Heating device and heating method for a vacuum drying machine

Abstract

The application discloses a heating device and a heating method of a vacuum drying machine, which comprises a heating main plate, a plurality of guide sleeves are installed on the heating main plate, and lifting needles are slidably connected to the guide sleeves; the heating main plate can move up and down to drive the guide sleeves to move synchronously, so that the lifting needles can move up and down relative to the guide sleeves; the lifting needles are provided with needle rod sleeves, the needle rod sleeves are fixedly provided with heating narrow plates, and the upper end surfaces of the heating narrow plates and the upper end surfaces of the heating main plate are provided with rough surfaces; the rough surfaces comprise a plurality of convex points, a plurality of recesses which are in communication with each other are formed between the adjacent convex points, and the heating narrow plates are inserted into the guide sleeves when the heating narrow plates are located at the lower end limit positions. The application provides a heating device and a heating method of a vacuum drying machine, and improves the drying effect and the screen glass forming quality.

Description

Technical Field

[0001] This invention relates to the field of vacuum drying technology, and more specifically, to a heating device and heating method for a vacuum dryer. Background Technology

[0002] After cleaning, screen glass may retain solvents such as pure water, isopropanol, and anisole on its surface and inside crevices. These require vacuum drying to remove the residual liquids and prevent surface defects such as watermarks, white spots, and uneven drying. Currently, vacuum drying heating devices employ a lifting mainboard paired with a narrow plate that can move vertically relative to the mainboard. When the lifting narrow plate is above the mainboard, it supports the newly loaded screen glass. After the mainboard rises, the narrow plate becomes flush with the heating mainboard, working together to support and heat the screen glass.

[0003] Existing heating motherboards are mostly smooth flat structures with the screen glass tightly bonded to the board surface. Heating takes place in a vacuum environment, where heat conduction plays a major role. Due to the relative movement between the heating motherboard and the narrow plate, there is a gap between them. Gas can easily accumulate in this gap, causing a significant difference in the heating temperature of the screen glass at the gap compared to other locations. This results in uneven contact temperature and inconsistent evaporation rates of solvent vapors, ultimately leading to the formation of fixed strip-shaped watermarks with varying film thicknesses or morphologies on the glass surface. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a heating device and heating method for a vacuum dryer, thereby improving the drying effect and the quality of screen glass forming.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a heating device for a vacuum dryer, comprising a heating main board, a plurality of guide sleeves installed on the heating main board, the guide sleeves being inserted into the heating main board, and a lifting needle slidably connected to the guide sleeves. The heating main board can move up and down to drive the guide sleeves to move synchronously, thereby enabling the lifting needle to move up and down relative to the guide sleeves. A needle rod sleeve is installed at the upper end of the lifting needle, and a heating narrow plate is fixedly installed at the upper end of the needle rod sleeve. When the heating main board is at its upper limit position, the upper end surface of the heating narrow plate is flush with the upper end surface of the heating main board. When the heating main board is at its lower limit position, the heating narrow plate is above the heating main board. Both the upper end surface of the heating narrow plate and the upper end surface of the heating main board are provided with rough surfaces, the rough surfaces including a plurality of protrusions, and a plurality of interconnected grooves are formed between adjacent protrusions. When the heating narrow plate is at its lower limit position, the heating narrow plate is inserted into the guide sleeve. The distance between two adjacent protrusions is 10 micrometers to 100 micrometers, and the gap between the heating narrow plate and the guide sleeve is 20 micrometers to 50 micrometers.

[0006] The present invention is further configured such that the upper end of the protrusion is arc-shaped.

[0007] The present invention is further configured such that the guide sleeve is inserted into the heating main board and the two are fixedly connected, the upper end surface of the guide sleeve is flush with the upper end surface of the heating main board, and the upper end surface of the guide sleeve is also provided with a rough surface.

[0008] The invention is further configured such that a radiant heat source is installed on the top of the lifting needle, the heat radiation direction of the radiant heat source is directed towards the heating narrow plate, and a temperature measuring component is installed on the heating narrow plate.

[0009] The invention is further configured such that the heating main board has multiple first through holes and multiple second through holes, the upper part of the guide sleeve is inserted into the first through hole, the upper end of the guide sleeve is provided with a countersunk hole, and the heating narrow plate is inserted into the countersunk hole when it is at the lower limit position.

[0010] The invention is further configured such that a heating rod is fixedly mounted on the heating main board, the upper part of the heating rod is inserted into the second through hole, the heating rod and the second through hole are arranged in a one-to-one correspondence, the heating rod and the second through hole are coaxially mounted, and the gap between the upper outer wall of the heating rod and the second through hole is less than 100 micrometers.

