Plant for separating bulk of glass from an insulating glass unit

Abstract: A method for environmental handling of a sealed insulating glass unit comprising two or more layers of glass glued and jointed with an undesirable material, like environmental or health damaging, e.g. PCB containing, material, where the bulk of the glass is separated from the undesirable material so that the glass may be sent for reuse or recirculation and the unwanted material may be sent for disposal, recovery or destruction, wherein the bulk of the glass is separated from a strip comprising glass and the unwanted material by cutting the glass principally perpendicular to the glass surface by means of high pressure jet water flow at a distance from the edge of the glass, is described. A plant for carrying out the method and the use of high-pressure jet water flow for environmental handling of sealed insulating glass units is also described.

Description: The present invention relates to a plant for environmental handling of sealed insulating glass units. Sealed insulating glass units comprises two or more layers of glass which are held at a distance from each other by a spacer, usually an aluminium list, placed alongside the edges of the glass unit. The spacer is glued to the glass and the joint between the glasses is sealed with glue or joint filler. From about 1965 until about 1975 PCB was used as plastiziser in glue and joint fillers used in production of sealed insulating glass units in Norway and in other countries. Additionally sealed insulating glass units containing PCB was imported most probably until 1980. It is estimated that about 360 tons of PCB was imported to Norway for this purpose. PCB (polychlorinated biphenyl) is a synthetic chlorinated organic compound having inter alia the following characteristics: good insulating properties good chemical and thermal stability low corrosivity good lubricating properties low vapour pressure low inflammability Due to these properties PCB was used in a number of appliances in industry like power condensators, building products, electronics, refrigerating systems (e.g. refrigerators), lighting fixtures, etc. PCB is degraded very slowly and has harmful effects in the nature. PCB is fat-soluble and is concentrated in the food chain. PCB leads to health changes in humans and in animals. It weakens the immune system, increases the number of abortions and stillbirths, and lowers the stock of several animal species etc. PCB was abandoned by a regulation from the Norwegian Ministry of the Environment of November 16, 1979 and the ban came into force in 1980 and from this time on PCB-containing waste was to be delivered to special category waste plants. Today there is no way to handle PCB-containing sealed insulating glass unit effectively and environmentally correct. It is estimated that there is about 200 tons pure PCB in sealed insulating glass units in Norway. The goal is that this is handled in an environmental correct way and avoids that it is dumped at dumpsites. It is estimated mean times before replacement for sealed insulating glass units are about 25 to 30 years. As the peak of production was in 1974 - 1975, the maximum quantities of PCB containing sealed insulating glass unit are bound to be end in land fillings now. The amount might be as high as 40 tons pure PCB in the peak year for replacement. For the time being, sealed insulating glass unit has to be collected and stored until good methods and installations for handling of PCB containing sealed insulating glass units plus production lines for carrying out the process, has been developed and established. It is urgent to find good solutions for environmental correct handling of sealed insulating glass units. The PCB containing material is concentrated in a narrow stripe along the edge of the sealed insulating glass unit together with the aluminium list. Used glass is a valuable resource. Even if the use of the environmental hazardous PCB containing glue for the production of sealed insulating glass units was abandoned from about 1980, the glue or joint filler so far has been the main obstacle against recycling flat glass at a cost effective price. It is therefore desirable to develop a method for cost-effective recycling of used flat glass by removing the unwanted material in the edge zone of the flat glass effectively and at a fair price. Due to the costs connected with collecting and handling, it is today not feasible to recycle the glass in sealed insulating glass units to reuse the glass. If PCB containing material has been used to glue or seal the sealed insulating glass units, it is necessary to separate the glass from this environmental hazardous material in a safe and effective way. One method used today to separate glass and PCB containing material, is to cut loose the aluminium list together with the glue from the glass with a sharp knife. This is a labour intensive process and all PCB containing material is not removed from the glass. To remove all PCB containing material, the outer rim of glass has to be cut away by means of a glass cutter, which results in an increase in the amount of waste and results in considerable manual work. This method will also cause PCB spills to air in form of particles and gas. GB 2 164 879 A describes a method for cutting glass so that the cut glass edges are of acceptable quality. In