JPH0532884B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method and a decontamination device for simply and economically decontaminating recycled oil containing impurities in order to reuse a transformer using recycled oil. [Prior art] Impurities whose use is regulated by the government (for example, polychlorinated biphenyl, commonly known as PCB) have been detected in the insulating oil of pole transformers that use recycled oil.
I am currently struggling with how to deal with this. Since the impurities have excellent flame retardancy as well as electrical insulation properties, they are widely used in various industrial fields, and insulating oil for transformers is no exception. However, today, its use is regulated as a substance that has an adverse effect on the human body. However, for example, when a pole-mounted transformer reaches the end of its lifespan or malfunctions, a new transformer is mounted on the pole and used.On the other hand, transformers that come down from the pole due to their lifespan are dismantled and scrapped. However, the insulating oil is extracted from the transformer before disassembly.
This is often subjected to various recycling treatments and used again as insulating oil (hereinafter referred to as recycled oil).
However, among the insulating oils subjected to the above-mentioned regeneration treatment,
Many of the impurities whose use is regulated are contained in the insulating oil that was used before the use of the impurities was regulated. For some reason, the residual content was sometimes mistakenly used as recycled oil. in this case,
Although the pole transformer lubricated with the recycled oil does not have any particular problems when using the transformer itself, it is not recommended to use recycled oil because it contains impurities whose use is regulated. It was difficult to use the existing pole-mounted transformer as is due to conventional social conventions. [Problem to be Solved by the Invention] However, in a pole transformer using the recycled oil as an insulating oil, it is difficult to determine which pole transformer the recycled oil lubricated contains impurities exceeding the regulation value. It has been practically difficult to extract the recycled oil from each transformed transformer and measure and analyze it, as it requires a great deal of time and effort. For this reason, either all pole transformers that use recycled oil are collected, the recycled oil is deoiled from these transformers, and then new oil (insulating oil) is filled in for reuse. Or, it was necessary to dispose of it. However, in the former case, when the recycled oil is replaced with new oil and the concentration is measured, for example, the impurity concentration is approximately
The recycled oil, which had measured 50ppm (below the general detection limit of 0.5ppm), was removed from the transformer and immediately after replacing it with new oil, the concentration was measured and found to be 0.48ppm. However, when the concentration was measured again one week later under the above conditions, it was 2.02 ppm, and when the concentration of the recycled oil was measured 30 days after electricity was applied in this condition, it was 2.38 ppm. From the above measurement results, even if you simply remove the recycled oil and replace it with new oil,
This is thought to be the result of residual oil impregnated into the new oil, which is impregnated between the layers of insulating materials such as wire sheathing paper and interlayer insulating paper, and the core, which make up the main parts of the transformer body. Furthermore, it is estimated that it takes 20 to 30 days for the impurity concentration to reach an equilibrium state after replacing the new oil. Therefore, when we took out the new oil again, filled it with new insulating oil, and measured the remaining impurity content, it was less than 0.10 ppm immediately after the oil was filled again, and the measurement one week later showed the same measurement value. It was hot. When electricity was further applied and measurements were taken again one week later, it was found to be 0.11 ppm, which was below the general detection limit. From the above measurement results, it has been found that replacing the fresh oil two to three times can diffuse impurities and reduce their concentration to a degree of dilution close to undetectable. However, replacing new oil multiple times in order to dilute the residual impurity content of the recycled oil to below the regulatory value takes a lot of time and money, considering the number of transformers using recycled oil. In addition, replacing the new oil many times requires processing the recycled oil and also processing the new oil that has been replaced but has been extracted again, and the processing cost is enormous. In addition to causing problems, there was a risk of inducing new secondary pollution in the processing of recycled oil. In addition, the latter does not seem to cause any particular problems if only a small number of transformers are to be disposed of, but considering the number of transformers that use recycled oil, there is a limit to where they can be disposed of, and the cost of dismantling them is also taken into consideration. Therefore, it is not possible to adopt it physically and economically. In view of the various problems mentioned above, the present invention subjects the transformer from which the recycled oil has been removed to vacuum heating and drying for a certain period of time while taking into account a specific temperature and degree of vacuum, so that the recycled oil remains inside the transformer body. The purpose of the present invention is to provide a