KR101849692B1 - Cooling water temperature control system precisely and precisely control the cooling water temperature method using an overflow-type multi-stage dilution - Google Patents

Abstract

The present invention relates to a cooling water temperature precise control system using an overflow multi-stage dilution method, comprising: a first temperature sensor installed in a supply pipe connected to a heat exchanger and selectively controlling a supply temperature of cooling water flowing from a cooling or heating load side; A first dilution tank connected to the supply line to receive and store the cooling water, and having an inlet pipe at a position on the highest level stratum; A second diluting tank connected to the first diluting tank so that the cooling water flowing into the first diluting tank is stored at a lower level than the highest water level of the first diluting tank; A third dilution tank connected to the second dilution tank so that the cooling water flowing over the uppermost level stratum of the first dilution tank is stored over the cooling water introduced into the second dilution tank; A fourth dilution tank connected to the third dilution tank so that the cooling water introduced into the third dilution tank flows downward and is stored; And a main pump connected to a lower portion of the fourth dilution tank and supplying cooling water to the cooling or heating load side.
According to this, the cooling water supplied to the cooling / storing tank at a temperature lower than the set temperature through the heat exchanger is stagewise flowed through the divided first to fourth dilution tanks, and the cooling water of the first and third dilution tanks is selectively The temperature of the final cooling water supplied to the cooling or heating load side can be precisely controlled within the range of 占 0.05 占 폚 to 0.1 占 폚.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling water temperature control system and a cooling water temperature control system using the multi-stage dilution method,

The present invention relates to a cooling water temperature precise control system using an overflowing multi-stage dilution system which is capable of precisely controlling a cooling water temperature by using a multi-stage dilution method of overflowing a cooling water temperature circulating through a heat exchanger and a cooling or heating load region, Temperature precision control method.

Generally, it is essential to precisely control the temperature of the cooling water circulated through the heat exchanger in a cooling and heating system applied to manufacture a laboratory or printed circuit board.

Generally, as a constitution for precisely controlling the temperature of the cooling water, the cooling water is stored in the water tank, and the cooling water temperature supplied to the set temperature or less through the heat exchanger is maintained at the set temperature, and then supplied to the cooling or heating load side through the main pump.

However, in the related art, since the water tank for storing cooling water is composed of a single water tank for storing a large amount of cooling water, it takes a long time to maintain the temperature of the cooling water stored therein to the set temperature. There is a problem that a large temperature deviation occurs.

Accordingly, there is a limit to precisely control the temperature of the cooling water supplied to the cooling or heating load side to a temperature of 占 .05 占 폚 to 0.1 占 폚.

Korean Patent No. 10-0759036 Korea Utility Model Registration No. 20-0377788

SUMMARY OF THE INVENTION The present invention has been made in order to solve the conventional problems as described above, and it is an object of the present invention to provide a cooling water storage tank, The cooling water temperature precise control system and the cooling water temperature precision control system using the overflowing multi-stage dilution system in which the final cooling water temperature supplied to the cooling or heating load side can be precisely controlled within ± 0.05 ° C to 0.1 ° C, Control method.

According to a preferred embodiment of the cooling water temperature precise control system using the overflowing multistage dilution system of the present invention, in a conventional cooling water temperature control system circulating the heat exchanger and the cooling or heating load region and controlling the cooling water temperature,
A first temperature sensor installed in a supply pipe connected to the heat exchanger and controlling the operation of the heat exchanger to change the cooling water to a set temperature after detecting a cooling water supply temperature flowing from the cooling or heating load side; A first partition and a second partition are provided in a 'T' shape on one side of the inside of the water tank body, the upper end of the first partition is the same as the position of the inlet, A first diluting tank disposed at an inner side of the first partition toward the inlet, the upper end of the first partition being formed lower than the upper end of the second partition; A second diluter located outside the first partition to face the first diluter; A third partition wall having an upper end formed to be higher than an upper end of the second partition and spaced apart from the second partition in parallel to the second partition and having a plurality of through holes extending from a central portion of the surface to a lower portion, A third diluting tank disposed at one side of the third partition wall facing the two partition walls; A fourth diluting tank located on the other side of the third partition to face the third dilution tank; And a main pump connected to a lower portion of the fourth dilution tank through a discharge pipe to supply cooling water to the cooling or heating load side.

