JP2005241113A - Isothermal refrigeration device and its temperature control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely manage a temperature while reducing the noise from a stirling freezer in an isothermal refrigeration device having a cooling storage, the stirling freezer for cooling the inside of the cooling storage and a control circuit, and its temperature control method. <P>SOLUTION: The input electric power to the stirling freezer 2 is controlled on the basis of a unit time Ta and/or a unit electric power Wa of a rough control step by a freezer control circuit part 14 of the control circuit 3, and the input electric power to a heater 13 is controlled on the basis of a unit time Tb and/or a unit electric power Wb of a fine control step by a heater control circuit part 15 of the control circuit 3, whereby the temperature in the cooling storage 1 can be precisely controlled while using the stirling freezer 2 in which fine adjustment of cooling capacity by fine adjustment of input electric power is difficult. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to temperature control of a constant-temperature refrigeration apparatus using a Stirling refrigerator that can be used in any industrial field such as medical, pharmaceutical, bio-industry, semiconductor manufacturing, or industrial or household equipment such as environmental testing, and the like. The present invention relates to a temperature control method.

Conventionally, as a refrigeration apparatus using this type of Stirling refrigerator, a Stirling cooling apparatus that cools a heat utilization device (corresponding to the refrigerator of the present invention) by cold heat generated by the Stirling refrigerator is known (for example, Patent Documents 1 and 2). In addition, the heat utilization device (corresponding to the refrigerator of the present invention) is cooled by the cold generated by the Stirling refrigerator, and at the same time, the heater is turned on / off or the inverter pulse is controlled to adjust the cooling temperature and the heater uses the heat. A Stirling refrigerator-based constant temperature liquid circulation device that can accurately control the temperature of the heat-utilizing device by heating the device is known (for example, see Patent Document 3).
JP 11-223404 A JP 2001-355513 A Japanese Patent No. 3280922

  However, in the Stirling cooling devices of Patent Documents 1 and 2, there is a problem that vibration and noise of the Stirling refrigerator are increased by performing drive control of the Stirling refrigerator. When adjusting the refrigeration capacity of the Stirling refrigerator in order to adjust the temperature of the heat utilization device, the amplitude of the Stirling refrigerator piston and displacer is changed by adjusting the power input to the Stirling refrigerator. Since it is necessary to adjust the refrigeration capacity of the Stirling refrigerator by changing the power input to the Stirling refrigerator frequently during the driving period of the Stirling refrigerator, the amplitude of the piston changes. This is because a “beat” occurs due to a slight delay due to inertia in tracking the amplitude of the displacer.

  In order to solve such a problem, in Patent Document 3, heat utilization equipment is heated by a heater, and temperature management is precisely performed by combining cooling and heating.

  By the way, in this type of constant temperature refrigeration apparatus with relatively precise temperature management, for example, in which the temperature is managed in units of at least 0.1 ° C., the inside of the refrigerator is simply controlled by on / off control of the heater or inverter pulse control. It was insufficient to adjust the temperature.

  The problems to be solved by the present invention are a constant temperature refrigeration apparatus having a refrigerator, a Stirling refrigerator for cooling the interior of the refrigerator, and a control circuit for controlling the operation of the refrigerator, and its In the temperature control method, temperature management can be performed accurately while suppressing vibration and noise.

  The invention of claim 1 is a constant temperature refrigeration apparatus comprising a refrigerator, a Stirling refrigerator for cooling the interior of the refrigerator, and a control circuit for controlling the operation of the refrigerator. A refrigerator control circuit unit for driving and controlling the Stirling refrigerator, and a heater control circuit unit with a control step finer than the control step of the refrigerator control circuit unit, and controlled by the heater control circuit unit The constant temperature refrigeration apparatus is provided with a heater provided in the refrigerator.

  The invention of claim 2 is characterized in that the control step is time, and the unit time of control of the heater is set smaller than the unit time of control of the Stirling refrigerator. It is.

  According to a third aspect of the invention, the constant temperature refrigeration apparatus according to the first aspect, wherein the control step is electric power, and the unit power for controlling the heater is set smaller than the unit power for controlling the Stirling refrigerator. It is.

