Backgroud Art Generally, in undesirable factors against the exhibits on display, there are harmful rays of illuminator, humid air and temperature change, pollutants contained within atmosphere such as floating dusts, sulfide, nitrite, oxygen, carbon monoxide, carbon dioxide, ozone, sodium chloride, and ammonia, mold, microbe, insects, mice and the like. Among them, more than one are interacted one another and affect the exhibit, thus deteriorating it.

Therefore, in order to keep and preserve the exhibit in its optimum state, various methods separating the exhibit from said undesirable factors have been proposed, and they have been performed by developing the showcase for displaying the exhibit. In prior art, there were two simple type as general forms of showcase to meet the purpose stated

above, one was the complete-closed type showcase with its whole body closed completely, the other was the semi-closed type showcase allowing indoor air properly dried to ventilate inside the showcase.

This complete-closed type of the showcase can effectively prevent the above-stated undesirable mold etc, from coming into therein, but it can't shut off the influence according to the changes of temperature and humidity occurred by rays of light at all. In this showcase, since the lighting apparatus keeps on local heating the inner air of showcase and raising temperature of the inner air therein, this causes to form the uniform temperature distribution through the upper and lower space in the showcase, which is harmful to the exhibit on display.

In addition, since the high temperature of the inner air in the showcase activates chemical reaction, Oxygen of inner air causes to promote the oxidation of the exhibit on display in the showcase. This high temperature also decreases the relative humidity of the inner air in the showcase, thus extracting the moisture from the exhibit, which may cause fatal damage to the exhibit.

Moreover, since the temperature in the showcase drops sharply when the lighting apparatus is turned off, this temperature change constricts the exhibit itself and deteriorats the exhibit gravely. That is, in this lower temperature, the relative humidity of the inner air in the showcase increases, and the moisture of the inner air is absorbed into the exhibit. In higher temperature, on the contrary, the relative humidity of the inner air decreases, and thus the moisture contained within the exhibit is extracted therefrom. The humidity coming in and out of the

exhibit also can fatally damage to the exhibit.

Generally, the material for adjusting humidity can be used for dehumidification or control of the humidity of the inner air in the showcase. However this material acts properly in the proper range of temperature, but at higher temperature, the material for adjusting humidity tends to lose adjusting ability thereof, thus allowing the moisture of the inner air to come in and out of the exhibit to deteriorate it. Therefore, this complete-closed type of the showcase, which leaves the change of the temperature out of account, is not suited to the preservation of the exhibit.

As the other type of showcase, there is a semi-clbsed type showcase that allows lower-temperature of the outer air to be induced into the showcase and higher-temperature of the inner air in the showcase to be discharged therefrom, thereby cooling the inner space of the showcase. This type of the showcase can prevent inner temperature of the showcase from rising to some extent, but there are problems that the relative humidity of the showcase depends on the change of humidity the outer air to be induced into the showcase, inner space of the showcase is always exposed to the risk of inflow of outer pollutants and the increase of mold, microbe and moth. Therefore, in this type showcase, there is required an air-conditioning system additionally.

In Conservation center in Metropolitan Museum of Art, N.Y.U.S.A, the new preservation system is employed for minimizing the influence of circumstances outside the showcase. this system comprises a central air-conditioning apparatus for controlling temperature and humidity of air and filtering air, a duct system for providing each showcase with filtered and conditioned air by said air-conditioning

apparatus, and a showcase for displaying the exhibit. The showcase has slits for ventilating at a certain portion and is provided with conditioned air through said duct system, at the same time, and discharges out the inner air through the slits, and keeps inner pressure of each showcase at somewhat higher level than that of the outside.

However, since this preservation system is a large mechanical plant, which has additional equipments for cleaning up supply-air and adjusting humidity and temperature of the air and duct system for providing each showcase with the conditioned air, it requires high-expense of its installation, operation and maintenance, occupies a large installation area, and has a problem that outer air (or indoor air) flows back into the showcase when the system is out of order and stopped by a power failure, and the system has.