According to the present invention, it is possible to further include a circulation pump for forcibly circulating the cooling water of the first dilution tank and the third dilution tank.

According to another aspect of the present invention, the apparatus may further include a second temperature sensor for checking the temperature of the cooling water of the fourth dilution tank and for indicating the temperature of the cooling water supplied to the cooling or heating load side to the outside.

According to a preferred embodiment of the cooling water temperature precise control method using the overflowing multistage dilution method of the present invention, the operation of the heat exchanger is controlled by the first temperature sensor provided on the supply pipe connected to the heat exchanger, Maintaining the temperature of the cooling water flowing from the cooling pipe at a predetermined temperature and supplying the cooling water to the supply pipe; Supplying cooling water having a temperature lower than a set temperature to the first dilution tank through the inflow pipe and storing the same; Circulating the cooling water of the upper layer in the second dilution tank at a level lower than the highest water level of the first dilution tank while keeping the cooling water of the first dilution tank for a predetermined time; Storing the cooling water in the upper layer on the uppermost level stratum of the first dilution tank and overflowing the third cooling water in the third dilution tank while staying the cooling water flowing into the second dilution tank for a predetermined time; Storing the cooling water introduced into the third dilution tank so as to flow into the lower side of the fourth dilution tank while staying therein for a predetermined time; And supplying cooling water to the cooling or heating load side through the main pump connected to the lower portion of the fourth dilution tank.

According to the present invention, the cooling water of the first dilution tank and the third dilution tank may be forcedly circulated through the circulation pump.

According to the present invention, the method further includes the step of externally displaying the temperature of the cooling water of the fourth dilution tank supplied to the cooling or heating load side through the second temperature sensor installed in the fourth dilution tank.

According to the present invention, the cooling water supplied to the cooling / storing tank at a set temperature or lower through a heat exchanger is gradually overflowed through the divided first to fourth diluting baths, and the cooling water of the first and third diluting baths The temperature of the final cooling water supplied to the cooling or heating load side can be precisely controlled within ± 0.05 ° C to 0.1 ° C by the forced circulation through the circulation pump.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a systematic diagram showing a cooling water temperature precise control system and a cooling water temperature precise control method using an overflowing multistage dilution system of the present invention;
FIG. 2 and FIG. 3 are a perspective view and a cross-sectional view showing the structure of a cooling water tank according to an embodiment of the cooling water temperature precise control system using the overflow multi-step dilution method of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

It will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

In addition, the sizes and shapes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation, and the terms defined specifically in consideration of the configuration and operation of the present invention may vary depending on the intention or custom of the user, operator And the definitions of these terms should be based on the contents throughout this specification.

1 to 3, the system for precisely controlling the cooling water temperature using the overflow multi-step dilution method according to an embodiment of the present invention can be configured as follows.

The present invention relates to a method for controlling the temperature of a cooling water, comprising a compressor 10, a condenser 20, an expansion valve 30, a heat exchanger 40, a first temperature sensor S1 and a plurality of dilution chambers 51, 53, 54).

The compressor 10 is connected to the heat exchanger 40 through a pipe and compresses the refrigerant in the heat exchanged with the heat exchange water supplied from a cooling load side (e.g., a laboratory) connected to the heat exchanger 40.

The condenser 20 is connected to the compressor 10 and serves to heat the refrigerant cooled in the compressor 10 by heat exchange with the outside air to condense the refrigerant.

The expansion valve 30 is connected to the downstream end of a receiver (receiver tank) 21 connected to the condenser 20 to temporarily store the refrigerant. The expansion valve 30 reduces the pressure of the refrigerant to a low pressure and controls the refrigerant flow rate before sending the refrigerant to the evaporator.

At this time, a filter driver 22 is connected between the expansion valve 30 and the receiver 21 to absorb the refrigerant water, so that the refrigerant is frozen in the capillary of the expansion valve 30 and the condenser 20 Do not disturb the flow of refrigerant.

The heat exchanger (40) serves to vary the cooling water flowing into the cooling or heating load to the set temperature by receiving the refrigerant depressurized by the expansion valve (30).

