Apparatus and method for cooling glass with air jet

Abstract

An apparatus and method for temporarily reducing the blow width of a glass convective cooler according to the width of the glass to be cooled. In a convective cooler, the glass is cooled by an air jet. The main purpose of reducing the blowing width is to reduce the energy consumption of the convection cooler. In the apparatus, the position of a closing plate connected to the same shaft is changed by rotating the shaft passing through the continuous blowboxes, thereby closing the blowing width of several blowboxes that are continuous in the width direction of the glass. When the to-be-cooled glass sheet is suitable for the narrowed blowing width, the blowing length can be shortened. Convection coolers including within the scope of the invention are primarily used for tempering glass sheets.

Description

Technical Field

[0001] The present invention relates to an apparatus and method for cooling glass with air jets, and more particularly to tempering glass with air jets. Background Art

[0002] The device of the present invention is a glass sheet convection cooler, which consists of a glass sheet conveying track, an air generating unit, an air supply duct, and a plurality of rectangular blowing boxes above and below the glass sheet to be cooled, wherein the blowing boxes are continuous in the moving direction of the glass and transverse to the moving direction of the glass. The air jet for cooling the glass sheet is discharged from the blowing holes in the blowing box toward the glass sheet to be cooled. The glass sheet conveying track is usually a roller track. The air generating unit is usually a blower, and the overpressure (i.e., the blowing pressure) generated in the blower box is usually 500-40000 Pa. The blowing pressure can be adjusted by changing the rotation speed of the blower impeller with a frequency converter.

[0003] Such glass sheet convection coolers are well known and are used in particular in glass sheet tempering lines. Among them, convection coolers are often referred to as glass tempering coolers. The motor power of the tempering cooling blower is usually 100-400 kilowatts, and there are usually two blowers.

[0004] The general disadvantages of glass tempering convection coolers are the power consumption of the air generating unit and the high motor power, which increases with the thickness of the glass to be tempered. The power consumption increases the production costs and increases the CO2 emissions. The larger blower and motor increase the manufacturing costs.

[0005] Typically, the width of the glass sheet or glass sheet load to be tempered is substantially smaller than the blast width of the convection cooler. In this case, a portion of the convection cooling is unnecessary because a portion of the air jet is not directed onto the glass sheet. In a convection cooler of the type described above consisting of a continuous rectangular blast box, power consumption can be reduced by eliminating the unnecessary blast described above.

[0006] In the past, attempts have been made to overcome this drawback in a number of different ways.

[0007] In the publication US4874418A, the blowing port along the width of the glass tempering cooler is closed by pushing the baffle inward as the glass loading width narrows. One disadvantage is that the baffle is easily blocked because a minimum gap is required to prevent leakage that compromises the sealing of the closure. Another disadvantage of this technology is the need to move a baffle equal to the length of the narrowing loading width, that is, it requires significantly more space on the side of the glass tempering cooler. The advantage is that with this technology, stepless adjustment of the blowing width can be achieved.

[0008] In prior art publication US3522029A, as the glass loading width narrows, the opening along the width of the glass tempering cooler is closed by moving a baffle equipped with an opening approximately at least by the diameter of the nozzle opening. The advantage of this technique is that it does not require much additional space on the side of the glass tempering cooler relative to the solution of publication US4874418A, because the required movement of the baffle is very short. The disadvantage associated with the solution of publication US4874418A is that this technique can only narrow the blowing width by one step.

[0009] In publication EP3042881A1, this problem is solved by an air distribution part having a width of the entire length of the blow box, wherein the blow box is divided into individual compartments by partition walls, and the blow air can be prevented from entering the edge compartments by closing the openings in the air distribution part. The disadvantage of this solution can be said to be the space required for the air distribution part and its connecting ducts above and especially below the glass sheet. This solution significantly increases the price of the temperature controlled cooler.

