JPH0746012B2 - Cold temperature controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention uses a cold-controlled brine (water or liquid) for a load of a plastic molding die or the like arranged at a position distant from an apparatus main body. The present invention relates to a cooling and temperature adjusting device used to maintain a predetermined temperature.

(B) Conventional Technology The applicant has previously proposed, as this type of cooling and controlling apparatus, one shown in FIG. 5 (Japanese Patent Application No. 62-293239).

In FIG. 5, (A) comprises a compressor (1), a condenser (2), a dryer (3), a capillary tube (4), an evaporator (5) and an accumulator (6), which are sequentially connected in an annular shape. The refrigerant circuit, (B), is a brine circulation path that circulates the brine in the liquid tank (7) to the load (9) such as a mold via the circulation pump (8). The liquid tank (7) is made of stainless steel with an open upper part, and the inside of the tank is divided into an upper brine chamber (7a) and a lower brine chamber (7b) by a partition plate (11) having a liquid passage hole (10). Has been done. The evaporator (5) is immersed in the brine in the upper brine chamber (7a), and the heater (12) is inserted in the lower brine chamber (7b). The brine circulation path (B) has a forward flow path (13) and a return flow path (14) between the load (9) and the liquid tank (7), and the return flow path (14) is the liquid tank (7). ) 2 branch roads (14a) (1
It is branched to 4b). And one branch road (14a)
Is connected to the upper brine chamber (7a) and the other branch (14a
b) is connected to the lower brine chamber (7b). Also,
By making the pipe diameter of the branch passage (14b) larger than the pipe diameter of the branch passage (14a) and providing the resistor (15) in the branch passage (14b), the upper brine chamber (7a) and the lower brine chamber (7a) The amount of brine flowing into (7b) is adjusted appropriately.
Further, the inlet (16a) and the first outlet (16b) of the three-way switching valve (16) are connected to the return flow passage (14) upstream of these branch passages (14a) (14b), and the three-way An air-cooling heat exchanger flow path (19) having an air-cooling heat exchanger (18) is connected between the second inlet (16c) of the switching valve (16) and both branch passages (14a) (14b). Has been done. Further, (20) is a bypass pipe that is connected in parallel with the air-cooling type heat exchanger (18) and has a resistor (21), (23) is a fan, (24) is a control device, and the fan (23). A condenser (2) and an air-cooling type heat exchanger (18) are juxtaposed in the air passage of.

The control device (24) has a temperature sensor (25) for detecting the brine temperature of the return flow path (14) and a room temperature sensor (26),
The compressor (1), the circulation pump (8), the heater (12), the three-way switching valve (16) and the fan (23) are controlled.

In the conventional device described above, when the brine temperature is maintained at a predetermined temperature from 15 ° C to 50 ° C, the control device (24) operates the compressor (1), the circulation pump (8) and the fan (23), and Switch the switching valve (16) as shown by arrow a. Further, the ON / OFF energization time of the heater (12) is linearly controlled according to the temperature detected by the temperature sensor (25). Therefore, the brine cooled in the upper brine chamber (7a) and the brine heated in the lower brine chamber (7b) merge in the lower brine chamber (7b) to become brine having a predetermined temperature, and the forward flow path (13) To the load (9) via. Further, the brine of the load (9) is returned to the return passage (14) and the branch passage (14).
Return to the upper brine chamber (7a) and the lower brine chamber (7b) via a) (14b). In this way, the brine in the liquid tank (7) is circulated and supplied to the load (9), and the load temperature is maintained near a predetermined temperature (15 to 50 ° C).

