Electronically controlled flow meter and flow control system

Structure comprising:

• a chamber containing a first and a second opening through which fluid can pass;
• a flexible diaphragm located in said chamber so as to divide said chamber into two subchambers, a first subchamber which is accessed through said first opening and a second subchamber which is accessed through said second opening;
• a magnet attached to said flexible diaphragm, said magnet being formed as an integral part of, and being completely enclosed by, the material of said flexible diaphragm;
• means for directing fluid whose flow is being measured through said first opening into said first subchamber while withdrawing the fluid whose flow is being measured through said second opening from said second subchamber and, in response to a control signal, reversing the subchambers into which the fluid is inserted and from which the fluid is withdrawn, the movement of fluid into one subchamber and out of the other subchamber causing said flexible diaphragm to move into the subchamber from which the fluid is being withdrawn;
• means for producing an output signal representative of the position of said magnet;
• means for converting said output signal to a sequence of digital signals;
• means for processing said sequence of digital signals to produce a second signal representative of the flow rate of said fluid into and out of said chamber;
• means for comparing said flow rate to a reference flow rate to produce a control signal representative of the difference between said measured flow rate and said reference flow rate;
• and
• means, responsive to said control signal, for changing the flow rate of said fluid.

Structure which comprises

• a chamber containing two openings therein;
• a flexible diaphragm containing as a part thereof a magnet, said diaphragm separating said chamber into a first and a second portion and sealing said first portion from said second portion so as to prevent leakage of fluid from said first portion to said second portion or vice versa;
• means for continuously producing an output signal representative of the position of said diaphragm;
• means for selectively controlling the flow into said first portion and out of said second portion and for reversing the flow as desired so that the fluid flows into the second portion and from the first portion;
• means for processing the output signal from said means for producing including
• switching path means for selectively accessing the output signal from said means for producing
• conversion means for converting said output signal from said means for producing to a first digital signal;
• buffer means for storing said first digital signal from said conversion means;
• means for inputting to said system a second digital signal representing a desired fluid flow rate;
• means for storing said second digital signal representing said desired fluid flow rate;
• processing means for operating on said first and second digital signals to produce an estimate of the flow rate of fluid into and out of said chamber;
• means for storing a signal representative of the flow rate calculated by said processing means;
• and
• driver circuit means periodically actuated by said output signal from said processing means to move a control valve either open or closed in response to the output signal stored in said means for storing.

The method of measuring a fluid flow rate using a chamber containing a first opening and a second opening through which fluid can pass with a flexible diaphragm located in said chamber so as to divide said chamber into two subchambers, a first subchamber which is accessed through said first opening and a second subchamber which is accessed through said second opening, and a magnet attached to said flexible diaphragm, comprising:

• directing the fluid whose flow is being measured through said first opening into said first subchamber while withdrawing the fluid whose flow is being measured through said second opening from said second subchamber and, in response to a control signal, reversing the subchambers in which the fluid is inserted and from which the fluid is withdrawn, the movement of fluid into one subchamber and out of the other subchamber causing said flexible diaphragm to move into the subchamber from which the fluid is being withdrawn;
• producing a continuous output signal representative of the position of said magnet;
• converting said output signal to a sequence of digital signals;
• processing said sequence of digital signals to produce a second signal representative of the flow rate of said fluid into and out of said chamber;
• comparing said flow rate to a reference flow rate to produce a control signal representative of the difference between said measured flow rate and said reference flow rate;
• and
• changing the flow rate of said fluid in response to said control signal.