JP7141712B2 - Fireproof double glazing, fireproof glass units and windows of heating cookers - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fire-resistant double-layer glass and a fire-resistant glass unit in which glass sheets are less likely to be thermally cracked in the event of a fire. The present invention also relates to a window of a heating cooker in which the glass plate is less likely to be thermally cracked during cooking.

From the viewpoint of urban fire prevention, quasi-flame-blocking performance is required for openings in the outer walls of buildings where fire may spread in fire-prevention areas or quasi-fire-prevention areas. Therefore, there is a demand for a glass unit that has a fireproof performance that prevents fires that occur around buildings from spreading and prevents flames from entering the interior of the building.

Heretofore, as glass plates used in glass units having such fireproof performance, fire-resistant glass such as wired glass plates, low-expansion glass plates, crystallized glass plates, and heat-resistant tempered glass plates having a surface compressive stress of 190 MPa or more have been used. board was used. In addition, when the glass unit uses double glazing, at least one of the glass plates used therein is the above-described fire glass plate.

Wired glass sheets, however, had appearance problems due to the wire. In addition, low-expansion glass plates and crystallized glass plates are expensive. Furthermore, a heat-resistant tempered glass plate having a surface compressive stress of 190 MPa or more has poor surface flatness and has problems in appearance.

In recent years, the heat insulation performance of buildings has been emphasized from the viewpoint of energy conservation. Widely used for openings in They are often used as double glazing units containing LOW-E glass panes.

Non-Patent Document 1 reports an experimental study on the fire protection performance of tempered LOW-E glass sheets. According to this, when the flame is heated from the LOW-E film side, compared to the case of heating the glass without the LOW-E film or the case of heating from the opposite side of the LOW-E film, the glass It is shown that the temperature difference between the central part and the peripheral part of the plate can be reduced and thermal cracking can be suppressed. However, the effect of suppressing thermal cracking was still insufficient.

Patent Literature 1 describes a single glass for a fire door in which a heat reflective film with low emissivity is provided on at least one side of a glass plate made of heat-strengthened glass or glass subjected to a heat-strengthening treatment exceeding that of heat-strengthened glass. . In addition, the single glass plate and a second glass plate made of heat-strengthened glass or heat-strengthened glass exceeding that of heat-strengthened glass are interposed between the two glass plates with at least one layer of the heat reflecting film. A double glazing for a fire door is described which is arranged facing each other with a gap between them. However, its fireproof performance was insufficient.

Patent Document 2 discloses a double glazing structure in which a plurality of glass plates are spaced apart via spacers and the peripheral edges are sealed with a sealing material. A non-silver-based low-emissivity film is provided on the outer surface of one of the two glass plates arranged in the outermost layer, comprising a fire-resistant glass plate and at least one glass plate that is not a fire-resistant glass plate. A fire-retardant double glazing is described which is characterized by: It is said that the temperature rise rate of the glass can be reduced by placing a scratch-resistant low-emissivity film on the outside. Moreover, it is said that cost increase can be suppressed by using one sheet of inexpensive glass. However, one piece of expensive fireproof glass had to be used, resulting in a cost problem.

WO2013/065641A1 JP 2014-97901 A

"Experimental Study on Fire Performance of Low-E Glass Using Refractory Furnace" Kazuyuki Suzuki et al., Journal of Environmental Engineering, Architectural Institute of Japan, Vol.81, No.727, p739-747, September 2016

The present invention has been made to solve the above problems, and an object of the present invention is to provide a fire-resistant double-layer glass and a fire-resistant glass unit that do not use expensive glass plates and have a good appearance and excellent fireproof performance. It is. Another object of the present invention is to provide a window of a heating cooker that reduces the number of expensive glass plates, has a good appearance, and has excellent heat shielding performance.

