U.S. patent application number 09/730766 was filed with the patent office on 2001-06-14 for temperature control device for thermal medium fluid.
Invention is credited to Ryu, Hideo, Sakamoto, Yasushi, Shimoda, Kazuyoshi, Sugiyama, Motoharu, Takikawa, Kazunori, Watanabe, Ikuo.
Application Number | 20010003347 09/730766 |
Document ID | / |
Family ID | 26578783 |
Filed Date | 2001-06-14 |
United States Patent
Application |
20010003347 |
Kind Code |
A1 |
Shimoda, Kazuyoshi ; et
al. |
June 14, 2001 |
Temperature control device for thermal medium Fluid
Abstract
A temperature control device for a constant temperature chiller
unit or a vending machine is provided. Thermal medium fluid such as
water in the chiller unit is accurately controlled under starting
mode, heating mode and cooling mode. Thermal medium fluid such as
air in the vending machine is conveniently controlled in winter
mode and summer mode. In the device, a heat exchanger is interposed
within a compression circuit, and a bypass circuit is disposed at
the downstream side of a pump so that through the bypass circuit
thermal medium fluid receives heat from the heat exchanger. Thus,
the temperature of thermal medium fluid supplied to an external
secondary heat load is controlled,
Inventors: |
Shimoda, Kazuyoshi; (Tokyo,
JP) ; Sakamoto, Yasushi; (Shizuoka, JP) ; Ryu,
Hideo; (Shizuoka, JP) ; Sugiyama, Motoharu;
(Numazu, JP) ; Watanabe, Ikuo; (Susono, JP)
; Takikawa, Kazunori; (Numazu, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
Suite 800
2033 K Street, N.W.
Washington
DC
20006
US
|
Family ID: |
26578783 |
Appl. No.: |
09/730766 |
Filed: |
December 7, 2000 |
Current U.S.
Class: |
236/13 |
Current CPC
Class: |
F25D 17/02 20130101;
F25B 29/003 20130101; G05D 23/1919 20130101; F25B 2400/24
20130101 |
Class at
Publication: |
236/13 |
International
Class: |
G05D 023/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 8, 1999 |
JP |
11-348595 |
Aug 17, 2000 |
JP |
2000-247385 |
Claims
1. In a temperature control device for thermal medium fluid
comprising a constant temperature tank for thermal medium fluid, a
refrigerating circuit having a compressor, a condenser and an
evaporator, and a thermal medium fluid circulation circuit for
circulating constant temperature thermal medium fluid through the
tank toward an external secondary heat load by a pump,
characterized in that; (a) a heat exchanger is interposed within a
compression circuit between said compressor and said condenser, so
that said compression circuit becomes a primary circuit of the heat
exchanger, (b) a bypass circuit is disposed at the downstream side
of said pump, so that through the bypass circuit thermal medium
fluid passes through the secondary circuit of said heat exchanger
toward said circulation circuit, (c) fluid flow in said bypass
circuit is controlled by a flow control valve, and heated thermal
medium fluid by said heat exchanger is introduced into said
circulation circuit, whereby the temperature of thermal medium
fluid supplied to said secondary heat load is controlled.
2. A temperature control device of claim 1, wherein said evaporator
is comprised of multi-tube type cylindrical evaporator and this
cylindrical evaporator works as said constant temperature tank.
3. In a temperature control device for thermal medium fluid
comprising a refrigerating circuit having a compressor, a condenser
and an evaporator, a cooling circuit for the condenser, and a
thermal medium fluid circulation circuit for circulating thermal
medium fluid toward an external secondary heat load by a pump,
characterized in that; (a) a heat exchanger is interposed within a
compression circuit between said compressor and said condenser, so
that said compression circuit becomes a primary circuit of the heat
exchanger, (b) a first bypass circuit is disposed at the downstream
side of said pump, so that through the first bypass circuit thermal
medium fluid passes through the secondary circuit of said heat
exchanger toward said circulation circuit, (c) fluid flow in said
bypass circuit is controlled by a flow control valve, and heated
thermal medium fluid by said heat exchanger is introduced into said
circulation circuit, whereby the temperature of thermal medium
fluid supplied to said secondary heat load is controlled, (d) a
second bypass circuit is interposed between the downstream side of
said condenser and the downstream side of said evaporator, and a
capillary tube and an electromagnetic valve is disposed within the
second bypass circuit, (e) fluid flow in said second bypass circuit
is controlled by said electromagnetic valve, whereby the cooling
temperature cooled by said evaporator is controlled and an overheat
of said compressor is prevented.
