JP2901887B2 - Dew condensation prevention device for the see-through part of environmental test equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing dew condensation on a see-through portion of an environmental test apparatus.

[0002]

2. Description of the Related Art In an environmental test apparatus, an observation window or a glass door is usually provided on a door for observing a test room. However, dew condensation occurs on the surface of the glass depending on the temperature and humidity conditions of the operated test room, and various techniques have been conventionally used to prevent this.

[0003] Among them, there is an environmental test apparatus using, for example, air-sealed pair glass. However, in an apparatus using only a pair of glass, dew condensation in the case of performing a low-temperature test at −10 ° C. or less is inevitable. In addition, there is a device in which vacuum insulation is provided between the pair of glasses. However, this device increases the manufacturing cost and also has heat conduction from the peripheral portion.

There is also an environmental test apparatus in which a window is heated using glass containing a heating element. However, when a conductive film is laid as a heating element in glass, there is a problem that the cost is similarly increased and the internal visibility is deteriorated by the conductive film. At the time of low-temperature operation, the amount of heat for heating the glass increases, and the heat directly enters the test chamber, which significantly reduces the thermal efficiency of the environmental test apparatus.

[0005] Further, there is a device in which a desiccant such as silica gel is sealed between opposite glass, a device in which nitrogen is sealed, and a device in which a heat shielding film is adhered. There is also a problem in that there is no significant effect, and replacement or reproduction must be performed in a certain period.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art and provides a test chamber in a low temperature condition or a high temperature and high humidity condition.
Under the conditions , the heat load that enters the test room is small,
An object of the present invention is to provide an apparatus for preventing dew condensation of a see-through portion of an environmental test apparatus, which is capable of completely preventing dew condensation with good transparency, low cost, and a simple configuration.

[0007]

According to a first aspect of the present invention, a dew condensation preventing device for a see-through portion of an environmental test apparatus is provided at an opening of a test room air-conditioned by an air circulation system. Outer and inner transparent members, which are provided so as to face each other so as to form one space , and which have transparency from the outside to the test chamber, and the air of the air circulation system. Ventilation means for guiding the air into the space and returning the air in the space to the air circulation system, the introduction-side switching means and discharge for interrupting conduction with the air circulation system and enabling introduction of outside air and discharge to outside air It is characterized by having ventilation means provided with side switching means, and heating means for heating the air on the upstream side so that the temperature of the air in the space becomes a predetermined temperature or higher.

[0008]

According to the first aspect of the present invention, since the ventilation means is provided, the air in the air circulation system for air conditioning can be supplied to the space between the inside and outside see-through members and returned to the air circulation system again. . And since the heating means which heats the air of the upstream so that the temperature in a space part becomes more than predetermined temperature is provided, at the time of low-temperature operation, the predetermined temperature is set based on the heat transfer coefficient of the outer transparent member. By taking the temperature difference between the inside and the outside into consideration so that the outside temperature of the outside see-through member does not fall below the dew point temperature of the outside world, dew condensation on the see-through member is completely prevented.

That is, first, the air in the space is heated and has a temperature higher than the temperature of the circulating air system.
Since the test room is not cooled, there is no dew condensation on the test room side of the inner see-through member, and since the air in the space is the same as the air circulating in the test room, the inside and outside see-through members are on the space side. However, no condensation occurs. Further, since the outside of the outer member does not become lower than the dew point temperature of the outside world, no dew condensation occurs at this position. Therefore, dew condensation on all surfaces of the see-through member is prevented.

[0010] During such low-temperature operation, the temperature of the space side is greatly reduced because the inside transparent member is cooled by the low temperature of the test room. Therefore, if the outside air is heated instead of heating the circulating air in the tank as in the present invention, the dew point of the outside air is higher than that of the circulating air, so that the air in the space is heated to a considerably higher temperature than the outside air temperature. Unless heating is performed to the extent necessary, it is not possible to prevent dew condensation on the space side of the inner see-through member. When the temperature of the space is increased in this way, the heat that enters the test chamber increases, and the temperature turbulence in the test chamber increases. According to the present invention, such intrusion of heat into the test chamber is reduced. On the other hand, in the present invention, air in the circulating air system is taken out, but since the same air is returned to the circulating air system,
Absolute humidity does not change. Therefore, the sensible heat load only increases in the circulating air system, and the heat load on the cooling device is extremely small.

