KR20090122890A - Constant temperature bath - Google Patents

Abstract

PURPOSE: A constant temperature bath device is provided to supply heat to a fluid within a tank through a heat pump cycle while changing a constant temperature from a low temperature zone to a high temperature zone. CONSTITUTION: A constant temperature bath device comprises a tank(60), a heater(70), and a refrigerating system. A fluid is stored in the tank. The heater and the refrigerating system control the temperature of the fluid within the tank. The refrigerating system comprises a compressor(10), an external heat exchanger(20), an expansion device(30), an internal heat exchanger(40), and a flow path changing unit. The compressor, the external heat exchanger, the expansion device and the internal heat exchanger are successively connected through a pipe line so as to circulate refrigerant. The flow path changing units are respectively connected to the compressor, the external heat exchanger and the internal heat exchanger so as to change a refrigerant path.

Description

Constant Temperature Bath

The present invention relates to a thermostat device. More specifically, the refrigeration system for maintaining the constant temperature of the fluid in the tank can be operated as a refrigeration cycle or a heat pump cycle to heat the fluid in the tank through the heat pump cycle while changing the constant temperature from the low temperature region to the high temperature region. The present invention relates to a thermostat device capable of supplying and reducing the temperature increase time for the fluid temperature in the water tank, and having low maintenance costs and high reliability.

In general, a thermostat device is widely used for maintaining a specific temperature in a laboratory and the like, and a method in which a separate temperature control device is mounted to maintain a constant temperature of the fluid stored in the tank while the fluid is stored in the tank formed of the heat insulator. It consists of.

1 is a block diagram conceptually showing a configuration of a general thermostat device according to the prior art.

As shown in FIG. 1, in a general thermostat apparatus, a fluid is stored in an inside of a water tank 60 formed of a heat insulator, and a heater 70 that exchanges heat with a fluid in the water tank 60 so as to maintain a constant temperature of the fluid. And a refrigeration system.

An inlet 61 and an outlet 62 are formed in the water tank 60 so that the fluid in the water tank 60 can be drawn in and discharged as needed, and the fluid in the water tank 60 has an entire space inside the water tank 60. In the stirrer 80 is mixed with the fluid to be maintained at a uniform temperature is mounted. The stirrer 80 is configured in the form of a rotary blade 82 driven by the drive motor 81. In addition, the heater 70 is configured to dissipate heat in the water tank 60 and is configured to supply heat to the fluid in the water tank 60, wherein the refrigeration system is a refrigerant endothermic reaction and heat from the fluid in the water tank 60. It is configured to absorb. That is, the refrigeration system is composed of a compressor 10, a condenser 20, an expansion device 30 and an evaporator 40 to form one refrigeration cycle, the main piping line (L) to the refrigerant to circulate in each device Is sequentially connected through, the condenser 20 is disposed outside the water tank 60 to heat exchange with the outside, the evaporator 40 is arranged inside the water tank 60 is configured to heat exchange with the fluid in the water tank 60 .

Therefore, the fluid in the water tank 60 exchanges heat with the evaporator 40 of the refrigerating system and loses heat and at the same time receives heat through the heater 70 to compensate for this, thereby maintaining a constant temperature continuously.

Such a thermostat device according to the related art can generally set various settings for the constant temperature of the fluid stored in the water tank 60 to a range such as a low temperature region or a high temperature region. When changing to a high temperature region, for example, when changing the constant temperature from -20 ° C to 30 ° C, in order to raise the fluid temperature in the water tank 60, only the heater 70 needs to be operated to provide heat. There was a problem that took a long time. In addition, when the capacity of the heater 70 is increased to shorten the temperature raising time, a problem of overloading of the heater 70 occurs, and when the capacity of the water tank 60 is reduced, a problem of decreasing the constant temperature capability occurs. do. In particular, in the case of an electric heater, a problem such as disconnection of the heater 70 occurs when a load of the heater 70 is applied from the initial stage to the rated temperature in order to shorten the temperature raising time, which causes difficulty in maintenance.

Therefore, the present invention is invented to solve the problems of the prior art, it is configured to operate the refrigeration system for maintaining the constant temperature of the fluid in the tank as a refrigeration cycle or a heat pump cycle to change the constant temperature from the low temperature region to the high temperature region In the meantime, the object of the present invention is to provide heat to the fluid in the tank through the heat pump cycle, thereby shortening the temperature increase time for the fluid temperature in the tank, and providing a low-cost maintenance cost and a reliable thermostat device.

