Gas filling system

Abstract

A system and method for supplying a gas from a supply of compressed gas to a receiving vessel by measuring the pressure of gas being directed into the receiving vessel in successive selected time intervals to determine the actual ramp rate of gas being directed into the receiving vessel and providing means for comparing the actual ramp rate with a desired ramp rate and controlling the gas flow rate in response to that comparison. In a preferred embodiment the pressure of the gas at an upstream end of the system is monitored and directed into a controller and this latter pressure is employed in determining the mass flow of gas into the receiving vessel.

1 . A gas filling system for supplying a gas from a supply of compressed gas to a receiving vessel, said filling system including: 
 a. a source of compressed gas;    b. a receiving conduit communicating the source with a plurality of gas transmission lines in parallel with each other;    c. a delivery conduit communicating with a receiving vessel and with said plurality of gas transmission lines;    d. a control valve in each of a plurality of said gas transmission lines upstream of said delivery conduit for communicating said each of said plurality of gas transmission lines with said delivery conduit when in an opened condition; at least some of said gas transmission lines having differing orifice coefficients for transmitting gas at different flow rates therethrough;    e. a flow controller for opening and closing selected control valves to control the flow rate of gas to said receiving vessel and having a desired ramp rate communicating therewith;    f. a pressure monitor downstream of the control valves for measuring the pressure of gas being directed into the receiving vessel in selected time intervals and continuously transmitting said pressure of gas to said flow controller, said flow controller comparing the desired ramp rate communicating therewith with said pressure of gas and controlling the flow rate of gas through the transmission lines to said receiving vessel based upon the comparison of the desired ramp rate with said pressure of gas.    
     
     
         2 . The gas filling system of  claim 1 , wherein said flow controller is a programmable logic controller having the desire ramp rate programmed therein.  
     
     
         3 . The gas filling system of  claim 1 , wherein the desire ramp rate is transmitted to the flow controller from another source.  
     
     
         4 . The gas filling system of  claim 1 , wherein said pressure monitor measures pressure of gas in said delivery conduit in selected time intervals.  
     
     
         5 . The gas filling system of  claim 1 , wherein each gas transmission line has an orifice coefficient different from the orifice coefficient in every other gas transmission line.  
     
     
         6 . The gas filling system of  claim 5 , wherein each orifice coefficient differs from the next smallest orifice coefficient by a factor of substantially 2.  
     
     
         7 . The gas filling system of  claim 1 , wherein said pressure monitor measures an increase in pressure in successive selected time intervals, which constitutes an actual ramp rate of gas being directed into said receiving vessel, said flow controller comparing the actual ramp rate with the desired ramp rate and controlling the flow rate of gas through the transmission lines to said receiving vessel based upon the difference between the actual ramp rate and the desired ramp rate.  
     
     
         8 . The gas filling system of  claim 7 , wherein said flow controller increases the flow rate of gas when the actual ramp rate is lower than the desired ramp rate and decreases the flow rate of gas when the actual ramp rate is higher than the desired ramp rate.  
     
     
         9 . The gas filling system of  claim 1 , including a second pressure monitor upstream of said transmission lines for measuring gas pressure upstream of said transmission lines and transmitting data representative of said gas pressure upstream of said transmission lines to said flow controller; said flow controller including data representative of the size of orifices in transmission lines communicating with said delivery conduit through opened control valves, said flow controller including means for processing data representing said gas pressure upstream of said transmission lines and data representative of the size of orifices in transmission lines communicating with said delivery conduit through opened control valves for determining the mass flow of gas into said receiving vessel.  
     
     
         10 . The gas filling system of  claim 1 , including a second pressure monitor upstream of said transmission lines for measuring gas pressure upstream of said transmission lines and transmitting data representative of said gas pressure upstream of said transmission lines to said flow controller; said flow controller determining the ratio of the pressure measured downstream of said transmission lines to the pressure measured upstream of said transmission lines and determining the mass flow of gas into said receiving vessel based upon said ratio.  
     
     
         11 . A method of filling a receiving vessel from a source of compressed gas employing a system including a receiving conduit communicating with said source of compressed gas and with a plurality of transmission lines in parallel with each other; a deliver conduit downstream of said plurality of transmission lines communicating with said receiving vessel, a control valve in each of a plurality of said gas transmission lines upstream of said delivery conduit for communicating said each of said plurality of gas transmission lines with said delivery conduit when in an opened condition; at least some of said gas transmission lines having differing orifice coefficients for transmitting gas at different flow rates therethrough and a flow controller for opening and closing selected control valves to control the flow rate of gas to said receiving vessel, said flow controller having a desired ramp rate communicating therewith, said method including the steps of measuring the pressure of gas being directed into the receiving vessel in successive selected time intervals to determine actual ramp rate of gas being directed into the receiving vessel; comparing the actual ramp rate with the desired ramp rate and controlling gas flow through said plurality of transmission lines in response to said comparison.  
     
     
         12 . The method of  claim 11 , including the step of monitoring the pressure of gas upstream of said control valves, determining the size of orifices in transmission lines communicating with said receiving conduit through opened control valves and calculating the mass flow of gas into said receiving vessel based upon said pressure of gas upstream of said control valves and the size of orifices in transmission lines communicating with said receiving conduit through opened control valves.  
     
     
         13 . The method of  claim 11 , including the step of monitoring the pressure of gas upstream of said control valves, determining the ratio of the pressure of gas being directed into the receiving vessel to the pressure of gas upstream of said control valves and based upon said ratio calculating the mass flow of gas into said receiving vessel.  
     
     
         14 . A method of filling a receiving vessel from a source of compressed gas including the steps of measuring pressure of gas being directed into the receiving vessel in successive selected time intervals to determine actual ramp rate of gas being directed into the receiving vessel; comparing the actual ramp rate with a desired ramp rate and controlling gas flow rate into said receiving vessel in response to said comparison.  
     
     
         15 . The method of  claim 14 , wherein the step of controlling gas flow rate is carried out by increasing the gas flow rate when the actual ramp rate is lower than the desired ramp rate and be decreasing the gas flow rate when the actual ramp rate is higher than the desired ramp rate.  
     
     
         16 . The method of  claim 14 , including the steps of measuring gas pressure between said source and a plurality of transmission lines in parallel with each other and including control valves therein, said control valves being operable between opened and closed conditions, transmission lines with opened valves therein communicating said source with a delivery conduit communicating with said receiving vessel downstream of said transmission lines, determining the size of orifices in transmission lines communicating with said delivery conduit through opened control valves and calculating the mass flow of gas into said receiving vessel based upon said pressure of gas upstream of said control valves and the size of orifices in transmission lines communicating with said delivery conduit through opened control valves.  
     
     
         17 . The method of  claim 14 , including the steps of measuring gas pressure between said source and a plurality of transmission lines in parallel with each other and including control valves therein, said control valves being operable between opened and closed conditions, transmission lines with opened valves therein communicating said source with a delivery conduit communicating with said receiving vessel downstream of said transmission lines, determining the ratio of the pressure of gas being directed into the receiving vessel to the pressure of gas between said source and said plurality of transmission lines and based upon said ratio calculating the mass flow of gas into said receiving vessel.