The above-mentioned problem is a fireproof double glazing in which two glass plates are laminated via a spacer disposed on the outer periphery thereof; the first glass plate and the second glass plate are arranged in order from the side opposite to the flame. A LOW-E film is formed on the flame-side surface of the first glass plate, the LOW-E film in the vicinity of the spacer is removed, and the entire surface of the second glass plate opposite to the flame is formed. The problem is solved by providing a fireproof double glazing on which a LOW-E film is formed. At this time, it is preferable that the surface compressive stress of the first glass plate is 60 MPa or more and less than 190 MPa, and the surface compressive stress of the second glass plate is less than 60 MPa. Moreover, it is also preferable that the removal width (W) of the LOW-E film on the first glass plate is 2 to 20 mm from the edge of the spacer.

Further, the above-mentioned problem is a fireproof double-layered glass in which three glass plates are laminated via spacers arranged on the outer periphery thereof; the first glass plate, the second glass plate and the A third glass plate is arranged, a LOW-E film is formed on the flame-side surface of the first glass plate, the LOW-E film near the spacer is removed, and the second glass plate and the third glass plate are Another solution is to provide a fire rated double glazing in which a LOW-E film is formed on the entire flame-opposite surface of the glass sheet. At this time, it is preferable that the surface compressive stress of the first glass plate is 60 MPa or more and less than 190 MPa, and the surface compressive stress of the second glass plate and the third glass plate is less than 60 MPa. Moreover, it is also preferable that the removal width (W) of the LOW-E film on the first glass plate is 2 to 20 mm from the edge of the spacer.

A preferred embodiment of the present invention is a fire glass unit comprising any one of the double glazings described above, a frame holding the double glazing, and a sealing material sealing a gap between the double glazing and the frame. be. At this time, the ratio (W/D) of the removal width (W) to the entrainment depth (D) of the first glass plate is preferably 0.5-2.

The above problem is a fire glass unit comprising a single-layer glass plate, a frame for holding the glass plate, and a sealing material for sealing a gap between the glass plate and the frame; the flame side of the glass plate. The problem can also be solved by providing a fire glass unit in which a LOW-E film is formed on the surface of the glass and the LOW-E film in the vicinity of the sealant is removed. At this time, it is preferable that the surface compressive stress of the glass plate is 60 MPa or more and less than 190 MPa. It is also preferable that the removal width (W) of the LOW-E film on the glass plate is 2 to 20 mm from the edge of the sealing material. It is also preferable that the ratio (W/D) of the removed width (W) to the entrapment depth (D) of the glass plate is 0.5-2.

Further, the above-mentioned problem is a window of a heating cooker in which two glass plates are fixed in parallel with a predetermined interval; , a first glass plate is held by a frame, a LOW-E film is formed on the inner surface of the first glass plate, the LOW-E film in the vicinity of the frame is removed, and a second The problem can also be solved by providing a window of a heat cooker, wherein the glass plate is a low-expansion glass plate, a crystallized glass plate, or a heat-resistant tempered glass plate having a surface compressive stress of 190 MPa or more. At this time, the surface compressive stress of the first glass plate is preferably 20 MPa or more and less than 190 MPa. Moreover, it is also preferable that the removal width (W) of the LOW-E film in the first glass plate is 2 to 20 mm from the edge of the frame.

INDUSTRIAL APPLICABILITY The fire-resistant double-glazed glass and fire-resistant glass unit of the present invention have a good appearance and excellent fireproof performance, although they do not use expensive glass plates. Therefore, it is possible to prevent a fire that occurs around the building from spreading and prevent flames from entering the interior of the building. In addition, the window of the heat cooking machine of the present invention reduces the number of expensive glass plates, has a good appearance, and is excellent in heat shielding performance.

1 is a schematic cross-sectional view of an example of a fire glazing unit of the present invention comprising a single sheet of glass; FIG. It is the graph which showed the temperature change of the center part of a glass plate. 4 is a graph showing temperature changes of the glass plate at the end position of the sealing material. It is the graph which showed the temperature change of the edge of the glass plate swallowed by the frame. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic cross section of an example of the fireproof double glazing of this invention in which two glass plates are laminated|stacked. 1 is a schematic cross-sectional view of an example of a fire glass unit of the present invention including double glazing formed by laminating two glass plates. FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic cross section of an example of the fireproof double glazing of this invention in which three glass plates are laminated|stacked. FIG. 2 is a schematic cross-sectional view of an example of the window of the heating cooking machine of the present invention, which is formed by laminating two glass plates.