4. A temperature control device of claim 3, wherein an
electromagnetic valve with a throttle valve is disposed within said
cooling circuit for the condenser, whereby the temperature of said
condenser is controlled.
5. In a temperature control device for an automatic vending machine
which stores articles therein and can change itself into a cooling
mode and heating mode in relation to the season or other
conditions, characterized in that; (a) the device comprises at
least one article storing compartment, and a refrigerating circuit
having a compressor, a condenser and an evaporator, (b) a first
electromagnetic valve is disposed at the inlet side of said
evaporator, (c) a second electromagnetic valve is disposed at an
intermediate point between the outlet side of said compressor and
the inlet side of said condenser, (d) a bypass circuit with a third
electromagnetic valve is interposed between the outlet side of said
compressor and the inlet side of said condenser so that this bypass
circuit can bypass said second electromagnetic valve, (e) a heat
exchanger is disposed within said bypass circuit, (f) said
evaporator and said heat exchanger are disposed within said article
storing compartment, whereby it is possible to select itself a heat
absorbing mode by said evaporator or heat emitting mode by said
heat exchanger through the exchange operation of said first, second
and third electromagnetic valves.
6. A temperature control device of claim 5, wherein a second bypass
circuit is interposed between the downstream side of said condenser
and the downstream side of said evaporator, and a capillary tube
and a fourth electromagnetic valve are disposed within the second
bypass circuit, and fluid flow in said second bypass circuit is
controlled by said fourth electromagnetic valve, whereby the
cooling temperature cooled by said evaporator is controlled.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to a temperature control device for a
constant temperature chiller unit which provides thermal medium
fluid such as cold water of constant temperature toward a
semiconductor manufacturing device, a laser machine, or
miscellaneous scientific or chemical instruments in a fluid
circulating mode, and to a temperature control device for an
automatic vending machine which stores articles therein and can
change itself into a cooling mode and heating mode in relation to
the season or other conditions.
[0002] In the prior constant temperature chiller unit, thermal
medium fluid such as pure water or "fluorinert" (supplied by 3M
corporation) is supplied through a refrigerating systemcomprised of
a compressor, a condenser and an evaporator for fron gas (Freon
gas). In this process, high temperature fron gas compressed by a
compressor is liquidized by a condenser into liquid fron, and the
liquid fron absorbs heat from the surroundings when it is
evaporated by an evaporator, whereby produces temperature medium
fluid such as low temperature pure water or "fluorinert".
[0003] When the range of the allowable temperature is limited in a
small range, such as in a semiconductor manufacturing device which
requires an accurate setting of plus and minus 1.degree. C., if the
refrigerator (evaporator) is operated at a maximum power for
cooling, the temperature of the thermal medium fluid goes down too
low, thereby being overcooled. For compensating this problem, a
constant temperature tank having a buffer capacity of three to five
times of cold water flow per minute is disposed, and the tank is
provided with an electrical heater for controlling the temperature.
Then, extra electrical power is necessary, whereby the overall size
of the apparatus becomes large and additional cost for setting and
operation becomes necessary.
[0004] Referring to FIG. 8, there is shown a constant temperature
tank with a heater of prior art. The constant temperature tank 16
produces cold water by a refrigerating circuit 1 comprised of a
compressor 12, a condenser 14 and an evaporator 20. The produced
cold water is supplied to the external secondary heat load 24 such
as a semiconductor manufacturing device by the pump 22, and is
circulated within the cold water circulating circuit 3. In the
refrigerating circuit 1, there is provided a dryer 15, and in the
cold water circulating circuit 3, there are provided a pressure
controller 17, a relief valve 19 and pressure gauge G. Within the
constant temperature tank 16, there are provided a sensor for
detecting overheat and freezing, and a sensor for detecting water
level of the tank. Each sensor is connected to an overheat and
freezing monitor (arrow A) and to a water level monitor (arrow B),
respectively. To the bottom of the tank 16, a drain circuit 28 is
connected and a drain valve 19 is disposed for controlling the
drain port (arrow C).
