WO1989003925A1

WO1989003925A1 - Method and arrangement for gas-filling of sealed glazing units

Info

Publication number: WO1989003925A1
Application number: PCT/SE1988/000544
Authority: WO
Inventors: Jan Karlsson; Ingemar Fasth
Original assignee: Window Barrier Hb
Priority date: 1987-10-19
Filing date: 1988-10-18
Publication date: 1989-05-05
Also published as: SE8704056L; SE459350B; SE8704056D0

Abstract

Method for gas-filling of sealed glazing units with a number of panes (2, 3, 4), sealed hermetically with respect to each other, with intermediate spaces (5, 6). In this method at least one opening (9) is allocated to each space (5, 6) for introduction of gas in the liquid state, and at least one opening (10) for discharge of the air which is situated in the spaces after the panes have been joined together. The gas, which is in the gaseous state at the use temperature of the sealed glazing unit (1) and at atmospheric pressure, is converted to the liquid state by compression and/or cooling. In its liquid state the gas is introduced into the respective space (5, 6) through the first opening (9). Heat, which is required for volatilization of the liquid gas, is supplied. During the volatilization process the second opening is kept open for emission of the expelled air.

Description

Method and arrangement for gas-filling of sealed glazing units.

Technical field:

The present invention relates to a method for gas-filling of sealed glazing units and an arrangement for carrying out the method.

Sealed glazing units or, as they are also called, insulating glass panels are generally used in windows for reducing energy transfer. This is achieved by the sealed glazing unit being made up of several panes, at least two panes mounted at a distance from each other and with the intermediate space filled with a gas. The space is thus hermetically sealed, and it is assumed that the gas, which is originally filled into the intermediate spaces, will be retained during the whole lifetime of the sealed glazing unit.

During assembly of the panes, the ambient air is enclosed between these, and many sealed glazing units are also supplied in this condition. However, better insulating values can be achieved with certain gases than with air. Certain types of panes, which have been covered with a transparent radiation-reflecting metal layer, additionally require filling with an inert gas, expediently a rare gas, in order to prevent the metal layer from being oxidized or undergoing any other change. The invention relates to the filling of sealed glazing units with a gas which replaces the enclosed air.

Prior art:

Since the production of a sealed glazing unit would be extremely complicated and require an extensive apparatus if it was to be attempted, during assembly itself, to enclose any gas other than the ambient air, it has been necessary to replace the enclosed air with the desired gas after the sealed glazing unit has been assembled.

It has been found that such a filling process, with the enclosed air being replaced by a gas, is considerably difficult to carry out in a satisfactory manner. In order to achieve a satisfactory replacement of the air by the filled-in gas, it is required that the two components are not mixed with each other to any great extent during the filling process. Filling the gas at a certain overpressure gives rise to considerable gas movements in the narrow but, at the same time, extensive space between the panes, and this results in an intense mixing of the injected gas and the original air.

In order to avoid this resulting in the sealed glazing unit leaving the filling operation with a mixture of the gas in question and air, which would lead to inadequate insulating levels or, in the case of panes coated with a reflecting layer, to a risk of the latter being oxidized, the filling gas is injected in a considerably greater amount that is needed to fill the space. Thus, during filling, a mixture with the air is initially created and, thereafter, the gas is used to force this mixture out.

Technical problem:

This is an unsatisfactory method, since there is a Large consumption of gas together with consequently high costs, and there is no guarantee that considerable residual amounts of air will not remain. Moreover, a mixture of the filling gas and air is obtained as waste, which can result in environmental risks if it is discharged into the atmosphere or, a ternatively, gives rise to further costs if it is to be regenerated or dealt with in some other way. This aspect is of particular importance when use is made of filling gases with environmentally hazardous components. Thus, compound gases with a great radiation-absorbing action and containing, inter alia, freons have acquired wide-spread use. Release of freons into the atmosphere is considered undesirable, and an implementation of the filling operation, resulting in an overcharging and discharge of the gas, is therefore particularly unsuitable in gases of this type.