A first aspect of the present invention is a fire glass unit comprising a single-layer glass plate, a frame holding the glass plate, and a sealing material sealing a gap between the glass plate and the frame; The fire glass unit has a LOW-E film formed on the flame-side surface of the glass plate, and the LOW-E film in the vicinity of the sealant is removed. Description will be made below with reference to FIG.

The fire glass unit 1 shown in FIG. 1 includes a single-layer glass plate 10, a frame 31 that holds the glass plate 10, and a sealing material 32 that seals a gap between the glass plate 10 and the frame 31. . Although FIG. 1 shows only the lower side of the fireproof glass unit 1, all four sides have the same configuration. It is the purpose of the fire glass unit 1 of the present invention to prevent the fire from spreading from the side where the flame 2 exists to the opposite side. Normally, the place where the flame 2 exists is outdoors, and the spread of the fire from there to the inside of the building is prevented.

Although the material of the glass plate 10 is not particularly limited, soda-lime glass is usually used. The surface compressive stress of the glass plate 10 is preferably 60 MPa or more and less than 190 MPa. When the surface compressive stress is 60 MPa or more, the occurrence of thermal cracks when exposed to flame can be suppressed. Here, thermal cracking refers to cracking caused by a temperature difference in a single glass plate. When a fire occurs, the central portion of the glass plate quickly becomes hot, while the temperature of the peripheral portion swallowed by the frame 31 remains low. At this time, tensile stress is generated at the edge of the glass plate due to the stress generated by the expansion of the central portion of the glass plate compared to the peripheral portion, and thermal cracking occurs. The surface compressive stress is more preferably 80 MPa or higher, and even more preferably 90 MPa or higher. On the other hand, if the surface compressive stress is too high, the glass sheet will bend and the appearance will deteriorate. When the surface compressive stress is less than 190 MPa, the surface of the glass plate becomes smooth. The surface compressive stress is more preferably less than 150 MPa, even more preferably less than 130 MPa. Although the thickness of the glass plate is not particularly limited, it is usually 2 to 10 mm.

A LOW-E film 20 is formed on the surface of the glass plate 10 on the flame 2 side. Since the LOW-E film 20 is formed on the surface on the flame 2 side, infrared rays generated from the flame 2 are reflected by the LOW-E film 20 . As a result, the amount of infrared rays entering the glass plate 10 can be suppressed, and the rate of temperature rise of the glass plate 10 can be reduced.

The LOW-E film 20 is a coating that transmits visible light and reflects infrared light. The composition of the coating is not particularly limited. One of the typical materials is tin oxide (SnO ₂ ) as a main component, which may be doped with other atoms such as fluorine. Such a tin oxide-based LOW-E film does not have a very low emissivity, but the strength of the film is high and it does not deteriorate due to oxidation. Even if it is glass, it is preferably used when it is provided in the outermost layer. Another typical example includes a low-emissivity metal layer such as silver. For example, a film in which a silver layer and a zinc layer are alternately laminated can be used. Such a low-emissivity metal-based, especially silver-based LOW-E film has a low emissivity, and is therefore excellent in both fire prevention and heat insulation effects. However, since the film is easily oxidized and easily damaged, it is difficult to use it for the outermost layer, and it is often used for the inner surface of double glazing. The emissivity of the LOW-E film 20 is preferably 0.3 or less, more preferably 0.2 or less, and even more preferably 0.1 or less.