  Invention of Claim 4 is the temperature control method of the constant temperature refrigerator which has a refrigerator, the Stirling refrigerator for cooling the inside of this refrigerator, and the control circuit for controlling the operation of the refrigerator, A heater for adjusting the temperature in the refrigerator is provided in the refrigerator, and the Stirling refrigerator and the heater are simultaneously operated at least in a constant temperature region, and the unit time and / or unit power of the Stirling refrigerator is controlled more than A temperature control method for a constant-temperature refrigeration apparatus, wherein the Stirling refrigerator and the heater are operated by reducing a unit time and / or unit power of the heater control.

  According to the first aspect of the present invention, the piston that physically vibrates inside the Stirling refrigerator at least in the constant temperature region due to the heat generated by the small heater by the heater control step finer than the control step of the refrigerator control circuit unit. It is possible to precisely control the internal temperature without changing the amplitude of vibration elements such as a display and the like. In addition, the heater used for fine adjustment of the temperature in the refrigerator is controlled in small steps with fine control steps, so that the power consumed by this heater can be kept small, thereby reducing the consumption of the constant temperature refrigeration system as a whole. An increase in power can be minimized.

  According to the invention of claim 2, the heater control circuit unit performs the control of the heater a plurality of times within a unit time of the control of the Stirling refrigerator by the refrigerator control circuit unit, so that at least in a constant temperature region. The fine adjustment of the temperature in the refrigerator can be relatively easily performed by fine control of the heater without changing the amplitude of the vibration element of the Stirling refrigerator.

  According to the invention of claim 3, the electric power applied to the heater by the heater control circuit unit without finely controlling the amplitude of the vibration element such as a piston or a displacer that physically vibrates inside the Stirling refrigerator. By finely controlling the temperature, the fine adjustment of the temperature in the refrigerator can be performed relatively easily by fine control of the heater without changing the amplitude of the vibration element of the Stirling refrigerator at least in the constant temperature range. Can do.

  According to the invention of claim 4, the piston that physically vibrates inside the Stirling refrigerator at least in the constant temperature region due to heat generated by the small heater by the heater control step finer than the control step of the refrigerator control circuit unit. It is possible to precisely control the internal temperature without changing the amplitude of vibration elements such as a display and the like. In addition, the heater used for fine adjustment of the temperature in the refrigerator is controlled in small steps with fine control steps, so that the power consumed by this heater can be kept small, thereby reducing the consumption of the constant temperature refrigeration system as a whole. An increase in power can be minimized.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all of the configurations described below are not necessarily essential requirements of the present invention.

  FIG. 1 shows Example 1, and a constant temperature refrigeration apparatus includes a refrigerator 1, a Stirling refrigerator 2 for cooling the inside of the refrigerator 1, and a control for controlling the operation of the refrigerator 1. And a control circuit 3 as means. The cooler 1 has an insulating box 6 formed by surrounding a container 5 having an opening 4 on the upper side and an accommodating space on the inside with a heat insulating member (not shown), and the opening 4 of the container 5. It consists of the cover body 7 which has the heat insulation which can be obstruct | occluded. The Stirling refrigerator 2 is connected to the Stirling refrigerator main body 8, the condenser 9 attached to the Stirling refrigerator main body 8, the liquid pipe 10 connected to the condenser 9, and the liquid pipe 10. An evaporation pipe 11, a gas pipe 12 connected between the evaporation pipe 11 and the condenser 9, and a path formed by the condenser 9, the liquid pipe 10, the evaporation pipe 11, and the gas pipe 12 And a refrigerant (not shown). When the refrigerant enclosed in the path is condensed by the condenser 9 by the cold heat generated by the Stirling refrigerator main body 8, discharged from the liquid pipe 10, and vaporized again in the evaporation pipe 11. The container 5 and thus the internal space of the container 5 is deprived of heat and returned to the condenser 9 from the gas pipe 12 to return the container 5 and the internal space of the container 5 in contact with the evaporation pipe 11. It is to be cooled.

