Vacuum pressure paint dipping equipment
VPI is the English abbreviation of vacuum pressure impregnation process. VPI vacuum pressure impregnation equipment is an important process equipment in the production process of electrical appliances and electrical materials such as high-voltage motors, transformers, power capacitors and paper insulated high-voltage power cables. After VPI process treatment, the insulation performance is good, the temperature rise is reduced, the efficiency is improved, the mechanical strength is increased, and the looseness in the operation process is solved Prevent short circuit and other insulation faults, improve moisture resistance and prolong service life.
In the 1970s, several domestic motor manufacturers made VPI equipment by themselves, but due to the immature technology and poor performance of the equipment, they did not arouse the interest of other motor manufacturers. Later, in order to ensure the quality of traction motor, the Railway Department tried out VPI technology in a certain scale of enterprises. At the end of last century, the production and repair of online motor in the railway industry were all changed to VPI technology, which promoted the rapid development of VPI equipment manufacturing level.
In order to reduce the manufacturing cost, shorten the manufacturing cycle and improve the quality of motor manufacturing, vacuum pressure impregnation technology has been popularized.
Vacuum pressure paint dipping equipment process application:
VPI is far superior to other impregnation processes in terms of paint penetration and impregnation. In application, VPI is more suitable for large-scale high-voltage coils, multi-layer wound yoke coils, large-scale windings with higher requirements, and other high-voltage coils. In theory, the application of VPI, vacuum and pressure can be quite high, of course, the cost is also high, In applied experiments and practical work, we found that in a vacuum environment, when a vacuum impregnating varnish under a certain temperature condition, when its vacuum is lower than a certain absolute pressure value, that is to achieve a corresponding "critical" vacuum, it will cause a large amount of foam and liquid mist in the impregnating varnish, which means "foam" and "atomization" phenomenon. "Foaming" causes a large number of holes in the paint liquid, which will hinder infiltration. "Atomization" causes a large amount of solvent or diluent to escape, which will affect the curing. For pressure, in principle, pressure is used to make the paint liquid easier to enter the filling gap. In fact, there is a atmospheric pressure during the paint transportation process.
If the wettability of the capillary in the insulation structure has been balanced, the increase of pressure has no obvious effect on the filling of the whole insulation structure, unless the increase of pressure is maintained all the time during curing. Therefore, the effective way to increase the filling is to reduce the viscosity of the paint, reduce the gap of the insulation structure, improve the capillary effect, rather than increase the pressure. According to the test of "viscosity and pressure on penetration rate", the data shows that: when the viscosity of paint liquid is large, increasing pressure has a greater effect on filling speed, but when the viscosity of paint liquid is small, increasing pressure has no significant effect on filling speed. However, the viscosity of paint liquid has a very significant impact on the filling speed, which is inversely proportional. It can be seen that in the application of VPI process, it is blind and useless to emphasize and simply pursue high vacuum or high pressure. The results will affect the impregnation efficiency and even destroy the impregnation quality.
Vacuum pressure paint dipping equipment operation process:
1. Check whether the power supply and air source switch are normal;
2. Open the manual operation "vacuum, lifting and air bleeding" once to confirm whether the equipment operates normally;
3. After confessing to be correct, pour the prepared materials into the chat tray;
4. Put in the first product, dip the depth of the debugger and the rise and fall speed of the confessing material tray. Generally, adjust the speed regulator to about 25 for fast rise and fall, and adjust the speed regulator to (10-15) for slow fall, set according to the height of the product, and adjust the time according to the process requirements to display the adjustment time of the regulator, and adjust the real time;
5. After the commissioning is OK, turn off the manual, turn on the automatic, and conduct preliminary operation;
6. At the end of each day, it is necessary to turn off all switches in turn and keep the panel clean;
7. Require the person in charge to perform and turn off all switches every day, and keep the panel clean;
8. The person in charge is required to perform the maintenance of vacuum paint dipping machine and equipment and make records every day.