U.S. patent application number 11/654649 was filed with the patent office on 2007-10-18 for temperature control apparatus.
This patent application is currently assigned to DAYTONA CONTROL CO. LTD.. Invention is credited to Shintaro Hayashi, Mitsuo Koizumi, Osamu Urakawa.
Application Number | 20070240871 11/654649 |
Document ID | / |
Family ID | 38603742 |
Filed Date | 2007-10-18 |
United States Patent
Application |
20070240871 |
Kind Code |
A1 |
Hayashi; Shintaro ; et
al. |
October 18, 2007 |
Temperature control apparatus
Abstract
A temperature control apparatus including a temperature control
head kept in contact with an electronic device as a testing object
thermally, an electric heater attached to the temperature control
head, a refrigerant passage formed within the temperature control
head so as to run through inside thereof, a compressor which
compresses refrigerant coming out of the temperature control head,
a temperature sensor which detects a temperature of refrigerant on
an outlet side of the compressor, a condenser which condenses
refrigerant coming out of the compressor, a returning portion which
returns refrigerant condensed by the condenser to the temperature
control head, and a control portion which bypasses the condensed
refrigerant to the intake side of the compressor by a predetermined
quantity corresponding to an output of the temperature sensor.
Inventors: |
Hayashi; Shintaro;
(Yokohama-shi, JP) ; Urakawa; Osamu;
(Yokohama-shi, JP) ; Koizumi; Mitsuo;
(Fukushima-shi, JP) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
DAYTONA CONTROL CO. LTD.
Yokohama-shi
JP
|
Family ID: |
38603742 |
Appl. No.: |
11/654649 |
Filed: |
January 18, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11405423 |
Apr 18, 2006 |
|
|
|
11654649 |
|
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|
Current U.S.
Class: |
165/253 ;
165/61 |
Current CPC
Class: |
F25B 2700/21 20130101;
F25B 2400/0411 20130101; F25B 2400/01 20130101; F25B 2600/2513
20130101; F25B 2400/0409 20130101; G01R 31/2874 20130101; F25B
41/20 20210101; F25B 2700/21152 20130101; F25B 2600/2501
20130101 |
Class at
Publication: |
165/253 ;
165/61 |
International
Class: |
F25B 29/00 20060101
F25B029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 18, 2006 |
MY |
PI 20061763 |
Apr 18, 2006 |
SG |
200602464-0 |
Claims
1. A temperature control apparatus comprising: a temperature
control head kept in contact with an electronic device as a testing
object thermally; an electric heater attached to the temperature
control head; a refrigerant passage formed within the temperature
control head so as to run through refrigerant inside thereof; a
compressor which compresses the refrigerant coming out of the
temperature control head; a temperature sensor which detects a
temperature of refrigerant on an outlet side of the compressor; a
condenser which condenses refrigerant coming out of the compressor;
a returning portion which returns refrigerant condensed by the
condenser to the temperature control head; and a control portion
which bypasses the condensed refrigerant to an intake side of the
compressor by a predetermined quantity corresponding to an output
of the temperature sensor.
2. The temperature control apparatus according to claim 1, further
comprising a bypass line for supplying the refrigerant at the
outlet side of the compressor to the temperature control head by
bypassing the condenser.
3. The temperature control apparatus according to claim 2, wherein
the bypass line includes a control valve for controlling flow rate
of the refrigerant from the compressor.
4. The temperature control apparatus according to claim 1, wherein
the control portion includes means for bypassing the refrigerant
when an output temperature value of the temperature sensor exceeds
the upper limit value of the temperature of refrigerant on the
outlet side of the compressor set preliminarily as a result of
comparison of the output temperature value of the temperature
sensor with the upper limit value of the refrigerant
temperature.
5. The temperature control apparatus according to claim 4, wherein
the control portion which bypasses the refrigerant includes a
bypass passage that communicates the outlet side of the condenser
to the intake side of the compressor and means for turning ON/OFF
refrigerant flowing through the bypass passage by means of the
control portion.
6. The temperature control apparatus according to claim 1, wherein
the control portion includes a system controller for PID
control.