  Further, on the outer periphery of the container 5, for example, a band-shaped electric heater 13 for adjusting the temperature by heating the container 5, and by extension, the internal space of the container 5 is provided. The control circuit 3 includes a refrigerator control circuit unit 14 for driving and controlling the Stirling refrigerator main body 8 and a heater control circuit unit 15 for controlling the heat generation of the heater 13, and further includes the control circuit. 3 is connected to a temperature sensor 16 for measuring the temperature in the container 5 and to a temperature setting means 17 provided outside the box 6. The refrigerator control circuit unit 14 is provided to allow an alternating current to flow through an electromagnetic coil, which will be described later, provided in the Stirling refrigerator main body 8, and the Stirling refrigerator 8 by the refrigerator control circuit unit 14 is provided. When the cooling capacity per unit time for the container 5 is Q (J / second), and the heating capacity per unit time for the container 5 of the heater 13 by the heater control circuit 15 is P (J / second), The numerical value of the heating capacity P is controlled to be smaller than the numerical value of the cooling capacity Q.

  The Stirling refrigerator 2 will be described with reference to FIG. Reference numeral 21 denotes a casing composed of a cylindrical portion 22 and a body portion 23 formed in a substantially cylindrical shape. The cylindrical portion 22 is made of stainless steel or the like, and a base portion 24, an intermediate portion 25, and a distal end portion 26 are integrally formed. The body portion 23 is divided into upper and lower casings 23A and 23B, and the upper casing 23A is formed integrally with the cylindrical portion 22. Inside the cylindrical portion 22, a cylinder 27 extending to the barrel portion 23 is provided so as to be coaxially inserted with respect to the cylindrical portion 22. On the distal end portion 26 side of the cylinder 27, the cylinder 27 is provided. A separate extension cylinder portion 27A is connected coaxially. The cylinder 27 on the body 23 side is formed by casting die casting or the like using a metal such as aluminum, and the inner and outer circumferences of the cylinder 27 are cut after casting. It is. A displacer 28 is slidably accommodated in the axial direction on the distal end side of the cylinder 27 and on the inner side of the extension cylinder 27A. An expansion chamber E is formed between the distal end of the displacer 28 and the distal end portion 26 of the cylindrical portion 22, and the inside and outside of the extension cylinder 27 </ b> A are communicated by a gap 29. In addition, a regenerator 30 is provided between the intermediate portion 25 and the outer periphery of the cylinder 27, and a communication hole 31 that communicates the inside and outside of the cylinder 27 is formed in the cylinder 27 itself in the base portion 24. Has been. Further, a heat-absorbing fin 32 is provided between the inner periphery of the distal end portion 26 of the cylindrical portion 22 and the outer periphery of the distal end of the extension cylinder 27A, and the cylindrical portion is interposed between the regenerator 30 and the communication hole 31. Radiating fins 33 are provided between the inner circumference of 22 and the outer circumference of the cylinder 27. A path 34 is formed from the inner tip of the extension cylinder 27A to the compression chamber C in the cylinder 27 through the gap 29, the heat absorbing fin 32, the regenerator 30, the heat radiating fin 33, and the communication hole 31. Has been. Further, a piston 35 is accommodated in the trunk portion 23 inside the base end side of the cylinder 27 so as to be slidable in the axial direction. The base end portion of the piston 35 is coaxially connected to the drive mechanism 36.

  The drive mechanism 36 is connected to the base end of the piston 35 by a connecting body 35A, and has a short cylindrical frame 37 extending coaxially around the base end side of the cylinder 27, and the frame 37. A short cylindrical permanent magnet 38 fixed to the tip side of the magnet, an annular electromagnetic coil 39 provided close to the outer periphery of the permanent magnet 38, and an inner periphery of the permanent magnet 38. It is comprised with the magnetism part 40. A first leaf spring 41 for controlling the operation of the piston 35 is connected to a connecting body 35A for connecting the frame 37 to the piston 35. Further, one end of a rod 42 for controlling the operation of the display sensor 28 is connected to the proximal end side of the display sensor 28, and a second leaf spring 43 is connected to the other end of the rod 42. It is connected. The rod 42 extends through the piston 35. The pair of leaf springs 41 and 43 are disposed outside the base end side of the cylinder 27 in the body portion 23, and the second leaf spring 43 is more than the first leaf spring 41. It is arranged at a position away from the base end side of the cylinder 7. The electromagnetic coil 39 is provided so as to be wound around the electromagnetic core 44, and the electromagnetic core 44 is integrated with the electromagnetic coil 39 and the like.