Solution:

In the method according to the invention a medium, which is in the gaseous state at the use temperature of the sealed glazing unit and at atmospheric pressure, is converted to the liquid state by compression and/or cooling, and, while it is at least partially in its liquid state, it is introduced into the respective space through a first opening, while such a supply of heat is provided as is required for volatilizing the liquid medium, and during the volatilization process a second opening is kept open for emission of the air expelled during the volatilization process. In its gaseous state the medium constitutes the gas-filling of the glazing unit.

Advantages :

The present invention provides a method for gas-filling of sealed glazing units, which method results in a high degree of replacement of the enclosed air by the filling gas, with a very small degree of over-charging.

The invention also provides an arrangement for carrying out such a gas-filling process.

Description of the figures:

Three embodiments of the filling arrangement according to the invention are described below, these embodiments being illustrated in the attached drawings. Fig. 1 shows a cutaway view of a sealed glazing unit with three panes and with a filling arrangement according to the invention, in its first and second embodiments, illustrated in the connected state, the cutaway extending along the line I-I in Fig. 2, which figure shows a partial view of the sealed glazing unit in Fig. 1, with part of the filling arrangement also shown; and Fig. 3 shows the filling arrangement in a third embodiment.

Preferred embodiments:

In the figures a sealed glazing unit, of the type to which the invention applies, is designated by reference 1 « According to Fig. 1 it comprises three panes 2, 3 and 4. Two spaces 5 and 6 are formed between the panes. The width of the spaces is determined by two frames 7 of tubular profiles, usually of aluminium. These profiles follow the edge of the panes 2-4 all round, so that the spaces 5 and 6 are completely closed. Fixing between the frames 7 and the panes is effected by means of layers 8 of an elastomer which has low gas permeability with respect to the gases which are to be filled into the intermediate spaces 5, 6. For the gas-filling of the intermediate spaces, a hole 9 is made in each of the frames 7 and, for removal of the enclosed air during filling, a hole 10 is arranged in each frame essentially at a position opposite the hole 9. A water-absorbing mass 11, for example silica gel, is expediently inserted in the hole area in the tubular profiles which form the frames 7, and the holes 9, 10 also extend through this mass.

Fig. 1 shows, by way of example, three panes and, thus, two intermediate spaces. However, there can also be two panes and a single intermediate space, or more than three intermediate spaces. The frames do not need to have exactly the appearance shown, another profile form being possible. However, the basic form, namely that several panes are hermetically sealed with respect to each other (the holes 9 and 10 will be closed in the use state) and thus form one or more spaces, is a prerequisite of the invention. As regards the number and position of the holes 9 and 10, this can vary for different pane sizes, but it is assumed here, for the sake of simplicity, that there are only two holes and that they are in positions opposite each other. Fig. 1 shows, partially in cutaway view, a gas-filling arrangement according to the invention. It is designated by reference 14 and consists of a number of main parts: a connection bracket 15, an electromagnet 16, a mass flow regulator 17, a processor 18, a control unit 19 and a heating arrangement 20, which is shown in Fig. 2. The mass flow regulator 17 is designed for attachment of a connecting hose 21 to a gas bottle 22.

The bracket 15 comprises a connection nipple 25 with a gasket 26. The nipple 25 is attached to a valve housing 27 in which a filling nozzle 28 is secured. The latter empties into a bore 29 in the valve housing 27, which is finished with a seat 30 for a valve needle 31, which runs in a guide 32. From the guide 32 there extends an angular bore 33 which forms the connection between the bracket 15 and the mass flow regulator 17.

The valve needle 31 is actuated in the direction towards the seat 30 by a spring (not shown) and is attached to the armature of the electromagnet 16. The armature can be moved in the customary manner by placing the magnet coil under tension. In this connection the valve needle 31 is drawn outwards against the spring force and opens the passage from the bore 33 to the bore 29 by means of the valve needle 31 lifting from the seat 30. This means that gas can flow from the mass flow regulator 17 and out through the end of the nozzle 28 provided with a hole. Only the housing of the electromagnet 16 is shown, since the construction of such an arrangement is already well known.

