JPH0642741U - Constant temperature box - Google Patents

Abstract

(57) [Abstract] [Purpose] The object of the present invention is to improve the measurement accuracy of the accommodated sensor by maintaining the internal temperature at a constant temperature for a long time even if the size is small. A vacuum double container 1 containing a sensor 4 has different melting points within an allowable deviation with respect to the predetermined temperature.
At least one heat storage material 2 of at least one type is stored.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a constant temperature box.

[0002]

[Prior art]

 In general, the atmospheric pressure sensor and the like have large changes in characteristics with respect to changes in the ambient temperature, so it is necessary to use them at a constant temperature. Therefore, a so-called constant temperature box in which water is contained in a vacuum double container (magic bottle) has been conventionally used. In this constant temperature box, the atmospheric pressure sensor and the like are accommodated from the opening, positioned in the substantially central portion, and used with the opening closed with a heat insulating material.

[0003]

[Problems to be solved by the device]

 However, even with the thermostatic box, it is impossible to maintain the inside of the box in a completely adiabatic state, so heat flows in and out due to changes in the ambient temperature. Therefore, when the capacity of the constant temperature box is small, the heat capacity is small, and therefore the fluctuation range of the internal temperature becomes large as indicated by the one-dot chain line with respect to the change of the outside air temperature shown by the solid line in FIG. It may deviate from the permissible deviation shown by. Conversely, if the capacity is increased, it is possible to suppress the temperature change within the allowable deviation and increase the sensor detection accuracy, as shown by the dashed line in Fig. 7, but on the other hand, the constant temperature box becomes larger. However, there are problems such as the need for a large installation space and the difficulty of manufacturing the vacuum double container. The present invention has been made in view of the above problems, and an object thereof is to provide a thermostatic box that is small in size and can improve the detection accuracy of a sensor.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention accommodates a heat-retaining article such as a sensor and chemicals in a vacuum double container, which has a characteristic of being easily affected by ambient temperature change, and maintains the inside at a predetermined temperature. In the constant temperature box, at least two kinds of heat storage materials having different melting points within the allowable deviation with respect to the predetermined temperature are contained in the vacuum double container and housed.

Examples of the heat storage material include paraffins such as octadecane, triacontane, and heptacontane, organic substances such as caprylic acid, capric acid, myristic acid, palmitic acid, and naphthalene, KF · 4H ₂ O, Na ₂ SO ₄ · 10H ₂ Inorganic substances such as O, Ni (NO ₃ ) ₂・ 6H ₂ O, NaOH ・ H ₂ O, MgCl ₂・ 6H ₂ O or propionamide (25wt%) + palmitic acid (75wt%), Mg (NO ₃ ) ₂・6H ₂ O (53mol%) + MgCl ₂ · 6H ₂ O (47mol%), LiNO ₃ (27mol%) + NH ₄ NO ₃ (68mol%) + NH ₄ Cl (5mol%) eutectic To be done. Further, each heat storage material may be housed in a large number of capsules.

[0006]

[Action]

 According to the above configuration, heat flows in and out of the vacuum double container due to a change in ambient temperature. A heat storage material having a melting point within a permissible deviation with respect to a predetermined temperature changes its state from solid to liquid or from liquid to solid depending on the heat input and output. During the change of state, the latent heat of the heat storage material is used and the temperature inside the vacuum double container does not change, so that the heat storage material plays a role of maintaining a constant internal temperature even if the amount is small. . Further, by accommodating each heat storage material in the capsule, heat storage materials of different types are uniformly mixed without causing a chemical reaction.