  An external heat radiation fin 45 is attached to the outer periphery of the base portion 24 of the cylindrical portion 22 of the casing 21 in a heat transfer manner. The condenser 9 is attached to the outer periphery of the distal end portion 26 of the cylindrical portion 22 in a heat transfer manner. Further, a vibration absorbing unit 46 is provided outside the body 23 of the casing 21 so as to be substantially coaxial with the cylinder 27, the displacer 28 and the piston 35.

  Next, the effect | action of a present Example is demonstrated based on FIG. First, the user operates the temperature setting means 17 to operate the Stirling refrigerator main body 8. When an alternating current is passed through the electromagnetic coil 39 of the Stirling refrigerator main body 8 by the refrigerator control circuit unit 14, an alternating magnetic field is generated, and this alternating magnetic field generates a force for reciprocating the permanent magnet 38 in the axial direction. Occur. This force causes the piston 35 to reciprocate in the cylinder 27 in the axial direction. When the piston 35 moves in the direction approaching the displacer 28, the gas in the compression chamber C formed between the piston 35 and the displacer 28 is compressed, and the communication hole 31, the heat radiating fins are compressed. 33, the regenerator 30, the endothermic fin 32, and the gap 29 to reach the expansion chamber E formed between the distal end of the displacer 28 and the distal end portion 26 of the cylindrical portion 22, and the displacer Press 28 down. On the other hand, when the piston 35 moves in a direction away from the displacer 28, the inside of the compression chamber C becomes negative pressure, and the gas flows from the expansion chamber E to the gap 29, the heat absorption fin 32, the regenerator 30. Then, the heat is returned to the compression chamber C in the cylinder 27 through the heat radiating fins 33 and the communication holes 31, thereby pushing up the displacer 28. During this process, a reversible cycle consisting of two isothermal changes and an isovolume change is performed, so that the heat-absorbing fins 32 attached to the outer periphery of the tip of the cylinder 27 are cooled to cool the condenser 9. On the other hand, the external radiating fins 45 attached to the outer periphery of the base portion 24 become high temperature. The Stirling refrigerator main body 8 adjusts the power value while maintaining the frequency of the alternating current input to the electromagnetic coil 39, so that the frequency of the piston 35 and the displacer 28 is maintained at a predetermined value. The amplitudes of the piston 35 and the displacer 28 are changed, and the refrigerating capacity of the Stirling refrigerator main body 8 is adjusted. The vibration of the predetermined frequency of the piston 35 and the displacer 28 can be absorbed by the vibration absorbing unit 46.

  Then, the cold heat generated at the tip portion 26 of the Stirling refrigerator main body 8 moves to the condenser 9 and condenses the refrigerant in the condenser 9. The condensed refrigerant is discharged from the liquid pipe 10 and flows down, vaporizes again in the evaporation pipe 11, and returns to the condenser 9 from the gas pipe 12 again. And when the said refrigerant | coolant vaporizes in the said evaporation pipe | tube 11, the said container 5 by which the heat | fever in the said container 5 and by extension, the inner space of this container 5 was taken away as vaporization heat, and by extension The internal space of the container 5 is cooled.

  In the initial stage of cooling the container 5 of the refrigerator 1, the maximum rated power Wamax is input to the Stirling refrigerator main body 8. Then, the control circuit 3 refers to the temperature signal of the internal temperature D from the temperature sensor 16 so that the refrigerator control circuit unit 14 performs the Stirling in a control step of unit power Wa every unit time Ta. The electric power input to the refrigerator main body 8 is controlled. For example, when the unit time Ta is 600 seconds, the unit power Wa is 2 W, and the maximum rated power Wamax is 40 W, the control circuit 3 inputs 40 W AC power to the Stirling refrigerator main body 8 in the initial stage of cooling. The input power is controlled in increments of 2 W while referring to the temperature signal from the temperature sensor 16 every 600 seconds.