[0005] Thus, high temperature fron gas (refrigerant) compressed by
a compressor 12 in the refrigerating system is liquidized by a
condenser 14 into liquid fron, and the liquid fron absorbs heat
from the surroundings when it is evaporated by the evaporator 20,
whereby produces cold water. On the other hand, the condenser 14 is
exposed to high temperature. For cooling the condenser 14, a
cooling circuit 2 comprised of water cooling type cooler 26 is
provided. The cooler 26 is cooled by any of cooling tower water,
factory circulating water or underground water. In this circuit 2,
cooling water is circulated by operating a flow swith 25 and a
control valve 27, so that the condenser 14 is cooled.
[0006] However, when the range of the allowable temperature is
limited in a small range, such as in a semiconductor manufacturing
device, if the evaporator 20 (refrigerator) is operated at a
maximum power for cooling, the temperature of the thermal medium
fluid goes down too low, thereby being overcooled. For compensating
this problem, an electrical heater 50 is attached to the constant
temperature tank 16 for controlling its temperature. The heater 50
is also used for raising the temperature of thermal medium fluid
during its starting mode. As a result, extra electrical power is
required, whereby there needs an additional cost.
[0007] In other methods for controlling the temperature, hot gas
bypass method or refrigerator ON and OFF method are known. However,
in the former method, cooling and heating should be alternately
exchanged, whereby the response of temperature control is poor and
the bypass valve is not reliable so that it often fails. In the
latter method, a large capacity buffer tank should be disposed, so
that the overall size becomes larger and the accuracy of the
temperature control becomes poor.
[0008] In an automatic vending machine which can change itself into
a cooling mode and heating mode in relation to the season, a
powerful heater is inevitable. Accordingly, extra electrical power
is required and there needs an additional cost.
[0009] Japanese unexamined patent publication No. Hei 9-72644
entitled "Cold water circulation supply machine for scientific and
chemical machines" and Japanese unexamined patent publication No.
Hei 9-196512 entitled "Cooling liquid supply device" relate to a
constant temperature chiller unit as a cold water supply
device.
SUMMARY OF THE INVENTION
[0010] It is a first object of the present invention to provide a
temperature control device for thermal medium fluid in which an
electrical heater is eliminated from the constant temperature tank
thereby reducing the electrical power so that it can improve the
accuracy and response of the device.
[0011] It is a second object of the present invention to provide a
temperature control device for thermal medium fluid in which the
constant temperature tank is eliminated thereby reducing the
overall size of the device.
[0012] It is a third object of the present invention to provide a
temperature control device for thermal medium fluid in which the
working range is extended from -40.degree. C. to 60.degree. C.
relative to the prior art.
[0013] It is a fourth object of the present invention to provide a
temperature control device for thermal medium fluid in which the
electrical power in a starting mode is considerably reduced.
[0014] It is a fifth object of the present invention to provide a
power saving type temperature control device for an automatic
vending machine which stores articles therein and can change itself
into a cooling mode and heating mode in relation to the season or
other conditions.
[0015] A first object of the present invention is achieved by the
device in which a heat exchanger is interposed within a compression
circuit between a compressor and a condenser so that the
compression circuit becomes a primary circuit of the heat
exchanger, and a bypass circuit is disposed at the downstream side
of a pump. Through the bypass circuit, thermal medium fluid passes
through a secondary circuit of the heat exchanger toward a
circulation circuit, and fluid flow in the bypass circuit is
controlled by a flow control valve. Heated thermal medium fluid by
the heat exchanger is introduced into the circulation circuit.
Thus, the temperature of thermal medium fluid supplied to an
external secondary heat load is controlled.
[0016] Based upon above characteristics of the first embodiment of
the invention, a part of the heat of the high temperature fron gas
compressed by the compressor is given to the thermal medium fluid
(water) which is supplied to the external secondary heat load so
that the temperature of the overcooled thermal medium fluid (cold
water) cooled by the regrigerating circuit is raised and controlled
within a predetermined temperature range. Thus, the accuracy and
response of the device are improved. Since the electrical heater in
the prior art is eliminated, the electrical power and cost are
reduced.