[0011] The invention is further configured such that a positioning seat is mounted on the heating main board, the positioning seat is fixedly connected to the heating rod, the positioning seat has a first channel, the positioning seat is fixedly connected to the heating main board by a fastener, the fastener passes through the first channel and is inserted into the heating main board, the diameter of the first channel is larger than the outer diameter of the part of the fastener passing through the first channel, so that the positioning seat can be adjusted in position, thereby adjusting the gap between the upper outer wall of the heating rod and the second through hole.

[0012] The present invention also adopts the following technical solution: a heating method, which uses the heating device of a vacuum dryer to heat the screen glass, including the following steps: Step S1: the heating main board is located at the lower limit position, the heating narrow plate is located above the heating main board, and the screen glass is placed on the upper end of multiple heating narrow plates; Step S2: the heating main board is moved upward to place the screen glass on the upper surface of the heating main board; Step S3: the screen glass is heated to 60°C under vacuum to make the residual liquid evaporate.

[0013] The present invention is further configured such that when the screen glass is placed on the upper end of the plurality of heating narrow plates, the temperature of the heating narrow plates is less than 35°C.

[0014] In summary, the present invention has the following beneficial effects:

[0015] By creating rough surfaces with arc-shaped protrusions on the upper surfaces of the heating main plate, heating narrow plate, and guide sleeve, interconnected mesh-like groove exhaust channels are formed between adjacent protrusions. During vacuum evacuation, the gas between the glass and the heating main plate is preferentially discharged along the large mesh-like grooves, preventing it from accumulating in the narrow gaps between the plates. This fundamentally avoids the formation of temperature differences that cause streaks of watermarks due to gas accumulation in the gaps. Attached Figure Description

[0016] Figure 1 This is a three-dimensional schematic diagram of a vacuum dryer;

[0017] Figure 2 This is a cross-sectional schematic diagram of the heating motherboard in the embodiment;

[0018] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0019] Figure 4 This is a diagram showing the rising state of the lifting pin in the embodiment;

[0020] Figure 5 This is a diagram showing the positional relationship between the screen glass and the rough surface in the embodiment;

[0021] Figure 6 This is a top view of the heating motherboard in one embodiment;

[0022] Figure 7 This is another cross-sectional view of the heating motherboard in the embodiment;

[0023] Figure 8 for Figure 7 Enlarged view of point C in the middle;

[0024] Figure 9 This is another top view of the heated motherboard in the embodiment.

[0025] Reference numerals: 1. Heating main board; 11. First through hole; 12. Second through hole; 2. Lifting needle; 21. Needle bar sleeve; 22. Heating narrow plate; 23. Radiant heat source; 24. Temperature measuring component; 3. Guide sleeve; 31. Countersunk hole; 4. Screen glass; 5. Positioning seat; 51. First channel; 52. Second channel; 53. Third channel; 54. Fourth channel; 55. Fifth channel; 6. Fastener; 7. Heating rod; 71. Extension rod; 71. First protrusion; 711. Second protrusion; 712. Vacuum dryer body; 8. Rough surface; 9. Protrusion; 91. Groove; 92. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1:

[0028] like Figures 1-6As shown, this embodiment discloses a heating device for a vacuum dryer, used for vacuum drying of screen glass 4, which is a display screen component. Figure 1 As shown, the heating device includes a heating main board 1, which is located inside the vacuum dryer body 8. The heating main board 1 is heated by an embedded heating wire. The vacuum dryer body 8 includes a vacuum pump to create a near-vacuum environment for the heating main board 1, where liquids evaporate more easily.

[0029] like Figure 2 , Figure 3 As shown, the heating main board 1 moves up and down via a drive device (screw drive). Multiple guide sleeves 3 are installed on the heating main board 1, and the guide sleeves 3 are inserted into the heating main board 1. A lifting pin 2 is slidably connected to the guide sleeve 3, and the lifting pin 2 can move up and down relative to the inner wall of the guide sleeve 3. A gravity hammer is suspended at the bottom of the lifting pin 2. When the heating main board 1 is at its lower limit position, the top of the lifting pin 2 extends out of the heating main board 1, and the bottom end of the gravity hammer at the bottom of the lifting pin 2 is supported by a support component. When the heating main board 1 is at its upper limit position, the top of the lifting pin 2 extends into the heating main board 1.

