JPWO2007138761A1 - Temperature chamber - Google Patents

Abstract

An object of the present invention is to extend the life of a component disposed inside a thermostat having a double structure. A first thermostat 10 includes a first temperature control mechanism (11, 12, 13, 15a) and controls temperature at a first set temperature, and is disposed in the first thermostat 10. In the thermostat having a double structure including the second thermostat having the second temperature control mechanism (21, 22, 23, 15b) and controlling the temperature at the second set temperature, the second set temperature and It sets so that the 1st preset temperature may become higher than the temperature of the environment where a thermostat is installed.

Description

  The present invention relates to a thermostatic bath for keeping an analytical instrument at a constant temperature.

  Detection elements (such as a diode array and a photomultiplier) used in an analytical instrument are usually provided inside a housing having a temperature control mechanism that keeps the ambient temperature constant in order to improve the accuracy and reproducibility of analysis. By keeping the temperature inside the case constant, even if the room temperature (environmental temperature, generally about 25 ° C) of the laboratory where the analytical instrument itself is installed changes, the thermal effect transmitted to the detection element is affected. Reduced. Therefore, it is possible to obtain a result with good accuracy and reproducibility.

  Specifically, a thermostat is formed by arranging a temperature control mechanism for adjusting the temperature of the detection element together with the detection element in the casing of the analytical device, and covering the casing with a heat insulating material. As an example, FIG. 3 shows a schematic diagram of a conventional thermostat used in a spectrophotometer. In this example, the spectroscopic unit 1 includes a detection element and a mirror, and controls the temperature of the spectroscopic unit 1. For temperature control, a heater 11 that heats the air in the casing and a fan 12 that blows air to the heater 11 and circulates the air in the casing (arrow A) are provided, and the thermostatic chamber is warmed. The temperature inside the thermostatic chamber is measured by the temperature sensor 13, and the heater 15 is turned ON / OFF by the controller 15 so that the temperature inside the housing is maintained at a desired set temperature. Since temperature control is performed so that the temperature is kept constant by a thermostatic chamber formed in the analytical instrument, a good analysis result can be obtained.

  When the temperature change of the environment where the analytical instrument is placed is large, the ability of the temperature control mechanism is insufficient, the temperature cannot be kept constant, and the thermostat does not function. Although it is possible to install the analytical instrument in a temperature-controlled room where the temperature is kept constant, it is not efficient in terms of facility operation and power consumption. Therefore, there is a thermostat which is further formed in a thermostat formed in an analytical instrument, and the thermostat is controlled in a double structure. In this way, even if the environmental temperature change is large, the inside of the thermostat installed inside is hardly affected.

This thermostat bath having a double structure is very effective when used in an analysis apparatus in which the temperature of the sample itself greatly affects the analysis result, for example, in the case of a differential refractive index detector for liquid chromatograph. It is known that the temperature is controlled by arranging a detection unit (flow cell and detection element) in the inner temperature chamber, and the temperature of the pipe through which the sample flowing into the flow cell passes in the outer temperature chamber (patent) Reference 1). In FIG. 4, the thermostat of patent document 1 is shown. A heater 31 and a temperature sensor 33 are disposed inside the first (outside) thermostat 30, the temperature control unit 61 controls the temperature inside the first thermostat, and the second thermostat 40 has a heater 41, a temperature sensor 43 is provided, and the temperature controller 61 controls the temperature of the second thermostatic chamber 40. The sample flowing from the outside of the first thermostat 30 through the pipe 35 is rapidly heated in the first thermostat 30 and further heated in the second thermostat 40. By doing so, the change in the sample temperature is reduced. Further, in this example, a heater 51 and a temperature sensor 53 are disposed in the vicinity of the detection unit 36 in the second constant temperature bath 40, and the temperature control of the detection unit 36 is performed supplementarily by the detection unit temperature control unit 62. The time to reach a desired set temperature for analysis is shortened.
JP-A-11-201957

  Some detection elements have reduced noise when used at low temperatures rather than at high temperatures, that is, some require cooling during use. Since the above-described photomultiplier also reduces noise by cooling, the use of the photomultiplier at a high temperature increases the noise, and a good analysis result cannot be expected. In addition, as the temperature control target (for example, the spectroscopic unit) increases, the amount of heat required to reach the set temperature from room temperature also increases, and it takes time to move that much heat. When it is set as the double thermostat like patent document 1, the temperature of the 1st thermostat (outside) is higher than room temperature, and the temperature of the 2nd thermostat (inside) is higher than the temperature of the 1st thermostat (outside). The temperature rises. In order to thermally isolate the second temperature chamber from the ambient temperature, that is, to mitigate the influence of changes in room temperature, the temperature of the first temperature chamber needs to be set to be considerably higher than room temperature. The temperature inside the second thermostatic chamber is a temperature far from room temperature. In addition, by repeating the operation / stop of the analytical instrument, the inside of the second thermostatic chamber is exposed to a desired set temperature when the analysis is performed, and to the room temperature when the analysis is not performed. This will cause the parts to deteriorate. The heat cycle has a great influence on the resin packing, adhesive, etc., and causes a failure of the analytical instrument.