When maintaining the brine temperature at a predetermined temperature from 50 ° C to 90 ° C, the control device (24) stops the compressor (1), operates the circulation pump (8) and the fan (23), and operates the three-way switching valve ( Change 16) as shown by arrow B. In addition, the heater (12) is turned on according to the temperature detected by the temperature sensor (25),
Linearly controls the turn-off time. Furthermore, the rotation speed of the fan (23) is controlled according to the temperature difference between the temperature sensor (25) and the room temperature sensor (26), and the rotation speed of the fan (23) is reduced when the temperature difference is large. At the same time, when the temperature difference is small, the rotation speed of the fan (23) is increased. Therefore, the brine flowing out of the liquid tank (7) has an outflow passage (13) -load (9) -three-way switching valve (16) -air cooling heat exchanger passage (19) and bypass pipe (20) -branch. Road (14a)
The temperature of the brine supplied to the load (9) by flowing in the order of (14b) and returning to the liquid tank (7) depends on the heat radiation amount of the air-cooling type heat exchanger (18) and the heating amount of the heater (12). Maintained at a predetermined temperature (50-90 ° C).

(C) Problem to be Solved by the Invention In the above-described conventional apparatus, when the brine temperature is set to 40 ° C. or higher, the degree of superheat of the suction gas of the refrigerant compressor becomes excessive,
There was a danger that the compressor would stop due to the temperature rise of the high pressure gas and the temperature rise of the motor winding. Further, if the temperature is set to 50 ° C. or higher, the compressor cannot be operated, so the brine temperature must be adjusted by the heating amount of the heater and the heat radiation amount of the air-cooling type heat exchanger.

This invention has been made in view of the above facts,
Expand the operable range of the refrigeration cycle for the brine set temperature so that stable cooling and temperature control operation can be performed by cooling with the evaporator and heating of the heater even when the brine temperature is set to a high temperature range exceeding 50 ° C, for example. The purpose is to do.

(D) Means for Solving the Problems In the present invention, a refrigerant circuit in which a compressor, a condenser, a decompression device, and an evaporator are connected, a liquid tank in which the evaporator is immersed in brine, a circulation pump, and In the one having a heater and a brine circulation path for circulating brine to a load, an intake gas cooler for exchanging heat with this circuit portion is provided in a refrigerant circuit between an evaporator and a compressor, and a condenser is provided. A refrigerant circuit between the evaporator and the evaporator is branched into a first branch passage having a first pressure reducing device and the suction gas cooler and a second branch passage having a second pressure reducing device, and a refrigerant switching device is provided in both branch passages. Is provided.

Further, in the present invention, a refrigerant circuit in which a compressor, a condenser, a pressure reducing device and an evaporator are connected, a liquid tank in which the evaporator is immersed in brine, a circulation pump and a heater are provided, and the brine is loaded. A brine circuit that circulates in the refrigerant circuit, a refrigerant circuit between the evaporator and the compressor is provided with an intake gas cooler that exchanges heat with this circuit unit, and a refrigerant circuit between the pressure reducing device and the evaporator is provided. A first branch path having the suction gas cooler is branched into a second branch path that bypasses the first branch path, and a refrigerant switching device is provided in both branch paths.

(E) Operation When the brine temperature is set low, the refrigerant decompressed by the decompressor is directly passed to the evaporator to maximize the cooling capacity of the evaporator. Also, when the brine temperature is set to a high value, the refrigerant decompressed by the decompression device is made to flow through the intake gas cooler to the evaporator, and the refrigerant that is overheated at the evaporator is cooled before being sucked into the compressor. Let This way,
The operable range of the refrigeration cycle is expanded in the temperature range,
Stable cold temperature control operation becomes possible.

(F) Embodiment Hereinafter, an embodiment of the present invention shown in the drawings will be described.