The greatest feature of the fire protection glass unit 1 of the present invention is that the LOW-E film 20 near the sealing material 32 is removed. Most of the infrared rays generated from the flame 2 can enter the glass plate 10 at the portion where the LOW-E film 20 is removed. Thereby, the temperature of the removed portion of the glass plate 10 can be increased. By raising the temperature of this portion, heat is transferred to the portion swallowed by the frame 31, and the temperature of the edge of the glass plate 10 can be raised by heat transfer. That is, the LOW-E film 20 suppresses the temperature rise at the central portion of the glass plate 10, and the edge of the glass plate 10 swallowed by the frame 31 is removed by removing the LOW-E film 20 in the vicinity of the sealing material 32. As a result, the temperature difference between the two can be reduced, and thermal cracking can be effectively suppressed. Although the material of the sealing material 32 is not particularly limited, a silicone sealant or the like is preferably used.

A method for removing the LOW-E film 20 near the sealing material 32 is not particularly limited. It can be removed mechanically using a grinding device, can be removed thermally by irradiating it with a laser beam, or can be removed using a chemical agent. In order to improve the adhesiveness between the sealing material and the glass plate, it has been conventional practice to remove the LOW-E film at the position in contact with the sealing material. However, in spite of the demerits in heat insulation performance and appearance, the LOW-E film at the position not in contact with the sealing material has not been dared to be removed.

In order to quantitatively grasp this effect, a temperature simulation was performed with the configuration of the fire protection glass unit 1 shown in FIG. An analytical model was used in which a glass plate with a thickness of 3 mm was embedded in the sealing material 32 with a swallowing depth (D) of 10 mm. Modeling was performed in Autodesk Inventor using Nastran In CAD as the solver. Boundary conditions were set by setting radiation and convection conditions based on ISO 15099. The combustion curve of ISO_834 was used for the convection condition on the flame side. Radiation conditions on the flame side are described in the author, Daisuke Kamikawa, 2nd (2005) Tsuboi Memorial Research Grant, "Elucidation of Heat Balance Characteristics of Refractory Heating Furnace and Proposal Report of Reproduction Method of Fire Decay Period in Wooden Fire-Resistant Structural Test" (published March 2006) (Fig.2.11, Fig.3.4, Fig.3.9, Fig.3.14, Fig.3.19), the temperature near the glass and the temperature difference near the burner at a distance of 900 mm was estimated and adjusted by adding 100°C to ISO_834.

The physical property parameters used for the analysis are as follows.
Low emissivity film emissivity (ε): 0.05
Emissivity of glass without low emissivity coating (ε): 0.4
Thermal conductivity of sealing material: 0.4 W/m K
Heat transfer coefficient of air: 0.07 W/m K
Thermal conductivity of glass: 1.0 W/m K

The results of the simulation are shown in Figures 2-4. FIG. 2 shows the temperature change at the central portion of the glass plate 10. The black circles are the temperature of the LOW-E film 20 surface, and the white circles are the temperature of the rear glass plate 10 surface. The temperature at the central portion of the glass plate 10 does not change significantly even if the width (W) of removal from the end of the sealing material 32 is changed. FIG. 3 shows the temperature change of the glass plate 10 at the end position of the sealing material 32. As shown in FIG. Also, FIG. 4 shows the temperature change at the edge of the glass plate 10 swallowed by the frame 31 . FIGS. 3 and 4 show temperature changes of the glass when the removal width W of the LOW-E film 20 is changed.

As shown in FIG. 2, the temperature at the central portion of the glass plate 10 rises linearly after the start of flame radiation, and then the rate of rise decreases with the lapse of time. At this time, there is almost no temperature difference between the front and back surfaces of the glass plate 10 . On the other hand, as shown in FIG. 3, at the end position of the sealing material 32, the initial temperature rise rate is slightly lower, but after a short delay, the temperature rise rate increases. Further, as shown in FIG. 4, at the edge of the glass plate 10, the initial temperature rise rate becomes even lower, and after a short delay, the temperature rise rate increases.

