Vacuum Hot Air Drying Equipment – Providing a Reduced Drying Time

In a comparison of our vacuum hot air drying systems and conventional drying systems that are only operated at atmospheric pressure without vacuum, one characteristic clearly stands out: The drying time is reduced by nearly 50%. HEDRICH vacuum hot air drying equipment can be used for many applications. Benefit from our innovative drying technology and excellent drying results.


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Controlled Air Guidance

In the air circulation system, the heat transferring medium air is circulated by means of fans between the heated autoclave wall and air baffles so that the air is heated up and conducted to the parts to be dried which are uniformly dried. The exchange of air enriched with water vapour is efficiently controlled by a moisture sensor.


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Customized Design

We construct our equipment individually according to your specifications to achieve optimum and energy-efficient drying performances. Depending on the application, round or rectangular autoclaves are used. Also for vacuum pumping units with oil-sealed or dry-compressing backing pumps, HEDRICH meets the specific customer requirements and designs optimum solutions.


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Time Reduction by Current Heating

For reducing the time for drying, the vacuum air circulation drying systems can additionally be provided with a direct current heating. This solution is preferably used to dry windings. The combination of resistance heating and air circulation heating ensures a faster and more uniform heating thus increasing the energy efficiency.


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Uniform Heating

HEDRICH heats the complete autoclave with all surfaces, including top, bottom, rear wall and door. The temperature is controlled via different heating circuits, with manual control valves. The typical heating medium is heat transferring oil that is pumped through U-shaped pipes welded on the autoclave. With smaller autoclaves, heating is also possible through electric heating plates installed at the outside.


Advantages of vacuum hot air drying equipment

• Control of circulating air to be exchanged by a moisture sensor
• Optimized and uniform heat distribution through fans and air baffles
• All-around heating of autoclave by means of heat transferring oil, including door
• Further reduction of the drying time up to 75% by additional use of a current heating device to heat the windings
• Loading by air cushion vehicle or trolley
• Online registration of dew point and water rate during the fine vacuum phase


• Distribution transformers
• Power transformers
• High-voltage instrument transformers
• High-voltage bushings
• Components for transformers
• Transformer windings
• Traction transformers

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