WO2024133113A1

WO2024133113A1 - Corner connector for fire-protection glazing units

Info

Publication number: WO2024133113A1
Application number: PCT/EP2023/086408
Authority: WO
Inventors: Markus Thiede; Hans Guido PLUM; Jerome KORUS; Heiko HOLTSCHNEIDER
Original assignee: Saint-Gobain Glass France
Priority date: 2022-12-22
Filing date: 2023-12-18
Publication date: 2024-06-27

Abstract

Corner connector (I) for connecting two ends of at least one profile strip in fire-protection glazing units, comprising two plug-in legs (31), suitable for plugging into a profile strip (1), and a connection region (34), which connects the two plug-in legs (31), comprising an outer surface (39), two pane contact surfaces (40) and an inner surface (41), wherein - a cutout (33) is made in the corner connector (I) and is suitable, in a fire-protection glazing unit (II), for producing a passage from the surroundings to the inner pane gap (12), and - a backflow preventer (32) is inserted into the cutout (33) or adjacent to the cutout (33) and is suitable for allowing the flow of a free-flowing fire-protection compound through the cutout (33) from the surroundings into the pane gap (12) and for preventing the backflow of a free-flowing fire-protection compound through the cutout (33) from the pane gap (12) in the direction of the surroundings.

Description

Corner connectors for fire protection glazing

The invention relates to a corner connector for fire-resistant glazing, a fire-resistant glazing and a method for its production.

In the event of a fire, fire-resistant glazing is used to protect people and objects on one side of the glazing from a fire on the other side of the glazing. In this case, not only is smoke protection generally desired, but a heat barrier should also be created, at least temporarily. In normal operation, however, the fire-resistant glazing should act like a normal transparent glazing element. One category of fire-resistant glass has at least two, usually transparent, panes between which a fire protection layer is inserted. The fire protection layer, also known as a fire protection interlayer or fire protection gel, has, for example, a foaming, heat-insulating and/or cooling material. The material of the fire protection layer is, for example, an alkali polysilicate with the highest possible water content. Water-containing, organic, gel-like polymer hydrogels are also known as materials for fire protection layers. What the fire protection layers have in common is that they are transparent at room temperature, but become cloudy and/or foam when exposed to heat, which is where the insulating effect unfolds.

From DE 3037015 A1 a spacer frame made of C-shaped profile sections for fire-resistant glass panes is known, wherein a gap between two silicate glass panes is filled with a gel-like material containing salt and water.

Alkali silicates are completely transparent under normal application conditions, but begin to cloud and foam irreversibly at temperatures of around 80 °C. Such fire protection glazing can be produced by applying a thin layer of alkali silicate in liquid form to one side of a first pane and then drying it. This drying step is complex and delays the production process. A second pane is then glued onto the intermediate or protective layer made of alkali silicate. Such a production process is time-consuming and it is difficult to guarantee consistent product quality, particularly with regard to air inclusions. In this respect, WO 94/04355 A1 proposes a process in which the fire protection layer can be produced by casting and without drying. The fire protection layer of WO 94/04355 A1 is a layer made of alkali silicate and Polysilicate formed from at least one hardener, the starting material of which is flowable and suitable for pouring into cavities. A chamber formed by the space between two (or more) panes is sealed all the way around the edge of the panes, a hole is made in the seal and the chamber is filled with the starting material of a fire protection layer in liquid or pasty form through the hole. The hole is then sealed and the fire protection compound hardens to form a fire protection layer.

Filling the chamber of a fire protection glass with the flowable fire protection compound is a process that usually involves a large number of manual steps. For example, the fire protection compound is manually filled into the chamber formed between the panes using a hose, and the bubbles that form during filling are manually released. The open filling opening is then manually closed and sealed. WO 03/031173 A1 discloses a method for filling fire protection glass in which the filling opening is closed with a driver plug after filling and the cavity is simultaneously vented. In order to simplify filling the chamber of a fire protection glass, according to DE 102007020537 A1, a sleeve can be inserted into the circumferential seal, which extends from the interior of the chamber to the outside and contains a sealing element. EP 3165700 A1 describes a filling device for fire protection glass, which comprises a filling connection for filling the fire protection material at a lower filling opening and a venting device for connection to an upper venting opening of the fire protection glass, wherein the venting device comprises a venting channel with a swelling agent that swells upon contact with the fire protection compound to close the venting channel. Filling takes place via a hose, wherein any fire protection compound remaining in the hose can be polymerized with the hose and then removed.

EP 3002122 A1 discloses a device and a method for producing fire-resistant glass, wherein a first pane and a second pane are connected at a distance from one another and filled with a flowable fire-resistant compound, which is cured in a subsequent step to form a fire-resistant gel.

WO 02/100636 A1 describes a device for filling a space between panes with intumescent organic fire protection compounds. The fire protection compound is filled in the form of an aqueous solution with a high water content. The aqueous solution is mixed in a container and before being filled into a Glazing blank is degassed and its volume reduced by evaporation of a water portion under vacuum.

DE102018109278B4 discloses a spacer frame for fire protection glazing with corner connectors, wherein the corner connectors comprise a filling opening for filling in a flowable fire protection compound. The filling opening consists of a hole in the corner area of the corner connector, through which a lance can be inserted into the fire protection glazing blank for filling. When the lance is removed, part of the fire protection compound can flow back if the filling opening is not closed quickly enough using an externally attached mechanism. This is not part of the corner connector, but must be provided separately during the filling process.

EP 0569298 A1 discloses a device for equalizing pressure between the internal atmosphere and the external environment of an insulating glazing, which comprises a closure made of fusible metal in the corner angle of the insulating glazing, wherein the closure melts in the event of a fire and thus enables air exchange and the associated pressure equalization. There is no fire protection layer between the panes of the insulating glazing. In the presence of the closure, it closes the opening in the corner angle so that no exchange of substances or gases is possible through the corner angle.

WO 2017/064166 A1 discloses a connector for connecting two hollow profile strips, comprising a membrane, wherein the membrane is gas-permeable and water vapor-tight and preferably comprises expanded microporous polytetrafluoroethylene. This membrane is intended for gas exchange through the corner connector, but not for liquid exchange. It is not possible to fill a large amount of flowable mass into the space between the panes via the membrane within a short time.

There is a need for corner connectors for fire-resistant glazing that allow the fire-resistant glazing to be filled quickly and easily, a fire-resistant glazing that can be filled in a simple manner and a method for filling a fire-resistant glazing. The present invention is based on the object of providing such a corner connector, a fire-resistant glazing and an improved method for filling the fire-resistant glazing.

The object of the present invention is achieved by a corner connector according to claim 1. Preferred embodiments emerge from the subclaims A fire-resistant glazing according to the invention and a method for its production emerge from further independent claims.