[0017] The second object of the present invention is achieved by
the device in which the evaporator is comprised of multi-tube type
cylindrical evaporator and this cylindrical evaporator works as the
constant temperature tank. The capacity of the cylindrical
evaporator is preferably 0.1 to 2.0 times of cold water flow per
minute, more preferably 0.25 to 1.5, further prefferably 0.5 to
1.0. Thus, according to the invention, it becoms possible to
eliminate the constant temperature tank so that the overall size of
the device is reduced.
[0018] The third object of the present invention is achieved by a
similar device as the first aspect of the invention. In addition to
the first aspect, a cooling circuit of the condenser is disposed.
Further, a second bypass circuit is interposed between the
downstream side of the condenser and the downstream side of the
evaporator, and a capillary tube and an electromagnetic valve are
disposed within the second bypass circuit. Fluid flow in the second
bypass circuit is controlled by the electromagnetic valve, whereby
the cooling temperature cooled by the evaporator is controlled and
an overheat of the compressor is prevented. In this aspect, since
the cooling temperature of the evaporator can be controlled by the
second bypass, the working temperature range is considerably
extended relative to the prior art.
[0019] The fourth object of the present invention is achieved by a
modification of the above aspect. In the modification, an
electromagnetic valve with a throttle valve is disposed within the
cooling circuit for the condenser, whereby the temperature of the
condenser is controlled. Thus, the controllable temperature range
of the device is extended. Especially, at the starting mode, by
stopping the cooling of the condenser, it becomes possible to
rapidly raise the temperature of the device toward a predetermined
value.
[0020] The fifth object of the present invention is achieved by a
temperature control device for an automatic vending machine which
stores articles therein and can change itself into a cooling mode
and heating mode in relation to the season or other conditions.
According to the characteristics of the device, it comprises at
least one article storing compartment, and a refrigerating circuit
having a compressor, condenser and an evaporator. A first
electromagnetic valve is disposed at the inlet side of the
evaporator, and a second electromagnetic valve is disposed at an
intermediate point between the outlet side of the compressor and
the inlet side of the condenser. A bypass circuit with a third
electromagnetic valve is interposed between the outlet side of the
compressor and the inlet side of the condenser so that this bypass
circuit can bypass the second electromagnetic valve. A heat
exchanger is disposed within the bypass circuit, and the evaporator
and the heat exchanger are disposed within the article storing
compartment. Thus, it is possible to select itself a heat absorbing
mode by the evaporator or heat emitting mode by the heat exchanger
through the exchange operation of the first, second and third
electromagnetic valves.
[0021] Based upon the above characterics, according to the
automatic vending machine of the invention, a conventional powerful
electric heater for heating the articles is saved and a small
heater may be substituted for the powerful heater. Thus, electric
power and cost are considerably saved.
[0022] As a preferable modification of the above characteristics, a
second bypass circuit is interposed between the downstream side of
the condenser and the downstream side of the evaporator, and a
capillary tube and a fourth electromagnetic valve are disposed
within the second bypass circuit. Fluid flow in the second bypass
circuit is controlled by the fourth electromagnetic valve so that
the cooling temperature cooled by the evaporator is controlled.
Thus the temperature control range is considerably extended.
[0023] Other characteristics and advantages of the present
invention will be apparent from a reading of the following
specification referring to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a schematic diagram of the temperature control
device according to the first embodiment of the invention.
[0025] FIG. 2 is a schematic diagram of the temperature control
device according to the second embodiment of the invention.
[0026] FIG. 3 is a schematic diagram of the temperature control
device in its starting mode according to the third embodiment of
the invention.
[0027] FIG. 4 is a schematic diagram of the device of FIG. 3 in its
heating mode.
[0028] FIG. 5 is a schematic diagram of the device of FIG. 3 in its
cooling mode.
[0029] FIG. 6 is a schematic diagram of the temperature control
device in its winter mode according to the fourth embodiment of the
invention.
[0030] FIG. 7 is a schematic diagram of the device of FIG. 6 in its
summer mode.
