真空浸漆绝缘工艺研究

真空压力浸漆绝缘工艺研究Insulation Technology Study about Vacuum PressureImpregnation1 真空压力浸漆（简称：VPI）绝缘工艺1 Vacuum Pressure Impregnation (VPI) Insulation ProcessVPI-真空压力浸渍工艺是将工件预烘去潮后冷却，置于真空环境中，排除白坯线圈内部的空气和挥发物，依靠真空中漆液重力和线圈毛细管作用，以及利用干燥的压缩空气或惰性气体，对解除真空后的浸渍漆液施加一定压力的作用，使漆液迅速渗透并充满绝缘结构内层。

在国内，目前VPI还是一种间隙作业的绝缘工艺。

工件的滴干工序在浸漆罐内进行，其干燥工序一般另设容器或烘箱进行，方式有真空干燥、常压静置干燥或旋转干燥。

The process of VPI-Vacuum pressure impregnation technology is to cool the workpiece after pre-baking and dehumidify, then put it into vacuum environment and exhaust air and volatiles inside the coil. After that put pressure on the impregnation varnish liquid by depending on the action between liquid gravity and coil capillary and utilizing dry compressed air or inactive gas, then the varnish liquid will penetrate and be full of inner of insulation. So far, the VPI process is a discontinuous operation at home. The process of drip-dry works in impregnation cans. And the drying process works in the other heating devices, the methodsinclude vacuum drying, stranding drying at ordinary pressure and rotating drying.VPI-工艺流程：⊙→预烘除湿→入罐→真空排气→真空浸漆→压力浸渍→压力排漆→卸压滴漆→出罐→固化干燥→⊙。

VPI-process: ⊙→pre-baking and to dehumidify→workpiece into the vacuum exhaust tank→vacuum exhaust→vacuum impregnation→pressure impregnation→pressure remove paint→relief pressure, dripping paint→workpiece out the tank→curing baking→⊙.比较：显然，VPI在漆液渗透方面和浸渍方面，远远优于其它浸漆工艺。

在应用方面，VPI更适合大型高压线圈、多层齐绕磁轭线圈和要求较高的大型绕组、以及其它高压线圈。

理论上，VPI的应用，真空和压力可以做得相当的高，当然成本也高了。

FGH则不然，由于连续作业，以及产量和成本的具体要求，其应用具有一定范围的限制。

Make a comparison: Obviously, the varnish liquid penetration and impregnation of VPI is superior to the other technology. In terms of application, VPI better suits the large-scale high voltage coil, multilayer magnetic yoke coil, demanding large-scale coil and other high voltage coil. In theory, vacuum and pressure can achieve quite high while applying VPI, the costis high at the same time. On the contrary, FGH is not the case. Because of the continuous operation and the specificrequirements of production and cost, which limit the range of application.在应用试验和实际工作中，我们发现，真空环境对于某一温度条件下的一种浸渍漆液，当其真空度低于某一绝对压力的数值时，亦即达到某一对应的“临界”真空时，会导致该浸渍漆液中大量泡沫和液面大量雾气的产生，即发生“沫化”和“雾化”现象。

“沫化”造成漆液中大量空穴，会阻碍浸渗。

“雾化”致使溶剂或稀释剂大量逸出，会影响固化。

In the application testing and actual operation, we found that it exists one kind of varnish liquid under one certain degree in vacuum. When the vacuum degree is lower than the absolute pressure value or up to a certain “critical” vacuum, it will produce a lot of foam and mist in the varnish liquid. This phenomenon is called “foaming” and “nebulization”. “Foaming” will cause a lot of void in varnish liquid and influence the infiltration. “Nebulization” will cause lots of solvent or thinner overflow and influence solidification.对于压力，原则上加压是为了使漆液更容易进入填充空隙，输漆过程实际上就有一个大气压。

如果绝缘结构内毛细管的润湿性已经平衡，则增加压力对整个绝缘结构的填充并无明显作用，除非在固化时一直维持增加的压力，所以，增加填充的有效途径，是降低漆的粘度和减小绝缘结构空隙、提高毛细管效应，而不是提高压力。

根据“粘度与压力对渗透速率”的试验，其数据显示：当漆液粘度较大时，增大压力对填充速度有较大作用，在漆液粘度小时，增大压力对填充速度的作用不显着。

然而，漆液粘度却对填充速度具有十分显着的影响，二者呈反比关系。

In principle, the pressure is to make the varnish liquid filling voids easier. Actually, there is one atmospheric pressure in the process of transporting the varnish liquid. Unless to maintain the pressure in the process of curing, or there is no obvious effect to increase pressure on the whole insulation structure if the capillary in the structure has achieved balance of wettability. Therefore, the effective method to increase the filling is to reduce viscosity of varnish, minish the insulation gap and improve the capillary effect, instead of increasing the pressure. According to test of “viscosity and pressure on the permeation rate”, the data shows that: Add the pressure has great effect on the speed of filling when the varnish liquid is in larger viscosity. On the other hand, it’s not obvious of the filling speed while add pressure if the varnish is in low viscosity. However, the viscosity of the varnish has significant impact on the filling speed, there exists inverse relationship between the two aspects.由此可见，在VPI工艺的应用中，片面强调和单纯追求高真空或高压力，是盲目和无益的。

其结果会影响浸渍效率，甚至会破坏浸渍质量。

一种工艺对不同的绝缘结构以及不同的技术要求，其实际工艺参数也各不相同。

譬如VPI共有四种工艺参数，即真空Vi、压力Pi、温度Ti、时间ti，其中i为1、2、3、…….，n（n是VP工艺工序的总数，i是工序次序）。

绝缘结构（W）、技术指标（A）、漆液特性（E）是这四种工艺参数的基本函数元素。

Thus it’s useless and blind to emphasis and pursuit the high vacuum or high pressure in theapplication of VPI process. The result will affect the efficiency of impregnation and even destroy the quality. One process has different insulation structure and different demands on technology, and the actual process parameters are varied. For example, there are four parameters in VPI process, namely vacuum Vi, pressure Pi, temperature Ti, time ti. And “I” means 1, 2, 3…, n (“n” is the total number of VP, and “I” is t he order of process). The basic function elements of the four process parameters are insulation (W), technical indicators (A) and varnish liquid properties (E).2 电机、变压器绕组的浸漆绝缘处理工艺2 Impregnation insulation process of motor and transformer coil.从沉浸即普通浸渍到多次浸渍，又到滴漆，滚浸和真空浸漆，真空压力浸渍发展到工艺连续的普通沉浸，滴漆和滚浸，最后到真空浸漆烘干一体化，形成了一系列多样的机械化连续作业，应用现代计算机技术和PLC技术自动化控制的浸渍工艺，这是不断地通过技术革新，生产需求和社会发展的推动，逐步演变发展，正是这种推动，又产生了新一代真空浸漆烘干机，节能、环保成一体的高新技术产品、名牌产品，国内外近600家用户使用。