[0030] like Figure 3 As shown, the upper end of the heating main board 1 has a first through hole 11. The upper part of the guide sleeve 3 is inserted into the first through hole 11, and the lower part of the guide sleeve 3 is fixedly connected to the heating main board 1. Since the two are in contact, the heating main board 1 is heated while the guide sleeve 3 is also heated. Both the guide sleeve 3 and the heating main board 1 are made of metal, which facilitates heat conduction.

[0031] The upper end of the guide sleeve 3 is provided with a countersunk hole 31, and the upper end of the lifting needle 2 is equipped with a needle bar sleeve 21. The upper end of the needle bar sleeve 21 is fixedly installed with a heating narrow plate 22. When the heating main board 1 is at the lower limit position, the heating narrow plate 22 is located above the heating main board 1 to support the screen glass 4; when the heating main board 1 is at the upper limit position, the upper surface of the heating narrow plate 22 is flush with the heating main board 1.

[0032] like Figure 6 The distribution of the lifting pins 2 is shown, and the spacing and number of them are determined according to the different sizes and types of screen glass 4.

[0033] The upper end face of the heating narrow plate 22, the upper end face of the heating main plate 1, and the upper end face of the guide sleeve 3 are all provided with rough surfaces 9, such as... Figure 5As shown, the rough surface 9 includes multiple protrusions 91, the upper end of which is approximately arc-shaped. Multiple interconnected grooves 92 are formed between adjacent protrusions 91. The protrusions 91 are used to abut against the screen glass 4. The screen glass 4 is supported and heat is conducted through the multiple protrusions 91, resulting in basically uniform heating of the screen glass 4. Local temperature differences are not easily observed, and the heating effect is basically achieved by the heat conduction method when the motherboard 1 is in a planar state (non-rough surface).

[0034] The function of groove 92:

[0035] Function 1: The groove 92 forms a mesh airflow channel, preventing the formation of a concentrated gas accumulation area under the screen glass 4, thus improving the temperature difference problem caused by the heating of the screen glass 4.

[0036] Function 2: The groove 92 prevents the bottom of the screen glass 4 from fitting too tightly with the heating motherboard 1, reducing the separation force and the risk of breakage during separation.

[0037] The spacing between two adjacent bumps 91 ranges from 10 to 100 micrometers, and the height of bump 91 ranges from 15 to 25 micrometers. The bumps 91 are formed using a process of etching, passivation, sandblasting, and grinding. When aluminum alloy is used as the material for the heating narrow plate 22, a phosphoric acid-based low-side-etching formulation (phosphoric acid, nitric acid, glacial acetic acid, ultrapure water, triazole corrosion inhibitors, and low-foaming surfactants) is used as the etching solution. When stainless steel is used as the material for the heating narrow plate 22, a ferric chloride solution is used. Grinding is used to control the consistency of the top height of the bumps 91. The arc shape of the bumps 91 is formed after adding lubricant during the grinding process, and the sharp edges are preferentially ground down.

[0038] Since the heating narrow plate 22 and the guide sleeve 3 need to move relative to each other, there will inevitably be a gap between them. When some of the gas on the bottom surface of the screen glass 4 gathers at the gap, a temperature difference occurs between the gas and the heating narrow plate 22. Uneven heating of the screen glass 4 can easily lead to watermarks, affecting the uniformity of film thickness and the quality of film formation. Therefore, by setting grooves 92, which are interconnected and connected to the vacuum cavity of the vacuum dryer body 8, the volatilized gas can be released in a timely manner.

[0039] When the heating narrow plate 22 is at its lower limit position, it is inserted into the guide sleeve 3. The gap between the heating narrow plate 22 and the guide sleeve 3 is 20 to 50 micrometers, and the gap on one side is 10 to 25 micrometers. This gap value falls within the smaller range of the distance between two adjacent protrusions 91. Since gas always preferentially flows from the wider channel, and combined with the fact that hot air tends to flow upward, this arrangement makes it less likely for volatile gas to remain excessively in the gap between the heating narrow plate 22 and the guide sleeve 3, thus preventing it from condensing and forming watermarks on the screen glass 4.

[0040] The upper surface of the guide sleeve 3 is flush with the upper surface of the heating main plate 1. A radiant heat source 23 is installed on the top of the lifting needle 2. The heat radiation direction of the radiant heat source 23 points towards the heating narrow plate 22. A temperature measuring component 24 (thermocouple) is installed on the heating narrow plate 22 to detect the temperature.

