Apparatus for producing insulating glass filled with a gas other than air
This invention relates to apparatus for producing insulating glass filled with a gas other than air such as sulfur hexafluoride, from uncompacted insulating glass comprising two substantially vertical plates disposed on opposite sides of the insulating glass to be filled with the gas, e.g., platens operable to compact insulating glass, at least one of which plates is displaceable transversely to its plane. 
     To fill insulating glass with heavy gas, narrow tubes were previously used, which were introduced into the interior of insulating glass through holes in the spacer frame of compacted insulating glass. The heavy gas was injected through said tubes under pressure and at a high velocity of flow. That known operation is not desirable because holes are required which when the glass has been filled with heavy gas must be sealed in a troublesome operation and because the insulating glass cannot be completely filled with heavy gas within a reasonable time but a mixture of heavy gas and at least 30% air usually results. It is an object of the invention to provide apparatus which is of the kind described first hereinbefore and which permits a fast and complete filling of insulating glass panels with a gas other than air. 
     In accordance with the invention the apparatus is characterized in that sealing elements are associated with the top horizontal edge and the two substantially vertical edges of said plates, said sealing elements are extensible to a sealing position, a horizontally elongated tublike container for holding a gas other than air is disposed under the plates and has at its top an opening defined by edges which are connected and sealed to the plates, and a device for lifting the bottom of the tublike container is associated with said bottom. 
     In the apparatus according to the invention, the large gas exchange opening which is available in uncompacted insulating glass, e.g., in insulating glass which is still open at its bottom edge, is utilized in an advantageous manner. 
    
    
     Further features and details of the invention will become apparent from the following description of an illustrative embodiment of the apparatus according to the invention shown on the accompanying drawing in a diagrammatic side elevation. 
    
    
     The apparatus comprises two parallel plates 1 and 2, which are substantially vertical and are preferably slightly inclined from the vertical, e.g., by 5 degrees. As is shown on the drawing, these plates 1 and 2 may be constituted by the platens of a surface-pressing press for compacting insulating glass. In the embodiment shown by way of example, the plate 2 is stationary and secured to carriers and the plate 1 is displaceable in the direction of the double arrow 7 by way of fluid-operable cylinders 5 and rack-and-pinion drives 6. 
     Driven conveyor rollers 9 are provided on the underside of the stationary plate 2 below the space 8 between the plates 1 and 2 and are rotatable on substantially horizontal axes. Insulating glass panels 10 are conveyed on these conveyor rollers 9 along the stationary plate 2 into the space 8. 
     Sealing elements 11 are provided adjacent to the substantially vertical edges of the plate 2 and in position of rest are arranged in recesses in the plate 2. The sealing elements 11 consist of a flexible tubular member having longitudinal folds and through ducts 12 may be supplied with pressure fluid to extend the sealing elements to their sealing position, in which they engage opposite edges of the plate 1, and may be evacuated so that they are retracted to their position of rest shown on the drawing. Alternatively, sealing elements corresponding to the sealing elements 11 may be arranged also in the movable plate 1 and the two opposite sealing elements may be inflated until they engage each other and seal the space 8. 
     The space 8 is closed at the top by two webs 13, which are tightly joined to plates 1 and 2, respectively, and have folds 14 and are also tightly joined to a bar 15 provided between the webs 13. At least one conduit 15&#39; is provided, which extends, e.g., from the bar 15 and through which air can be sucked from the space 8 so that a slight vacuum is established in the space 8 in order to prevent a mixing of air with the heavy gas. An electronic speed control system is associated with the suction fan and ensures that the vacuum will remain constant even as the plate 1 approaches the plate 2. 
     The space 8 contains a measuring device 17, which is movable up and down along the double-headed arrow 16 and comprises a sensor, symbolized by the arrow 18, for detecting the top edge of the insulating glass panel 10, and a sensor 19, e.g., an instrument for measuring the oxygen content, so that the heavy gas-air interface can be detected. 
     A horizontally elongated container 20 is provided below the plates 1 and 2 and has bellowslike side walls 21, which are connected and sealed to the lower ends of plates 1 and 2. The bottom member 22 of the container consists in the illustrative embodiment of a rigid plate and can be lifted and lowered by a device 24 in the directions indicated by the arrow 23. In the embodiment shown by way of example, the device 24 is a mechanical device 25, 26, by which the bottom member 22 of the container 20 can be lifted and lowered in an exactly controlled manner. The heavy gas is quickly sucked back into the container 20 as the bottom 22 is lowered. 
     To fill an insulating glass which has not yet been compacted and which, as shown by way of example on the drawing, is still open along a lower edge resting on the conveyor rollers 9, the apparatus according to the invention is operated as follows. 
     The uncompacted insulating glass 10 is conveyed on the conveyor rollers 9 into the space 8 between the two plates 1 and 2. The end position of the insulating glass may be defined by a limit stop, not shown. As soon as the insulating glass has reached its end position, the plate 1 is approached to the plate 2 so that the space 8 is minimized, and the sealing elements 11 are extended until they engage the plate 1 on the surface facing the plate 2 so that the space 8 is sealed. Then the measuring device 17 is raised to a position in which its sensor 18 is disposed on the level of the top edge of the insulating glass 10. The lifting device 24 is then operated to lift the bottom member 22 of the container 20, which is filled with heavy gas, and air is sucked through conduit 15&#39; from the space 8 at the same time. As a result, the interface between the air (at the top) and the heavy gas (underneath) rises gradually until it reaches the sensor 19 of the measuring device 17. As soon as the interface has reached the sensor 19, which senses, e.g., the gas density or the oxygen content, the plate 1 is further advanced toward the plate 2 and the insulating glass 10 that has now been filled with heavy gas is compacted. 
     When the compacting operation has been terminated, the bottom member 22 of the container 20 is lowered and air is admitted from above into the space 8. When this operation has been terminated, the sealing elements 11 are retracted to their position of rest and the insulating glass which has been filled with heavy gas and compacted may then be removed from the apparatus by means of the conveyor rollers 9. 
     Another sensor 30, which is stationary, is provided adjacent to the top opening of the container 20 and serves also to measure the oxygen content of the surrounding gas. That sensor 30 is used to control the lowering of the bottom member 22 of the container 20 and to initiate the making up of the supply of heavy gas in the container when the quantity of heavy gas in the container has decreased below a predetermined value. 
     By means of the apparatus according to the invention insulating glass panels consisting of two or more panes can be filled with heavy gas, with a maximum air content of 5%, in small cycle times. As contrasted therewith, it was not possible to achieve air contents below 30% within reasonable cycle times where the conventional narrow tubes were employed. 
     The use of the apparatus according to the invention is not restricted to the filling of insulating glass with gases that are heavier than air but includes the filling of insulating glasses with any gas or gas mixture.