JP2010096394A - Liquid temperature control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce running cost and make liquid promptly reach target temperature while saving energy. <P>SOLUTION: This liquid temperature control device 30 includes a control device 60 for heating and controlling liquid within a tank 31 to achieve target temperature. When the target temperature is less than a preset first threshold value and a temperature difference between the target temperature and liquid temperature before temperature control is less than a preset second threshold value, the control device 60 determines the low liquid temperature excessive small load state. When the target temperature is less than the preset first threshold value and the temperature difference between the target temperature and the liquid temperature before temperature control is the second threshold value or more, the control device 60 determines the low liquid temperature high load state. When the target temperature is the preset first threshold value or more, the control device 60 determines the high liquid temperature state. The control device 60 executes control methods different among the low liquid temperature excessive small load state, the low liquid temperature high load state and the high liquid temperature state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid temperature adjusting device that heats a liquid to a predetermined temperature.

As a device for adjusting the temperature of the liquid stored in the tank, one having a configuration as shown in FIG. 5 is known.
In this temperature adjusting device 10, a cooling serpentine tube 11 through which cooling water flows and an electric heater 12 are arranged in a container 13 in which liquid is stored, and the liquid temperature is adjusted by the cooling serpentine tube 11 and the electric heater 12. A configuration is disclosed (for example, see Patent Document 1).
Further, in the temperature adjusting device 10, a stirring device 15 is provided in order to eliminate unevenness in the liquid temperature.

  In addition, a configuration in which a heater for heating is wound around the outer periphery of a tank in which liquid is stored (or distributed) to heat the liquid is also conventionally known (see, for example, Patent Document 2).

JP 2001-82885 A Japanese Patent Laid-Open No. 9-289076

  As described above, in the conventional liquid temperature adjusting device, a heater such as an electric heater is disposed inside the tank or outside the tank and is heated by the heater. For this reason, in the conventional liquid temperature control apparatus, the amount of power consumption becomes enormous, the running cost increases, and there is a problem that heating by the heater is wasteful energy consumption from the viewpoint of energy saving.

  In particular, when the liquid temperature is to be adjusted rapidly, heater heating requires a very large amount of power, and when a normal power source is used, it takes a relatively long time to reach the target temperature. .

  Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to adjust the liquid temperature so that the running cost can be reduced and the liquid can be quickly brought to the target temperature while saving energy. To provide an apparatus.

According to the liquid temperature adjusting device of the present invention, in the liquid temperature adjusting device provided with the control device for controlling the liquid in the tank to be heated to the target temperature, the compressor and the heat medium for compressing the heat medium A temperature adjusting circuit in which a condenser for condensing the liquid into a liquid, an expander for lowering the heat medium and an evaporator for vaporizing the heat medium are connected by a flow pipe through which the heat medium flows, and the temperature adjustment A four-way valve for reversing the flow direction of the heat medium in the circuit, and a part of the flow pipe is attached to the outer wall surface of the tank or disposed inside the tank, and the condenser or evaporator of the temperature adjustment circuit The tank is heated to cool or cool the liquid in the tank, and when the tank is heated, the evaporator is provided so as to absorb heat from an external heat source. A regulating circuit is provided so as to constitute a heat pump circuit, a liquid temperature sensor for measuring a liquid temperature in the tank is provided, and the control device is configured such that the target temperature is lower than a preset first threshold value. When the temperature difference between the target temperature and the liquid temperature before temperature adjustment is less than a preset second threshold, it is determined that the liquid temperature is under an overload state, and the target temperature is set in advance. If the temperature difference between the target temperature and the liquid temperature before temperature adjustment is greater than or equal to a preset second threshold value, it is determined that the low liquid temperature / high load state is present. When the target temperature is equal to or higher than a preset first threshold value, it is determined that the liquid temperature state is high, and the low liquid temperature overload state and the low liquid temperature high load state are used. It is characterized in that different control methods are executed in the high liquid temperature state. There.
According to this structure, since it heats with a heat pump without using a heater and makes it reach | attain target temperature, rapid heating is possible and energy saving can be aimed at at the time of a heating. In addition, according to this configuration, it is possible to control using the cooling operation in spite of the heating control by switching the four-way valve by the temperature adjustment circuit instead of the control by the heater on / off as in the conventional case. .

