Vacuum ovens are ideal for industrial heating processes where a high quality of the piece and consistency of the heating is required.
Strong brazing or heat treatment in a high vacuum environment offers a superior degree of process control and produces exceptionally clean, rust-free parts. In a vacuum system, the parts are loaded in a steel chamber from which air and other gases are extracted. Contrary to the heating by flame and resistance, a vacuum furnace heats the entire piece and not just the joint area.
Traditional vacuum ovens are large structures fed by banks of electric heating elements. These large furnaces need several hours to reach and maintain the temperature.
The advantages of induction heating are:
•Improvement of efficiency
•Reduction of operating expenses
•They provide an excellent example of green technology
•The pieces to be heated can have almost any shape
•Cycle times are reduced
•Easy loading and unloading of parts
•Maximizes operator safety
•Improve the work environment
•It has compact dimensions that easily adapt to any manufacturing cell
Some of the related industries are aerospace, defense, medicine, universities, research and development.
Vacuum furnaces are frequently used in industrial heat treatment processes and vary widely in capacity and size. Over the past 30 years, equipment has benefited from continuous improvements so that the use of vacuum treatment has become widespread in the aerospace and automotive industries. Vacuum is considered any pressure below atmospheric pressure and can be expressed in torr, micron or millibar in industrial applications. (Figure: Single chamber type vacuum oven and bottom loading)
The effects of component processing in vacuum are twofold:
1. In the medium-high vacuum range the partial pressure of the residual air in the furnace, especially O-HO, is substantially reduced and provides an environment for treating components with little or no surface oxidation. The reduction of the residual nitrogen (N) is also beneficial for the materials, which otherwise would produce nitrides.
2. The decomposition of existing oxides in the surface of the components may occur, depending on the temperature and type of material.
Vacuum furnaces exist in many different mechanical formats, and the models include common components such as:
•Chamber of manufacturing parts or multiple rooms generally with water-cooled shirt, loading and transfer mechanism
•Thermal shields in graphite plate or refractory material
•Charging accessories in graphite plate or refractory material
•Heating element often made of graphite or molybdenum or refractory material for temperatures exceeding 1000 C
•Vacuum pumping system
•Partial pressure control
•Optional fan circulation systems for annealing processes
•Quenching tank and / or gas quenching system / ventilated
The cellular concept of vacuum treatment is becoming more common with the multicellular arrangements used to integrate heat treatment into production and shop fabrication.
If you are cooking a thick slice of steak on a grill or in an oven and you want some pink cooking then you will expect the center of the steak to reach approximately 50 C. Despite this, the 500 C grill or oven will burn the outer part of the steak and the meat will gradually reach a pink cooking in the center of the steak.
Advantages of vacuum cooking can be summarized as follows:
•the hermetically sealed sachet traps the aromas that would normally be lost. So the tastes and flavors are intensified, avoiding the addition of aromatics,
•preservation of vitamins ,
•respect for the product that preserves its tenderness and juicy texture,
•allows better organization and time management in the kitchen,
•the price of cooking equipment (the immersion heater, among others) allowing a very precise control of the temperature are still expensive. Nevertheless, it is still possible to buy at a competitive price temperature controllers coupled with self-cooking rice or cooking sous vide on a stove,
•risk of developing anaerobic flora on the surface of the cooked ingredient,
•cooking under vacuum is not suitable for all foods