Experimental device and method for simulating spraying of heat stabilizer of cellulose insulation paper

Abstract

The invention provides an experimental device and method for simulating spraying of a heat stabilizer of cellulose insulation paper. The device comprises a conveyor belt, an insulation paper web, a bracket and a spray head group, the insulating paper web is wound on the surface of the conveyor belt, and the nozzle group is mounted above the conveyor belt through the bracket. The method comprises the following steps: preparing a heat stabilizer solution; adjusting the height and horizontal included angle of the conveyor belt; rotating a central rotating shaft of the fog-type nozzle group to adjust a nozzle-paper web included angle, and opening a fog-type nozzle switch combination according to experiment requirements; hot water and the heat stabilizer solution respectively enter a pipeline for rinsing; winding insulation paper on the surface of the conveyor belt; marking at a position where the direction of a spray head intersects with the paper web, starting a conveying belt, and starting a water pump for spraying, so that the heat stabilizer solution is sprayed on the paper web; all switches are turned off, and the conveyor belt surface insulation paper sample is taken down. The process of spraying and adding the nitrogen-containing heat stabilizer in the conveying process of the pressing part of the insulation paper can be simulated.

Description

Technical Field

[0001] The present disclosure relates to the technical field of development of heat-upgraded cellulose paper insulation materials for transformers, and in particular to an experimental device and method for simulating the spraying of a heat stabilizer on cellulose insulation paper. Background Art

[0002] Oil-paper insulation is the primary insulating material for oil-immersed transformers. Natural cellulose insulation paper offers advantages such as environmental friendliness and excellent oil impregnation. However, the inherent molecular structure of natural fibers limits its long-term heat resistance to Class A (105°C), making it difficult to meet the high-reliability requirements of transformers. Nitrogen-containing substances such as dicyandiamide can be used as heat-resistant additives to thermally modify cellulose insulation paper. Nitrogen content, a key indicator for evaluating thermally modified paper, is typically required to be around 1%-4%.

[0003] Currently, laboratories typically use the rapid Kaeser method to produce small insulating paper sheets, adding nitrogen-containing heat stabilizers to the paper via coating. This method is inefficient for preparing modified insulating paper samples and struggles to ensure uniformity during the coating process. Insulating paper production lines typically use a method of spraying heat stabilizers into the press section of the paper machine for thermal modification, but this presents process challenges with low nitrogen content. The process methods and parameters for improving the retention of nitrogen-containing heat stabilizers are unclear. Experiments on insulating paper production lines are often sparsely scheduled and expensive, making them unsuitable for long-term experimental research.

[0004] Therefore, there is an urgent need for an experimental device that can efficiently and cost-effectively study the process of adding nitrogen-containing heat stabilizers, simulate the factors affecting the spray process in the press section of the insulating paper production paper machine, and obtain the optimal process parameters from aspects such as spray angle, paper machine speed, and solution concentration. Summary of the Invention

[0005] The technical solution adopted by the present disclosure to solve the technical problem is: a device for simulating the spraying of heat stabilizer on cellulose insulation paper, the device comprising: a conveyor belt, an insulation paper web, a bracket, and a nozzle group;

[0006] The insulating paper web is wound on the surface of the conveyor belt, and the nozzle group is installed above the conveyor belt through the bracket. The nozzle group is used to spray out the thermal stabilizer.

[0007] Preferably, the insulating paper web is cellulose insulating paper.

[0008] Preferably, the slope of the conveyor belt is adjustable.

[0009] Preferably, the conveyor belt is made of a flat, porous mesh belt or a diamond-shaped striped belt with fine grooves on the surface.

[0010] Preferably, the angle between the conveyor belt and the horizontal plane can be adjusted in the range of 0-45°.

[0011] Preferably, the speed v of the conveyor belt is in the range of 5-20 m / min.

[0012] Preferably, the bracket is installed 15 cm vertically above the midpoint of the length direction of the conveyor belt.

[0013] Preferably, the nozzle group is composed of at least 5 mist nozzles connected together, and each nozzle is designed with an independent control switch.