Further, in the case of a low liquid temperature underload condition, the control device rapidly heats the liquid in the tank by setting the compressor of the temperature adjustment circuit to an output of 80% to 100% with respect to the maximum output. When the liquid temperature in the tank reaches or exceeds the target temperature, the four-way valve is switched to cool the liquid in the tank to the target temperature, and then the rotation speed of the compressor is controlled so that the liquid in the tank reaches the target temperature. In the case of a low liquid temperature and high load state, the number of revolutions of the compressor is controlled to control the liquid in the tank so that the liquid is maintained at the target temperature. In the case of the liquid temperature state, the compressor in the temperature adjustment circuit is set to an output of 80% to 100% with respect to the maximum output to rapidly heat the liquid in the tank, and the liquid temperature in the tank becomes equal to or higher than the target temperature. Control the number of rotations of the compressor to check the liquid in the tank. It may be characterized by controlling so as to maintain the temperature.
According to this configuration, particularly in the case of a low liquid temperature underload condition, the target temperature can be reached very quickly because it is heated once and then cooled to the target temperature.

  Further, the first threshold value may be 40 ° C., and the second threshold value may be 20 ° C.

A first temperature sensor provided substantially at the center in the horizontal direction of the tank, and a second temperature sensor provided in a flow pipe disposed downstream of the condenser, An average temperature of the temperatures measured by the first temperature sensor and the second temperature sensor is calculated, and the rotation speed of the compressor is set so that the calculated average temperature matches the temperature measured by the liquid temperature sensor. Control is performed to maintain the temperature of the liquid at the target temperature.
According to this, the target temperature can be accurately maintained.

Furthermore, a third temperature sensor for measuring the temperature of the heat medium flowing in the tank direction from the compressor is provided on the upstream side of the flow pipe provided in the tank when the inside of the tank is heated, When the temperature measured by the third temperature sensor exceeds a preset threshold value, the compressor may be controlled so as to reduce the rotational speed of the compressor.
According to this structure, it can prevent that the temperature of a liquid rises too much.

  In the liquid temperature adjusting device of the present invention, the liquid can be rapidly heated to the target temperature while reducing running costs and saving energy.

Preferred embodiments of a liquid temperature adjusting device according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 is an explanatory diagram showing the overall configuration of an embodiment of a liquid temperature adjusting device.
The liquid temperature adjusting device 30 of this embodiment includes a tank 31 that generates constant temperature water, and a temperature adjustment circuit 32 that adjusts the temperature of the constant temperature water in the tank 31.

In the tank 31, a constant-temperature water first distribution pipe 53 connected to the load 50 in order to distribute the constant-temperature water set at the target temperature in the tank 31 to the load 50 using the constant-temperature water, and the constant-temperature water discharged from the load 50. Is connected to the second flow pipe 55 for constant temperature water to flow into the tank 31 through the pump 52.
Moreover, the 1st constant temperature water flow pipe 53 and the 2nd constant temperature water flow pipe 55 are each attached to both the horizontal opposing surfaces of the tank 31 so that it may oppose on both sides of the tank 31.

  The temperature adjustment circuit 32 includes a compressor 34 that compresses the heat medium, a condenser 36 (40) that condenses the heat medium compressed by the compressor 34 into a liquid, and adiabatic expansion of the heat medium that releases heat from the condenser 36. And an evaporator 40 (36) for vaporizing the heat medium whose pressure has been reduced by the expander 38 and absorbing heat from the outside, and each component is a flow pipe for circulating the heat medium. 33 are connected to each other.