[0041] Example 2:

[0042] like Figures 7-9 As shown, and in combination Figure 3 , Figure 5 The difference from Embodiment 1 is that the heating mainboard 1 also has multiple second through holes 12, and the diameter of the countersunk hole 31 is smaller than the diameter of the second through hole 12. A heating rod 7 is fixedly installed on the heating mainboard 1. The heating rod 7 radiates heat from the bottom. The upper part of the heating rod 7 is inserted into the second through hole 12. The heating rod 7 and the second through hole 12 are arranged in a one-to-one correspondence. The heating rod 7 and the second through hole 12 are coaxially installed. The upper end surface of the heating rod 7 is flush with the upper end surface of the heating mainboard 1. The heating rod 7 also has the same rough surface 9 as the heating mainboard 1 to support and heat the screen glass 4.

[0043] The gap between the upper outer wall of the heating rod 7 and the second through hole 12 is less than 100 micrometers.

[0044] When the diameter of the heating rod 7 is selected to be less than 15 mm, its outer diameter expands by less than 6 micrometers when heated to 60°C, so the gap will not be sealed. Similarly, since the diameter of the countersunk hole 31 is smaller than the diameter of the second through hole 12, the thermal expansion of the heating narrow plate 22 is smaller, so as to ensure that the gap is retained.

[0045] like Figure 8 As shown, the heating main board 1 is equipped with a positioning seat 5, which is located below the second through hole 12. The positioning seat 5 is fixedly connected to the heating rod 7. Specifically, the positioning seat 5 has a first channel 51, and at least two first channels 51 are provided along the circumference of the positioning seat 5. The positioning seat 5 is fixedly connected to the heating main board 1 by a fastener 6. The fastener 6 passes through the first channel 51 and is inserted into the heating main board 1. The diameter of the first channel 51 is larger than that of the fastener 6, so that the positioning seat 5 can be adjusted in position, thereby adjusting the gap between the upper outer wall of the heating rod 7 and the second through hole 12 to prevent the gap on one side from being too large.

[0046] The positioning seat 5 has a fourth channel 54, a third channel 53, and a second channel 52 arranged sequentially from top to bottom. The fourth channel 54 and the third channel 53 are countersunk holes. The diameter of the third channel 53 is larger than that of the second channel 52. The heating rod 7 includes an extension rod 71 located at the bottom. The extension rod 71 includes a first protrusion 711 extending radially outward and a second protrusion 712 located at the bottom. The first protrusion 711 is located inside the third channel 53, and the bottom surface of the first protrusion 711 abuts against the bottom surface of the third channel 53. The extension rod 71 passes downward through the second channel 52. The second protrusion 712 is threadedly connected to a pressure ring. The pressure ring presses against the bottom surface of the positioning seat 5 to fix the heating rod 7.

[0047] To address the issue of the relatively narrow air passage formed by the groove 92 and the low vacuum efficiency of the gas within the groove 92, the gap between the extension rod 71 and the second through hole 12 is increased. The second through hole 12 is connected to the groove 92 so that the gas within the groove 92 can be released through the second through hole 12.

[0048] The extension rod 71 also includes a fifth channel 55, which connects to the second through hole 12 via a fourth channel 54. The bottom of the fifth channel 55 is connected to an external negative pressure device (vacuum pump) via an air pipe to perform targeted evacuation of the second through hole 12. Simultaneously, by controlling the uniformity of the gap between the heating rod 7 and the second through hole 12 during installation, excessively narrow local air passages are prevented, thus forming a more stable exhaust channel and avoiding localized air blockage, thereby improving overall drying efficiency.

[0049] Example 3:

[0050] A heating method, using the heating device of the vacuum dryer in Embodiment 1 or Embodiment 2 to heat the screen glass 4, includes the following steps:

[0051] Step S1: The heating main board 1 is located at the lower limit position, and the heating narrow plate 22 is located above the heating main board 1. The screen glass 4 is placed on the upper end of the multiple heating narrow plates 22. In this state, the temperature of the heating narrow plate 22 is less than 35°C (cooled by air by introducing dry nitrogen into the inner cavity of the vacuum dryer body 8) to prevent local high temperature from forming at the contact position between the screen glass 4 and the heating narrow plate 22.

[0052] Step S2: The heated motherboard 1 is moved upward to place the screen glass 4 on the upper surface of the heated motherboard 1.

[0053] Step S3: Maintain a vacuum state in the external environment (i.e., the inner cavity of the vacuum dryer body 8) of the heating main plate 1, heating narrow plate 22 and heating rod 7;

[0054] Step S4: Simultaneously heat the main board 1, the narrow plate 22, and the heating rod 7 to 60°C and keep them warm so that the liquid remaining on the screen glass 4 can evaporate.

