U.S. patent application number 14/624970 was filed with the patent office on 2015-06-11 for heat pump unit.
The applicant listed for this patent is MAYEKAWA MFG. CO., LTD.. Invention is credited to Hideaki SATO, Kazuya YAMADA, Atsushi YAMAMOTO.
Application Number | 20150159919 14/624970 |
Document ID | / |
Family ID | 53270778 |
Filed Date | 2015-06-11 |
United States Patent
Application |
20150159919 |
Kind Code |
A1 |
SATO; Hideaki ; et
al. |
June 11, 2015 |
HEAT PUMP UNIT
Abstract
To prevent the decline in the volumetric efficiency and the
decline in the performance of the heat pump having the
reciprocating compressor integrated therein by decreasing the
temperature of discharge gas in the reciprocating compressor with a
simple construction, a heat pump unit 1 constituting a heat pump
cycle in which the reciprocating compressor 3, a condenser 5, an
expansion valve 7 and an evaporator 8 are interposed in a
refrigerant circulating path 2,comprises a refrigerant-liquid
returning path 9 for returning a portion of the refrigerant liquid
having been condensed by the condenser 5 to a discharge chamber
provided in a cylinder top assembly 20 of the reciprocating
compressor 3 so that a portion of the refrigerant liquid is
supplied to the discharge chamber 36 via the refrigerant-liquid
returning path 9 and a discharge gas passageway 36a is cooled by
evaporative latent heat of the refrigerant liquid.
Inventors: |
SATO; Hideaki; (Koto-ku,
JP) ; YAMAMOTO; Atsushi; (Koto-ku, JP) ;
YAMADA; Kazuya; (Koto-ku, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MAYEKAWA MFG. CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
53270778 |
Appl. No.: |
14/624970 |
Filed: |
February 18, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12712553 |
Feb 25, 2010 |
|
|
|
14624970 |
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Current U.S.
Class: |
62/498 |
Current CPC
Class: |
F25B 2400/13 20130101;
F25B 30/02 20130101; F25B 31/008 20130101; F25B 1/005 20130101;
F04B 39/062 20130101; F25B 2400/23 20130101; F04B 53/08 20130101;
F25B 1/10 20130101; F25B 1/02 20130101 |
International
Class: |
F25B 1/00 20060101
F25B001/00; F25B 30/02 20060101 F25B030/02 |
Claims
1. A heat pump unit comprising: a heat pump cycle which includes a
reciprocating compressor having a compression part where a piston
reciprocates inside a cylinder, a condenser, an expansion valve,
and an evaporator provided in a refrigerant circulating path in
which NH.sub.3 refrigerant liquid is circulated; and a first
returning path for the refrigerant liquid which returns a portion
of the NH.sub.3 refrigerant liquid having been condensed in the
condenser to a discharge chamber provided in a cylinder top
assembly of the reciprocating compressor or a discharge area that
is in communication with the discharge chamber, wherein the
discharge chamber or the discharge area is provided with an
injection nozzle connected to the first returning path for the
refrigerant liquid such that the NH.sub.3 refrigerant liquid is
discharged through the injection nozzle to the discharge chamber or
the discharge area.
2. The heat pump unit according to claim 1, further comprising a
liquid pump and a pressure-regulating valve located in the first
returning path for the refrigerant liquid, and the NH.sub.3
refrigerant liquid which has higher pressure than the discharge
chamber is discharged through the injection nozzle to the discharge
chamber or the discharge area.
3. The heat pump unit according to claim 1, wherein the
reciprocating compressor is a single-stage compressor provided with
the injection nozzle in the discharge chamber or the discharge area
of the single-stage compressor.
4. The heat pump unit according to claim 1, wherein the
reciprocating compressor is a multi-stage compressor including an
upper stage compression part and a lower stage compression part,
and the injection nozzle is located in the discharge chamber or the
discharge area of the upper stage compression part so as to inject
the NH.sub.3 refrigerant liquid through the injection nozzle to the
discharge chamber or discharge area of the upper stage compression
part.
5. The heat pump unit according to claim 4, further comprising: a
second returning path for the refrigerant liquid which returns the
portion of the NH.sub.3 refrigerant liquid having been discharged
from the upper stage compressor part and then condensed in the
condenser, to the discharge chamber or discharge area that is in
communication with the discharge chamber, the discharge chamber or
the discharge area being located in the lower stage compression
part; wherein the portion of the NH.sub.3 refrigerant liquid is led
to be returned to the discharge chamber or discharge area of the
lower stage compression part via the second returning path.
6. The heat pump unit according to claim 5, further comprising a
heat exchanger for the refrigerant liquid which is provided in the
refrigerant circulating path between the condenser and the
expansion valve, the heat exchanger being connected to the
refrigerant circulating path so that refrigerant gas discharged
from the lower stage compressor is introduced to the intake chamber
or intake area of the upper stage compressor through the heat
exchanger, the refrigerant liquid from the condenser being cooled
with the refrigerant gas discharged from the lower stage
compressor.
7. The heat pump unit according to claim 6, further comprising a
heat exchanger for the refrigerant liquid provided in the
refrigerant circulating path in an upstream side of the second
returning path, wherein a portion of the refrigerant liquid having
been cooled in the heat exchanger is supplied to the first or
second returning path.
8. The heat pump unit according to claim 1, wherein the
reciprocating compressor is for refrigerant and comprises an intake
chamber in communication with a cylinder via an intake valve at a
cylinder top assembly and a discharge chamber in communication with
the cylinder via a discharge valve, wherein the injection nozzle
and a supply port for refrigerant liquid are arranged in the
discharge chamber or discharge area, and the injection nozzle is
connected to the supply port for the refrigerant liquid, and
wherein the refrigerant liquid is injected through the injection
nozzle to the discharge chamber or discharge area.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of prior
application Ser. No. 12/712,553, filed on Feb. 25, 2010, the
disclosure of which, in its entirety, including the drawings,
claims, and the specification, is incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention relates to a heat pump unit and a
reciprocating compressor which avoids temperature rise of
refrigerant gas being discharged from the reciprocating compressor
integrated in a heat pump unit such as a refrigeration unit so as
to improve volumetric efficiency of the reciprocating compressor
and further enhance capacity of the heat pump unit. The present
invention also relates to a heat pump unit (including a
refrigeration unit) using a reciprocating type compressor for
NH.sub.3 which is applicable to all kinds of reciprocating
compressors regardless of whether it is a single-stage compressor
or a two-stage compressor.
DESCRIPTION OF THE RELATED ART
[0003] A reciprocating type compressor that compresses gas by
alternately opening and closing an intake valve and a discharge
valve provided in a cylinder head or an upper part of a cylinder
(hereinafter referred as a cylinder top assembly) by reciprocating
the piston in the cylinder is well known in the art. Such
reciprocating type compressor includes a single-stage reciprocating
compressor in which gas drawn into the cylinder by the intake valve
is compressed in a single stage and the compressed gas is
discharged from the discharge valve, and a two-stage reciprocating
compressor in which a compressing part thereof comprising the
piston reciprocating in the cylinder includes a lower stage and an
upper stage so that the gas compressed at the lower stage is
further compressed at the upper stage. It is common that both the
single-stage and the two-stage reciprocating compressors are
provided with an intake gas passageway as well as a discharge gas
passageway in a casing comprising a cylinder block. It is common in
conventional cases to provide an intake gas passageway and a
discharge gas passageway inside a casing thereof. In the
reciprocating compressor integrated in the heat pump unit such as
the refrigeration unit, heat exchange happens via a wall surface
between discharge gas of high temperature and intake gas of low
temperature and thus the temperature of the intake gas rises before
being drawn into a cylinder. Therefore, the intake gas expands
before reaching the cylinder and specific volume thereof becomes
bigger and circulating mass flow decreases significantly. This
brings decreased volumetric efficiency in the compressor and
decline in cooling capacity of the refrigeration device in which
the reciprocating compressor is integrated, or heating capacity of
the heat pump unit.