The mass flow regulator 17 is designed in such a way that, when it is placed under gas pressure from the connecting line 21, it allows a carefully regulated mass flow to pass through to the bore 33 per unit of time. Only the outside of the regulator is shown. Regulators of this type are, however, already well known and can be of many different designs. In a customary embodiment a regulator of this type is designed as a control valve whose opening area is controlled by the pressure on the intake side of the valve, such that an increasing pressure gives a smaller opening area, and vice versa. This can be achieved, for example, by a valve body, springloaded in the opening direction, being actuated in the closing direction by a diaphragm or a plunger, in turn actuated by the pressure in front of the valve. If the pressure in front of the valve increases, the spring force is then counteracted by a higher pressure against the diaphragm or the plunger, and the valve body moves towards the closure position. In this way variations in the pressure are compensated by changes in the opening area. By means of correct adjustment of the valve parts, it is thereby possible to obtain a constant mass flow. However, there are also other principles available for producing a valve which gives a constant mass flow per unit of time independent of factors which can vary in practical operation, such as pressure and temperature.

The heating arrangement 20, as shown in Fig. 2, is designed for heating the frame 7 of the sealed glazing unit 1. It can be designed, as shown in Fig. 2, as a yoke 35 which is secured by the bracket 15 and is provided, at its ends, with electrical heating elements 36.

The filling arrangment 14 now described, or parts thereof, can be contained in an insulating shell in order to limit the effects of the ambient temperature and to avoid heating of the gas which is to flow through the arrangement. The heating arrangement 20 can be insulated separately or lie outside the insulating shell.

The processor 18 is designed to provide current supply via lines 38 to the electromagnet 16 for lifting the valve needle 31 from the seat 30. It is further designed to provide current supply via lines 39 to the heating arrangement 22. The control unit 19 is connected via lines 40 to the processor. The control unit is provided with a keyboard 41, which is shown diagrammatically. The processor is designed so as to provide, by means of receiving control impulses from the control arrangement 19, precise control impulses to the electromagnet 16 and the heating arrangement 20 by adapted ratings for these units. The control cycle, which will thereby be obtained, emerges from the following function description.

The second embodiment can also be said to be shown by Fig. 1. In this respect the nipple 44 shown at the discharge hole 10 is intended to be an oxygen meter. The latter is connected to the processor 19 for controlling the electromagnet 16 so that, when the oxygen content in the discharge air has been eliminated or reduced to a bottom limit value by the original air in the space 5 having been replaced by gas and the latter then beginning to flow out through the discharge hole 10, the valve for gas intake is closed. Thus, by this means, over-charging together with unnecessary discharge of gas is effectively avoided. Meters which can register the oxygen content in a gaseous mass are known and can be used in this context.

If this system alone is relied on, the processor 19 does not have to be designed for adjustable time measurement, as was described in connection with the first embodiment. However, the second embodiment does not preclude the use of the two systems described, that is to say a time meas u r e m e n t adapted to the volume of the space 5 and an oxygen metering. In this way, greater safety is obtained against over-charging, as would occur, for example, if the oxygen meter were to become inoperable. Moreover, it is possible to create a standby situation by virtue of the fact that the processor determines the moment shortly before the flow of oxygen througn the discharge hole stops, by means of the fact that the space is filled. Alternatively, instead of a sensor reacting to oxygen, it is possible to use a sensor reacting to nitrogen or a sensor which reacts to any component in the filled gas, so that the gas flow is shut down when this component begins to flow out through the discharge hole.

The third embodiment is shown in Fig. 3. The sealed glazing unit is shown partially and has the same designations as before. The gas-filling arrangement, here designated 45, has a housing 46 with a cylinder bore 47 and a long probe 48, which is intended to be introduced through the hole 9 and into the space 5. The probe is tubular and is connected to the cylinder space 47 and has, at its part situated inside the space 5, a large number of slots 51 or other openings. In the cylinder bore there is an inlet hole 49 which is in connection with a conduit 50 which leads to a source of liquid gas. In the cylinder bore there is a plunger 52 which can be pressed into the cylinder bore by means of a rod 53 which runs through a cylinder head 54.

