Powder supply device and method for manufacturing glass article

Abstract

A powder supply device (1) is provided with: a hopper (2); a feeder (3) having a transfer path (4) which transfers the powder (P) supplied from the hopper (2) in the lateral direction and in which a discharge port (7) is formed at the downstream end; and a door member (11) that opens and closes the transfer path (4), the door member (11) being held so as to be rotatable so as to be in an inclined attitude in which the door member (11) is inclined downward from the upstream side to the downstream side when the transfer path (4) is closed.

Description

Technical Field

[0001] The present invention relates to an improved technology for a door member of a feeder of a powder supply device and a method for manufacturing a glass article using the powder supply device. Background Art

[0002] In the field of powder supply, a powder supply device having a feeder such as a vibrating feeder or a screw feeder is used as a device for causing powder supplied from a hopper to be transferred laterally and dropped. In such a powder supply device, various improvements have been made to accurately drop a desired amount of powder.

[0003] As an example, patent document 1 discloses a technical solution, namely, a door plate is provided at the downstream end of the transfer path of a vibrating feeder, and the transfer path is closed by the door plate when the transfer of powder stops (when vibration stops), thereby preventing excess powder from spilling from the discharge port of the transfer path.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-70340 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In addition, the door plate disclosed in Patent Document 1 becomes vertical when the transfer of powder stops, thereby closing the transfer path and preventing excess powder from spilling from the discharge port (see the document). Figure 2 (b) and Figure 5 (b)). However, when the door plate blocks the powder in a vertical position, the powder layer will collapse if the angle of repose is taken into consideration. In this state, a strong force will act in the direction of pushing the door plate open due to the weight of the powder layer, so excess powder may still fall from the discharge port.

[0009] From the above viewpoints, an object of the present invention is to reliably prevent excess powder from scattering from a discharge port when the transfer of powder is stopped.

[0010] Solutions to Solve Problems

[0011] (1) A first aspect of the present invention made to solve the above-mentioned problems is a powder supply device, characterized in that the powder supply device comprises: a hopper; a feeder having a transfer path for transferring powder supplied from the hopper in a lateral direction and having a discharge port formed at a downstream end; and a door member for opening and closing the transfer path, the door member being rotatably held in an inclined posture in which the door member is inclined downward from an upstream side toward a downstream side when the transfer path is closed.

[0012] According to this structure, the door member is kept rotatable and becomes an inclined posture with the above-mentioned directionality when the transfer path is closed (hereinafter, simply referred to as the inclined posture). Therefore, at the time point when the transfer of the powder is stopped, the door member is affected by its own weight to press down the powder and close the transfer path. At this time, since the door member is in an inclined posture, the layer of powder blocked by the door member is difficult to collapse. If the layer of powder is in a state that is difficult to collapse, the force acting in the direction of pushing the door member open becomes weaker under the weight of the blocked layer of powder, so it is possible to reliably prevent excess powder from spilling from the discharge port. It should be noted that the door member can be in an inclined posture only under the action of its own weight when the transfer of the powder is stopped, but a spring or the like can also be used to adjust the pressing force acting from the door member to the layer of powder.

[0013] (2) In the configuration of (1) above, preferably, when the transfer of the powder is stopped, the gate member contacts the bottom of the transfer path to close the transfer path.

[0014] In this manner, it is possible to appropriately prevent excess powder from being scattered from the discharge port when the transfer of the powder is stopped.

[0015] (3) In the configuration of (1) above, preferably, when the transfer of the powder is stopped, the gate member contacts a lower end portion of the discharge port to close the transfer path.

[0016] In this manner, the gate member comes into contact with the lower end portion of the discharge port when the transfer of the powder stops, and thus it is possible to more reliably prevent excess powder from being scattered from the discharge port.

[0017] (4) In the configuration of (2) or (3) above, preferably, when the inclination angle of the gate member relative to the horizontal plane when the transfer of the powder is stopped is α and the repose angle of the powder is β, the relationship α≤β+30° is satisfied.

[0018] In this way, the angle of the inclination of the gate member when the transfer of the powder stops becomes an appropriate angle taking the angle of repose into consideration. This can more reliably prevent excess powder from spilling from the discharge port. It should be noted that the above relationship is preferably α≤β+15°, and more preferably α≤β.

[0019] (5) In any one of the above structures (1) to (4), the feeder may be a vibration feeder, and the powder may be a glass raw material.

[0020] (6) A second aspect of the present invention made to solve the above-mentioned problems is a method for manufacturing a glass article, characterized in that the method for manufacturing a glass article includes: a metering step of metering a glass raw material as a powder dropped from a discharge port of a transfer path in a feeder of a powder supply device having any one of the structures (1) to (5) above; a melting step of melting the glass raw material measured by the metering step to generate molten glass; and a forming step of forming the molten glass generated by the melting step.

