Abstract: A dispensing device is disclosed which includes a tubular body having front and rear ends, the body having a central bore which narrows at the front thereof to form a tip. A piston is slidable in the bore, the bore space in the body forward of the piston defining a chamber. A supply bottle is removably mounted at the rear of the piston. The piston has a communicating passage between the bottle and the chamber. A first one-way valve means restricts flow in the communicating passage to occur only from the bottle toward the chamber. Also, a second one-way valve means restricts flow as between the chamber and the tip to occur only from the chamber toward the tip. The first one-way valve means includes a hollow valve body having one end which opens into the chamber and at least one port which communicates between the communicating passage and the inner region of the valve body.

Abstract: A pipetting device which is readily adaptable to serve as a pipetting/diluting device. In accordance with the invention there is provided a tubular body having front and rear ends, the body having a central bore which narrows at the front end thereof to form a tip. A hollow enclosure is provided and defines a back chamber. A plunger is slideable in the bore and extends from the rear thereof for manual activation. The plunger has a front portion which conforms circumferentially to the inner surface of the body, the bore space in the body forward of the plunger defining a front chamber. The plunger has a communicating passage between the back and front chambers. A first one way valve means restricts flow in the communicating passage to occur only from the back chamber toward the front chamber. Finally, a second one way valve means restricts flow as between the front chamber and the tip to occur only from the front chamber toward the tip.