Piston suction pump versus external gear pump as vacuum pump

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SUMMARY

The discussion centers on the effectiveness of piston suction pumps compared to external gear pumps as vacuum pumps. Participants conclude that piston suction pumps are superior due to their ability to create a higher vacuum and lower leakage rates. Eccentric vane pumps are also mentioned as a top choice for vacuum applications, outperforming both piston and gear pumps. The conversation highlights the importance of application-specific pump selection, emphasizing that while piston pumps excel in vacuum generation, external gear pumps are generally unsuitable for such tasks.

PREREQUISITES
  • Understanding of vacuum pump types: piston suction pumps, external gear pumps, and eccentric vane pumps.
  • Knowledge of vacuum principles and pressure measurement (Torr).
  • Familiarity with pump applications and their specific use cases.
  • Basic mechanical engineering concepts related to pump design and operation.
NEXT STEPS
  • Research the operational principles of eccentric vane pumps and their applications in vacuum systems.
  • Explore the design and functionality of rotary lobe pumps and their effectiveness in various scenarios.
  • Study the impact of leakage in vacuum systems and methods to minimize it.
  • Investigate the requirements for constructing a DIY vacuum pump and the materials involved.
USEFUL FOR

This discussion is beneficial for engineers, DIY enthusiasts, and anyone involved in selecting or designing vacuum systems, particularly those comparing different pump technologies for specific applications.

  • #31
Averagesupernova said:
What do you think? Have you thought about the pressures on each side? And have you thought about how it will be built to withstand those pressures and what it takes to seal the joints?

We will need to weld any openings if the container is a steel container. Is there a shape that is more appropriate than cube?
 
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  • #32
I'll ask it again:

Averagesupernova said:
Have you thought about the pressures on each side?
 
  • #33
The best vacuum pump depends on your needs. You need to specify two things - the amount of vacuum and the flow rate before we can give you useful advice.

Amount of vacuum could be, for example: 1 inch of water, 20 inches of mercury, 10 torr, 1 torr, 1 millitorr, or other. You need to specify the amount, and know why you want that much vacuum. You need to know how much vacuum you need because higher vacuums cost more.

Flow rate: When evacuating a vessel, this could be as simple as specifying that you want to reach that vacuum in 1 second, 1 minute, 1 hour, or 1 day. You need to specify the volume subject to the vacuum, and the time to get to that vacuum. You need know what flow rate you need because higher flow rates cost more.

We need real numbers to help you with your vacuum pump. And real numbers to help you with your vacuum vessel.
 
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  • #34
If you are just comparing pumps to see which can achieve the highest vacuum I don't see why you even need a vacuum vessel. A hose with a gauge on the end will suffice. This whole thing stinks of you trying to hide what you are doing. Now the question is what is it that you are really doing that is against forum rules so you need to hide it? Or are you simply that uninformed so you do not realize what you do and do not need for this?
 
  • #35
johnthekid said:
Even if both are designed as simple as possible? Now I'm curious about the Torr range that a piston pump with pressure operated check valves and an external gear pump can produce.
The piston pump valve requires a pressure difference to lift it. That pressure drop reduces the depth of the vacuum that can be pulled.

Vane and gear pumps do not have valves. The ports open and close based on the position of the vane, or the gear tooth.
 
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  • #36
jrmichler said:
The best vacuum pump depends on your needs. You need to specify two things - the amount of vacuum and the flow rate before we can give you useful advice.

Amount of vacuum could be, for example: 1 inch of water, 20 inches of mercury, 10 torr, 1 torr, 1 millitorr, or other. You need to specify the amount, and know why you want that much vacuum. You need to know how much vacuum you need because higher vacuums cost more.

Flow rate: When evacuating a vessel, this could be as simple as specifying that you want to reach that vacuum in 1 second, 1 minute, 1 hour, or 1 day. You need to specify the volume subject to the vacuum, and the time to get to that vacuum. You need know what flow rate you need because higher flow rates cost more.

We need real numbers to help you with your vacuum pump. And real numbers to help you with your vacuum vessel.

Around 1 Torr I think is enough. Anything above 1 Torr we need more cost. Is fast evacuation or higher flow rate equals to better vacuum pump? What I'm trying to do is just fun experiment.
 
  • #37
Averagesupernova said:
I'll ask it again:

Averagesupernova said:
If you are just comparing pumps to see which can achieve the highest vacuum I don't see why you even need a vacuum vessel. A hose with a gauge on the end will suffice. This whole thing stinks of you trying to hide what you are doing. Now the question is what is it that you are really doing that is against forum rules so you need to hide it? Or are you simply that uninformed so you do not realize what you do and do not need for this?

I don't have enough experience to understand the details so please tell me more. Sorry, hiding what? Yes, if without using a vacuum vessel means cost saving, we don't have to use sophisticated setup like requiring vacuum vessels, etc.
 
  • #38
Baluncore said:
The piston pump valve requires a pressure difference to lift it. That pressure drop reduces the depth of the vacuum that can be pulled.

Vane and gear pumps do not have valves. The ports open and close based on the position of the vane, or the gear tooth.

Gotcha. Thank you so much.
 
  • #39
Baluncore said:
The piston pump valve requires a pressure difference to lift it. That pressure drop reduces the depth of the vacuum that can be pulled.

Vane and gear pumps do not have valves. The ports open and close based on the position of the vane, or the gear tooth.

Where can I get more understandings regarding the comparison between different types of vacuum pumps in their effectiveness in generating lower pressure vacuum especially when used independently on their own?
 
  • #40
johnthekid said:
Where can I get more understandings regarding the comparison between different types of vacuum pumps in their effectiveness in generating lower pressure vacuum, especially when used independently on their own?
It takes time, you cannot get that understanding quickly. Start by following every relevant link on Wikipedia and look at the references given there. Let the information and ideas soak into your brain, then organise them over time, into reliable concepts.

For each project, write a technical specification, so you know precisely what is required. Then look for reliable solutions, at the lowest cost. Keep working in that field for 10 years.

It takes time to assemble and understand the deeper concepts. It takes engineering to analyse how and why pumps do, or don't work, and their limitations. Study engineering.

Search libraries such as:
https://z-library.sk/s/vacuum pumps
https://z-library.sk/s/vacuum systems
 
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  • #41
Baluncore said:
It takes time, you cannot get that understanding quickly. Start by following every relevant link on Wikipedia and look at the references given there. Let the information and ideas soak into your brain, then organise them over time, into reliable concepts.

For each project, write a technical specification, so you know precisely what is required. Then look for reliable solutions, at the lowest cost. Keep working in that field for 10 years.

It takes time to assemble and understand the deeper concepts. It takes engineering to analyse how and why pumps do, or don't work, and their limitations. Study engineering.

Search libraries such as:
https://z-library.sk/s/vacuum pumps
https://z-library.sk/s/vacuum systems

Cheers 👍👍
 

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