[0010] In the prior art disclosure document CN111620556A, unnecessary blowing is eliminated by closing the blowing box with a partition-shaped gate knife valve. This technology is able to remove unnecessary blowing width in several steps. The disadvantage is that the gate knife valve and its actuator require space above the blowing box, especially below. On the lower side, the functional reliability of the baffle of the gate knife is reduced because broken glass pieces usually gather in the tempered cooler, where the gate knife actuator is located. In addition, outside the blowing box, the baffle is in an open position, with the risk of hitting glass fragments and getting dirty. This can easily lead to baffle clogging problems. The adhesion and accumulation of glass dust in the moving parts of the equipment will reduce its durability. Another disadvantage is that since the baffle of the gate knife valve moves into the blowing box, air will constantly leak from the opening to the outside of the blowing box. Leakage will significantly reduce the energy saving effect to be achieved.

[0011] With reference to the above-mentioned existing solutions, the problem is to solve the unnecessary blow-off with an apparatus and method that is technically reliable, cost-effective, adaptable to existing structures and removes the unnecessary blow-off as effectively as possible. Summary of the invention

[0012] The object of the present invention is to provide a glass sheet convection cooler with which the majority of the air jet cooling not directed towards the glass load can be effectively removed in the width direction of the glass and the glass load by a reliable, cost-effective and compact mechanical solution and placed in structures of existing type.

[0013] The object of the present invention is achieved by a device for reducing the blowing width of a glass convection cooler, wherein the convection cooler comprises blowing boxes on both sides of the glass, the blowing boxes are continuous in the direction of movement of the glass, and air is discharged from the blowing ports of the blowing boxes toward the glass to be cooled. The device comprises several closing plates located in the continuous blowing boxes and connected to the same shaft, the shaft being arranged to pass through the continuous blowing boxes supporting the shaft, and an actuator, by means of which the shaft can be rotated to prevent the air from flowing into the ends of the blowing boxes through the closing plates.

[0014] The object of the present invention is also achieved by a method for temporarily reducing the blowing width of a glass convection cooler based on the width of the glass to be cooled. The convection cooler is composed of blowing boxes located on both sides of the glass, which are continuous in the moving direction of the glass, and air is discharged from the blowing holes of the blowing boxes toward the glass to be cooled. In this method, the position of the closing plate attached to the same axis is changed by rotating the axis passing through the continuous blowing boxes, thereby shortening the blowing length of several continuous blowing boxes.

[0015] These objects are achieved on the basis of the features set out in the independent claim. Preferred embodiments of the invention are set out in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the following, the present invention is described in more detail with reference to the accompanying drawings, in which:

[0017] Figure 1 A cross section of a glass convection cooler viewed from the side is shown.

[0018] Figure 2 A cross section of a blow box according to an embodiment of the present invention, viewed from the direction of glass movement, is shown.

[0019] Figure 3 A continuous blow box of a glass convection cooler according to one embodiment of the present invention is shown.

[0020] Figure 4 Shows the Figure 3 Convection cooler.

[0021] Figure 5 A closing plate and its mechanism of a device according to an embodiment of the present invention are shown. DETAILED DESCRIPTION

[0022] Figure 1A convection cooler 1 for a glass sheet G is shown, into which the glass sheet is transferred from a heating furnace, which is typically a glass tempering furnace. From the glass tempering furnace, the glass sheet is transferred from the direction of arrow MD to the convection cooler, typically at a temperature of about 650° C. Preferably, the convection cooler is a glass tempering cooler. The glass sheet is moved in the convection cooler by being transported by a roller track formed by rollers 3. The movement of the glass sheet in the convection cooler can be continuous, i.e. in one direction, or the glass sheet can move back and forth on the roller track. Figure 1 In the figure, above and below the glass sheet G carried on the roller 3 are blow boxes 2. Air is fed into the blow boxes by a blower. The blow boxes 2 are equipped with blow holes 7, and the air generated by the blower is discharged toward the glass sheet G as a jet through the blow holes 7. There are a plurality of continuous blow boxes in the moving direction of the glass, which are rectangular and parallel to the roller. The impact of the air jet on the glass sheet generates a cooling force, cooling the glass. This is so-called forced convection cooling.