The corner connector according to the invention serves to connect two ends of at least one profile strip in fire-resistant glazing and comprises two plug-in legs that are suitable for being inserted into or plugged onto a profile strip. The two plug-in legs are linked to one another via a connecting area that connects the two plug-in legs and comprise an outer surface, two side surfaces and an inner surface. A recess is provided in the corner connector that is suitable for creating a passage from the environment to the inner space between the panes when installed in fire-resistant glazing. The recess therefore connects the outer surface of the corner connector with its inner surface and is thus designed continuously through the corner connector. A backflow preventer is inserted into the recess of the corner connector or adjacent to the recess. In the recess means that the backflow preventer is fixed within the recess and is therefore inserted into the recess between the inner surface and the outer surface of the corner connector. A backflow preventer inserted into the recess can, depending on its design and geometry, also extend out of the recess and protrude beyond the inner surface of the corner connector into the space between the panes of the fire-resistant glazing. A backflow preventer that is installed adjacent to the recess is attached to the inner surface or outer surface of the corner connector adjacent to the recess and covers an opening in the recess on the surface to which it is attached. The backflow preventer installed in the recess or adjacent to the recess is suitable for preventing the flow of a flowable fire protection compound through the recess from the space between the panes towards the environment. When the corner connector is installed in a spacer frame for fire-resistant glazing, the fire protection compound can be filled through the recess into the space between the panes, for example using a filling lance. After removing the filling lance, the backflow preventer within the recess prevents the fire protection compound from flowing back through the recess out of the space between the panes.

The corner connector according to the invention enables a simple, bubble-free filling of fire protection glazing with fire protection compound, whereby the backflow of the fire protection compound is prevented after the filling process. This prevents the formation of air bubbles in the space between the panes. The backflow preventer is attached to the corner connector It is easily integrated into the spacer frame, with no additional steps required to integrate the backflow preventer.

Filling a fire protection glazing with a corner connector according to the invention is preferably carried out using a filling lance that is inserted through the recess into the space between the panes. However, the filling process can also be carried out in another way, for example by placing a line on the surface of the recess facing the environment. According to the invention, the backflow preventer enables a flowable fire protection compound to flow through the recess from the environment into the space between the panes. This means that the backflow preventer according to the invention is suitable for enabling a flow of compound from the environment into the interior of the glazing, but prevents this in the opposite direction. This criterion also applies if a filling lance is to be inserted into the recess of the corner connector. The backflow preventer is integrated into the corner connector itself and does not have to be removed after the filling process. In a non-inventive design of the corner connector without a backflow preventer, the fire protection compound would flow out of the space between the panes through the recess after the filling process has been completed, so that the recess must be closed promptly, for example with a plug. The backflow preventer of the corner connector according to the invention prevents such unhindered backflow of the fire protection compound out of the space between the panes. This is advantageous in order to avoid the formation of air bubbles in the space between the panes and to facilitate the filling process.

The recess of the corner connector can be chosen as desired in terms of its cross-section geometry and depending on the geometry of the non-return valve to be used. The recess has, for example, a round, oval or square cross-section, preferably a round or oval cross-section.

The corner connector is suitable for connecting two ends of at least one profile strip for fire protection glazing. These profile strips are known to the expert and are used as spacers in fire protection glazing. The corner connector comprises at least two plug-in legs and a connecting area that connects the two plug-in legs to each other. The two plug-in legs are suitable for being plugged into one end of a profile strip or plugged onto one end of a profile strip, thus creating a connection between the ends of at least one profile strip. The The connection area connects the two plug-in legs to one another and is not intended to be inserted into or plugged onto a profile strip. The corner connector comprises an outer surface, an inner surface and two side surfaces. In the finished fire-resistant glazing, the outer surface faces the environment and in the finished fire-resistant glazing, the inner surface faces the inner space between the panes. The side surfaces are the surfaces of the corner connector that face towards the panes of fire-resistant glazing. Along the plug-in legs, the side surfaces are in contact with the side surfaces of the spacer after being inserted into or plugged onto the spacer. When the plug-in legs are inserted into the spacer, the side surfaces of the spacer are in contact with the panes of the fire-resistant glazing. If the plug-in legs are plugged onto the spacer, the legs are in contact with the panes of the fire-resistant glazing. In the connection area, the corner connector protrudes from the spacer profiles so that the side surfaces in this area are in contact with the panes. The side surfaces in the connection area are intended so that the outer panes of the fire-resistant glazing can be attached there using a suitable sealant. The corner connector connects the ends of one or two profile strips that are assembled to form a spacer frame. The two plug-in legs are fixed in or on the profile strip(s) and are partially enclosed by them or partially enclose them. After the plug-in legs are connected to a profile strip, the side surfaces of the connection area and the outer surface of the connection area are exposed. The side surfaces are the surfaces that face the outer panes in the finished fire-resistant glazing and are arranged parallel to the outer panes of the fire-resistant glazing. The outer surface is the surface that faces the environment in the finished fire-resistant glazing. Depending on the desired geometry of the spacer frame, the two plug-in legs form different angles to each other, for example 10° to 180°. In a preferred embodiment, the plug-in legs form an angle of 90° to each other.

The plug-in legs are designed to be inserted into or onto a profile strip. Whether the corner connectors are inserted or plugged on is up to the specialist and can be selected depending on the geometry and nature of the profile strip. The principle for connecting the plug-in legs to the profile strips is that one of these two elements is designed as a receiving part (“female”) and the element connected to it is designed as an inserted part (“male”). In principle, a corner connector can also have one plug-in leg as a plug-in leg and one plug-in leg as a plug-on leg. However, the plug-in legs of a corner connector are preferably designed in the same way, whereby insertion legs or slip-on legs are selected depending on the geometry of the profile strip to be connected. If the profile strip is designed as a solid profile, for example, the insertion legs are preferably designed as slip-on legs that are plugged onto the profile strip. The slip-on legs thus comprise a receptacle that holds a section of the profile strip. For profile strips that are designed as a hollow profile with a closed or open cavity, corner connectors with insertion legs are preferred, whereby the insertion legs at least partially engage in the cavity of the profile strip. Mixed forms of insertion legs are also possible, which engage in a closed or open cavity of a profile strip and additionally have elements that surround the profile strip on its outer surfaces.

The corner connector is preferably designed to be rigid. This means that after the corner connector has been manufactured with an integrated recess with a backflow preventer, it can no longer be bent in the connection area. The angle a between the two plug-in legs can then no longer be changed significantly, i.e. by a maximum of 5°, preferably by a maximum of 1°, and particularly preferably not changed. This design improves the stability of the connector and prevents damage to the fastening of the backflow preventer in the connection area.

The backflow preventer used in the corner connector according to the invention can be designed in the form of a wide variety of commercially available backflow preventers, such as check valves or check flaps. The backflow preventer is preferably a slit valve, a duckbill valve, an umbrella check valve, a diaphragm check valve, a valve cone, a solenoid valve or a check flap. Backflow preventers of this type are commercially available. Valves and check flaps of this type close the recess as soon as the volume flow passing through the recess stops. Accordingly, the recess of the corner connector is automatically closed when the volume flow of the flowable fire protection compound stops and/or when a filling lance inserted through the backflow preventer of the recess is removed.