The temperature at the center of the glass plate 10 rises first, followed by the temperature at the edge of the glass plate 10 . Therefore, in order to reduce the temperature difference between the central portion and the peripheral portion, it is important to quickly raise the temperature of the peripheral portion of the glass plate 10 . Here, as can be seen from FIGS. 3 and 4, by removing the LOW-E film 20 in the vicinity of the sealing material 32, it was found that the rate of temperature rise can be effectively improved. Moreover, surprisingly, it has been found that even a slight removal width is effective. As shown in Figures 3 and 4, it is surprising that removing only a width of 5 mm does not make a big difference compared to removing a width of 40 mm. Considering the heat insulating effect, the smaller the area to be removed, the better. Therefore, it is extremely useful to recognize a sufficient heating effect on the edge of the glass plate 10 even when the area is removed in a small area.

It is preferable that the removal width (W) of the LOW-E film 20 is 2 to 20 mm from the edge of the sealing material. By setting the removal width (W) to 2 mm or more, the temperature of the edge of the glass plate 10 can be raised quickly. The removal width (W) is more preferably 3 mm or more, and even more preferably 4 mm or more. On the other hand, if the removal width (W) exceeds 20 mm, the heat insulating property of the fire protection glass unit 1 is lowered, and the boundary between the presence and absence of the LOW-E film 20 becomes more noticeable. The removal width (W) is more preferably 15 mm or less, and even more preferably 10 mm or less.

The swallowing depth (D) of the glass plate 10 is adjusted according to the design of the fire glass unit 1, but is usually 3-25 mm. If the swallowing depth (D) is too small, the glass plate 10 may come off the frame 31 due to external force or heat. The swallowing depth (D) is more preferably 5 mm or more, and even more preferably 7 mm or more. On the other hand, if the entrapment depth (D) is too large, it becomes difficult to heat the edge of the glass plate 10, and thermal cracking may easily occur. The swallowing depth (D) is more preferably 20 mm or less, and even more preferably 15 mm or less.

It is also preferable that the ratio (W/D) of the removed width (W) to the swallowing depth (D) of the glass plate 10 is 0.5-2. The removal width (W) is proportional to the area that absorbs infrared rays, and the entrapment depth (D) is proportional to the heat capacity to be heated by heat transfer. Therefore, it is preferable that these values are properly balanced. The ratio (W/D) is more preferably 0.6 or more, even more preferably 0.7 or more. On the other hand, the ratio (W/D) is more preferably 1.8 or less, even more preferably 1.6 or less.

A second aspect of the present invention is a fire-resistant double glazing in which two glass plates are laminated via a spacer disposed on the outer periphery thereof; When two glass plates are used, a LOW-E film is formed on the flame-side surface of the first glass plate, the LOW-E film near the spacer is removed, and the second glass plate is opposite to the flame. It is a fireproof double glazing with a LOW-E film formed on the entire side surface. Description will be made below with reference to FIG.

The fireproof multi-layered glass 3 shown in FIG. 5 is formed by laminating a first glass plate 11 and a second glass plate 12 via spacers 33 arranged on the outer peripheral portions thereof. A sealing material 34 is arranged on the outer peripheral side of the spacer 33 . Although FIG. 5 shows only the lower side of the fireproof double glazing 3, all four sides have the same configuration. Here, the first glass plate 11 and the second glass plate 12 are arranged in order from the farthest from the flame 2 . It is the purpose of the fireproof double glazing 3 of the present invention to prevent the fire from spreading from the side where the flame 2 exists to the opposite side. Although the material of the spacer 33 is not particularly limited, a metal such as stainless steel is preferably used. Also, the material of the sealing material 34 is not particularly limited, but a silicone sealant or the like is preferably used.

The materials of the first glass plate 11 and the second glass plate 12 are the same as those of the glass plate 10 of the first aspect. Also, the surface compressive stress of the first glass plate 11 is the same as that of the glass plate 10 . The surface compressive stress of the second glass plate 12 is preferably less than 60 MPa. Since the second glass plate 12 is the first to crack when exposed to flame, the surface compressive stress should not be too large so as not to break the first glass plate 11 by scattering fragments when it breaks. More preferably, the surface compressive stress of the second glass plate is less than 50 MPa. On the other hand, in order to increase the strength of the second glass plate, the surface compressive stress of the second glass plate is more preferably 20 MPa or more.