In addition, a four-way valve 66 is provided between the flow pipe 33 connected to the downstream side of the compressor 34 and the flow pipe 33 connected to the upstream side to switch the flow direction of the heat medium in the reverse direction.
By switching the four-way valve 66, the temperature adjustment circuit 32 is provided so that both heating and cooling can be controlled by one circuit. In the four-way valve 66, the flow pipe 33 on the upstream side of the compressor 34 is connected to the flow pipe 33 on the upstream side of the condenser 36 (downstream of the evaporator 36 during cooling) or the downstream side of the evaporator 40 (on the condenser 40 when cooled). Is connected to one of the flow pipes 33 on the upstream side), and the flow pipe 33 on the downstream side of the compressor 34 is connected to the flow pipe 33 on the upstream side of the condenser 36 (on the downstream side of the evaporator 36 during cooling) or evaporation. It arrange | positions so that it may connect with the other one of the flow pipes 33 of the downstream (upstream of the condenser 40 at the time of cooling) of the container 40. FIG. Then, the connection destination of the upstream side and downstream side distribution pipes 33 of the compressor 34 is controlled so that one side and the other side in the case described above are switched in reverse.

  When the tank 31 is heated, the heat medium compressed by the compressor 34 flows from the four-way valve 66 to the condenser 36, and the heat medium heat released by the condenser 36 is adiabatically expanded by the expander 38 to reduce the pressure. The heat medium whose pressure has been reduced by the expander 38 is vaporized and passes through the evaporator 40 that absorbs heat from the outside, and returns to the compressor 34 through the four-way valve 66.

When the tank 31 is cooled, the four-way valve 66 is switched to flow the heat medium in the direction opposite to the above-described direction. That is, the condenser 36 functions as an evaporator, and the evaporator 40 functions as a condenser.
First, the heat medium compressed by the compressor 34 flows from the four-way valve 66 to the condenser 40, and is released to the air by the fan 42. The heat medium released by the condenser 40 is adiabatically expanded by the expander 38 to reduce the pressure, and the evaporator 36 absorbs heat from the tank 31 and returns to the compressor 34 via the four-way valve 66.

In addition, the site | part shown as the condenser 36 in FIG. 1 is provided with the flow pipe 33 of the downstream of the compressor 34 meanderingly formed in the tank 31 inside.
During the heating of the tank 31, the condenser 36 exchanges heat between the heat medium compressed to a high temperature and the constant temperature water in the tank 31, and the heat medium radiates heat into the tank 31. For this reason, the constant temperature water in the tank 31 is heated.

Further, the evaporator 40 is provided as a heat exchanger configured by laminating a plurality of fins for increasing the contact area with air around the circulation pipe 33. Such an evaporator 40 is provided with a fan 42 and forcibly blows air toward the fins of the evaporator 40. For this reason, the heat medium exchanges heat with air, which is an external heat source, and the heat medium absorbs heat from the air. Thus, the temperature adjustment circuit 32 employs a heat pump circuit that sucks and uses heat from the air by the evaporator 40 when the tank 31 is heated, which can contribute to energy saving.
The heat medium that has absorbed heat and vaporized in the evaporator 40 returns to the compressor 34.

The temperature adjustment circuit 32 includes two bypass pipes 43 and 46 that connect the flow pipe 33 upstream of the condenser (evaporator) 36 and the flow pipe 33 downstream of the evaporator (condenser) 40. It is arranged.
These are a bypass pipe 43 used during heating and a bypass pipe 46 used during cooling.

  A relief valve 44 and a check valve 45 are provided in the middle of the bypass pipe 43 used for heating, and the relief valve 44 is normally closed, but the heat medium compressed by the compressor 34 When the pressure becomes higher than a predetermined value, the relief valve 44 is opened, and the high-pressure heat medium is released to the input side of the compressor 34.

  A relief valve 47 and a check valve 48 are also provided in the bypass pipe 46 used for cooling. In the normal state during cooling, the relief valve 47 is closed, but when the heat medium compressed by the compressor 34 has become a pressure higher than a predetermined value, the relief valve 47 is opened, The high-temperature heat medium is allowed to escape to the input side of the compressor 34.

Subsequently, a control system of the liquid temperature adjusting device 30 of the present embodiment will be described.
Temperature sensors 62, 63, 64, 65 are provided at four locations around the tank 31 and its periphery, and the controller 60 determines the number of rotations of the compressor 34 based on the detected temperature of each temperature sensor 62, 63, 64, 65. Control, switching of the four-way valve, and control of the rotational speed of the fan 42 of the evaporator 40 are performed.

  The control device 60 includes a CPU, a memory, a display unit, an input switch, and the like. The CPU reads out a control program stored in the memory and is based on temperature information from each temperature sensor 62, 63, 64, 65. Thus, the compressor 34, the four-way valve 66, and the fan 42 can be controlled.

