Rubber bulb

Rubber bulbs are pieces of lab equipment used to create suction in pipettes or burettes in order to fill said glassware with a solution of a liquid reagent.

General

Rubber bulbs are round-shaped silicone or natural rubber items, with at least two openings, one for creating vacuum in a pipette and the other to release the air from the bulb. By pressing a push valve, the liquid is drawn in the pipette. More advanced models have a T-adaptor that allows the liquid from the pipette to be released without having to eliminate the vacuum from the bulb.

Types

• Simple: has a prolate spheroid shape, with some models having a plastic tube and a rubber adapter, to seal better on the glass pipette
• Aspirator: often used in automatic burettes
• Three-way bulb filler: has a T-shaped connector with 2 push valves and one push valve on the top of the bulb
• Dropper bulb: used in droppers and glass Pasteur pipettes

Availability

Rubber bulbs or all kinds can be bought from lab suppliers. They can also be found online, eBay and Amazon are good place to start.

DIY rubber bulb

Bulb syringe or nasal aspirators can be used as pipette bulbs, though you may need to cut the stem for the rubber to fit on the pipette.

See also

• Dropper
• Pipette pump

References

Relevant Sciencemadness threads

• Pipette bulb filler
• Pipette Pumps