Further, the dew condensation preventing device is constituted by an inside and outside see-through member having a space, a ventilation means and a heating means, so that it is not necessary to perform costly vacuum insulation, adoption of a glass with a conductive film, enclosing a desiccant, etc. Therefore, the cost is reduced with a simple structure. The temperature increasing means may be provided in the ventilation means, or may be provided in the space at a position where the visibility inside is not hindered.

Furthermore, since the ventilation means has the introduction-side switching means and the discharge-side switching means, the conduction with the circulating air system is cut off, the outside air is sucked, heated and sent to the space, and the air is discharged to the outside. be able to. As a result, when the test chamber is operated at high temperature and high humidity, dew condensation on the space side of the outer see-through member can be effectively prevented by heating the outside air having a relative humidity smaller than the air in the circulating air system.

[0013]

DETAILED DESCRIPTION FIG. 1 shows the overall structure of the anti-condensation device of the perspective of environmental testing apparatus of the embodiment, FIG. 3 is the outside air introduction and discharge
The configuration of the part is shown. Note that the portion shown in FIG.
Are omitted. The components in FIG. 3 will be described later.
This will be described with reference to FIG. The apparatus is provided at an opening 3 of a test room 2 air-conditioned by a main circulation system 1 which is an air circulation system. Protective glass 7 and laminated glass 8 as outer and inner see-through members having a see-through property into the test chamber 2 from the air, and ventilation of the main circulation system 1 to the space portion 5 and returning the air to the main circulation system 1 As means, the air supply pipe system 9 forming the bypass circulation system, the air return pipe system 10 and the air pump 11 provided in the air supply pipe system 9 of the pipe system, and the temperature of the air in the space 5 is equal to or higher than a predetermined temperature. And a dew condensation preventing heater 12 as a heating means for heating the air on the upstream side.

The environmental test apparatus according to the embodiment equipped with such a dew condensation preventing apparatus is a table type environmental test apparatus, in which a vertical structure 20 and a bottom structure 21 are connected by a pedestal section 22, and a heat insulating wall is provided. The main body 24 surrounded by 23 is mounted on the gantry 22 and connected to the vertical structure 20.

The main body 24 includes a test room 2 in which a work W such as an electric product is placed as an object to be tested and is air-conditioned, an air-conditioning room 25 adjacent thereto, and air circulation between the test room and the air-conditioning room. And ducts 26 and 27 arranged to form the main circulation system 1 to be formed. The opening 3 of the test chamber 2 is provided with a door 28 movably mounted in the direction of arrow A along the opening surface. The door 28 is formed by attaching the protective glass 7 and the laminated glass 8 to the frame member 4. In the air-conditioning room 25, a fan 30 rotated by a motor 29 and a cooler 3 for cooling circulating air are provided.
1, a heater 32 for heating, a pre-cooling pipe 33 and the like are provided. In the gantry 22, electric and mechanical equipment including a refrigerator and the like (not shown) is housed. Reference numeral 34 denotes a rotating body that supports the environmental test apparatus so that it can be transported.

In FIG. 1, the ventilation means is an air pump 1
However, when the pressure difference of the fan 30 is sufficiently large, the air supply pipe system 9 is opened to the discharge side of the fan 30 as shown by a two-dot chain line in FIG. It is also possible to omit the air pump 11 by utilizing the differential pressure between the pressure and the suction pressure.

The above-described environmental test apparatus is operated as follows. When the work W is put into the test room 2 and the door 28 is closed, various devices in the environmental test apparatus are operated, and the inside of the test room 2 is air-conditioned. That is, the refrigerator (not shown) in the machine room 22 is operated, and the refrigerant is sent to the pre-cooling pipe 33 for dehumidification and sent to the cooler 31 which is an evaporator.
Is turned on, and the target temperature inside the test chamber 2, for example, -4
Air is circulated to maintain a low temperature of 0 ° C. At the same time, the pump 11 is operated to turn on the dew condensation prevention heater 12, and the supply air of the bypass circulation system is turned on so that the temperature of the air in the space 5 of the door glass becomes, for example, about 25 ° C. as a predetermined temperature. Heat.