[0021] According to this method, the accuracy of making the falling amount of the glass raw material equal to the target amount in the metering step is improved, so the metering step and the subsequent melting step and forming step can be smoothly performed.

[0022] Effects of the Invention

[0023] According to the present invention, it is possible to reliably prevent excess powder from being scattered from the discharge port when the transfer of the powder is stopped. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a longitudinal sectional side view showing the overall structure of the powder supply device according to the embodiment of the present invention.

[0025] Figure 2 It is a perspective view of the main parts showing the peripheral structure of a door member which is a component of the powder supply device according to the embodiment of the present invention.

[0026] Figure 3 This is a longitudinal sectional side view showing an enlarged view of a main part of the powder supply device according to the embodiment of the present invention.

[0027] Figure 4 This is a longitudinal sectional side view showing an enlarged view of a main part of the powder supply device according to the embodiment of the present invention.

[0028] Figure 5 This is a longitudinal sectional side surface showing an enlarged view of a main part of a first modified example of the powder supply device according to the embodiment of the present invention.

[0029] Figure 6 This is a longitudinal sectional side surface showing an enlarged view of a main part of a second modified example of the powder supply device according to the embodiment of the present invention. DETAILED DESCRIPTION

[0030] Hereinafter, a powder supply device and a method for producing a glass article according to embodiments of the present invention will be described with reference to the drawings.

[0031] Figure 1 1 is a longitudinal sectional side view showing the overall structure of the powder supply device 1. As shown in the figure, the powder supply device 1 includes a hopper 2 and a feeder 3 provided at a lower portion of the hopper 2.

[0032] The hopper 2 stores powder P in the internal space. In the present embodiment, the powder P is glass raw material, but is not limited thereto. The glass raw material is not limited to a mixed raw material of multiple varieties and brands mixed in order to obtain a glass of a desired composition, but may also be a single raw material composed of a single variety and brand before mixing. A supply port 2a for supplying the powder P to the feeder 3 is formed at the lower end of the hopper 2. It is preferred that a stirring mechanism such as gears (not shown) is provided in the internal space of the hopper 2.

[0033] The feeder 3 includes: a transfer path 4 that transfers the powder P supplied from the hopper 2 in a lateral direction (preferably in a horizontal direction); and a vibration mechanism 6 that imparts vibration to a transfer path wall 5 forming the transfer path 4. The feeder 3 is a vibrating feeder in this embodiment. Therefore, the powder P is transferred toward the downstream side (the side in the direction of arrow A) under the action of vibration.

[0034] The conveying path wall 5 is composed of a bottom wall portion 5a extending in the horizontal direction, two side wall portions 5b extending in the vertical direction, and an upper wall portion 5c formed by a cover covering the upper portion and extending in the horizontal direction. Therefore, the passage cross section of the conveying path 4 is rectangular. It should be noted that the bottom wall portion 5a is formed integrally with the two side wall portions 5b, but the cover (upper wall portion 5c) can be removed from the side wall portion 5b.

[0035] A discharge port 7 for discharging the powder P is formed at the downstream end of the conveying path 4. In the present embodiment, a drop guide path 8 connected to the discharge port 7 is provided. The guide path wall 9 forming the drop guide path 8 is composed of an upper extension wall portion 9a, two side extension wall portions 9b, a first end wall portion 9c and a second end wall portion 9d. The upper extension wall portion 9a extends from the upper wall portion 5c toward the downstream side. The two side extension wall portions 9b extend from the two side wall portions 5b toward the downstream side and extend downward from their extension portions. The first end wall portion 9c is connected to the downstream end portions of the upper extension wall portion 9a and the two side extension wall portions 9b. The second end wall portion 9d extends downward from the downstream end of the bottom wall portion 5a and is connected to the upstream end portions of the extension portions extending downward of the two side extension wall portions 9b.

[0036] A meter 10 for measuring the falling amount of the powder P is provided below the falling guide path 8. Therefore, the powder P discharged from the discharge port 7 of the transfer path 4 and falling is supplied to the meter 10. And, when the meter 10 shows that the falling amount of the powder P is consistent with the target amount, this is detected by the sensor and the operator, and the vibration given from the vibration mechanism 6 to the transfer path wall 5 of the feeder 3 is stopped. When the vibration stops, the transfer of the powder P in the transfer path 4 is stopped.

[0037] A plate-shaped door member (hinged door) 11 is provided in the conveying path 4. The door member 11 is maintained in an inclined posture (hereinafter referred to as the inclined posture) in which it is inclined downward from the upstream side to the downstream side. Figure 1 The conveying path 4 is kept in an inclined posture in both cases when the downstream end is closed as indicated by the solid line in the figure and when it is opened as indicated by the dashed line in the figure. The door member 11 can be formed of various metals, resins, etc., but is formed of stainless steel in the present embodiment.