[0004] Especially, ammonia gas has a relatively-high ratio of
specific heat with such characteristics that the discharge
temperature is high and the specific volume becomes larger as shown
in FIG. 11. When using this type of refrigerant, it is necessary to
suppress the heating (temperature rise) of the intake gas inside
the casing of the compressor.
[0005] Patent Reference 1 P2000-18154A) discloses a means to
suppress excessive temperature rise in the cylinder during the
compression and to eliminate the problem of the deterioration of
the lubricant and seizing. This means has cavities at the periphery
of the cylinder and by introducing returning refrigerant (cooling
medium) returning from an accumulator to the cavities so as to cool
a cylinder room. The returning refrigerant passes the cavities and
then leads to the intake chamber through communication holes.
[0006] [Patent Reference 1] JP2000-18154A
DISCLOSURE OF THE INVENTION
Problems to be Solved
[0007] The means disclosed in Patent Reference 1 cools the cylinder
by introducing the returning cooling media to the cavities provided
at the periphery of the cylinder. Therefore, as the discharge gas
is not cooled, there is heat exchange between the intake gas and
the discharge gas via the wall surface of the casing and the
temperature of the intake gas before reaching the cylinder
inevitably rises. This brings decreased volumetric efficiency in
the compressor and decline in cooling capacity of the refrigeration
device in which the reciprocating compressor is integrated, or
heating capacity of the heat pump unit.
[0008] Moreover, the cavities to which the refrigerant is
introduced are provided around the cylinder room, resulting in a
larger and heavier compressor, and a large amount of refrigerant is
introduced to the cavities, resulting in decreasing the capacity of
the heat pump device such as refrigeration device with the
compressor.
[0009] In view of the problems above, embodiments of the present
invention provide a heat pump unit (including a refrigeration unit)
that prevents the temperature rise of the intake gas before being
drawn into the cylinder, the heat pump unit being applicable to all
kinds of reciprocating compressors for NH.sub.3 regardless of
whether it is a single-stage compressor or a two-stage compressor.
In view of the problems above, embodiments of the present invention
prevent the decline in the volumetric efficiency of the
reciprocating compressor and the decline in the performance of the
heat pump having the reciprocating compressor integrated therein by
decreasing the temperature of the discharge gas in the
reciprocating compressor with a simple construction.
[0010] Specifically, embodiments of the present invention provide a
high-efficient heat pump device and refrigeration device using a
reciprocating compressor in which cooling water is not used, the
heating of the intake gas being suppressed, and the cooling
capacity (volumetric efficiency) being improved.
Means to Solve the Problems
[0011] To solve the problem above, a heat pump of the present
invention, is constructed so that the refrigerant liquid (condensed
liquid) is injected to a refrigerant gas space of high temperature
of the discharge side (discharge chamber or discharge area in
communication with the discharge chamber) of the compressor so as
to lower the temperature of the refrigerant gas being discharged,
and comprises:
[0012] a heat pump cycle which includes a reciprocating compressor,
a condenser, an expansion valve and an evaporator provided in a
refrigerant circulating path: and
[0013] a first returning path for refrigerant liquid which returns
a portion of the refrigerant liquid having been condensed in the
condenser to a discharge chamber provided in a cylinder top
assembly of the reciprocating compressor or a discharge area that
is in communication with the discharge chamber,
[0014] wherein the portion of the refrigerant liquid is returned to
the discharge chamber or discharge area via the first returning
path so as to cool the discharge chamber or discharge area by
evaporative latent heat of the refrigerant liquid.
[0015] The heat pump unit of the present invention is constructed
to return a portion of the refrigerant liquid having been condensed
in the condenser to the discharge chamber provided in the cylinder
top assembly of the reciprocating compressor or the discharge area
that is in communication with the discharge chamber. The
refrigerant liquid is evaporated by the heat from the discharge gas
in the discharge room or discharge area, and taking the evaporative
latent heat from the discharge gas, thereby cooling the discharge
chamber or discharge area. By cooling the discharge chamber or
area, the heat transfer from the discharge chamber or area to the
intake chamber or to the gas passageway is suppressed.
[0016] By this, the temperature rise of the refrigerant gas before
being introduced to the cylinder is prevented, thereby suppressing
the volume expansion and preventing the decline in the volumetric
efficiency of the reciprocating compressor and the decline in the
performance of the heat pump having the reciprocating compressor
integrated therein.
[0017] In this manner, as the discharge chamber or discharge area
being in communication with the discharge chamber is cooled by the
evaporative latent heat of the refrigerant and there is no need for
cooling water or the like, it is possible to use the heat pump in
the desert or other places where the cooling water is hard to get.
And this is very inexpensive and causes no damage to the
environment.
[0018] The heat pump of the present invention preferably further
comprises an injection nozzle which is arranged in the discharge
chamber or discharge area and is connected to the first returning
path for the refrigerant liquid,
[0019] wherein the refrigerant liquid is injected through the
injection nozzle to the discharge chamber or discharge area. By
this the evaporation of the refrigerant liquid at the discharge
chamber or discharge area is promoted, thereby improving the
cooling effect.
[0020] It is preferable in the heat pump unit of the present
invention that the reciprocating compressor includes an upper stage
compressor and a lower stage compressor, the first returning path
for the refrigerant liquid returns the portion of the refrigerant
liquid which have been discharged from the upper stage compressor
and then condensed in the condenser, to the discharge chamber of
the lower stage compressor or the discharge area that is in
communication with the discharge chamber, and the portion of the
refrigerant liquid is returned to the discharge chamber or
discharge area of the lower stage compressor via the first
returning path.
[0021] The refrigerant having been discharged from the upper stage
compressor and then condensed in the condenser has higher pressure
than the discharge chamber or discharge area of the lower stage
compressor, and thus the refrigerant can be supplied to the
discharge chamber or discharge area of the lower stage compressor
without using an intensifier. Therefore, this pump unit does not
require a power source or device for supplying the refrigerant
liquid.
[0022] In addition to the configurations as described above, it is
also preferable that the pump unit further comprises:
[0023] a second returning path for the refrigerant liquid which
returns the portion of the refrigerant liquid having been
discharged from the upper stage compressor and then condensed in
the condenser, to the discharge chamber or discharge area; and
[0024] a pressure booster which is provided in the second returning
path,
[0025] wherein the portion of the refrigerant liquid is returned to
the discharge chamber or discharge area of the upper stage
compressor via the second returning path.
[0026] When the portion of the refrigerant liquid is returned to
the discharge chamber or discharge area of the upper stage
compressor, a pressure booster such as a liquid pump needs to be
provided in the returning path as the pressure booster and the
discharge chamber or area of the upper stage compressor have the
same pressure.
[0027] By this, the intake gas of the lower stage compressor and
the upper stage compressor can be cooled.
[0028] The heat pump unit of the present invention preferably
further comprises a heat exchanger for the refrigerant liquid which
is provided in the refrigerant circulating path between the
condenser and the expansion valve, the heat exchanger being
connected to the refrigerant circulating path so that refrigerant
gas discharged from the lower stage compressor is introduced to the
intake chamber or intake area of the upper stage compressor through
the heat exchanger, the refrigerant liquid from the condenser being
cooled with the refrigerant gas discharged from the lower stage
compressor.