[0023] Figure 2 A blow box 2 is shown below the glass when viewed from the moving direction of the glass. The length of the blow box is usually slightly greater than the length W of the blow box equipped with the blowing holes 7, which is usually 1.2-3.4 meters. The air is fed into the blow box from the first end of the blow box (see air entry), i.e. from the starting end. Typically, the height of the blow box decreases in the direction of air flow in the blow box, i.e. increases with the distance from the first end to the other end (i.e. the end). This reduction in height makes the blowing pressure in the blowing holes along the length of the blow box uniform. The starting end of the blow box is at Figure 2 The middle is marked with the letter S, and the end is marked with the letter E. Figure 2 In the process, air is fed into the blowing box from the starting end S of the blowing box. Figure 2 The blow box is equipped with two closing plates 5a and 5b. In the figure, the closing plate 5b at the starting point WB of the length equipped with the blowing hole is in the open position, while the closing plate 5a at the distance WB is in the open position. WA is equipped with a blowing hole from the length and is in the closed position. Therefore, the closing plate 5a prevents air from flowing into the end of the blow box. Therefore, the closing plate 5a attempts to remove the blowing from the blowing hole between the length W and WA of the end of the blow box. Accordingly, when in the closed position, the closing plate 5b will attempt to remove the blowing from the blowing hole between the length W and WB of the end of the blow box. Usually, the end of the blow box is therefore the part of the blow box downstream of the closing plate in the air flow direction. The closing plate is connected to the shaft 4 passing through the side of the blow box. The shaft is straight, horizontal, and parallel to the movement of the glass. The side of the blow box is the side wall of the blow box, which is usually vertical. The blow box also includes a sealing member 6, and when the closing plate is closed, the edge of the closing plate is pressed against the sealing member 6. Preferably, the sealing portion covers the entire circumference of the blow box cross section.

[0024] Figure 3 and Figure 4 The blow boxes on one side of a glass sheet convection cooler are shown. The figures show a distribution duct 8 from which air is fed to several blow boxes 2. The air enters the distribution duct from the blower via a supply duct not shown in the figures. The blow boxes 2 include a cover part 10 with blow holes 7. In the view of the figures, the blow boxes 2 are mostly open, i.e. only a small part of the cover part 10 is in one blow box. Typically, the cover part is a continuous part over the entire length of the blow box 2, which is connected to the frame of the blow box with screws and sealant. For the sake of clarity and simplification of the drawings, Figure 1 , 2 and 5 do not specify the cover part in the nozzle box. Figure 3 In the blow box of FIG. 1 , two rows of closing plates 5a, 5b can be seen. The closing plate 5a is connected to a shaft 4 different from the closing plate 5b. The shaft 4 is arranged to pass through a plurality of blow boxes that are continuous in the direction of glass movement, and the shaft is also supported by these blow boxes. Figure 3 and Figure 4 Also shown is a belt 11 included in the closing plate actuator 12. The belt 11 is connected to a pulley mounted on the shaft so that the movement of the belt rotates the shaft. The belt can also be a chain or other type of transmission member between the shaft and the actuator. The closing plate is guided to the open / closed position by rotating the shaft, i.e. by turning it about a quarter of a turn relative to its longitudinal axis. Both shafts have their own belt and actuator. With the aid of the actuator 12, the shaft 4 can be rotated to prevent air from flowing into the ends of the blow box through the closing plates 5a, 5b. The actuator can be manually or mechanically operated. It can include an electric motor or a pneumatic machine. The actuator 12 is preferably arranged at the end of the blow box. This is particularly preferred below the glass because the actuator can be farther from the floor and at the same time farther from the broken glass fragments that gather there due to the reduced height of the above-mentioned blow box towards its end. This improves the reliability and durability of the actuator. Figure 3 The width GW of the glass sheet G, i.e. the dimension transverse to the glass entry direction MD, is smaller than the distance ( Figure 2 and 3 Therefore, when the glass sheet is placed on Figure 3 When on the roller track shown, the closing plate 5b can be closed by rotating the shaft 4 to prevent air from flowing into the end of the blow box so that the glass sheet does not extend to the closing plate 5b.

