Proper Cleaning of Vacuum Components

Clean surfaces are a must-have when dealing with a vacuum system and its accompanying technology. There’s a need to ensure that all impurities get removed from its surfaces. Their removal guarantees that they won’t desorb when exposed to vacuum conditions.

If desorbed, they may accumulate on the vacuum pump or other similar components. In some cases, they could also produce gases that pollute the surrounding environment, making it difficult to breathe.

Pre-Treatment of UHV Systems

High Vac Depot recommends that proper cleaning of a vacuum system begins with pre-treatment. For example, you can pretreat the components using a high-pressure cleaner which comes in handy in removing coarse dirt on the pump’s surface.

Pre-treatment helps pave the way for the actual cleaning of these components.

What’s the Standard Approach Used when Cleaning a Vacuum Pump?

Tons of contaminants can affect the components used in a vacuum system. When you look at the metal parts, for instance, the pollutants can include:

• Coolants employed during the machining process
• Cutting fluids
• Improper storage of the system
• Handling by humans

It’s possible to mitigate a number of these through basic, multi-step cleaning procedures. Deploying proper protection techniques to protect the pump and the system from the contaminants present in the environment can also help.

As noted above, humans are among the most prevalent sources of contamination for vacuum components and systems. For example,

1. Did you know that your eyebrows are filled with dust mites?
2. Or that your body sheds up to 600,000 skin cells every sixty minutes?
3. Or that you lose an average of 150 hairs on any given day?

Furthermore, every time you open your mouth to speak, you normally end up spitting. Other sources of contamination in a system include your handprint, which contains close to 1019 molecules.

Therefore, before any cleaning can happen, the first thing to do is to protect the part you want to clean. High Vac Depot recommends wearing fitting gloves. The outer areas of the gloves shouldn’t come into contact with any part of your body.

Apart from gloves, the next protective item you’ll need is a mask. The masks ensure that the spit from your mouth won’t land on any of the components lined up before you for cleaning when you speak.

Fortunately, it’s possible to remove the contaminants from humans and the environment following a series of steps. Ensuring you follow these steps as outlined is the only way to guarantee that you’ll leave the vacuum pump cleaner than it was before.

The steps outlined below work for most metal components that make up a vacuum system:

• Use an organic solvent to remove any hydrocarbons present in the system
• Use soap and water to remove contaminants that readily dissolve in water
• Use water to remove the soap used above
• Use alcohol to remove the water
• Use hot, dry air to remove traces of the alcohol (the air should preferably have a temperature of around 120oF to ensure your safety.)
• Allow the part sufficient time to cool down before using the appropriate containment to secure it.

You have several options when it comes to organic solvents. Consider using anything that’s miscible in water, e.g., methanol or ethanol. The solvent you choose shouldn’t prove harmful to the environment or the humans using it.

For the step involving water and soap, you can go for something simple and readily available, e.g., tap water or dishwashing liquid. Fancier cleaning items such as deionized or distilled water could also work.

When the time comes to remove the “soap and water,” make sure to use deionized or distilled water. Opt for +99% pure isopropanol or electronic grade alcohol. Use a commercial heat gun capable of delivering a +120oF air stream to remove the alcohol. Please refrain from using a hair drier to remove the alcohol. The commercial heat gun will ensure that you’re safe and that the parts don’t become too hot that you can’t handle them with ease. Place the cleaned vacuum system component on a clean cloth free of any lint to cool down.

For parts that you don’t intend to use on the system immediately after cleaning, make sure to use a clean, lint-free cloth to wrap them. Once bound, the pump or other vacuum component should go inside a zip-locked bag for storage purposes. It should remain in the bag until it is needed for use.

Although the now clean part will have absorbed some of the cleaning water onto its surfaces, much of this will go away once it’s put back into the system. It typically takes around 4 – 10 hours of high-pressure levels of about 10-7 Torr to absorb all the water.

Summary of the Cleaning Process

• The initial cleaning of a vacuum pump occurs under ultrasonic conditions. It involves the addition of special cleaners that assists in cleaning and degreasing the surface of the pump.
• All contaminants present on the pump get lifted and bound from it using a specially prepared cleaning bath.
• The cleaner must ensure that they adjust the pH levels of the cleaning bath to ensure that it matches that of the chamber material.
• The cleaner will use pre-rinsing to remove the detergent in the subsequent baths and follow this up with a deionized water rinse.
• Rinsing should be followed by drying, which must happen using dust-free and hydrocarbon-free air.
• In the case of large chambers, the cleaner will need to use high-pressure cleaners or steam to clean them. They may need to add some special cleaning agents.
• The cleaner will need to use deionized water several times to clean the chamber before using hot air to dry it.

Verification of Cleanliness

According to the High Vac Depot vacuum technologist, verifying chamber or vacuum system cleanliness is another issue. After cleaning, there’s a need to check whether the pumps can attain their base pressure.

If they do, the vacuum chamber and its attachments are considered clean. Another way to confirm cleanliness is by scanning the partial gas pressures each part may be emitting.

A clean system should only emit a signature that includes carbon dioxide, hydrogen, nitrogen, and water. It shouldn’t have any other signature in it.