Vacuum systems are often designed so that some sort of pump set or mechanical vacuum pump is able to evacuate both the chamber and piping of the system within a period of time. It can be helpful to be able to accurately calculate the amount of time it will take for the vacuum to be evacuated, especially in laboratories and other research environments.
Having a clear picture of evacuation time can be helpful in an industrial environment as well. There are a number of factors that can influence the evacuation time of a vacuum. For example, if the pump attached to the vacuum is on the larger side, the vacuum may be faster to evacuate. Of course, larger pumps are also more expensive than their smaller counterparts.
You can get fairly accurate results from both methods. Keep in mind, you that these calculations were specifically designed for basic systems, and the calculations assume that the vacuum chamber isn't full.
Calculating The Evacuation Time: Basic Equation
To calculate the evacuation time of your vessel, you'll want to use this formula V / S = T.
V stands for volume, S stands for pumping speed, and T stands for time. You'll want to make sure that the measurement units used are consistent. For example, if you're measuring time in minutes, you would want to measure volume in liters and speed by liters per minute.
This formula is fairly basic, but it's still effective. The formula takes into consideration the original pumping capacity of the vacuum pump, and the size of your chamber. To get the most accurate number, it is important to consider all of the connecting fittings and tubing that the vacuum pump will be pumping on. For example, if you have a 1 cubic foot chamber, and there are 20 feet of tubing in between the pump and the chamber, you would need to include the volume of the 20 foot of tubing in addition to the volume of the chamber.
If you need more information for this calculation, you should be able to find it in the manual that came with your vacuum. You'll want to make sure you have an accurate measure of the pumping speed of your vacuum. That way, you'll be able to ensure that the results of your calculation are correct.
Even when you have these formulas to work with, accurately calculating evacuation speed is a challenge. Thankfully, you may be able to get a better picture of the evacuation speed for your vacuum by doing a little bit of research. You can read about the type of vacuum you have and see what other people have to say about its evacuation speed. You may want to do the same thing if you are using a pump set to increase the evacuation speed.