Moreover, since the system is operated with the central concentrated way, in the case that it is necessary to separately adjust temperature and humidity of each showcase for allowing the exhibit in each showcase to be respectively kept in its optimum condition and in the case of displaying the exhibits in smaller place and home-displaying, it is not a suitable preservation system.

Disclosure of Invention It is therefore an object of the present invention to provide an apparatus for preserving the exhibit such as paint, picture, antique etc., which can effectively prevent the discolor, deformation, and damage of the exhibit on display by shutting off the harmful rays to the exhibit not to transmit and adjusting temperature and relative humidity

of inner air in the showcase efficiently.

It is another object of the present invention to provide an apparatus for preserving the exhibit, which has an excellent airtight property and effectively separates inner space of the showcase from outer pollutants, and which can stabilize inner atmosphere in the showcase so as to prevent chemical reaction between the exhibit and harmful air and prevent the increase of microbe.

It is other object of the present invention to provide an apparatus for preserving the exhibit, which can discharge the accumulated heat within the showcase effectively, and controls temperature and relative humidity of inner gas in the showcase automatically and uniformly, thus preventing the deterioration of the exhibit on display and the increase of microbe in the showcase.

It is other object of the present invention to provide an apparatus for preserving the exhibit, which can be constructed simply and less expensively.

In order to achieve the above-specified object, according to the present invention, there is provided an apparatus for preserving the exhibit comprising: a showcase, as a closed box-shaped, for receiving and displaying exhibit, which its inner space is divided into a front space and a rear space by a partition member have a plurality of circulation path through which inner gas circulates between said front space and said rear space; a lighting means arranged at upper side of said showcase for illuminating said front space of said showcase; a means for adjusting relative humidity contained within inner gas in said showcase; and a cooling means for the cooling the heat of said showcase, which includes an inlet port arranged at

lower portion of said showcase for introduce indoor air, a flow path formed at rear portion of said showcase for flowing upward, and a duct connected at upper portion of said showcase for discharging the heated indoor air by heat-exchange to the outside.

In order to accomplish the above objective, the present invention further provides An apparatus for preserving the exhibit comprising: an outer frame, as box-shaped body, having most of front and rear surfaces thereof opened and its projected portion extended by a certain distance from edge portion of front surface thereof inward of said front opening; an insert body inserted to inner space of said outer frame through said rear opening, which includes a front window, as a plate-shaped transparent member, arranged with its periphery portion abutted to said projected portion of said outer frame to close said front opening thereof, a rear plate member for close said rear opening of said outer frame, an inner frame, as box-shaped body, having most of front and rear surfaces thereof opened and arranged between said front window and said rear plate within said outer frame, and sealing members, respectively inserted between said front window and said inner frame and between said rear plate and said inner frame for keeping airtightness in a space defined by said front window, inner frame and rear plate; a means for adjusting relative humidity contained within inner gas in said closed space of said insert body, defined by said front window, inner frame and rear plate; and a plurality of spacers respectively arranged upper and lower portion of said rear surface of said outer frame for locating said outer fame with said rear surface thereof spaced out a certain interval from

a wall of building.

Brief Description of Drawings Other features in structure, operation and advantages of the present invention will become more apparent to those skilled in the art from the following descriptions when read in conjunction with the accompanying drawings, in which: Fig. 1 is a cross-sectional view showing an embodiment of an apparatus for preserving the exhibit according to the present invention; Fig. 2 is a perspective view of Fig. 1, with a part of portion cut off partially; Fig. 3 is a cross-sectional view showing another embodiment of an apparatus for preserving the type exhibit according to the present invention; Fig. 4 is a perspective view of Fig.3, with a part of portion cut off partially; and Fig. 5 is a cross-sectional view showing other embodiment of an apparatus for preserving the type exhibit according to the present invention, with an electro cooling system arranged on the radiating plate of the showcase.