[0029] By this, the refrigerant liquid moving in the circulating
path from the condenser to the expansion valve is cooled by the
refrigerant gas having been discharged from the upper stage
compressor and having been cooled, thereby improving the
performance of the heat pump such as refrigeration unit.
[0030] It is preferable that the heat pump unit of the present
invention further comprises a heat exchanger for the refrigerant
liquid which is provided in the refrigerant circulating path
between the condenser and the expansion valve,
[0031] wherein the heat exchanger is connected to the refrigerant
circulating path so that refrigerant gas discharged from the lower
stage compressor is introduced to the intake chamber or intake area
of the upper stage compressor, the refrigerant liquid from the
condenser being cooled with the refrigerant gas discharged from the
lower stage compressor,
[0032] wherein the heat exchanger for the refrigerant liquid is
provided in the refrigerant circulating path in an upstream side of
the first or second returning path, and
[0033] wherein a portion of the refrigerant liquid having been
cooled in the heat exchanger is supplied to the first or second
returning path.
[0034] By this, the refrigerant having been cooled by the heat
exchanger can be supplied to the intake chamber or intake area of
the lower stage or upper stage compressor, thereby making the upper
stage compressor more effective in cooling the discharge gas.
[0035] It is preferable that the heat pump unit of the present
invention further comprises an intercooler which is provided in the
refrigerant circulating path between the condenser and the
expansion valve, the intercooler being connected to the refrigerant
circulating path so that refrigerant gas discharged from the lower
stage compressor is supplied to the intake chamber or intake area
of the upper stage compressor through the intercooler,
[0036] wherein a portion of the refrigerant liquid from the
condenser is evaporated in the intercooler so as to cool other
refrigerant liquid and the refrigerant gas discharged from the
lower stage compressor.
[0037] By this, the performance of the heat pump unit is enhanced
and the portion of the high-pressure refrigerant liquid having been
over-cooled by the intercooler is supplied to the intake chamber or
area of the lower stage compressor so as to improve the cooling
effect of the discharge gas of the lower stage compressor and
reduce the supply of the refrigerant liquid. Thus, the injection
nozzle provided in the discharge chamber or area of the lower stage
compressor can be downsized.
[0038] In the case of using NH.sub.3 which has high ratio of
specific heat as refrigerant, there is such characteristic that
when the temperature rises, the specific volume of NH.sub.3 gets
bigger than other types of refrigerant. The volume expansion of the
refrigerant due to the temperature rise of the intake gas before
reaching the cylinder is significant. However, with the present
invention, the temperature rise of NH.sub.3 before being introduced
to the cylinder is securely suppressed, thereby avoiding the
declined performance of the heat pump unit.
[0039] Next, a first reciprocating compressor of the present
invention that can be applied to the heat pump unit of the present
invention is a reciprocating compressor for refrigerant which is
equipped with an intake chamber connected to a cylinder via an
intake valve at a cylinder top assembly and a discharge chamber
connected to the cylinder via a discharge valve, the reciprocating
compressor comprising:
[0040] a supply port for refrigerant liquid which is provided in
the discharge chamber or a discharge area that is in communication
with the discharge chamber and through which a portion of the
refrigerant liquid obtained by condensing discharge gas is supplied
to the discharge chamber or discharge area,
[0041] wherein the supplied refrigerant liquid evaporates in the
discharge chamber or discharge area so that the discharge chamber
or discharge area is cooled by evaporative latent heat of the
refrigerant liquid.
[0042] With the configuration described above, the portion of the
refrigerant liquid obtained from condensing the discharge gas is
supplied to the discharge chamber or area, thereby cooling the
discharge chamber or area by the evaporative latent heat of the
refrigerant liquid. Consequently the temperature rise in the
discharge chamber or area is diminished and the temperature rise of
the intake gas before being introduced to the cylinder is
prevented. Thus, the increase of the specific volume of the intake
gas is suppressed and the declined volumetric efficiency is
avoided.
[0043] In the first reciprocating compressor of the present
invention, the compressor further comprises an injection nozzle
which is arranged in the discharge chamber or discharge area and is
connected to the supply port for the refrigerant liquid,
[0044] wherein the refrigerant liquid is injected through the
injection nozzle to the discharge chamber or discharge area.
[0045] By this, the evaporation of the refrigerant liquid in the
discharge chamber or area is enhanced, thereby improving the
cooling effect of the refrigerant liquid.
[0046] Moreover, a second reciprocating compressor of the present
invention that can be applied to the heat pump unit of the present
invention for refrigerant which is equipped with an intake chamber
connected to a cylinder via an intake valve at a cylinder top
assembly and a discharge chamber connected to the cylinder via a
discharge valve, is unique in that a heat insulating material is
interposed between the intake chamber and the discharge chamber so
as to suppress heat transfer between the intake chamber and
discharge chamber.
[0047] With the configuration described above, by simply
interposing a heat insulating material between the intake chamber
and the discharge chamber, the heat transfer between the intake
chamber and discharge chamber is prevented. Consequently, the
temperature rise of the refrigerant gas before reaching the
cylinder is prevented, thereby suppressing the increase of the
specific volume of the refrigerant gas and suppressing the decline
in the volumetric efficiency. Thus, the performance of the heat
pump unit integrating the reciprocating compressor is
maintained.
[0048] Furthermore, by combining the first reciprocating compressor
and the second reciprocating compressor, it is possible to suppress
the heat transfer from the discharge chamber to the intake chamber
in a synergistic manner.
[0049] Specifically, the supply port is provided in the discharge
chamber or area for receiving the portion of the refrigerant gas
obtained by condensing the discharge gas is provided; the
refrigerant liquid is supplied to the discharge chamber or area via
the supply port; the discharge chamber or area is cooled by the
evaporative latent heat of the refrigerant liquid; and the
insulating material is interposed between the discharge chamber and
intake chamber so as to effectively suppress the heat transfer from
the discharge chamber to the intake chamber.
[0050] In the first or second reciprocating compressor of the
present invention, it is preferable that
[0051] the cylinder top assembly comprises: a closure plate which
closes the cylinder so as to form a discharge gas passage and
having the discharge valve at the discharge gas passage; a head
cover which covers over the closure plate so as to form the
discharge chamber; a valve plate which is arranged under the
closure plate so as to enclose the cylinder and in which the intake
valve is provided; a cylinder exterior body which is arranged under
the valve plate and forms the intake chamber, and
[0052] wherein an insulation gasket is interposed between the valve
plate and the cylinder exterior body,
[0053] wherein the valve plate and gasket are widen at edges
thereof so as to grip and hold outer edges of the valve plate and
the insulation gasket at a joint part of the head cover and the
cylinder exterior body from both sides.
[0054] With the configuration described above, the insulation
gasket can be easily fixed between the valve plate and the cylinder
exterior body. And by interposing the insulation gasket between the
valve plate and the cylinder exterior body, the blocking between
the intake chamber formed by the cylinder exterior body and the
discharge chamber formed above the closure plate is effectively
done.
[0055] Furthermore, when the cylinder exterior body encloses a
plurality of the cylinders, it is preferable to form an insulation
space between the cylinder exterior body and the gasket in an area
interposed by the cylinders. By this, the insulation effect can be
further enhanced.
