JPS5919613B2 - Method for manufacturing enamel insulated wire and equipment for manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method and apparatus for manufacturing an enamel insulated wire,
In particular, the present invention relates to improvements in equipment having a vertical baking furnace.

Enamel insulated wires are usually manufactured by applying enamel to an annealed copper wire or aluminum wire using a vertical enamel baking device and baking the wire.

As shown in FIG. 1, the vertical enamel baking apparatus has a lower opening 3 at the lower end of a baking furnace 1 having a built-in heater 2, and an upper opening 10 at the upper end. An air shielding plate 4a34b that opens and closes is provided, and a die 6 held by a die holder 7, a paint tank 8, and a turn sheave 9 are sequentially provided thereunder. The aluminum wire W (hereinafter referred to as wire) was passed through a turn sieve 9 into a paint tank 8 to coat its surface with paint, and then the die 6 was used to adjust the coating amount to a uniform and constant amount. Back, lower opening 3
It has a structure in which it is baked through a baking furnace 1, cooled through an upper opening 10 through a cooling chamber 11, and pulled out through a turn sheave 12. Normally, this operation is repeated 6 to 8 times, but in consideration of economic efficiency. It is common to manufacture 10 to 30 pieces at the same time in the same baking furnace, with two sizes of one furnace stacked on the left and right. In this manufacturing process, solvent gas is generated when the enamel paint applied to the wire W is heated by the heater 2 to evaporate the solvent and harden the paint film. A chamber 13 is provided, and the combustion chamber 13 is provided with a preheater 14 and a catalyst 15, and the gas is heated as necessary by the preheater 141, and then reacted and combusted by the catalyst 15. The structure is such that a portion is released into the atmosphere and a portion is circulated within the furnace 1 and reused for heating for baking.

In addition, since the baking furnace 1 generates an upward air current due to the chimney effect of the vertical furnace k, a gap 17 is provided at the outlet of the upper opening 10, and new air at high speed is blown from the outside into the gap 17 to prevent this so-called structure. An air curtain device is provided. Note that 18 is an exhaust passage of the air curtain device.

The effective length of the rigid enamel baking furnace 1 varies depending on the type of furnace, but the standard is usually 5 to 8 m, and the baking temperature varies depending on the type of enamel paint and baking conditions. The upper part of the furnace is 400-500℃, the middle part of the furnace is 35℃.
It is normal to set the temperature in the range of 0 to 450°C and 200 to 350°C in the lower part of the furnace. The above is an explanation of the structure of a typical conventional printing device.In addition to this, devices with various improvements to the solvent gas catalyst and combustion system are being considered.However, as mentioned above, conventional hard enamel printing devices The printing device 1 has the following drawbacks.

First, the amount of air entering the baking furnace 1 becomes excessive.

It is necessary to introduce air into the furnace 1 because the enamel paint solvent gas that is constantly generated in the furnace 1 during the manufacture of enamel insulated wires is combusted by a catalyst. Therefore, it is sufficient to introduce the amount of air necessary to completely burn the solvent gas into the furnace 1. In this case, the problem of incomplete combustion occurs.

For example, this required air amount is now JIS for wire diameter 0.9 cod.
Type L polyester imide wire is heated in a rigid enamel baking furnace.
Honkake, set the furnace temperature to 450℃ in the upper part, 350℃ in the middle, and 300℃ in the lower part.
℃, and a baking line speed of 20 m/min is used to manufacture polyester imide paint (resin content: 33%, meta-cresol: 60%, petroleum naphtha: 7%). If the air ratio is 1.2, the air volume is approximately 8901/min at 20°C.