Best Mode for Carrying Out the Invention Hereinafter, the embodiments of an apparatus for preserving the voluminous exhibit according to the present invention will be described in detail, referring to the drawings.

Fig. 1 shows the first embodiment of the present invention in which the voluminous exhibit 33 can be on display. Fig. 2 perspectively shows the structural elements of the Fig.1 in more detail.

Referring to Fig. 1 and Fig. 2, the apparatus for preserving the exhibit in this embodiment is largely divided into: a showcase, as an airtight-box type, in which the exhibit is received and on play; an illuminator for lighting up the exhibit; and a cooling system for circulating indoor air (that is, the air outside showcase) and thus cooling the showcase.

The showcase comprises a front side window 34; both side window (not shown); a radiating plate 45 (that is, a rear plate or wall of the showcase) for transmitting the inner heat of the showcase to the indoor air circulating by the cooling system and for adjusting the inner temperature of the showcase; a lighting window 38 for transmitting the rays of the illuminator 36 to the inner space of the showcase; a partition plate 42 for dividing the inner space of the showcase into a front side space 35 and a rear side space 44; a means 43 for adjusting the relative humidity of inner gas in the showcase; a plurality of valves 31 and 31' for providing the inner space of the showcase with inert gas, at the same time, and discharging the air out of the showcase; and sealing means, such as gasket, silicon for caulking, which are used for keeping the airtightness of the showcase.

The showcase is located spacing out a certain distance from walls 39, 47 and 50, this creates a flowing path 46 of indoor air between walls 39, 47 and 50 and an upper surface 40, a rear surface (that is, the radiating plate or rear plate) 45 and a bottom surface 48 of the showcase.

The front side window 34 and both side windows, each forming a front portion and both side portions of the showcase, are made of transparent glass or synthetic resin

so as to the exhibit on display can be seen from the outside.

The partition plate 42 for dividing the inner space of the showcase into two spaces 35 and 44 has a plate-shaped horizontal portion 49 extending horizontally from is lower end and installed within the showcase with spaced out a certain interval from rear surface 45 and bottom surface 48 of the showcase, thus forming the rear side space 44. The exhibit is on display in the front side space 35 with seated on this horizontal portion 49 of the partition plate 49. An upper vent hole 41 is formed at the upper end portion of the plate 42 and a lower vent hole 32 is formed at the end portion of the horizontal portion 49, through which the inner gas circulates between a front side space 35 and a rear side space 44.

In the upper portion of the showcase, the illuminator 36 is installed and lights up the front side space 35 through the lighting window 38. The lighting window 38, made of the transparent plate-shaped member which can selectively exclude the rays having a particular wavelength, airtightly separates the front side space 35 from the space where the illuminator 36 occupies. The transparent member includes a film for reflecting infrared rays and a filter for shutting off ultraviolet rays, so it excludes ultraviolet and infrared rays emitting out from illuminator 36, on the contrary, transmits only visible rays into the front side space 35 of the showcase.

The film for reflecting infrared rays may be such a thing as a transparent conductive film, a dielectric multi-layer film, a metal-dielectric compound film and the like. The filter for shutting off ultraviolet rays may be

such a thing as an acryl plate having a good absorbency of ultraviolet rays, polycarbonate, a ultraviolet-extinction plastic thin film, a laminated glass with ultraviolet-extinction plastic, a glass containing oxidized cesium and the like.

The rear wall (that is, rear plate) 45 the showcase acts as radiating plate for absorbing the heat from the gas passing through the rear side space 44 and transmitting the absorbed heat to the indoor air circulating through the flowing path 46 of the cooling system. The radiation plate (or rear wall or plate of the showcase) 45 is made of the metal having a good thermal conduction property such as copper, aluminum and the like, if necessary, radiating fins may be arranged on the outer surface of the radiating plate 45 to increase the heat radiation amount.

