Request a free sample of our products - contact us at 1-855-208-2005

Frequently Asked Questions

How do diffusion pumps work?

How do diffusion pumps work?

Diffusion pumps work by heating an oil with low vapor pressure, at the moment, most operators are using silicone based diffusion pump oils. The escaping vapors are funneled into downward pointing pressure jets. As the vapors exit at high speeds, sometimes breaking the sound barrier, air molecules are trapped and forced downwards. Learn more about how diffusion pumps work. Can diffusion pump oil be reused?

Can diffusion pump oil be reused?

No. Diffusion pump oil cannot be reused. While it may sound like a good option to filter the impurities out of used pump oil and introduce it back into the system, this will not improve its performance. This is because the high temperature and pressure has already destroyed the oil on a molecular level, filtration will not fix this. Should I use hydrocarbon or silicone based diffusion pump oil?

Should I use hydrocarbon or silicone based diffusion pump oil?

Under normal circumstances, it is better to use silicone based diffusion pump oil over hydrocarbon based ones. While this is so, there are circumstances where hydrocarbon based oils should be considered (read the linked article). What is the shelf life of diffusion pump oil?

What is the shelf life of diffusion pump oil?

Approximately 2 years. When should I check the level of diffusion pump oil?

When should I check the level of diffusion pump oil?

You should check the levels of diffusion pump oil routinely and only when the pump has returned to room temperature. Why should I check the level of diffusion pump oil?

Why should I check the level of diffusion pump oil?

As diffusion pump oil is heated, small amounts of oil vapors will escape the system. Therefore, as you operate the diffusion pump, you will lose oil due to leakage. The rate of decrease will depend on several factors including the temperature used, the presence of leaks, whether you're using a cold cap or baffle, and more. Basically, as the temperature applied remains constant where the volume oil decreases, this will lead to overheating of the decreasing oil which in turn will lead to faster oil loss, lowering vacuum, and possible damage to your diffusion pump in more extreme cases. Therefore, we suggest always keeping an eye on your oil levels and top off when necessary. When should I change the diffusion pump oil?

When should I change the diffusion pump oil?

If you're using hydrocarbon based diffusion pump oil, it should be changed approximately every 3-6 months. If you're using silicone based diffusion pump oil, you generally do not need to replace the oil for at least 12-18 months. Make sure you're topping off the oil and change the oil based on actual conditions. For example, for applications where the oil is easily contaminated, you may need to replace the oil more frequently. For more information, check out the diffusion pump maintenance guide. Does my diffusion pump require a special type of diffusion pump oil?

Does my diffusion pump require a special type of diffusion pump oil?

No. It doesn't matter where your diffusion pump is manufactured or what brand it is, diffusion pumps need diffusion pump oil to operate whether you choose hydrocarbon or silicone based oils. If you're not using our brand of diffusion pump oil, make sure you're using high quality oil from a reputable company. Where can I purchase DC-702, DC-704, or DC-705?

Where can I purchase DC-702, DC-704, or DC-705?

These are no longer available since Dow Croning stopped manufacturing diffusion pump oil all together in 2012. We do, however, offer the perfect replacement; ECO-702, EN-704, and EN-705. Which model of diffusion pump oil should I use?

Which model of diffusion pump oil should I use?

It really depends on your required vacuum pressure:
Require Vacuum Pressure Diffusion Pump Oil Used
10-5 to 10-6 Torr ECO-702
10-7 to 10-8 Torr ECO-704
10-9 to 10-10 Torr ECO-705
What is the optimal temperature for my diffusion pump?

What is the optimal temperature for my diffusion pump?

This will depend on the type of oil you're using, please see chart below:
Diffusion Pump Oil Used Recommended Temperature
ECO-702 180-190 °C
ECO-704 220-230 °C
ECO-705 245-255 °C
Do I need to clean my diffusion pump every time I change the oil?

Do I need to clean my diffusion pump every time I change the oil?

If you're using hydrocarbon based diffusion pump oil, yes, you'll need to disassemble your diffusion pump and wash with a solvent every time the oil is changed. If you're using silicone based diffusion pump oil, no, just drain the oil and add in the new one. Generally speaking, you'll only need to disassemble and clean the diffusion pump every 2-3 years. Can I mix different types of diffusion pump oil?

Can I mix different types of diffusion pump oil?

No. Do not mix hydrocarbon based diffusion pump oil with silicone based ones. Additionally, do not mix the varying models. That is, EN-702, EN-704, and EN-705 should not be mixed together as although they are silicone based, they are very different. How can I extend the life cycle of diffusion pump oil?

How can I extend the life cycle of diffusion pump oil?

As the diffusion pump oil is the most expensive part of using a diffusion pump, you need to make sure your entire system is running optimally and that oil is not unnecessarily lost. See our tips on increasing the life cycle of diffusion pump oil.