Vacuum Drying Ovens for delicate drying processes such as drying tiny parts or removing flammable solvents.
Vacuum ovens are very adaptable pieces of equipment with applications in laboratory research, engineering as well as several industry. A vacuum drying oven is most often utilized for delicate drying processes, such as drying tiny parts or removing combustible solvents. The low pressure environment also reduces oxidation during drying.
A standard vacuum oven may work at temperatures as high as 200C to 250C. A rugged, high quality pressure chamber, gasket seals as well as pump are features to look for, as well as convenient, programmable controls as well as a computer interface. Vacuum drying ovens are also available with specialized features such as solvent recovery or residual gas analysis to stop over drying. For drying flammable solvents, look for a security vacuum drying oven that has been approved for these types of applications.
A vacuum drying oven generally has a chamber volume of between 20 and 150 litres and a temperature range beginning at between +5 °C and +15 °C beyond room temperature up to +250 °C; some appliances may also work at up to 400 °C (see details on the basic operation and fittings of a temperature control chamber).
The interiors are designed of corrosion-free stainless steel 1.4301, resistant to most acids or the more robust 1.4404. Some manufacturers of vacuum drying ovens in addition smooth the interior and the sliding shelves by means of electrolytic polishing to make cleaning easier.
A vacuum drying oven is suggested for delicate drying processes, for example, drying smaller items and/or the removal of flammable solvents.
In cannabis processing, vacuum ovens are also utilized to strip concentrates (oils) of residual solvents such as butane and CO2 before they are put on the market. For this reason, a vacuum oven uses a combination of heat as well as negative pressure (vacuum technology) that ends up stripping the concentrated material of any residual solvents that were utilized in the extraction process.
Direct heating of the chamber load
Since heat transfer cannot take place in a vacuum, the chamber load is heated or dried through straight contact with a heated surface. Two basic heating systems operate here in practice: Heat transfer from the side walls to the sliding shelves (with or without heated air jackets) or nonstop heated carrier plates/shelves. With air jackets, the warmth of an air chamber around the interior supports homogenous temperature distribution inside the chamber. However, this method is time-consuming. With plate heating, the straight heated sliding shelves transfer heat to the chamber load thus shortening the drying time. In addition to digital temperature control, various manufacturers also offer a digital pressure control, allowing the programming of defined temperature / vacuum cycles.
Vacuum pumps
Vacuum is created by vacuum pumps. If various vacuum drying ovens are operated simultaneously, they are often connected to a central vacuum supply. Depending on the needs of suction power, lifetime or end vacuum as well as depending on the application (chemical resistance, oil-free operation, fumes released, etc.), membrane pumps, rotary vane pumps or scroll pumps may be utilized for low as well as medium vacuum applications.