FIG. 2 shows an example of the approximate temperature distribution of the door glass portion during the low-temperature operation as described above. For example, if the outside air has a temperature of 30 ° C. and a dew point of 24 ° C. (relative humidity of about 70%), it depends on the material and design conditions of the glass and other various conditions due to a normal heat transfer phenomenon. Temperature distribution is formed. As a result, the temperature of the outer surface 7a of the decorative glass 7 becomes higher than the dew point temperature of the outside world, and no dew condensation occurs on that surface. If the external conditions are different, the heating temperature of the air in the bypass circulation system is changed as necessary. On the surface 7b of the decorative glass on the space portion 5 side, the air introduced into the space portion is the same air as the main circulation system and has a dew point of −40 ° C. or less (for example, −42 ° C.). There is no fear.

Since the temperature difference between the space 5 and the test chamber 2 is large on the laminated glass 8 side, the amount of heat passing through the laminated glass 7 is greater than on the decorative glass 7 side. As a result, the temperature of the surface 8a of the laminated glass 8 on the side of the space 5 becomes lower. Accordingly, if outside air having a high humidity is introduced into the space, the dew point is high, so that condensation on the surface 8a cannot be prevented unless the outside air is heated to a temperature considerably higher than the outside air temperature. By doing so, the heat that enters the test chamber 2 increases, the internal temperature turbulence increases, and the performance of the test chamber decreases. Laminated glass 8
In the case where is made of glass containing a heating element, the heat is directly transmitted to the test room side, and a large heat load similarly enters the test room. If the air in the main circulating system of the test chamber is heated and introduced as in the present invention, the dew point is -42 ° C. Therefore, even if the temperature is lower than the outside air temperature, there is a possibility of dew condensation on the surface 8a. Not at all. Therefore, the heat entering the test room is reduced,
Its performance can be improved. Since the temperature of the surface 8b of the laminated glass 8 on the test room side is higher than the temperature in the test room, no dew condensation occurs here.

As described above, according to the present invention, even during a low-temperature operation where it is difficult to prevent dew condensation, dew condensation on the door glass can be completely prevented without providing a heat transfer film or the like. Therefore,
The visibility between the inside and outside becomes very good.

In order to satisfy the above conditions, the dew condensation preventing heater 12 converts the air at -40 ° C. to + 25 ° C.
Although the heat must be heated to a certain degree, the amount of heat is not large because the air flow rate in the bypass circulation system is small. Therefore, the heater may be small. On the other hand, in the present invention, since the air introduced into the space 5 is returned to the main circulation system 1 again, the amount of heat heated by the heater is brought into the circulation air system 1. However, since the dew point of this air is −42 ° C., it is not dehumidified even when returned to the main circulation system, and only the sensible heat load increases in the main circulation system.
On the other hand, if the air discharged from the space 5 is released to the outside without being recovered, the pressure balance in the tank may be reduced.
It is necessary to introduce outside air into the main circulation system. However, since the outside air has a high dew point, when it is put into a tank, it is necessary to remove not only the sensible heat load but also the latent heat load until the dew point becomes -42 ° C. Therefore, by forming a bypass circulation system for preventing dew condensation as in the present invention, it is possible to suppress a decrease in thermal efficiency as an environmental test device.

Next, referring to FIG .
explain about. The piping systems 9 and 10 serve as introduction-side switching means and discharge-side switching means for interrupting conduction with the main circulation system 1 and enabling introduction and discharge of outside air to the upstream side of the air pump 11 and the space 5. An outside air suction pipe 40 and an outside air discharge pipe 41 and valves 42, 43, 44 and 45 are provided on the downstream side. The valves 42 and 43 and the valves 44 and 45 may be integrated three-way switching valves. With such a device, only the outside air can be sucked and introduced into the space 5, and can be discharged to the outside air.

The environmental test apparatus can be used under low temperature conditions,
Used under various conditions such as high temperature and high humidity. When used under high-temperature and high-humidity conditions, the air in the main circulation system 1 may be heated to a higher temperature and introduced into the space 5 by the apparatus shown in FIG. The use of the device makes it possible to prevent dew condensation at lower temperatures. For example, when the inside of the test chamber 2 is used under high-temperature and high-humidity conditions such as 80 ° C. and a dew point of 75 ° C., the temperature of the space 5 becomes 80 ° C.
The outside air (for example, 20 ° C., dew point 10 ° C. (relative humidity 52.5 ° C.)
%) Is heated and introduced into the space portion 5, and then a dew condensation preventing operation is performed to release it to the atmosphere.