A hot gas bypass control valve 23 is provided between the refrigerant supply pipe of the expansion valve 30 and the refrigerant supply pipe of the heat exchanger 40 and the refrigerant return pipe connecting the compressor 10 and the condenser 20, And to control the load between the condensing section and the compression section.

The supply pipe path P1 connected to the heat exchanger 40 and the water tank main body 55 described later is connected to the heat exchanger 40 for sensing the supply temperature of the cooling water flowing from the cooling or heating load side, And the first temperature sensor S1 is provided to vary the cooling water to the set temperature.

The present invention including this basic configuration is a conventional cooling water temperature control system for controlling a cooling water temperature circulating through a heat exchanger and a cooling or heating load region,

A first temperature sensor S1 and a plurality of dilution vessels 51, 52, 53, and 54 for moving the circulating cooling water while staying therein and moving the first and second temperature sensors S1 and S2, ).

The first temperature sensor S1 is installed in a supply pipe P1 connected to the heat exchanger and detects the supply temperature of the cooling water flowing from the cooling or heating load side to control the operation of the heat exchanger to change the cooling water to the set temperature .

The plurality of dilution vessels 51, 52, 53 and 54 may be constituted by individual water tanks, and the cooling water may be circulated in the next dilution tank by the height difference and circulated.

In the present invention, as shown in FIGS. 2 and 3, a large water tank body 55 is partitioned into a plurality of partitions 56, 57 and 58 to supply cooling water to a plurality of dilution vessels 51, 52, And the cooling water temperature is precisely controlled in such a manner that the cooling water is circulated continuously in sequence.

For example, the cooling water temperature supplied to the cooling water tank through the heat exchanger 40 is gradually overflowed as the overflowing multi-step dilution system so that the final cooling water temperature supplied to the cooling or heating load side falls within a range of 占 0 占 폚 to 0.1 占 폚 And is precisely controlled and supplied.

In this embodiment, a configuration in which the interior of one large water tank is divided into a plurality of dilution vessels will be described as an example.

First, the water tank main body 55 has a rectangular parallelepiped shape and has a cooling water inlet 55b supplied from the heat exchanger 40 at the highest water level. Preferably, a heat insulating material (not shown) is provided on the entire outer surface of the water tank main body 55 to minimize the temperature change of the cooling water due to the external temperature.

In the water tank 5, a first dilution tank 51 is connected to the supply pipe P1 to receive and store cooling water, and has an inlet 55b at the uppermost level.

The second diluting tank (51) is connected to the first diluting tank (51) so that the cooling water flowing into the first diluting tank (51) is stored over the lower level of the first diluting tank (51) And the cooling water flowing into the second diluting tank 52 is connected to the second diluting tank 52 so that the cooling water is stored over the highest level stratum of the first diluting tank 51 A third dilution tank 53 is provided and a fourth dilution tank 54 is connected to the third dilution tank 53 so that the cooling water flowing into the third dilution tank 53 flows downward and is stored And a main pump 70 connected to a lower portion of the fourth dilution tank 54 to supply cooling water to the cooling or heating load side.

Specifically, the first diluting tank (51) to the fourth diluting tank (54) may be constructed as follows.

As shown in FIGS. 2 and 3, the one side region of the water tank main body 55 is surrounded by the first partition 56 and the second partition 57, which are installed at intersecting 'T' The first dilution tank (51) and the second dilution tank (52) are provided at one side of the space.

The height of the first partition 56 is equal to the height of the inlet 55b and the height of the second partition 57 is lower than the height of the first partition 56 so that the inlet 55b ) Is provided with the first diluting tank (51) in which cooling water is supplied and stays so as to maintain the temperature below the set temperature through the heat exchanger (40) and the supply pipe path (P1).

The second diluting tank 52 is formed adjacent to the first diluting tank 51 and the cooling water flowing into the first diluting tank 51 is filled in the first diluting tank 51, Becomes a space overflowing over the first partition 56 and staying therein.

The first dilution tank 51 and the second dilution tank 52 are disposed at the center of the water tank main body 55 by the third partition wall 58 spaced in parallel to the second partition wall 57, The third dilution tank 53 is arranged in parallel with the second dilution tank 53.

