JP2000088730A - Device for controlling electronic expansion valve of refrigerator for cold impact device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten temperature raising time while maintaining the temperature controllability of a low-temperature chamber. SOLUTION: A device for controlling an electronic expansion valve comprises a constant pulse setting part 5 to set a constant pulse P0, a variable pulse computing part 6 to compute a variable pulse Pd according to the difference between the set temperature SV and measured temperature PV of a testing room, a pulse switching part 7 to switch between the pulses so as to deliver P0 after reaching temperature and to deliver Pd while temperature is being raised or lowered, etc. By this, the electronic expansion valve is fixed at an appropriate opening by constant P0 to be simple and stable control while a low-temperature chamber is in a precooled state, and the opening of the electronic expansion valve is changed by Pd which takes a greater or smaller value than P0 while temperature is changing. By this, it is possible to shorten arrival time at low-temperature exposure, or high-temperature or ordinary- temperature exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a test chamber and a pre-cooling chamber which is cooled by an evaporator of a refrigerating circuit having an electronic expansion valve operated by a given pulse, wherein a set temperature of the test chamber is at least low. The present invention relates to an electronic expansion valve control device used for a thermal shock device which is sometimes set to a set temperature condition and a measured temperature is controlled to be a set temperature, and particularly to a technique for shortening a temperature rise / fall time.

[0002]

2. Description of the Related Art A thermal shock apparatus usually includes a high-temperature chamber, a test chamber, and a low-temperature tank, and alternately circulates air between the test chamber, the high-temperature tank, and the low-temperature tank to apply a thermal shock to a sample. Is configured to give. During the high-temperature exposure using the test chamber and the high-temperature tank and the normal-temperature exposure in which the air in the test chamber is circulated with the outside air, the low-temperature tank is precooled so as to be cooled in advance. In this case, in the conventional thermal shock device, a constant pulse smaller than the maximum pulse is fixedly applied to the electronic expansion valve in order to make the temperature control in the pre-cooling operation simple and stable.

However, when the pulse of the electronic expansion valve is fixed as described above, for example, as shown by a two-dot chain line in FIG. 5, at the time of the transition from the normal temperature exposure to the low temperature exposure, the temperature in the test chamber and the pre-cooling chamber equipped with the regenerator are provided. The temperature of the circulating air drops rapidly until the pre-cooling temperature approaches the neutralization temperature, which approaches the same level, but the time from when the circulating air reaches the low temperature of the set temperature increases. In particular, when the sample generates heat, the tendency is increased, and there is a problem that the thermal shock effect given to the sample is reduced.

[0004] For a device such as a refrigerator that has only one temperature control portion and controls the temperature of only that portion to a low temperature, a specific opening control method of the electronic expansion valve has been proposed. (See JP-A-5-141788).

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, maintains good temperature controllability of the pre-cooling chamber of the thermal shock device, shortens the temperature drop time, and reduces the thermal shock performance. An object of the present invention is to provide an electronic expansion valve control device that improves the performance.

[0006]

In order to solve the above-mentioned problems, the present invention comprises a test chamber and a pre-cooling chamber cooled by an evaporator of a refrigeration circuit having an electronic expansion valve operated by a given pulse. An electronic expansion valve control device for use in a thermal shock device, wherein the set temperature of the test chamber is set to a temperature condition including at least a low temperature condition and the measured temperature may be controlled to be the set temperature. A constant pulse setting unit that sets a pulse applied to the valve to a constant pulse, and a variable pulse calculator that calculates a variable pulse corresponding to a difference between the set temperature and the measured temperature, the variable pulse being applied to the electronic expansion valve. When the temperature in the test chamber is substantially constant, the electronic expansion is performed so that the constant pulse is applied, and when the temperature in the test chamber is reduced to the low temperature condition, the fluctuation pulse is applied. And having a pulse switching unit for switching the pulse to be applied to the valve.