In a preferred embodiment, the non-return valve is designed as a slit valve. Slit valves are preferably designed as a diaphragm valve with a plastic diaphragm that has at least one notch. When a volume flow is applied, the fluid is pressed through the notch, whereby the plastic diaphragm bends in the direction of the volume flow. When the volume flow subsides, the diaphragm goes into its neutral starting position and closes the opening. Preferably, a plastic membrane with a cross-shaped cut is used. A slot valve is also suitable for inserting a filling lance through the slot of the valve into the space between the panes, whereby the plastic membrane rests against the pipe wall of the filling lance and minimizes or prevents the escape of fire protection compound during the filling process. In particular, a cross-slot valve is preferred to make it easier to insert a filling lance.

A particularly preferred embodiment of a slit valve is a so-called duckbill valve. This also comprises a plastic membrane, whereby the plastic membrane has a beak-shaped protuberance that opens into a slot. Duckbill valves have an improved restoring force of the membrane after deformation. The slot of the duckbill valve therefore closes particularly securely after the inserted filling lance has been removed. A good seal against escaping fire protection compound is also provided during the filling process.

In a further preferred embodiment, the backflow preventer is an umbrella check valve. This is formed by a movable cap, for example made of rubber or silicone, which folds over in the volume flow of the incoming fire protection compound like an umbrella in a storm, thereby opening the valve. A volume flow in the opposite direction pushes the movable cap in the opposite direction, thereby closing the recess. When filling using a filling lance, the movable cap of the umbrella check valve is pressed into the open position by the filling lance and swings back into the closed position after the filling lance is removed.

In a further embodiment of the invention, the backflow preventer is a diaphragm check valve, the diaphragm of which opens in the volume flow of the flowable fire protection compound or by inserting a filling lance and closes when the volume flow is in the opposite direction.

Furthermore, the backflow preventer can be designed as a valve cone. The conical wall of the cone has one or more openings, preferably a large number of openings, through which the flowable fire protection compound flows. The fire protection compound flows into the valve cone from the outside surface of the cone, with a membrane located on the inside of the cone being separated from the incoming fluid by the The cone surface is pushed away. This opens the valve. If the volume flow stops or the volume flow is in the opposite direction, the membrane is sucked back towards the inside of the cone, which closes the valve.

Furthermore, the backflow preventer can be designed as a solenoid valve. Suitable solenoid valves are commercially available. In one possible embodiment, the solenoid valve comprises a plate that is suitable for closing an opening. The plate and the area adjacent to the opening comprise a magnetic closure. The plate is arranged on the opening in such a way that a volume flow of fire protection compound into the space between the panes or an inserted filling lance lifts the plate and the fire protection compound flows into the chamber. If the volume flow stops or the filling lance is removed, the plate is pulled towards the opening and closes it.

In a further preferred embodiment, the backflow preventer is designed as a check valve. This check valve is preferably arranged on the inside of the corner connector in such a way that the check valve covers the recess. A movable part of the check valve is moved away from the recess by a volume flow passing through the recess or a filling lance inserted into the space between the panes. This movable part forms the actual flap part of the check valve. The flap part can be designed as a rigid element that is rotatably attached to one side of the recess and swings open when force is applied to the surface of the flap part facing the recess. A volume flow from the space between the panes towards the environment pushes the flap towards the recess and closes it. In a further preferred embodiment of the check valve, the movable flap part is designed as a flexible plastic membrane. This is preferably attached to the inside of the corner connector on one or both sides of the recess. The plastic membrane is movable in the area of the recess and is pushed away from the recess by a volume flow entering the space between the panes or by an inserted lance. If the filling lance is removed or the incoming volume flow stops, the plastic membrane moves back to the recess and closes it.

The recess is preferably placed in the connecting area between the two plug-in legs. The recess is to be arranged in a space-saving manner in the connecting area between the plug-in legs. In addition, filling the flowable Fire protection compound at the corner of the fire-resistant glazing is advantageous to prevent blistering.

In a preferred embodiment of the corner connector, the recess with backflow preventer is continuous for flowable fire protection compounds in a flow direction starting from the environment in the direction of the space between the panes over a total area of at least 0.5 mm ² , preferably of at least 1 mm ² , particularly preferably of at least 2 mm ² , in particular of at least 5 mm ² . The flow direction from the environment into the space between the panes is defined in relation to the installation situation of the corner connector in fire-resistant glazing. In the finished fire-resistant glazing, the outer surface of the corner connector faces the environment and the inner surface in the finished fire-resistant glazing faces the inner space between the panes, so that during the filling process, the recess is flowed through from the outer surface of the corner connector in the direction of the inner surface. By means of the total areas mentioned, the flow cross-section when filling with flowable fire protection compound is improved.

In one possible embodiment of the corner connector according to the invention, the connection area protrudes in relation to the plug-in legs. The projection U between the outer surface of the connection area and the outer surface of the plug-in legs is 0.5 mm to 10 mm, preferably 1 mm to 5 mm and particularly preferably 1 mm to 4 mm, for example 2.5 mm. By enlarging the connection area, the stability of the connector is increased and the installation space for the backflow preventer is increased.

In a preferred embodiment of the corner connector, it is manufactured using an injection molding process. The plug-in legs and the connection area are injection molded. The backflow preventer is either integrated directly during the injection molding process or subsequently inserted into the recess or adjacent to the recess. After the injection-molded material has hardened, the finished corner connector can be removed from the injection molding tool and the backflow preventer can be inserted if it has not already been integrated.

In a further preferred embodiment of the corner connector according to the invention, the recess on the outer surface of the corner connector is covered. The cover closes the recess with a backflow preventer inserted therein against the ingress of dirt or secondary sealing agent, which can optionally be used when sealing the fire-resistant glazing. The cover can, for example, snapped in, clicked in, screwed in via a thread or formed by a rubber cap inserted into the recess.

The corner connector is preferably made of polymers, as these have a low thermal conductivity, which leads to improved thermal insulation properties of the edge connection. The connector particularly preferably contains biocomposites, polyethylene (PE), polycarbonates (PC), polypropylene (PP), polystyrene, polybutadiene, polynitriles, polyesters, polyurethanes, polymethyl methacrylates, polyacrylates, polyamides, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyvinyl chloride (PVC), particularly preferably acrylonitrile-butadiene-styrene (ABS), acrylester-styrene-acrylonitrile (ASA), acrylonitrile-butadiene-styrene/polycarbonate (ABS/PC), styrene-acrylonitrile (SAN), PET/PC, PBT/PC and/or copolymers or mixtures thereof.

In one possible embodiment, the polymer corner connector is fiber-reinforced. The corner connector preferably has a fiber content of 5% to 65%, particularly preferably 20% to 60%. The fiber content in the corner connector according to the invention improves strength and stability. By choosing the fiber content, the thermal expansion coefficient of the corner connector can be varied and adapted to the hollow profile spacer. Natural fibers or glass fibers, particularly preferably glass fibers, are preferably used to reinforce the corner connector.

