Best vac pump for boiling water

In summary, the author is looking for advice on the best vacuum pump to move water vapor up to a higher pressure. They have tried a few pumps, but none of them are low enough in ultimate pressure. They are considering a liquid ring vacuum pump, but they are not sure if they are able to build or purchase one.
  • #1
krysith
23
0
Hello all,

I am seeking advice on the best, relatively cheap vacuum pump to pump water vapor from the 2 kPa range to the 100 kPa range. Essentially any pump that would work well at boiling water at room temperature would work for me. I'm hoping that someone on here may have done that as a demonstration and may have some practical advice for me.

What I want is to move the water vapor somewhere, not to generate a vacuum, so getters, pre-pump cold traps, etc. aren't really helpful. I need to actually pump the water vapor to a higher pressure location.

I have tried a few pumps I have on hand. I have a little Gast pump that's great and reliable, but it doesn't have a low enough ultimate pressure. I tried hooking up two Gast pumps in series, but apparently too much air leaks through the piston seals and they still don't have a low enough ultimate pressure.

I also tried a good old fashioned rotary vane roughing pump. This has (or had) a low enough ultimate pressure. However, I have found that condensing water inside the pump is not good for it. It no longer runs, although I could repair it if it would be useful.

I was thinking that the biggest problem was that water was recondensing inside the pump. However, I don't know of any pump that could operate at a high enough temperature to keep the water vapor from recondensing. Most pumps will kick out the temperature switches on their motors long before getting that hot. Perhaps some belt-run Welch pumps?

I've considered a liquid ring vacuum pump, using a liquid with a lower vapor pressure than water. This seems to be just the right thing. Unfortunately, these seem to be only available in large, expensive commercial versions. I have tried building my own, and frankly while I have rebuilt vacuum pumps before, building one from scratch may be beyond me. Since building one or spending $8000+ on a commercial one seem to be my only options, I'm reaching a point of frustration on this project. I'm self-financing this. Can anyone help?

If this is not the correct sub-forum for this question please move it.
 
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  • #2
Could a mod, mentor, or admin please move this post to a sub-forum where it is more likely to receive a reply? Thank you
 
Last edited:

1. What is the best type of vacuum pump for boiling water?

The best type of vacuum pump for boiling water is a rotary vane pump. This type of pump is specifically designed for handling liquids and can withstand high temperatures. It also has a high pumping speed and is able to create a strong vacuum.

2. What is the ideal vacuum level for boiling water?

The ideal vacuum level for boiling water is around 29 inches of mercury (Hg). This is equivalent to 760 millimeters of mercury (mmHg) or 101.3 kilopascals (kPa). This level of vacuum will allow the water to boil at a lower temperature, making it more energy efficient and reducing the risk of over-boiling.

3. Can any vacuum pump be used for boiling water?

No, not all vacuum pumps are suitable for boiling water. It is important to choose a pump that is specifically designed for handling liquids and can withstand high temperatures. Using the wrong type of pump can lead to damage or malfunction.

4. How do I maintain a vacuum pump for boiling water?

To maintain a vacuum pump for boiling water, it is important to regularly clean and change the oil. This will help keep the pump running smoothly and prevent any buildup or contamination. It is also important to follow the manufacturer's instructions for maintenance and replace any worn or damaged parts as needed.

5. Are there any safety precautions I should take when using a vacuum pump for boiling water?

Yes, there are a few safety precautions to keep in mind when using a vacuum pump for boiling water. Make sure to wear appropriate protective gear, such as heat-resistant gloves and goggles, when handling hot water or operating the pump. It is also important to follow proper procedures for starting and stopping the pump to prevent any accidents or injuries.

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