Ultrasonic linear meter sensor for positive displacement meter

A method for real time measurement of the volume or quantity of liquid passing under pressure through a metering pump prior to delivery to a nozzle, said metering pump including at least one piston that moves on a downstroke within a cylinder when liquid is forced under pressure into the cylinder, and moves on an upstroke for delivering a measured amount of liquid to said nozzle from said cylinder, said method comprising the steps of:

• periodically transmitting an acoustical signal along a path transverse to the longitudinal axis of said piston at an uppermost portion of the interior of said cylinder;
• reflecting said signal from its transverse path downward along a path intersecting a top face of said piston;
• reflecting a portion of said signal as a return signal from the face of said piston along a return path parallel to the longitudinal axis of said cylinder;
• reflecting the return signal near an uppermost portion of said cylinder along a path transverse to the longitudinal axis of said cylinder;
• detecting said return signal along its transverse return path at the location of a source of said acoustical signal;
• measuring the time difference between the times for successive pairs of transmitted acoustic signals to be reflected and detected;
• and
• calculating from the measured time differences the volume displacement of said piston in reciprocating within said cylinder between successive transmitted signals, the volume being equivalent to the liquid delivered to said nozzle during the time interval represented by said time difference.

In a rotary positive displacement piston meter for metering or measuring the volume of fluid dispensed from a dispensing system, said rotary positive displacement piston meter includes first and second pistons mounted within first and second opposing cylinders, respectively, and third and fourth pistons mounted within third and fourth opposing cylinders, respectively, said first and second pistons reciprocating in opposition to one another within their respective cylinders, and said third and fourth pistons reciprocating in opposition to one another within their respective cylinders, each of said first through fourth pistons move in a downstroke when fluid under external pressure is forced into their respective cylinder, and in an upstroke for forcing fluid out of their respective cylinder for dispensing, the total volume displaced by the pistons within respective cylinders during a given dispensing cycle being equivalent to the total volume of fluid dispensed, wherein the improvement comprises:

• first ultrasonic detection means mounted within either said first or second cylinder for periodically providing successive first and second displacement signals indicative of the displacement of at least said first and second pistons within said first and second cylinders, respectively, between the times of occurrence of said first and second displacement signals as said pistons reciprocate therein over a given dispensing cycle;
• said first ultrasonic detection means including a first ultrasonic transducer mounted in an outermost side of the associated said first or second cylinder, for transmitting and receiving acoustic signals along a first signal path transverse to the longitudinal axis of the associated said first or second piston, and reflector means for establishing a signal path between said first ultrasonic transducer means and the associated one of said first or second piston;
• said reflector means being mounted within the associated said first or second cylinder, and including a first reflector mounted on the side wall of the associated said first or second cylinder opposite said ultrasonic transducer, for reflecting transmitted signals from said first signal path to a second signal path parallel to the longitudinal axis of said associated piston, and a second reflector on the face of said associated piston for reflecting the signals back along said second signal path to said first reflector as said first and second displacement signals, the first reflector serving to reflect the first and second displacement signals along said first signal path back to said first ultrasonic transducer, for detection by the latter;
• and
• control means for controlling the operation of said first ultrasonic detection means, said control means including calculating means for receiving said first and second displacement signals for calculating therefrom and indicating the total volume displaced by at least said first and second pistons during a given dispensing cycle or operation.

In a rotary positive displacement piston meter for metering or measuring the volume of fluid dispensed from a dispensing system, said rotary positive displacement piston meter includes first and second pistons mounted within first and second opposing cylinders, respectively, and third and fourth pistons mounted within third and fourth opposing cylinders, respectively, said first and second pistons reciprocating in opposition to one another within their respective cylinders, and said third and fourth pistons reciprocating in opposition to one another within their respective cylinders, each one of said first through fourth pistons move in a downstroke when fluid under external pressure is forced into their respective cylinder, and move in an upstroke to force fluid out of their respective cylinder for dispensing, the total volume displaced by the pistons within respective cylinders during a given dispensing cycle being equivalent to the total volume of fluid dispensed, wherein the improvement comprises:

• first and second ultrasonic detection means mounted within said first and third cylinders for periodically providing first and second position signals indicative of the positions of said first and second pistons, and said third and fourth pistons, respectively, at various times as said pistons reciprocate within their associated said first through fourth cylinders, respectively, over a given measuring period for dispensing fluid, said first and second ultrasonic detection means including first and second ultrasonic transducer means, respectively, for both transmitting ultrasonic pulses into said first and third cylinders, respectively, and for receiving said first and second position signals reflected back from said first and third pistons, respectively, and first and second reflector means for establishing signal paths between said first ultrasonic transducer means and said first piston, and between said second ultrasonic transducer means and said third piston, respectively;
• said first and second ultrasonic transducer means including first and second ultrasonic transducers, respectively, mounted in outermost side portions of said first and third cylinders, respectively, for transmitting and receiving acoustic signals along a first signal path transverse to the longitudinal axes of said first and third pistons, respectively;
• said first and second reflector means being mounted within said first and third cylinders, respectively, and each of said first and second reflector means including a first reflector mounted on the side wall of said first and third cylinders, respectively, opposite said first and second ultrasonic transducers, respectively, for reflecting transmitted signals from said first signal path to a second signal path parallel to the longitudinal axes of said first and third pistons, respectively, and a second reflector on the face of each of said first and third pistons, respectively, for reflecting the associated signals back along said second signal paths to said first reflectors, respectively, as said first position signals, the first reflectors serving to reflect the first position signals along said first signal paths back to said first and second ultrasonic transducers, respectively, for detection by the latter two;
• and
• control means for controlling the operation of said first and second ultrasonic detection means, said control means including calculating means for receiving said first and second position signals for calculating and indicating the total volume displaced by said first through fourth pistons during the measuring or dispensing period.