7. A temperature control apparatus comprising: a temperature
control head kept in contact with an electronic device as a testing
object thermally; an electric heater attached to the temperature
control head; a refrigerant passage formed within the temperature
control head so as to run through refrigerant inside thereof; a
first temperature sensor which detects a temperature of the
electronic device; a compressor which compresses refrigerant coming
out of the temperature control head; a second temperature sensor
which detects a temperature of refrigerant on the outlet side of
the compressor; a condenser which condenses refrigerant coming out
of the compressor; a returning portion which returns refrigerant
condensed by the condenser to the temperature control head; and a
control portion which controls the temperature of the electronic
device by controlling the quantity of electricity supplied to the
electric heater and the quantity of refrigerant flowing through the
refrigerant passage corresponding to an output of the first
temperature sensor and controls the quantity of condensed
refrigerant bypassed to the inlet side of the compressor according
to an output of the second temperature sensor.
8. The temperature control apparatus according to claim 7, further
comprising a bypass line for supplying the refrigerant at the
outlet side of the compressor to the temperature control head by
bypassing the condenser.
9. The temperature control apparatus according to claim 8, wherein
the bypass line includes a control valve for controlling flow rate
of the refrigerant from the compressor.
10. The temperature control apparatus according to claim 7, wherein
the control portion includes means for bypassing the refrigerant
when an output temperature value of the second temperature sensor
exceeds the upper limit value of the temperature of refrigerant on
the outlet side of the compressor set preliminarily as a result of
comparison of the output temperature value of the second
temperature sensor with the upper limit value of the refrigerant
temperature.
11. The temperature control apparatus according to claim 10,
wherein the means for bypassing includes a bypass passage that
communicates the outlet side of the condenser to the intake side of
the compressor and means for turning ON/OFF refrigerant flowing
through the bypass passage by means of the control portion.
12. The temperature control apparatus according to claim 7, wherein
the control portion includes a system controller for PID
control.
13. A temperature control apparatus comprising: a temperature
control head kept in contact with an electronic device as a testing
object thermally; an electric heater attached to the temperature
control head; a refrigerant passage formed within the temperature
control head so as to run through refrigerant inside thereof; a
first temperature sensor which detects a temperature of the
electronic device; a compressor which compresses refrigerant coming
out of the temperature control head; a second temperature sensor
which detects a temperature of refrigerant on the outlet side of
the compressor; a condenser which condenses refrigerant coming out
of the compressor; a returning portion which returns refrigerant
condensed by the condenser to the temperature control head; a
bypass portion including first and second bypass passages connected
in parallel to each other for returning the refrigerant condensed
by the condenser to the compressor by bypassing the temperature
control head; a first control portion which controls the
temperature of the electronic device by controlling the quantity of
electricity of the electric heater, the quantity of refrigerant
flowing through the first bypass passage and the quantity of
refrigerant flowing through the refrigerant passage in the
temperature control head corresponding to an output of the first
temperature sensor; and a second control portion which controls the
temperature of the refrigerant on the intake side of the compressor
by controlling the quantity of refrigerant flowing through the
second bypass passage corresponding to the output of the second
temperature sensor.
14. The temperature control apparatus according to claim 13,
wherein the second control portion includes means for bypassing the
refrigerant to the second bypass passage when an output temperature
value of the second temperature sensor exceeds the upper limit
value of the temperature of refrigerant on the outlet side of the
compressor set preliminarily as a result of comparison of the
output temperature value of the temperature sensor with the upper
limit value of the refrigerant temperature.
15. The temperature control apparatus according to claim 13,
wherein the means for bypassing includes an electromagnetic valve
provided on the second bypass passage and means for turning ON/OFF
the refrigerant flowing through the second bypass passage by means
of the electromagnetic valve.
16. The temperature control apparatus according to claim 13,
wherein at least one of the first and second control portions
includes a controller for PID control.
17. The temperature control apparatus according to claim 13,
further comprising a bypass line for supplying the refrigerant at
the outlet side of the compressor to the temperature control head
by bypassing the condenser.
18. The temperature control apparatus according to claim 17,
wherein the bypass line includes a control valve for controlling
flow rate of the refrigerant from the compressor.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a Continuation-in-Part application of U.S. patent
application Ser. No. 11/405,423, filed Apr. 18, 2006, the entire
contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a temperature control
apparatus, and particularly to a temperature control apparatus for
controlling the temperature of an electronic device at the time of
test.
