| 摘要 |
<p>A metering valve includes a main valve and a pilot valve for operating the main valve. A low operating force pawl and ratchet system rotates a cam to open the pilot valve to initiate a cycle of operation. When the main valve is opened, a turbine wheel in the flow path rotates to measure flow. Turbine rotation is transmitted to the cam through a reducing gear assembly and a lost motion connection in order to reclose the pilot and main valves after a predetermined volume of flow is measured.</p> |