A liquid temperature sensor 62 for measuring the temperature of the constant temperature water discharged from the tank 31 is provided in the first flow pipe for constant temperature water that is connected to the tank 31 and discharges the constant temperature water inside the tank 31. The liquid temperature is input to the control device 60.
A first temperature sensor 63 is attached to the outer wall surface of the tank 31 at approximately the center in the horizontal direction (approximately the center in the flow direction of the heat medium with respect to the tank 31). The temperature of the tank outer wall surface measured by the first temperature sensor 63 is input to the control device 60.

A second temperature sensor 64 is provided in the flow pipe 33 located on the downstream side of the condenser 36. The temperature of the flow pipe 33 measured by the second temperature sensor 64 (the temperature of the heat medium radiated by the condenser 36) is input to the control device 60.
A third temperature sensor 65 is provided in the flow pipe 33 located on the upstream side of the condenser 36. The temperature of the flow pipe 33 measured by the third temperature sensor 65 (the temperature of the heat medium compressed by the compressor 34) is input to the control device 60.

  FIG. 2 shows a graph representing the temperature rise when the target temperature is less than 40 ° C. and the temperature of the water before temperature adjustment is 5 ° C. In this graph, as an example, the target temperature is 30 ° C., and after 5 ° C. water is raised to 30 ° C., the temperature of 30 ° C. is maintained and constant temperature water is obtained.

  FIG. 3 is a graph showing a temperature rise when the target temperature is 40 ° C. or higher and the temperature of the constant temperature water before temperature adjustment is 20 ° C. In this graph, as an example, the target temperature is 60 ° C., 20 ° C. water is raised to 60 ° C., and then the temperature of 60 ° C. is maintained to obtain constant temperature water.

  Incidentally, the liquid temperature adjusting device 30 has a different control method depending on whether the target temperature is 40 ° C. or higher. Note that the target temperature is set by the user, and the user can cause the control device 60 to input the target temperature by operating an input switch (not shown). The target temperature is stored in a memory in the control device 60.

A control method of the liquid temperature adjusting apparatus of the present embodiment will be described based on the flowchart of FIG.
First, when the power supply of the liquid temperature adjusting device is turned on (step S100), the control device 60 reads the target temperature input by the user from the memory, and determines whether the target temperature is less than 40 ° C. or 40 ° C. or more ( Step S102).

Below, the control in case the target temperature is initially less than 40 degreeC is demonstrated.
When the target temperature is lower than 40 ° C., the control device 60 next calculates the temperature difference between the target temperature and the current liquid temperature of the water in the tank 31 (step S104). The current liquid temperature is based on the temperature input from the liquid temperature sensor 62.
The controller 60 determines whether or not the temperature difference is 20 ° C. or more (step S106). If the temperature difference is 20 ° C. or more, the control device 60 causes the temperature adjustment circuit 32 to output 80% to 100% of the compressor 34 with respect to the maximum output (for example, 5000 to 6000 rpm with respect to 2500 to 3500 rpm in normal times). ) So that rapid heating of the water in the tank 31 is started (step S108).

  During the heating, the control device 60 constantly checks the liquid temperature and determines whether or not the liquid temperature has become equal to or higher than the target temperature (step S110). Then, the control device 60 outputs a control signal to the four-way valve 66 so that the four-way valve 66 is switched when the liquid temperature reaches the target temperature. When the four-way valve 66 is switched, the water in the tank 31 is controlled to cool (step S112). Thereby, the temperature of the water in the tank 31 approaches the target temperature.

  Thereafter, the control device 60 calculates the average temperature measured by the first temperature sensor 63 and the second temperature sensor 64 (step S114). Then, the control device 60 controls the rotation speed of the compressor 34 so that the average temperature of the first temperature sensor 63 and the second temperature sensor 64 matches the current temperature of the water measured by the liquid temperature sensor 62. Thus, the temperature of the water in the tank 31 is maintained at the target temperature, and constant temperature water is generated (step S116).

