El ambiente

AIR PRESSURE PROBLEM.

Problems.

My compressor is having 45 liters capacity tank & working pressure is 5.2 kg. 4cfm=113L/min is capacity.
How much time will be required tofill it up?

Answer 1.

The math is inverted.
The flow is rated in raw, atmospheric air. The 45 L tank is at pressure, 5 kgf/cm² (I assume that's what he meant) is 4.8 atm,so the 45 L is the equivalent of 216 L at 1 atm.
(I have no idea what the temperature of the compressed air will be, depending on cooler performance, so I'll just ignore it). Then216 L / 113L/min =1.9 minutes.

Ideally both temperature and pressure should be known and used to calculate how many SCF (standard cubic feet) or (liters) are required to fillthe 45 L tank. Some heating of the compressed air is unavoidable, so the tank contents will be somewhat less than 216 standard liters.

Answer 2.

This is why when you convert80cf to liters you get some bizarre number that doesn't seem accurate based on what we know of American Cylinder markings. (80cf = 2265 liters)

The most common question whenit comes to tank size in the USA:

80cf at 3000psi can be represented as:
80cf/ 201.34 ATM = 0.397cf (or cf/ATM)
0.397cf x 28.32L/cf= 11.25 liters

12L tank at 3000psican be represented as:
12L / 28.32 = 0.4237
0.4237 X 201.34 = 85.31cf

12L is approximately an 85 at 3000psi. But working pressure is 200bar or 2900psi, the actual USequivalent is actually "smaller." above the 201.34 represents atmospheres, which is the metric unit bar.

200bar X .4237 = 84.74 Cu FT

A standard European 12L scuba tank is USequivalent 84.74 Cu FT

Table borrowed from Scuba Board.

12 liter = 0.424cf
2250psi tank... 64cf
3000psi tank... 86cf
3300psi tank... 94cf
3500psi tank... 100cf