[0031] FIG. 8 is a schematic diagram of the temperature control
device according to the prior art.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0032] Referring to FIG. 1, there is shown a temperature control
device for thermal medium fluid of a first embodiment of the
present invention. This device comprises a refrigerating circuit 1,
a cooling circuit 2 for a condenser 14, and a thermal medium fluid
circulation circuit 3 for circulating thermal medium fluid toward
an external secondary heat load 24 by a pump 22. The circuit 1
includes a compressor 12, a condenser 14, a PI (proportional
integral) control expansion valve 36, and an evaporator 20. A
constant temperature tank 16 produces cold water (thermal medium
fluid) by the refrigerating circuit 1, and the produced cold water
is supplied to the external secondary heat load 24 such as a
semiconductor manufacturing device by the cold water supply pump
22. The condenser 14 is provided with a water cooling type cooler
26 which can be cooled by cooling tower water, factory circulation
water or underground water, so that the condenser 14 is cooled by a
cold water circulation operated by a flow switch 25 and a water
flow comtrol valve 27.
[0033] Based upon the charasterics of the invention, a heat
exchanger 30, preferably made by a multi-tube type having a
property of small flow resistance, is interposed within a
compression circuit between the compressor 12 and the condenser 14
so that the compression circuit 31 becomes a primary circuit of the
heat exchanger 30. The PI control type expansion valve 36 and a
dryer 15 are disposed within a condensed circuit from the condenser
14 to the evaporator 20. At the downstream side of the cold water
supply pump 22, a bypass circuit 40 is disposed so that through the
bypass circuit thermal medium fluid passes through the secondary
circuit 32 of the heat exchanger 30 toward the circulation circuit
3.
[0034] Thus, a part of the cold water supplied from the cold water
supply pump 22 to the secondary heat load 24 is delivered to the
bypass 40 by an operation of an electrically driven flow control
valve 38, whereby cold water heated by the heat exchanger 30 is
returned to the cold water circulation circuit 3 toward the
downstream side of the cold water supply pump 22. By electrically
controlling the fluid flow passing through the flow control valve
38, the quantity of heated water mixed to the cold water supplied
to the external secondary heat load 24 can be controlled. Thus,
temperature control of the cold water is effected.
[0035] In addition, a cut off valve 41 is disposed within the
circulation circuit 3, so that together with the operation of the
flow control valve 38 all of the cold water flow directed toward
the external secondary heat load 24 can be introduced into the
bypass 30.
[0036] As a result of an experiment using this temperature control
device, an electrical power consumption is reduced to fifty percent
relative to the prior chiller unit, so that the temperature control
performance is greatly improved. Further, since the electrical
heater is eliminated, the size of the chiller unit is reduced and
quantity of circulation water is relatively saved.
[0037] Referring to FIG. 2, there is shown a temperature control
device for thermal medium fluid of a second embodiment of the
present invention. In this embodiment, the evaporator is comprised
of a multi-tube type cylindrical evaporator 46 having a great
capacity of cold water, and this cylindrical evaporator 46 works
the same as the constant temperature tank 16 in FIG. 1. The
capacity of the cylindrical evaporator 46 is preferably 0.1 to 2.0
times of cold water flow per minute, more preferably 0.25 to 1.5,
further prefferably 0.5 to 1.0. Thus, according to the second
embodiment of the invention, it becomes possible to eliminate the
constant temperature tank so that the overall size of the device is
reduced.
[0038] Referring to FIGS. 3 to 5, there is shown a temperature
control device for thermal medium fluid of a third embodiment of
the present invention. This device comprises a refrigerating
circuit 1, a cooling circuit 2 for a condenser 14, and a thermal
medium fluid circulation circuit 3 for circulating thermal medium
fluid toward an external secondary heat load 24 by a pump 22. The
circuit 1 includes a compressor 12, a condenser 14, a PI control
expansion valve 36, and an evaporator 20. The pump 22 is controlled
by an inverter 23.
[0039] FIG. 3 shows a starting mode from a low temperature range
between -40.degree. C. and -10.degree. C. to room temperature, FIG.
4 shows a heating mode from the room temperature to a high
temperature range between 50.degree. C. and 60.degree. C. and FIG.
5 shows a cooling mode in a standard working condition.