However, the air shielding plates 4a, 4 as shown in FIG.
The air shielding plates 4a, 4 are separated by the gap b between the running strands W.
Due to the need to prevent contact with b, the interval is 15 to 20
The actual situation is that due to the chimney effect of the vertical furnace and the circulating air in the furnace, an excessive amount of air is drawn in, which is 5 to 7 times the required air amount. In addition, baking furnace 1
The upper opening 10 has a so-called air curtain structure in which high-speed airflow is blown from the outside through a gap 17 to prevent rising airflow from inside the furnace 1. Because the hot gas inside the furnace comes into contact with the cold air from the air curtain outside, the unburned solvent and short-molecule resin contained in the exhaust gas condense over time. However, if left as is, it will have a serious adverse effect on the product, so there is also the drawback that the furnace 1 must be shut down for a short period of time for cleaning and maintenance.

Furthermore, since the structure of the baking furnace 1 is such that exhaust gas heat after catalytic combustion is circulated and reused within the furnace 1, if one side of the parallel baking furnaces is shut down due to a size change, etc., once the combustion of the exhaust gas has stopped, A subtle temperature change occurs instantaneously that cannot be compensated for by heater 2, which seriously affects the product being manufactured on the other side.

This phenomenon also occurs when the engine is restarted after being inactive. This is thought to be due to the fact that the left and right baking furnaces are integrated, so they are not structurally independent, and the heater 2 is also integrated, making the temperature control system, circulation system, and blower all integrated. .

In view of these points, it is an object of the present invention to provide a method and apparatus for manufacturing an enamel insulated wire that solves the above-mentioned drawbacks. Enamel insulation involves uniformizing the enamel paint layer on the conductor to a predetermined thickness, volatilizing and separating the solvent in the enamel paint layer through a high-temperature baking furnace, and baking the enamel paint onto the conductor, which is then cooled and solidified through a cooler. In the method for manufacturing electric wires, air is mixed with the volatilized and separated solvent vapor, the mixture is combusted to produce high-temperature gas, and after this high-temperature gas is used to heat the solvent vapor mixing air, a part of it is is used to heat the baking furnace, and the remainder is discharged to the outside of the system, while the air heated by the high-temperature gas is heated by an air curtain device installed at the outlet of the baking furnace before being used for combustion of the solvent. A first invention of a method for manufacturing an enamel insulated wire used as air;
In an apparatus for manufacturing enameled insulated wire, the baking furnace has a lower opening at the lower end and an upper opening at the upper end. In addition to providing a sealed chamber in the lower opening, a combustion furnace and a heat exchanger are newly installed, an air inlet is connected to the heat exchanger, and a space between the heat exchanger and the air curtain device and the upper part of the baking furnace is installed. An apparatus for manufacturing an enameled insulated wire, comprising a ventilation passage between the combustion furnace, between the combustion furnace and the heat exchanger, and between the exchanger and the lower part of the baking furnace or the sealed chamber. This relates to the second invention.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 4.

In FIG. 2, reference numeral 20 denotes a vertical baking furnace that includes a built-in heater 21 and has a lower opening 22 at the lower end and an upper opening 23 at the upper end. Seal tightly.

The closed chamber 24 is designed to be able to be opened and closed in order to enable line hanging work. The sealed chamber 24 is provided at its lower end with a passage hole 26 through which the wire W passes, and this passage hole 2
A removable die holder 28 is provided adjacent to 6 and a die 27 is attached thereto, and an enamel paint tank 29 is provided below it.

This paint tank 29 can also be provided integrally with the die holder 28. Reference numeral 30 denotes a combustion furnace equipped with a catalyst 32. One end of the combustion furnace 30 communicates with the tip of the baking furnace 20, and the other end of the combustion furnace 30 communicates with one end of a heat exchanger 37.

Further, the other end of the heat exchanger 37 and the lower end of the baking furnace 20 are communicated through a ventilation passage 33.