The present invention, the fluid tank is stored; And a heater and a refrigeration system for controlling the temperature of the fluid in the water tank, wherein the refrigeration system comprises: a compressor, an external heat exchanger, an expansion device, and an internal heat exchanger, which are sequentially connected through a pipe line to circulate the refrigerant; And a flow path changing means connected to the compressor, an external heat exchanger, and an internal heat exchanger, respectively, to change refrigerant flow paths between the compressor, an external heat exchanger, and an internal heat exchanger. It provides a thermostat device characterized in that the heat exchange with the fluid in the tank through an internal heat exchanger.

In this case, the flow path changing means may include a four-way valve formed with four valve terminals.

In addition, the four-way valve is formed with first, second, third and fourth valve terminals, and the first and third valve terminals are respectively connected to the internal heat exchanger and the external heat exchanger, respectively. Four valve terminals are respectively connected to the outlet port and the inlet port of the compressor, and when the refrigeration system operates in a refrigeration cycle, the second valve terminal is the third valve terminal, and the first valve terminal is the first valve. Respectively communicating with four valve terminals, wherein the first valve terminal is configured to communicate with the second valve terminal, and the third valve terminal is configured to communicate with the fourth valve terminal, respectively, when the refrigeration system operates in a heat pump cycle. Can be.

In addition, the thermostat device comprises a temperature switch for setting the fluid temperature in the tank; A temperature sensor for measuring a fluid temperature in the tank; And a controller for controlling the operation of the heater and the refrigeration system, wherein the controller compares the set temperature set by the temperature switch with the measured temperature measured by the temperature sensor, so that the set temperature is greater than or equal to the measured temperature. If it is set high, the flow path changing means may be adjusted to control the refrigeration system to operate in a heat pump cycle.

In addition, the expansion device may be an electronic expansion valve that can adjust the flow rate of the refrigerant in accordance with the degree of superheat of the refrigerant, the electronic expansion valve may be controlled by the control unit.

According to the present invention, by configuring the refrigeration system for maintaining the constant temperature of the fluid in the tank to operate as a refrigeration cycle or a heat pump cycle, the fluid in the tank through the heat pump cycle during the change of the constant temperature from the low temperature region to the high temperature region There is an effect that can supply heat to shorten the temperature increase time for the fluid temperature in the tank accordingly.

In addition, since it is possible to shorten the temperature increase time of the constant temperature through the refrigeration system, it is not necessary to provide a separate heat source when changing the temperature increase of the constant temperature, and it is not necessary to change the capacity of the heater and the capacity of the water tank, so that maintenance is easily performed. It works.

In addition, by using an electronic expansion valve that can adjust the amount of refrigerant in accordance with the degree of refrigerant superheat, it is possible to ensure the superheat of the refrigerant at the inlet side of the compressor even when operating in the heat pump cycle, thereby improving the reliability of the refrigeration system It is effective.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

Figure 2 is a block diagram conceptually showing the configuration of a thermostat device according to an embodiment of the present invention, Figure 3 is a pressure-enthalpy diagram for the refrigeration system of the thermostat device according to an embodiment of the present invention.

The thermostat device according to an embodiment of the present invention includes a water tank 60 in which the fluid is stored, a heater 70 and a refrigeration system for controlling the temperature of the fluid in the water tank 60.

The water tank 60 is preferably formed of a heat insulating material to prevent the fluid stored therein from being heat-exchanged with the outside and to maintain the constant temperature of the fluid more smoothly, and one side of the water tank 60, as necessary, the water tank 60 Inlet 61 and outlet 62 are formed to allow the fluid inside and out).

