Below we have tried our best to provide a detailed illustration for conceptual understanding of design, fabrication and operational features of our sturdy built hot air oven.
Design & Construction:
The basic fundamental we keep in mind while designing a laboratory hot air oven is to make it as sturdy and rugged as can be along with being aesthetically appealing. Outer structure of the hot air oven is fabricating using mild steel or stainless steel as per requirement of the client and application of the equipment as mild steel body ovens are suitable for sturdy industrial environments and stainless steel body ovens are more suitable for healthcare, pharmaceutical and similar contamination free zones. The outer body of the oven is made of sheet welded on a tough iron frame suitable for sustaining huge weights at high temperatures. The outer metal sheet body is then painted as per customer requirement using high quality epoxy paints, however high grade stainless steel built bodies are not painted due to their applications in contamination and fumes free zones. Inside the sturdy outer chamber, inner is also built on tough iron frames. After primary construction of the double walled oven body which is designed to achieve minimum heat loss, high grade insulation is inserted in the empty space between the inner and outer chamber of the oven body. The insulation material used is glass wool for ovens till maximum temperature of 250 degree Celsius and mineral wool for insulation in high temperature ovens and furnaces i.e 250 degree Celsius and above. Heating elements used for raising the temperature of the hot air oven are made of high grade kanthal resistance wire which has a good tensile strength for long life. This wire is inserted inside ceramic beads so that it does not come in direct contact of the chamber body and is then placed in proportionate lengths at the bottom and in both the side ribs of the oven for uniform temperature across the chamber.
A Digital Microprocessor based PID Temperature Controller & Display unit is employed to maintain a constant temperature as per the programmed cycle which is also displayed on the seven segment L.E.D display panel. The hot air oven is mounted on four rubber feet to prevent it from slipping and this protects the bench surface too. In some applications where mobile hot air oven units are required, small bearing enabled wheels are placed instead of rubber feat. The control panel is installed with a main ON/OFF switch, LOAD ON/OFF Indicator lamps and a digital microprocessor based PID Temperature Controller come display unit. Being in a constant approach to upgrade the designs of our equipment we have also introduced data logging facility in our hot air oven. As all add on features come with an extra cost the data logger controller is not part of the standard equipment and is added on special orders only.
The basic Working Principle of Hot Air Oven:is the forced circulation of hot air inside the chamber of oven. Although scientifically speaking a hot air oven is designed by applying the combined theories of thermal convection and also thermal radiation during an operation cycle. It is a scientifically proven phenomenon of thermal convection that in any given chamber hot air rises because of molecular expansion happening by infusion of thermal energy in it causing molecular displacement and forcing the downward displacement of denser cold air. So by utilizing this principle when the hot air reaches the top of chamber it is rapidly circulated back to bottom by a fan installed inside the chamber and hence optimum amount of heat is achieved gradually inside all the corners of Hot Air Oven.
Uses of Hot Air Oven can be described as below:
Various Types and Sizes of Hot Air Oven include: • In R&D centers & institutions for research and development purposes.
• For sample testing and product evaluation in industries using tests like aging, compression set, heat deformation and temperature resistance.
• In hospitals and health centers for various applications such as heating, drying & sterilizing.
Most Common Types and Sizes of Hot Air Oven used in testing & research labs are:
• Outer MS/SS, Inner SS grade 316 (12x12x12)inches, (300x300x300)mm.
• Outer MS/SS, Inner SS grade 316 (18x18x18)inches, (450x450x450)mm.
• Outer MS/SS, Inner SS grade 316 (24x24x24)inches, (600x600x600)mm.
• Outer MS/SS, Inner SS grade 316 (24x36x36)inches, (600x900x900)mm.
*the sizes mentioned above are of inner chamber.