How to convert air flow into pressure?

Click For Summary

Discussion Overview

The discussion revolves around the challenge of converting high airflow, low-pressure output from a centrifugal air pump into high-pressure, low-flow output. Participants explore various mechanical and theoretical approaches to achieve this transformation, while also discussing the characteristics and limitations of centrifugal pumps and compressors.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests using a mechanical approach similar to a gearbox to convert high flow, low pressure into high pressure, low flow.
  • Another participant proposes using a valve to reduce flow, which could potentially increase pressure, but requests more details about the pump and system.
  • Clarification is provided that the pump in question is a centrifugal type, which is designed for high airflow but low pressure, suitable for inflating air mattresses.
  • Some participants note that centrifugal compressors can produce high pressure, but the specific pump discussed is not designed for that purpose, emphasizing its performance characteristics.
  • There is mention of electric balloon pumps as a practical alternative for inflating balloons, although this is not the focus of the original question.
  • Discussion includes the performance curve of fans and compressors, indicating that higher flow typically occurs at lower pressure, with a maximum pressure achievable at zero flow.
  • Examples of high-pressure centrifugal compressors are provided, including their use in jet engines and turbochargers, highlighting their design for specific applications.

Areas of Agreement / Disagreement

Participants express differing views on the capabilities of centrifugal pumps and compressors, with some asserting that the specific pump cannot produce high pressure due to its design, while others argue that centrifugal compressors can achieve high pressure under different conditions. The discussion remains unresolved regarding the feasibility of modifying the pump to achieve the desired pressure.

Contextual Notes

Participants note the limitations of the specific centrifugal pump discussed, including its design constraints that prevent it from generating high pressure. The performance characteristics of centrifugal devices are also highlighted, indicating a dependence on their intended use and design parameters.

Artlav
Messages
161
Reaction score
1
Let's say i have an air pump which produce plenty of air flow, but almost no pressure.
Is there a simple way to turn this high flow, low pressure into high pressure, low flow?

I'm thinking something akin to a gearbox turning fast spin, low torque of a motor into a high torque, slow spin output.
Or basically something like a lever - a simple mechanical concentration of force.

I tried putting a cone at the output, but it just reduces the amount of air going out without increasing the pressure.
 
Physics news on Phys.org
Wind turbine -> electricity -> compressor -> any pressure you like.
 
Artlav said:
Let's say i have an air pump which produce plenty of air flow, but almost no pressure.
Is there a simple way to turn this high flow, low pressure into high pressure, low flow?
You describe it as a "pump", which implies that it is a high pressure, low flow device, but then say it is generating high flow and almost no pressure. That doesn't make a lot of sense, but if the flow is higher than you need, you can probably just put a valve on the system to reduce the flow, which will increase the pressure.

But it would help a lot if you provided more details about the pump and the system it is connected to.
I tried putting a cone at the output, but it just reduces the amount of air going out without increasing the pressure.
When you say "output", do you mean output to the air? The output to the air always has to be equal to atmospheric pressure because there is nothing to constrain it.
 
It's a centrifugal "pump" like the image below, used to fill up air mattresses.

It produces a lot of air flow, but almost no pressure.
That is, it can quickly inflate a garbage bag, but won't force any air into a regular party balloon.
The latter is what i was thinking of using it for.

61kzBSjkvFL._SY355_.jpg
 
You can buy electric balloon pumps. They do two balloons at once. Under $40. Perhaps cheaper, I didn't look hard.
 
CWatters said:
You can buy electric balloon pumps.
I know.
But that is not what the question is about.
 
Sorry, but there isn't much that can be done to increase the pressure: it is purposely designed for low pressure so it doesn't pop air mattresses.
 
That is a centrifugal compressor if I'm not wrong. They CANNOT produce high pressure, especially with a gaseous medium.
 
Centrifugal compressors can produce high pressure, but this one isn't designed to. It's more of a blower/fan than a compressor (though the difference is largely colloquia).

Fans, blowers, pumps, compressors, whatever all have a characteristic performance curve whereby higher flow occurs at lower pressure and vice versa (shape is roughly like the upper right quarter of a circle). But there is a maximum pressure that they can achieve at zero flow. The performance curve for this one was purposely selected to provide a maximum pressure that won't pop an air mattress.
 
  • #10
russ_watters said:
Centrifugal compressors can produce high pressure, but this one isn't designed to. It's more of a blower/fan than a compressor (though the difference is largely colloquia).

Fans, blowers, pumps, compressors, whatever all have a characteristic performance curve whereby higher flow occurs at lower pressure and vice versa (shape is roughly like the upper right quarter of a circle). But there is a maximum pressure that they can achieve at zero flow. The performance curve for this one was purposely selected to provide a maximum pressure that won't pop an air mattress.

Well I did not know that. Russ could you give me some examples of high pressure centrifugal compressors. I will appreciate it. Thanx
 
  • #11
Rippetherocker said:
Well I did not know that. Russ could you give me some examples of high pressure centrifugal compressors. I will appreciate it. Thanx

A lot of turboshaft and turboprop jet engines use centrifugal compressors, which will typically give a pressure ratio of something like 5:1 per stage (so a 2 stage centrifugal compressor can give ~25:1, though this depends on the specifics of each design). Wiki actually has a pretty good article on this: http://en.wikipedia.org/wiki/Centrifugal_compressorhttp://en.wikipedia.org/wiki/Centrifugal_compressor EDIT: actually, come to think of it, a high(ish) pressure centrifugal compressor you might be more familiar with also exists in many modern cars - specifically, a turbocharger. They all run centrifugal compressors as well.
 
Last edited by a moderator:

Similar threads

  • · Replies 160 ·
6
Replies
160
Views
11K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 3 ·
Replies
3
Views
8K
  • · Replies 13 ·
Replies
13
Views
6K
  • · Replies 1 ·
Replies
1
Views
5K
  • · Replies 12 ·
Replies
12
Views
4K
  • · Replies 10 ·
Replies
10
Views
4K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 16 ·
Replies
16
Views
3K