The heater 70 is disposed inside the water tank 60 to supply heat to the fluid stored in the water tank 60 and adjust the temperature of the fluid, and the refrigerating system exchanges heat with the fluid stored in the water tank 60 through the internal circulation of the refrigerant. And arranged to regulate the temperature of the fluid. In addition, in the water tank 60, a stirrer 80 for mixing the fluid is arranged so that the fluid temperature controlled by the heater 70 and the refrigeration system can exhibit a uniform temperature distribution in the entire space in the water tank 60. The stirrer 80 includes a rotary blade 82 disposed and rotated in the water tank 60 to generate a fluid flow as shown in FIG. 2, and a drive motor 81 for rotationally driving the rotary blade 82. It is configured by. Therefore, the fluid in the water tank 60 is evenly mixed in the water tank 60 through this stirrer 80 to have a uniform temperature distribution in the entire space. In this case, the heater 70 and the stirrer 80 disposed in the water tank 60 are preferably operated to automatically maintain a constant temperature of the fluid through a control signal applied from the controller 50 to be described later. Accordingly, the drive motor 81 of the heater 70 and the stirrer 80 is preferably configured of an electric heater and an electric motor method that operate by electric signals.

The refrigeration system is configured such that the compressor 10, the external heat exchanger 20, the expansion device 30, and the internal heat exchanger 40, which are sequentially connected through the pipe line L, form a refrigeration cycle so that the refrigerant is circulated. In addition, according to an embodiment of the present invention is connected to the compressor 10, the external heat exchanger 20 and the internal heat exchanger 40 is configured to include a flow path changing means for changing the refrigerant flow path between each other.

The compressor 10, the external heat exchanger 20, the expansion device 30 and the internal heat exchanger 40 operate in a general refrigeration cycle, with the external heat exchanger 20 acting as a condenser and the internal heat exchanger 40 acting as an evaporator. The internal heat exchanger 40 is disposed inside the water tank 60 to exchange heat with the fluid in the water tank 60, and the external heat exchanger 20 is arranged outside the water tank 60 to heat exchange with the outside air. . Each of these components is sequentially connected through a pipe line (L) so that the refrigerant is circulated, the low-temperature low-pressure gas phase refrigerant passing through the internal heat exchanger 40 that operates as an evaporator is a high-temperature, high-pressure gas phase through the compressor (10) It is compressed into a refrigerant, and condensed into a liquid refrigerant of high temperature and high pressure through an external heat exchanger 20 that operates as a condenser, and expands into a liquid refrigerant of low temperature and low pressure through an expansion device 30, and then internally heat exchanger 40. It is configured to circulate the process of evaporating through the low-temperature low-pressure gas phase refrigerant.

As such, the compressor 10, the external heat exchanger 20, the expansion device 30, and the internal heat exchanger 40 configured as a refrigeration cycle are connected to each other through the flow path changing means described above according to an embodiment of the present invention. The circular path is changed. That is, the flow path changing means is connected to the compressor 10, the external heat exchanger 20 and the internal heat exchanger 40, respectively, and the circulation path of the refrigerant is the compressor 10, the internal heat exchanger 40, and the expansion device 30. ) And the flow path of the coolant so as to proceed to the external heat exchanger 20, and thus the circulation path of the coolant represents a circulation path opposite to the above-mentioned refrigeration cycle and forms a heat pump cycle. Therefore, in this heat pump cycle, the internal heat exchanger 40 operates as a condenser and the external heat exchanger 20 operates as an evaporator.

Therefore, the thermostat device according to an embodiment of the present invention operates to achieve a refrigerant cycle or a heat pump cycle, and thus the internal heat exchanger 40 disposed inside the water tank 60 operates as an evaporator or a condenser. When the internal heat exchanger 40 operates as an evaporator, since the refrigerant evaporates through the internal heat exchanger 40 and takes heat from the fluid in the water tank 60, the fluid temperature inside the water tank 60 is lowered, When the internal heat exchanger 40 operates as a condenser, since the refrigerant condenses through the internal heat exchanger 40 and provides heat to the fluid in the water tank 60, the fluid temperature inside the water tank 60 is increased. .

According to this structure, the thermostat device according to an embodiment of the present invention generally operates in a refrigerating state, as described above, the refrigeration system operates in a refrigerating cycle to remove heat from the fluid in the water tank 60. Heat compensation 70 is configured to operate to provide heat to the fluid to maintain the constant temperature of the fluid. On the contrary, when the constant temperature setting of the fluid is changed from the low temperature region to the high temperature region, the refrigeration system operates in a heat pump cycle to provide heat to the fluid in the water tank 60 so that the fluid temperature in the water tank 60 is increased. It is composed.

