Abstract: Apparatus for performing chemical analysis wherein a cuvette holds a sample under examination and a support carries a dispenser head carrying two one-shot dispensers each in the form of a pressurized container holding a liquid reagent, of which a metered does is delivered into the cuvette through a discharge tube fixed to the dispenser head when the body of the container is displaced relative to said discharge tube.

Abstract: A pressurized metering dispenser comprises a main reservoir, a liquid metering chamber and a gas chamber. A valve arrangement enters the reservoir and the gas chamber from an outlet nozzle at the end of a central passage, the inboard end of which is above the level of liquid in the reservoir when the dispenser is held nozzle-down. A gas holding chamber communicates with the gas chamber and the liquid metering chamber with the reservoir in a normal state, and actuation is achieved by upward displacement of the nozzle to start off the liquid and gas holding chambers and from their supplies and finally cause the chamber to communicate with the chamber to cause the liquid to be expelled through the nozzle under the gas pressure in the chamber. A holder for such a dispenser includes an actuating lever and counter to indicate the number of actuations.