Device for more economical standby operation of continuous-flow analyzers

To decrease the reagent-consumption rate of continuous-flow analyzers, I constructed a device that allows standby operation. The device, when actuated by switching off the sampler, decreases the effective pumping rate to less than 1/15 normal. The bubble pattern remains virtually undisturbed, and the system can be immediately restarted for emergency use. During five months of use in our laboratory with a Technicon platelet counter, the device was decreased reagent consumption by 60%, while allowing 24-hour-a-day operation. There have been no analytical errors traceable to the device, and no mechanical problems have arisen. I describe the use of the device in a continuous-flow system for determination of creatinine.