[0004] 2. Description of the Related Art
[0005] Prior to shipment, performance test of an electronic device,
for example, a semiconductor chip needs to be carried out at a room
temperature or a higher temperature or a lower temperature. When
the performance test of a semiconductor chip is carried out at a
room temperature under a rated current, heat is generated inside
the semiconductor chip by this current so that the temperature of
the chip is raised more than the room temperature. Thus, the
semiconductor chip needs to be cooled appropriately to maintain the
temperature at the room temperature. When the semiconductor chip is
heated with a heater or the like in case of high temperature test,
it needs to be cooled appropriately in order to prevent the
temperature from being raised more than a setting temperature.
These cases of cooling are carried out with a temperature setting
head loaded with a semiconductor chip connected to a predetermined
cooling system.
[0006] As a conventional temperature control apparatus, a
temperature control apparatus disclosed in, for example, U.S. Pat.
No. 6,668,570 has been known. This conventional apparatus, as shown
in FIG. 1 of this patent document, executes temperature control of
an electronic device 10 by a thermal head 14 which combines a
passage 36 in which refrigerant flows with an electric heater 30 in
contact with the electronic device 10. In a cooling system using
the thermal head 14 having such a structure, heat is generated from
the electronic device 10 and the heater 30 and this heat is
absorbed by the cooling system. Therefore, when the amount of heat
generated from the thermal head increases at the time of high
temperature test, for example, the quantity of heat absorbed by
refrigerant in the thermal head 14 increases so that the
temperature of refrigerant supplied to a compressor 32 rises. As a
result, the temperature in the compressor 32 is raised by heat
generated therein when refrigerant is compressed and if this
temperature exceeds a setting maximum temperature of the compressor
32, a large thermal stress is applied to components inside the
compressor 32, so that the compressor 32 may be possibly damaged.
Therefore, the quantity of heat generated from the heater 14 needs
to be controlled strictly in order to prevent this serious
phenomenon. This leads to increase in cost of the entire
temperature control apparatus and a temperature controllable range
between the lower limit and upper limit of the temperature control
narrows, thereby limiting an electronic device which can be tested
to particular ones.
BRIEF SUMMARY OF THE INVENTION
[0007] According to one aspect of the present invention, there is
provided a temperature control apparatus comprising: a temperature
control head kept in contact with an electronic device as a testing
object thermally; an electric heater attached to the temperature
control head; a refrigerant passage formed within the temperature
control head so as to run through inside thereof; a compressor
which compresses refrigerant coming out of the temperature control
head; a temperature sensor which detects a temperature of the
compressor; a condenser which condenses refrigerant coming out of
the compressor; a returning portion which returns refrigerant
condensed by the condenser to the temperature control head; and a
control portion which bypasses the refrigerant condensed by the
condenser to an intake side of the compressor by a predetermined
quantity corresponding to an output of the temperature sensor.
[0008] According to another aspect of the present invention, there
is provided a temperature control apparatus comprising: a
temperature control head kept in contact with an electronic device
as a testing object thermally; an electric heater attached to the
temperature control head; a refrigerant passage formed within the
temperature control head so as to run through inside thereof; a
first temperature sensor which detects a temperature of the
electronic device; a compressor which compresses refrigerant coming
out of the temperature control head; a second temperature sensor
which detects a temperature of the compressor; a condenser which
condenses refrigerant coming out of the compressor; a returning
portion which returns refrigerant condensed by the condenser to the
temperature control head; and a control portion which controls the
temperature of the electronic device by controlling the quantity of
electricity supplied to the electric heater and the quantity of
refrigerant flowing through the refrigerant passage corresponding
to an output of the first temperature sensor and controls the
quantity of the condensed refrigerant bypassed to the intake side
of the compressor corresponding to an output of the second
temperature sensor.
