Research on Vacuum Pumps

[Elizabeth111]

Hello,

I am currently reseaching the uses of vacuum pumps in labs, different types of vacuum pumps used in labs and their applications. If there is anyone that works in these environments please reach out as your information will help me out immensley.

[exchemist]

3 hours ago, Elizabeth111 said:

Hello,

I am currently reseaching the uses of vacuum pumps in labs, different types of vacuum pumps used in labs and their applications. If there is anyone that works in these environments please reach out as your information will help me out immensley.

I'm terribly out of date I'm afraid, as I have not used a vacuum line since my university research, over 40 years ago.

I recall being impressed with the mercury diffusion pump, though it was a bastard if any gas got past the liquid N2 trap and reacted with the mercury. I had some trouble with nitric oxide, if I remember correctly.   

[swansont]

We have used ion pumps for our clocks since we wanted what is ultimately an oil-free system for long-term operation, though we use a turbo + mechanical pump to get down to the pressure where the ion pump will start.

I used a diffusion pump in grad school. Luckily it never vented to air while operating, so I never had to clean up the resulting mess. I put various interlocks in place to shut pneumatically-operated gate valves in case it was exposed to higher pressures (like if there was a serious leak) and shut things down if the pump cooling was interrupted.

[Elizabeth111]

23 hours ago, swansont said:

We have used ion pumps for our clocks since we wanted what is ultimately an oil-free system for long-term operation, though we use a turbo + mechanical pump to get down to the pressure where the ion pump will start.

I used a diffusion pump in grad school. Luckily it never vented to air while operating, so I never had to clean up the resulting mess. I put various interlocks in place to shut pneumatically-operated gate valves in case it was exposed to higher pressures (like if there was a serious leak) and shut things down if the pump cooling was interrupted.

Hi, thanks for replying.

Could you elaborate on what you meant by clocks? How did the use of the ion pumps help with what you were investigating?

Additionally, do you know the application the ion pump used? Was there any special requirements that the pump needed?

On 8/1/2022 at 8:45 PM, exchemist said:

I'm terribly out of date I'm afraid, as I have not used a vacuum line since my university research, over 40 years ago.

I recall being impressed with the mercury diffusion pump, though it was a bastard if any gas got past the liquid N2 trap and reacted with the mercury. I had some trouble with nitric oxide, if I remember correctly.   

Wow, you were working with some really serious stuff. It's interesting to see how technology has improved since then. Thanks for replying.

[swansont]

1 hour ago, Elizabeth111 said:

Hi, thanks for replying.

Could you elaborate on what you meant by clocks?

Atomic fountain clock. 

1 hour ago, Elizabeth111 said:

How did the use of the ion pumps help with what you were investigating?

To reduce scattering with background gases, the device is run under high vacuum.

 

1 hour ago, Elizabeth111 said:

Additionally, do you know the application the ion pump used? Was there any special requirements that the pump needed?

It attaches to a controller which provides the high voltage needed and measures the pressure.

 

[KyleLeClair]

Here's a useful tree diagram of the different vacuum pumps technologies used in a lab environment. I retrieved it from Vacuum Science World. It's a good thing to keep around. 

When I decide what pumps should be implemented I go through a thought process that ask the following questions..

1. Is the experiment feasible at my price range? (Torr 10^(-?) vs Cost)
2. Can I risk or mitigate oil contamination?
3. What's my primary? > Roughing Stage
4. What's my secondary? > High Vacuum Stage
5. What gas is being inserted or removed from the chamber?
   1. Can heat producing capture methods be used?
   2. Does residual gas need to be removed?
   3. What reactivity does the inserted gas have? Inert or reactive?
6. What is my capture? > Sustainment Stage
7. Is there any safety devices I need? (reverse flow media restrictor, flame arrestors, etc)

You can look into the nomenclature and theory of operation of all these pumps, some are very interesting. 

Also, the textbook Building Scientific Apparatus By John H. Moore (ISBN:0521878586) has tons of fantastic information regarding UHV chambers, glass blowing, system design, pump design, etc. I recommend adding it to the bookshelf.