In an alternative design, the corner connector can also be made of metal.

In addition to the features described, the corner connector can include further features, for example elements for fixing the plug-in legs in the spacer. For this purpose, the plug-in legs can have slats or wire elements that enable better fixing of the plug-in legs in the spacer. Alternatively or additionally, the corner connector can be equipped with fixing elements. If the plug-in legs are designed as plug-in legs, the fixing elements extend, for example, from the connection area at a distance from the outer surface of the plug-in legs parallel to the legs. The spacer profile plugged onto the plug-in legs encloses the outer surface of the plug-in legs, with the fixing elements resting on the surface of the spacers facing away from the leg and securing them in position. In other words, the spacer profile engages in the corner connector between the fixing element and the plug-in leg, with the plug-in leg being at least partially enclosed by the spacer profile. The corner connector according to the invention can be designed as a single or multiple corner connector. A single corner connector comprises two plug-in legs, each of which accommodates a profile strip. A multiple corner connector, on the other hand, has at least four plug-in legs, half of which run parallel to each other. In the connection area, the multiple corner connector has a web from which all legs of the corner connector extend. In a preferred embodiment, the corner connector according to the invention is designed as a double corner connector. This has four plug-in legs, two of which are arranged parallel to each other. Such a double corner connector preferably contains one or more recesses that contain backflow preventers.

A further aspect of the invention relates to fire-resistant glazing comprising at least one corner connector according to the invention. The fire-resistant glazing comprises at least one first pane, a second pane arranged parallel to it and a surrounding spacer frame arranged between the panes. The spacer frame comprises at least one profile strip and at least one corner connector according to the invention. An inner space between the panes, also referred to as a chamber, is formed between the first pane, second pane and spacer frame, into which a fire-resistant layer is introduced. The at least two plug-in legs of the corner connector according to the invention are inserted into the ends of the at least one profile strip.

The spacer frame can comprise one or more individual profile strips that are put together to form a complete frame. The individual strips can be welded together, glued together or connected together using connectors. The profile strip can also be made continuously and bent at the corners. The ends of the profile strip are connected at at least one point using a corner connector according to the invention. The spacer frame is preferably rectangular. Most fire-resistant glazing is made in this shape.

The spacer frame can be formed by a profile strip which is bent into a frame and whose two ends are connected by a corner connector according to the invention. A spacer frame can also be composed of a profile strip which is interrupted into several strips, with at least two individual strips being connected by a corner connectors according to the invention and the remaining strips are connected using corner connectors according to the state of the art.

The spacer frame preferably contains a corner connector according to the invention with a backflow preventer, a corner connector with a vent opening and two corner connectors according to the prior art without a vent opening or recesses. The corner connector with a backflow preventer and the corner connector with a vent opening are preferably attached to two opposite corners in order to achieve an optimal filling process. The corner connector with a vent opening preferably has a recess as a vent opening through which air can escape from the space between the panes during the filling process. A vent pipe is particularly preferably inserted into the recess. Alternatively or in addition to the vent pipe, a backflow preventer is preferably inserted into the vent opening. The backflow preventers used in the corner connector according to the invention are suitable, wherein the installation direction of the backflow preventer in the ventilation opening is selected such that a volume flow from the space between the panes towards the environment opens the backflow preventer and a volume flow from the environment into the space between the panes is prevented.

An embodiment of a spacer frame without a ventilation opening is also within the scope of the invention, in which case the air escapes during the filling process via the recess of the corner connector according to the invention.

The profile strips, also called spacers, comprise at least a first pane contact surface, a second pane contact surface arranged parallel thereto, an outer wall arranged perpendicular to the pane contact surfaces and optionally an inner wall, also referred to as the glazing interior wall. The outer wall is arranged essentially parallel to the glazing interior wall and connects the side walls to one another.

Profile strips for fire-resistant glazing are known to those skilled in the art, with both rigid or flexible polymer profile strips and strand-like extruded flexible profiles being common.

Flexible profiles extruded in strands are made from a sealant and are also referred to as thermoplastic spacers. These are preferably They are designed as a solid profile and preferably comprise a sealant from the group of hot melt adhesives, preferably from the group of butyl-based hot melt adhesives, preferably butyl rubber and/or polyisobutylene. Other suitable sealants are known to the person skilled in the art from applications for thermoplastic spacers (TPS). Such spacers can be extruded directly onto one of the panes of the fire-resistant glazing or can also be provided as a prefabricated strand that is glued between the panes using a primary sealant. Such profile strips are preferably combined with corner connectors with clip-on legs.

In a preferred embodiment, the profile strips are designed as rigid or bendable polymer profiles. These prove to be particularly advantageous in the production process of fire-resistant glazing in order to prefabricate a spacer frame and to glue the prefabricated frame between the panes. Such profile strips are known in the art and comprise at least a first pane contact surface, a second pane contact surface arranged parallel to it, an outer wall arranged perpendicular to the pane contact surfaces and optionally an inner wall, also referred to as the glazing interior wall. The outer wall is arranged essentially parallel to the glazing interior wall and connects the side walls to one another. The glazing interior wall, if present, preferably has a recess so that the profile strip is open on this surface. In a preferred embodiment, the first pane contact surface, the second pane contact surface and the outer wall enclose a cavity that is open towards the space between the panes. Embodiments with a cavity are particularly suitable for combination with corner connectors with insertion legs, which engage in the cavity of the profile strip.

The profile strips are preferably shaped in the form of the letter H, W or I, particularly preferably in the form of a letter C or U. Profile strips with closed or half-open cavities are particularly suitable for combination with corner connectors with insertion legs. For example, a U-shaped profile strip encompasses the outer surface and at least parts of the side surfaces of the corner connector. C-shaped profile strips are advantageous in that they encompass the outer surface, the side surfaces and part of the inner surface of the corner connector and thus enable improved fixing. The inner surface of the corner connector remains at least partially exposed. The interior wall of the profile strips, also referred to as the glazing interior surface, is preferably at least partially recessed so that the fire protection compound fills the cavity of the profile strips. The first pane contact surface and the second pane contact surface of the profile strip are intended for the first pane and the second pane to be fastened there. The first pane and the second pane are preferably fastened to the first pane contact surface or to the second pane contact surface using a primary sealant. The spacer frame is preferably prefabricated and then fastened between the first pane and the second pane using a primary sealant. This ensures that the inner space between the panes is well sealed from the outside environment. This prevents moisture from penetrating. The primary sealant preferably contains a polyisobutylene. The polyisobutylene can be a cross-linking or non-cross-linking polyisobutylene.

In a further embodiment, the primary sealing means comprises other fastening means known to those skilled in the art for fixing the panes to the first and second pane contact surface. These include, for example, the double-sided foam adhesive tapes commercially available under the term structural glazing tape comprising a pressure-sensitive polymer foam and acrylate adhesive. Furthermore, transparent double-sided acrylate adhesive tapes are also known and suitable for this purpose.