[0009] According to further aspect of the present invention, there
is provided with a temperature control apparatus comprising: a
temperature control head kept in contact with an electronic device
as a testing object thermally; an electric heater attached to the
temperature control head; a refrigerant passage formed within the
temperature control head so as to run through refrigerant inside
thereof; a first temperature sensor which detects a temperature of
the electronic device; a compressor which compresses refrigerant
coming out of the temperature control head; a second temperature
sensor which detects a temperature of refrigerant on the outlet
side of the compressor; a condenser which condenses refrigerant
coming out of the compressor; a returning portion which returns
refrigerant condensed by the condenser to the temperature control
head; a bypass portion including first and second bypass passages
connected in parallel to each other for returning the refrigerant
condensed by the condenser to the compressor by bypassing the
temperature control head; a first control portion which controls
the temperature of the electronic device by controlling the
quantity of electricity of the electric heater, the quantity of
refrigerant flowing through the first bypass passage and the
quantity of refrigerant flowing through the refrigerant passage in
the temperature control head corresponding to an output of the
first temperature sensor; and a second control portion which
controls a temperature of the refrigerant on the intake side of the
compressor by controlling the quantity of refrigerant flowing
through the second bypass passage corresponding to the output of
the second temperature sensor.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0010] FIG. 1 is a diagram schematically showing a structure of a
cooling circuit of a temperature control apparatus of an electronic
device including a compressor protection section according to an
embodiment of the present invention;
[0011] FIG. 2 is a structure diagram showing a concrete structure
of the embodiment shown in FIG. 1;
[0012] FIG. 3 is a flow chart for explaining the temperature
control operation of this embodiment; and
[0013] FIG. 4 is a flow chart for explaining the protective
operation of the cooling circuit according to this embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Hereinafter, an embodiment of the present invention will be
described in detail with reference to the accompanying
drawings.
[0015] Referring to FIG. 1, an evaporator 13 is provided within a
temperature control head 12 with which an electronic device 11 as a
testing object such as a semiconductor chip is kept in contact
thermally. An electric heater described later is attached to this
head 12 and a refrigerant passage 14a in which refrigerant flows
through is formed within the evaporator 13. The evaporator 13 is
connected to a cooling circuit including a pipe 15 serving as a
passage of refrigerant. An expansion valve 16 is connected to a
refrigerant intake side of the evaporator 13 and an outlet side
thereof is connected to a compressor 18 through an accumulator 17.
The pressure of refrigerant on the intake side of the expansion
valve 16 is high while the pressure of refrigerant in the
downstream of the evaporator 13 on the outlet is low.
[0016] After passing the temperature control head 12, low pressure
gaseous refrigerant is collected in the accumulator 17 and then fed
to and compressed in the compressor 18. High pressure gaseous
refrigerant compressed by this compressor 18 is condensed by a
condenser 19 on a next step using a fan 20 to form mist-like
refrigerant. The mist-like refrigerant formed in the condenser 19
is a mixture of gaseous refrigerant and condensed refrigerant
particles or small liquid particles of refrigerant. The condensed
mist-like refrigerant is returned to the expansion valve 16 through
the pipe 15 and further returned to the accumulator 17 through a
bypass including an electromagnetic valve 21 and a capillary tube
22. Further, the outlet side of the compressor 18 and intake side
of the expansion valve 16 are connected by a bypass line 23 via an
electromagnetic valve 24, so that the gaseous refrigerant of
high-temperature and high-pressure is mixed with the mist-like
refrigerant flowing through the pipe 15 at the inlet side of the
expansion valve 16.
[0017] The cooling system having such a structure includes a first
temperature sensor T1 for detecting the temperature of the
electronic device 11 in the temperature control head 12 and a
second temperature sensor T2 for detecting the temperature of the
compressor 18. In the case of FIG. 1, the sensor T2 is set at the
outlet side of the compressor for measuring the temperature of the
refrigerant on the outlet side of the compressor 18. The sensor T2
may be provided at the inlet side of the compressor 18 for
measuring the temperature of the refrigerant supplied to the
compressor 18 or may be provided at the inside of the compressor 18
as the temperature of the compressor 18. It further includes a
system controller being described later (not shown in FIG. 1) which
executes, for example, PID control as a control portion for
controlling the temperature of the electronic device 11 by
controlling the quantity of current supplied to the electric heater
and the quantity of refrigerant flowing through the refrigerant
passage 14a corresponding to an output of the first temperature
sensor T1 and controlling the quantity of the condensed refrigerant
bypassing to the intake side of the compressor 18 through the
capillary tube 22 corresponding to an output of the second
temperature sensor T2. The amount of bypassed refrigerant through
the bypass line 23 from the outlet side of the compressor 18 to the
inlet side of the expansion valve 16 is controlled to by constant
by opening the electromagnetic valve 24 at a fixed opening position
determined in accordance with a specification of the electronic
device 11 to be tested. The detailed explanation of the valve
control will be described later.
