581,248. Gas meters. COMPANIA PARA LA FABRICACION DE CONTADORES Y MATERIAL INDUSTRIAL, SOC. ANON., and VITEAU, P. July 10, 1944, No. 13133. [Class 54] Gas measuring apparatus comprises the combination of a large capacity, rotary piston meter with a small meter, a three-way valve being provided for automatically connecting the meters in series when the output is low and for disconnecting the small meter when it is high ; the counting mechanism is cut out on low output. The gas enters through the inlet 1 and passes to the three-way valve 2 actuated by a membrane 3, thence to the small meter 4 and on to the rotary meter 5, or directly into the latter depending on the setting of the valve. The setting device includes a magneto 12 driven by the meter 5 and actuating a relay 13 with contacts 14, 15 connected to a contactor 16 actuating a valve 17. On increase of output the contact 15 is closed and the winding 21 short circuited to open the contactor 16 and connect the counting mechanism 18, The valve 17 assumes its bottom position and the under side of the membrane 3 is exposed to atmosphere which lowers the valve 2 to the position shown to cut out the small meter 4. In a modification, the three-way valve is operated pneumatically, the gas passing through a venturi the pressure difference acting on a membrane controlling the three-way valve.