  When the temperature of the container 5 of the refrigerator 1 reaches a constant temperature region near the temperature set by the temperature setting means 17, electric power is input to the heater 13 by the heater control circuit unit 15 of the control circuit 3. The Then, the control circuit refers to the temperature signal of the internal temperature D from the temperature sensor 16, so that the heater control circuit unit 15 causes the heater 13 to perform the control step of unit power Wb every unit time Tb. The input power is controlled. The unit time Ta and the unit power Wa of the control of the Stirling refrigerator main body 8 are Ta = mTb (m is a natural number) and Wa = nWb (n) compared to the unit time Tb and unit power Wb of the heater control. Is a natural number). The maximum rated power Wbmax of the heater 13 is set to be the same as the unit power Wa of the control of the Stirling refrigerator main body 8. That is, when the Stirling refrigerator main body 8 is controlled as described above, for example, the unit time Tb is set to 60 seconds, the unit power Wb is set to 0.1 W, and the maximum rated power Wbmax is set to 2 W. In this example, when the refrigerator control circuit unit 14 is cooled only by the Stirling refrigerator 2, the temperature in the container 5 is the smallest among the electric power set in increments of 2W at which the temperature is equal to or lower than a preset temperature. The Stirling refrigerator main body 8 is driven by electric power Wax. At the same time, the heater control circuit unit 15 inputs electric power Wbx set in increments of 0.1 W to the heater 13. Thereby, the internal space of the container 5 of the refrigerator 1 is a difference power (Wax−Wbx) between the power input to the Stirling refrigerator main body 8 and the power input to the heater 13 in a constant temperature region. This is almost equivalent to being cooled by the Stirling refrigerator 2. In this example, since the unit time Tb (= 60 seconds) for controlling the heater 13 is 10 times during the unit time Ta (= 600 seconds) for controlling the Stirling refrigerator main body 8, the Stirling refrigeration is performed. Before the electric power input to the machine main body 8 is changed, the temperature inside the container 5 is finely adjusted by the heater 13 so that it is not necessary to change the electric power input to the Stirling refrigerator main body 8. In the constant temperature range, the amplitude of the piston 35 and the displacer 38 of the Stirling refrigerator main body 8 is made substantially constant, and the “beat” generated when the amplitude of the piston 35 and the displacer 38 of the Stirling refrigerator main body 8 changes. Such noise can be suppressed at least in a constant temperature range.

  That is, it is difficult to finely control the amplitude of the piston 35 and the displacer 38 that physically reciprocates in the Stirling refrigerator main body 8 with electric power. Even if controlled, not only the cost of the control circuit 3 is increased, but also noise is generated every time the amplitude of the piston 35 and the displacer 38 is changed, but the heater 13 can easily control the power finely. Are simultaneously operated by the heater control circuit unit 15 to suppress noise of the Stirling refrigerator main body 8 in a constant temperature region by the inexpensive control circuit 3 and at the same time substantially reduce the amplitude of the piston 35 and the displacer 38. To obtain the same effect as finely controlling the temperature in the container 5 of the refrigerator 1 precisely. It can be. At this time, the unit time for controlling the Stirling refrigerator main body 8 and the heater 13 is Ta = mTb (m is a natural number), so that a plurality of heaters can be used within the unit time Ta for controlling the Stirling refrigerator main body 8. The temperature in the container 5 can be precisely adjusted by the heater 13 so as not to change the input power to the Stirling refrigerator main body 8 as much as possible. Therefore, the Stirling refrigeration is performed in a constant temperature range. Generation of noise can be suppressed by keeping the amplitudes of the piston 35 and the displacer 38 of the machine body 8 substantially constant.

  In this example, the total power consumption of the Stirling refrigerator 2 and the heater 13 is Wax + Wbx, which means that 2 Wbx of extra power is consumed relative to the power consumption Wax−Wbx for cooling. , Wbx itself is about 2 W at the maximum (minimum 0.1 W) and is relatively small with respect to the power consumption of the Stirling refrigerator 2, so that the extra power consumption for cooling can be kept low.