As an alternative to bonding with a primary sealant, profile strips made of strand-like extruded sealants can also be injected directly onto or between the panes.

The inner space between the panes is delimited by the first pane, the second pane and the profile strip. The outer wall of the profile strip and the first and second panes preferably delimit an outer space between the panes. The surrounding outer space between the panes is preferably filled with an outer seal, known as a secondary seal, adjacent to the surrounding sealant. This outer seal serves primarily to bond the two panes together and thus to ensure the mechanical stability of the glazing.

The secondary sealant preferably contains polysulfides, silicones, silicone rubber, polyurethanes, polyacrylates, copolymers and/or mixtures thereof. Such substances have very good adhesion to glass, so that the outer seal ensures secure bonding of the panes. The thickness of the outer seal made of secondary sealant is preferably 2 mm to 30 mm, particularly preferably 3 mm to 10 mm. Preferably the secondary sealant is flush with the peripheral edge of the first pane and the second pane.

Preferably, after the cavity between the panes has been filled with the fire protection compound, the secondary sealant is introduced into the outer cavity between the panes on the surface of the surrounding sealant facing the environment.

Various types of fire protection glass are known in the prior art that use flowable fire protection compounds, for example water-containing alkali silicates or water-containing hydrogels. After curing, such fire protection compounds produce a fire protection layer that becomes cloudy, foams, heat-insulates and/or cools when exposed to heat. The flowable fire protection compound preferably comprises at least alkali silicates and at least one hardener. After the fire protection compound has cured, a fire protection layer is thus formed. Such fire protection layers have good transparency under normal conditions, while in the event of a fire a heat protection effect is achieved by the fire protection layer becoming cloudy and foaming. Foaming fire protection layers are also referred to as intumescent fire protection layers and are known to those skilled in the art. A wide variety of intumescent or non-intumescent fire protection compounds known to those skilled in the art can be used as the fire protection layer. The fire protection layer preferably comprises polysilicates or hydrogels. By way of example, the alkali silicates mentioned in EP 2516568 B1 and the hydrogels described in DE 102005018842 A1 are suitable. Alkali silicate gels according to EP 3224045 A1 have proven to be particularly advantageous. Hydrogels have proven to be particularly advantageous in the implementation of the invention due to the good flowability of such fire protection compounds.

In one possible embodiment of the method, fire protection glazing comprises additional panes extending beyond the first pane and the second pane, which are also connected to these panes via a spacer frame, analogous to the connection between the first pane and the second pane. In this way, two or more chambers are formed in the gaps between the panes, which are to be filled with fire protection compound. The chambers can be filled one after the other or simultaneously. Preferably, such multi-chamber glazings, also known as multi-layer modules, are filled in such a way that all chambers are filled at the same time. On the one hand, this is advantageous in terms of a short cycle time. On the other hand, the Plane parallelism of the glass panes is ensured by simultaneously filling adjacent chambers.

The first pane and/or the second pane, and optionally further panes, preferably contain glass, particularly preferably quartz glass, borosilicate glass, soda-lime glass and/or mixtures thereof. The panes can also comprise thermoplastic polymer panes. Thermoplastic polymer panes preferably comprise polycarbonate, polymethyl methacrylate and/or copolymers and/or mixtures thereof.

The first pane and the second pane have a thickness of 1 mm to 50 mm, preferably 1 mm to 10 mm, particularly preferably 2 mm to 6 mm, whereby both panes can also have different thicknesses. Panes of fire-resistant glazing that extend beyond this are preferably also in these thickness ranges.

The first pane, the second pane and optionally further panes can be made of single-pane safety glass, thermally or chemically toughened glass, float glass, extra-clear low-iron float glass, colored glass or laminated safety glass containing one or more of these components. The panes can have any other components or coatings, for example low-E layers or other solar protection coatings.

The fire-resistant glazing according to the invention is preferably used as building glazing, facade glazing, partition wall, floor glazing, ceiling glazing, window or door glazing, as vehicle glazing or ship glazing, each individually or as part of a laminated glass or an insulating glazing.

Furthermore, the invention comprises a method for producing fire-resistant glazing comprising at least the steps: a) providing a first pane and a second pane, b) attaching a spacer frame with at least one corner connector according to the invention all the way around the edge region between the first pane and the second pane by means of a primary sealant and producing a ventilation opening in the spacer frame, c) pressing the arrangement of the first pane, second pane and spacer frame together to form a space between the panes between the first pane, second pane and spacer frame, d) introducing a flowable fire protection compound through the recess of the corner connector according to the invention into the space between the panes, whereby air escapes through the ventilation opening, e) closing the ventilation opening and f) hardening the flowable fire protection compound in the space between the panes to form fire-resistant glazing.

The filling process according to the invention enables the chamber to be filled with fire protection compound in an essentially bubble-free manner.

Optionally, the pressure in the space between the panes can be reduced by at least partially removing the air in the chamber by applying a negative pressure to the ventilation opening, whereby fire protection compound flows into the chamber through the corner connector according to the invention.

Manual handling of the glazing, such as tilting and swiveling the glazing for uniform, bubble-free filling, is not required in the filling process according to the invention. This eliminates such manual steps while maintaining consistent product quality.

After the spacer frame has been inserted using a primary sealant, the first pane and the second pane are pressed together. Suitable presses, for example for the production of insulating glazing, are known to those skilled in the art. After the arrangement has been pressed together, the space between the panes and the spacer forms a chamber that can be filled with fire protection compound.

The next step is to fill the chamber with a fire protection compound. According to the state of the art, a lance is usually inserted into the chamber through a recess in the sealant strand and the fire protection compound flowing out of the lance is evenly distributed in the chamber by tilting the blank, whereby the air displaced by the fire protection compound escapes through the recess. The occurrence of air pockets is monitored manually by a production employee and these are released if necessary by shaking the blank, for example by hitting it with a rubber hammer. Using the method according to the invention, fire protection glazing of various geometries can be filled, whereby these have at least one corner connector according to the invention. The majority of fire protection glazing requested by customers has a rectangular geometry. If the fire protection glazing has several corners, the chamber is preferably filled via these corners, whereby the corner connector according to the invention with backflow preventer is provided at one corner and the ventilation opening is provided at the diagonally opposite corner. This is advantageous in order to further facilitate the gap-free filling of the corner areas with fire protection compound.

The fire protection glazing is preferably oriented during the filling process such that the distance of the corner connector according to the invention with backflow preventer from the floor surface on which the filling system is positioned is smaller than the distance of the ventilation opening from the floor surface. In other words, the corner connector according to the invention is located below the ventilation opening, whereby these do not have to lie within a line perpendicular to the floor surface. The glazing is thus arranged during the filling process such that the filling direction in which the fire protection compound flows in during the filling process has a directional component that is opposite to the weight force. In simple terms, the chamber is filled from bottom to top, with "bottom" referring to the edge of the glazing closest to the floor surface on which the filling system is positioned. This filling direction is particularly advantageous for removing air residues from the chamber to be filled. Filling from above, on the other hand, would lead to increased air inclusions. The fire protection compound would be filled into an upper recess and flow downwards in the chamber, causing air turbulence and trapping air bubbles in the fire protection compound. This is prevented by the method according to the invention.

