Basic knowledge of vacuum technology : Calculation of Pumping time

　If you know the volume of the vacuum chamber, the required pressure and the time it takes to reach that pressure, you can use the following formula and exhaust rate curve to select a vacuum pump.

【example 1】

　Which vacuum pump should I choose when I want to decompress a 50 liter chamber from atmospheric pressure to 10,000 Pa in 5 minutes? First, substitute the numerical value into the formula to find the exhaust speed at 10,000 Pa.

　At 10,000 Pa, an exhaust speed of 23 L/min or more is required. Look at the Pumping speed curve and select a vacuum pump with an exhaust speed of 23 L / min or more at 10,000 Pa.

　The place marked with "×" is the place where the exhaust speed is 23 L / min when 10,000 Pa. Select DA-41D or DAT-50D, which have a higher exhaust speed.

●Caution

　This calculation does not take into account details such as pipe length, thickness, pipe resistance, and leaks. Actually, select it in consideration of the safety factor.

【example 2】

　How long does it take to decompress an 80 liter vacuum chamber from atmospheric pressure to 13 kPa using DA-121D? Divide into arbitrary pressures, calculate the exhaust time for each section, and add them up.

●Caution

　This calculation does not take into account details such as pipe length, thickness, pipe resistance, and leaks. Actually, select it in consideration of the safety factor.

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