The means 43 for adjusting the relative humidity is located on the rear surface of the partition plate 42 so as to increase the chance of contacting the gas passing through the rear side space 44. In the present invention, the means 43 is prepared to having an proper ability of adjusting humidity in advance, employing such materials as silica gel, zeolite and the like which have a better hygroscopic property and humid-discharge property than those of the exhibit and have been developed to have a great ratio of water content to weight.

A plurality of valves 30 and 31' (two in the drawings), for example check valves, consists of one for injecting inert gas such as Helium, Argon, Neon and the like into the showcase and other for extracting the old air from the showcase. They are respectively installed at places where they are hardly seen from the outside, that is, as shown at

the upper portion of the rear surface 45 and the bottom surface 48 of the showcase. Here, the number of valves is not limited to that of valves stated above, several valves, more than two, may be employed according to the scale of the showcase. Therefore the inert gas can be injected into inner space of the showcase through one valve or more, while extracting the air out of the inner space thereof through other vale. In order for controlling the relative humidity of the inert gas injected into the showcase, some distilled water may be also provided through these valves.

Next, the cooling system comprises inlet 30 for introducing indoor air into the lower portion of the showcase; the flowing path 46, formed between walls 39, 47 and 50 and the showcase, through which the introduced indoor air 52 flows upward; the duct system 51 connected to the upper portion of the showcase.

Therefore, the indoor air is introduced through an air inlet 30 which is located at lower potion of the front surface of the showcase, and passes through the flowing path 46 formed between the walls and the showcase, at this time, the indoor air deprive the showcase of the heat through the radiating plate 45 and is heated, and then the heated indoor air more easily flows up and moves into the duct system 51.

The cooling efficiency through the radiating plate 45 depends on the flow rate and the temperature of the indoor air passing through the flowing path 46. This shows that the cooling efficiency of the showcase depends on the flow rate and the temperature of indoor air passing through the flowing path 46.

Here, it is desirable that the duct 51 is located next to the illuminator 36 installed at the upper portion of the

showcase so that the heat generated from the illuminator 36 can easily discharge into the duct 51 alcng with the heated indoor air.

Hereinafter, the operation of the first embodiment having the above construction will be described.

The inert gas is injected into the showcase through one valve or more, at the same time, the air within the showcase is extracted therefrom through other valve. Since the injected inert gas do not react on other elements and stabilizes the inner atmosphere within the showcase, it cause to prevent the increase of microbe inhabiting in the exhibit and the chemical change of the exhibit on display, for example, the oxidization of the metal exhibit.

Since the front side space 35 of the showcase is lighted up by the illuminator 36 through the lighting window 38, on the contrary, the rear side space 44 is shut off, by the partition plate 42 and the vertical portion 49 thereof, from the rays of light of the illuminator 36, a temperature difference occurs between the front side space 35 and the rear side space 44, which contributes to natural circulation of the inner gas in the showcase.

That is, the heat energy of the lighting rays is transmitted to the front side space 35 and raise the temperature of the inert gas within the front side space 35.

Since the heated inert gas expands, decreases its density, the gas 54 rises upward in the front side space 35, and thus moves to the rear side space 44 through the upper vent hole 41. Since the inert gas induced to the rear side space 44 is separated from the lighting rays by the plate 42 and the vertical portion 49 thereof, on the contrary, its temperature relatively drops at lower level than that of the

front side space 35 and its density increases. Therefore the inert gas flows down in the space 44 and returns back into the front side space 35 through the lower vent hole 32.

As stated above, The temperature difference between the two space 35 and 44 results in the density difference between two spaces 35 and 44. in addition, As these deference becomes greatly, the circulation of inner gas occurs further actively between two spaces 35 and 44.

