JPH0345112Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hot air circulation type enamelled wire baking furnace.

[Prior art] Enameled wires used for winding of electric machines, etc.
After applying enamel varnish to a conductor, the conductor is run through a baking furnace to first evaporate the solvent component in the enamel varnish, and then crosslink and harden the resin, which is repeated.

Conventionally, the enamelled wire baking furnace was mainly a radiant furnace that utilized radiation heat transfer by a heater in the workpiece chamber, but in recent years, the baking speed has been increased. Hot air circulation furnaces, which feed heated hot air into a work chamber and utilize radiation heat transfer and forced convection heat transfer, have become commonplace.

FIG. 5 is an explanatory diagram showing the structure of the hot air circulation type enameled wire baking furnace. Burner 1 is the baking furnace.
It is composed of a catalyst 2, a circulation fan 3, an evaporation zone 4, and a curing zone 5. Air heated by a burner 1 is circulated by a circulation fan 3, and a running line 6 is formed.
Dry baking of enamel varnish applied to That is, the wire 6 introduced into the furnace from the inlet 10A evaporates the solvent component in the enamel varnish in the evaporation zone 4, crosslinks and hardens the resin in the curing zone 5, which is a high temperature heating area, and then passes through the outlet 10B. is led out of the furnace. On the other hand, the circulating air that heated the wire 6 running in the curing zone 5 and the evaporation zone 4 and the cold air flowing into the furnace from the inlet 10A and the outlet 10B are heated by the burner 1, and the solvent components evaporated from the enamel varnish by the catalyst 2. After being combusted, it is sent to the curing zone 5 again by the circulation fan 3, and at this time, a part of it is discharged from the furnace through the exhaust port 11.

[Problems to be solved by the invention] One of the most important quality characteristics of enamelled wire is surface appearance, and most of the defects in surface appearance occur during the baking process in the evaporation zone.
In order to prevent such surface appearance defects, it is necessary to select optimal baking conditions such as wind speed and temperature distribution, depending on the resin component in the enamel varnish to be used. However, in the hot air circulation type enameled wire baking furnace, only the speed and temperature of the hot air blown into the hardening zone can be controlled, and the temperature distribution in the evaporation zone is independent of the hardening zone, as in the case of a radiant furnace. Therefore, it was difficult to set it to an arbitrary value. For this reason, it is difficult to take appropriate measures against surface appearance defects caused by the heating process in the evaporation zone, and it has not been possible to adequately respond to the wide variety of enamel varnishes desired by users.

[Means for solving the problems] The present invention was developed as a result of intensive studies in view of the above points, and its purpose is to improve the heating process in the evaporation zone for a wide variety of enamelled wires. To provide a hot air circulation type horizontal enamelled wire baking furnace capable of preventing surface appearance defects caused by.

That is, the present invention provides a hot air circulation type horizontal enamelled wire baking furnace, which is characterized in that the furnace inlet is provided with a bypass passage for cold air flowing in from outside the furnace and a damper for adjusting the volume of the cold air. This is an enameled wire baking furnace.

As the air volume adjustment damper used in the present invention, a sliding damper whose position can be adjusted may be provided at the bypass passage opening, or a slide damper whose position can be adjusted may be installed at the furnace circulating air intake in the bypass passage from outside the furnace. There is no problem in providing a butterfly type damper that can adjust the air volume. The latter case has the advantage that the amount of cold air flowing into the furnace can be easily adjusted.

In addition, as a method for providing a bypass path for cold air flowing from outside the furnace into the furnace inlet, a simple method is to attach a partition plate to the inlet of an existing conventional hot air circulation type enameled wire baking furnace, and It is also possible to provide a cold air bypass path.

[Function] In the baking furnace of the present invention, a bypass passage for cold air flowing from outside the furnace and a damper for adjusting the volume of the cold air are provided at the furnace inlet, so that the evaporation rate can be adjusted depending on the type of enamel varnish used. wind speed in the band,
Temperature distribution, etc. can be set to optimal baking conditions, and it is possible to prevent surface appearance defects of the enameled wire caused by the heating process in the evaporation zone.