The aim is that the space in the cylinder bore 47 will be filled from the channel 49 with liquid gas by injection from the line 50 while the plunger 52 is withdrawn a certain distance. The length of this distance is proportional to the volume which can be accommodated in the cylinder space. The plunger can, by being inserted, convey this volume through the probe 48 and through its holes 51 out into the space 5. By arranging for a number of fixed positions for the withdrawal of the plunger, it is possible to obtain injection volumes which correspond to the gas required for filling the respective spaces 5 after the liquid gas has assumed the gaseous state. In other words, it is possible to adapt the injection mechanism to different window sizes.

In addition to what is shown in Fig. 3, there are arrangements for obtaining the said fixed positions for the withdrawal of the plunger, such as control arrangements for the movements of the plunger, these being either manual or machine-operated. Moreover, valves may be required in the inlet channel 49 and in the brobe 48 for obtaining the described flow of the gas in the liquid state. However, such arrangements are well known, for example from injection engine technology, and do not need to be described further.

The filling with gas takes place expediently when the sealed glazing unit 1 has reached the stage of preparation when its panes 2 and 4 have been joined together around the frames 7 by means of the sealing elastomer 8. The holes 9 and 10 will be open at this time. The filling can now begin and, in order to save time, this can be carried out while the sealed glazing unit is held pressed together in a press arrangement, while the elastomer is hardening. When filling is to begin, the arrangement 14 according to the first embodiment should be connected to the glass bottle 22, and the latter should contain a sufficient amount of gas for the operation. This gas should be stored in the gas bottle in liquid form. For certain gases this can be obtained, depending on the critical temperature of the gas used, at the working temperature (room temperature), while other gases must be maintained cold. In the latter case in particular the arrangement must be provided with insulation.

The aim is that the gas will be continuously injected in liquid form into the respective intermediate spaces 5, 6 and will be allowed to gasify there. For this purpose heating is required. In order to be able to time-control the process of gasification and in order to prevent excessive cooling from the frame and the panes (the glass may crack at excessive temperature differences) it can be expedient to arrange for heating, which can be effected by means of the arrangement 20. Such heating may thus be desirable even when the liquid gas is not cooled.

When the filling operation is to begin, the nozzle 28 is introduced through the hole 9, so that its open end is situated inside the space 5. The hole 10 should be open at the same time. Using the keyboard 41 a filling amount is chosen such that the amount of liquid gas injected is able, during its gasification, to completely fill the space, with expulsion of the existing air through the hole 10. This involves the valve needle 31 being lifted from the seat 30 for a certain time, the length of which is determined, on the one hand, by the amount required for filling the space, that is to say depending on the volume of the space, and, on the other hand, by the amount which the mass flow regulator 17 allows to pass per unit of time. So that this control can be carried out in actual operation, the processor 18 is designed to determine the time during which the electromagnet 16 is to be placed under tension, and the valve is thus to be open, on the basis of input values for the size of the window, which values are input via the keyboard 41 using clear designations, such as height and width, or determined type designations. These values are then converted in the processor 18 to open times for the valve. These open times are expediently produced by calibration on the basis of certain basic calculations. The calibration is expediently effected by measuring, by means of a gas analysis device, the discharge through the hole 10 with respect to air and gas content. It may also be necessary, during calibration, to take into consideration external circumstances such as the ambient temperature and air pressure. During use the values for such factors can then be input to the processor 18 for correcting the open times of the valve.

By means of such a precise pre-setting of the processor, it is possible to obtain such good precision in terms of filling that either under-charging or over-charging takes place. However, it is possible to carry out gas analysis (cf. the second embodiment) so as to check that the setting is correct. At all events, it is desirable for the equipment to be re-calibrated one time after another. Of course, if the arrangement is to be used for different gases, a control scheme must be established for each gas. In the first embodiment it is assumed that the gas will only flow out through the hole 10. There is thus no need for a nipple, such as the nipple 44 shown. However, it may be expedient to control the discharge of air, for example by extracting the air at a certain rate or, inversely, restricting its outflow. This can be effected by means of arrangements in the nipple 44.

