Formulas and Conversion

1. Front stage pumping speed of Roots pump: S=(0.1-0.2) S

2. Selection of pumping speed for rough pump: 2.3Kq-v.lg (Pa/P pre)/t

S - Effective pumping speed of mechanical pump (liters/second)

S-Roots pump effective pumping speed (liters/second)

Q1- Vacuum system leakage rate (in liters per second)

P pre - the required pre vacuum degree (tray)

V-Vacuum system volume (liters)

The time required to reach P pre time

Pa - atmospheric pressure value (Torr)

Kp correction coefficient is related to the pressure P at the final value of the equipment