Capacitive divider vacuum drying oven and method

Abstract

This invention relates to a vacuum drying oven and method for capacitor voltage dividers, comprising a drying chamber, with a gas filling chamber and a heating chamber arranged sequentially from top to bottom at the lower end of the drying chamber. The gas filling chamber is connected to a heating gas pipeline, and the heating chamber is connected to a high-temperature oil injection pipeline. Multiple vent holes at the lower end of the drying chamber communicate with the gas filling chamber. Additionally, a cavity is provided within the drying chamber wall, communicating with the gas filling chamber. An exhaust pipeline and a vacuum pipeline are provided on the drying chamber. Control valves for controlling the on / off state of the heating gas pipeline, high-temperature oil injection pipeline, exhaust pipeline, and vacuum pipeline are all provided on the pipelines. A core assembly frame is located inside the drying chamber, and the core assembly frame has multiple layers of support frames along its height. During drying, capacitor core assemblies are placed on the corresponding layers of support frames, with capacitor core assemblies on adjacent support frames placed vertically. This invention significantly improves the drying efficiency of capacitor core assemblies, and is particularly suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of capacitive voltage divider manufacturing, specifically a vacuum drying oven and method for capacitive voltage dividers. Background Technology

[0002] In the existing technology, there are two main methods for drying and oiling capacitive voltage dividers: one method is to assemble the core assembly of the capacitive voltage divider into a whole, stack it in an oil filling tank, and then put it into a vacuum drying tank for drying and impregnation. After that, it is taken out from the oil tank and installed into a hollow insulator, then vacuum impregnated again. After assembly, it is put into a vacuum drying tank for drying and leak testing. This method requires the completion of related processes in conjunction with the oil tank, which not only takes a relatively long time, but also cannot avoid the loss of impregnating agent (oil) and environmental pollution during the process of taking the core assembly out of the oil tank.

[0003] Another existing method involves assembling the capacitor divider core assembly into a single unit, inserting it into a hollow insulator, and then placing the entire assembly into a vacuum drying chamber for vacuum drying and vacuum oil filling. Because the core assembly is inside the hollow insulator, this method significantly increases its size. For example, a typical TYD110 / √3-0.01H capacitor core assembly is 125×175×900mm, but after being inserted into the hollow insulator, its size is φ390×1315mm. Furthermore, it cannot be stacked, taking up considerable space. Additionally, the heat insulation of the hollow insulator negatively impacts the drying effect. Moreover, the vertical placement of the core assembly results in a longer moisture removal path within the component, leading to a relatively longer processing time.

[0004] Patent CN102253263B discloses a single-extraction, single-injection vacuum treatment device and method for a capacitor voltage divider. It has two parallel distribution pipes on the vacuum tank, one of which is connected to the main oil injection pipe and the other is connected to the main vacuum extraction pipe. In this way, the device can complete the drying, degassing, and oil impregnation of the capacitor voltage divider in the vacuum tank in one step after assembly. However, this device is the same as the second type mentioned above where the capacitor voltage divider is assembled and placed in the vacuum drying tank as a whole. In addition to occupying space, the process time is relatively long.

[0005] CN115523722B patent discloses a special oil-heated vacuum drying oven for capacitors, which includes an outer shell and an inner drying chamber inside the outer shell. The top of the inner drying chamber is equipped with a vacuum state detection component and a drying degree detection component to indicate the degree of simulated vacuum inside the inner drying chamber. However, the purpose of this device is to effectively determine whether water vapor is continuously generated inside the inner drying chamber during the drying process by observing the flame color in the combustion chamber at the end of the drying degree detection component, thereby effectively controlling the degree of drying completion. However, the number of capacitors dried at one time by this device is very small, so this device is more suitable for experimental observation and cannot meet the needs of actual production. Summary of the Invention

