Electronic display flow meter

A transducer for a fluid flow meter having a stem moving vertically in response to changes in flow, said stem having a magnet rigidly attached thereto, said transducer comprising:

• a first bar of generally uniform cross section having an axis parallel to the direction of movement of said magnet, said first bar being an electrically conductive polished cylindrical rod of non-magnetic metal;
• a second bar of generally uniform cross section having a first end, a second end and an axis parallel to the axis of said first bar, said second bar being non-magnetic and comprising a tight helical winding of fine electrically resistive wire disposed on a non-magnetic core;
• an electrically conductive, magnetically attractable metallic spherical contact means movably engaging said first bar and said second bar whereby said first bar and said second bar are in electrical contact with one another through said contact means;
• power supply means providing a first reference voltage to said second bar first end and a second reference voltage different from said first reference voltage to said second bar second end;
• and
• signal carrying means electrically connected to said first bar and obtaining a signal therefrom indicative of contact means position.

A fluid flow meter comprising:

• a body portion having an inlet port, an outlet port and a chamber connecting the inlet port to the outlet port;
• a movable stem within said chamber, said stem adapted to change position in response to changes in flow through said chamber such that the position of said stem is indicative of flow rate;
• a magnet fixed to said stem;
• and
• a transducer outside of said chamber comprising a resistor bar having first and second ends, a contact bar and indicator means, said resistor bar being connected to a source of reference voltage at said first end and a source of reference ground at said second end, said contact bar being connected to a position signal line, and said indicator means adapted to be attracted to said magnet and making electrical contact between said resistor bar and said contact bar at a point adjacent said magnet thereby creating a position signal on said position signal line.

A fluid flow meter comprising:

• a body portion having an inlet port, an outlet port and a chamber connecting the inlet port to the outlet port;
• a movable stem within said chamber, said stem adapted to change position in response to changes in flow through said chamber such that the position of said stem is indicative of flow rate;
• a magnet fixed to said stem;
• and,
• a transducer comprising a resistor bar having a circular cross section, a first diameter and first and second ends, a contact bar having a circular diameter and a second diameter different from said first diameter, and steel ball indicator means having a ball diameter and adapted to be attracted by said magnet, said resistor bar being connected to a source of reference voltage at said first end and a source of reference ground at said second end, said contact bar being connected to a position signal line, and said indicator means adapted to be attracted to said magnet and making electrical contact between said magnet thereby creating a position signal on said position signal line;
• an analog to digital converter adapted to receive said position signal and create a digital position signal dependent on said position signal;
• a memory means containing correction data, said memory means adapted to output one correction datum corresponding to said digital position signal;
• a digital to analog converter adapted to receive said correction datum and create an analog correction signal based on said correction datum;
• and,
• an analog adder means adapted to add said analog correction signal and said position signal and create a corrected position signal based thereon.

A fluid flow meter comprising:

• a body portion having an inlet port and an outlet port;
• a core tube within said body portion having an inlet in flow communication with said inlet port and having an outlet in flow communication with said outlet port;
• a movable stem within said core tube comprising a piston, a connecting rod and a magnet holder, said piston adapted to allow flow through a variable portion of said core tube outlet dependent piston position, whereby piston position is dependent on fluid flow through said meter;
• a magnet contained within said magnet holder;
• an envelope fixed to said body portion enclosing said magnet holder;
• a raceway fixed to said envelope, said raceway comprising first and second parallel bars;
• said raceway first parallel bar having a first circular cross section, a first diameter and comprises a resistor having a first end and a second end, said first end connected to a first source of reference voltage, said second end connected to a second source of reference voltage;
• said second parallel bar having a second cross section and a second diameter different from said first diameter and is connected to a signal output line;
• a ball contact means movable in said raceway, said contact means adapted to be attracted to said magnet and being electrically conductive whereby said raceway and contact means function as a potentiometer having an output on said signal output line indicative of contact means position;
• an electrical means sensing the position of said contact means in said raceway and generating a signal indicative of said position;
• and
• a signal carrying means accepting said signal and conveying it to a display means, said display means accepting said signal from said signal carrying means and creating a visually perceptible representation based upon said signal.

