Using the right vacuum pump with your vacuum oven is important to ensure reliable operation and rapid, effective drying. However, simply hooking up the pump to the oven isn't sufficient to ensure that your operations are trouble-free and your equipment lasts as long as possible. There are a number of things you should know about this application.
One crucial thing to remember is that vacuum ovens must be placed under vacuum prior to heating for several important reasons.
- If the liquid material is heated first, the gas will expand. Unlike convection ovens (and almost all other ovens), vacuum ovens do not vent at all and are completely air-tight. Therefore, evaporation will cause pressure from the expanding gases to build. In the event of an issue with the pressure release value, this could potentially cause the tempered glass of the viewing window to burst.
- The heated gas could also reach the vacuum pressure gauge, causing a temperature increase. If this rise exceeds the gauge's specified operating range, which is often relatively narrow, it may result in misreadings.
- Heating the oven before the commencement of pumping could transfer the heat to the vacuum pump, causing its temperature to rise and lowering the pump's efficiency.
In summary, the correct procedure is to evacuate first and then heat. If the vacuum level drops after reaching the desired temperature, evacuate again for a short while. This practice will help prolong the lifespan of your industrial vacuum oven.
Two Across International Vacuum Ovens with vacuum pumps on a mobile support table.
Here are some handy tips to get the most out of your equipment, including routine maintenance and proper usage techniques to keep it running smoothly for a long time.
- Choose vacuum pumps with the right capacity for your needs. For most wet applications, rotary vane and diaphragm pumps are your best bet because they are reliable and efficient. Do not use aspirators.
- Make sure your equipment can handle the required vacuum level.
- Adhere to the manufacturer's maintenance recommendations, such as regular oil changes (when applicable) and routine inspections, to ensure your equipment operates efficiently. Change oil when it begins to darken or turns opaque.
Dos and Don'ts with Vacuum Pumps.
Do's
- Use only in areas specified in the operating manual. It's crucial to avoid operating pumps in poorly ventilated spaces, as this can cause harmful fumes to accumulate and reduce equipment efficiency. To ensure safety, optimal performance, and prevent overheating, the area should be well ventilated.
- Handle gases only as described in its manual. Using the pump for gases not listed in the manual could lead to damage or unsafe operating conditions.
- Keep track of all pump maintenance.
- If the pump is an oil functioning one, the pump oil must be appropriate and compatible with vapors that will pass through.
- Make sure to maintain oil mist separators as per the manufacturer’s instructions. If these units get clogged, especially when using old pump oil, they can fail catastrophically.
- Put the pump on a tray to catch any spilled oil. Use some absorbent pads to soak up any extra oil. Remember, both the oil and the soaked pads need to be treated as hazardous waste.
- When using a vacuum with hazardous biological materials, make sure to use a liquid trap with an appropriate disinfectant.
- If an oil-free pump shows signs of vapor leakage (condensed liquid around the outlet), add a cold trap upstream of the vacuum pump to prevent damage to the pump or otherwise change the process to prevent significant quantities of vapor from reaching the pump.
Don'ts
- Do not operate if it is only partially assembled. Ensuring the pump is fully assembled before operation is essential to prevent malfunctions and potential hazards.
- Do not place it in an enclosed, unventilated, or poorly ventilated cabinet. Proper ventilation is necessary to avoid overheating and to maintain optimal performance.
- Do not use solvents that could damage the pump unless you have a proper trap in place.
- Never allow a vacuum pump to draw liquid into it. Flooding a vacuum pump could damage it and is almost never covered under warranty.
Important! In addition, please follow your region’s current accident prevention, safety and operating regulations, as enforced by law. This guide provides some tips on safely operating vacuum pumps. It’s not exhaustive and doesn’t aim to perfectly interpret current safety laws. Also, keep in mind the unique features and various uses of different products.
References:
https://ehs.umass.edu/sites/default/files/Vacuum%20pumps%20SOP_0.pdf