The inert gas induced into the rear side space 44, having its temperature higher than the indoor air, is deprived of its heat to the indoor air passing through the flowing path 46 through the radiating plate 45 and becomes cooled gas. Since the inert gas cooled by heat-exchange 53 with the indoor air further increases its density, it flow down easily in the rear side space 44 and then moves back to the front side space 35 through the lower vent hole 32, thus cooling the space 35 effectively. The indoor air heated by heat-exchange 53 with inner gas through the radiating plate 45 during passing through the flowing path 46 flow upward and goes out through the duct 51 to the outside. Here, If the flow rate and the temperature of the indoor air passing through the flowing path 46 is adjusted properly, it is possible to control the cooling speed and amount of showcase.

If the relative humidity within atmosphere surrounding the exhibit changes, the moisture contained within the exhibit is absorbed into or extracted from the exhibit. This coming in and out of moisture is a cause of the deformation of the exhibit. Moreover, this change of humidity is so closely bound up with chemical changes of the exhibit and the increase of microbe, so it is important to adjust the

relative humidity to be suited to the exhibit.

The closed space always contains the a certain absolute amount of the moisture therein. After a certain lapse of time, the water content of the exhibit and the relative humidity of atmosphere surrounding the exhibit are in the equilibrium state. In the preservation of the exhibit, it is important to keep this equilibrium so that the moisture can't move between the exhibit and atmosphere. In order to meet this purpose, the relative humidity of atmosphere surrounding the exhibit should be kept at a constant level since the water content of the exhibit is hardly control.

However, since the relative humidity of atmosphere in the closed space depends on the change of temperature, for example, when 9 grams of moisture is contained in lm3 of the atmosphere, the relative humidity is 50% at 200C )4, but less than 30% at 300C. in order to keep the relative humidity of atmosphere, there is a need of providing the closed space with the material responding mere rapidly than the exhibit and controlling the humidity before the the moving of moisture between the exhibit and atmosphere surrounding it.

Therefore, in the present invention, such material as silica gel, zeolite and the like is employed as a means for adjusting humidity 43. As described above, this material has a great ratio of water content to weight and has been developed to have its proper ability of adjusting humidity.

In the proper range of temperature, this material discharges its moisture therein when meeting with the lower-humidity air and absorbs air's moisture when meeting with higher-humidity air. That is, this material can buffer effectively the change of the humidity of atmosphere,

resulted from the change of-the temperature thereof.

In this embodiment, the inert gas in the front side space 35 has its relative humidity decreased due to the heating by the illuminator 36, the inert gas induced into the space 44, on the contrary, loses its heat and has its relative humidity increased. These increase and decrease of the humidity can be controlled effectively by the means for adjusting humidity 43, which is arranged in the rear side space 44 and adhered to the partition palate 42.

Therefore, while the inert gas flows down in the space 44 keeping on contacting the means for adjusting humidity 43, due to the coming in and out of the moisture 55 between the inert gas and the means for adjusting humidity 43, the relative humidity of the inert gas in whole space of the showcase can be kept at a constant level. As a result, the exhibit can be preserved in it optimum state.

Generally, in showcase which is not closed completely, there is recommended 20kg of silica gel (type 2) per lm3, however, in the complete-closed showcase, there is recommended lkg per lm3. Therefore, if the amount of'the material for adjusting humidity, used in preserving the exhibit, is taken into account, this shows that the closed-type showcase of the present invention is less expensive than the case of the semi-closed type and free from the influence of the humidity change of outer air. If the proper amount of the material (or, the means 43) is provided to the closed-type showcase, it is possible to keep the relative humidity, changing according to the temperature change within the showcase, at a constant level and to protect the exhibit effectively by preventing the moving of moisture between the exhibit and atmosphere surrounding it.

Hereinafter, other embodiment of the present invention will be described referring to Fig. 3.

Fig. 3 shows the second embodiment of the present invention in which the picture frame type exhibit 1 can be on display. Fig. 4 perspectively shows the structural elements of the second embodiment in the Fig. 3 in more detail.