In FIG. 1, the same parts as those in FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, an evaporator (5) comprises three coils, a first evaporator (5a), a second evaporator (5b) and a third evaporator (5).
c) is divided into and these are sequentially connected in series. The first evaporator (5a) and the third evaporator (5c) are housed vertically in the upper brine chamber (7a), and the second evaporator (5b) is housed in the lower brine chamber (7b). The refrigerant circuit (C) between the evaporator (5) and the compressor (1) is provided with an intake gas cooler (27) having a double pipe structure for exchanging heat with the pipe of this circuit section. Further, in the refrigerant circuit (D) between the condenser (2) and the evaporator (5), a refrigerant on-off valve (28) as a refrigerant switching device, a first pressure reducing device (29) including a capillary tube, and suction gas. A first branch passage (30) having a cooler (27), a refrigerant opening / closing valve (31) as a refrigerant switching device, and a second branch passage (33) having a second pressure reducing device (32) formed of a capillary tube. Has been branched into. A first flow path (35) having a first opening / closing valve (34) in the forward flow path (13) between the circulation pump (8) and the load (9).
And a second flow path (37) whose flow path resistance is adjusted by a throttle device (36) such as a resistor, a third flow path having a second on-off valve (38) and an air-cooling heat exchanger (18) A parallel flow path consisting of (40) is inserted. The heater (12) is inserted in the heating tank (41) inserted in the return flow path (14). Further, the brine in the return flow path (14) flows into the upper brine chamber (7a) and the lower brine chamber (7b) after being branched by the box-shaped header (42) attached to the side surface of the liquid tank (7). To do.

In the apparatus of the above-described embodiment, when the brine temperature is maintained at a predetermined temperature of 15 ° C to 60 ° C, the controller (24) operates the compressor (1), the circulation pump (8) and the fan (23), and ON / OFF energization time of the heater (12) is linearly controlled according to the temperature detected by the sensor (25) to adjust the brine temperature to a predetermined temperature. Further, the first opening / closing valve (34) of the brine circulation path (B) is opened and the second opening / closing valve (38) is opened. At this time, in the brine circulation path (B), brine is stored in the liquid tank (7) -circulation pump (8) -first flow path (35) and second flow path (37) -load (9) -heating tank (41). -Header- (42) -The liquid tank (7) flows in this order, and the temperature of the load (9) is maintained near a predetermined temperature by the cooling amount by the evaporator (5) and the heating amount of the heater (12). .

On the other hand, in the refrigerant circuit (A), the following refrigerant flow is performed depending on whether the brine temperature is adjusted to a predetermined temperature in the low temperature range of 15 to 40 ° C or the intermediate temperature range of 40 to 60 ° C. Control is performed. That is, in the above-mentioned low temperature range, the refrigerant on-off valve (31)
And the refrigerant on-off valve (28) are closed, and the refrigerant passing through the dryer (3) is decompressed by the decompression device (32) of the second branch path (33) and then supplied to the evaporator (5). Then, the cooling capacity of the evaporator (5) is maximized. In the above-mentioned medium temperature range, the refrigerant on-off valve (28) is opened, the refrigerant on-off valve (31) is closed, and the refrigerant passing through the dryer (3) is passed through the first branch passage (30) to the evaporator. Supply to (5). Therefore, the gas-liquid refrigerant decompressed by the decompression device (29) and the refrigerant of the evaporator (5) which has become superheated vapor by heat exchange with the brine are heat-exchanged in the intake gas cooler (27). The refrigerant drawn into the compressor (1) is kept in superheated steam at an appropriate temperature. As a result, the brine temperature is 40 ~
Even under the condition of being kept at a high temperature of 60 ° C, the refrigeration cycle operation by the refrigerant circuit (A) can be performed without any trouble.

Next, the case where the brine temperature is maintained at a predetermined temperature of 60 ° C. to 90 ° C. will be described. Since the refrigeration cycle operation becomes difficult under such conditions, the control device (24) stops the compressor (1), operates the circulation pump (8) and the fan (23), and operates the temperature sensor (25). The ON / OFF energization time of the heater (12) is linearly controlled according to the detected temperature. Further, the first opening / closing valve (34) is closed and the second opening / closing valve (38) is opened. Furthermore, the temperature difference between the brine temperature and the room temperature sensor (26) is detected, and when the temperature difference is large (when the brine temperature is adjusted to a high value), the rotation speed of the fan (23) is reduced to reduce the temperature difference. When is small (when the brine temperature is adjusted to a low level), increase the rotation speed of the fan (23). Therefore, the brine is stored in the liquid tank (7) -circulation pump (8) -second channel (37) and third channel (40) -load (9) -heating tank (41) -liquid tank (7). The temperature of the brine that flows in sequence and is supplied to the load (9) is maintained at a predetermined temperature by the amount of heat released by the air-cooling heat exchanger (18) and the amount of heating by the heater (12).