simple decontamination method and decontamination device for recycled oil that removes impurities to a state that is nearly undetectable, and then lubricates with new oil, making it possible to reuse a transformer using recycled oil. . [Means for Solving the Problems] The present invention uses a pump or the like to extract recycled oil from inside a transformer, then rotates the transformer 180° using an inversion device, and collects the oil on the bottom of the transformer case. Remove the oil by dripping and draining any recycled oil that is present or adhering to the transformer body. After the recycled oil has been drained for a certain period of time, the transformer is transported upside down to a vacuum heating dryer and heated for several hours at a temperature that allows the transformer's insulating material to be reused without being affected by heat. Drying treatment is performed, followed by vacuum drying treatment at the above temperature and predetermined degree of vacuum for several tens of hours, and the atmospheric gas inside the vacuum heating drying device containing oil and moisture generated during the heating drying process is forcibly discharged. (absorbing treatment without dispersing it into the atmosphere outside the equipment) to promote heating and drying of the transformer body,
Impurities are forcibly evaporated together with the remaining recycled oil, and the atmospheric gas is forcibly exhausted. As described above, the recycled oil remaining in the transformer case and the recycled oil and impurities impregnated or attached to the transformer body are evaporated and removed. After vacuum heating and drying the transformer body, new insulating oil is applied at a predetermined degree of vacuum to remove impurities to the point where they are almost undetectable, making it possible to reuse transformers using recycled oil. It is characterized by what it did. [Operation] By reprocessing a transformer using recycled oil as described above, the present invention makes it possible to reuse this type of transformer with almost no remaining impurities. At the same time, it is also possible to automate most of the work processes for reprocessing, such as the process of extracting recycled oil, the process of overturning the transformer to drain the oil, and the vacuum heating drying process while the transformer remains overturned. Therefore, decontamination of transformers using recycled oil can be carried out continuously, safely, economically, and smoothly without requiring too much manpower, and without taking too much work time. . [Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 9. Fig. 1 is a process diagram showing the reprocessing process for a transformer using recycled oil, and Fig. 2 is a process diagram showing the process of removing the recycled oil for the reprocessing and decontaminating the transformer using recycled oil so that it can be reused. 1 is a block diagram showing a schematic system configuration of a decontamination apparatus for decontamination. Based on FIGS. 1 and 2, an outline of decontamination processing for a transformer using recycled oil (see FIG. 9) will be explained. In FIG. 2, reference numeral 1 indicates a mounting location of a transformer using recycled oil. For example, a required number of transformers using recycled oil 50 (hereinafter simply referred to as transformers) shown in FIG. 9 are arranged side by side, and in this state, The cover 52 of the transformer 50 is removed from the case 51, and the recycled oil in the case 51 is sequentially drawn out using a pump (not shown). The extracted recycled oil will be stored in drums, etc. 2, the transformer 50 from which the recycled oil has been removed is rotated by 180 degrees to form the case 51.
A turning device (see FIGS. 3 to 6, details will be described later) that changes the opening 53 of the case 51 downward.
The transformer is rotated in order to drain the recycled oil that has accumulated inside the transformer. 3 indicates an oil-draining storage area where the transformer 50 rotated by the rotation device 2 is stored for a certain period of time in a rotated state, for example, it is formed by installing a roller conveyor, and the transformer 50 is rotated The transformer is left as it is for about 10 to 15 hours, and the recycled oil remaining in the case 51 and the recycled oil adhering to the transformer body 54 are dripped to drain the oil. Reference numeral 4 denotes a movable trolley for the transformer 50, and while the transformer 50a, which has been discharged and drained for a certain period of time, is still rotated, the movable trolley 4 is moved by a hoisting and moving means 5 such as a crane, for example. will be installed in sequence. Reference numeral 6 denotes a vacuum heating device, in which the rotated transformer 50a is carried into the device 6 while being placed on the trolley 4, and the atmospheric temperature in the vacuum heating device 6 is raised to about 110°C.
After heating and drying the transformer 50a for several hours at a temperature of 51 and impregnated or attached to the transformer body 54, and vacuum heating drying device 6
By forcibly discharging and collecting the atmospheric gas containing oil and moisture floating inside, the recycled oil adhering to the inside and outside of the case 51 and the transformer body 54 is freed from impurities. The transformer 50a is subjected to a vacuum/heat drying process so that it can be evaporated to an undetectable level (see FIG. 6, details will be described later). Reference numeral 8 denotes a transformer 50a that has been subjected to the necessary vacuum and heat treatment in the vacuum heating and drying device 6.