Effect of the Present Invention
[0056] With the heat pump unit of the present invention comprising
a heat pump cycle which includes a reciprocating compressor, a
condenser, an expansion valve and an evaporator provided in a
refrigerant circulating path: and a first returning path for
refrigerant liquid which returns a portion of the refrigerant
liquid having been condensed in the condenser to a discharge
chamber provided in a cylinder top assembly of the reciprocating
compressor or a discharge area that is in communication with the
discharge chamber, wherein the portion of the refrigerant liquid is
returned to the discharge chamber or discharge area via the first
returning path so as to cool the discharge chamber or discharge
area by evaporative latent heat of the refrigerant liquid, the heat
transfer from the discharge chamber or area to the intake chamber
or area of the reciprocating compressor is suppressed and the
temperature rise and volume expansion of the intake gas before
being introduced to the cylinder is suppressed, and the volumetric
effect of the reciprocating compressor is prevented from declining.
By this, even when the refrigerant with high specific volume such
as NH.sub.3 is used, the performance of the heat pump unit is
maintained. Furthermore, by not using the cooling water, it is
possible to use the heat pump in the desert or other places where
the cooling water is hard to get. And this is very inexpensive and
causes no damage to the environment.
[0057] With the first reciprocating compressor of the present
invention for refrigerant which is equipped with an intake chamber
connected to a cylinder via an intake valve at a cylinder top
assembly and a discharge chamber connected to the cylinder via a
discharge valve, the reciprocating compressor comprising: a supply
port for refrigerant liquid which is provided in the discharge
chamber or a discharge area that is in communication with the
discharge chamber and through which a portion of the refrigerant
liquid obtained by condensing discharge gas is supplied to the
discharge chamber or discharge area, wherein the supplied
refrigerant liquid evaporates in the discharge chamber or discharge
area so that the discharge chamber or discharge area is cooled by
evaporative latent heat of the refrigerant liquid, the heat
transfer from the discharge chamber or area to the intake chamber
or area of the reciprocating compressor is suppressed and the
temperature rise and volume expansion of the intake gas before
being introduced to the cylinder is suppressed, and the volumetric
effect of the reciprocating compressor is prevented from declining.
And by applying this to the aforementioned heat pump unit of the
present invention, it is possible to maintain the performance of
the heat pump unit.
[0058] With the second reciprocating compressor of the present
invention that can be applied to the heat pump unit of the present
invention for refrigerant which is equipped with an intake chamber
connected to a cylinder via an intake valve at a cylinder top
assembly and a discharge chamber connected to the cylinder via a
discharge valve, wherein a heat insulating material is interposed
between the intake chamber and the discharge chamber so as to
suppress heat transfer between the intake chamber and discharge
chamber, the heat transfer from the discharge chamber or area to
the intake chamber or area of the reciprocating compressor is
suppressed with a simple means and the effects similar to that of
the first reciprocating compressor of the present invention is
obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
[0059] FIG. 1 is a system diagram of a refrigeration unit relating
to first embodiment of the present invention.
[0060] FIG. 2 is an elevation plan of a cylinder top assembly of
the reciprocating compressor to be integrated in the refrigeration
unit of the first embodiment.
[0061] FIG. 3 is a perspective interior elevation of the cylinder
top assembly of the reciprocating compressor of the first
embodiment.
[0062] FIG. 4 is a system diagram of a refrigeration unit relating
to second embodiment of the present invention.
[0063] FIG. 5 is a system diagram of a refrigeration unit relating
to third embodiment of the present invention.
[0064] FIG. 6 is a system diagram of a refrigeration unit relating
to fourth embodiment of the present invention.
[0065] FIG. 7 is a system diagram of a refrigeration unit relating
to fifth embodiment of the present invention.
[0066] FIG. 8 is a system diagram of a refrigeration unit relating
to sixth embodiment of the present invention.
[0067] FIG. 9 is an elevation plan of a cylinder top assembly of
the reciprocating compressor to be integrated in the refrigeration
unit of a seventh embodiment.
[0068] FIG. 10 is a system diagram of a refrigeration unit relating
to an eighth embodiment of the present invention.
[0069] FIG. 11 is a graph showing the change of specific volume of
ammonia gas.
[0070] FIG. 12 is a system diagram of a refrigeration unit relating
to ninth embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0071] Hereafter, the present invention will be described in detail
with reference to the embodiments shown in the figures. However,
the dimensions, materials, shape, the relative placement and so on
of a component described in these embodiments shall not be
construed as limiting the scope of the invention thereto, unless
especially specific mention is made.
First Embodiment
[0072] A first embodiment of the present invention which is applied
to the refrigeration unit is explained in reference to FIG. 1 to
FIG. 3. FIG. 1 is a system diagram of a refrigeration unit relating
to first embodiment of the present invention (a reciprocating
compressor 3 being a single-stage compressor).
[0073] In FIG. 1 a refrigeration unit 1 is equipped with a
refrigerant circulating passageway for refrigerant MH.sup.3, and on
the passageway the reciprocating compressor 3, from there down, an
oil separator 4, a condenser 5, a liquid receiver 6, an expansion
valve 7, an evaporator 8 are interposed so as to configure a
cooling cycle.
[0074] The reciprocating compressor 3 has a discharge chamber 303
being connected to the cylinder 301 via a discharge valve 302 and
an intake chamber 305 being connected to the cylinder via a intake
valve 304. The discharge chamber 303 is provided at an immediate
exit side of the discharge valve 302 and being connected to the
refrigerant circulating passageway 2. The intake chamber 305 is
provided at an immediate exit side of the intake valve and being
connected to the refrigerant circulating passageway 2. The
refrigerant gas having been compressed to high pressure in the
cylinder is discharged via the discharge valve 302 to the discharge
chamber 303.
[0075] The refrigerant gas having been discharged from the
discharge chamber to the refrigerant circulating passageway 2 is
passed through the oil separator 4 so as to separate lubricant oil,
and then is sent to the condenser 5 so as to promote heat loss and
condense the refrigerant gas. The condensed refrigerant gas is
temporarily stored in the evaporator 8 where evaporative latent
heat is absorbed from a load. Subsequently, the refrigerant gas is
introduced to the intake chamber 305 of the reciprocating
compressor 3 and then to the cylinder 301 via the intake valve 304.
The temperatures shown at each part on the circulating passageway
in FIG. 1 are the temperatures of the refrigerant (NH3) at those
parts.
[0076] In the embodiment, a branching path 9 for diverging the
refrigerant liquid from the refrigerant circulating passageway in
the downstream of the liquid receiver 6 is provided. The branching
path 9 is connected to an injection nozzle 306 located on an inner
wall of the discharge chamber 303. A liquid pump 11 and a
pressure-regulating valve 12 located in the downstream side of the
liquid pump are interposed in the branching path 9. A portion of
the refrigerant liquid passes through the branching path 9 so as to
adjust the pressure thereof by the rotation speed control of the
liquid pump 11, and the pressure-regulating valve 12, becoming
high-pressure in the discharge chamber 303, and being sprayed from
the injection nozzle 306 into the discharge chamber 303. The
refrigerant liquid having been injected into the discharge chamber
303 evaporates while absorbing evaporative latent heat if the
refrigerant gas in the discharge chamber 303.
[0077] In this manner, the heat transfer from the discharge chamber
to the intake chamber is suppressed so as to lower the temperature
inside the discharge chamber. Thus, the temperature rise of the
refrigerant gas before being introduced into the cylinder 301 is
suppressed.
[0078] In the embodiment, an air condensing apparatus is used for
the condenser 5 and a high pressure type or expansion type oil
cooler (not shown in the drawings) is used for cooling the
lubricant oil of the reciprocating compressor 3 so that a high
efficient heat pump unit or refrigeration unit having the
reciprocating compressor which does not use cooling water is
achieved.
[0079] Moreover, it is also possible to arrange the liquid receiver
6 in an upstream side of the reciprocating compressor 3 in the
direction of gravitational force and provide a liquid head so as to
omit the liquid pump 11 (this can be applied to other embodiments
described below)
[0080] FIG. 2 and FIG. 3 illustrate detailed constructions of a
cylinder top assembly of the reciprocating compressor 3. The
reciprocating compressor 3 of the present embodiment has two
cylinders.