A LOW-E film 21 is formed on the surface of the first glass plate 11 on the flame 2 side. The role and configuration of the LOW-E film 21 are the same as those of the LOW-E film 20 formed on the glass plate 10 of the first aspect. A LOW-E film 22 is formed on the entire surface of the second glass plate 12 opposite to the flame 2 . By forming the LOW-E film 22 on the entire surface, a double glazing with good heat insulation can be obtained. The type of the LOW-E film 22 is also the same as the LOW-E film 20 formed on the glass plate 10 of the first embodiment. However, unlike the first mode, the LOW-E films 21 and 22 are not arranged in the outermost layer, so if fireproof performance and heat insulation performance are considered, low-emissivity metal-based, especially silver-based LOW-E films is preferably used.

The greatest feature of the second aspect of the fireproof double glazing 3 is that the LOW-E film 21 near the spacer 33 is removed. This point is the same as the LOW-E film 20 in the vicinity of the sealing material 32 is removed in the first mode. The effect is also the same as that simulated by the model of the first mode. A suitable removal width (W) is also the same as in the first mode. Also, the preferred entrapment depth (D) of the glass plate 11 and the preferred ratio (W/D) of the removed width (W) to the entrainment depth (D) are the same as in the first embodiment.

A preferred embodiment is, as shown in FIG. 32 is a fire glass unit 1. A setting block may be arranged at the position of the sealing material 32 on the lower side of the four sides of the fireproof glass unit 1 to support the fireproof double glazing 3 . In this case, the periphery of the setting block is sealed with the sealing material 32 . The material of the setting block is not particularly limited, but an elastomer such as EPDM is preferably used.

In the fire protection glass unit 1 of the second aspect, two layers of LOW-E films are provided, and the LOW-E film 22 is formed on the entire surface of the glass plate 12 . Moreover, since neither of the LOW-E films 21 and 22 is arranged as the outermost layer, a low-emissivity metal-based film having a low emissivity, particularly a silver-based LOW-E film can be used. Therefore, both fireproof performance and heat insulating performance are superior to those of the first mode.

A third aspect of the present invention is a fire-resistant double-layered glass in which three glass plates are laminated via spacers disposed on their outer peripheral portions; A second glass plate and a third glass plate are arranged, a LOW-E film is formed on the flame-side surface of the first glass plate, the LOW-E film is removed in the vicinity of the spacer, and the second glass plate is This is a fireproof double glazing in which a LOW-E film is formed on the entire surface of the plate and the third glass plate on the side opposite to the flame. Description will be made below with reference to FIG.

The fire resistant double glazing 3 shown in FIG. 7 includes two glass panes 11 and 12 of FIG. It is the same as the fireproof double glazing 3 . A LOW-E film 23 is formed on the entire surface of the third glass plate 13 opposite to the flame 2 . A spacer 33 and a sealing material 34 are arranged between the second glass plate 12 and the third glass plate 13 . Similar to FIG. 6, a fire-resistant glass unit 1 comprising a fire-resistant double-glazed glass 3, a frame 31 holding the double-glazed glass 3, and a sealing material 32 sealing a gap between the double-glazed glass 3 and the frame 31. is the preferred embodiment.

In the fire glass unit 1 of the third aspect, three layers of LOW-E films are provided, two of which LOW-E films 22 and 23 are formed on the entire surfaces of the glass plates 12 and 13 . In addition, since none of the LOW-E films 21, 22, and 23 is disposed on the outermost layer, a low-emissivity metal-based film, particularly a silver-based LOW-E film having a low emissivity can be used. Therefore, both fireproof performance and heat insulating performance are superior to those of the second aspect.