[0018] The cooling system shown in FIG. 1 may be provided with a
drier DR, a high-pressure gauge G1, a high-pressure pressure switch
P1, an electromagnetic valve S, a service port SP, a ball valve V,
a low pressure gauge G2, a low-pressure pressure switch P2 and the
like corresponding to each purpose.
[0019] Hereinafter, the concrete structure of the cooling system
shown in FIG. 1 will be described with reference to FIG. 2.
[0020] The same reference numerals are attached to components
corresponding to those of FIG. 1. The temperature control head 12
is constructed by combining the evaporator 13 having plural
refrigerant passages 14a and an electric heater 14b. An electronic
device or a semiconductor chip 11 is pressed to the bottom face of
the temperature control head 12 through a high-heat conductive
member 12a. A plurality of solder ball terminals 11a are formed on
the bottom face of the semiconductor chip 11 and the semiconductor
chip 11 is connected to a connecting terminal provided on a socket
10s through this solder ball terminal 11a and further connected to
an outside test unit (not shown) so as to perform a predetermined
test. A probe T1P of the temperature sensor T1 is kept in contact
with the semiconductor chip 11 and a detection output of the
temperature sensor T1 is supplied to a system controller 31 for PID
control. The electric heater 14b provided on the temperature
control head 12 is driven by a heater driver 14bD under a control
of the system controller 31. A computer such as a micro-processor
may be used as the system controller 31 in place of the PID
controller.
[0021] The plurality of refrigerant passages 14a formed within the
evaporator 13 are connected to the refrigerant pipe 15 on the
intake side and the refrigerant pipe 15 on the outlet side. The
refrigerant pipe 15 connected to the outlet side of the temperature
control head 12 is connected to the compressor 18 through the
accumulator 17. A probe T2P of another temperature sensor T2 is
installed on the refrigerant pipe 15 on the outlet side of this
compressor 18 in the present embodiment so as to detect the
temperature of refrigerant on the outlet side of the compressor 18.
As above-mentioned, the probe T2P of the sensor T2 may be provided
at another place such as on the inlet side of inside of the
compressor 18. A detection output of this temperature sensor T2 is
supplied to the system controller 31.
[0022] The refrigerant pipe 15 connected to the outlet side of the
compressor 18 is coupled with the intake side of the condenser 19.
This condenser 19 is a heat radiator and heat of refrigerant is
radiated by blowing air to the radiator 19 with the fan 20 to
condense gaseous refrigerant to mist-like refrigerant. The
refrigerant pipe 15 connected to the outlet side of the condenser
19 is branched to a first branch pipe 15A and a second branch pipe
15B in succession. These first and second branch pipes 15A, 15B
communicate with the refrigerant pipe 15 connected to the intake
side of the accumulator 17 through electromagnetic valves 15AV,
15BV, respectively. These electromagnetic valves 15AV, 15BV are
opened/closed by the system controller 31 under each predetermined
condition, which will be described later.
[0023] The refrigerant pipe 15 connected to the outlet side of the
condenser 19 is connected to the intake side of the electronic
expansion valve 16 provided on the intake side of evaporator
13.
[0024] Further, in the embodiment shown in FIGS. 1 and 2, a bypass
line 23 is provided from the outlet side of the compressor 18 to
the inlet side of the expansion valve 16 for bypassing the
condenser 19. An electromagnetic valve 24 is provided on the bypass
line 23. The bypass line 23 is connected between the refrigerant
pipe 15 at the outlet side of the compressor 18 to another
refrigerant pipe 15 connected from the outlet side of the condenser
19 to the inlet side of the expansion valve 16 via the
electromagnetic valve 24, thereby bypassing the condenser 19. In
the case of FIG. 2, the outlet side of the electromagnetic valve 24
is connected at a point on the pipe 15 provided between the two
bypassing points of the bypass lines 15A and 15B. Further, the
outlet side of the electromagnetic valve 24 may be connected
preferably at a position on the pipe line 15 between the bypassing
point of the bypass line 15B and the expansion valve 16. The
electromagnetic valve 24 is set at a predetermined open position
according to a control signal from the system controller 31.
