APARATO DE MANOMETRO MEJORADO PARA DOSIFICAR CANTIDADES IGUALES SUCESIVAS DE UNA SUSPENSION LIQUIDA A TRAVES DE UN INSTRUMENTO AL QUE ESTA CONECTADO AL MANOMETRO

摘要

A manometer is provided for metering samples of fluid flowing in devices wherein particle concentration in the fluid is being counted or measured. Such devices include particle counters for determining blood cell concentration in body fluid. The device includes low permeable stretchable diaphragms in the device connections for containing the mercury therein, and a slide valve in the vent connection to restrict the movement of the mercury during storage or shipment. The arrangement herein includes, also, a one-way valve downstream of the "stop" point to stop flow substantially immediately upon the cessation of the measurement interval to reduce unwanted airflow to the counting aperture. A start and stop arrangement in the mercury flow path for causing the leading edge of the mercury meniscus at the axis thereof to engage the electrode contacts includes simple wire tips extending into the mercury flow path to the axis thereof for engaging the axis of the mercury meniscus. A preset fixed sample volume metering chamber is provided which eliminates the need for calibration.