Fluid metering system

A fluid metering apparatus for the delivery of a fluid at a desired flow rate, said apparatus comprising:

• (a) a gas inlet;
• (b) a first regulator in fluid communication with said gas inlet and configured to receive a gas from said gas inlet and emit said gas from a first regulator gas outlet at a first gas pressure;
• (c) a second regulator in fluid communication with said first regulator gas outlet and configured to receive said gas from said first regulator gas outlet and emit said gas at a second gas pressure, wherein said first gas pressure is higher than said second gas pressure;
• (d) a first valve in fluid communication with said first regulator;
• (e) a second valve in fluid communication with said second regulator;
• (f) a switch mechanism connected to said first valve and said second valve and having a first actuator and a second actuator, wherein said switch mechanism causes said first valve to be open and said second valve to be closed when said first actuator is actuated and causes said second valve to be open and said first valve to be closed when said second actuator is actuated;
• (g) a fluid pressure regulating device having:
• i. a fluid inlet port configured to receive a fluid to be metered, wherein said fluid has a fluid inlet pressure;
• ii. a gas inlet port in fluid communication with said first valve and said second valve;
• and
• iii. a fluid outlet port,
• wherein when said first actuator of said switch mechanism is actuated, said fluid pressure regulating device is configured to deliver said fluid to said fluid outlet port at a first device outlet flow rate which is proportional to a predetermined ratio of said fluid inlet pressure and said first gas pressure and wherein, when said second actuator of said switch mechanism is activated, said fluid pressure regulating device is configured to deliver said fluid to said fluid outlet port at a second device outlet flow rate which is proportional to a predetermined ratio of said fluid inlet pressure and said second gas pressure;
• (h) a fluid outlet;
• and
• (i) an orifice fitting in fluid communication with said fluid outlet port and configured to effect a pressure drop between said fluid outlet port and said fluid outlet.

A fluid metering apparatus for the delivery of a fluid at an Ni delivery flow rate, wherein N is any integer greater than 1 and i is any integer from 1 to N, said apparatus comprising:

• (a) a gas inlet for receiving a gas;
• (b) N regulators, wherein each said Ni regulator is in fluid communication with said gas inlet and is configured to emit said gas at a corresponding Ni gas pressure;
• (c) N valves wherein each Ni valve is in fluid communication with a corresponding Ni regulator;
• (d) a switch mechanism connected to each valve and having N actuators, wherein said switch mechanism opens an Ni valve and closes the remaining valves when a corresponding Ni actuator is actuated;
• (e) a fluid pressure regulating device having:
• (i) a fluid inlet port configured to receive a fluid to be metered, wherein said fluid has a fluid inlet pressure;
• (ii) a gas inlet port in fluid communication with each valve;
• and
• (iii) a fluid outlet port,
• wherein, when an Ni actuator of said switch mechanism is actuated, said fluid pressure regulating device is configured to deliver said fluid to said fluid outlet port at a device outlet flow rate which is proportional to a predetermined ratio of said fluid inlet pressure and an Ni gas pressure, which Ni gas pressure corresponds to an Ni actuator;
• (f) a fluid outlet configured to emit said fluid at an Ni delivery flow rate;
• and
• (g) an orifice fitting in fluid communication with said fluid outlet port and configured to effect a pressure drop between said fluid outlet port and said fluid outlet.