# How to convert air flow into pressure?

• Artlav
In summary, the conversation discusses the use of an air pump that produces high flow but low pressure. The question arises if there is a simple way to turn this high flow, low pressure into high pressure, low flow. Suggestions are given such as using a gearbox or lever, but it is ultimately determined that the pump is designed for low pressure and cannot be easily converted. Examples of high pressure centrifugal compressors are given, such as those used in jet engines and modern cars. It is also noted that many commercial and industrial applications use centrifugal compressors for high volume air flow.
Artlav
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.

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.

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.

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

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.

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## 1. How is air flow converted into pressure?

Air flow can be converted into pressure through the use of a device called a Venturi tube. This device has a constriction in the middle which causes the air flow to speed up, creating a decrease in pressure. The decrease in pressure can then be measured and converted into a pressure reading.

## 2. What is the relationship between air flow and pressure?

The relationship between air flow and pressure is known as Bernoulli's principle. This principle states that as the speed of a fluid (such as air) increases, the pressure decreases. This means that as air flow increases, the pressure decreases and vice versa.

## 3. What factors affect the conversion of air flow into pressure?

The conversion of air flow into pressure can be affected by several factors, including the shape of the Venturi tube, the diameter of the constriction, and the viscosity of the fluid. The temperature and humidity of the air can also play a role in the conversion process.

## 4. How accurate is the conversion of air flow into pressure?

The accuracy of the conversion of air flow into pressure depends on the precision of the measuring instrument used, as well as the conditions in which the conversion is taking place. It is important to use calibrated instruments and to account for any external factors that may affect the accuracy of the measurement.

## 5. Can air flow be converted into pressure without the use of a Venturi tube?

While the Venturi tube is the most common method for converting air flow into pressure, there are other devices and techniques that can be used. These include pitot tubes, orifice plates, and flow nozzles. Each method has its own advantages and limitations, and the best option will depend on the specific application and requirements.

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