[0040] In this embodiment, cold water (thermal medium fluid) is
produced by the refrigerating circuit 1, and the produced cold
water is supplied to the external secondary heat load 24 such as a
semiconductor manufacturing device by the cold water supply pump
22. The condenser 14 is provided with a water cooling type cooler
26 which can be cooled by cooling tower water, factory circulation
water or underground water, so that the condenser 14 is cooled by a
cold water circulation operated by a flow switch 25 with a throttle
valve and a water flow comtrol valve 27. Within the thermal medium
fluid circulation circuit 3, a relief valve 19 and a buffer tank 21
with a level meter are disposed. Other gauges and sensors such as a
high pressure sensor 33, a low pressure sensor 35, temperature
sensors 44, 45, a pressure sensor 46, a flow meter 47, a water
temperature gauge 48, a room temperature gauge 49 are connected as
required. At the inlet side of the condenser 14, a storage tank 34
for fron gas is disposed in order to prevent the fron gas pressure
from going up extraordinarily.
[0041] Based upon the characterics of the invention, a heat
exchanger 30, preferably made by a mylti-tube type having a
property of small flow resistance, is interposed within a
compression circuit between the compressor 12 and the condenser 14
so that the compression circuit 31 becomes a primary circuit of the
heat exchanger 30. At the downstream side of the cold water supply
pump 22, a bypass circuit 40 and an electrically driven three way
flow control valve 41 are disposed so that through the bypass
circuit thermal medium fluid passes through the secondary circuit
32 of the heat exchanger 30 toward the circulation circuit 3.
[0042] Thus, a part of the cold water supplied from the cold water
supply pump 22 to the external secondary heat load 24 is delivered
to the bypass 40 by an operation of the electrically driven three
way flow control valve 41. The cold water heated by the heat
exchanger 30 is returned to the cold water circulation circuit 3
toward the downstream side of the cold water supply pump 22. By
electrically controlling the fluid flow passing through the flow
control valve 38 (PID control), the quantity of heated water mixed
to the cold water supplied to the external secondary heat load 24
can be controlled, so that temperature control of the cold water is
effected.
[0043] Based upon the further charasterics of the invention, a
second bypass circuit 42 is interposed between the downstream side
of thr condenser 14 and the downstream side of the evaporator 20,
and a capillary tube 43 and an electromagnetic valve 37 are
disposed within the second bypass circuit 42. Thus, the fluid flow
in the second bypass circuit 42 is controlled by an ON and OFF
operation of the electromagnetic valve 37, whereby the cooling
temperature cooled by the evaporator 20 is controlled and an
overheat of the compressor 12 is prevented.
[0044] In a starting mode during an opening operation in FIG. 3,
the electromagnetic valve 37 is opened (ON), the pump side of the
three way valve 41 is opened (ON), the electromagnetic valve 25 of
the cooler 26 is opened (ON), whereby heat absorbing performance of
the evaporator 20 is low. The heat exchanger 30 reaches high
temperature, and the condenser 14 also reaches high
temperature.
[0045] In this starting mode, when it is raised from the low range
between -40.degree. C. and -10.degree. C. to the level of room
temperature, the heat of the cooler 26 is introduced to the
condenser 14 in order to avoid a temporary suspension of the
compressor 12. This type of suspension is caused by an accident in
which the low pressure side of the refrigerating circuit becomes a
vacuum condition.
[0046] On the other hand, during the heating mode in FIG. 4 after
the opening operation, the electromagnetic valve 37 is opened (ON),
the pump side of the three way valve 41 is closed (OFF), the
electromagnetic valve 25 of the cooler 26 is closed (OFF), whereby
heat absorbing performance of the evaporator 20 is low. The heat
exchanger 30 is kept in high temperature, and the condenser 14 is
also kept in high temperature.
[0047] Thus, it becomes possible to use the compressor 12 as a
heater. During this mode, in order to avoid an overheat of the
compressor 12 and to protect the compressor 12, fron gas is
introduced into the bypass circuit 42 of the capillary tube 43.
[0048] During a cooling mode in FIG. 5 in a standard stable
condition, the electromagnetic valve 37 is closed (OFF), the pump
side of the three way valve 41 is opened (ON), the heat exchanger
side of the three way valve 41 is opened (ON), and the
electromagnetic valve 25 of the cooler 26 is opened (ON), whereby
heat absorbing performance of the evaporator 20 is high. The heat
exchanger 30 and the condenser 14 are kept in relatively low
temperature as compared with the starting mode and the heating
mode..