[0038] The door member 11 is, for example, Figure 2 As shown in the figure, a bearing member 12 is mounted on the upper end (upstream end) of the gate member 11, and a support shaft 13 is inserted through the shaft hole of the bearing member 12. The support shaft 13 is fixed to the lower ends of two pillars 14 extending in the up-down direction. The two pillars 14 are fixed to the upper wall 5c in a state where they penetrate the upper wall 5c. As a result, the gate member 11 is kept rotatable around the support shaft 13 located at the upper part of the transfer path 4, and is in an inclined posture under the action of its own weight.

[0039] Figure 3 This is an enlarged longitudinal sectional side view of the main part showing the state when the vibration of the conveying path wall 5 stops and the conveying of the powder P in the conveying path 4 stops. As shown in the figure, when the conveying of the powder P stops, the gate member 11 rotates in the clockwise direction C around the support shaft 13 under the action of its own weight, so that the lower end 11a of the gate member 11 contacts the downstream end of the bottom surface 4a of the conveying path 4 as shown in the figure. In detail, the lower end 11a of the gate member 11 contacts the downstream end 4aa of the bottom surface 4a of the conveying path 4, that is, the lower end of the discharge port 7.

[0040] When the inclination angle of the door member 11 relative to the horizontal plane is set to α, and the angle of repose of the powder P is set to β, the relationship of α≤β+30° is satisfied. If this relationship is met, the transfer is stopped and the layer of powder P blocked by the door member 11 is difficult to collapse. If the layer of powder P is in a state that is difficult to collapse, the force acting in the direction of pushing the door member 11 open becomes weaker under the action of the weight of the blocked layer of powder P. As a result, it is possible to reliably prevent excess powder from spilling from the discharge port 7 and being supplied to the meter 10. Taking this into consideration, the above relationship is more preferably α≤β+15°, and more preferably α≤β. It should be noted that, in the case of glass raw materials, the angle of repose of the powder P is, for example, 10° to 40°.

[0041] Figure 4 1 is an enlarged longitudinal sectional side view of the main part showing the state when the transfer path wall 5 vibrates and the powder P is transferred in the transfer path 4. As shown in the figure, when the powder P is transferred, the powder P is forcibly transferred toward the downstream side under the action of vibration, so the pushing force from the powder P acts on the lower surface 11b of the door member 11. As a result, the door member 11 overcomes its own weight and rotates in the counterclockwise direction D around the support shaft 13. As a result, the door member 11 becomes a state of being pushed open as shown in the figure. At this time, the inclination angle of the door member 11 relative to the horizontal plane is smaller than the inclination angle α when the transfer is stopped. Therefore, a strong force does not act on the layer of the transferred powder P from the door member 11 in the direction opposite to the transfer direction. In other words, the force from the door member 11 that acts in the direction that hinders the transfer of the powder P becomes weaker. Thus, the powder P falls smoothly from the discharge port 7 and the supply amount of the powder P per unit time (the falling amount of the powder P from the discharge port 7 ) is less likely to vary. As a result, the supply amount can be stabilized.

[0042] Next, a method for producing a glass article according to an embodiment of the present invention will be described.

[0043] The manufacturing method of the glass article includes a metering step, a melting step and a forming step. The metering step is a step of metering the glass raw material as the powder P dropped from the discharge port 7 of the transfer path 4 in the above-mentioned feeder 3. The melting step is a step of melting the glass raw material measured in the metering step to generate molten glass. The forming step is a step of forming the molten glass generated in the melting step. In the forming step, for example, a glass ribbon is formed by an overflow method. The glass plate cut out from the formed glass ribbon is used as a substrate or a cover plate in displays such as liquid crystal displays and organic EL displays.

[0044] According to the method for producing a glass article, the accuracy of making the falling amount of the glass raw material match the target amount in the measuring step is improved, so that the variation of the glass composition is small and a high-quality glass article can be obtained.

[0045] As mentioned above, the powder supply device 1 and the method for producing a glass article according to the embodiment of the present invention have been described, but the present invention is not limited thereto, and various modifications can be made without departing from the gist of the invention.

[0046] In the above embodiment, the case where the powder P is filled or substantially filled in the transfer path 4 (a case where a large amount of powder P is transferred) is exemplified. However, in the case where a small amount of powder P is transferred or a minute amount of powder P is transferred, Figure 5 As shown, a large gap is provided between the layer of powder P and the upper surface 4b of the conveying path 4. In this case, a baffle or the like for adjusting the supply amount of powder P is preferably provided at an intermediate position in the conveying direction of the powder P in the conveying path 4.