[0006] The purpose of this invention is to provide a vacuum drying oven and method for a capacitor voltage divider, wherein the entire bottom of the vacuum drying oven is circulated with heated inert gas for drying, and the capacitor core assembly is arranged in multiple layers and placed horizontally in the vacuum drying oven, thereby improving the drying efficiency of the capacitor core assembly, which is especially suitable for mass production.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A vacuum drying chamber for a capacitor voltage divider includes a drying chamber body, with an inflation chamber and a heating chamber arranged sequentially from top to bottom at the lower end of the drying chamber body. The inflation chamber is connected to a heating gas pipeline, and the heating chamber is connected to a high-temperature oil injection pipeline. The lower end of the drying chamber body has multiple vent holes communicating with the inflation chamber. Additionally, the chamber wall of the drying chamber body has a cavity communicating with the inflation chamber. The drying chamber body is equipped with an exhaust pipeline and a vacuum pipeline. Each of the heating gas pipeline, high-temperature oil injection pipeline, exhaust pipeline, and vacuum pipeline is equipped with a control valve to control the on / off state of the pipeline. The drying chamber body contains a core assembly frame, and the core assembly frame has multiple layers of support frames along the height direction. During drying, the capacitor core assemblies are placed on the support frames of the corresponding layers, and the capacitor core assemblies on adjacent support frames are placed vertically.

[0009] The core assembly frame is provided with multiple upright beams, and each layer of support frame is fixed by the corresponding upright beams. The capacitor core assembly is inserted into the space between the upright beams.

[0010] The drying chamber is equipped with a vacuum sensor and a temperature sensor.

[0011] A method for using a vacuum drying oven based on the aforementioned capacitive voltage divider includes the following steps:

[0012] Step 1: Start the heating gas pipeline to inject gas into the inflation chamber, and after the gas is injected into the drying chamber, the air inside the drying chamber will be expelled from bottom to top;

[0013] Step 2: Start the high-temperature oil injection pipeline to inject high-temperature oil into the heating chamber, so that the heating chamber starts to heat the gas in the filling chamber, thereby making the temperature inside the drying chamber meet the requirements;

[0014] Step 3: Start the vacuum line to achieve multiple pressure cycles of vacuum level changes inside the drying chamber;

[0015] Step 4: After the transformer cycle has been performed a set number of times, the vacuum line is increased to achieve high vacuum drying of the capacitor core assembly inside the drying chamber.

[0016] Step 5: After the high vacuum drying of the capacitor core assembly reaches the set time, the high temperature oil injection pipeline is cooled down to the set temperature through the oil heating device, thereby cooling the drying chamber to the set temperature.

[0017] The advantages and positive effects of this invention are as follows:

[0018] 1. This invention allows the entire bottom of the vacuum drying oven to be circulated with heated inert gas for drying, and the oven wall has cavities filled with inert gas for auxiliary heating. This not only ensures the heating and drying efficiency, but also makes the heating of each part of the oven more uniform, thus ensuring the drying effect.

[0019] 2. The present invention has a core assembly frame including multiple support frames inside the vacuum drying oven. The capacitor core assembly is placed horizontally on the corresponding support frame, and the capacitor core assemblies on adjacent support frames are axially perpendicular. This allows multiple capacitor core assemblies to be dried at one time. At the same time, compared with the prior art, the water vapor discharge path of the present invention is also greatly shortened, thereby further improving the drying efficiency. It is especially suitable for actual mass production of products.

[0020] 3. In the drying process, the present invention utilizes a vacuum pipeline to control the circulating pressure change within the vacuum drying chamber to create gas convection within the chamber, thereby further improving heating efficiency and heating uniformity. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the vacuum drying oven structure used in this invention.

[0022] Figure 2 This is a schematic diagram illustrating the process of drying a capacitor voltage divider entirely in a vacuum drying chamber, as described in existing technologies.

[0023] Figure 3 This is a schematic diagram of the oil injection state of the present invention.

[0024] Among them, 1 is the drying chamber, 101 is the air filling chamber, 102 is the heating chamber, 103 is the chamber wall cavity, 104 is the vent hole, 2 is the core assembly frame, 201 is the support frame, 202 is the upright beam, 3 is the capacitor core assembly, 4 is the hollow insulator, and 5 is the oil injection pipe. Detailed Implementation

[0025] The invention will now be described in further detail with reference to the accompanying drawings.