The cooling water in the upper portion of the first dilution tank 51 and the cooling water flowing in the second dilution tank 52 flow over the third partition wall 58 and stay in the third dilution tank 53.

The third dilutation tank 53 is disposed adjacently to the third dilutation tank 53 with respect to the third partition 58 so that the third dilutation tank 53 can be divided into the third dilutation tank 53, And a fourth dilution tank 54 in which the upper portion is closed, which allows the cooling water flowing over the dilution tank 53 to flow and stay therein downward, is provided.

And a main pump 70 connected to the discharge pipe 55a provided at a lower portion of the fourth dilution tank 54 to supply cooling water maintained at a set temperature to the cooling or heating load side.

According to the flow-through type cooling water circulating member 50 having such a configuration, as described above, cooling water cooled to a set temperature or less through the heat exchanger 40 is first supplied to the first dilution tank 51 through the inlet.

The cooling water filled in the first dilution tank (51) flows over the first dilution tank (52) beyond the first partition (56).

After the cooling water is filled in the first dilution tank 51 and the second dilution tank 52 and filled up to the upper end of the second partition 57, the cooling water is filled and filled in the third dilution tank 53.

At this time, the cooling water filled in the third dilution tank 53 starts to be filled in the fourth dilution tank 54 through the throughflow hole 59. Since the fourth dilution tank 54 has a closed top shape, So that the temperature is constantly maintained after being completely filled up to the inlet line.

 In this state, the cooling water is sequentially supplied to the first diluting tank 51, the second diluting tank 52, the third diluting tank 53, and the fourth diluting tank 54 so as to be sequentially supplied, The temperature of the cooling water can be stored in the water tub main body 55 without rapidly changing to the set temperature.

If the water tank body is composed of a single water tank body, the cooling water supplied below the set temperature is diluted with the cooling water already stored by the convection action inside the single water tank body, so that the set temperature of the cooling water discharged to the main pump It is practically impossible to precisely control the cooling water temperature

However, in the present invention, the cooling water that sequentially flows over the diluting baths 51, 52, 53 and 54 is circulated by the convection action in the respective diluting baths 51, 52, 53 and 54, And then flows from the cooling water in the upper layer of each dilution tank 51, 52, 53 and 54 to the next dilution tank beyond the first partition 56 to the third partition 58.

Accordingly, the cooling water staying in each of the dilution vessels 51, 52, 53 and 54 is cooled by the convection action in the process of staying in each dilution tank, and the temperature of the cooling water in the upper layer is lower than the temperature of the cooling water in the lower layer. If cooling water is continuously supplied to the first diluting tank 51 at a temperature lower than the set temperature through the inlet 55b at this time, the newly introduced cooling water is colder than the cooling water staying in each diluting tank, The cooling water of the upper layer which is to be circulated by the convection action while staying at the lower side of the first dilution tank 52 (51, 52, 53, 54) and is gradually raised to the set temperature above the set temperature, ).

This overflow action gradually rises from the first dilution tank 51 to the third dilution tank 53 while gradually exceeding the first and second diaphragms 56 to 57,

In addition, in the step of passing to the fourth dilution tank 54, the fourth dilution is performed through the plurality of through-holes 59 formed from the middle to the bottom of the third partition 58 without overflowing to the upper side of the third partition 58, As the coolant is pushed downward in the tank 54, the coolant is overflowed, and the coolant is swirled while abrupt movement is restricted.

Therefore, since the discharge pipe 55a of the water tank body 55 connected to the main pump 70 is adjacent to the lower side of the fourth dilution tank 54, the first dilution tank 51 to the third dilution tank 53 The cooling water flowing down to the lower portion of the fourth dilution tank 54 is maintained at the set temperature at all times.

As a result, the cooling water that maintains the set temperature stored in the fourth dilution tank 54 is supplied to the cooling or heating load side through the discharge pipe 55b connected to the main pump 70 while the cooling water is maintained, And can be stably maintained.

According to another embodiment of the present invention, the circulation pump 80 for forcibly circulating the cooling water of the first diluting tank 51 and the third diluting tank 53 for maintaining a more precise temperature of the cooling water may be further included have.

