
mineral lubricant is used.
[0044] It is preferred that the paraffin-based lubricant has a
density of 0.866.about.0.880 g/cm.sup.3 at a temperature of
15.degree. C.
[0045] A flash point of the paraffin-based lubricant varies
depending on a size and a type of the reciprocating compressor.
Preferably, it is above 140.degree. C., and it can be below
165.degree. C., below 175.degree. C., below 185.degree. C. and
below 200.degree. C. according to the type of an adopted
compressor.
[0046] A kinematic viscosity of the paraffin-based lubricant is
preferably 7.2.about.21.8 mm.sup.2/s at a temperature of 40.degree.
C., and most preferably, it is 8.29 mm.sup.2/s and 10.3 mm.sup.2/s
depending on the size and type of an adopted reciprocating
compressor.
[0047] A viscosity index of the paraffin-based lubricant is
preferably 73.about.99.
[0048] A flow point of the paraffin-based lubricant is preferably
below -25.degree. C.
[0049] A total acid number of the paraffin-based lubricant is below
0.01 mgKOH/g.
[0050] The total acid number of the lubricant, representing an
amount of an acid component contained in an oil, indicates an
amount of potassium hydroxide required for neutralizing an acid
component contained in 1 g of sample oil by the number of mg.
[0051] A water content of the paraffin-based lubricant is
preferably below 20 ppm.
[0052] A breakdown voltage of the paraffin-based lubricant is
preferably above 30 kV.
[0053] As so far described, the reciprocating compressor for
compressing a refrigerator of the present invention has such an
advantage that since it uses the paraffin-based lubricant, a sort
of the mineral oil with an excellent compatibility with the
hydrocarbon, a natural refrigerant, compressed by the reciprocating
compressor, the lubricating performance is improved and a life span
of the reciprocating compressor is lengthened.
[0054] It will be apparent to those skilled in the art that various
modifications and variations can be made in the reciprocating
compressor of the present invention without departing from the
spirit or scope of the invention. Thus, it is intended that the
present invention cover modifications and variations of this
invention provided they come within the scope of the appended
claims and their equivalents.
* * * * *