[0025] Next, the operation of the cooling system having such a
structure shown in FIG. 2 will be described with reference to FIGS.
3 and 4. If the performance test of the electronic device 11 is
carried out at a predetermined temperature higher than the room
temperature, a user sets up a lower limit value STL of a setting
temperature range in the system controller 31. In this case, a
temperature DT of the temperature control head 12 is equal to the
room temperature and a temperature detected by the temperature
sensor T1 through the probe T1P is low when the temperature control
is started. Thus, a result of determination turns to YES in initial
step S1 of FIG. 3 (DT<STL?) and the control proceeds to step S2.
As a consequence, an instruction of "CLOSE" is sent from the system
controller 31 to the expansion valve 16 so that no refrigerant
flows to the evaporator 13 and the valve 15BV turns to "OPEN" to
allow refrigerant to pass through the bypass passage 15B. At the
same time, the heater driver 14bB is driven to supply electricity
to the electric heater 14b, so that the temperature control head 12
is heated up to the test temperature.
[0026] At this time, the electromagnetic valve 24 is set at an open
state with a predetermined open degree and the gaseous refrigerant
of high-temperature and high-pressure from the compressor 18 is
supplied to the inlet side of the expansion valve 16. However,
since the expansion valve 16 is set at the closed state, this
refrigerant bypassed the condenser 19 is not supplied to the
expansion valve 16 but is returned through the bypass line 15B. At
this time, the electronic device 11 being tested is not positioned
in the temperature control head 12. The device 11 is held at the
high testing temperature at a waiting position (not shown). The
open degree of the electromagnetic valve 24 is set at a
predetermined value when the device test is started so that the
temperature of the temperature control head 12 is held within a
predetermined range in response to the heat generated during the
electronic device 11 is tested and the ambient temperature of the
head 12.
[0027] When the temperature DT of the temperature control head 12
exceeds the lower setting temperature STL, a result of
determination in step S1 becomes at NO, the electronic device 11
being tested is put in the temperature control head 12, and the
performance test of the device 11 is executed. During the test, a
predetermined test current flows through the device 11 and heat
will be generated from the device 11, and the control proceeds to
step S3. Here, whether or not the temperature DT of the head 12 or
the electronic device 11 detected by the temperature sensor T1
exceeds the upper limit value STH of the test temperature range
(DT>STH?) is determined. If the result is NO, the control
proceeds to step S4, in which an instruction of "CLOSE" continues
to be given to the electromagnetic expansion valve 16 from the
system controller 31 and a condition in which refrigerant is
blocked from flowing to the evaporator 13 is maintained and the
valve 15BV turns to "OPEN" so that refrigerant continues to pass
through the bypass passage 15B. At the same time, the heater driver
14bD is stopped to drive the electric heater 14b which is turned to
non-driven state, thereby stopping heating of the electronic device
11. On the other hand, a test current is continued to be supplied
to the electronic device 11 and predetermined amount of heat is
generated according to the test current.
[0028] On the other hand, if the temperature of the electronic
device 11 rises too much in the condition of step S3 (DT>STH? is
YES), the control proceeds to step S5, in which an instruction
"OPEN" is supplied from the system controller 31 to the
electromagnetic expansion valve 16 and the mist-like refrigerant
begins to flow into the evaporator 13. At the same time, the valve
15BV turns to "CLOSE" so that refrigerant is blocked from passing
the bypass passage 15B. At this time, the drive condition of the
heat driver 14bD is released so that no current is supplied to the
electric heater 14b and the heating of the electronic device 11 by
the heater 14b is stopped, except for the heating by the interior
heat generated from the electronic device 11. As a result, the
electronic device 11 is cooled by absorption of heat when the
mist-like refrigerant flowing through the evaporator 13 is
evaporated and the temperature DT falls to the lower setting
temperature STL. In this condition, since the electromagnetic valve
24 is set to an open state with a predetermined open degree, the
gaseous refrigerant of high-temperature and high-pressure is
supplied directly to the inlet side of the expansion valve from the
outlet side of the compressor 18 so that the gaseous refrigerant is
mixed with the mist-like refrigerant in the pipe 15. As a result,
the temperature of the mist-like refrigerant supplied to the
temperature control head 12 from the expansion valve 16 is high
compared with a case in which no gaseous refrigerant is supplied
from the pipe 23 via the electromagnetic valve 24. Therefore, when
a high-temperature test of 100.degree. C., for example, is being
executed, it is possible to maintain the test temperature of
100.degree. C. by supplying the high temperature gaseous
refrigerant from the valve 24.