[0081] In FIG. 2, a piston 22 is slidably positioned in the
cylinder 21. The cylinder 21 is placed on an exterior body 23. On
top of the cylinder exterior body 23, a valve plate 31 is
positioned which has openings 31a. The openings 31a are positioned
to correspond to the top opening of the cylinders 21. The valve
plate 31 has cavities in which the plate-type intake valve 25
forming a ring shape and a volute spring 26 on top of the intake
valve are housed.
[0082] An elastic force of the volute spring 26 works on the intake
valve 25 so as to press the intake valve 25 against a valve seat 27
located on top of the cylinder 21. The intake chamber is located
under the intake valve and the intake chamber is in communication
with the cylinder 21 by lifting the intake valve 25 with the
refrigerant gas against the elastic force of the volute spring
working on the intake valve 25.
[0083] A valve cage 32 in a shape of circular plate is provided
above the valve plate 31 so as to close the opening 31a of the
valve plate 31. A valve plate 34 in a shape of a conical frustum is
joined to the bottom of the valve cage 32 with a bolt 33. A
positioning pin 35 is inserted in a positioning hole of the valve
plate 34 and a positioning hole of the valve cage 32 so as to
position the valve plate 34 in respect with the valve cage 32. The
valve plate 34 is shaped to fit in the top part of the piston 22
and when the piston 22 reaches the top limit of the cylinder 21,
there is no space in the cylinder.
[0084] A discharge gas passage 36a is formed in the valve cage 32
and the volute spring 37 is provided in the discharge gas
passageway 36a. Under the volute spring, a discharge valve 38 in a
shape of a ring plate is provided. Under the discharge valve 38, a
the valve seat 34a and another valve seat 31b integral with the
valve plate 31 are arranged. When the pressure of the discharge gas
of the cylinder 21 is small, the elastic force of the volute spring
37 works on the discharge valve 38 so as to press the discharge
valve 38 against the valve seats 34a and 31b, thereby closing the
discharge gas passageway 36a. When the piston 22 is lifted and the
pressure of the discharge gas becomes larger, the discharge gas
lifts the discharge valve 38 so as to open the discharge gas
passageway 36a.
[0085] A plate-like insulation gasket 39 made of insulation
material is interposed between the valve plate 31 and the cylinder
exterior body 23. Above the valve cage 32, a head cover 40 is
arranged so as to form a discharge chamber 36 on top of the valve
cage 32. The discharge chamber 36 is in communication with the
discharge gas passageway 36a and also feeds the high-pressure
discharge gas being discharged from the cylinder 21 to the
refrigerant circulating path 2. The branching path 9 is connected
to a through-bore 40a formed in the head cover, and an injection
nozzle 306 is provided in the opening of an inner wall of the head
cover. By this, the refrigerant liquid of the branching path 9 is
sprayed into the discharge chamber 36.
[0086] As shown in FIG. 3, a bolt seat 41 is arranged at the outer
edge of the head cover 40, and bolt holes 42, 43, 44 and 45 are
provided at the outer edge of the bolt seat 41, valve plate 31,
insulation gasket 39 and cylinder exterior body 23 respectively
which are integrally connected with bots not shown in the
drawings.
[0087] Moreover, in the present embodiment, the exterior body 23 of
the cylinder is constructed to include two cylinders. Thus, the
exterior body 23 has two openings 23a in which two cylinders are
fitted. And between the pair of the openings 23a, a depressed
portion 46 is provided so as to form an insulation space i between
the exterior body 23 and the insulation gasket 39.
[0088] In the reciprocating compressor of FIG. 2 and FIG. 3, the
piston 22 moves downward and thus forming low pressure in the
cylinder 21 and the intake gas g.sub.1 pushes up the intake valve
25 against the elastic force of the spring 26 so as to introduce
the intake gas g.sub.1 into the cylinder 21. Next the piston 22
moved upward and it becomes high pressure inside the cylinder, and
the discharge gas g.sub.2 pushes up the discharge valve 38 against
the elastic force of the volute spring 37 so as to discharge the
discharge gas g.sub.2 of high pressure to the discharge chamber 36
via the discharge gas passageway 36a.
[0089] When the reciprocating unit is housed in the refrigeration
unit 1, for instance, the temperature of the intake chamber 24 is
-20 to 0.degree. C., the intake pressure being 0.2 to 0.4 Mpa, the
temperature of the discharge chamber 36 being 120 to 140.degree. C.
and the discharge pressure being 1.3 to 1.6 Mpa.
[0090] The cylinder top assembly 20 is heated by the heated
discharge gas g.sub.2. However, in the present embodiment, the
refrigerant liquid is sprayed from the branching path 9 into the
discharge chamber 36 via the injection nozzle 306, the sprayed
refrigerant liquid cooling the discharge gas by the evaporative
latent eat of the discharge gas, and the insulation gasket 39 being
interposed between the valve plate and the cylinder exterior body
23 so as to suppress effectively the heat transfer from the
discharge gas g.sub.2 through the exterior body 23 to the intake
gas g.sub.1 moving through the intake chamber.
[0091] In this manner, the temperature rise of the intake gas
g.sub.1 before being introduced to the cylinder 21 is suppressed,
thereby inhibiting the volumetric expansion of the intake gas
g.sub.1. For instance, as shown in FIG. 1, the refrigerant liquid
of 35.degree. C. is injected to the injection nozzle 306 so as to
reduce the temperature of the discharge gas inside the discharge
chamber 303 to 50.degree. C. and reduce the temperature of the
intake gas inside the intake chamber 305 to -10.degree. C. Thus,
the volume expansion of the refrigerant gas being introduced to the
cylinder is prevented, thereby suppressing the decline of the
volumetric efficiency of the reciprocating compressor 3. In this
manner, the performance of the reciprocating compressor integrated
in the refrigeration unit 1 is maintained.
[0092] Especially, NH.sub.3 which is used as refrigerant has high
ratio of specific heat and the volume expansion due to the
temperature rise is significant and thus the decline of the
volumetric efficiency of the reciprocating unit becomes large.
However, with the present invention, the decline of the volumetric
efficiency of the reciprocating unit is suppressed and the
performance of the refrigeration unit 1 is sustained.
[0093] Moreover, in the present embodiment, the temperature of the
intake gas is suppressed by the evaporative latent heat of the
refrigerant liquid and the insulation gasket 19 and does not
require cooling water. Therefore, it is possible to use the heat
pump in the desert or other places where the cooling water is hard
to get. And this is very inexpensive and causes no damage to the
environment.
[0094] In the present embodiment, the refrigerant liquid is sprayed
to the discharge chamber 36 in a form of fine particles through the
injection nozzle 306 so as to improve the absorption effect of the
evaporative latent heat of the discharge gas. Moreover, the
insulation gasket 39 is installed from the intake chamber 24 to the
outer edge of the cylinder exterior body 23 so as to shut off the
heat of the discharge gas in a wide range where the insulation
gasket 39 is installed. Therefore, the heat transfer of the
discharge gas to the cylinder exterior body 23 is effectively
prevented.
[0095] Additionally, the insulation space i is provided in the
cylinder exterior body 23 and between the plural cylinders 21 so as
to improve the heat insulation effect.