[0025] Figure 5 The closing plates 5a, 5b in the blow box 2 are shown in more detail. In the figure, the closing plates are in the closed position. Figure 5In the example, the closing plate is divided into two sub-areas A1 and A2 on both sides of the axis. The surface area of ​​sub-area A1 is larger than the surface area of ​​sub-area A2. The surface area of ​​the entire closing plate is the sum of areas A1 and A2. Figure 5 Also visible is the bearing 9, by which the shaft is supported by the blow box. Figure 5 The bearings in the bearing are plain bearings. The closing plate has a bushing, usually in the form of a shaft, the size of which is approximately the outer diameter of the closing plate, through which the shaft passes. The closing plate is fixedly connected to the shaft, for example by screws. Figure 5 In the view of FIG. 1 , the sealing member 6 will approximately surround the entire periphery of the blow box cross section, but for the sake of clarity of the figure, it is not shown beyond two partial lengths of the sealing member 6. It is important that the sealing portion extends from the blow box inner surface in the normal direction of the blow box inner surface further than the gap between the closing plate and the blow box inner surface. Possible leakage of the gap between the contact surfaces of the sealing member and the closing plate can be reduced by coating the sealing member side of the closing plate and / or the surface of the closing plate side of the sealing member with an elastic substance such as rubber. Figure 5 Blowing holes 7 are also shown.

[0026] exist Figure 3 and 4 In the embodiment of the present invention, the closing plates of 13 consecutive blow boxes are connected to the same axis. Therefore, by rotating one axis, the blowing length of 13 blow boxes can be closed at the same time. The present invention is characterized in that the closing plates of several consecutive blow boxes, preferably at least five blow boxes, are connected to the same axis. In a more preferred embodiment, the number is at least 10. As the above number increases, the device becomes simpler and more cost-effective. Usually, the convection cooler has 10-100 consecutive blow boxes on both sides of the glass, and the spacing between the blow boxes in the direction of glass movement is usually 70-140 mm. There is an air gap between the consecutive blow boxes, and the air that has contacted the glass surface is discharged from the air gap.

[0027] According to a preferred embodiment, the surface areas A1 and A2 of the sub-areas of the closing plate on either side of the axis are each at least 1 / 3 of the entire surface area A1 + A2 of the closing plate. In this case, the axis is suitably located in the middle of the closing plate.

[0028] In a preferred embodiment, the device is equipped with a sealing member 6 dedicated to the closing plate, against which the surface of the closing plate is pressed in the closed position, so that the closing plate portion on the first side of the shaft is pressed against the sealing member from its surface opposite to the closing plate portion on the other side of the shaft. The pressing of the closing plate against the sealing member reduces leakage between the closing plate and the inner surface of the blow box. This increases the energy saving achieved by the device. The force pressing the closing plate against the sealing member can be generated by an actuator 12.

[0029] According to a preferred embodiment, the surface area of ​​the closing plate part on the first side of the shaft has a different size than the surface area of ​​the closing plate part on the other side of the shaft, and the closing plate part with the larger surface area is pressed against the sealing part from its surface on the end side of the blow box. In this case, the air pressure difference formed between the different sides of the closed closing plate in the blow box also presses the closing plate against the sealing part. This ensures the function of the device and keeps the closing plate tightly against the sealing part even in the absence of the force generated by the above-mentioned actuator.

[0030] In terms of reliable function, size and durability of the device, it is important that the forces affecting the rotation of the shaft are minimal. It is therefore preferred that the shaft is supported by the blow box via bearings 9. Preferably, the bearings are sliding bearings, by using which air can be easily prevented from leaking through the gaps in the shaft and the structurally required openings of the shaft on the blow box side. It is also preferred that the actuators are connected to the shaft from both ends of the shaft substantially in the middle of the shaft length, at a distance equal to at least 1 / 3 of the shaft length. Figure 3 and 4 As shown, the actuator may be connected to the shaft, for example, by a belt.