[0026] like Figure 1As shown, the present invention includes a drying chamber 1, and the lower end of the drying chamber 1 is provided with an inflation chamber 101 and a heating chamber 102 from top to bottom. The inflation chamber 101 is connected to a heating gas pipeline, and the heating chamber 102 is connected to a high-temperature oil injection pipeline. The lower end of the drying chamber 1 has multiple vent holes 104 communicating with the inflation chamber 101. Additionally, the drying chamber 1 has a cavity 103 within its wall communicating with the inflation chamber 101. The drying chamber 1 is provided with an exhaust pipeline and a vacuum pipeline, and each of the heating gas pipeline, high-temperature oil injection pipeline, exhaust pipeline, and vacuum pipeline is equipped with a control device for controlling the on / off state of the pipeline. The drying chamber 1 is equipped with a core assembly frame 2, and the core assembly frame 2 has multiple support frames 201 along the height direction. During drying, the capacitor core assembly 3 is placed on the support frame 201 of the corresponding layer, and the capacitor core assembly 3 on the adjacent support frame 201 is placed vertically. The core assembly frame 2 is equipped with multiple upright beams 202, and each layer of support frame 201 is fixed by the corresponding upright beams 202. The capacitor core assembly 3 can be inserted or removed through the space between the upright beams 202. The drying chamber 1 is equipped with a vacuum sensor and a temperature sensor for real-time detection of the vacuum degree and temperature inside the chamber. The vacuum sensor and temperature sensor are commercially available products.

[0027] This invention is based on Figure 2 Analyzing the existing technology, when the capacitor core group 3 and hollow insulator 4 of the capacitor divider are assembled and placed in a vacuum drying tank for vacuum drying, and oil is directly injected into the tank under vacuum, although each process can be completed at once, the hollow insulator 4 is large in size and can only be placed vertically and cannot be stacked, which takes up a lot of space. Moreover, the heat insulation of the hollow insulator affects the drying effect. In addition, the vertical setting of the capacitor core group 3 creates a water vapor discharge path, which leads to a longer drying time in the entire process, thus prolonging the overall process time.

[0028] And such Figure 1 As shown, this invention is designed for the drying section. After assembly, the capacitor core assembly 3 is not initially placed into the hollow insulator 4, but rather horizontally stacked in multiple layers on the support frames 201 of the core assembly frame 2 within the drying chamber 1. During drying, the inflation chamber 101 is filled with inert gas, and the high-temperature oil injected into the heating chamber 102 heats the inflation chamber 101. The heated inert gas then enters the drying chamber 1 from bottom to top. Compared to existing technologies (such as patent CN115523722B), which only utilize pipelines to inject inert gas for heating, this invention injects inert gas into the entire bottom of the drying chamber 1 for heating. This not only improves the heating and drying efficiency but also ensures more uniform heating because inert gas is present in all parts of the chamber. Furthermore, this invention includes a chamber wall cavity 103 filled with heating inert gas within the chamber wall of the drying chamber 1, allowing heating from the surrounding side walls into the chamber, further guaranteeing heating and drying efficiency and heating uniformity. Figure 1 As shown, the heated water and gas are discharged upwards and eventually discharged through the exhaust pipe at the top of the drying chamber 1. Furthermore, since each capacitor core group 3 is placed horizontally, the water and gas discharge path of the present invention is greatly shortened.

[0029] This invention not only improves drying efficiency, but also allows for the simultaneous drying of multiple capacitor core groups 3, resulting in the following: Figure 3 The dried capacitor core assembly 3 is then installed into the hollow insulator 4 and subjected to external vacuum oil injection and leak testing via the oil injection pipe 5. This is a well-known technique in the field; for example, see patent CN102253263B. However, taking the TYD110 / √3-0.01H capacitor core assembly as an example, the processing time using the patent CN102253263B process would take 7 days. This invention, due to its significantly shortened drying process, can control the processing time to within 5.5 days.