[0014] The present disclosure also provides a method for simulating a thermal stabilizer spray test on cellulose insulation paper, the method comprising the following steps:

[0015] S1. Prepare thermal stabilizer solution;

[0016] S2. Adjust the height and horizontal angle of the conveyor belt;

[0017] S3. Rotate the central axis of the mist nozzle group to adjust the nozzle-paper angle, and turn on the mist nozzle switch combination according to the experimental needs;

[0018] S4, allowing hot water and the heat stabilizer solution to enter the pipeline for rinsing respectively;

[0019] S5, cutting the insulating paper into paper sheets of uniform width and winding them on the surface of the conveyor belt;

[0020] S6. Mark the position where the nozzle direction intersects the paper web, start the conveyor belt, adjust the speed, and turn on the water pump to spray, so that the heat stabilizer solution is sprayed on the paper web;

[0021] S7. Turn off all switches and remove the insulation paper sample from the conveyor belt surface.

[0022] Preferably, the heat stabilizer solution is a nitrogen-containing heat stabilizer solution.

[0023] Preferably, no glue is used between the paper web and the conveyor belt.

[0024] Preferably, the water pump of the insulating paper is turned off after the conveyor belt moves for one cycle, and the surface of the insulating paper is sprayed only once.

[0025] The technical advantages of the present disclosure are as follows:

[0026] 1) Rapid and low-cost preparation of thermally modified insulating paper to achieve relatively uniform distribution of thermal stabilizers;

[0027] 2) Study the effects of process parameters such as spray angle on the retention rate of nitrogen-containing heat stabilizer to obtain the optimal process parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a front view of the structure design of the spray device in one embodiment of the present disclosure;

[0029] Figure 2 This is a side view of the structural design of the spray device in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] The following will refer to the attached Figures 1 to 2 Specific embodiments of the present disclosure are described in detail. Although specific embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Instead, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0031] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present disclosure, but the description is based on the general principles of the specification and is not used to limit the scope of the present disclosure. The scope of protection of the present disclosure shall be as defined by the attached claims.

[0032] To facilitate understanding of the embodiments of the present disclosure, further explanation will be given below using specific embodiments as examples in conjunction with the accompanying drawings, and the accompanying drawings do not constitute a limitation on the embodiments of the present disclosure.

[0033] The present disclosure provides an experimental device and method for simulating the spraying of a heat stabilizer on cellulose insulation paper, which can simulate the process of spraying and adding a nitrogen-containing heat stabilizer to the insulation paper during the conveying process in the press section.

[0034] In one embodiment, Figure 1 As shown, a simulated cellulose insulation paper heat stabilizer spraying experimental device includes: a solution container 1, a pressure pump 2, a conveyor belt support 3, a conveyor belt 4, a conveyor belt strip 5, an insulation paper sample 6, a nozzle 7, a support gantry 8, and a pipeline 9.

[0035] The insulating paper sample 6 is wound on the surface of the conveyor belt 4 , and the nozzle 7 is installed above the conveyor belt 4 through the supporting gantry 8 .

[0036] In another embodiment, a simulated cellulose insulation paper heat stabilizer spraying experimental device includes: a conveyor belt, an insulation paper web, a bracket, and a nozzle group; wherein, the conveyor belt is used to transmit the insulation paper web; the bracket is used to fix the nozzle group; and the nozzle group is used to spray the heat stabilizer on the insulation paper web.

[0037] Further:

[0038] ① The conveyor belt has an adjustable slope and is made of either a flat, perforated mesh belt or a diamond-shaped belt with fine grooves. The diamond-shaped belt has a flat surface and fine grooves, which can store excess water. The mesh belt is flat and is more effective in filtering out excess water.

[0039] ② The conveyor belt is greater than 75 cm in length and 30 cm in width, and its support bracket can be adjusted in height from 75 to 150 cm to adjust the slope. The angle between the conveyor belt and the horizontal plane can be adjusted from 0 to 45 degrees. The conveyor belt speed v range is 5 to 20 m / min.

[0040] ③ The insulating paper web is 30 cm wide and is wound on the surface of the conveyor belt.

