Fluid metering apparatus and method

摘要

An apparatus and method for metering fluid flow is disclosed. A fluid dispensing unit is coupled between a supply pipe and a demand pipe, and dispenses fluid received from the supply pipe to the demand pipe. The demand pipe is coupled to one or more fluid-expending appliances. The pressure of the fluid in the demand pipe is monitored by a fluid information unit. The fluid information unit and fluid dispensing unit cooperate to maintain the fluid flowing through the demand pipe at a substantially constant demand fluid pressure by monitoring fluid flowing through the demand pipe and actively dispensing fluid received from the supply pipe into the demand pipe to maintain the demand fluid pressure at a pre-established demand pressure level. The fluid information unit and fluid dispensing unit also cooperate to meter or measure the volume of fluid dispensed through the fluid dispensing unit. The fluid dispensing unit includes a controllable valve responsive to valve control signals produced by the fluid information unit. The volume of fluid dispensed through the valve is computed using the difference between the supply and demand fluid pressures and a duration of time during which the fluid is flowing through the valve. Alternatively, the volume of dispensed fluid is computed using the supply and demand fluid pressure difference and a characteristic duty cycle factor or characteristic flow factor of the valve.