DANGER: Whenever there is reduced pressure on glassware there is the possibility that the glassware might implode. All glassware should be free of chips or cracks and should be clamped into place so that the flask cannot accidentally be dropped or bumped.
Mechanical Vacuum Pump
Check to make sure that the vacuum pump is turned on. With the hose clamp on the trap unclamped, open the valve connected to the vacuum pump by rotating the handle until it is parallel to the nozzle. Close the clamp on the trap. Check that the filtration apparatus has a vacuum by passing your hand over the funnel.
A full vacuum on a filter can be disasterous. A gentler vacuum can be affected by intentionally creating a leak in the apparatus. A slight leak can be created by not allowing the hose clamp to completely seal the pressure release tube.
Water Aspirator
A water aspirator can also be used to create a vacuum. With the pinch clamp on the trap open, turn the water on to a full flow. Close the pinch clamp. Check that the apparatus has a vacuum by passing your hand over the funnel.
ALWAYS release the vacuum before attempting to remove the funnel.