[0041] ④ The bracket is used to fix the nozzle group, which is a mist nozzle group. The mist nozzle group is installed and fixed by the bracket 15 cm vertically above the midpoint of the conveyor belt along its length. The mist nozzle group consists of at least 5 mist nozzles connected by rigid pipes. The distance between the nozzles is approximately 6.6 cm, and each nozzle is designed with an independent control switch. The rigid pipes at both ends are in contact with the bracket and can be axially rotated 0-360°. The nozzle flow rate q ranges from 0.035 to 0.05 L / min.

[0042] ⑤ One end of the mist nozzle assembly is connected to a closed valve, and the other end is connected to a water pump through a pipe (hose or hard pipe), and then connected to a nitrogen-containing heat stabilizer solution container, which is placed on a heatable magnetic stirrer. The working pressure range of the water pump is 4-12 kg / cm 2 .

[0043] In another embodiment, the present disclosure further provides a method for simulating a thermal stabilizer spray test on cellulose insulation paper, comprising the following steps:

[0044] Step 1: Prepare a nitrogen-containing heat stabilizer solution with appropriate concentration and ratio and place it in a nitrogen-containing heat stabilizer container. Turn on the heating magnetic stirrer, stir appropriately and maintain the solution temperature within the range of 75°C-80°C.

[0045] Step 2: Adjust the height of the conveyor belt brackets and the horizontal angle of the conveyor belt. The height of the brackets can be adjusted from 75 to 150 cm, and the angle with the horizontal plane can be adjusted from 0 to 45°. When both the left and right brackets are 75 cm high, the angle with the horizontal plane is approximately 0°. When the left bracket is 75 cm high and the right bracket is 150 cm high, the angle with the horizontal plane is approximately 45°.

[0046] Step 3: Rotate the central axis of the mist nozzle group to adjust the nozzle-paper angle. The nozzle-paper angle can be adjusted within a range of (-90°, 90°). Turn on the mist nozzle switch combination according to experimental needs. You can set nozzles 1, 3, and 5 to open at intervals, with a nozzle spacing of 13.2 cm to simulate the actual paper machine spray device; or set nozzles 1, 2, 3, 4, and 5 to all open, with a nozzle spacing of 6.6 cm.

[0047] Step 4: Turn off all nozzle switches, turn on the pipe switch at the end of the mist nozzle group, turn on the water pump to adjust the working pressure, first rinse the pipe with 85°C hot water for 5 minutes, then allow the solution in step 1 to enter the pipe and rinse for 10 seconds, then turn off the water pump and turn off the pipe switch at the end of the mist nozzle group.

[0048] Step 5: Cut the insulating paper that has been placed in a vacuum oven at 105°C for 16 hours into 30 cm wide paper webs, wrap them around the conveyor belt, and glue the ends of the paper web together around the conveyor belt. Do not use glue between the paper web and the conveyor belt.

[0049] Step 6: Start the conveyor belt and adjust the speed. The conveyor belt speed can be adjusted in the range of 5-20 m / min.

[0050] Step 7: Turn on the water pump for spraying. After the conveyor belt has moved for one cycle, turn off the water pump and the surface of the insulating paper will only be sprayed once.

[0051] Step 8. Turn off all switches and remove the insulation paper sample from the conveyor belt surface.

[0052] Preferably, the adjustable range of the water pump working pressure is 4-12 kg / cm 2 .

[0053] Based on the experimental device and method for simulating the spraying of heat stabilizer for cellulose insulation paper proposed in this disclosure, a simulation experiment was conducted on the paper machine parameters of a certain insulation paper production workshop. Figure 2 As shown in the figure, the experimental principle is to achieve the same spray volume per unit area s (unit: mL / m 2 ):

[0054] (1)

[0055] Where q is the nozzle flow rate, in L / min; v is the vehicle speed, in m / min; l0 is the distance between the open nozzles, in cm.