A fluid flowmeter comprising:

• a body portion having an inlet port and an outlet port;
• a core tube within said body portion having an inlet in flow communication with said inlet port and having an outlet in flow communication with said outlet port;
• a movable stem within said core tube comprising a piston, a connecting rod and a magnet holder, said piston adapted to allow flow through a variable portion of said core tube outlet dependent piston position, whereby piston position is dependent on fluid flow through said meter;
• a magnet contained within said magnet holder;
• an envelope fixed to said body portion enclosing said magnet holder;
• a raceway fixed to said envelope, said raceway comprising first and second parallel bars;
• said first parallel bar comprises a resistor having a first end and a second end, said first end connected to a first source of reference voltage, said second end connected to a second source of reference voltage;
• said second parallel bar being connected to a signal output line;
• contact means movable in said raceway, said contact means adapted to be attracted to said magnet and being electrically conductive whereby said raceway and contact means functions as a potentiometer having an output on said signal output line indicative of contact means position;
• said signal output line conveying a contact position signal to a signal processing unit comprising:
• an analog to digital converter adapted to receive said contact position signal and create a digital position signal dependent on said contact position signal;
• a memory means containing correction data, said memory means adapted to output one correction datum corresponding to said digital position signal;
• a digital to analog converter adapted to receive said correction datum and create an analog correction signal based on said correction datum;
• and,
• an analog adder means adapted to add said analog correction signal and said contact position signal and create a corrected position signal based thereon.

A transducer for a fluid flow meter having a stem moving vertically in response to changes in flow, said stem having a magnet rigidly attached thereto, said transducer comprising:

• a first bar of generally uniform circular cross section having an axis parallel to the direction of movement of said magnet and a first diameter generally constant over the length of the first bar, said first bar being electrically conductive and non-magnetic;
• a second bar of generally uniform circular cross section having a first end, a second end and an axis parallel to the axis of said first bar and a second diameter generally constant over the length of said second bar, said second bar being non-magnetic and electrically resistive along its length;
• said first and second bar diameters being related to one another by a factor of approximately two;
• an electrically conductive, magnetically attractable contact means movably engaging said first bar and said second bar whereby said first bar and said second bar are in electrical contact with one another through said contact means;
• power supply means providing a first reference voltage to said second bar first end and a second reference voltage different from said first reference voltage to said second bar second end;
• and,
• signal carrying means electrically connected to said first bar and obtaining a signal therefrom indicative of contact means position.

A transducer for a fluid flow meter having a stem moving vertically in response to changes in flow, said stem having a magnet rigidly attached thereto, said transducer comprising:

• a first bar of generally uniform circular cross section having an axis parallel to the direction of movement of said magnet and a first diameter generally constant over the length of the first bar, said first bar being electrically conductive and non-magnetic;
• a second bar for generally uniform circular cross section having a first end, a second end and an axis parallel to the axis of said first bar and a second diameter generally constant over the length of said second bar, said second bar being non-magnetic and electrically resistive along its length;
• said first and second bar diameters being related to one another by a factor of approximately five-thirds;
• an electrically conductive, magnetically attractable contact means movably engaging said first bar and said second bar whereby said first bar and said second bar are in electrical contact with one another through said contact means;
• power supply means providing a first reference voltage to said second bar first end and a second reference voltage different from said first reference voltage to said second bar second end;
• and,
• signal carrying means electrically connected to said first bar and obtaining a signal therefrom indicative of contact means position.

A fluid flow meter comprising:

• a body portion having an inlet port, an outlet port and a chamber connecting the inlet port to the outlet port;
• a movable stem within said chamber, said stem adapted to change position in response to changes in flow through said chamber such that the position of said stem is indicative of flow rate;
• a magnet fixed to said stem;
• and,
• a transducer comprising a resistor bar having a circular cross section, a first diameter and first and second ends, a contact bar having a circular cross section and a second diameter different from said first diameter, and steel ball indicator means having a ball diameter and adapted to be attracted by said magnet, said resistor bar being connected to a source of reference voltage at said first end and a source of reference ground at said second end, said contact bar being connected to a position signal line, and said indicator means adapted to be attracted to said magnet and making electrical contact between said resistor bar and said contact bar at a point adjacent said magnet thereby creating a position signal on said position signal line.