Second Embodiment
[0096] Next, a second embodiment of the present invention (the
reciprocating compressors 3a, 3b are combined two stage compressor
or individual two stage compressors without an intercooler in the
refrigerant path 2a between a liquid receiver 6 and an expander 7
in the two-stage compression and the single-stage expansion) is
explained in reference to FIG. 4. In FIG. 4, a refrigeration unit 1
has a two-stage reciprocating compressor consisting of a lower
stage compressor 3a and an upper stage compressor 3b. The
configuration of the cylinder top assembly of the lower and upper
stage compressors 3a and 3b are the same as that of the compressor
of the first embodiment shown in FIG. 2 and FIG. 3.
[0097] The refrigerant liquid from the liquid receiver 6 passes
through the refrigerant circulating path 2a and reaches the
expansion valve 7. The refrigerant liquid is decompressed by the
expansion valve 7, the decompressed refrigerant liquid evaporating
in the evaporation unit 8 by taking the evaporative latent heat
from, and the evaporated refrigerant gas being introduced to the
intake chamber 305 of the lower stage compressor 3a. The
refrigerant gas being introduced to the intake chamber 305 is then
introduced to the cylinder 301 via the intake chamber 304 and
compressed in the cylinder 301.
[0098] The refrigerant gas being compressed in the cylinder 301 is
fed to the discharge chamber 303 via the discharge valve 302, and
then discharged from the discharge chamber 303 to the refrigerant
circulating path 2b. The refrigerant gas being discharged form the
refrigerant circulating path 2b is filtered in the oil separator 4a
so as to separate the lubricant oil and then introduced into the
intake chamber 305 of the upper stage compressor 3b.
[0099] The refrigerant gas being introduced to the intake chamber
305 of the upper stage compressor 3b is compressed in the cylinder
301 of the upper stage compressor 3b and then discharged form the
discharge chamber 303 to the circulating path 2c. The refrigerant
gas being discharged to the circulating path 2c is filtered by the
oil separator 4b so as to separate the lubricant oil and the
filtered refrigerant gas releases the heat and condensed in the
condenser 5.
[0100] In the present embodiment, a branching path 51 is provided
which branches from the refrigerant circulating path 2a in the
downstream side of the liquid receiver 6. In the branching path 51,
a liquid pump 52 and a pressure regulating valve 53 are provided.
The terminal of the branching path 51 is connected to the discharge
chamber of the upper stage compressor 3b. By the rotation speed
control of the liquid pump 52, and the pressure control of
pressure-regulating valve 53, the refrigerant liquid is pressurized
to a higher pressure than that of the discharge chamber 303 of the
upper stage compressor 3b and sprayed into the discharge chamber
303 via the injection nozzle 306.
[0101] Another branching path 54 branches from the circulating path
2a in the downstream side of the branching path 51 and the
branching path 54 is connected to the injection nozzle 306 provided
on the inner wall of the discharge chamber 303 of the lower stage
compressor 3a. Inside of the discharge chamber 303 of the lower
stage compressor 3a has a lower pressure than the branching path
54, and thus there is no need for increasing the pressure of the
refrigerant liquid and the refrigerant liquid can be supplied to
the discharge chamber 303 without increasing the pressure.
[0102] In the present embodiment, the refrigerant liquid is sprayed
into the discharge chamber 303 of the upper stage compressor 3b and
the lower stage compressor 3a from the branching path 51 and 54,
and the sprayed refrigerant liquid is evaporated in the discharge
chamber 303 with the potential heat of the discharge gas, and the
evaporative latent heat is taken from the discharge gas so as to
cool the discharge gas. Therefore, the heat transfer from the
discharge chamber 303 to the intake chamber 305 in the lower stage
compressor 3a and the upper stage compressor 3b is prevented.
[0103] As shown in FIG. 2 and FIG. 3, in the cylinder head 20 of
the lower stage compressor 3a and the upper stage compressor 3b,
the insulation gasket 39 is interposed between the valve plate 31
and the cylinder exterior body 23 so as to suppress the heat
transfer from the discharge chamber to the intake chamber by the
insulation gasket 39.
[0104] As shown in FIG. 4, the temperature of the intake chamber
305 of the lower stage compressor 3a is suppressed to -25.degree.
C. and the temperature of the intake chamber 305 of the upper stage
compressor 3b is suppressed to 15.degree. C. so as to prevent the
decline of the volumetric efficiency of the reciprocating
compressor and further maintain the performance of the
refrigeration unit 1.
[0105] The pressure in the discharge chamber 303 of the upper stage
compressor 3b and that of the branching path 51 are the same and
thus when supplying the refrigerant liquid to the discharge chamber
303 of the upper stage compressor 3b from the branching path 51, it
does not require the pressure regulating valve 53 to increase the
pressure of the refrigerant liquid by the liquid pump 52 and the
pressure regulating valve 53. On the other hand, the discharge
chamber 303 of the lower stage compressor 3a has low pressure and
thus when supplying the refrigerant liquid from the branching path
54 to the discharge chamber 303 of the lower stage compressor 3a,
it does not need pressure intensifying. Therefore, the pressure
booster is not needed and it requires less power.
[0106] The temperature of the intake gas of the lower stage
compressor 3a is lower than that of the intake gas of the upper
stage compressor. For instance, the temperature of the intake gas
of the lower stage compressor 3a is -30.degree. C. and the
temperature difference of the lower stage compressor is large
compared to that of the upper stage compressor. Therefore, the
temperature rise of the intake gas due to the heat transfer from
the discharge gas affects the lower stage compressor 3a more than
the upper stage compressor 3b. And by supply the refrigerant liquid
to the discharge chamber 303 of the lower stage compressor 3a to
the branching path 54, the temperature suppressing effect of the
intake gas is enhanced and the decline of the cooling capability is
avoided.
Third Embodiment
[0107] Next, a third embodiment of the present invention (Case 1 of
a single stage expansion and the two stage reciprocating
compressors 3a, 3b with an intercooler. The intercooler 61 feeds
the refrigerant liquid in the side of the liquid receiver 6 to the
expansion valve 7 and the evaporation unit 8 via a heat-transfer
pipe 61 and the refrigerant liquid is not decompressed in the
intercooler 61) is explained in reference to FIG. 5. In FIG. 5, a
heat exchanger 61 for liquid gas is provided in the refrigerant
circulating path 2a in the downstream side of the liquid receiver
6, and to the heat exchanger, connected is the refrigerant
circulating path 2b of the downstream side of the oil separator 4a.
And heat exchange take place in the heat exchanger 61 between the
refrigerant liquid from the liquid receiver 6 and the discharged
refrigerant gas in the downstream side of the oil separator 4a, and
the refrigerant liquid is cooled by the discharge refrigerant
gas.
[0108] The refrigerant liquid from the liquid receiver 6 passes
through the refrigerant circulating path 2a and reaches the
expansion valve 7. The refrigerant liquid is decompressed by the
expansion valve 7, the decompressed refrigerant liquid evaporating
in the evaporation unit 8 by taking the evaporative latent heat
from, and the evaporated refrigerant gas being introduced to the
intake chamber 305 of the lower stage compressor 3a. The
refrigerant gas being introduced to the intake chamber 305 is then
introduced to the cylinder 301 via the intake chamber 304 and
compressed in the cylinder 301. The rest of the configuration is
the same as that of the second embodiment shown in FIG. 4 and the
same devices or units have the same reference numbers as the second
embodiment, which will not be further explained herein.
[0109] The refrigerant liquid of the downstream side of the liquid
receiver is supplied to the discharge chamber 303 of the lower
stage compressor 3a via the branching path 54, and as shown in FIG.