According to the present embodiment, when the brine temperature is adjusted by the refrigerant amount of the evaporator (5) immersed in the liquid tank (7) and the heating amount of the heater (12), the brine temperature is low (15-).
When the temperature is 40 ° C, the refrigerant decompressed in the second branch passage (33) is directly flown into the evaporator (5), and the brine temperature is higher (40 to 60).
(° C), the refrigerant is depressurized in the first branch passage (30), and the suction gas cooler (27) further exchanges heat with the suction gas of the compressor (1) before flowing to the evaporator (5). Because I did, the third
As shown in the figure, it is possible to lower the temperature of the suction gas of the compressor (1) in the high temperature range while sufficiently securing the cooling capacity in the low temperature range. Refrigeration cycle operation is possible even at temperature.

FIG. 4 shows another embodiment of the present invention. In this embodiment, a common pressure reducing device (43) is used instead of providing a pressure reducing device in each branch path.
A first branch passage (30) having an on-off valve (28) and an intake gas cooler (27) between the evaporator (5) and the on-off valve (3)
The second branch path (33) having 1) is provided in parallel.

(G) Effect of the Invention Since the present invention is configured as described above, the operable range of the refrigeration cycle with respect to the brine set temperature is significantly expanded in the high temperature range (for example, 40 to 60 ° C), and the low temperature range ( For example, it is possible to secure sufficient cooling capacity at 15 to 40 ° C, and it has been impossible to achieve high temperatures in the past (for example, 50 to 40 ° C).
The brine temperature of 60 ℃) can be adjusted by cooling with an evaporator and heating with a heater, and stable cooling and temperature control operation can be expected over a wide range.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a cooling and temperature controlling apparatus showing an embodiment of the present invention, FIG. 2 is a front view of a liquid tank, FIG. 3 is an explanatory view of operating characteristics of the cooling and temperature controlling apparatus, and FIG. FIG. 5 is a schematic configuration diagram of a cold / temperature control device showing another embodiment, and FIG. 5 is a schematic configuration diagram of a conventional cool / temperature control device. (A) ... Refrigerant circuit, (1) ... Compressor, (2) ... Condenser, (5) ... Evaporator, (B) ... Brine circuit,
(7) …… Liquid tank, (8) …… Circulation pump, (27)
...... Suction gas cooler, (28) (31) …… Refrigerant on-off valve (refrigerant switching device), (29) (32) (43) …… Pressure reduction device, (3
0) ... first branch, (33) ... second branch.

Claims (2)

[Claims] 1. A refrigerant circuit A formed by connecting a compressor 1, a condenser 2, decompression devices 29 and 32, and an evaporator 5, a liquid tank 7 in which the evaporator 5 is immersed in brine, and a circulation pump 8. And a heater 12 and a brine circulation path B for circulating brine to a load, the evaporator 5 and the compressor 1
An intake gas cooler 27 for exchanging heat with this circuit portion is provided in the refrigerant circuit C between the first and second decompression devices 29 and the intake gas cooler 27 between the condenser circuit 2 and the evaporator 5. And a second branch passage 33 having the second pressure reducing device 32, and refrigerant switching devices 28 and 31 are provided on both of the branch passages. 2. A refrigerant circuit A formed by connecting a compressor 1, a condenser 2, decompression devices 29 and 32, and an evaporator 5, a liquid tank 7 in which the evaporator 5 is immersed in brine, and a circulation pump 8. And a heater 12 and a brine circulation path B for circulating brine to a load, the evaporator 5 and the compressor 1
The refrigerant circuit C between the inlet and outlet is provided with a suction gas cooler 27 that exchanges heat with this circuit portion, and the refrigerant circuit between the pressure reducing device 43 and the evaporator 5 is provided with the suction gas cooler 27. And a second branch path 32 that bypasses the first branch path 30, and refrigerant switching devices 28 and 31 are provided on both branch paths.