Therefore, the thermostat device according to an embodiment of the present invention is an internal heat exchanger that forms a heat pump cycle in addition to providing heat by the operation of the heater 70 when changing the temperature setting of the fluid from a low temperature region to a high temperature region ( Since heat is supplied to the fluid in the water tank 60 through 40, the temperature rise time for the fluid is significantly shortened. Therefore, it is not necessary to supply a separate heat source in order to shorten the temperature increase time, and it is not necessary to change the capacity of the heater or the capacity of the water tank, so that it is possible to change the stable temperature rise for the constant temperature.

On the other hand, the flow path changing means according to an embodiment of the present invention is a four-way valve 90 is formed with four valve terminals (91, 92, 93, 94) that can be selectively changed so as to communicate with each other two by two as shown in FIG. It may be configured to include).

In more detail, the four-way valve 90 has first, second, third, and fourth valve terminals 91, 92, 93, and 94, and the first and third valve terminals 91, 93 are formed. Respectively, the internal heat exchanger 40 and the external heat exchanger 20 are respectively connected, and the second and fourth valve terminals 92 and 94 are respectively connected to the outlet port and the inlet port of the compressor 10, respectively.

At this time, when the refrigeration system operates in a refrigeration cycle, the four-way valve 90 has a second valve terminal 92 in communication with the third valve terminal 93 as shown in FIG. The internal flow path is changed so that the one valve terminal 91 communicates with the fourth valve terminal 94. Therefore, in this case, the circulation path of the refrigerant proceeds in the order of the compressor 10, the external heat exchanger 20, the expansion device 30, and the internal heat exchanger 40. On the other hand, when the refrigeration system operates in a heat pump cycle, the four-way valve 90 has a first valve terminal 91 in communication with the second valve terminal 92 as shown in FIG. The internal flow path is changed so that the three valve terminal 93 communicates with the fourth valve terminal 94. Therefore, in this case, the circulation path of the refrigerant proceeds in the order of the compressor 10, the internal heat exchanger 40, the expansion device 30, and the external heat exchanger 20.

On the other hand, the thermostat according to an embodiment of the present invention is a temperature switch 64, which can be operated by the user to set the temperature of the fluid stored in the tank 60, as shown in Figure 2, and in the tank 60 It further comprises a temperature sensor 65 for measuring the temperature of the stored fluid, and also, as described above, the controller 50 for controlling the operation of the heater 70 and the stirrer 80 is provided, and such a controller ( 50 is configured to receive a signal for the set temperature and the measured temperature from the temperature switch 64 and the temperature sensor 65 to control the operation of the refrigeration system.

In more detail, when the user sets the constant temperature of the fluid in the water tank 60 through the temperature switch 64, the control unit 50 controls the set temperature and the temperature sensor 65 set by the temperature switch 64. When the set temperature is set higher than the measured temperature by comparing the measured temperature measured by the measured temperature, the flow path changing means is adjusted to control the refrigeration system to operate in a heat pump cycle. At this time, the reference temperature difference may be variously set to a preset value according to the user's needs or the operating characteristics of the refrigeration system.

In other words, when the user sets the constant temperature of the fluid to a high temperature region that is higher than the current temperature by a temperature switch 64, the refrigeration system performs a heat pump cycle while the temperature of the fluid is elevated to the high temperature region. It is controlled by the controller 50, in the case of the four-way valve 90 described above, the first and second valve terminals 91 and 92 communicate with each other and the third and fourth valve terminals 93 and 94 communicate with each other. Controlled. Thus, the internal heat exchanger 40 operates as a condenser, causing the temperature of the fluid in the water tank 60 to rise. When the temperature of the fluid rises to the set temperature through this process, the controller 50 again controls the flow path changing means to control the refrigeration system to achieve a refrigeration cycle, and through this the fluid temperature in the water tank 60 is a temperature switch ( It will be kept constant at the set temperature set through 64).

Accordingly, the thermostat device according to an embodiment of the present invention is not only supplied heat to the fluid in the water tank 60 by the operation of the heater 70 while the constant temperature of the fluid is changed from the low temperature region to the high temperature region, as well as the refrigeration system. Since heat is also supplied by the internal heat exchanger 40 operating as a condenser by making this heat pump cycle, the temperature increase time is significantly shortened when the temperature is changed with respect to the constant temperature of the fluid.