The heat exchanger 37 has a fresh air intake port 34 from the outside.
a and a heated air outlet 34b, and this heat exchanger 3
The heated air outlet 34b of No. 7 is connected to the upper opening 2 of the baking furnace 20.
3 is connected to the nearby air curtain device 35. 36 is a blower (equipped with a variable speed motor) built into the combustion furnace 30, which sucks the air blown into the air curtain device 35 and the solvent vapor generated in the furnace 20 into the combustion furnace 30, and
The high-temperature gas generated by burning the solvent vapor in the furnace 30 is passed through the heat exchanger 37 and the ventilation passage 33 to the baking furnace 2.
0 or the sealed chamber 24 into the baking furnace 20.

Further, the heated air passage 34b is used to send air heated by the heat exchanger 37 using high temperature gas as a heating medium to the air curtain device 35. Furthermore, a damper 38 and a flow meter 39 are provided in the ventilation passage 33, and the furnace 20
A variable speed propeller motor (36.
It is effective to adjust it with M).

In addition, 40 is a discharge passage for excess high temperature gas, 41 is a cooling chamber,
42 and 43 are turn sheaves.

The strand W is passed through the paint tank 29 via the turn sheave 42 to coat its surface with paint, and then the die 27 adjusts the paint to a uniform layer thickness, and then the wire W is passed through the passage hole 26 into the sealed chamber. 24, and then passed through the lower opening 22 into the baking furnace 20 for baking, passed through the cooling chamber 41, cooled and solidified, and pulled out through the turn sheave 43 to produce an enameled insulated wire. is sealed in a closed chamber 24 to block outside air, and inside the baking furnace 20, high temperature air heated by the heat exchanger 37 blown from the passage 34a and solvent vapor generated inside the furnace 20 are mixed. Only the high temperature gas produced in the combustion furnace 30 with the mixed gas is circulated. Therefore, the air into the baking furnace 20 is high-temperature air that has been heat-exchanged by the necessary minimum amount of 8901/min through the passage 3.
It can be introduced from 4a, and the minimum amount of air required for exhaust is 890
1/min (23001/min at 450° C.), heat loss within the furnace 1 can be minimized and heat transmission can be utilized to the maximum. For example, the solvent gas metacresol and petroleum naphtha generate the following combustion heat in a baking furnace.

1P! When this combustion heat is manufactured under the manufacturing conditions described in the example above, energy equivalent to approximately 45 KW of electric power will be generated per hour, but as described above, according to the present invention, this energy can be minimized. Can be used effectively at a loss.

However, with conventional baking furnaces, cold air from outside is introduced through the opening at the bottom of the baking furnace, so even if hot air is circulated to the bottom of the furnace, the temperature at the bottom of the furnace will inevitably drop, and Thermal energy loss also increases.

In addition, if the lower opening 22 of the baking furnace 20 is sealed to block external air as in the present invention, and if the hot air is circulated, for example, the upper opening 22 is sealed.
It was possible to set the temperature to 0°C, 450°C in the middle, and 450°C in the lower part, and it was confirmed that there was no difference in the characteristics of the enamel insulated wire even under these conditions.

Furthermore, air inflows through the passage 34 and exhaust air flows through the exhaust passage 40.
Therefore, it is easy to control the amount of air inflow and air exhaust. For example, this can be easily done by adjusting the valve. Furthermore, since the air curtain device 35 in the upper part 1ζ of the baking furnace 20 uses high-temperature air heat-exchanged in the heat exchanger 37,
Even if it is possible to completely prevent the condensation of the solvent and polymers in the unburned matter due to the upward airflow inside the furnace 20 at the upper opening 23, cleaning and maintenance of this part is no longer necessary.

However, even with the above structure, if the parallel left and right baking furnaces 20 are the same in terms of structure and electrical control, when one side of the furnaces 20 is used for wire hanging work due to size exchange, etc., the sealed chamber 24 By opening the furnace 20, a large amount of air is instantly sucked into the furnace 20, and the temperature change in the furnace 20 becomes even more pronounced, which has a serious negative effect on the product being manufactured on the other side.