Referring to Fig.3 and Fig. 4, the apparatus in this embodiment, similarly to the previous embodiment, comprises a showcase, as an airtight-box type, in which the exhibit 1 such as painting, picture and the like is received and on play.

This showcase includes: a box-body 4 having its front and rear surfaces opened, which its four edge portion of the front opening, as shown in Fig. 3, is projected inward by a certain length; a front window 3, as a transparent plate-shaped member, which is arranged with its four edge portion seated on the inner surface of the projected portion and shuts down the front opening of the box-body 4; a rear plate 10, acting as a radiating plate for discharging the inner heat of the showcase, which closes the rear opening of the box-body 4; a frame 5 which is located between the front window 3 and the rear plate 10 in the inner space of the box-body 4 and forms the closed space of the showcase along with the front widow 3 and the rear plate 10; a partition plate 7 for dividing the closed space into a front side space 2 and a rear side space 9, which is respectively formed with an upper vent hole 6 and a lower vent hole 13 at its upper and lower portion; a means for adjusting humidity 8, which is located on the rear surface of the partition plate

7 and controlling the relative humidity of inert gas passing through the rear side space 9; a plurality of valves installed respectively at upper and low portion of the rear plate 10 for injecting the closed space of the showcase with inert gas and extracting the air out of the showcase; and the sealing members 12 inserted between the front widow 3 and the frame 5 and between the rear plate 10 and the frame 5 for keeping airtightness of the close space.

The rear plate 10 is fastening down on the rear surface of the box-body 4 by fastener, such as bolt and screw, and shuts down the rear opening of the showcase. At this time, the force fastening the rear plate 10 is transmitted to the front window 3 through the frame 5, thereby sticks the edge portion of the front window 3 fast to the inner surface of the projected portion of the box-body 4, thus keeping the airtightness of the inner closed space formed by the front window 3, the frame 5 and the rear plate 10.

At the upper and lower portion of the rear surface of the box-body 4, a plurality of spacer 14 are respectively disposed so as that the showcase can be located with it spaced out a certain distance from the wall of building, thus forming the flowing path between the wall and the radiating plate (that is, rear plate) 10, where the indoor air 15 absorbs the inner heat of the showcase through the radiating plate 10.

In the front side space 2, the exhibit is hung on the front surface of the partition plate 7 and is on display.

The illumination of the front side space 2 of the showcase is performed by incident rays through the front window 3 from the outside. The front window 3, similarly to the previous embodiment, is made of a material which can

selectively transmits visible rays, at same time,- shuts. off the harmful rays to the exhibit. Therefore, Only visible rays, except for ultraviolet and infrared rays contributes to the illumination of the exhibit and transmits the heat energy thereof to the inert gas within the front side space 2 of the showcase.

The heated inert gas 17 of the front side space 2 is expanded and has its density decreased, thus moving upward in the space 2 and induced into the space 9 through the upper vent hole 6. On the contrary, the inert gas 17 of the rear side space 9, which the absorption of lighting rays is slut off by the partition plate 7, has its temperature drop at a relatively lower level and has its density increase at a relatively higher level than that of the inert gas in the font side space 2, thus moving downward in the space 9 and induced into the space 2 through the lower vent hole 13.

This density difference between the front side space 2 and the rear side space 9 causes the inert gas to circulate naturally between two space 2 and 9. Moreover, since the temperature of the inert gas, which is induced into the rear side space 9 through the upper vent hole 6, is further dropped due to heat-exchange with indoor air through the radiating plate (that is, the rear plate) 10, the density difference stated above is further increased, thereby the circulation of the inert gas is activated greatly.

As described in the fist embodiment, since cooling efficiency depends on the flow rate and the temperature of indoor air flowing through the flowing path formed between the wall and the rear surface of the showcase, if regulating the distance between the wall and the showcase and the temperature of the indoor air, it is possible to control the

inner temperature and humidity of the showcase effectively and uniformly.