Meanwhile, in the expansion device 30 according to the exemplary embodiment, the refrigerant flows in both directions of the expansion device 30 even when the refrigerant flow is changed by the four-way valve 90, and at the same time, the refrigerant increases according to the superheat degree of the refrigerant. It is preferable to apply an electronic expansion valve that can adjust the flow rate of the electronic expansion valve, it is preferable that the operation is controlled by the controller 50.

That is, the refrigeration system according to an embodiment of the present invention operates in a refrigeration cycle and a heat pump cycle, in the case of the refrigeration cycle as shown in the cycle of 1-2-3-4-1 shown in FIG. The superheat can be secured at the low pressure stage of the side (coordinate 1 point) to ensure the reliability of the compressor. However, in the case of the heat pump cycle, the 1 'shown in FIG. As in the cycle of -2'-3'-4'-1 ', the temperature at the compressor inlet side (point 1') is increased and the pressure at the compressor inlet low pressure stage is increased, making it difficult to secure overheating. As such, if it is difficult to secure overheating at the compressor inlet, liquid refrigerant flows into the compressor 10, thereby damaging the compressor 10 and deteriorating reliability of the system. Therefore, the expansion device 30 according to the embodiment of the present invention has a variable area expansion that can adjust the flow rate of the refrigerant through the opening amount control to secure the superheat degree of the refrigerant at the low pressure end of the compressor 10. An electronic expansion valve is applied. The electronic expansion valve is preferably controlled by the control unit 50, and adjusts the opening amount of the electronic expansion valve according to the superheat degree of the refrigerant, and thus a'-2'-3'-4'-a shown in FIG. Configured to achieve a cycle of '. For example, when it is difficult to secure the superheat of the refrigerant, it may be controlled by reducing the amount of opening of the electronic expansion valve.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

1 is a block diagram conceptually showing a configuration of a general thermostat device according to the prior art;

2 is a block diagram conceptually showing a configuration of a thermostat device according to an embodiment of the present invention;

3 is a pressure-enthalpy diagram for a refrigeration system of a thermostat device in accordance with one embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: compressor 20: condenser

30: expansion device 40: evaporator

50: control unit 60: water tank

70: heater 80: stirrer

90: four-way valve

Claims (5)

A tank in which the fluid is stored; And Heater and refrigeration system to control the temperature of the fluid in the tank Including, the refrigeration system A compressor, an external heat exchanger, an expansion device, and an internal heat exchanger, which are sequentially connected through a pipe line to circulate the refrigerant; Flow passage changing means connected to the compressor, an external heat exchanger, and an internal heat exchanger, respectively, to change refrigerant passages therebetween; And a cooling cycle or a heat pump cycle according to the change of the refrigerant flow path by the flow path changing means, and the heat exchanger device exchanges heat with the fluid in the water tank through the internal heat exchanger. The method of claim 1, And said flow path changing means comprises a four-way valve on which four valve terminals are formed. The method of claim 2, First, second, third, and fourth valve terminals are formed in the four-way valve, and the first and third valve terminals are respectively connected to the internal heat exchanger and the external heat exchanger, respectively, and the second and fourth valves are provided. Terminals are respectively connected to the outlet port and the inlet port of the compressor, and when the refrigeration system operates in a refrigeration cycle, the second valve terminal is the third valve terminal, and the first valve terminal is the fourth valve. And the first valve terminal communicates with the second valve terminal, and the third valve terminal communicates with the fourth valve terminal, respectively, when the refrigeration system operates in a heat pump cycle. Thermostat device. The method according to any one of claims 1 to 3, A temperature switch for setting a fluid temperature in the tank; A temperature sensor for measuring a fluid temperature in the tank; And Control unit for controlling the operation of the heater and the refrigeration system The control unit may further include comparing the set temperature set by the temperature switch with the measured temperature measured by the temperature sensor, and adjusting the flow path changing means when the set temperature is set to be higher than a reference temperature difference. A thermostat device characterized in that the system is controlled to operate in a heat pump cycle. The method of claim 4, wherein The expansion device is a thermostat device characterized in that the electronic expansion valve is applied to adjust the flow rate of the refrigerant in accordance with the superheat degree of the refrigerant, the electronic expansion valve is controlled by the control unit.

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