This is a movable cart that is pulled out from the container and transported to the next process, and the cart 4 is also used as it is. Also, this moving trolley 8
A lifting means 9 such as a crane is installed on the top, and the moving trolley 8 is installed with the opening 53 facing downward.
The transformer 50a mounted on the transformer 50a is lifted up and placed on a roller conveyor (not shown) provided close to the turning device 10 (same structure as the turning device 2). The turning device 10 described above turns the transformer 50a, whose opening 53 faces downward, by 180 degrees to return it to its normal state. After this, the transformer 50a is transferred to the turning device 10.
, and transported to the temporary storage location 11 using a roller conveyor. The transformer 50a, which has cooled down to a predetermined temperature at the temporary storage location, is transferred to the vacuum lubrication device 12.
(See Figure 8, details will be described later).
Fill the case 51 with new insulating oil in a near-vacuum state. Opening 53 of case 51 after filling with new oil
A cover 52 is placed on the cover 52, and in this state, an electrical property test is conducted, and those that pass are stored at the shipping location 13 until the time of shipping. By completing the above-mentioned work steps, the decontamination process for the transformer 50 using recycled oil is completed, and its reuse is planned. In FIG. 2, 14 represents a vacuum pump, and 15 represents an oil tank for storing new insulating oil. Next, the configuration of the main equipment of the apparatus for decontaminating the transformer 50 using recycled oil will be explained with reference to FIGS. 3 to 8. First, the configuration of the turning devices 2 and 10 for turning and raising the transformer 50 will be explained with reference to FIGS. 3 and 6. The turning device 2 connects the two turning wheels 16, 16a with a horizontal beam 17, while maintaining an interval that allows the transformer 50 to pass through.
A ring-shaped rotating body 18 is formed by fixing the upper and lower parts with 17a, and a sliding body 19 having a required number of rollers arranged in parallel is attached to the upper side of this rotating body, and the upper part of the rotating body 18 is attached to the lower part. Slide body 19 fixed on the side
Correspondingly, the cylinder 21 on which the sliding body 20 is placed and fixed so as to be movable up and down is fitted onto the lower cross beam 17a.
As shown in FIG. 3, the rotating body 18 is
It is rotatably mounted on a rotating roller 24 rotatably mounted on the base 22 via a bearing plate 23, and includes an electric motor 25 with a reduction gear and one of the roller shafts 26 having rotating rollers 24, 24 at both ends. The motor 25 is driven and connected by a belt or the like, and the rotating roller 2 is activated.
4 and 24, the rotating body 18 also
It is configured to rotate with sliding bodies 19 and 20 provided at the lower part. 27, 27a are rotating bodies 1
The sliding bodies 19 and 20 provided on the rotating body 18 move the roller conveyor 2 forward and backward every time the rotating body 18 rotates by 180 degrees.
7 and 27a so as to be at the same height. Further, 28 indicates a discharge chute for recycled oil. Note that the turning device 10 for pulling the drying-processed transformer 50a pulled out from the vacuum heating drying device 6 to its original state, that is, toward the upper side of the opening 53, is of the same structure as the turning device 2, and therefore will not be described. is omitted. Next, the configuration of the vacuum heating drying device 6 will be explained with reference to FIG. 7. The vacuum heating drying device 6 includes a vacuum heating furnace 30, electric doors 31, 31a that open and close the inlet and outlet sides of the heating furnace 30, and heating wires or hot water connected to the inner wall surface and bottom surface of the vacuum heating furnace 30. It is equipped with a heating body 32 formed by arranging pipes, etc., and a stirring fan 33 for stirring the atmospheric gas in the vacuum heating furnace 30. Furthermore, a vacuum pump 7 is installed outside, and this vacuum pump 7
and the vacuum heating furnace 30 are connected by piping with an exhaust pipe 35 via a water-cooled condenser 34 and an electromagnetic valve _S1 . Also, in Figure 7, 36
37 is a soot trap installed in the vacuum pump 7, and 37 is a water pipe that supplies cooling water to the water-cooled condenser 34.
Electromagnetic valves S ₂ and S ₃ for opening and closing the water pipe 37 are installed on the water passage side and the drainage side, respectively.