  The present invention has been made in view of the above problems, and in order to thermally isolate the detection element from the environmental temperature, the temperature inside the thermostat inside is kept away from the room temperature while being a thermostat having a double structure. Is. That is, the invention of the present application is provided with a first thermostatic chamber that is provided with a first temperature control mechanism and controls the temperature at a first set temperature, and is disposed in the first thermostatic chamber, In the thermostat bath having a double structure composed of a second thermostat bath that controls the temperature at the second set temperature, the first set temperature is higher than the second set temperature and the temperature of the environment in which the thermostat bath is installed. Is also set high.

  [Operation] By applying the configuration of the thermostatic chamber according to the present invention, the temperature in the second thermostatic chamber can be set at a temperature close to room temperature (environmental temperature). The temperature of the first thermostat that thermally isolates the second thermostat from the ambient temperature is set higher than the ambient temperature.

  Further, the thermostatic chamber includes a Peltier element as a second temperature control mechanism, wherein one surface of the Peltier element faces the inside of the second thermostatic bath and the other surface faces the outside of the second thermostatic bath. .

  [Operation] By adopting a Peltier element, it becomes possible to reverse the heat transfer direction and switch between heating and cooling only by switching the applied voltage between forward and reverse.

  In the thermostatic chamber of the present invention, in the thermostatic chamber control method in which the Peltier element is applied to the temperature control mechanism, the Peltier element is in the second state until the temperature in the second thermostatic chamber reaches the second set temperature. A voltage is applied so as to heat the thermostatic chamber side.

  [Operation] With this control method, the Peltier element is reverse to the operation at the second set temperature when the temperature of the second thermostatic chamber is equal to or lower than the second set temperature after the operation starts. Conducts heat conduction (heating).

  The volume of the second (inner) thermostat is changed from the inner volume of the first (outer) thermostat by setting the thermostat to a double structure and setting the second (inner) thermostat to a temperature close to room temperature. The space portion minus the target becomes the main temperature control target by the first thermostatic bath, and the amount of heat necessary to reach the set temperature can be reduced. The temperature in the second thermostatic chamber becomes constant at a temperature close to the environmental temperature that was set before the operation of the analytical instrument was started (during stoppage). Can be obtained. Also, when the analytical instrument is used, the temperature becomes constant at a temperature close to the environmental temperature, so that the influence of the heat cycle is reduced, and the life of the components disposed in the second thermostatic chamber is extended. After the temperature control is started, while the space temperature in the second thermostat is lower than the second set temperature, the flow of heat of the Peltier element is reversed, so the arrival time to the set temperature of the second thermostat, that is, After the operation of the analytical instrument is started, the time until reaching the temperature condition for obtaining a suitable analysis result is shortened.

It is the schematic of the thermostat which concerns on this invention. It is a figure which shows the flow of the heat until constant temperature of the thermostat which concerns on this invention. It is the schematic of the conventional single temperature oven. It is the schematic of the conventional thermostat of a double structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Spectroscope 10, 30 ... 1st thermostat 11, 21, 31, 41, 51 ... Heater 12, 22 ... Fan 13, 23, 33, 43, 53 ... Temperature Sensors 15a, b ... Control units 20, 40 ... Second thermostatic bath 35 ... Pipe 36 ... Detection unit

Hereinafter, the present invention will be described in detail with reference to the drawings, taking a spectrophotometer as an example. FIG. 1 is a schematic view of a thermostatic chamber according to the present invention. The first thermostat 10 is covered with a heat insulating material (not shown), and includes a heater 11 for heating and a fan 12 that blows air to the heater 11 and circulates air in the housing (arrow A1). The inside of the first thermostat 10 is warmed. The temperature inside the first thermostat 10 is measured by the temperature sensor 13, and the controller 15a turns on the heater 11 so that the first set temperature (a temperature sufficiently higher than room temperature, for example, 40 ° C.) is set. / OFF control is appropriately performed. Thus, the space temperature inside the first thermostat 10 is maintained at the first set temperature.
Most of the surface of the second thermostatic chamber 20 is covered with a heat insulating material (not shown), and is enclosed in the first thermostatic chamber 10. The space in the first thermostatic bath 10 and the space in the second thermostatic bath 20 are not completely insulated, and some heat conduction through the heat insulating material covering the second thermostatic bath (arrow A4) And the space inside the second thermostatic bath 20 is heated. The 2nd thermostat 20 is provided with the Peltier device 21 as a means for radiating the heat of the inside to the exterior. The Peltier element is an element in which heat is transferred from one surface (cooling surface) to the opposite surface (heat radiation surface) when a voltage is applied.

