Vacuum ovens are commonly used for drying samples at the lowest possible temperature to avoid deterioration of the sample. Beyond sample drying, vacuum ovens are used for applications such as curing epoxies, baking-out, degassing liquids, moisture determination, aging tests, and heat treating. Vacuum pump selection depends on the oven volume, the chemistry of the vapors removed from oven, vacuum level needed for process, and the mass of those vapors removed.
For many procedures using vacuum ovens, an oil-free, standard duty, WOB-L piston vacuum pump or a chemical duty diaphragm vacuum pump offer a sufficient vacuum level to do the job. These are compact, lightweight and portable vacuum pumps. Because the vacuum pumps are oil-free, there is no oil contamination of samples, no exhaust smoke, no oil leaks, and best of all, no oil changes. Normally a liquid trap is located in front of the vacuum pump to avoid any vapor that condenses within the vacuum line from being drawn into the vacuum pump. Supplemental inlet cold traps are recommended for high water vapor loads.
Some applications for vacuum ovens require sample drying, bake-out, curing, etc. require ultimate vacuum pressure below 0.1 torr (0.13 mbar). In these situations, the key factor in vacuum pump selection is in the ultimate vacuum level achievable by the pumps. Welch Vacuum offers vacuum pump solutions for this high vacuum level in oil-free and oil-sealed vacuum pump technologies. Your individual budget requirements play a key role in deciding what type of pumping technology should be selected.