[0055] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A heating device for a vacuum dryer, characterized in that, The heating main board (1) is equipped with multiple guide sleeves (3). The guide sleeves (3) are inserted into the heating main board (1). A lifting needle (2) is slidably connected to the guide sleeves (3). The heating main board (1) can move up and down to drive the guide sleeves (3) to move synchronously, so that the lifting needle (2) can move up and down relative to the guide sleeves (3). A needle bar sleeve (21) is installed on the upper end of the lifting needle (2). A heating narrow plate (22) is fixedly installed on the upper end of the needle bar sleeve (21). When the heating main board (1) is at the upper limit position, the upper end surface of the heating narrow plate (22) is flush with the upper end surface of the heating main board (1). When the heating main board (1) is at the lower limit position, the heating narrow plate (22) is above the heating main board (1). Both the upper end surface of the heating narrow plate (22) and the upper end surface of the heating main board (1) are provided with coarse coating. The rough surface (9) includes multiple protrusions (91), and multiple interconnected grooves (92) are formed between adjacent protrusions (91). When the heating main board (1) is in the upper limit position, the heating narrow plate (22) is inserted into the guide sleeve (3), and the guide sleeve (3) is inserted into the heating main board (1) and the two are fixedly connected. The upper end face of the guide sleeve (3) is flush with the upper end face of the heating main board (1). The upper end face of the guide sleeve (3) is also provided with the rough surface (9). The distance between two adjacent protrusions (91) is 10 micrometers to 100 micrometers. The gap between the heating narrow plate (22) and the guide sleeve (3) is 20 micrometers to 50 micrometers. The single-sided gap between the heating narrow plate (22) and the guide sleeve (3) is 10 micrometers to 25 micrometers. This gap value is within the smaller range of the distance between two adjacent protrusions (91).

2. The heating device for a vacuum dryer according to claim 1, characterized in that, The upper end of the protrusion (91) is arc-shaped.

3. The heating device for a vacuum dryer according to claim 1, characterized in that, The top of the lifting needle (2) is equipped with a radiant heat source (23), the heat radiation direction of the radiant heat source (23) is directed towards the heating narrow plate (22), and the heating narrow plate (22) is equipped with a temperature measuring component (24).

4. The heating device for a vacuum dryer according to claim 1, characterized in that, The heating main board (1) is provided with multiple first through holes (11) and multiple second through holes (12). The upper part of the guide sleeve (3) is inserted into the first through hole (11). The upper end of the guide sleeve (3) is provided with a countersunk hole (31). When the heating narrow plate (22) is in the lower limit position, it is inserted into the countersunk hole (31).

5. The heating device for a vacuum dryer according to claim 4, characterized in that, The heating main board (1) is fixedly mounted with a heating rod (7). The upper part of the heating rod (7) is inserted into the second through hole (12). The heating rod (7) and the second through hole (12) are arranged in a one-to-one correspondence. The heating rod (7) and the second through hole (12) are coaxially mounted. The gap between the upper outer wall of the heating rod (7) and the second through hole (12) is less than 100 micrometers.

6. The heating device for a vacuum dryer according to claim 5, characterized in that, The heating main board (1) is equipped with a positioning seat (5), which is fixedly connected to the heating rod (7). The positioning seat (5) has a first channel (51). The positioning seat (5) is fixedly connected to the heating main board (1) by a fastener (6). The fastener (6) passes through the first channel (51) and is inserted into the heating main board (1). The diameter of the first channel (51) is larger than the outer diameter of the part of the fastener (6) that passes through the first channel (51), so that the positioning seat (5) can be adjusted to adjust the position, thereby adjusting the gap between the upper outer wall of the heating rod (7) and the second through hole (12).

7. A heating method, comprising heating a screen glass (4) using a heating device of a vacuum dryer as described in any one of claims 1-6, characterized in that, Includes the following steps: Step S1: The heating main board (1) is located at the lower limit position, the heating narrow plate (22) is located above the heating main board (1), and the screen glass (4) is placed on the upper end of the multiple heating narrow plates (22); Step S2: The heating main board (1) moves upward to place the screen glass (4) on the upper surface of the heating main board (1); Step S3: The screen glass (4) is heated to 60°C in a vacuum state to allow the residual liquid to evaporate.

8. A heating method according to claim 7, characterized in that, In step S1, when the screen glass (4) is placed on the upper end of the plurality of heating narrow plates (22), the temperature of the heating narrow plates (22) is less than 35°C.

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