  The Peltier element 21 is set so that when a positive voltage is applied, the inside of the second thermostatic chamber 20 is a cooling surface and the outside of the second thermostatic bath 20 is a heat dissipation surface, and each surface is exposed to each space. Thus, it arrange | positions on the wall surface of a 2nd thermostat. By applying a positive voltage to the Peltier element 21, the heat inside the second thermostat 20 is radiated to the outside of the second thermostat 20 (arrow A3). The air inside the second thermostat 20 is circulated by the fan 22 (arrow A2), and the temperature inside the second thermostat 20 becomes substantially uniform. The temperature inside the second thermostatic chamber 20 is measured by the temperature sensor 23, and the control unit 15b controls the Peltier element 21 so that the second set temperature is set near room temperature (temperature close to room temperature, for example, 27 ° C.). The forward / reverse switching of the applied voltage and ON / OFF control are appropriately performed. Thus, the space inside the second thermostatic chamber 20 is maintained at the second set temperature. Note that the output of the temperature sensor 13 can be easily stabilized by disposing the Peltier element 21 at a position far from the heater 11.

The internal space of the first thermostat 10 is slightly heated by the heat radiation (arrow A3) to the outside of the second thermostat 20 by the Peltier element 21. However, since the amount of heat given to the space in the first thermostat 10 is adjusted by the ON / OFF control of the heater 11 and the total amount of heat becomes constant, the temperature of the space in the first thermostat 10 is 1 set temperature is maintained. In addition, heat transfer efficiency improves by providing the fin for heat radiation (heat absorption) in the Peltier device 21. FIG.
As described above, in the thermostatic chamber according to the present invention, in the state where the temperatures of the first thermostatic chamber 10 and the second thermostatic chamber 20 have reached the respective set temperatures, the first set temperature is the environmental temperature and the first temperature. The temperature is controlled to be constant at a temperature higher than the set temperature of 2. While the analytical instrument is stopped, that is, while the temperature of the thermostat is not controlled, the temperature of the space in the first thermostat 10 and the temperature of the space in the second thermostat 20 equal to the environmental temperature are the shortest. Next, a control method for reaching the first set temperature and the second set temperature in time will be described. Actually, since there is a wall of the casing of each thermostat or a heat insulating material, there is a temperature gradient at the boundary, but it is simplified in FIG.

  FIG. 2 shows the temperature state and the operation of the apparatus in time series from the temperature at the start of operation of the apparatus until the set temperature is reached for the cross section taken along line B-B ′ in FIG. 1. The vertical axis of each graph indicates temperature, and the horizontal axis indicates the position along the line B-B ′. A broken line perpendicular to each horizontal axis indicates a tank boundary.

FIG. 2A shows a temperature state when the apparatus is stopped. When the apparatus is stopped for a long time, even in the space in the thermostatic chamber covered with the heat insulating material, the temperature becomes equal to the room temperature, the environmental temperature (T _RT ), the temperature (T ₁ ) of the _first thermostatic chamber 10, the second The temperatures (T ₂ ) of the constant temperature bath 20 are all equal.
The operation of the apparatus is started, and temperature control is started with the first set temperature as T _{OP, 1} (for example, 40 ° C.) and the second set temperature as T _{OP, 2} (for example, 27 degrees).

After the temperature control is started, the heater 11 is turned on for the first thermostat, and the voltage (reverse voltage) is applied to the Peltier element 21 so that the inside of the second thermostat 20 is the heat dissipation surface for the second thermostat. Is applied. The temperature of the first thermostat 10 is increased by the heater 11, and the heat is transferred to the inside of the second thermostat 20 by the Peltier element 21. After the rise in the space temperature of the first thermostat 10, the space inside the second thermostat 20 by heat transfer through the heat insulating material (arrow A 4) and by the heat dissipation operation of the Peltier element 21 (reverse direction of the arrow A 3). The temperature rises, and the space temperature of the second thermostatic chamber 20 slightly exceeds the _second set temperature T _{OP, 2} (FIG. 2B).

In this state, the operation of the Peltier element 21 due to the reverse voltage is stopped, and ON / OFF control with a positive voltage is started. Since the space temperature drops due to the operation of the Peltier element 21 with the positive voltage, the temperature reaches the _second set temperature T _{OP, 2} . Thereafter, ON / OFF control of applying a positive voltage to the Peltier element 21 is performed. The heater 11 is still ON. The heater 11 heats the first thermostat 10, transfers heat to the second thermostat 20 through the heat insulating material, and heats the second thermostat 20. Due to the heating by the heater 11, the temperature of the space in the first thermostat 10 slightly exceeds the _first set temperature T _{OP, 1} (FIG. 2 (c)).