38 is a drain that stores liquefied oil and water cooled by the water-cooled condenser 34, and a solenoid valve S ₄
It is attached to the water-cooled condenser 34 via. Furthermore,
S ₅ is an electromagnetic valve attached to the vacuum heating furnace 30 side to return the vacuum state in the vacuum heating furnace 30 to normal pressure, 39 is a lighting lamp that illuminates the inside of the furnace, and 40 is the heating furnace 3
0 viewing window. Next, the configuration of the vacuum lubrication device 12 will be explained. In FIG. 8, reference numeral 41 denotes a temporary cover for covering the opening 53 of the transformer 50a, which is used when the inside of the case 51 of the transformer 50a, which has been vacuum heated and dried to remove oil, is brought into a vacuum state again; This temporary lid 4
A pipe 42 connected to the vacuum pump 14 and a pipe 43 connected to the oil tank 15 are connected to the case 5 through electromagnetic valves S ₆ and S ₇ in the middle of the piping, respectively.
1 and is configured by being connected for communication with the inside of 1. The vacuum heating and drying device 6 and the vacuum lubricating device 12 described above are driven and controlled in accordance with a preset sequence by command signals from a control device (not shown). Next, the decontamination process for the transformer 50 using recycled oil will be explained. First, at the installation location 1 of the transformer 50,
The cover 52 of the transformer 50 is removed, and the recycled oil is extracted from inside the case 51 using a pump (not shown) or the like. Next, the transformer 50 from which the recycled oil has been drained is placed on the pallet 29 with its opening 53 covered with a grid-like pallet 29a, as shown in FIG.
It is moved on the roller conveyor 27 and carried onto the sliding body 20 provided on the rotating body 18 of the turning device 2. In this state, the turning device 2 is operated by operating an operation switch provided on the operation panel of the control device (not shown) to drive the cylinder 21, and the transformer 50 is moved so that the pallet 29a is connected to the upper sliding body 19 as shown in FIG. Move it up until it makes contact. After that, the electric motor 25 is started and the rotating body 1 mounted on the rotating rollers 24, 24
8 by 180 degrees as shown in Figure 5, and transformer 5.
0 so that the opening 53 faces downward. In this state, the cylinder 21 is returned to its original position, and then the transformed transformer 50 is moved from the sliding body 19 to the oil drain storage area 3 via the roller conveyor 27a, where it remains in the case 51. Drain the oil while dripping the recycled oil. Note that the dropped oil flows down to the discharge chute 28 and is safely collected in a drum can or the like (not shown). The time required to drain the oil from the inverted transformer 50 is about 10 to 15 hours. This means that the recycled oil remaining in the case 51 drips in a relatively short time (1 to 2 hours). However, 80 to 90% of the oil remaining in the transformer body 54 is impregnated and attached to the coil, and the remaining 10 to 20% is attached to the iron core and other parts. It is thought that there are. For this reason, when the inventors of the present invention conducted a drip discharge test of the amount of remaining oil using an actual device, it was observed that the oil dripped relatively smoothly for 10 hours from the time when Case 51 was turned over. It was found that after 10 hours, only a small amount was dripped. This is believed to be because most of the remaining oil is dripped and discharged during the 10 hours that have passed since the transformer 50 was reversed. However, if the transformer 50 is left in the inverted state for a longer period of time (48 to 72 hours), the amount of dripping will increase slightly, but this is not considered a good idea as it will take too much time to drain the oil. Therefore, as a result of the above-mentioned test, it was found that 10 to 15 hours is appropriate for decontaminating the transformer 50, considering the post-process, and even if more time is spent unnecessarily, the oil removal effect will not be effective. It turned out that very little was obtained. The transformer 50a, which has been drained of the recycled oil as described above, is placed on the moving trolley 4 from the oil draining storage area 3 by the hoisting and moving means 5, and is kept in an airtight state for the next decontamination process. It is carried into the vacuum heating drying device 6. The device 6 is driven and controlled by a command signal from a control device (not shown), and the transformer 50
When the electric door 31, 31a is brought in together with the movable trolley 4 while being inverted, the heating element 32 is immediately activated to raise the atmospheric temperature in the vacuum heating furnace 30 to the set temperature. At this time, the transformer body 5
The ratio of the amount of oil remaining in 4 is, as mentioned above,