[0007]

【Example】

Next, an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the thermostatic box according to the present invention contains a vacuum double container (a thermos bottle) 1 in which a heat storage material 2 and water 3 are mixed and housed. The double container 1 is positioned at the center and the opening 1a is closed by a lid 5. The heat storage material 2 and the water 3 are stored at a predetermined temperature, preferably at an intermediate temperature T _MID between the maximum air temperature and the minimum air temperature of the day. As the heat storage material 2, a first heat storage material 2a and a second heat storage material 2b having different melting points within the allowable deviation with respect to the above-mentioned predetermined temperature are used. The melting point of the first heat storage material 2a is higher than the intermediate temperature T _MID , and the melting point of the second heat storage material 2b is low. Each heat storage material 2a, 2b is housed in a resin capsule, as shown in FIG.

When the constant temperature box is used outdoors and the outside air temperature is T _MID , heat does not flow in and out, the first heat storage material 2a is in a solid state, and the second heat storage material 2b is All are in liquid state. Here, when the outside air temperature rises, heat is transferred into the vacuum double container 1 and the temperatures of the two heat storage materials 2a, 2b gradually rise. When the internal temperature reaches the melting point of the first heat storage material 2a, the heat transmitted from the outside is stored in the first heat storage material 2a as latent heat. Therefore, during this period, the temperature in the vacuum double container 1 is maintained at the same temperature as the melting point of the first heat storage material 2 a.

When the outside air temperature drops from this state, the heat stored as latent heat in the first heat storage material 2a is transferred to the outside as described above, and the first heat storage material 2a becomes completely in a solid state. It is maintained at a constant temperature until Then, when the first heat storage material 2a is completely in the solid state, the temperature is lowered together with the second heat storage material 2b in the liquid state. After that, when the internal temperature reaches the melting point of the second heat storage material 2b, the latent heat stored in the second heat storage material 2b is radiated, and the temperature in the vacuum double container 1 during this time is the same as that of the second heat storage material 2b. Maintained at the same temperature as the melting point.

As described above, even when the temperature inside the vacuum double container 1 rises or falls, the latent heat maintains the temperature at a constant temperature while the state of the heat storage material 2 is being changed. Therefore, the atmospheric pressure sensor 4 can be properly used within a range in which the characteristics of the atmospheric pressure sensor 4 do not change. Moreover, the amount of heat that is stored as latent heat in the heat storage material 2 or is dissipated is much larger than in the case where a constant temperature state is maintained by sensible heat like the conventional water 3, so the capacity of the heat storage material 2 Can be kept small.

Although the heat storage material 2 is housed in the capsule for use in the above embodiment, it may be layered in the vertical direction as shown in FIG. 3, and the sensor may be centered as shown in FIG. May be layered in the radial direction. In these cases, a resin sheet or the like is interposed between the layers, or each layer is housed in a vinyl bag so that the heat storage materials 2 do not directly mix with each other to cause a chemical reaction. There is a need to.

The present inventors conducted the following comparative experiment to confirm the effect. (Conditions) As the vacuum double container 1, one in which a heat quantity of about 1 kcal / h is transmitted from the outside to the inside when the temperature difference between the inside and the outside is 35 to 40 ° C is used. Each of the constant temperature boxes I and II contained the following. Constant Temperature Box I Heat Storage Material Melting Point Latent Heat Specific Heat Capacity A 39 ° C 40cal / cm ³ 1 250cm ³ B 37 ° C 40cal / cm ³ 1 250cm ³ Water ─ ─ 1 500cm ³ Constant Temperature Box II Heat Storage Material Melting Point Latent Heat Specific Heat Capacity Water ─ ─ 1 1000 cm ³ Each of the heat storage materials A and B contained in a resin capsule having a small diameter (2 to 10 μm) was uniformly mixed in the vacuum double container 1.

(Experimental method) The ambient temperature of the constant temperature box was set to 40 ° C and the internal temperature was set to 40 ° C. The temperature change in the constant temperature box was measured. (Experimental results) Constant temperature box I Time elapsed (hours) 0 1 2 11 12 13 14 23 24 Internal temperature (℃) 40 39 39 39 38 37 37 37 36 Constant temperature box II Time elapsed (hours) 0 1 2 3 5 Internal temperature (℃) 40 39 38 37 35

As described above, since the constant temperature box II uses only the sensible heat of the contained water, the internal temperature decreases almost directly in proportion to the passage of time as shown in the graph of FIG. The time from 40 ° C. to 35 ° C. was 5 hours.