[0007]

FIG. 1 shows an example of the configuration of an electronic expansion valve control device to which the present invention is applied and its related devices.
Shows an example of the structure of the main body of the thermal shock device to which this can be attached. The main body portion 100 of the thermal shock device in which the electronic expansion valve control device is used is surrounded by a heat insulating wall 101, in which a test room 1 and a high-temperature tank 2 located on both sides thereof and a low-temperature A tank 3 is provided. Except for the openings, the test chamber 1 and the tanks 2 and 3 are partitioned by a heat insulating wall 101. The openings on the high-temperature tank side and the low-temperature tank side have inlet / outlet dampers 11 for circulating air, respectively. / 12 and 1
3/14 is mounted. Further, in this example, an inlet / outlet damper 15/16 for room temperature exposure is provided, and a blower for room temperature exposure (not shown) is provided outside the main body so that outside air can be taken in and out of the test chamber 1 through these dampers. . Reference numeral 17 denotes two temperature sensors mounted on the upper part of the test chamber 1. The test chamber 1 contains a sample W to be tested, such as an electronic component.

The high-temperature tank 2 and the low-temperature tank 3 include blowers 21 and 31 for the high-temperature tank and the low-temperature tank, their driving motors 21a and 31a, the heater and the heater 2 for controlling the temperature, respectively.
2 and 32, partition plate 23 / forming a duct for circulation in the tank
33, temperature sensors 24, 34, 37, etc. are provided. The low-temperature tank is further provided with a regenerator 35 capable of holding a low calorific value and an evaporator 36 constituting the refrigeration circuit 4.
In FIG. 1, the high-temperature exposure state is indicated by a solid line, and the low-temperature exposure state is indicated by a two-dot chain line. Between these, the damper is switched, and the circulation path of the high-temperature air and the low-temperature air is switched.

Although not shown in FIG. 2 except for the evaporator 36, the refrigeration circuit 4 is disposed in a machine room outside the main body 100, and is arranged in the order of the flow of the refrigerant.
6. The compressor 41, the condenser 42, the electronic expansion valve 43 and the like are formed as main structural parts. A pulse signal is given to the electronic expansion valve, and the refrigerant flows into the evaporator 36 at an opening corresponding to the pulse signal to cool the low-temperature tank 3.

The electronic expansion valve control device is, in this example, an operation control panel 20 disposed outside the main body 100 of the thermal shock device.
0, and includes a constant pulse setting unit 5, a variable pulse calculation unit 6, a pulse switching unit 7, and the like. The operation control panel 200 is provided with a test condition setting unit 201 for a thermal shock test and other ordinary operation buttons and control circuits (not shown). In Test condition setting unit 201, a high temperature T _H, and allow an input of a low temperature T _L and room temperature T _N, the test conditions, the ambient temperature T _N and the low temperature T _L at regular time intervals as shown in FIG. 3, for example Are set in order, and a thermal shock test consisting of normal temperature exposure-low temperature exposure is performed. As a result, the temperature can be cycled between any two or all of T _H , T _L, and T _N to perform the thermal shock test of the sample W.

[0011] is a constant pulse setting unit 5, and transmits it to set the pulse to be supplied to the electronic expansion valve 43 to a constant pulse P _0. The constant pulse P ₀ is determined in accordance with a set low-temperature temperature condition, a high-low temperature difference, a pre-cooling temperature, a heat release amount of a pre-cooling room, a heat amount of reheating for temperature control, and the like. Under the test conditions, the value is considerably smaller than the maximum pulse, and the refrigerator is operated at a capacity lower than the maximum refrigeration capacity.

The fluctuation pulse setting unit 6 is adapted to provide the electronic expansion valve 43 with the fluctuation pulse Pd.
In this example, as a fluctuation pulse corresponding to the difference between the set temperature SV of the test chamber 1 set at 01 and fluctuating in a constant cycle as described above and the measured temperature PV actually measured by the temperature sensor 17 in the test chamber 1, A fluctuation pulse P obtained by adding a correction pulse Pc calculated according to the difference to the constant pulse P ₀
Calculate d = P ₀ + Pc. Therefore, the measured temperature PV and the set temperature SV are sent to the fluctuation pulse setting unit 6 from the temperature sensor 17 and the test condition setting unit 201, respectively.

The correction pulse Pc can be calculated by an appropriate method. In this embodiment, the correction pulse Pc is calculated by the following equation: Pc = [PV− (SV + OF)] × n −− (1) Here, OF is provided to prevent temperature overshoot and undershoot by offset, and n is a coefficient of comparison between the temperature difference and the pulse (number of pulses / ° C.), both of which can be finely adjusted. . Incidentally, according to the above equation, Pc becomes positive at the time of temperature drop, Pd is larger than P _0, the opening degree of the electronic expansion valve 43 is increased.