In the second embodiment the reference 44, as has already been described, indicates a gas sensor or connection to such a sensor. As has emerged, this sensor will record a component either in the outflowing air or in the gas which is to replace the air in the space 5. Thus, by this means the time at which the space is filled and all the air has flowed out can be determined in order to close down the inflow.

A basic idea behind the invention is, accordingly, that the gas will be introduced into the space in an at least partially liquid state and under such conditions that gasification will take place inside the space. This means, therefore, that the temperature and the pressure will be such that at least part of the liquid gas from the liquid phase will convert into the gaseous state inside the space which is to be filled. In actual operation this means that gasification is to take place approximately at room temperature and atmospheric pressure. It has been stated above that the gas is to be introduced into the space in at least partially liquid form, which means that the invention does not exclude the possibility that some of the gas stored in the liquid state already undergoes gasification in the filling apparatus before it has entered the space 5. However, this gasification should not be so great that a situation arises in which only gas is injected, with accompanying disadvantages in the shape of turbulence and other disturbances. On the other hand, a light flow of an aerosol, that is to say liquid dropLets suspended in the gaseous phase, gives the desired result, with a gradually evaporating gas mass which rises and forms a shield, which forces the enclosed air out.

In this context it should also be mentioned that the mass flow regulator 17 can, in the case of a mixture of liquid phase and gaseous phase, have different designs. Thus, within the known technology there are mass flow regulators which operate only with liquid, that is to say a non-compressible medium, and others which operate with gases or aerosols. The type used should of course be one which is adapted to the prevailing conditions in question.

In the third embodiment according to Fig. 3 there is purely liquid injection. Liquid gas is introduced in this case into the space in the cylinder bore 47 while the plunger 52 is withdrawn. The gas is introduced through the channel 49 via the line 50 from a storage container. When the cylinder is filled, in which connection the position of the plunger determines the volume of liquid gas, the plunger 52 is introduced into the cylinder bore and the liquid gas flows through the probe 49 and out through its openings 51 in fine streams. Under suitable temperature conditions a slow gasification is obtained when the liquid emerges into the space 5 in the manner intended by the invention.

When the pane is in use, the prevailing conditions in the surroundings are atmospheric pressure and temperatures between about -30°C and +50°C. After final sealing, any pressure in the panes which differs appreciably from the atmospheric pressure cannot be permitted, since, in the case of normal window sizes, the panes cannot tolerate any appreciable pressure differences.

In order for the desired complete filling to be achieved without over-charging, the liquid gas, when it has entered the space, should be gasified while it rises in the space and pushes the air ahead of it and out through the hole 10 without any essential whirling and mixing. The gases which are used for filling windows are almost always heavier than air and therefore spread out below the air and, as gasification progresses, force the latter out. It is important that the Liquid gas should flow in smoothly. It is advantageous if the frame part, in which the injection hole is situated, is kept in a horizontal position so that the liquid gas can flow out to form an even shield over which the gasification can take place relatively uniformly, so that the air is also lifted uniformly and the formation of turbulence is avoided. In the case of large windows this can be further improved on if injection takes place at several positions simultaneously and emptying of the air can also take place at several points.

In the above text the expression "the liquid gas" has been used. This is not entirely accurate, but nevertheless clearly indicates the conditions, since the medium used under the use conditions - approximately atmospheric pressure and room temperature - is gaseous. The correct expressions are, however, that the medium in question is in its liquid phase in the first state and, in the second state, the use state, in its gaseous phase. The expression "medium" is thus used in the subsequent patent claims.

After the filling cycle has been completed, the holes 9 and 10 should be sealed. This is best achieved using the same type of elastomer as is used for holding the panes and the frames together. The elastomer is injected as a mass which is able to harden. This has been carried out in the left space 6 in Fig. 1, where plugs 45 of sealing material are shown. The filling is continued in the manner described until all the spaces are filled. For increasing rationalization, several arrangements 14 can be set up for simultaneous filling of all the spaces in windows with more than one space. For as smooth as possible a filling process, measures should be taken to prevent vibrations and other movements in the window.