Approximately 80-90% of it is attached to the inside of the coil, and 10-20% is attached to the iron core and other parts. Therefore, whether or not the transformer 50a can be reused depends on how much of these residual oils can be removed. For this reason, the present inventors conducted various tests to determine how quickly and efficiently the residual oil could be removed. If the transformer main body 54 is first heated and dried while being housed in the case 51 with the opening 53 of the case 51 facing upward, the remaining oil impregnated in the constituent material of the transformer main body 54 will be heated. As a result, the viscosity decreases, and it falls to the bottom of the case 51 and accumulates therein. Next, a test was conducted with the opening 53 of the case 51 facing downward. In this case, the remaining oil naturally falls out of the case 51 as the viscosity of the remaining oil decreases. As a result of the above test, when discharging the residual oil whose viscosity has been reduced by heating and drying, it is better to drain it outside the case 51 with the opening 53 of the case 51 facing downward, rather than dropping it into the case 51 and letting it evaporate. Since it was found that the evaporation efficiency of the residual oil was clearly better when the oil was discharged dropwise, in the present invention, as described above, in the present invention, the case 51 was carried into the vacuum heating dryer 6 while being inverted. Next, the transformer body 5
4 housed in the case 51 and the transformer body 5
4 was removed from the case 51 and the evaporation efficiency of residual oil was measured in the state of the main body alone, and it was found that there was no significant difference in the residual oil reduction effect in either method. Therefore, in the present invention, the transformer body 54 is heated and dried while being housed in the case 51 in consideration of work efficiency. Next, when setting the heating and drying temperature, a test was conducted to verify the deterioration of the insulating material used in the transformer body 54. Wire-coated paper, kraft paper, or adhesive insulating paper was selected as the insulating material, left at a heating temperature of 110℃ for 0 to 8 days, and tested according to JIS C2111 (electrical insulation testing method) with the tensile strength on the first day set as 100. The results are shown in Table 1.

[Table] The numerical values in the table are the average values of 5 measurements. As is clear from this table, the three types of samples are
No decrease in tensile strength was observed even after continuous heating at 110°C for 8 days. Therefore, the transformer body 54
It was found that when heat-dried at a temperature of 110°C, there was no deterioration or damage to the insulating material due to thermal effects, and it was found that it could be reused. Subsequently, when the remaining oil was evaporated by heating and drying, a test was conducted to see if impurities were evaporated. Generally, the boiling point of insulating oil is 270 to 350℃, and the boiling point of impurities conventionally used in transformers is
The temperature was 210 to 390°C, and since the two had a very close temperature relationship, the amount of evaporation of both was confirmed. The test consisted of air drying conducted at temperatures of 100℃ and 110℃ for 61 hours, and vacuum heating drying (heating temperature 110℃, degree of vacuum).
Table 2 shows the results obtained under the conditions (0.05 Torr, 46 hours).

[Table] As is clear from Table 2, it was found that impurities also evaporated at the same time as the residual oil (regenerated oil) evaporated. In Table 2, if only the air drying treatment is performed, the evaporated impurities will be directly diffused into the atmosphere, leading to air pollution. Therefore, in the present invention, as shown in FIG. Atmospheric gas containing oil and moisture from residual oil that has evaporated and accumulated in the vacuum pump 7 is sucked (vacuum degree
0.05 Torr), and the atmospheric gas (oil mist) is cooled and condensed by a water-cooled condenser 34 on the way.
The liquefied oil and moisture are collected in the drain 38, and the gas is absorbed in the oil smoke trap 36 to absorb impurities.
It is configured to diffuse into the atmosphere as a clean gas. Therefore, there is no possibility that atmospheric gas containing impurities will be discharged from inside the vacuum heating furnace 30 to the outside and cause air pollution. Incidentally, the driving start timing and driving time of the vacuum pump 7, and the corresponding electromagnetic valves _S1 to _S4 are all sequentially controlled by command signals from the control device. Next, when the remaining oil is evaporated, a test was conducted to determine the extent to which impurities are adsorbed to the insulating material, that is, whether or not they are adsorbed. The test conditions were as follows: 200 g of insulating paper was placed in a test container containing 1.2 insulating oil containing impurities, and after being left at a temperature of 20°C for 16 days,
It was left for an additional 2 days at a temperature of 80°C. Then, the impurities in the insulating oil were analyzed for each number of days of storage, and the results are shown in Table 3. Note that the impurity concentrations in Table 3 were calculated with the concentration on the first day as 100.