The above equation is applied only when the temperature drops, and the variable pulse calculator 6 may be applied only when the temperature drops. In this example, however, as will be described later. The same equation is applied to the temperature rise. At this time, it is calculated by the following equation: Pc = [PV− (SV−OF)] × n −− (2) In this case, since PV is smaller than SV and Pc is minus, by reducing OF, temperature overshoot and undershoot are prevented. Since Pc is negative as described above at the time of temperature rise, Pd is smaller than P _0, the opening degree of the electronic expansion valve 43 is reduced.

The pulse switching section 7 gives a certain pulse P ₀ when the inside the test chamber 1 is operated at a substantially constant temperature becomes either bleached temperature, the temperature drop of at least the test chamber 1 to the low temperature condition T _L When it is performed, the pulse given to the electronic expansion valve 43 is switched so as to give the fluctuation pulse Pd. In this example, Pd is used even when the temperature rises as described above.

As the signal for switching as described above to be given to the pulse switching unit 7, an appropriate signal which can distinguish between during and after temperature change, such as a comparison value between SV and PV, a change rate of PV, and the like, is used. Can be In this example, the value of (PV−SV) is received from the fluctuation pulse calculation unit 6 and the pulse switching unit 7
≒ It is determined whether the temperature is rising or falling or after the temperature has reached by the expression PV or the absolute value (PV-SV) <α. α is a small value. Then, T _H, the constant exposure temperature after any temperature reaches the T _L or T _N, passed through a constant pulse P ₀ is sent to the electronic expansion valve 43, if in variation between exposure temperature, P _It is switched to pass Pd instead of ₀ .

In the above description, the fluctuation pulse Pd is set to (P ₀ +
Although calculated as Pc), it is also possible to calculate the variable x in accordance with the difference between SV and PV by a calculation formula such as Pd = xP ₀ . In the above description, (PV-SV) is used as the difference between SV and PV, but another calculation method such as SV / PV can be used.

The above-described electronic expansion valve control device and the thermal shock device to which the electronic expansion valve control device is applied are operated as follows, and the operation and effect thereof are exhibited. For example, in the thermal shock test between the normal temperature and the low temperature, the test condition setting unit 201 inputs the normal temperature T _N = 25 ° C. which is the normal temperature exposure temperature and the low temperature T _L = −65 ° C. which is the low temperature exposure temperature. At this time, the dampers 11 to 14 are closed, the inlet / outlet damper 15/16 for the room temperature exposure air is opened, and the external room temperature exposure blower sends the outside air from the damper 15 into the test chamber 1 and hits the sample W while hitting the sample W. It is discharged from 16. In the high-temperature bath 2, the blower 21 and the heater 22 are in an operation stop state.

[0019] The electronic expansion valve 43 constant pulse P ₀ is sent, the refrigerant flows in the opening corresponding thereto. Low temperature bath 3
Inside, the blower 31 is operated, the air is cooled by the evaporator 36, and is heated by the heater 32 to control the temperature while the regenerator 3 is cooled.
5, a pre-cooling operation is performed to cool the inside of the container 5 and maintain the inside at -80 ° C. The output of the heater 32 is controlled by detecting the temperature of a temperature sensor 34. In this state, since there is no heating load from the sample in the cryostat 3, to retain a constant pulse P ₀ by cooling and reheating and by appropriate refrigeration capacity corresponding to, good controllability precooling temperature with low power consumption it can.

In this state, when a predetermined time elapses and the set temperature SV is set to the low temperature _TL to shift to low temperature exposure,
The normal temperature air inlet / outlet damper 15/16 closes and the normal temperature exposure blower stops, the inlet / outlet damper 13/14 to the low temperature tank 3 opens, and the air precooled by the blower 31 is sent into the test chamber 1. . As a result, the temperature in the test chamber 1 drops rapidly and reaches the neutralization temperature Tm in a short time.

On the other hand, when the SV is set to T _L , a large temperature difference (PV-SV) occurs between the SV and the PV detected by the temperature sensor 17. As a result, the fluctuation pulse setting unit 6 of the electronic expansion valve control device calculates the correction pulse Pc and the fluctuation pulse Pd = P ₀ + Pc by equation (1). Further, since the temperature difference increases, the pulse switching unit 7 so determined that during the temperature drop, pass switches the P ₀ to Pd. The electronic expansion valve 43 has P ₀
A pulse that is larger and initially near the maximum pulse is sent. As a result, the refrigerating capacity is increased, and the temperature drop in the test chamber 1 is promoted. In this case, even if the sample W has an exothermic load, the temperature of the test chamber 1 can be rapidly lowered while processing the exothermic load due to the large refrigerating capacity.