Claims

C LA I M S

1. Method for gas-filling of those sealed glazing units which comprise a number of panes (2, 3, 4), sealed hermetically with respect to each other in the use condition, between which there are arranged spaces (5, 6), the method involving the arrangement of at least one opening (9) for each space (5, 6) for inflow of the medium which, in the gaseous state in the use condition, will be situated in the said spaces, and at least one opening (10) for discharge of the air the which is situated in the spaces after the panes have been joined together, in which connection the medium is introduced through the first opening while the air is released through the second opening, characterized in that the medium which, as has been stated, is in the gaseous state at the use temperature of the sealed glazing unit (1) and at atmospheric pressure, is converted to the liquid state by compression and/or cooling, and in that the medium, while at least partially in its liquid state, is introduced into the respective space (5, 6) through the said first opening (9) while the said second opening (10) is kept open, in that such a supply of heat is provided as is required for volatilizing the liquid medium, and in that, during the volatilization process, the second opening (10) is kept open for emission of the air expelled during the volatilization process.

2. Method according to Claim 1, characterized in that the liquid medium is introduced through the opening (9) in a frame part (7) of the sealed glazing unit while this part is kept in an essentially horizontal position and while, at the same time, the second opening (9) is directed upwards and is positioned in a frame part which is at Least essentially opposite the first-mentioned frame part.

3. Method according to Claim 1, characterized in that the first frame part (7) is subjected to forced heating during the volatilization process.

4. Arrangement for carrying out the method according to Claims 1, 2 and 3 for gas-filling of those sealed glazing units which comprise a number of panes (2, 3, 4), sealed hermetically with respect to each other and to the frame element (7) in the use condition, between which there are arranged spaces (5, 6) to each of which there is allocated at least one opening (9) for inflow of the medium which, in the gaseous state in the use condition, will be situated in the said spaces, and at least one opening (10) for discharge of the air which is situated in the spaces after the panes have been joined together, characterized in that the arrangement comprises a vessel (22) for accommodating the medium in the liquid state, a regulator (17) designed for exact metering of the medium, a valve bracket (15) designed for temporary passage of the medium from the regulator and provided with a control device (16) for controlling the valve (30, 31) of the bracket and a nozzle (28) for introduction of liquid medium into the said spaces (5, 6) through the said opening (9) and, for regulating the control device (16), a processor (18) which is designed to introduce a defined amount of the medium, which is designed, after volatilization, to fill the space into which it is introduced, so that, during the volatilization process, the air enclosed in the space is expelled through the second opening (10).

5. Arrangement according to Claim 4, characterized in that the processor is designed, after receiving from a control unit (41) data with respect to the sealed glazing unit (1) in question which is to be filled, so as to control the control device (16) to introduce an amount of medium adapted to the filling of the respective spaces (5, 6) of the sealed glazing unit.

6. Arrangement according to Claim 5, characterized in that the regulator (17) is a mass flow regulator which is designed to allow through flow of the medium with a determined amount per time unit, that the valve (30, 31) is designed, when in the open position, to allow the amount of medium supplied from the mass flow regulator to pass through, and in that the processor (18) is designed to maintain the valve open, by means of the control device (16), for a determined period of time which, by means of the arrangement of the processor and the control unit (41), is adapted to introduce an amount of medium into the respective space such that its gasification leads to filling of the space.

7. Arrangement according to Claim 4, characterized in that the processor (18) is connected to a gas sensor (44) at the discharge opening (10), which is designed to detect the change-over from discharge of the air originally present in the space and the filled- in medium, and in that the processor is designed to shut down the supply of medium to the space by controlling the valve (30, 31) of the bracket, when the sensor has recorded that at least the majority of the air flow has ceased.

8. Arrangement according to Claim 4, characterized in that the regulator (17) for metering the medium is essentially made up of an injection arrangement for forcing the liquid medium out into the space (5).

9. Sealed glazing unit, characterized in that it is filled with a medium which has been filled into the glazing unit by means of the method stated in any one of Claims 1-3.