[0029] When DT<STL is obtained, the control is YES in step S1 so
that the same temperature control action is maintained between the
lower and upper temperature setting ranges STL and STH.
[0030] As for the control of the electric heater 14b and the
expansion valve 16, software control by a computer can be executed
instead of hardware control by the system controller 31 by PID.
[0031] When the performance test of the electronic device 11 is
executed at a high temperature higher than the room temperature in
the embodiment of FIG. 2, the user sets the system controller 31 so
that the heater 14b is driven by the heater driver 14bD to generate
heat. In the same time, the temperature of the temperature control
head 12 is set to be high so that the electronic device 11 being
tested is heated at a test temperature, when the test is started.
In the embodiment, the electromagnetic valve 24 is set to be open
when the high-temperature test is started. In this condition, the
electromagnetic valves 15AV, 15BV are closed and the expansion
valve 16 is set to be open.
[0032] When the device performance test is started, the test
current is supplied to the electronic device 11, and the high
temperature gaseous refrigerant delivered at the outlet side of the
compressor 18 is supplied to the pipe 15 at the inlet side of the
expansion valve 16 via the electromagnetic valve 24 in the bypass
line 23. Low temperature mist-like refrigerant flowing in the pipe
15 from the condenser 19 is mixed with the high temperature gaseous
refrigerant flowing into the pipe 15 from the pipe 23 and the mixed
refrigerant is supplied to the expansion valv 16. Thus, after the
test is started, the temperature of the refrigerant at the inlet
side of the expansion valve 16 raises rapidly in the case of the
embodiment shown in FIG. 2. The pressure of the refrigerant is
lowered at the outlet side of the expansion valve 16 and the low
pressure mist-like refrigerant is supplied to the evaporator 13 of
the temperature control head 12. The mist-like refrigerant is
evaporated in the evaporator 13 to regulate and maintain the
temperature of the electronic device 11 at the test temperature.
The temperature in the temperature control head 12 is mainly varied
by the heat generated from the interior of the electronic device 11
during the performance test is executed. Therefore, the temperature
in the head 12 is mainly controlled so as to maintain the
temperature in the head 12 at the test temperature in response to
the temperature change caused by the heat generated from the device
11 under test by appropriately absorbing this heat with the
evaporated refrigerant.
[0033] Since the maximum rated current being supplied to the
electronic device 11 during the performance test thereof is known,
the maximum amount of heat generated from the device can be
estimated. Further, even if the electromagnetic valve 24 is set at
a constant open state, it is possible to maintain the temperature
of the device 11 within a predetermined objective temperature range
by the refrigerant supplied from the expansion valve 16 so that the
refrigerant can absorb the fluctuation of the heat generated from
the device 11, by controlling the heater driver 14bD to supply
corresponding current to the electric heater 14b by the system
controller 31 during the test is executed, In the embodiment shown
in FIG. 2, as above-mentioned, the bypass line 15A including the
electromagnetic valve 15AV is important for protecting the
compressor 18. Thus, the high-temperature test for the electronic
device 11 can be performed with the electromagnetic valve 24 and
the expansion valve 16 are set at the open state during the
execution of the test, thereby enabling the temperature control of
the device 11 under test very easily.