[0056] The comparison of parameters between the simulated spray device and the paper machine spray device is shown in Table 1:

[0057] Table 1

[0058]

[0059] The comparison of nitrogen content (Kjeldahl method) of thermally modified insulating paper samples prepared by the simulated spraying device is shown in Table 2. In the sample number format "ab", a represents the paper web number, b represents the spray position (b=1 represents sampling at a distance of 10 cm from the edge of the conveyor belt, and b=2 represents sampling at a distance of 20 cm from the edge of the conveyor belt), and the solution consumption represents the consumption of nitrogen-containing heat stabilizer solution.

[0060] The differences in nitrogen content between the two paper webs at different spraying positions were 9.4% and 11.1%, respectively, indicating a relatively uniform distribution of nitrogen content.

[0061] For the two paper webs tested at different spray angles, the average nitrogen content at 0° spraying was higher than that at 45° spraying. Therefore, a smaller spray angle is more conducive to the absorption and retention of nitrogen-containing heat stabilizers.

[0062] The consumption of nitrogen-containing heat stabilizer for the two paper webs tested was less than 200 mL, and the consumption of nitrogen-containing heat stabilizer for a single sample preparation was relatively small.

[0063] The spraying time of the two paper webs tested was less than 2 min, and single sample preparation took less time.

[0064] Table 2

[0065]

[0066] The apparatus and method proposed in this disclosure simulate the process of spraying a heat stabilizer on cellulose insulation paper at low cost. The apparatus and method can be used to investigate the impact of spray process parameters, such as spray angle, on the retention rate of the nitrogen-containing heat stabilizer. This addresses the challenges of limited experimental scheduling and high costs associated with heat-resistant cellulose insulation paper production lines, and develops a process plan for adding nitrogen-containing heat stabilizers to insulation paper webs.

[0067] The above general description of the inventions and the description of their specific embodiments involved in this disclosure should not be construed as limiting the technical solutions of the inventions. Based on the disclosure of this disclosure, those skilled in the art may, without violating the constituent elements of the inventions involved, add to, subtract from, or combine the disclosed technical features in the above general description and / or the specific embodiments (including Examples) to form other technical solutions within the scope of protection of this disclosure.

Claims

1. A device for simulating the spraying of heat stabilizer on cellulose insulation paper, characterized in that: The device comprises: a conveyor belt, an insulating paper web, a bracket, and a nozzle group; The insulating paper web is wound on the surface of the conveyor belt, and the nozzle group is installed above the conveyor belt through the bracket. The nozzle group is used to spray out the thermal stabilizer.

2. The device according to claim 1, characterized in that Preferably, the slope of the conveyor belt is adjustable.

3. The device according to claim 1, wherein The insulating paper web is cellulose insulating paper.

4. The device according to claim 2, characterized in that The angle between the conveyor belt and the horizontal plane can be The adjustment range is 0-45°.

5. The device according to claim 1, wherein The speed v of the conveyor belt ranges from 5 to 20 m / min.

6. The device according to claim 1, wherein The bracket is installed 15 cm vertically above the midpoint of the length direction of the conveyor belt.

7. The device according to claim 1, characterized in that The nozzle group is composed of at least 5 mist nozzles connected together, and each nozzle is designed with an independent control switch.

8. A method for simulating the spraying of heat stabilizer on cellulose insulation paper, characterized in that: The method comprises the following steps: S1. Prepare thermal stabilizer solution; S2. Adjust the height and horizontal angle of the conveyor belt; S3. Rotate the central axis of the mist nozzle group to adjust the nozzle-paper angle, and turn on the mist nozzle switch combination according to the experimental needs; S4, allowing hot water and the heat stabilizer solution to enter the pipeline for rinsing respectively; S5, cutting the insulating paper into paper sheets of uniform width and winding them on the surface of the conveyor belt; S6. Mark the position where the nozzle direction intersects the paper web, start the conveyor belt, adjust the speed, and turn on the water pump to spray, so that the heat stabilizer solution is sprayed on the paper web; S7. Turn off all switches and remove the insulation paper sample from the conveyor belt surface.

9. The method according to claim 8, characterized in that The heat stabilizer solution is a nitrogen-containing heat stabilizer solution.

10. The method according to claim 8, characterized in that No adhesive should be used between the paper web and the conveyor belt.

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