[0047] In the above embodiment, the case where the lower end portion 11a of the gate member 11 contacts the lower end 4aa of the discharge port 7 when the transfer of the powder P is stopped is exemplified, but Figure 5 As shown, the lower end 11a of the gate member 11 contacts the lower end 4aa of the bottom surface 4a of the transfer path 4 at a position upstream of the downstream end (lower end of the discharge port 7). From the perspective of more reliably preventing the spillage of excess powder, it is preferred that the gate member 11 contacts the lower end 4aa of the discharge port 7.

[0048] You can also Figure 6 As shown in the figure, when the transfer of the powder P stops, the lower surface 11b of the gate member 11 contacts the lower end 4aa of the discharge port 7. When the lower end 11a of the gate member 11 contacts the lower end 4aa of the discharge port 7, if the position of the gate member 11 is offset, the lower end 11a of the gate member 11 may not contact the lower end 4aa of the discharge port 7, but may contact the downstream end of the bottom surface 4a of the transfer path 4. If the lower surface 11b of the gate member 11 contacts the lower end 4aa of the discharge port 7, the gate member 11 can be brought into contact with the lower end 4aa of the discharge port 7 even if the position of the gate member 11 is offset. Therefore, it is preferable to make the lower surface 11b of the gate member 11 contact the lower end 4aa of the discharge port 7.

[0049] In the above embodiment, the gate member 11 becomes inclined only by its own weight when the transfer of the powder P stops, but a spring or the like may be used to adjust the pressing force acting from the gate member 11 to the layer of the powder P. In addition, in order to adjust the pressing force, the gate member 11 may be provided with a counterweight. Furthermore, a plurality of gate members 11 of different masses may be prepared, and the pressing force may be adjusted by replacing the gate member 11.

[0050] Example

[0051] The following is an explanation of the embodiments and comparative examples of the present invention. Table 1 below shows Embodiment 1 and Embodiment 2 and the comparative example. In all tests, the powder P uses barium chloride as a glass raw material, and its repose angle β is 20°. The target amount is set to 3 kg, and the allowable range is set to ±0.02 kg. In each test, 10,000 measurements are performed, and the frequency of the number of times exceeding the allowable range is calculated. In Table 1 below, "angle α of the door member" means the angle α of the door member described above. Figure 3 The door member 11 is shown with an inclination angle α.

[0052] Table 1

[0053]

[0054] According to the above-mentioned Table 1, in the comparative example, the frequency of the number of times exceeding the allowable range is 0.05%. In Examples 1 and 2, the frequency of occurrence can be reduced by setting the door member 11 to an inclined posture. In Example 1, compared with Example 2, by making the inclination angle α of the door member 11 close to the repose angle β, the measurement error will not exceed the allowable range and no problem will occur. It should be noted that, considering the above results, it can be inferred that even if the angle α of the door member is larger than β+15°, if it is an angle moderately smaller than 90°, such as β+30°, the measurement error will become smaller and no problem will occur.

[0055] Description of Reference Numerals

[0056] 1 Powder supply device

[0057] 2 Hopper

[0058] 3 feeder

[0059] 4 Transfer route

[0060] 4a Bottom surface of the transfer path (bottom of the transfer path)

[0061] 4aa Downstream end of the bottom surface of the transfer path (lower end of the discharge port)

[0062] 7 Exhaust port

[0063] 11 Door components

[0064] Powder

[0065] α Tilt angle.

Claims

1. A powder supply device, characterized in that: The powder supply device comprises: a hopper; a feeder having a transfer path for transferring the powder supplied from the hopper in a lateral direction and having a discharge port formed at a downstream end; and a door member for opening and closing the transfer path. The gate member is rotatably held so as to assume an inclined posture in which the gate member is inclined downward from the upstream side toward the downstream side when the conveying path is closed.

2. The powder supply device according to claim 1, characterized in that: When the transfer of the powder is stopped, the gate member comes into contact with the bottom of the transfer path to close the transfer path.

3. The powder supply device according to claim 1, characterized in that: When the transfer of the powder is stopped, the gate member comes into contact with the lower end portion of the discharge port to close the transfer path.

4. The powder supply device according to claim 2, characterized in that: When the inclination angle of the gate member with respect to the horizontal plane when the transfer of the powder is stopped is α and the repose angle of the powder is β, the relationship of α≤β+30° is satisfied.

5. The powder supply device according to any one of claims 1 to 4, characterized in that: The feeder is a vibrating feeder.

6. The powder supply device according to any one of claims 1 to 4, characterized in that: The powder is glass raw material.

7. A method for manufacturing a glass article, characterized in that: The method for manufacturing the glass article includes: a metering step of metering the glass raw materials dropped from the discharge port of the transfer path in the feeder of the powder supply device according to claim 6; a melting step of melting the glass raw materials measured by the metering step to generate molten glass; and a forming step of forming the molten glass generated by the melting step.

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