FIG. 4 shows an example of a schematic temperature distribution of a door glass portion during a high-temperature and high-humidity operation. Since the temperature of the outer surface 7a of the decorative glass 7 rises, there is no possibility of dew condensation. Although the inner surface 7b is cooled at a low temperature of the outside air, since the heated outside air is introduced into the inside 7b, its dew point is the same as that of the outside air.
Again, no condensation occurs. Similarly, face 8 of laminated glass 8
Also in a, there is no possibility of dew condensation. Further, since the temperature of the space 5 is the same as the temperature of the test room 2, the surface 8b of the laminated glass 8 on the test room 2 side is not cooled, and dew condensation on this surface is also prevented. Therefore, dew condensation on the door glass portion is completely prevented.

When the bypass circulating air system is used for such a high-temperature and high-humidity operation, since the dew point of the air introduced into the space 5 is high, the face 7b of the decorative glass cooled by the outside air is used.
In order to prevent the dew condensation, the temperature in the space 5 must be increased. However, by using outside air as in the present embodiment, dew can be effectively prevented without increasing the temperature in the space.

In the apparatus as described above, in order to uniformly supply heated air into the space 5, an air supply header 50 and an exhaust header 51 each having a hole 50a, 51a are provided as shown in FIG. You may. Although the dew condensation prevention heater 12 is provided in the bypass piping system in the above description, it may be provided in the glass space 5, for example, on the downstream side of the air supply header 50 in FIG. 5. Further, in FIG. 1, the bypass circulation system is introduced from the outlet portion of the cooler 31 in the main circulation system 1. However, the bypass circulation system is introduced to another portion, for example, the air is taken in from the exit portion of the heater 32 and returned to the entrance portion of the cooler 31. May be. Further, the air pump 11 is connected to the air return pipe system 1.
It can also be arranged on the 0 side.

In the above embodiment, the case where the door 28 is entirely a glass window has been described.
The present invention can also be applied to a device in which a member is made of a heat insulating member and a window is provided in a part thereof. Although the embodiment in which the glass on the side of the test chamber 2 is a laminated glass has been described, it is needless to say that this may be a single glass. Further, the transparent member is not limited to glass, but may be plastic or the like.

[0028]

As described above, according to the present invention, according to the first aspect of the present invention, the air in the air circulating system of the test room is heated and introduced into the space between the inside and outside transparent members, and the air is circulated again. The dew condensation prevention device is designed to return to the system, so the low-cost and simple structure prevents condensation on the see-through member without causing excessive heat load to enter the test room or greatly reducing the thermal efficiency as an environmental test device. Can be completely prevented, and extremely good transparency can be obtained. In addition to the above, since introduction, heating and discharge of outside air are enabled, dew condensation can be effectively prevented without increasing the temperature of the space during high-temperature and high-humidity operation.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a device for preventing dew condensation on a see-through portion of an environmental test apparatus according to an embodiment.

FIG. 2 is an explanatory diagram showing a temperature distribution of a glass portion during a low-temperature operation in the above apparatus.

FIG. 3 is an explanatory view of a dew condensation preventing device for a see-through portion of an environmental test apparatus according to another embodiment.

FIG. 4 is an explanatory diagram showing a temperature distribution of a glass portion during a high-temperature and high-humidity operation of the apparatus.

FIG. 5 is an explanatory diagram in the case of providing an air supply / exhaust header in a space.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Main circulation system (air circulation system) 2 Test chamber 3 Opening 4 Frame member 5 Space part 7 Decorative glass (outer see-through member) 8 Laminated glass (inner see-through member) 9 Air supply pipe (ventilation means) 10 Air return pipe ( Ventilation means) 11 Air pump (Ventilation means) 12 Dew condensation prevention heater (Heating means) 40 Outside air suction pipe (Induction side switching means) 41 Outside air discharge pipe (Discharge side switching means) 42, 43 Valve (Introduction side switching means) 44 , 45 valves (introduction switching means)

Claims (1)

(57) [Claims] From 1. A external disposed opposite to form one <br/> space an outer and inner transparent member provided at an opening portion of the test chamber which is conditioned by an air circulation system Outer and inner see-through members having transparency into the test chamber, and ventilation means for guiding the air of the air circulation system to the space and returning the air of the space to the air circulation system, wherein the air circulation system Ventilation means provided with introduction-side switching means and discharge-side switching means for interrupting conduction of air and allowing introduction and discharge to the outside air, and upstream thereof so that the temperature of the air in the space becomes a predetermined temperature or higher. And a heating means for heating the side air.