Since other operations and effects which are not stated in the description for this embodiment is similar to those of the previous embodiment, it will be omitted hereinafter.

Hereinafter, other embodiment of the present invention will be described referring to Fig. 5.

Fig. 5 shows the third embodiment of the present invention having an electro cooling system for regulating the inner temperature of the showcase further accurately.

As shown in Fig. 5, this embodiment has the similar structural elements to that of the previous embodiment except that the electro cooling system is arranged on the radiating plate. Therefore, the differences, which are distinguished from the previous embodiment, will be mainly described hereinafter.

In this embodiment, the electro cooling system is additionally employed for controlling the inner temperature of the showcase accurately, which includes a electro cooling chip 19 arranged on the rear plate 10 for cooling the heated inert gas of the rear side space 9 through the rear plate 10; a sensor 23 disposed in the rear side space 9 for detecting the temperature of the inert gas passing through the space 9; a controller 21 for receiving the signal detected by the sense 23 and sending control signal to the cooling chip 19; and an insulating material 20 for preventing the heat-exchange between the rear plate 9 and indoor air.

The cooling chip 19 is the semi-conductor well known, which uses the peltier effect that semi-conduct element gets to cool when direct current flows in one direction, on the

contrary, generates heat when direct current flows in opposite direction.

The insulating material 20 is adhered on the whole rear plate 10 except the portion where the chip 19 is located.

Therefore, the cooling of the inert gas passing through the rear side space 9 doesn't depends on the outer heat source (that is, the temperature of indoor air), but depends on the cooling ability of the cooling chip 19 only, and thus it is possible to control the inner temperature of the showcase more precisely and efficiently. In order to increase cooling efficiency, a fan or radiating fin may be arranged on the cooling chip 19.

If the inert gas 17 within the front side space 2 is heated by rays of light incident through the front window 3 and moves upward therein and then the heated inert gas is induced into the rear side space 9 through the upper vent hole 6, the inert gas is deprived of its heat by contacting the inner surface of the rear plate 10 cooled by the cooling chip 19. the cooled inert gas has its density increased at higher level, thus going downward in the rear side space 9 and then moving into the front side space 2.

In this embodiment, the temperature difference between the two spaces 2 and 9 can be directly adjusted by the cooling chip 19 more exactly effectively, and thus the circulation of inert gas between two space 2 and 9 can be activated. As a result, due to the promoting of the move of the moisture 55 between the means for adjusting humidity 8 and the inert gas, the relative humidity of the showcase can be controlled constantly and uniformly, thereby the exhibit on display can be preserved in its optimum state permanently and safely.

Since other operations and effects which are not stated in the description for this embodiment is similar to those of the previous embodiment, it will be omitted hereinafter.

According to the present invention constructed as described above, there is provided with advantages as follows: By excluding harmful rays of light to the exhibit, the discolor and damage thereof are prevented.

By controlling temperature and relative humidity automatically, the damage and deformation of the exhibit due to the constriction and expansion is prevented.

Biological damage by moth, mold, microbe etc. is prevented.

Complete Airtightness of the showcase prevents inflow of pollutant of outer space.

Inert gas injected within the showcase prevents the chemical change of the exhibit.

It can be operated less expensive without a need of equipments for filtering air and adjusting humidity.

The exhibit is free from the vibration and impact since there is not vibration source.

Natural circulation using the density difference of the inert gas with showcase cuts off the operation and maintenance expense.

Circulation of the inert gas prevents a logical heating by the illuminator.

The exhibit on display can be kept and preserved as it is, permanently and safely.

Therefore, it should be understood that the present invention is not limited to the particular embodiment disclosed herein as the best mode contemplated for carrying out the present invention and is not limited to the specific embodiments described in this specification except as defined in the appended claims.