[0031] Preferably, air is fed into the blow box from only one end of the blow box. Further preferably, the closing line formed by the shaft and the closing plate connected thereto is located at a distance equal to half the length of the blow box from one end of the blow box, the blow box being provided with blowing holes, from which end the air is fed into the blow box.

[0032] exist Figure 2-4 In the embodiment of the invention, the same blow box has two closed lines formed by a shaft and a closed plate attached thereto, the positions of these closed lines along the length of the blow box being different. By increasing the number of closed lines from one, more steps of reducing the blowing width are achieved. It is important for the invention that there is at least one closed line.

[0033] Figure 1-5 The equipment is usually used as follows: When loading the glass onto the loading platform before the heating furnace, the loading width to be achieved is taken into account. Assume that this width is narrower than the temporarily selected blowing width (i.e. Figure 2 If the distance WA or WB in the blowing box is narrow, the blowing width is narrowed by closing the blowing width of the blowing box by a closing plate, and the glass is positioned on the roller track so that it does not extend to the closed area of ​​the blowing width.

[0034] The glass can also always be loaded in the loading area to the edge of the side, from which the air is discharged into the blow box. In this case, if the width of the glass does not extend to the closing plate, the control system of the convection cooler closes the blowing width of the blow box by means of the closing plate of the invention. The control system receives information about the width of the glass, for example, from an automatic glass width measuring device. Such devices are well known in the art. Such devices can be, for example, a row of capacitive sensors between the loading platform and the heating furnace.

[0035] The present invention can also be applied to convection coolers in which the position of supplying air to the blow box is in the middle of the length of the blow box. Also in this case, when the glass is loaded to the other edge of the blowing width as described above, the blowing width can be narrowed by a closed line formed by a continuous closing plate on the same axis. On the other hand, in this case, there are two closed lines on different sides of the supply position, and the glass can be loaded to the middle area of ​​the blowing width, which is preferred in some applications.

[0036] The advantage of removing unnecessary blowing (i.e., for the width not occupied by glass in the convection cooler) is energy saving. When the blowing length of the blow box is closed, the input power of the blower motor will be reduced even if the speed of the blower motor and the speed of the blower impeller remain unchanged. In this case, the blowing pressure in the open length of the blow box (i.e., the blowing length) is also increased. Reducing the blowing area can also achieve a greater maximum blowing pressure, i.e., the cooling efficiency achieved by the convection cooler is increased. For example, this is useful in the tempering of even thinner glass. Tempering thinner glass sheets can be performed by closing the plate to temporarily narrow the blowing width. Obviously, narrowing in this case reduces the maximum size of the glass or the glass load.

[0037] In a preferred method, the rise in blowing pressure caused by the closing plate in the closed position along the length of the blow box upstream of the closing plate is compensated by reducing the rotational speed of the blower. This further reduces the input power to the blower motor, thereby increasing the energy saving effect. The required speed change can be based on data from a device measuring the blowing pressure, i.e. the air overpressure in the blow box, or can be calculated theoretically using the blower equation. The achievable temporary percentage reduction in the blower motor input power is equal to the temporary percentage reduction in the blowing width at its maximum value, i.e. at Figure 3 In the case of 100% x (WA / W) or 100% x (WB / W). When the device leakage is closed, the percentage of input power drop decreases. The energy saving, such as annual energy saving, depends on the utilization rate of the convection cooler and the thickness of the glass to be cooled, for example.

[0038] Preferably, when changing the position of the closing plate, the blowing pressure in the blowing box is reduced. This increases the durability of the device, because in this case, during the stage of changing the position, it will not be subjected to sudden forces exerted on the closing plate by the pressure difference.