When it is determined in step S106 that the temperature difference between the target temperature and the current liquid temperature of the water in the tank 31 is less than 20 ° C., the process proceeds to step S112, and the control device 60 includes the temperature adjustment circuit. 32 controls the tank 31 to cool.
Then, the process proceeds to step S <b> 114, and the CPU of the control device 60 calculates the average temperature measured by the first temperature sensor 63 and the second temperature sensor 64.
Further, the process proceeds to step S116, where the control device 60 causes the compressor 34 so that the average temperature of the first temperature sensor 63 and the second temperature sensor 64 matches the current temperature of the water measured by the liquid temperature sensor 62. Is controlled to maintain the temperature of the water in the tank 31 at the target temperature, and constant temperature water is generated.

Then, the case where target temperature is 40 degreeC or more is demonstrated.
When it is determined in step S102 that the target temperature is 40 ° C. or higher, the control device 60 sets the temperature adjustment circuit 32 so that the compressor 34 has an output of 80% to 100% of the maximum output. It controls to start the rapid heating of the water in 31 (step S200).

During the heating, the control device 60 constantly checks the liquid temperature, and when the liquid temperature becomes equal to or higher than the target temperature, the rapid heating by the output of 80% to 100% of the compressor 34 is stopped to control the rotation speed. Transition is made (step S202).
That is, the control device 60 calculates the average temperature of the temperatures measured by the first temperature sensor 63 and the second temperature sensor 64 (step S114). Then, the control device 60 controls the rotation speed of the compressor 34 so that the average temperature of the first temperature sensor 63 and the second temperature sensor 64 matches the current temperature of the water measured by the liquid temperature sensor 62. Thus, the temperature of the water in the tank 31 is maintained at the target temperature, and constant temperature water is generated (step S116).

As described above, when the target temperature is high, the liquid temperature is naturally lowered by the outside air without performing the cooling control, so that it is not necessary to perform the cooling control by switching the four-way valve 66.
On the other hand, when the target temperature is relatively low (similar to the outside air temperature), the liquid temperature is unlikely to decrease. Therefore, it is necessary to switch the four-way valve 66 and perform cooling control to maintain the target temperature.

  During heating, if the temperature of the air in contact with the evaporator 40 is low, sufficient heat absorption may not be possible, so the control device 60 performs control so as to reduce the rotational speed of the fan 42. Further, when the temperature of the air contacting the evaporator 40 is high, the control device 60 may perform control so as to increase the rotational speed of the fan 42 in order to increase the heat absorption efficiency.

  Further, a threshold value of the temperature of the heat medium measured by the third temperature sensor 65 is stored in the control device 60 in advance. While the temperature of the water in the tank 31 is being increased, the control device 60 compares the temperature of the heat medium measured by the third temperature sensor 65 with a threshold value. When the control device 60 detects that the temperature of the heat medium measured by the third temperature sensor 65 exceeds the threshold value, the control device 60 performs control so as to reduce the rotational speed of the compressor 34. By executing such control, bumping due to a sudden rise in the temperature of water can be avoided. Further, when the liquid to be heated is other than water, it is possible to prevent the liquid from being altered.

  Note that it is preferable that the compressor 34 can be controlled by inverter control because precise temperature adjustment and energy saving can be performed. That is, the rotation drive of the compressor 34 is performed by a motor (not shown), and the rotation control of the motor is preferably performed by the inverter circuit 68.

  In the embodiment described above, an example in which water is heated in the tank 31 to generate constant temperature water has been described. However, the liquid to be heated is not limited to water, and may be other liquids. For example, you may employ | adopt when maintaining the milk after milking at a fixed temperature.

  In the above-described embodiment, the configuration in which the constant temperature water generated in the tank 31 is supplied to the load has been disclosed. However, the configuration may be employed in which only the liquid is stored in the tank 31.

It is explanatory drawing which shows the whole structure of embodiment of the liquid temperature control apparatus in this invention. It is explanatory drawing which shows the temperature rise graph in case target target temperature is less than 40 degreeC. It is explanatory drawing which shows the temperature rise graph in case target target temperature is 40 degreeC or more. It is a flowchart which shows the control method of a liquid temperature control apparatus. It is explanatory drawing which shows the structure of the conventional liquid temperature control apparatus.