Preferably, the blank is arranged during the filling process such that the surfaces of the first disc and the second disc form an angle of 10° to 90°, preferably 30° to 90°, to a parallel to the floor surface on which the filling system is positioned. In this way, air residues are effectively displaced, rise and escape via the ventilation opening or are sucked out via this.

In step d), the fire protection compound is preferably introduced into the space between the panes via a pipe. The term pipe describes an elongated hollow body that is suitable for supplying the fire protection compound. The pipe can, for example, have a rigid or flexible wall, a round, oval or square cross-section and is placed in the recess of the corner connector according to the invention during the filling process, preferably introduced into the chamber through the backflow preventer of the corner connector. A filling lance is particularly preferably used. This is advantageous in order to ensure clean, loss-free filling.

The pipe or the filling lance for filling the chamber is in contact with a volume of the fire protection compound and directs this into the chamber. The volume of the fire protection compound for filling is preferably located in a storage container. Fire protection compound is fed from the storage container into the chamber until it is completely full. To ensure complete filling, overfilling the chamber is preferred, with the excess fire protection compound emerging from the vent opening preferably being directed back into the storage container. Another preferred option is to monitor the fill level of the storage container. The volume of the chamber to be filled is calculated from the pane surfaces and the width of the spacer frame, which makes it possible to determine how much fire protection compound has to be taken from the storage container. This method has the advantage that the chamber does not have to be overfilled. In a preferred embodiment of the method according to the invention, the storage container has a fill level sensor and/or is positioned on a scale. In a further preferred embodiment of the method, the fill level is monitored by a flow sensor that is installed between the storage container and the filling lance, for example in a hose section or in the filling lance itself. In comparison to overfilling the chamber, there is no need to return or dispose of excess fire protection compound that escapes from the vent opening.

Preferably, the chamber is evacuated via the vent opening, for which embodiments of the fire protection glazing according to the invention are particularly suitable, the vent opening of which is integrated in a corner connector with a vent pipe. In this case, a negative pressure is applied to the vent pipe, for example by bringing the vent pipe into contact with the supply line of a vacuum pump and sucking out the gases in the chamber. The negative pressure to be set depends, for example, on the size of the pane and also has to be adjusted during the filling process. For example, a lower negative pressure is generally required at the beginning of the filling process than towards the end of the filling process. A negative pressure applied to the vent opening is particularly advantageous to prevent the discs from bulging during the filling process. Furthermore, the formation of bubbles is reduced.

The chamber filled with flowable fire protection compound is then subjected to a curing step, whereby the flowable fire protection compound hardens. For example, polymerization takes place so that a fire protection gel forms in the chamber. The method according to the invention can be used for all fire protection compounds that can be processed in a flowable form during the production process and harden in a subsequent step.

In a preferred embodiment of the method according to the invention, the first pane and the second pane are fixed to one another during filling of the chamber. This is preferably done by fixing the surfaces of the first pane and the second pane facing away from the chamber. The surfaces of the first pane and the second pane facing away from the chamber represent the surfaces of the glazing facing the environment, which are thus accessible from the environment. The panes are fixed by means of measures known to those skilled in the art, such as plates, frames, rollers and/or suction devices. The glazing is preferably positioned on a frame, for example the pane holder of a continuous production line, the surface of the first or second pane being fixed at least in places by the frame. The remaining exposed pane surface of the first or second pane is preferably fixed at least in places by a suction device placed on this pane surface. In this way, the first pane and the second pane are held rigidly to one another, so that bulging or sagging of the panes is prevented during the filling process. The suction device placed on the pane surface is particularly preferably used to rotate the glazing into a preferred filling position before filling. Preferred filling positions are those already described, with the corner with the corner connector according to the invention and the corner with the ventilation opening being arranged in opposite corners and the glazing being rotated so that the corner connector according to the invention forms the lowest point, i.e. represents the section of the glazing closest to the bottom surface of the filling system.

Preferably, the glazing is vibrated during and/or after filling with fire protection compound, especially during filling, but in any case before the fire protection compound hardens. This will loosen any air bubbles that may be present, cause them to rise upwards towards the ventilation opening and be sucked out. Such additional Measures to remove air bubbles are generally not necessary, but can be useful for particularly large pane dimensions. In a preferred embodiment of the method, the glazing is set into vibration by means of a vibration unit attached to a gripper arm. In particular, a vibration unit can be attached directly to the arm of a suction device with which a surface of the first pane or second pane is fixed.

In step d) of the process, the fire protection compound is preferably filled under a pressure that is higher than the ambient pressure. This is advantageous in order to increase the filling speed in the process, which can be particularly helpful with large pane dimensions. The fire protection compound is particularly preferably filled at a pressure above the ambient pressure. The fire protection compound is preferably filled using a pump.

The invention is explained in more detail below using drawings and exemplary embodiments. The drawings are purely schematic representations and not to scale. The drawings do not limit the invention in any way.

Show it:

Figures 1a, 1b show a schematic representation of a fire protection glazing with a corner connector according to the invention with a backflow preventer during the filling process with a flowable fire protection compound,

Figure 2 is a schematic representation of a corner connector according to the invention in cross section with a duckbill valve inserted in a recess,

Figure 3 is a schematic representation of another embodiment of the corner connector according to the invention in cross section with a Phillips valve inserted in a recess,

Figure 4 is a schematic representation of a top view of the corner connector according to the invention with fixing elements,

Figures 5 to 8 are schematic representations of various embodiments of the backflow preventers in the corner connector according to the invention,

Figure 9 shows an embodiment of a corner connector according to the invention with a non-return valve,

Figure 10 is a schematic representation of a profile strip of the fire protection glazing according to the invention, Figure 11 is a schematic representation of a fire protection glazing according to

Figures 1a and 1b, which is fixed on a production line by a robot arm and filled according to process step d),

Figure 12 shows a fire-resistant glazing according to the invention produced using the method according to the invention.

According to the figures, the plug-in legs are designed as plug-in legs, but a design as plug-on legs is also possible.