[0030] The drying method of the present invention includes the following steps:

[0031] Step 1: Exhausting gas. At this time, the heating gas pipeline is activated to inject gas into the inflation chamber 101. The gas is an inert gas. Since the molecular weight of the inert gas is greater than that of air, after being injected into the chamber, it will expel the air in the drying chamber 1 from bottom to top.

[0032] Step Two: Preheating. The high-temperature oil injection pipeline is connected to an oil heating device. The oil heating device is activated, and high-temperature oil is injected into the heating chamber 102 through the high-temperature oil injection pipeline. The heating chamber 102 heats the gas in the inflation chamber 101, thereby ensuring the temperature inside the drying chamber 1 meets the requirements. The oil heating device is a well-known technology in the art; for example, see patent CN115523722B.

[0033] Step 3: The vacuum pipeline on the drying chamber 1 realizes the pressure change circulation of the vacuum degree inside the chamber. This can make full use of the convection of the gas inside the chamber and the conduction of radiation from the chamber wall during the heating process, so as to improve the heating efficiency and ensure uniform heating, avoiding the disadvantage that the convection of the gas inside the chamber cannot be achieved by a single vacuuming.

[0034] Step 4: Increase the vacuum level of the vacuum line on the drying chamber 1 to achieve high vacuum drying of the capacitor core assembly 3 inside the chamber.

[0035] Step 5: The high-temperature oil injection pipeline is cooled down to the set temperature by the oil heating device, thereby cooling the drying chamber 1 to the set temperature.

[0036] In one application example of the present invention, the control parameters for the above steps are shown in the table below:

Claims

1. A capacitor voltage divider vacuum drying oven, characterized in that: The equipment includes a drying chamber (1), and the lower end of the drying chamber (1) is provided with an air filling chamber (101) and a heating chamber (102) from top to bottom. The air filling chamber (101) is connected to a heating gas pipeline, and the heating chamber (102) is connected to a high-temperature oil injection pipeline. The lower end of the drying chamber (1) has multiple vent holes (104) communicating with the air filling chamber (101). Additionally, the drying chamber (1) has a cavity (103) in its wall communicating with the air filling chamber (101). The drying chamber (1) is provided with an exhaust pipe and a vacuum pipe, and the heating gas pipe, high temperature oil injection pipe, exhaust pipe and vacuum pipe are all provided with control valves to control the opening and closing of the pipes. The drying chamber (1) is provided with a core assembly frame (2), and the core assembly frame (2) is provided with multiple support frames (201) along the height direction. During drying, the capacitor core assembly (3) is placed on the support frame (201) of the corresponding layer, and the capacitor core assembly (3) on the adjacent support frames (201) is placed vertically.

2. The capacitor voltage divider vacuum drying oven according to claim 1, characterized in that: The core assembly frame (2) is provided with multiple upright beams (202), and each layer of support frame (201) is fixed by the corresponding upright beam (202). The capacitor core assembly (3) is inserted into the space between the upright beams (202).

3. The capacitor voltage divider vacuum drying oven according to claim 1, characterized in that: The drying chamber (1) is equipped with a vacuum sensor and a temperature sensor.

4. A method for a vacuum drying oven for a capacitor voltage divider according to claim 1, characterized in that: Includes the following steps: Step 1: Start the heating gas pipeline to inject gas into the filling chamber (101), and after the gas is injected into the drying chamber (1), the air in the drying chamber (1) is discharged from bottom to top; Step 2: The high-temperature oil injection pipeline is started to inject high-temperature oil into the heating chamber (102) so that the heating chamber (102) starts to heat the gas in the gas filling chamber (101), thereby making the temperature in the drying box (1) meet the requirements; Step 3: Start the vacuum line to achieve multiple pressure cycles of vacuum level change in the drying chamber (1); Step 4: After the transformer cycle is performed a set number of times, the vacuum line is increased to achieve high vacuum drying of the capacitor core assembly (3) inside the drying chamber (1); Step 5: After the high vacuum drying of the capacitor core assembly (3) reaches the set time, the high temperature oil injection pipeline is cooled down to the set temperature through the oil heating device, thereby cooling the drying chamber (1) to the set temperature.

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