order to achieve this the known method uses an abrasive fluid jet. The object of the present invention is to obtain a plant for fractionating a sealed insulating glass unit into a fraction of environmental hazardous waste, like glue and spacer, and a fraction of clean glass, so that the different fractions may be deposited, destructed or recycled and where the plant does not lead to problems for the working environment or outdoor environment, waste disposal or the like. This object has been met by a plant for separating bulk of glass from an insulating glass unit comprising two or more layers of glass which are held at a distance from each other by a spacer spaced along the edges of the glass unit glued and jointed with an undesirable material, which plant comprises: a means for tilting and transferring the insulating glass unit to a low friction table, a low friction table, whereon the glass unit is freely movable by means of air cushion or rollers, and a high-pressure jet water flow cutting device to which the insulating glass unit may be brought in the cutting position, said cutting device being able to travel in a linear track above the glass. The phrase "high pressure jet water flow" as used in this description and claims, also includes the use of sand added to the water to increase the cutting power of the high pressure water jet. Preferably the cutting device is set to cut the glass principally perpendicular to the glass surface at a given distance from the edge of the sealed insulating glass unit. The sealed insulating glass unit is first liberated from frame and case. If the health and environmental hazardous material pollute this wooden material, it has to be deposited in an approved special land fill or be burned in an approved plant for burning of material of this kind. The liberation from frame and case is often done at the place from where the window glass is removed from and is therefor irrelevant to the present invention. The sealed insulating glass units mat have been liberated from frame and case are then brought to the plant of the invention. The sealed insulating glass units are preferably transported substantially vertically into the plant. Inside the plant, the glass unit is tilted form the vertical position to a horizontal position and transferred to a low friction working table where the glass unit is freely movable. The low friction at the working table is achieved by means of an air cushion or rollers. The sealed insulating glass unit is moved at the working table to get in the correct position relatively to nozzle of the high pressure jet water cutting device of known type, said cutting device being able to travel in a linear track above the glass. A plant of this kind may include more than one high-pressure water jet nozzle cutting along the other edges of the same sealed insulating glass unit to improve the capacity of the plant. The high-pressure jet water cutting device is adjusted to cut transverse the glass surface right on the inside of the spacer or aluminium list. It is important that the water jet is not cutting into the glue or joint filler, as this may cause that some PCB or other environmental or health damaging compounds included in the glue or joint filler is released into the air or water. After cutting along all the sides of the sealed insulating glass unit, the cut away stripe comprising glass, spacer and the unwanted material is removed. The high pressure jet water cutting device is giving an even and straight cut so that the bulk glass that is liberated from the unwanted material may be used for the production of new window panes. The cut away material is removed for a possible recovery of material, depositing or destruction according to the requirements of the law or regulations. Broken sealed insulating glass units may also be handled according to this method. However, if the glass unit is heavily deformed, even more glass must be removed together with the spacer, glue and joint filler. Handling of broken glass units normally requires more manual work than the handling of unbroken glass units. The water used for cutting may include glue and aluminium besides in addition to glass. To avoid environmental harmful effluents, it is necessary to recirculate the water used for cutting. The plant therefor has to include a purge system for the water. If the glue or joint filler includes health or environmental hazardous substances that might escape into the air, the plant has to be designed with a suction point and a filter preventing these substances to escape.

Claims: Plant for separating bulk of glass from an insulating glass unit comprising two or more layers of glass which are held at a distance from each other by a spacer spaced along the edges of the glass unit glued and jointed with an undesirable material, with plant comprises : a means for tilting and transferring the insulating glass unit to a low friction table a low friction table, whereon the glass unit is freely movable by means of air cushion or rollers and a high-pressure jet water flow cutting device to which the insulating glass unit may be brought in the cutting position said cutting device being able to travel in a linear track above the glass.

Inventors: HAUGEN HELGE, HAUGEN, HELGE
Applicants: HAUGEN HELGE, HAUGEN, HELGE
Application year: 2000
Main classification: C03B33
IPC codes: C03B33, B26F3