On the other hand, in the constant temperature box I, it takes one hour to decrease the internal temperature from 40 ° C. to 39 ° C., but since the melting point of the heat storage material A is 39 ° C., the heat storage material A is completely removed. During the 10 hours until the solidification, the heat quantity stored as latent heat in the heat storage material A was released and maintained at 39 ° C. After that, until the internal temperature reaches 37 ° C., which is the same temperature as the melting point of the heat storage material B, the temperature decreases at a rate of 1 ° C. for 1 hour, and from the time when the temperature reaches 37 ° C. until the heat storage material B solidifies. The heat amount stored as latent heat in the heat storage material B was released for 10 hours, so that the temperature was maintained at 37 ° C.

Therefore, it takes only 5 hours for the internal temperature of the constant temperature box II to decrease by 5 ° C., whereas it takes 24 hours for the constant temperature box I to decrease by 4 ° C., which is a sufficient effect for maintaining the internal temperature. It turned out to exert. Further, from this result, if it is intended to obtain the same effect as the constant temperature box II with the constant temperature box I, it can be easily inferred that the capacity for inserting the heat storage material 2 can be reduced to 1/8.

Although the atmospheric pressure sensor 4 is housed in the vacuum double container 1 in the above-described embodiment, another sensor having a characteristic that the ambient temperature change is easily affected may be used. In addition, medicines such as collagen and suppositories may be stored. When these chemicals are shipped by air, the ambient temperature fluctuates significantly due to changes in altitude (normally the cargo compartment is not air-conditioned), but as mentioned above, the temperature inside the vacuum double container 1 is maintained at a constant temperature. Therefore, even if it is a suppository that melts at about 35 ° C, it does not have a tendency.

[0018]

[Effect of device]

 As is apparent from the above description, the constant temperature box according to the present invention uses the latent heat of the heat storage material to keep the internal temperature within the allowable deviation with respect to the predetermined temperature. It requires a smaller amount than the one used and can be miniaturized. Moreover, since a plurality of types of heat storage materials are stored, it is necessary to select one with a melting point that is higher or lower than the predetermined temperature, regardless of whether the outside air temperature rises or falls. The latent heat of the heat storage material can be used, and the internal temperature can be reliably suppressed within a permissible deviation from the predetermined temperature. Further, since each heat storage material is housed in the resin capsule, it is possible to uniformly mix them without causing a chemical reaction, and it is possible to maintain the internal temperature evenly. .

[Brief description of drawings]

FIG. 1 is a sectional view of a constant temperature box according to the present embodiment.

FIG. 2 is an enlarged sectional view of a heat storage material housed in the constant temperature box of FIG.

FIG. 3 is a sectional view of a constant temperature box according to another embodiment.

FIG. 4 is a sectional view of a constant temperature box according to still another embodiment.

FIG. 5 is a graph showing experimental results.

FIG. 6 is a graph showing changes in temperature and outside air temperature in a small-sized constant temperature box according to a conventional example.

FIG. 7 is a graph showing a change in temperature inside a large-sized constant temperature box and an outside air temperature according to a conventional example.

[Explanation of symbols]

1 ... Vacuum double container, 2, 2a, 2b ... Heat storage material, 3 ... Water,
4. Atmospheric pressure sensor (sensor).

Claims (2)

[Scope of utility model registration request] 1. A constant temperature box in which a temperature-retaining article such as a sensor and chemicals having a characteristic of being easily affected by ambient temperature change is housed in a vacuum double container, and the inside of which is maintained at a predetermined temperature, A constant temperature box, characterized in that at least two types of heat storage materials having different melting points within the allowable deviation with respect to the predetermined temperature are contained in a vacuum double container. 2. The constant temperature box according to claim 1, wherein each of the heat storage materials is housed in a large number of capsules.