Figures 1a and 1b show a schematic representation of a fire-resistant glazing II during the filling process according to method step d) of the method according to the invention. Figure 1a shows a top view, while Figure 1b shows a cross section along the section line AA' according to Figure 1a. The fire-resistant glazing II comprises a first pane 13 and a second pane 14, which are connected to one another via a circumferential spacer frame 8 attached between the panes 13, 14. The spacer frame 8 is glued to the first pane 13 and the second pane 14 via a primary sealant, the spacer frame 8 being set back from the circumferential edge K of the first pane 13 and the second pane 14 by 5 mm in the direction of the center of the surface of the first pane 13 and the second pane 14. The spacer frame 8 and the panes 13, 14 enclose a chamber in the space between the panes 12. The outer pane space 9 is located on the surface of the spacer frame 8 facing away from the pane space 12 and facing the environment. This is enclosed on three sides by the first pane 13, the second pane 14 and the spacer frame 8 and is open to the environment on a fourth side. The fire-resistant glazing II has a rectangular geometry, with a corner connector I according to the invention with a backflow preventer 32 inserted in a recess 33 being inserted into the spacer frame 8 at one corner of the fire-resistant glazing II and a corner connector 62 with a ventilation opening 60 and a ventilation pipe 61 installed therein being inserted at the opposite corner. A filling lance (not shown here) is introduced into the space between the panes 12 through the backflow preventer 32 of the corner connector I in order to fill the fire protection glazing II with a flowable fire protection compound 6a, whereby the flow direction of the fire protection compound 6a is indicated as flow direction F. The flowable fire protection compound 6a comprises hydrogels. The flow direction F of the two fluids, fire protection compound and air, is shown by means of arrows. Figure 2 shows a corner connector I according to the invention with a recess 33 and a backflow preventer 32 inserted therein. The illustration is greatly simplified. Slats or retaining elements, such as can be used to fix the corner connectors in a profile strip, are not shown, for example. These can be added by a person skilled in the art as required. The corner connector I comprises two plug-in legs 31 which are connected to one another in the connecting area 34. According to this embodiment, the two plug-in legs 31 enclose an angle a (alpha) of 90° and are designed as plug-in legs. The corner connector I has an outer surface 39 which, in the finished fire-resistant glazing II, faces the environment and an inner surface 41 which, in the finished fire-resistant glazing II, faces the inner space between the panes 12. A recess 33 is integrated in the connecting area 34. A backflow preventer 32 is inserted into the recess 33. The backflow preventer 32 is a duckbill valve, the slot opening of which protrudes into the space between the panes 12. The duckbill valve is shown in detail in Figure 5. The plug-in legs 31 and the connecting area 34 are manufactured in one piece from a polymer using an injection molding process. The connecting area 34 protrudes compared to the plug-in legs 31. The overhang U between the outer surface 39 of the plug-in legs 31 and the outer surface 39 of the connecting area 34 is 2.5 mm. The connecting area 34 also protrudes slightly in relation to the side surfaces 40 of the plug-in legs 31 (not visible here, see Figure 4). The size of this overhang depends on the profile strip 1 to be used. Preferably, the profile strip 1 in the fire-resistant glazing II is flush with the side surfaces 40 of the connecting area 34. The protruding connection area 34 has the additional advantage that it reinforces the connection area 34, which contributes to increasing the stability of the connector I. The exact dimensions of the corner connector I depend on the profile strips 1 used. In the example, the length L of a plug-in leg is 3.2 cm, and the length E of the connection area is approximately 1.2 cm.

Figure 3 shows a further embodiment of the corner connector I according to the invention. This essentially corresponds to the embodiment of Figure 2, with the difference that a slit valve according to Figure 6 is inserted into the recess 33.

Figure 4 shows a schematic representation of a top view of the corner connector I according to the invention with fixing elements 42. The corner connector I essentially corresponds to that described in Figure 2, with two fixing elements 42 additionally being attached to each plug-in leg 31, which extend parallel to the connecting area 34. to the outer surfaces 39 of the plug-in legs 31 in the direction of the end faces 35 of the plug-in legs 31. The corner connector I contains a backflow preventer according to one of Figures 5 to 8.

Embodiments of the backflow preventers 32 inserted into the recess 33 of the corner connector I according to Figures 2 to 4 are shown in Figures 5 to 8. The backflow preventers 32 as such are commercially available. The flow direction F of the backflow preventers 32 is indicated with an arrow. Figure 5 shows a duckbill valve 51. Due to the high restoring force of the slot opening 59, this is particularly suitable as a backflow preventer 32. A filling lance is preferably introduced in the flow direction F through the duckbill valve 51 into the space between the panes 12. Figure 6 shows a slot valve 52 with a cross-shaped slot opening 59. When using the slot valve 52, no flow direction F needs to be observed. Furthermore, the slit valve 52 is well suited for inserting a filling lance through the slit opening 59. Figure 7 shows an umbrella check valve 53 comprising a base plate 53.1, a flexible cover cap 53.2 and openings 53.3 which are introduced into the base plate below the cover cap 53.2, wherein a volume flow in the flow direction F through the openings 53.3 leads to the cover cap 53.2 folding over from the closed state a) to the open state b). Figure 8 shows a valve cone 54, the conical surface of which has a plurality of openings 54.1. A membrane 54.2 rests on the inner surface of the cone and is pushed to the side by the incoming fluid when the valve cone 54 flows in the flow direction F.

Figure 9 shows a check valve 55 which is fitted as a backflow preventer 32 adjacent to the recess 33 on the inner surface 41 of a plug-in leg 31 of the corner connector I. A filling lance can be introduced through the check valve 55 in the direction of flow F directly into the space between the panes 12. The check valve 55 is pushed to the side (state b)). After the filling lance is removed, the reset valve 55 returns to the closed position (state a)).

Figure 10 shows a perspective cross-section of an embodiment of a profile strip 1. The profile strip 1 comprises two parallel pane contact surfaces 2.1 and 2.2, which establish contact with the panes 13 and 14 of a fire-resistant glazing II. The pane contact surfaces 2.1 and 2.2 are connected via an outer wall 4 and an interior wall 3. The outer wall 4 runs essentially parallel to the interior wall 3. The profile strip 1 is made of a polymer and additionally glass fiber reinforced and contains, for example, styrene-acrylonitrile (SAN) and about 35% by weight of glass fiber. The profile strip 1 has a cavity 5 and the wall thickness of the polymer hollow profile 1 is, for example, 1 mm. The interior wall 3 is not continuous, so that the fire protection compound 6a can enter the cavity 5. Such C- or U-shaped profile strips are preferred because corner connectors with insertion legs can be easily inserted into the cavities of the profile strips and profile strips and corner connectors together form a spacer frame that is easy to handle in the manufacturing process.

Figure 11 shows a section of a production line 15 for the manufacture of fire-resistant glazing II as a schematic representation, in which the filling of the fire-resistant glazing II with fire-resistant compound 6a is shown. The fire-resistant glazing

11 corresponds to that described in Figures 1a and 1b. The fire-resistant glazing II is grasped in this section of the production line 15 by a robot arm 16 with a suction device that rests against an exposed surface of one of the panes 13, 14. The fire-resistant glazing II is first rotated by means of the robot arm 16 so that the corner connector I is closest to the floor area on which the production line 15 is arranged. A filling lance 17 is then inserted through the corner connector I into the space between the panes.

