If the schematic diagram is connected to the trachea and copper head (check the sealing ring of the copper head before insertion and apply the proper amount of grease, then beat the manual vacuum pump to the value of 15 in. Hg, and hold it for 10-20 minutes if the observed value is still between 14-15 in. Hg, the airtightness is good, if it is lower than this value, the airtightness is bad.

After using, press the pressure relief switch of the manual vacuum pump, pull off the copper head and screw the plug.