Explanation of symbols

30 Liquid temperature adjusting device 31 Tank 32 Temperature adjusting circuit 33 Flow pipe 34 Compressor 36 Condenser (evaporator)
38 Expander 40 Evaporator (Condenser)
42 Fan 43, 46 Bypass pipe 44, 47 Relief valve 45, 48 Check valve 50 Load 52 Pump 53 First flow pipe for constant temperature water 55 Second flow pipe for constant temperature water 60 Control device 62 Liquid temperature sensor 63 First temperature sensor 64 Second temperature sensor 65 Third temperature sensor 66 Four-way valve 68 Inverter circuit

Claims (5)

In the liquid temperature adjusting device provided with a control device for controlling the liquid in the tank to be heated to the target temperature,
A compressor that compresses the heat medium, a condenser that condenses the heat medium into a liquid, an expander that lowers the heat medium, and an evaporator that vaporizes the heat medium are connected by a flow pipe through which the heat medium flows. A temperature adjustment circuit is provided,
A four-way valve for reversing the flow direction of the heat medium of the temperature adjustment circuit is provided,
A part of the flow pipe is attached to the outer wall surface of the tank or disposed inside the tank, and functions as a condenser or an evaporator of the temperature adjustment circuit to heat or cool the liquid in the tank. Provided,
When heating the tank, the evaporator is provided to absorb heat from an external heat source, so that the temperature adjustment circuit is provided to constitute a heat pump circuit,
A liquid temperature sensor for measuring the liquid temperature in the tank is provided;
The control device includes:
When the target temperature is less than a preset first threshold and the temperature difference between the target temperature and the liquid temperature before temperature adjustment is less than a preset second threshold, the low liquid temperature Judge that it is underload,
When the target temperature is less than a preset first threshold and the temperature difference between the target temperature and the liquid temperature before temperature adjustment is equal to or greater than a preset second threshold, the low liquid temperature Judging that the load is high,
When the target temperature is equal to or higher than a preset first threshold, it is determined that the liquid temperature state is high,
A liquid temperature adjusting device that executes different control methods for a low liquid temperature underload state, a low liquid temperature high load state, and a high liquid temperature state. The control device includes:
In the case of a low liquid temperature underload condition, the temperature adjustment circuit compressor is set to an output of 80% to 100% of the maximum output to rapidly heat the liquid in the tank, and the liquid temperature in the tank is the target temperature. When this occurs, the four-way valve is switched to cool the liquid in the tank to the target temperature, and thereafter, the number of revolutions of the compressor is controlled so that the liquid in the tank is maintained at the target temperature. ,
In the case of a low liquid temperature and high load state, the control is performed so that the liquid is maintained at the target temperature while cooling the liquid in the tank by controlling the rotation speed of the compressor,
In the case of a high liquid temperature state, the liquid in the tank is rapidly heated by setting the compressor of the temperature adjustment circuit to an output of 80% to 100% with respect to the maximum output, and the liquid temperature in the tank exceeds the target temperature. 2. The liquid temperature adjusting device according to claim 1, wherein when it becomes, the rotation speed of the compressor is controlled so that the liquid in the tank is maintained at a target temperature.   3. The liquid temperature adjusting apparatus according to claim 1, wherein the first threshold value is 40 ° C., and the second threshold value is 20 ° C. 4. A first temperature sensor provided at substantially the center in the horizontal direction of the tank;
A second temperature sensor provided in a flow pipe disposed downstream of the condenser;
The control device includes:
An average temperature of the temperatures measured by the first temperature sensor and the second temperature sensor is calculated, and the rotation speed of the compressor is set so that the calculated average temperature matches the temperature measured by the liquid temperature sensor. 4. The liquid temperature adjusting device according to claim 1, wherein the liquid temperature adjusting device is controlled to maintain the temperature of the liquid at a target temperature. A third temperature sensor for measuring the temperature of the heat medium flowing in the tank direction from the compressor is provided on the upstream side of the flow pipe provided in the tank when heating the inside of the tank,
The control device includes:
5. The liquid temperature adjusting device according to claim 4, wherein when the temperature measured by the third temperature sensor exceeds a preset threshold value, control is performed so as to reduce the rotational speed of the compressor.

Images