[Table] As is clear from Table 3, there is almost no change in the concentration of impurities in the insulating oil. This means that
It can be judged that impurities are not particularly easily adsorbed to insulating paper. As a result, it seems reasonable to assume that impurities are uniformly distributed in the insulating oil. Therefore, by forcibly removing the remaining amount of recycled oil impregnated and attached to the transformer body 54 of the transformer 50a that has been drained, based on the heating temperature and degree of vacuum described above, the recycled oil is The impurities contained in
It has been found that it is possible to remove the oil by evaporation together with the recycled oil. Regarding the effect of diluting impurities in the case where the transformer 50a after oil removal is subjected to the decontamination treatment of recycled oil by vacuum heating drying according to the present invention and the case where the decontamination treatment is performed only at room temperature and hot air. Measurements were carried out and the results are shown in Table 4.

〔Effect of the invention〕

Since the present invention is configured as described above, it has the following effects. (1) The present invention can automate the decontamination process of recycled oil in transformers using recycled oil with almost no human effort, so the decontamination work of recycled oil can be carried out safely and efficiently. be able to. (2) Especially when draining and drying recycled oil,
By adopting a rotating device, the transformer is installed with its opening facing downward, allowing the decontamination of recycled oil to be carried out while allowing residual oil to fall naturally. It is extremely easy to remove residual oil that has impregnated and adhered to the surface. (3) In addition, impurities contained in recycled oil that are subject to usage regulations are difficult to adsorb to insulating materials, so together with the recycled oil, heating temperature within a specific range and evaporated substances are forcibly exhausted. Since it is possible to quickly and reliably eliminate transformers using recycled oil in combination with other means, it is possible to reprocess transformers using recycled oil without fail, and to prevent the reuse of such transformers from causing secondary pollution. It is very convenient and can be used economically.

[Brief explanation of the drawing]

Fig. 1 is a schematic process diagram for implementing the decontamination method of the present invention, Fig. 2 is a block diagram schematically showing the entire decontamination equipment, and Fig. 3 is a transformer from which recycled oil has been extracted or a drying process. This is a schematic explanatory diagram of a device for overturning and raising the transformer.
The figure is an explanatory diagram of its operation, Figure 6 is a view in the direction of arrow A in Figure 4, Figure 7 is a schematic system diagram of the vacuum heating and drying equipment, and Figure 8 is a transformer showing an example of a state in which vacuum lubrication is performed. The vertical cross-sectional view and FIG. 9 are front views with a portion of the transformer using recycled oil cut away. 2, 10... Turning device, 4... Moving trolley, 6... Vacuum heating drying device, 12... Vacuum oiling device, 18... Rotating body, 24... Rotating roller, 50, 50a... Transformer,
53...Opening.

Claims (1)

[Scope of Claims] 1. A step of extracting the recycled oil in the transformer using a power means, etc., and after removing the recycled oil, turning the transformer upside down to drain the remaining oil in the transformer drippingly to drain the oil. The transformer, which has been drained of oil, is transported into a vacuum heating and drying device with its opening facing downward, and the transformer is heated to a temperature that allows the insulating material to be reused to impregnate the inside of the transformer body. There is a step of evaporating the remaining oil and impurities that have adhered to it, and drying it by forcibly exhausting it, and turning the transformer that has been subjected to the vacuum heating drying process so that the opening faces upward and pouring in new oil. A method for decontaminating a transformer using recycled oil, comprising the step of vacuum lubricating. 2 A ring-shaped rotating body is formed by fixing a pair of rotating wheels at a distance that allows the transformer to pass through with a cross beam so that they cannot fall over, and a pair of sliding bodies that sandwich the upper and lower parts of the transformer are installed so that the transformer can move up and down. A turning device for reversing and pulling up the transformer, which is configured by being rotatably mounted on a roller, and the transformer, which has been drained of oil, are placed in a vacuum heating dryer with the opening facing downward.
A movable trolley, which has a heating means for a transformer inside, and an exhaust means, which is connected to a means for liquefying evaporated substances and forcibly exhausts atmospheric gas to the outside, are integrally combined. a vacuum heating and drying device for vacuum heating and drying the transformer after being cut; a vacuum lubricating device for vacuum lubricating the transformer with insulating oil while continuing to evacuate the inside of the transformer that has been vacuum heated and dried; A decontamination device for a transformer using recycled oil, characterized in that it is equipped with a control device that performs sequence control.