When the measured temperature PV reaches the set temperature SV, the low-temperature exposure for a predetermined time is continued, and PV ≒
By become SV, the pulse switching unit 7 passes the P ₀ in place of Pd is judged to have reached the set temperature. After reaching the temperature, the refrigeration capacity only needs to maintain the low-temperature exposure temperature of -80 ° C. Thus, by reducing the pulse and narrowing the valve opening, it is possible to obtain energy-saving operation and good controllability. Can be. After the low temperature exposure time has elapsed, the normal temperature T _N is set for normal temperature exposure. This allows
The inlet / outlet damper 13/14 to the low temperature tank 3 is closed, the room temperature air inlet / outlet damper 15/16 is opened, and the blower for room temperature exposure is operated, so that room temperature air flows into the test chamber 1 and passes therethrough. As a result, the temperature in the test chamber 1 rises rapidly.

On the other hand, when SV is set to T _N , a large temperature difference (PV-SV) is generated as a negative value from PV detected by the temperature sensor 17 this time. Accordingly, the fluctuation pulse setting unit 6 of the electronic expansion valve control device calculates the correction pulse Pc and the fluctuation pulse Pd = P ₀ + Pc by equation (2). In this case, Pc has a negative value. Further, since the temperature difference increases, the pulse switching unit 7 is the numerical value is placed, passing by switching the P ₀ to Pd. The electronic expansion valve 43 has P ₀
An even smaller fluctuation pulse Pd is sent. as a result,
The refrigeration capacity is reduced, and the low-temperature tank 3 has a low-temperature exposure temperature of -65.
The transition from the pre-cooling temperature to a lower pre-cooling temperature of −80 ° C. becomes slower, and the lowering of the temperature of the low-temperature tank 3 suppresses the test chamber 1.
Is returned to room temperature. In addition, the refrigeration capacity brought out by the room temperature air is reduced, and energy is saved.

When the measured temperature PV reaches the set temperature SV, exposure to normal temperature for a predetermined time is continued, and PV 、
Pulse switching unit 7 by becoming SV passes the P ₀ in place of Pd. As a result, after reaching the set temperature, the refrigeration capacity returns to an appropriate level for pre-cooling the inside of the low-temperature bath 3 and the low-temperature bath is pre-cooled under favorable conditions in preparation for the next low-temperature exposure.

In a thermal shock test between a high temperature and a low temperature, a high temperature exposure temperature T _H = 160 ° C. and a low temperature T _L = −65 ° C. are input to the test condition setting unit 201 in the same manner. At this time, first, all the dampers 11 to 11
16 is closed, and a blower 21 and a heater 22
Is operated, air is circulated, and the inside is preheated to 175 ° C., for example. The low-temperature tank 3 is also pre-cooled in the same manner as described above. Then, the high temperature side and low temperature side dampers are alternately opened and closed at predetermined time intervals, and the high temperature exposure and the low temperature exposure are repeatedly executed.

[0026] Also in this case, the electronic expansion valve control device operates in the same manner, at the time of temperature raising and lowering of the test chamber 1 to open and close the electronic expansion valve 43 at a variable pulse Pd, and after the temperature reaches the opening of the fixed pulse P ₀ I do. The same effects as in the case of normal temperature-low temperature exposure, such as shortening of the temperature arrival time, good precooling control without hunting, energy saving, etc., can be obtained.

In the thermal shock device, a test of high temperature exposure-normal temperature exposure may be performed. At this time, the operation of the refrigeration circuit 4 and the low-temperature tank 3 are usually stopped. However, when the operation of the refrigeration circuit is to be continued due to a request for continuity of operation or the like, the electronic expansion valve control device of the present embodiment can be applied. In this case, adjustment of the refrigerating capacity by the electronic expansion valve control device of the present embodiment indirectly assists the temperature transition between high temperature and normal temperature.

