Fuente: WIPO "milk" A metering apparatus comprises a pipe (10) through which milk is fed from a farm vat (11) to a tanker mounted collection vessel (12). A turbine flow meter (13) and valves (V2, V3) downstream and upstream of the meter are arranged in the pipe (10). Upstream of valve (V3) there is arranged a deaerating vessel (14) with a venting pipe (16) leading, via a valve (V1) from the top of vessel (14) to the top of vessel (12). Probes (P1 to P5) detecting the presence of air in the milk and, monitored by a control unit (100) (not shown) control the operation of the valves (V1 to V3). The control unit (100) has a printer which issues a ticket showing the metered volume and a flag indicating if the reading is valid or invalid.