In this state, the heater 11 is stopped and ON / OFF control is started. At the first time of this ON / OFF control, the heater is in a stopped state. Due to heat transfer from the inside to the outside of the first thermostat 10 (arrow A5), the space temperature in the first thermostat 10 drops and reaches the _first set temperature T _{OP, 1} ((FIG. 2 (D))). Thereafter, ON / OFF control of the heater 11 is performed based on the output of the temperature sensor 13.

  With the above control method, the second thermostatic chamber can be brought into the second set temperature state in the shortest time. Further time reduction is realized by reducing the volume of the first thermostat 10. If the volume of the first thermostat 10 is reduced, the amount of heat transfer can be reduced, and even if the thermal efficiency of the heater and Peltier element is the same, the time required to transfer the heat necessary to reach the target temperature is reached. Shorter.

  The above embodiment is merely an example of the present invention, and can be appropriately changed or modified within the scope of the gist of the present invention. For example, with regard to the control of the heater and Peltier element, if PWM (Pulse Width Modulation) control is performed instead of ON / OFF control, temperature control with higher accuracy becomes possible. It is also possible to change the rotation speed of the fan during temperature control. Although it is preferable in terms of heat transfer efficiency and power consumption that the temperature of the second thermostat is slightly higher than room temperature, it is also possible to control the temperature of the second thermostat to be slightly lower than room temperature. . In addition, although the case where the temperature of the first thermostat is higher than room temperature has been described as an example, the temperature of the first thermostat can be lower than room temperature. In this case, the same operation can be performed by replacing the heater as a cooler, heating as cooling, and arranging the applied voltage of the Peltier element forward / reversely or reversely. Although a heater has been described as an example of the heating means, the casing can be wrapped with a jacket, and hot water can be circulated in the jacket to provide the heating means. On the contrary, it can be set as a cooling means by distribute | circulating cold water in a jacket. Of course, what is applied to the thermostat according to the present invention is not limited to a spectrophotometer in which the spectroscopic unit is subject to temperature control, and can be applied to various uses as a thermostat. Obviously, these changes and modifications are also included in the present invention.

  It can be used as a thermostatic chamber for installing equipment that needs to keep the environmental temperature constant.

Claims (6)

A first thermostat having a first temperature control mechanism having at least a heating means and performing temperature control at a first set temperature;
A thermostat having a double structure including a second thermostat which is disposed inside the first thermostat and has a second temperature control mechanism having at least a cooling means and which controls the temperature at a second set temperature. In
The first set temperature is set higher than the second set temperature and the temperature of the environment in which the thermostat is installed. 2. The thermostat according to claim 1, wherein the second temperature control mechanism includes a Peltier element, wherein one surface of the Peltier element faces the inside of the second thermostat and the other surface faces the outside of the second thermostat. A thermostatic bath characterized by that. A first thermostat having a first temperature control mechanism having at least a heating means and performing temperature control at a first set temperature;
A second thermostatic chamber disposed in the first thermostatic chamber, including a second temperature control mechanism having a Peltier element as a cooling means, and temperature-controlled at a second set temperature;
In the constant temperature bath control method in which the first set temperature is set higher than the second set temperature and the temperature of the environment in which the constant temperature bath is installed,
A control method, wherein a voltage is applied so that the Peltier element heats the inside of the second thermostat until the temperature in the second thermostat reaches a second set temperature. A first thermostatic chamber having a first temperature control mechanism having at least a cooling means and performing temperature control at a first set temperature;
A thermostat having a double structure including a second thermostat which is disposed inside the first thermostat and has a second temperature control mechanism having at least a heating means and which controls the temperature at a second set temperature. In
The first set temperature is set lower than the second set temperature and the temperature of the environment in which the thermostat is installed. 5. The thermostat according to claim 4, wherein the second temperature control mechanism includes a Peltier element, wherein one surface of the Peltier element faces the inside of the second thermostat and the other surface faces the outside of the second thermostat. A thermostatic bath characterized by that. A first thermostatic chamber having a first temperature control mechanism having at least a cooling means and performing temperature control at a first set temperature;
A second thermostatic chamber disposed in the first thermostatic chamber, comprising a second temperature control mechanism having a Peltier element as a heating means, and temperature-controlled at a second set temperature;
In the constant temperature bath control method in which the first set temperature is set lower than the second set temperature and the temperature of the environment in which the constant temperature bath is installed,
A control method, wherein a voltage is applied so that the Peltier element cools the inside of the second thermostat until the temperature in the second thermostat reaches a second set temperature.

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