  As described above, in the embodiment, the input power to the Stirling refrigerator 2 is controlled by the refrigerator control circuit unit 14 of the control circuit 3 in a rough control step, and the heater control circuit unit 15 of the control circuit 3 finely controls the input power. By controlling the input power to the heater 13 in the control step, the temperature in the refrigerator 1 is precisely controlled while using the Stirling refrigerator 2 in which the fine adjustment of the cooling capacity by the fine adjustment of the input power is difficult. It is something that can be done.

  In the embodiment, the control unit time Tb of the heater 13 is set smaller than the control unit time Ta of the Stirling refrigerator 2, and the heater 13 is controlled within the control unit time Ta of the Stirling refrigerator 2. Is controlled a plurality of times, and before the refrigerator control circuit unit 14 changes the power input to the Stirling refrigerator 2, the input power to the Stirling refrigerator 2 is as much as possible. Since the heater control circuit unit 15 can precisely adjust the temperature in the container 5 with the heater 13 so as not to fluctuate, the generation of noise from the Stirling refrigerator 2 can be suppressed in a constant temperature range. It is.

  Moreover, in the said Example, by setting the unit power Wb of the control of the said heater 13 smaller than the unit power Wa of the control of the said Stirling refrigerator 2, it is fine below the coarse unit power Wa increment of the said Stirling refrigerator 2. The inside of the refrigerator 1 can be cooled in increments of unit power.

  In addition, this invention is not limited to the above Example, A various deformation | transformation is possible within the range of the summary of invention. For example, in the above embodiment, the unit time for controlling the Stirling refrigerator is an integral multiple of the unit time for controlling the heater, but in short, there are a plurality of heater controls within the unit time for controlling the Stirling refrigerator. It suffices if the conditions are satisfied, that is, the condition that Ta> 2Tb is satisfied. Furthermore, in the above embodiment, the two control steps of the unit time and the unit power of the heater are finely set with respect to the two control steps of the unit time and the unit power of the Stirling refrigerator, but as shown in FIG. Wa = Wb, Ta >> Tb, or Wa >> Wb, Ta = Tb as shown in FIG. Further, the unit power Wa may not be an integral multiple of the unit power Wb.

1 is an overall perspective view showing an embodiment of the present invention. It is sectional drawing of the Stirling refrigerator main body which shows the Example of this invention. It is a control block diagram which shows the Example of this invention. It is a time chart which shows the Example of this invention. It is a time chart which shows the other Example of this invention. It is a time chart which shows further another Example of this invention.

Explanation of symbols

1 Refrigerator 2 Stirling refrigerator 3 Control circuit
13 Heater
14 Refrigerator control circuit
15 Heater control circuit section Ta Tb Unit time (control step)
Wa Wb Unit power (control step)

Claims (4)

  In a constant temperature refrigeration apparatus having a refrigerator, a Stirling refrigerator for cooling the inside of the refrigerator, and a control circuit for controlling the operation of the refrigerator, the control circuit drives the Stirling refrigerator A refrigerator control circuit unit for controlling and a heater control circuit unit with a control step finer than the control step of the refrigerator control circuit unit, and a heater controlled by the heater control circuit unit in the refrigerator A constant temperature refrigeration apparatus provided.   2. The constant temperature refrigeration apparatus according to claim 1, wherein the control step is time, and the unit time for controlling the heater is set smaller than the unit time for controlling the Stirling refrigerator.   2. The constant temperature refrigeration apparatus according to claim 1, wherein the control step is electric power, and the unit power for controlling the heater is set smaller than the unit power for controlling the Stirling refrigerator.   In the temperature control method of a constant temperature refrigeration apparatus having a refrigerator, a Stirling refrigerator for cooling the inside of the refrigerator, and a control circuit for controlling the operation of the refrigerator, A heater for adjusting the temperature is provided, and the Stirling refrigerator and the heater are simultaneously operated at least in a constant temperature region, and the unit time and / or unit power of the Stirling refrigerator is more controlled than the unit time and power of the Stirling refrigerator. A temperature control method for a constant-temperature refrigeration apparatus, wherein the Stirling refrigerator and the heater are operated by reducing unit power.

Images