[0034] When the test is being performed at a low temperature, at
25.degree. C. near the room temperature, for example, the electric
heater 14b is not driven and only the heat is generated from the
device 11 during the test is performed. When the supply current to
the device 11 during the test is small, it is not required to cool
the device 11 since little heat is generated. When the supply
current is large, much heat will be generated from the device 11
and the temperature of the device 11 may be varied beyond the set
test temperature range of 25.+-.3.degree. C. When this is occurred,
the electromagnetic valve 24 is closed so that the mist-like low
temperature refrigerant from the condenser 19 is only supplied to
the temperature control head 12 from the expansion valve 16. When
the expansion valve 16 is set at the open state, a constant amount
of refrigerant is supplied to the head 12. The refrigerant is the
mist-like refrigerant which is a mixture of the gaseous refrigerant
and fine particle liquid refrigerant. Therefore, when the high
temperature gaseous refrigerant from the valve 24 is mixed with the
low-temperature mist-like refrigerant, the component of the fine
liquid particle refrigerant in the mixture of the refrigerant
decreases and the cooling ability of the mixture refrigerant may be
lowered in the temperature control head 12. On the contrary, when
the electromagnetic valve 24 is closed in the low-temperature test,
the cooling ability will be increased, since the component of the
fine liquid particle increases. Therefore, even if the heat
generated from the device 11 under test increases abruptly, it is
possible to absorb the heat effectively in the temperature control
head 12 so that the temperature of the device 11 may be maintained
near the test temperature of 25.degree. C.
[0035] Next, the operation of preventing the compressor 18 from
being destroyed by overheat will be described with reference to
FIG. 4. When the temperature control of the electronic device 11 is
carried out with reference to FIG. 3, the refrigerant temperature
RT in the pipe 15 on the outlet side of the compressor 18 is
detected by the probe T2P of the temperature sensor T2 and sent to
the system controller 31. A refrigerant upper limit temperature PT
is set up on the system controller 31 in order to protect the
compressor 18 and whether or not this refrigerant temperature RT is
over the set refrigerant upper limit temperature PT is determined
in step S11.
[0036] When the refrigerant temperature RT is lower than the
refrigerant upper limit temperature PT, the result is NO and the
control proceeds to step S12, in which the electromagnetic valve
15AV on the refrigerant bypass passage 15A is kept in "CLOSE". At
this time, the electromagnetic valve 15BV on the other refrigerant
bypass passage 15B can be opened or closed corresponding to the
temperature DT of the electronic device 11 as described in FIG.
3.
[0037] When the refrigerant temperature RT on the outlet side of
the compressor 18 is higher than the upper limit temperature PT, a
determination result in step S11 is YES and the control proceeds to
step S13. The electromagnetic valve 15AV is opened by a control of
the system controller 31 and refrigerant condensed and cooled by
the condenser 19 flows into the accumulator 17 through the bypass
passage 15A. As a consequence, the temperature RT of refrigerant
supplied from the accumulator 17 to the compressor 18 drops thereby
preventing the compressor 18 from being overheated.
[0038] Drop of the refrigerant temperature RT on the outlet side of
the compressor 18 by opening of the electromagnetic valve 15AV is
continued while the result is NO in step S14 (RT<PT?).
[0039] If the result is YES in step S14 (RT<PT?), the control
proceeds to step S12, in which the electromagnetic valve 15AV is
closed under a control of the system controller 31 so that bypass
refrigerant flowing into the accumulator 17 is vanished. As a
consequence, the refrigerant temperature RT on the outlet side of
the compressor 18 begins to rise again. Control of the refrigerant
temperature on the outlet side of the compressor 18 by
opening/closing of the electromagnetic valve 15AV can be carried
out without affecting the temperature control operation of the
electronic device 11 so much.
[0040] According to this embodiment, as described above, this
temperature does not exceed the setting maximum temperature of the
compressor 18 even if the quantity of heat generated from the
heater 14b increases in a high temperature test so that the
temperature of refrigerant supplied to the compressor 18 rises.
Thus, components in the compressor 18 are protected from a large
thermal stress, thereby protecting the compressor 18 from a damage.
Thus, it is possible to maintain effectively the temperature of the
electronic device 11 under test at the objective test temperature,
even if the test temperature is set at a high temperature or at a
low temperature.
[0041] Therefore, the quantity of heat generated from the heater
14b does not need to be carried out strictly, cost of the entire
temperature control apparatus can be suppressed to a low level, a
temperature controllable range between the lower limit and upper
limit of the temperature control can be secured widely and an
electronic device which can be tested is not restricted to any
particular type.
[0042] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
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