FIG. 4 shows an example of the results of an experiment conducted by the inventors. In the figure, “when the pulse is variable” on the left is the operation result using the electronic expansion valve control device of this example, and “when the pulse is fixed” on the right is the operation result using the conventional device, which was performed for comparison. As shown in the drawing, when the exposure is changed from the normal temperature exposure of 25 ° C. to the low temperature exposure of −65 ° C., in the conventional apparatus, a constant pulse P _{0 of} about 70% of the maximum pulse N is given to the electronic expansion valve, and the temperature drop time Was 12 minutes,
In the apparatus of this example, the fluctuation pulse Pd immediately rises to a value close to the maximum pulse N after the setting change from the normal temperature to the low temperature, the temperature drop is accelerated, and the temperature drop time is shortened by 2 minutes as compared with the conventional apparatus. It was 10 minutes. As a result, it was possible to improve the thermal shock performance and shorten the test time.

[0029]

As described above, according to the present invention, since the constant pulse setting section is provided for setting the pulse applied to the electronic expansion valve to a constant pulse, the constant pulse is set to an appropriate value corresponding to the set low temperature condition. In the pre-cooling operation in which the pre-cooling chamber is kept at a constant temperature, the temperature in the pre-cooling chamber can be easily and accurately controlled by the usually provided heater for temperature control. At this time, since there is no heat load from the sample in the pre-cooling chamber, it is not necessary to set the constant pulse to a large value. Therefore, energy saving during operation can be achieved.

Further, since a fluctuating pulse calculator for calculating a fluctuating pulse corresponding to the difference between the set temperature and the measured temperature is provided, the temperature of the test chamber is reduced to a low temperature, for example, to lower the temperature from a normal temperature condition to a low temperature condition. When it is set, it is possible to calculate a fluctuating pulse so as to be larger than a certain pulse, and to apply the fluctuating pulse to the electronic expansion valve to increase its opening.

Switching means for switching the pulse applied to the electronic expansion valve is provided so that a constant pulse is given when the test chamber is operated at a constant temperature, and a variable pulse is given at least when the temperature of the test chamber is lowered to a low temperature condition. Since it is provided, during the pre-cooling operation of the pre-cooling chamber as described above, the refrigerating capacity is kept constant, and the temperature in the pre-cooling chamber can be accurately controlled by a temperature control heater normally provided in the pre-cooling chamber, and at the time of temperature drop, The opening degree of the electronic expansion valve is increased by the fluctuation pulse that is larger than the fixed pulse, the cooling capacity of the refrigerator is increased, and the time to reach the low temperature condition can be shortened. In particular, when there is heat generation from the sample, the temperature drop time becomes longer. In this case as well, the time required to reach a lower temperature can be shortened, and the performance as a thermal shock device can be maintained satisfactorily.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of the overall configuration of an electronic expansion valve control device and related parts to which the present invention is applied.

FIG. 2 is a sectional view showing an example of a thermal shock device to which the above device can be applied.

FIG. 3 is a cycle diagram of normal temperature exposure-low temperature exposure by the above apparatus.

FIG. 4 is an explanatory diagram showing experimental results using the above-described apparatus and a conventional apparatus.

FIG. 5 is an explanatory diagram showing a temperature change state between normal temperature exposure and low temperature exposure in the case of conventional electronic expansion valve control.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Test room 3 Low-temperature tank (pre-cooling room) 4 Refrigeration circuit 5 Constant pulse setting part 6 Fluctuation pulse calculation part 7 Pulse switching part 36 Evaporator 43 Electronic expansion valve 100 Main part (Cold and thermal shock device) P ₀ Constant pulse Pc Correction pulse Pd Fluctuating pulse SV set temperature PV measured temperature _TL low temperature (low temperature condition) _TH , _TN high temperature, normal temperature (temperature condition)

Claims (1)

[Claims] 1. A test chamber and a pre-cooling chamber cooled by an evaporator of a refrigerating circuit having an electronic expansion valve operated by a given pulse, wherein the test chamber is set to a temperature condition including at least a low temperature condition. In an electronic expansion valve control device used for a thermal shock device that may be controlled so that a measured temperature is set to a set temperature, a constant pulse setting unit that sets a pulse given to the electronic expansion valve to a constant pulse. A variable pulse calculator for calculating a variable pulse applied to the electronic expansion valve, the variable pulse corresponding to a difference between the set temperature and the measured temperature; and the constant pulse when the temperature in the test chamber is substantially constant. And a pulse switching unit that switches a pulse applied to the electronic expansion valve so as to provide the fluctuation pulse when the temperature in the test chamber is reduced to the low temperature condition. Electronic expansion valve control device which is characterized in that.