According to the present invention, the inlet port 60 for the cooling water circulation can be located at the middle or upper end of the first dilutation tank 51 and the outlet port 61 can be located at the upper end of the third dilutation tank 53 The discharge pipe 82 of the circulation pump 80 may be connected to the input port and the suction pipe 81 of the circulation pump 80 may be connected to the output port 61 .

That is, since the cooling water is connected to the inlet 55b in the first dilution tank 51, the cooling water is kept below the set temperature, and the cooling water staying in the third dilution tank 53 flows through the second dilution tank 52 The temperature is kept close to the set temperature during the overflow.

At this time, the cooling water of the third dilution tank (53) is supplied to the first dilution tank (51) through the circulation pump (80) for circulation, so that the circulation cycle is more activated than the natural cooling water So that the set temperature of the cooling water staying in the third dilution tank 53 is controlled to rise sharply so that the temperature of the cooling water can be controlled more precisely than the method of maintaining the cooling water temperature by the natural overflow action.

And a second temperature sensor (S2) for checking the temperature of cooling water supplied to the cooling or heating load side and displaying the cooling water temperature on an external set temperature display window on the inner bottom of the fourth dilution tank (54).

The discharge pipe 55a of the fourth dilution tank 54 may be formed at a position corresponding to the through hole 59 and connected to the suction pipe 81 of the main pump 70.

According to the present invention, a cooling water passage (not shown) is formed at both lower corners of the second partition 57 and the third partition 58 so as to uniformly flow over the cooling water. Lt; / RTI >

The cooling water of the first diluting tank 51 and the cooling water of the second diluting tank 52 passes through a part of the lower cooling water toward the third diluting tank 53 on the basis of the second partition 57, The cooling water flows in correspondence with the flow of the cooling water overflowed to the upper side of the partition wall 57, thereby allowing the uniform overflow action to be smoothly performed.

A first drain port 63 for discharging cooling water and a second drain port 63 for discharging cooling water are provided under the sidewalls of the first diluting tank 51 and the fourth diluting tank 54 for cleaning and managing the inside of the water tank main body 55, (64) may be respectively formed. At this time, cooling water or washing water remaining on the bottom of the third dilution tank through the cooling water transfer passage is completely discharged through the first drain port 63 and the second drain port 64.

According to the present invention, the cooling water temperature obtained by the first temperature sensor S1 and the second temperature sensor S2 is compared with each other. Then, the supply speed of the cooling water of the main pump 70 is controlled, And a cooling water precise temperature control unit (not shown) for controlling the operation of the cooling water.

That is, according to the cooling water precise temperature control section, the cooling water temperature value supplied to the temperature lower than the set temperature in the heat exchanger 40 is compared with the cooling water temperature close to the set temperature value staying in the fourth dilution tank 54, It is possible to precisely control the set temperature of the cooling water of the fourth dilution tank 54 by selectively operating the circulation pump 80 with respect to the cooling water of the first dilution tank 51 and the third dilution tank 53.

Although not shown specifically in the drawing, temperature sensors are additionally provided in the first diluting tank 51, the second diluting tank 52 and the third diluting tank 53, respectively, so that the first temperature fine line and the second temperature The deviation of the cooling water temperature value of the sensor S2 with the cooling water temperature value of the sensor S2 is compared with the cooling water temperature value sensed in each dilution tank so that the overflowing flow rate of the cooling water is changed by changing the operating time or operating time interval of the circulation pump 80 It is needless to say that the cooling water temperature can be precisely controlled.

On the other hand, a method of accurately controlling the cooling water temperature using the overflowing multi-step dilution method of the present invention is as follows.

According to a preferred embodiment, the operation of the heat exchanger is controlled by the first temperature sensor (S1) installed in the supply pipe connected to the heat exchanger, and the temperature of the cooling water flowing from the cooling or heating load side is maintained at the set temperature, .

Next, cooling water having a temperature lower than the set temperature is supplied to the first diluting tank (51) through the inlet (55b) and stored.

Next, the cooling water of the first diluting tank (51) is retained for a predetermined time while the cooling water of the upper layer is overflowed to the second diluting tank (52) at a level lower than the highest water level of the first diluting tank (51) .