12, and fire protection compound 6a is introduced through the filling lance 17, whereby air escapes from the space between the panes 12 via the corner connector 62 with ventilation pipe. The orientation of the fire protection glazing II according to Figure 11 is particularly advantageous in order to avoid air inclusions. The flow direction F of the fire protection compound 6a is indicated with an arrow. During the filling process, the panes 13, 14 are fixed between the robot arm 16 and the section of the production line 15 in such a way that bending of the panes during the filling process is prevented.

Figure 12 shows a fire-resistant glazing II according to the invention produced using the method according to the invention. The fire-resistant glazing II corresponds to that described in Figures 1a, 1b, whereby the space between the panes 12 was completely filled with fire-resistant compound 6a and this was cured. This results in the fire-resistant layer 6. The outer space between the panes 11 is sealed with polysulfide as a secondary sealant 10. List of reference symbols:

(I) Corner connector

(II) Fire-resistant glazing

(I) Profile strip, spacer

(2.1) first disc contact surface

(2.2) second disc contact surface

(3) Interior wall, glazing interior surface

(4) Exterior wall

(5) Cavity

(6) Fire protection layer

(6a) Fire protection compound

(8) Spacer frame

(9) primary sealant

(10) secondary sealant

(I I) outer space between panes

(12) Interpane space, chamber

(13) first disc

(14) second disc

(15) Production line

(16) Robot arm

(17) Filling lance

(31) Plug-in legs

(32) Backflow preventer

(33) Recess

(34) Connection area

(39) Exterior surface

(40) Side surfaces

(41) Inner surface

(42) Fixing elements (51) Duckbill valve

(52) Slot valve

(53) Umbrella check valve

(53.1) Base plate

(53.2) flexible cover cap

(53.3) Openings

(54) Valve cone

(54.1) Openings

(54.2) Membran

(55) Check valve

(59) Slot opening

(60) Vent opening

(61) Vent pipe

(62) Corner connector with ventilation opening

K common peripheral edge of the first disc 1 and the second disc 2

F Flow direction

AA‘ cutting line

Claims

Patent claims

1. Corner connector (I) for connecting two ends of at least one profile strip in fire-resistant glazing, comprising two plug-in legs (31) suitable for insertion into or plugging onto a profile strip (1), a connecting region (34) which connects the two plug-in legs (31), an outer surface (39), two side surfaces (40) and an inner surface (41), wherein

- a recess (33) is provided in the corner connector (I) which is suitable for creating a passage from the environment to the inner space between the panes (12) in a fire-resistant glazing (II) and

- a backflow preventer (32) is inserted into the recess (33) or adjacent to the recess (33), which is suitable for allowing the flow of a flowable fire protection compound through the recess (33) from the environment into the space between the panes (12) and for preventing the backflow of a flowable fire protection compound through the recess (33) from the space between the panes (12) towards the environment.

2. Corner connector (I) according to claim 1, wherein the backflow preventer (32) is a slit valve, a duckbill valve, an umbrella check valve, a diaphragm check valve, a valve cone or a check valve.

3. Corner connector (I) according to claim 1 or 2, wherein the recess (33) is introduced into the connecting region (34) between the two plug-in legs (31).

4. Corner connector (I) according to one of claims 1 to 3, wherein the recess (33) with backflow preventer (32) on a total area of at least 0.5 mm ² , preferably of at least 1 mm ² , particularly preferably of at least 2 mm ² , enables the flow of a flowable fire protection compound through the recess (33) from the environment into the space between the panes (12).

5. Fire-resistant glazing (II) at least comprehensive

- a first disc (13) and a second disc (14),

- a circumferential ring arranged between the discs (13, 14)

Spacer frame (8) comprising at least one profile strip (1) and at least one corner connector (I) according to one of claims 1 to 4, - an inner space between the panes (12) delimited by the spacer frame (8) and the two panes (13, 14),

- the at least two plug-in legs (31) of the corner connector (I) are inserted into or onto the ends of the at least one profile strip (1), and

- a fire protection layer (6) is installed in the inner space between the panes (12).

6. Fire-resistant glazing (II) according to claim 5, wherein the at least one profile strip (1) has at least one first pane contact surface (2.1); a second pane contact surface (2.2) arranged parallel thereto and an outer wall (4) which connects the pane contact surfaces (2.1, 2.2) to one another; and optionally has an interior wall (3), and wherein preferably the interior wall (3) of the at least one profile strip (1) is not continuous between the two pane contact surfaces (2.1, 2.2).

7. Fire-resistant glazing (II) according to claim 5 or 6, wherein the fire-resistant layer (6) comprises at least one hydrogel.

8. Fire-resistant glazing (II) according to one of claims 5 to 7, wherein the fire-resistant glazing (II) comprises at least one ventilation opening (60) which is suitable for allowing the escape of air during the filling process of the fire-resistant glazing (II) with a fire protection compound (6a), and wherein the ventilation opening (60) is preferably arranged at the corner of the fire-resistant glazing (II) opposite the corner connector (I).

9. Fire-resistant glazing (II) according to claim 8, wherein the ventilation opening (60) is designed as an opening in the connection region of a corner connector and preferably comprises a ventilation pipe which points from the corner connector towards the environment and particularly preferably the ventilation opening is formed by a recess (33) of a corner connector with a backflow preventer.

10. Method for producing a fire-resistant glazing (II) according to one of claims 5 to 9, wherein a) a first pane (13) and a second pane (14) are provided, b) in the edge region between the first pane (13) and the second pane (14) a spacer frame (8) with at least one corner connector (I) is attached by means of a primary sealing means (9) and a ventilation opening (60) is provided in the spacer frame (8), c) the arrangement of the first pane (13), second pane (14), spacer frame (8) and sealant (9) is pressed together, whereby a gap (12) is created between the first pane (13), second pane (14) and spacer frame (8), d) a flowable fire protection compound (6a) is introduced into the gap (12) between the panes through the recess (33) of the corner connector (I), whereby the air from the gap (12) escapes through the ventilation opening (60), e) the ventilation opening (60) is closed and f) the flowable fire protection compound (6a) hardens in the gap (12) between the panes and the fire-resistant glazing (II) is obtained.

11. The method according to claim 10, wherein the vent opening (60) is introduced at the corner opposite the corner connector (I) with backflow preventer (32).

12. The method according to claim 10 or 11, wherein in step d) the surface of the first disc (13) and the second disc (14) form an angle of 10° to 90°, preferably 30° to 90°, particularly preferably 40° to 85°, to the bottom surface of the filling system and the distance of the corner connector (I) to the bottom surface of the filling system is less than the distance of the vent opening (60) to the bottom surface of the filling system.

13. Method according to one of claims 10 to 12, wherein the fire protection compound (6a) in step d) is introduced into the space between the panes (12) via a pipe (8), preferably via a filling lance, and the filling lance is particularly preferably introduced into the space between the panes (12) through the recess of the corner connector (I).

14. Method according to one of claims 10 to 13, wherein the fire protection compound (6a) is filled in step d) under a pressure which is higher than the ambient pressure.

15. Method according to one of claims 10 to 14, wherein the flowable fire protection compound (6a) comprises at least hydrogels and at least one hardener.