In the fire glass units 1 of the first, second, and third embodiments, the glass plate 10 or the first glass plate 11 is not easily cracked by heat and is flat, so that it has excellent fireproof performance and an excellent appearance. Then, if a configuration including double glazing is used as in the second and third aspects, the fire glass unit 1 having excellent heat insulating properties can be obtained. Therefore, it can be widely used mainly for the purpose of preventing the spread of fire from the outside in windows and doors of houses and buildings.

A fourth aspect of the present invention is a window of a heating cooking machine in which two glass plates are fixed in parallel with a predetermined interval; the first glass plate and the second glass in order from the outside of the cooking machine A plate is arranged, a first glass plate is held by a frame, a LOW-E film is formed on the inner surface of the first glass plate, and the LOW-E film in the vicinity of the frame is removed. and the second glass plate is a low-expansion glass plate, a crystallized glass plate, or a heat-resistant tempered glass plate having a surface compressive stress of 190 MPa or more. Description will be made below with reference to FIG.

A first glass plate 11 and a second glass plate 12 are fixed in parallel with each other at a predetermined interval in the window 4 of the cooking machine shown in FIG. A second glass plate 12 is placed on the side of the heat source 5 inside the cooking machine, and a first glass plate 11 is placed outside the cooking machine. The window 4 of the cooking machine of the present invention suppresses heat rays from being emitted to the outside of the cooking machine.

The material and surface compressive stress of the first glass plate 11 are the same as those of the glass plate 10 of the first aspect. On the other hand, the second glass plate 12 is a low-expansion glass plate, a crystallized glass plate, or a heat-resistant tempered glass plate having a surface compressive stress of 190 MPa or more. The second glass plate 12 is close to the heat source 5, and a tempered glass plate having a surface compressive stress of less than 190 MPa has insufficient heat resistance. Low-expansion glass is glass having a small coefficient of linear expansion, and synthetic quartz glass, borosilicate glass, or the like can be used. The crystallized glass is a glass having both crystallinity and transparency, and heat-resistant crystallized glass "Neoceram" manufactured by Nippon Electric Glass Co., Ltd. can be used as the crystallized glass. Since these glasses have a small coefficient of linear expansion, they are less likely to break even when heated. However, there is a demand for suppressing the number of sheets used due to the high cost. Further, the heat-resistant strengthened glass plate having a surface compressive stress of 190 MPa or more can use soda-lime glass, which is cheaper than low-expansion glass or crystallized glass. However, the generation of a large surface compressive stress tends to cause deterioration in flatness accuracy and optical distortion.

A LOW-E film 21 is formed on the surface of the first glass plate 11 on the heat source 5 side. The role and configuration of the LOW-E film 21 are the same as those of the LOW-E film 20 formed on the glass plate 10 of the first aspect. When the space between the first glass plate 11 and the second glass plate 12 is sealed, it is preferable to use a low-emissivity metal-based, especially silver-based LOW-E film, thereby improving the heat shielding performance. improves. On the other hand, if the space between the first glass plate 11 and the second glass plate 12 is not sealed and is connected to the outside air, it is preferable to use a tin oxide-based LOW-E film.

The greatest feature of the window 4 of the cooker of the present invention is that the LOW-E film 21 near the frame 31 is removed. This point is the same as the LOW-E film 20 in the vicinity of the sealing material 32 is removed in the first mode. The effect is also the same as that simulated by the model of the first aspect. A suitable removal width (W) is also the same as in the first mode. Also, the preferred entrapment depth (D) of the glass plate 11 and the preferred ratio (W/D) of the removed width (W) to the entrainment depth (D) are the same as in the first embodiment.

The window 4 of the cooker of the present invention has a frame 31 that holds the first glass plate 11 fixed to an outer frame 35 . When sealing the space between the first glass plate 11 and the second glass plate 12, the frame 31 is provided over the entire circumference, and a sealing material is inserted between the first glass plate 11 and the frame 31. . On the other hand, when the space between the first glass plate 11 and the second glass plate 12 is not sealed, there is no need to insert a sealing material between the first glass plate 11 and the frame 31, and the frame 31 is They may be arranged intermittently. Even in such a case, the removal width (W) refers to the width from the edge of the frame 31 .

