10-14-2020, 08:25 AM
High vacuum system pumping
One of the fundamental considerations in planning a high vacuum system is the time required to pump the vessel to a given pressure. The scale of this moment usually ranges from a few minutes to a few hours. However, in some cases, the pumping time may be seconds or days. It is very difficult to estimate the connection between time and pressure by theoretical or experimental methods, because the outgassing rate (outgassing or virtual leakage) on the inner and outer surface of the container can not be recognized, but the time and pressure of air extraction are related to the rate of outgassing.
The outgassing of the given data depends on the temperature, the surface finish, the exposure to various atmospheres prior to this, and the cleaning method. When the outgassing is significant, even an approximate estimation of the exhaust time may be very difficult. The planner can estimate the pressure time curve from atmospheric pressure to about 10-2 Torr by using a connection equation suitable for higher pressure. According to the steady state (long time) outgassing data and the characteristics of the pumping equipment, the ultimate (limit) pressure can sometimes be estimated. The most interesting region is from 10-2 torr to the limit pressure.
Water Ring Vacuum Pump
Dry Scroll Vacuum Pump
industrial vacuum pumps,vacuum furnaces
One of the fundamental considerations in planning a high vacuum system is the time required to pump the vessel to a given pressure. The scale of this moment usually ranges from a few minutes to a few hours. However, in some cases, the pumping time may be seconds or days. It is very difficult to estimate the connection between time and pressure by theoretical or experimental methods, because the outgassing rate (outgassing or virtual leakage) on the inner and outer surface of the container can not be recognized, but the time and pressure of air extraction are related to the rate of outgassing.
The outgassing of the given data depends on the temperature, the surface finish, the exposure to various atmospheres prior to this, and the cleaning method. When the outgassing is significant, even an approximate estimation of the exhaust time may be very difficult. The planner can estimate the pressure time curve from atmospheric pressure to about 10-2 Torr by using a connection equation suitable for higher pressure. According to the steady state (long time) outgassing data and the characteristics of the pumping equipment, the ultimate (limit) pressure can sometimes be estimated. The most interesting region is from 10-2 torr to the limit pressure.
Water Ring Vacuum Pump
Dry Scroll Vacuum Pump
industrial vacuum pumps,vacuum furnaces