2, is sprayed into the discharge chamber 303 via the injection
nozzle 306. Next, the refrigerant liquid is evaporated so as to
lower the temperature of the discharge gas inside the discharge
chamber 303. For instance, if the condensation temperature is
35.degree. C. and the evaporation temperature is -30.degree. C.,
the temperature of the refrigerant liquid in the condenser 5 and
the liquid receiver 6 is 35.degree. C. and the refrigerant liquid
is evaporated in the discharge chamber 303 and the evaporative
latent heat is absorbed so as to lower the temperature of the
discharge gas in the discharge chamber 303 to 10.degree. C.
[0110] The discharge gas having been cooled to 10.degree. C. is
introduced to the heat exchanger 61 in which the refrigerant liquid
having the temperature 35.degree. C. from the liquid receiver 6 is
cooled to 30.degree. C. in the heat exchanger 61.
[0111] In this manner, with the present embodiment, the similar
function effect to the second embodiment is obtained and by cooling
the refrigerant liquid at the exit side of the liquid receiver 6 by
the discharge gas of the lower stage compressor 3a in the heat
exchanger 61, the refrigeration capability of the refrigeration
unit 1 is further enhanced and COP can be improved.
[0112] In the upper stage compressor 3b, the head cover (discharge
chamber 303) may be cooled by water instead of injection of the
refrigerant liquid (injection nozzle 306), or maybe cooled by air
depending on the temperature conditions.
Fourth Embodiment
[0113] Next, a fourth embodiment of the present invention (Case 2
of single stage expansion and the two stage reciprocating
compressors 3a, 3b with an intercooler 61 which has the
configuration similar to the third embodiment) is explained in
reference to FIG. 6. In FIG. 6, the branching path 71 branches off
from a refrigerant exit pipe path 70 in the downstream side of the
heat exchanger 61 and is connected to the discharge chamber 303 of
the lower stage compressor 3a. The rest of the configuration is
similar to the third embodiment and thus the same devices and units
will not be explained further.
[0114] The terminal of the branching path 71 is connected to the
injection nozzle 306 provided in the discharge chamber of the lower
stage compressor 3a and the configuration of the discharge chamber
303 is the same as the first, second and third embodiments.
[0115] According to the present embodiment, in addition to the
cooling effect of the discharge gas in the discharge chamber 303 of
the lower stage and upper stage compressors 3a and 3b, the
refrigerant liquid having been over-cooled (30.degree. C.) by the
heat exchanger 61 is supplied to the discharge chamber 303 of the
lower stage compressor 32a via the branching path 71, thereby
further improving the cooling effect of the discharge gas of the
discharge chamber 303. Therefore, the supply of the refrigerant
liquid to the branching path 71 can be reduced, thereby downsizing
the injection nozzle 306.
[0116] Moreover, in the present embodiment, in the upper stage
compressor 3b, the head cover (discharge chamber 303) may be cooled
by water instead of injection of the refrigerant liquid (injection
nozzle 306), or maybe cooled by air depending on the temperature
conditions as suggested in the above-described embodiments.
Fifth Embodiment
[0117] Next, a fifth embodiment of the present invention (Case 3 of
using single stage expansion and the two stage reciprocating
compressors 3a, 3b with an intercooler 61 which forcibly cool
inside of the intercooler 81 by injecting the refrigerant liquid by
the expansion valve 83) is explained in reference to FIG. 7. The
present embodiment replaces the heat exchanger 61 of the fourth
embodiment shown in FIG. 4 with the intercooler 81 and the rest of
the configuration other than the intercooler 81 and the surrounding
components thereof is the same as the fourth embodiment. The
intercooler 81 has a branching path 82 branching from the
refrigerant circulating path 2a in the upstream side of the
intercooler 81 and the expansion valve 83 is provided in the
branching path 82.
[0118] The intercooler 81 of the present embodiment has a
heat-transfer pipe path 81a in communication with the refrigerant
circulating path therein and a space in which the discharge
refrigerant gas of the lower stage compressor 3a is filled is
provided outside of the pipe path 81 a and the heat exchange takes
place between the refrigerant liquid moving through the pipe path
81a and the discharge refrigerant gas through the pipe wall of the
pipe path 81a.
[0119] Moreover, the refrigerant liquid been heat-transferred in
the pipe path 81a of the intercooler 81 is introduced to the
expansion valve via the exit side pipe path 70.
[0120] Furthermore, the branching path 71 branches off from the
refrigerant exit pipe path 70 in the downstream side of the heat
exchanger 61 and is in communication with the discharge chamber of
the lower stage compressor 3a.
[0121] With the configuration above, the refrigerant liquid being
introduced to the branching path 82 passes through the expansion
valve 83 so as to be decompressed and then introduced to the
intercooler 81. The refrigerant liquid evaporates in the
intercooler absorbing the evaporative latent heat, thereby
improving the cooling effect of the refrigerant liquid introduced
to the pipe path 81a of the intercooler 81 from the refrigerant
circulating path 2a. The refrigerant liquid is cooled in the
intercooler 81, for instance to 25.degree. C.
[0122] Consequently, with the present embodiment in comparison with
the fourth embodiment, the cooling effect of the refrigerant liquid
by the intercooler 81 is improved, thereby further reducing the
temperature of the refrigerant liquid at the exit side of the
intercooler 81. Thus, the temperature of the refrigerant being
supplied to the discharge chamber 303 of the lower stage compressor
3a from the branching path 71 can be further reduced, thereby
further improving the temperature regulating effect of the
discharge gas of the lower stage compressor 3a. Furthermore, the
cooling effect of the refrigerant liquid being introduced to the
expansion valve is improved, further enhancing the cooling
capability of the refrigeration unit 1.
Sixth Embodiment
[0123] Next, a sixth embodiment of the present invention (Case of
using the two stage reciprocating compressors and a two-stage
expansion with an intercooler 91. The two-stage expansion is
performed such that the refrigerant liquid from the liquid receiver
6 is injected from the expansion valve 92 to an expansion space 91a
inside the intercooler 91 and the refrigerant liquid received in
the bottom of the space is introduced to the evaporation unit 8 via
the expansion valve 7.) is explained in reference to FIG. 8. The
present embodiment replaces the heat exchanger 61 of the third
embodiment with the intercooler 91. And the expansion valve 92 is
provided in the refrigerant circulating path 2a in the upstream
side of the intercooler 91. The rest of the configuration is the
same as the third embodiment.
[0124] With this configuration, the refrigerant liquid of the
refrigerant circulating path 2a passes through the expansion valve
92 so as to be decompressed and then introduced to the intercooler
91. The refrigerant liquid evaporates in the intercooler absorbing
the evaporative latent heat of the discharge gas of the lower stage
compressor 3a inside the intercooler. The intercooler 91 of the
present embodiment is formed like a closed vessel with a hollow
space inside and contact heat exchange takes place between the
refrigerant liquid and the discharge gas inside the hollow
space.
[0125] According to the present embodiment in comparison with the
third embodiment, by providing the intercooler 91 instead of the
heat exchanger 61, the cooling effect of the refrigerant liquid
reaching the expansion valve is further enhanced (e.g. cooling to
1.degree. C.) and the cooling effect of the refrigerant gas being
supplied to the discharge chamber 305 of the upper stage compressor
3b is enhanced as well (e.g. cooling to 6.degree. C.).
[0126] Furthermore, in comparison with the fifth embodiment shown
in FIG. 7, it does not require the heat transfer pipe arranged in
the intercooler 91, thereby reducing equipment cost.
Seventh Embodiment
[0127] Next, a seventh embodiment of the present invention is
explained in reference to FIG. 9. FIG. 9 illustrates an elevation
plan of a cylinder top assembly 100 of the reciprocating compressor
to be integrated in the refrigeration unit of the present
invention. The reciprocating compressor of the present embodiment
comprises a pair of cylinders.