[Examples] Next, the present invention will be explained in more detail with reference to Examples. FIG. 1 is an explanatory diagram showing an example of the structure of a horizontal enamelled wire baking furnace with hot air circulation according to the present invention.
1 is a burner, 2 is a catalyst, 3 is a circulation fan, 4 is an evaporation zone, the rear is a curing zone, 6 is a running line, 7 is a partition plate,
8 is a sliding damper, 9 is a cold air suction bypass passage, 10A is a furnace inlet, 10B is a furnace outlet, 11
is an exhaust port.

The partition plate 7 attached to the furnace inlet 10A allows
A cold air suction bypass path 9 is provided, and by adjusting the amount of air blown into the cold air suction bypass path 9 by moving the sliding damper 8 in the vertical direction, air flows into the evaporation zone 4 from the furnace inlet portion 10A. The amount of cold air can be adjusted, and the wind speed and temperature distribution in the evaporation zone 4 can be set so as to obtain desired baking conditions.

An enameled wire baking furnace with the above structure was manufactured by modifying the vicinity of the furnace inlet 10A of a conventional horizontal hot air circulation type enameled wire baking furnace, and the amount of air sucked into the bypass path 9 was changed by changing the opening degree of the slide type damper 8. An esterimide wire was manufactured while adjusting the At this time, the surface appearance properties of the enameled wires produced at each opening were observed and compared, and at the same time, the wind speed and temperature distribution in the evaporation zone 4 were measured. Some of these results are shown in the second
It is shown in Figures a to c and Figures 3a and b. That is, FIGS. 2 a to c show the opening degrees of the damper 8 of 0, 50, and 50, respectively.
It is an explanatory diagram showing changes in the flow of cold air flowing in from outside the furnace and circulating air in the furnace in the evaporation zone 4 when it is set to 100%, and the flow of the cold air and the circulating air in the furnace varies depending on the opening degree of the damper 8. pattern has changed significantly. FIG. 3b is an explanatory diagram showing the temperature distribution in the evaporation zone 4 and the surface appearance properties of the obtained enameled wire when the damper opening degree is changed in the same way. It was found that the temperature distribution and the surface properties of the enameled wire in Example 4 changed significantly, and that by appropriately adjusting the damper opening depending on the type of enamel varnish, an enameled wire with good surface quality could always be obtained. Note that FIG. 3a shows the temperature measurement positions (TC0 to TC6) in FIG. 3b.

FIG. 4 is an explanatory diagram showing another embodiment of the present invention in which a butterfly damper 12 is used as a damper for adjusting the volume of cold air flowing in from outside the furnace. The amount of cold air can be adjusted by an operation from outside the furnace, and the amount of cold air can be adjusted more easily.

[Effects of the invention] According to the baking furnace of the invention, the wind speed, temperature distribution, etc. in the evaporation zone can be set to optimal baking conditions to obtain good surface quality, depending on the type of enamel varnish used. It has remarkable industrial effects, such as being able to manufacture a wide variety of enamelled wires according to the wishes of users.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an embodiment of a hot air circulation type horizontal enameled wire baking furnace according to the present invention, and Figs. 2 a to c
is an explanatory diagram showing the influence of the opening degree of the damper in the enameled wire baking furnace on the flow of the circulating air in the furnace in the evaporation zone, and FIG. FIG. 3a is an explanatory diagram showing the temperature measurement position in FIG. 3b, and FIG. FIG. 5 is an explanatory diagram showing the structure of a conventional hot air circulation type enamelled wire baking furnace. 1... Burner, 2... Medium, 3... Circulation fan, 4... Evaporation zone, 5... Curing zone, 6... Running line, 7... Partition plate, 8... Sliding damper, 9
...cold air suction bypass path, 10A ...furnace inlet section,
10B... Furnace outlet section, 11... Exhaust port, 12...
Butterfly damper.

Claims (1)

[Scope of claims for utility model registration] (1) In a hot air circulation type horizontal enamelled wire baking furnace,
A hot air circulation type enameled wire baking furnace, characterized in that a bypass passage for cold air flowing from outside the furnace and a damper for adjusting the volume of the cold air are provided at the furnace inlet. (2) The hot air circulation type enameled wire baking furnace according to claim 1, which is characterized in that a sliding damper is provided at the opening of the bypass passage. (3) The hot air circulation type enameled wire baking furnace according to claim 1, which is characterized in that a butterfly damper is provided at the in-furnace circulating air suction port in the bypass passage. (4) The hot air circulation type enameled wire baking furnace according to claim 1, which is characterized in that a cold air bypass path is provided by a partition plate attached to the furnace inlet.