Need to use how much air compressor how to calculate the gas flow

find out a core logic

choosing an air compressor is, to put it bluntly, three steps. The first step is to figure out how much gas you need for all your equipment, the second step is to add in the loss and surplus on the pipeline, and the third step is to take this total to find a machine with enough flow.

It sounds simple, but many people are wrong in the first step and it's all for nothing.

The first step is to list all the gas places.

every thing in your factory or workshop that will use compressed air should be listed one by one.

For example, if you have five cylinders working, you should write down how much gas each cylinder needs per minute. Another example is that you have two spray guns. You should also write down how much gas each spray gun uses per minute. What other pneumatic wrenches, atomizers, pneumatic valves, all count.

Add all these numbers together and you get the total demand for your equipment.

Take an example and you will understand. The first cylinder needs ten liters per minute, the second needs eight liters, the third needs twelve liters, and the two spray guns need six liters each, which adds up to ten plus eight plus twelve plus six plus six equals forty-two liters per minute. This is the amount of gas you need to start all your equipment at the same time.

Second step plus loss and margin

the demand for light calculation equipment is not enough, because there is a long air pipe and a bunch of joints from the air compressor to your equipment. These places will leak gas, will consume part of the gas.

Generally speaking, the pipeline loss accounts for about 10% of the total demand. If your pipe is very long, there are many joints, and the pipe is still relatively old, the loss may be greater.

Then leave a safety margin. Because your equipment cannot be running at full capacity all the time, sometimes some equipment is resting, and sometimes suddenly starts at the same time. It is safer to leave a margin of 20% to 30%.

Again with the above example, the equipment demand of 42 litres per minute, plus 10% of the pipeline loss, is more than 46 litres, plus the 25% margin, finally it will take about 58 litres per minute.

This is the air compressor flow you really need.

The third step to choose the machine should pay attention to what

take the calculated number to select the air compressor, the flow rate of the machine must be greater than or equal to this number. However, it should not be too big. Too big wastes electricity and the machine is prone to problems.

When choosing, it depends on whether the machine is free air flow or exhaust flow. The free air flow rate better reflects the real capacity of the machine, and this figure is preferred.

using water to lubricate the air compressor?

if you plan to lubricate the air compressor with water to do this job, the algorithm is the same, but there are a few points to pay attention.

The water-lubricated air compressor uses water instead of oil for lubrication and sealing, so the compressed air it produces does not contain oil. This feature is actually beneficial when calculating traffic.

Because the air produced by the ordinary air compressor will carry oil mist, the oil mist will be blocked when it reaches the filter and dryer behind, causing some gas loss. That is to say, the nominal flow rate of your air compressor may have to be discounted if it can actually reach the gas consumption point.

But the water lubricated air compressor does not have this problem. The gas it comes out is already very clean, and there is almost no need to deal with the oil, so the loss from the air compressor outlet to the gas consumption point will be smaller. You calculate that it needs 58 liters per minute. If you lubricate the air compressor with water, maybe 55 liters per minute is enough.

Of course, this difference is not big, can not completely rely on this to reduce the selection. However, under the same conditions, the actual effective flow of the water-lubricated air compressor is indeed closer to the nominal value than the ordinary machine.

Water lubricated air compressor also has an easily overlooked advantage

when the water-lubricated air compressor is working, the water will take away the heat generated by the compression, the machine runs more smoothly, and the flow output will not be large or small.

This is useful when calculating traffic. Because some machines just start or when the load changes, the flow will fluctuate greatly. If you choose the machine by the peak of the fluctuation, you will choose the big one. However, the flow rate of the water-lubricated air compressor is relatively stable. You can choose according to the average value without leaving too much extra margin.

In this way, the water-lubricated air compressor may save a little selection cost compared with ordinary machines.

A common mistake

many people only count the equipment they are using and forget the equipment that may be added in the future. For example, you have five cylinders now, but you may add two next year. If the machine selected now is just enough, it will have to be replaced next year, which is very wasteful.

Therefore, when calculating the total demand, it is best to take into account the equipment that may be added in the next one to two years. If the air compressor is lubricated with water, because it does not need to change the oil, the maintenance is more worry-free, and the later equipment is easier to adjust.

Another confusing place

flow and pressure are two different things. The flow rate is how much gas is produced per minute, and the pressure is how tight the air pressure is. You are calculating the flow rate, but you must also make sure that the pressure of the machine is enough for your equipment.

These two should be seen together, not without one. Just like when you buy a water pipe, you can't just look at the thickness of the pipe, but also at the water pressure.

To sum up

calculate how much air compressor is needed, just three steps. The first step is to add up the demand for all gas-using equipment, the second step is to add pipeline loss and safety margin, and the third step is to take this total to select a machine with sufficient flow.

If the air compressor is lubricated with water, because the gas it produces does not contain oil, the pipeline loss is smaller, the flow output is more stable, and the actual required machine flow may be slightly smaller than when using an ordinary air compressor. However, no matter what kind of machine is used, the surplus should still be left. Safety first.

If you understand this algorithm, you will never choose the wrong air compressor again.