Almost all compressor manuals that have compressed air output information provide it at 90 PSI and sometimes at 40 PSI. Knowing the air compressor output at 90 PSI output is good, since many air tools are rated on their air consumption at that pressure. How to calculate CFM of air compressors? CFM vs PSI – Air Volume vs Pressure. The CFM at the air compressor outlet will increase if you reduce the outlet PSI.The CFM at the air compressor outlet will decrease if you increase the outlet PSI.The exact mathematical relationship between CFM versus PSI has lots of noise factors. Air Tank Outlet CFM to PSI vs Air Compressor Pump PSI to CFM. However let’s ignore the Air Compressor PUMP for a moment and JUST concentrate on the compressed air TANK. If a compressed air TANK has a regulator attached to it which is set to 90 PSI and the air in the tank is always kept between 90-130 PSI – lets say that the CONTINUOUS CFM out of the regulator is equal to “x”. If you then adjust the air pressure regulator to 45 PSI and the air in the tank is once again always kept between 90-130 PSI. The CONTINUOUS CFM out of the regulator is now = 2*x. This approximation is SOUND. REGARDLESS of what the CFM of the Air Compressor PUMP is. The above scenario DOES however rely on the fact that the air compressor PUMP has an AVERAGE CFM of ABOVE x when replenishing air into the air tank at 90-130 PSI. So to summarise the cubic feet per minute to psi question – it depends highly on where you’re measuring. The CFM demand at 90 PSI in the above example is less than the stated CFM of the compressor at 90 PSI. This is because the air compressor TANK decouples the CFM rating of the air compressor PUMP from the CFM flowing out of the air pressure regulator. Electric air compressor has 6.8 CFM at 40 PSI, and 5.1 CFM at 90 PSI, but I’d like to know what CFM it has at 23 PSI to utilize a DeVilbiss Finishline 4 HVLP paint gun, which requires a minimum of 13 CFM at that PSI to run properly.
This indicates the complexity of the relationship between CFM and PSI. Air Tank Outlet and Pump Relationship Between CFM & PSI. Let’s focus on the air tank first. If the air compressor tank has a regulator attached to is set to 90 PSI while the air tank itself is always kept within 90-120 PSI. We’ll label the continuous CFM out of the regulator as “x”. If we were to adjust the pressure at the regulator to 30 PSI and the air in the tank is still kept between 90-120 PSI then the continuous CFM out of the regulator is equal to 3*”x”, approximately! This scenario relies on the fact that the air compressor pump has an average CFM above “x” when replenishing the air into the tank at 90-120 PSI. The relationship between CFM & PSI depends highly on where you’re measuring it. This is because each pump will have its mechanical configuration to operate at specific ranges of PSI and CFM. Therefore, it is the air compressor tank outlet CFM and PSI relationship that really matters to users. The CFM and PSI at the outlet of the air compressor tank/regulator have no relationship with the CFM and PSI relationship in the air compressor pump if the CFM of the compressor is below its stated amount of 90 PSI. The reason behind this is simple, the air compressor tank decouples the CFM of the air compressor pump from the CFM flowing out of the air compressor regulator. If your tools require 10 CFM then your air compressor must be at least 20 CFM. This is based on the assumption that the average rating of CFM considers a 50% duty cycle. If you have any questions regarding calculating the CFM of an air compressor outlet and pump, please leave a comment below, with a photo if applicable, so that someone can help you!
Learn what you need to keep your air compressor equipment running efficiently with Lewis Systems easy-to-use air compressor calculations and formulas tool. CFM of compressed air required to raise a known system pressure to a desired system pressure:C2 = Required CFM total.
how to calculate cfm of air compressor pdf Related Question:
How do you calculate CFM?
CFM = (fpm * area), where fpm is the feet per minute. To find the cubic feet per minute, substitute the FPM value with the area after the area is squared.
What is CFM on a compressor?
CFM stands for cubic feet per minute. This is the air flow or air volume that a compressor can supply – or its output. Many pneumatic power tools require a CFM of about 5, but it really varies. A pneumatic stapler might just need 0.3 CFM, while a framing nailer may require 2.2 CFM.
How do you calculate capacity of a compressor?
Eg: CFM (Cubic Feet per Minute) – Cubic Feet is a unit of volume and minutes is a unit of time. 1 cubic foot is = 28.317 Liters. Therefore 1 CFM = 28.31 (LPM) Liters Per Minute. Similarly Liters per Second (L/sec) or Cubic Meter per hour are units of flow of air.
How do you calculate fresh air CFM?
Next, to find the fresh cfm, multiply the percentage of fresh air by the fan airflow. Let’s say we have a 3-ton system moving 1,200 cfm. Multiply the 20% fresh air by the 1,200 cfm to find a fresh air cfm of 240.
What is CFM free air?
When a compressor pumps one “CFM” (cubic foot per minute), that means the intake port inhales one cubic foot of “free air” (air at atmospheric pressure, which is 0 psig) per minute. (Note: A CFM does not mean in any sense the compressed volume.)
How many CFM is a kW?
The atmosphere cubic feet / minute unit number 20.91 atm cfm converts to 1 kW, one kilowatt.
What is CFM kW?
CFM refers to Cubic Feet per Minute, which measures the volume of air that is coming out of an air compressor each minute. kW, on the other hand, represents kilowatts or the amount of energy required to power an air compressor. Comparing CFM to kW is like comparing apples and oranges.
How do you calculate CFM from HP?
CFM to HP Definition CFM can be converted into HP by multiplying the airflow by 1.6 and then multiplying that result by 0.9.
How do you calculate the efficiency of a compressor?
A quick estimate of compressor efficiency can be done by taking the ratio of the total loaded hours divided by the total run-time hours. If you find the ratio is very low, say 50%, too many of the compressor hours are spent running unloaded, which is costly and wasteful, and further investigation is warranted.
How many CFM is 100 square feet?
Example: For residential bathrooms up to 100 sq. ft. in area, HVI recommends an exhaust rate of 1 cfm per square foot. A bathroom is 6′ to 10′ or 60 square feet.
How many CFM is a 5 ton unit?
A 5-ton system should have have 2,000 cfm, a 6-ton system should have 2,400 cfm, and so on and son. Measuring how much airflow measurements deviate from that math is a quick way to diagnose airflow issues in a residential duct system.
How do you calculate ventilation rate?
Ventilation rate is expressed as the volume of gas entering or leaving the lungs in a given amount of time. It can be calculated by multiplying the volume of gas, either inhaled or exhaled, during a breath (the tidal volume) by the breathing rate [e.g., 0.4 liter (or 0.4L) × 15 breaths/min = 6L/min].
How many CFM are in a ton?
1 ton of cooling is equal to 400 cubic feet of air per minute. 2 ton of cooling is 800 cfm and so on. So a 4 ton unit will have 1600 cubic feet of air passing through the system every minute.