The cooling water flowing into the second dilution tank 52 is retained for a predetermined time while the cooling water in the upper layer is stored over the uppermost level stratum of the first dilution tank 51 by the third dilution tank 53 .

The cooling water flowing into the third dilution tank (53) is allowed to flow into the lower side of the fourth dilution tank (54) while staying therein for a predetermined time, and then stored.

Supplying cooling water to the cooling or heating load side through the main pump 70 connected to the lower portion of the fourth dilution tank 54 as a step for more precise control of the cooling water temperature; The cooling water of the first diluting tank 51 and the second diluting tank 52 may be forcedly circulated through the circulating pump 80.

The temperature of the cooling water of the fourth dilution tank (54) supplied to the cooling or heating load side through the second temperature sensor (S2) installed on the inner bottom of the fourth dilution tank (54) .

Although the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be defined by the appended claims and equivalents thereof.

10: compressor 20: condenser
21: receiver (receiver tank) 22: filter driver
30: expansion valve 40: heat exchanger
50: overflow type cooling water circulation member 51: first dilution tank
52: second diluting tank 53: third diluting tank
54: fourth dilution tank 55: water tank main body
56: first partition 57: second partition
58: third partition wall 59:
60: input port 61: output port
63: first drain port 64: second drain port
70: main pump 71: suction pipe
80: circulation pump 81: suction pipe
82: discharge pipe
S1: first temperature sensor S2: second temperature sensor

Claims (6)

1. A conventional cooling water temperature control system circulating a heat exchanger and a cooling or heating load region and controlling the cooling water temperature,
A first temperature sensor installed in a supply pipe connected to the heat exchanger and controlling the operation of the heat exchanger to change the cooling water to a set temperature after detecting a cooling water supply temperature flowing from the cooling or heating load side;
The cooling water is connected to the supply pipe,
A first partition and a second partition are provided on one side of the inside of the water tank body, and the upper end of the first partition is the same as the position of the inlet, and the upper end of the first partition is located at the upper end of the second partition A first diluting tank formed inside the first partition toward the inlet while being formed at a lower level;
A second diluter located outside the first partition to face the first diluter;
A third partition wall having an upper end formed to be higher than an upper end of the second partition and spaced apart from the second partition in parallel to the second partition and having a plurality of through holes extending from a central portion of the surface to a lower portion, A third diluting tank disposed at one side of the third partition wall facing the two partition walls;
A fourth diluting tank located on the other side of the third partition to face the third dilution tank; And
And a main pump connected to a lower portion of the fourth dilution tank through a discharge pipe to supply cooling water to the cooling or heating load side,
The third dilution tank and the first dilution tank are connected to the circulation pump by the suction pipe and the discharge pipe so that the cooling water of the third dilution tank and the cooling water of the first dilution tank are forcedly circulated, Or a second temperature sensor is provided to check the temperature of the cooling water supplied to the heating load side and to display it on an external set temperature display window. delete delete A method for accurately controlling cooling water temperature using a cooling water temperature precise control system according to claim 1,
Maintaining the temperature of the cooling water flowing from the cooling or heating load side at a predetermined temperature for controlling the operation of the heat exchanger by a first temperature sensor installed in a supply pipe connected to the heat exchanger and supplying the cooling water to the supply pipe;
The cooling water having a temperature lower than the set temperature is supplied to the first dilution tank through the inlet and is stored;
The cooling water of the first diluting tank is stored and stored in the second diluting tank while staying therein for a predetermined time;
Storing the cooling water flowing into the second dilution tank while being flown with the third dilution tank while staying therein for a predetermined time;
The cooling water flowing into the third dilution tank flows into the lower side of the fourth dilution tank through the through-hole located below the third dilution tank while being stored for a predetermined time, and stored;
And supplying the cooling water to the cooling or heating load side through the main pump connected to the lower portion of the fourth dilution tank. 5. The method of claim 4,
Further comprising the step of forcibly circulating the cooling water of the first diluting tank and the third diluting tank through the circulation pump. 5. The method of claim 4,
And displaying the temperature of the cooling water of the fourth dilution tank supplied to the cooling or heating load side via the second temperature sensor installed in the fourth dilution tank as an external, A Method for Precise Control of Coolant Temperature Using.

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