[0128] As illustrated in FIG. 9, a piston 102 is slidably
positioned in the cylinder 101. The cylinder 101 is placed on an
exterior body 103. On top of the cylinder exterior body 103, a
valve plate 111 is positioned which has openings 111a. The openings
111a are concentrically positioned to correspond to the top opening
of the cylinders 101. The valve plate 111 has cavities in which the
plate-type intake valve 105 forming a ring shape and a volute
spring 106 on top of the intake valve are housed.
[0129] An elastic force of the volute spring 1066 works on the
intake valve 105 so as to press the intake valve 105 against a top
of the cylinder 101. An intake chamber 104 and an intake gas
passageway 104a in communication with the intake chamber 104 are
arranged under the intake valve 105. When the piston 102 moves
downward in the cylinder 101, the pressure in the cylinder 101
becomes small, causing the pressure difference between the cylinder
101 and the intake chamber 104. During the step, the refrigerant
gas g.sub.1, lifts the intake valve 105 and is introduced into the
cylinder.
[0130] A valve cage 112 in a shape of circular plate is provided
above the valve plate 111 so as to close the opening 111a of the
valve plate 111. A valve plate 114 in a shape of a conical frustum
is joined to the bottom of the valve cage 112 with a bolt 113.
[0131] A discharge gas passageway 116a is formed in the valve cage
112 and a volute spring is equipped on the valve cage 112. Under
the volute spring 117, a plate-like discharge valve 118 in a shape
of a ring is provided beside the discharge gas passageway 116a.
[0132] When the piston rises and the pressure of the discharge gas
of the cylinder 101 becomes large, the discharge gas g.sub.2 pushes
up the discharge valve 118 and is discharged to the discharge gas
passageway 116a.
[0133] Above the valve cage 112, a head cover 121 is arranged so as
to form a discharge chamber 116 on top of the valve cage 112. The
discharge chamber 116 is in communication with the discharge gas
passageway 116a and also feeds the high-pressure discharge gas
being discharged from the cylinder 101 to the refrigerant
circulating path.
[0134] The refrigerant gas g2 being discharged from the discharge
gas passageway 116a to the discharge chamber 116 passes through a
passageway 107 formed in the cylinder exterior body 103 and is fed
to the refrigerant circulating path. The passageway 107 is arranged
adjacent to the intake chamber 104 and the intake gas passageway
104a via a wall of a partition wall of the exterior body 103.
[0135] As illustrated in FIG. 9, both of the head cover 121 and the
cylinder exterior body 103 have through-bores 121a and 121b
respectively which are connected to the branching pipe paths 122a
and 122b respectively which correspond to the branching pipe path 9
of FIG. 1. The through-bore 121a opens to the inner wall of the
head cover and the through-bore 121b opens to the passageway 107.
And the injection nozzles 123a and 123b are installed in the
openings of the through-bores 121a and 121b respectively. By this,
the condensed refrigerant liquid from the liquid receiver not shown
in the drawing is sprayed to the discharge chamber 116 and the
passageway 107 via the branching pipe paths 122a and 122b.
[0136] On the surface of the head cover 121, a cooling water
filling space 125 is hermetically formed such that a cooling water
jacket 124 covers the head cover. A cooling water supply hole 124a
is provided in the cooling water jacket 124 so as to fill the space
125 with the cooling water w from the hole 124a.
[0137] In the present embodiment, the refrigerant liquid is sprayed
to the discharge chamber 116 and the passageway 107 in a form of
fine particles through the injection nozzle 123a and 123b so as to
improve the absorption effect of the evaporative latent heat of the
discharge gas.
[0138] The passageway 107 is arranged adjacent to the intake
chamber 104 and the intake gas passageway 104a via a wall of a
partition wall of the exterior body 103. But the heating of the
discharge gas passing through the intake chamber 104 and the intake
gas passageway 104a is prevented by spraying the refrigerant liquid
to the passageway 107 through the injection nozzle 123b and
suppressing the temperature rise of the discharge gas.
Eighth Embodiment
[0139] An eighth embodiment of the present invention is explained
in reference to FIG. 10. In the present embodiment shown in FIG.
10, in comparison with the first embodiment shown in FIG. 1 to FIG.
3, the branching path 9 branching the refrigerant liquid in the
downstream side of the liquid receiver 6 is omitted in the
refrigeration unit 1 and the branching pipe path 9 is not connected
inside the discharge chamber 303 of the single stage reciprocating
compressor 3, and the injection nozzle is not installed. The rest
of the configuration is the same as the first embodiment of the
present invention.
[0140] In the present embodiment, the cooling of the discharge gas
in the discharge chamber 36 by using the evaporative latent heat of
the condensed refrigerant liquid is not conducted.
[0141] And the heat transfer between the intake chamber 36 and
discharge chamber 24 is prevented by installing the insulation
gasket 39 between the valve plate 31 and the cylinder exterior body
2, thereby suppressing the temperature rise of the intake gas in
the intake chamber 24. Moreover as shown in FIG. 3, the insulation
space i is formed between the cylinder exterior body and the gasket
in an area interposed by the cylinders, thereby enhancing the
insulation effect.
[0142] By this, the temperature rise of the intake gas before
reaching the cylinder is suppressed, thereby avoiding the decline
in the volumetric efficiency of the reciprocating compressor and
maintaining the refrigerating capability of the refrigeration unit
1.
Ninth Embodiment
[0143] Next, a ninth embodiment of the present invention (in the
case of using single stage expansion and the two stage
reciprocating compressors 3a, 3b with an intercooler 81. The
intercooler 81 is forcibly cooled inside by injecting the
refrigerant liquid by the expansion valve 83 and the refrigerant at
room temperature of the liquid receiver 6 is supplied to the
discharge chamber 303) is explained in reference to FIG. 12. The
present embodiment shares the same configuration with the fifth
embodiment besides the intercooler 81 and the surrounding
components. The refrigerant circulating path 2a comprises a pathway
2a arranged through the intercooler 81 and another pathways 2b and
71a branching from the pathway 2a to bypass the intercooler. The
refrigerant at room temperature of the liquid receiver is fed to
the nozzle 306 of the discharge chamber of the lower stage
compressor 3a.
[0144] With the configuration as described above, preferable
effects described below can be obtained in comparison with the case
of supplying the low temperature refrigerant having passed through
the intercooler 81 to the discharge chamber 303 of the lower stage
compressor 3a.
[0145] The intercooler 81 and the heat-transfer pipe path 81a (for
low temperature liquid) are insulated so as to avoid the heating
from the external air (or the temperature of the surrounding
devices).
[0146] Especially, when the heat penetrates from outside through
the valve or the like to the pipe or heat exchanger which is full
of liquid, it is prone to the heat expansion and thus causing
explosion from where it is weak. However, in the present embodiment
the pathway 2a arranged through the intercooler and another
pathways 2b and 71a branching from the pathway 2a to bypass the
intercooler 81 are provided in such a manner that the refrigerant
at room temperature of the liquid receiver 6 is directly led to the
discharge chamber 303 of the low stage compressor 3a, thereby
solving the above problem.
INDUSTRIAL APPLICABILITY
[0147] According to the present invention, the temperature rise of
the intake refrigerant gas inside the reciprocating compressor is
suppressed and the refrigerant gas of high density can be
introduced, thereby improving the volumetric efficiency and further
enhancing the performance of the heat pump unit such as a
refrigeration unit having the reciprocating compressor integrated
therein. Therefore, the highly efficient heat pump unit and
refrigeration unit of the reciprocating unit in which the
temperature rise of the intake gas in the compressor is suppressed
and at the same time cooling water is not used, can be
obtained.
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