In the window of the cooker 4 of the present invention, the first glass plate 11 is flat and has a good appearance. Therefore, it can be suitably used as a door of various heat cookers such as ovens. When used as a door of a cooking machine, the frame 31 holding the first glass plate 11 is fixed to the door body, and the second glass plate 12 is also fixed to the door body.

1 fireproof glass unit 2 flame 3 fireproof double glazing 4 window of cooking machine 5 heat source 10 glass plate 11 first glass plate 12 second glass plate 13 third glass plate 20, 21, 22, 23 LOW-E film 31 frame Body 32, 34 Sealing material 33 Spacer 35 Outer frame

Claims (14)

A fireproof double glazing in which two glass plates are laminated via a spacer disposed on the outer periphery thereof;
A first glass plate and a second glass plate are arranged in order from the opposite side of the flame,
A LOW-E film is formed on the flame-side surface of the first glass plate, the LOW-E film in the vicinity of the spacer is removed, and a LOW-E film is formed on the entire surface of the second glass plate opposite to the flame. A fireproof double glazing on which an E film is formed. The double glazing according to claim 1, wherein the first glass plate has a surface compressive stress of 60 MPa or more and less than 190 MPa, and the second glass plate has a surface compressive stress of less than 60 MPa. A fireproof double glazing in which three glass plates are laminated via a spacer arranged on the outer periphery thereof;
A first glass plate, a second glass plate and a third glass plate are arranged in order from the side opposite to the flame,
A LOW-E film is formed on the flame-side surface of the first glass plate, the LOW-E film in the vicinity of the spacer is removed, and the flame-side surfaces of the second and third glass plates A fireproof double glazing with a LOW-E film formed over the entirety of the glass. The double glazing according to claim 3, wherein the surface compressive stress of the first glass plate is 60 MPa or more and less than 190 MPa, and the surface compressive stress of the second glass plate and the third glass plate is less than 60 MPa. The double glazing according to any one of claims 1 to 4, wherein the removal width (W) of the LOW-E film on the first glass plate is 2 to 20 mm from the edge of the spacer. A fire glass unit comprising the double glazing according to any one of claims 1 to 5, a frame holding the double glazing, and a sealing material for sealing a gap between the double glazing and the frame. 7. The glass unit according to claim 6, wherein the ratio (W/D) of the removal width (W) to the entrainment depth (D) of the first glass plate is 0.5-2. A fire glass unit comprising a single-layer glass plate, a frame for holding the glass plate, and a sealing material for sealing a gap between the glass plate and the frame;
A fire glass unit, wherein a LOW-E film is formed on the flame-side surface of the glass plate, and the LOW-E film is removed in the vicinity of the sealant. The glass unit according to claim 8, wherein the glass plate has a surface compressive stress of 60 MPa or more and less than 190 MPa. 10. The glass unit according to claim 8, wherein the removal width (W) of the LOW-E film on the glass plate is 2 to 20 mm from the edge of the sealing material. The glass unit according to any one of claims 8 to 10, wherein the ratio (W/D) of the removal width (W) to the entrainment depth (D) of the glass plate is 0.5-2. A window for a cooking machine, in which two glass plates are fixed in parallel with a predetermined interval;
A first glass plate and a second glass plate are arranged in order from the outside of the cooking machine,
The first glass plate is held by the frame,
A LOW-E film is formed on the inner surface of the first glass plate, the LOW-E film in the vicinity of the frame is removed, and the second glass plate is a low-expansion glass plate or crystallized glass. A window of a heat cooker, which is a plate or a heat-resistant tempered glass plate having a surface compressive stress of 190 MPa or more. 13. The window according to claim 12, wherein the surface compressive stress of the first glass plate is 20 MPa or more and less than 190 MPa. 14. The window according to claim 12 or 13, wherein the removal width (W) of the LOW-E film in the first glass plate is 2 to 20 mm from the edge of the frame.

Images