The end point of vacuum drying equipment is automatically determined, and its function is high degree of automation.

Vacuum drying equipment is a new vacuum drying technology developed by the Institute of Automation in cooperation with foreign countries. It has changed the traditional drying method with high energy consumption, low efficiency and long cycle. It adopts the vapor phase drying technology with water vapor as the heat carrier. In the hot air heating stage, the vapor evaporated by the drying product and the filled dry air are used as the heat transfer medium, and the heat exchanger and the dried product are carried out. The heating uniformity is good and the heating efficiency is high. The drying process of portal air extraction is adopted, which has high heat transfer efficiency, short drying cycle and full automatic control. The equipment has the advantages of superior drying performance and low running cost. It is mainly used for vacuum drying treatment of transformers and transformers with various capacities below 220kV, 110kV and 110kV.

Variable pressure vacuum drying technology is a vapor phase drying technology with water vapor as the medium. The heat transfer efficiency is high, the drying cycle is obviously shortened, and the temperature of transformer body is uniform, and the drying degree is uniform.

It has the function of on-line automatic determination of vacuum drying end point of transformer with high degree of automation. The whole drying process is monitored by programmable logic controller. The influence of human factors on drying quality is completely eliminated. The equipment can be switched automatically or manually at any time, and the operation is stable and reliable.

Variable pressure vacuum drying equipment saves energy consumption, has no environmental pollution, no inflammable and explosive dangers, and meets the requirements of modern social industry.

Equipment investment intensity is small, operation and maintenance is simple.

The drying period is shortened by 30-50 compared with the traditional process.

The drying quality is good, and the final dry pressure is better than 100Pa.

Energy saving 30-50

Vacuum drying by pressure swing is divided into four stages.

1) preheating stage. In this stage, the tank is in a low vacuum, and the temperature between the winding and the core can be increased quickly and uniformly by convection heat transfer of steam with large heat capacity. During the preheating process, heating evaporation and water removal are carried out continuously, and the pressure in the tank varies from 80,000 Pa to 40,000 Pa, so as to ensure that the water vapor is unsaturated in the drying tank and eliminate the possibility of condensation of water vapor on the surface of the core. Such a reciprocating process makes the temperature distribution in the tank uniform, and can continuously evaporate water from the deep edge material. At this stage, the core temperature rises to 70 degrees, which can eliminate the moisture content of 35~45. According to the humidity of the environment, adjusting the holding time can prevent the core from rusting.

2) transition stage. At this stage, the vacuum level decreases from eighty thousand PPA to ten thousand PPA. At this time, the water is not much removed, mainly progressive vacuum and core temperature, for the main stage to prepare.

3) the backbone stage. It's called variable pressure dehydration stage.