[0049] As a result of an experiment using this temperature control
device, an electrical power consumption is reduced to fifty percent
relative to the prior chiller unit, whereby the temperature control
performance is greatly improved. Further, since the electrical
heater is eliminated, the size of the chiller unit is reduced and
quantity of circulation water is relatively saved.
[0050] Referring to FIGS. 6 and 7, there is shown a temperature
control device for an automatic vending machine of a fourth
embodiment of the present invention. This device includes three
compartments consisting of a cooling compartment 61, and two
cooling and heating variable compartments 62, 63, each of them
containing articles such as soft drinks.
[0051] Within each compartment, one of evaporators 66, 67, 68 is
disposed so that inside air as thermal medium fluid is cooled by a
refrigerating circuit including a condenser 52 and an evaporator
54. FIG. 6 shows a winter mode in which the variable compartments
62, 63 are laid on heating mode corresponding to winter, and FIG. 7
shows a summer mode in which the variable compartments 62, 63 are
laid on cooling mode corresponding to summer.
[0052] Based upon the characteristics of the invention, at an inlet
side of each evaporator a first electromagnetic valve 73, 75 or 76
is disposed, and at an intermediate point between an outlet side of
the compressor 52 and an inlet side of the condenser 54 a second
electromagnetic valve 71 is disposed. Further, a first bypass
circuit 77 is interposed between the outlet side of the compressor
52 and the inlet side of the condenser 54 so that this bypass
circuit 77 can bypass the second electromagnetic valve 71. The
first bypass circuit 77 includes a third electromagnetic valve 72
and extends into the cooling and heating variable compartments 62,
63, and within each variable compartment one of heat exchangers 56,
58 is disposed.
[0053] Thus, through the exchange operation of the first, second
and third electromagnetic valves, it becomes possible to select
itself a heat absorbing mode (cooling) by the evaporators 67, 68
and heat emitting mode (heating) by the heat exchangers 56, 58.
[0054] According to further characteristics of the invention, a
second bypass circuit 79 is interposed between the downstream side
of the condenser 54 and the downstream side of the evaporators 67,
68, and a capillary tube 78 and a fourth electromagnetic valve 74
are disposed within the second bypass circuit 79. Thus, the fluid
flow in the second bypass circuit 79 is controlled by the fourth
electromagnetic valve 74, whereby the cooling temperature cooled by
the evaporators 67, 68 is controlled. In addition, an overheat of
the compressor 52 is prevented.
[0055] In operation in the winter mode as shown in FIG. 6, the
electromagnetic valves 71, 73, 75 are closed (OFF) thereby ceasing
the cooling work of the evaporators 67, 68, and the electromagnetic
valves 72, 74 are opened (ON) thereby raising the temperature of
the heat exchangers 56, 58 in the first bypass circuit 77. Thus,
the variable compartments 62, 63 are laid on high temperature
heating mode. On the other hand, the electromagnetic valve 76 for
the cooling compartment 61 is usually opened (ON) so that the
evaporator 66 works. Thus, the cooling compartment 61 is always
kept in low temperature cooling mode.
[0056] Under the above condition, from a view point of thermal
energy, the working of the evaporator 66 results in heat radiation
and it is transferred to the heat exchangers 56, 58, whereby the
total energy for the vending machine is reduced and saved.
[0057] In operation in the summer mode as shown in FIG. 7, the
electromagnetic valves 71, 73, 75 are opened (ON) thereby urging
the cooling work of the evaporators 67, 68, and the electromagnetic
valves 72, 74 are closed (OFF) thereby ceasing the work of the heat
exchangers 56, 58 in the first bypass circuit 77. Thus, the
variable compartments 62, 63 are laid on low temperature cooling
mode.
[0058] As a modified embodiment, supplementary electrical heaters
64 can be disposed within the variable compartments 62, 63 so that
ON and OFF operations are effected by an electrical switch 69.
Further, it may be advantageous to arrange cooling fans 80 near the
condenser 54, heat exchangers 56, 58 and supplementary heaters 64,
since these positions are laid on high temperature conditions
during the operation.
* * * * *