To solve this problem, either the left and right sides of the baking furnace 20 are completely separated, or the two baking furnaces 20 of one size: It is advisable to adopt the former method. For example, specific examples thereof are shown in Figs. 3 and 4. Fig. 3 is a central vertical cross-sectional view, and Fig. 4 is a cross-sectional view of Fig. 3A-A. It is a line cross-sectional view, and the same reference numerals indicate the same parts as in Fig. 2.As explained above, the present invention is capable of dividing the baking furnace into left and right parts, sealing the lower opening of the baking furnace, and minimizing the amount of air required from the upper part of the baking furnace. With the introduction of a heating system and the effective use of energy through hot air circulation, it is possible to use 0.23 KWH per firing furnace to produce 1 kf1 of enamelled copper wire of 25 KW per 1 hour under the manufacturing conditions described in the example above. Obtained results on power consumption.

Furthermore, in the present invention, it has been confirmed that for paints with a high solvent content, such as formal resin paints, the rate of combustion heat generated in the furnace naturally increases, so that the power consumption is further reduced. The above description has been about heater heating using electric power, but the present invention also applies to heating using combustible gas, such as city gas, L. N.
Of course, it can also be applied using combustion heat such as G. The concentration of metacresol etc. before combustion in the catalyst 32 is approximately 2% when the minimum required air flow rate of 8901/min is introduced into the furnace 20, which exceeds the lower explosive limit concentration of metacresol of 1.06%. Since there is a risk of explosion due to some reason, the rate at which meta-cresol etc. is burned in the catalyst 32 should be set at least 2 times per minute (usually 5 to 15 times).
The furnace 20 is forcibly circulated by a blower 36 so as to burn at a rate of 20%, and the reactor is designed to react steadily at an absolute concentration below the lower explosive limit concentration.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional example, and Fig. 2 is a central longitudinal sectional view showing an embodiment of the present invention. Fig. 3 is a central vertical cross-sectional view showing an embodiment in which the baking furnace is of the left-right split type, and Fig. 4 is Fig. 3 A-A.
FIG. 20... Baking furnace, 21... Heater,
22... Lower opening, 24... Sealed chamber,
30... Combustion furnace, 32... Catalyst, 34
...Air passage, 35...Air curtain device, 36...Blower, 37...Heat exchanger, 33...Vent passage .

Claims (1)

[Claims] 1. Applying enamel paint onto the conductor through a paint tank, homogenizing the enamel paint layer on the conductor to a predetermined thickness through a die, and volatilizing the solvent in the enamel paint layer through a high-temperature baking furnace. After separating and baking enamel paint on the conductor,
In a method for manufacturing an enameled insulated wire that is cooled through an air curtain device and a cooler, the volatilized and released solvent vapor is extracted from the upper part of the baking furnace to the outside of the furnace, and air from the air curtain device is mixed with it. After burning to produce high-temperature gas and using this high-temperature gas to heat the solvent vapor mixing air, a part of the high-temperature gas is used to heat the baking furnace, and the remainder is discharged to the outside of the system, On the other hand, a method for producing an enameled insulated wire, characterized in that the air heated by the high-temperature gas is used as air for an air curtain device provided at the outlet of the baking furnace before being used for combustion of the solvent. 2. An enameled insulated wire manufacturing apparatus comprising a vertical baking furnace having a lower opening at the lower end and an upper opening at the upper end, a die and a paint tank disposed below the baking furnace, and an air curtain device near the upper opening. At the same time, a combustion furnace and a heat exchanger are installed separately, an air inlet is connected to the heat exchanger, and a closed chamber is provided at the lower opening of the baking furnace. and the combustion furnace, between the combustion furnace and the heat exchanger, and between the heat exchanger and the lower part of the baking furnace or the sealed chamber. Device. 3. The apparatus for manufacturing an enameled insulated wire according to claim 2, wherein the combustion furnace is a combustion furnace in which a blower and an oxidation catalyst are disposed and built in from the air passage side of the air curtain device side of the combustion furnace.