[0039] The energy savings achieved by this method are mainly affected by the structure of the device. Leakage from the gap between the closing plate and the inner surface of the blow box will reduce energy savings. Therefore, the above-mentioned structure for reducing leakage disclosed in the device description is the preferred solution.

[0040] In the foregoing text and in the claims, glass refers to sheet glass, ie glass sheets.

[0041] A glass load can consist of one glass, continuous glass and parallel glass. For the purposes of this invention, the width of a glass and the width of a glass load refer to the same thing.

Claims

1. A device for reducing the blowing width of a glass convection cooler, wherein the convection cooler comprises blowing boxes (2) on both sides of the glass (G), the blowing boxes (2) are continuous in the moving direction of the glass, and air is discharged from the blowing holes (7) of the blowing boxes toward the glass to be cooled, characterized in that: The device comprises several closing plates (5a, 5b) in a series of said blow boxes, and an actuator (12), said closing plates being connected to the same shaft (4), said shaft being arranged to pass through the series of said blow boxes, said shaft being supported by said blow boxes, said shaft being able to be rotated by said actuator to prevent air from flowing into the ends of said blow boxes through said closing plates.

2. The device according to claim 1, characterized in that The closing plates (5a, 5b) of at least five consecutive blow boxes (2) are connected to the same shaft (4).

3. The device according to claim 1, characterized in that The closing plates (5a, 5b) of at least ten consecutive blow boxes (2) are connected to the same shaft (4).

4. The device according to any one of claims 1 to 3, wherein the axis is arranged relative to the closing plate so as to divide the axis into parts (A1, A2) located on different sides of the axis relative to the closing plate, It is characterized in that The device is equipped with a sealing member (6) dedicated to the closing plate, against which the edge of the closing plate (5a, 5b) is pressed in the closed position, so that the closing plate part on the first side of the shaft is pressed against the sealing member from its surface opposite to the closing plate part on the other side of the shaft.

5. The device according to claim 4, characterized in that The surface area (A1) of the closing plate portion on the first side of the shaft has a different size from the surface area (A2) of the closing plate portion on the other side of the shaft, and the closing plate portion with the larger surface area is pressed against the sealing component from its surface on the end (E) side of the blowing box.

6. The device according to claims 4 and 5, characterized in that The surface areas (A1, A2) of the closing plate portions on the first and second sides of the shaft are at least 1 / 3 of the entire surface area (A1+A2) of the closing plate.

7. A device according to any one of the preceding claims, characterised in that The shaft (4) is supported by the blow box via a bearing (9).

8. The device according to any one of the preceding claims, characterized in that The actuator (12) for driving the shaft to rotate is connected to the shaft (4) in the middle of the length of the shaft (4), that is, starting from the two ends of the shaft, the distance is equal to at least 1 / 3 of the length of the shaft.

9. The device according to claim 1, characterized in that Air is supplied to the blow box only from one end of the blow box, and a closed line formed by the shaft (4) and the closing plates (5a, 5b) attached thereto is located at a distance from the one end of the blow box of at least half the length (W) of the blow box, and the blow box is provided with a blowing hole to which air is supplied.

10. A method for temporarily reducing the blowing width of a glass convection cooler based on the width of the glass to be cooled, wherein in the convection cooler, the convection cooler is composed of blowing boxes (2) on both sides of the glass, the blowing boxes (2) are continuous in the moving direction of the glass, air is discharged from the blowing holes (7) of the blowing boxes toward the glass to be cooled, and the blowing widths of several consecutive blowing boxes are closed by rotating an axis (4) passing through the consecutive blowing boxes to change the position of a closing plate (5a, 5b) attached to the same axis.

11. The method according to claim 10, characterized in that The increase in blowing pressure caused by the closure plate rotating into the closed position along the length of the blow box upstream of the closure plate is compensated by reducing the rotational speed of the blower.

12. The method according to claim 10, characterized in that When the position of the closing plate is changed, the blowing pressure in the blowing box is reduced.

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