Patent ID: 7413711

Claim:
An apparatus for delivering a predetermined amount of a fluid for biological or chemical processing and/or analysis, consisting of: a tube; a piston plunger positioned to slide inside of said tube for dispensing said predetermined amount of a fluid for biological or chemical processing and/or analysis, said piston plunger responsive to a pneumatic force; a mechanical device that biases said piston plunger in opposition to said pneumatic force; a connector operatively connected to said tube for transferring said predetermined amount of a fluid for biological or chemical processing and/or analysis; a chamber directly connected to said tube and open to said piston plunger for directing said pneumatic force directly to said piston plunger, an actuator operatively connected to said chamber, said tube and piston plunger for providing said pneumatic force to said piston plunger; and valving in said actuator operatively connected to said chamber and said tube and operatively connected to said piston plunger, said valving transmitting said pneumatic force to said chamber, said tube and piston plunger.