APPARATUS FOR MEASURING MASS FLOW OF FLUIDBORNE SOLIDS

• US 3,635,082 A
• Filed: 04/23/1969
• Issued: 01/18/1972
• Est. Priority Date: 04/23/1969
• Status: Expired due to Term

• Current Assignee: Joseph Pysnik, Samuel B. Prellwitz
• Original Assignee: Joseph Pysnik, Samuel B. Prellwitz
• Inventors: Prellwitz, Samuel B., Pysnik, Joseph
• Primary Examiner(s): Queisser, Richard C.
• Assistant Examiner(s): Smellar, Marvin
• Application Number:
  US04/818,527
• Time in Patent Office: 1,000 Days
• Field of Search: 324/61,65 235/151.34 73/194,28,32,434,61R,432PS
• US Class Current: 73/861.04
• CPC Class Codes: G01F 1/712 using auto-correlation or cross-correlation detection means
• CPC Class Codes: G01F 1/74 Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid

Abstract

Finely divided particles in a fluid stream transported in a conduit comprise the dielectric of two spaced-apart capacitors at electrically insulated inserts in the conduit. Circuitry determines the time span between correlated variations in capacitance of the two capacitors as a measure of stream velocity. Additional circuitry determines stream density by measuring the capacitance. The velocity and density circuit outputs are multiplied to provide a mass flow rate. An integrator provides total flow.

Claims

1. Apparatus for measuring the flow of finely divided particles transported in varying density through a conduit in a fluid stream comprising a first detector at a first location on the conduit for detecting variations in particle density, a second detector at a second location on the conduit spaced apart and downstream from the first detector for detecting variations in particle density, means connected to the detectors and responsive to variations in particle density for measuring particle velocity by determining the time delay between the detection of correlated variations in particle density at the first detector and at the second detector, means for measuring particle density in the conduit, and means combining said velocity-measuring means and said density-measuring means for indicating mass flow rate of particles in said conduit.

2. Apparatus according to claim 1 in which said first detector includes a first capacitor with plates arranged on the outside of the conduit so that the amount of particles in the conduit effects the dielectric constant of the capacitor, a first capacitance transducer connected to said capacitor for providing a first electrical output proportional to the capacitance of the first capacitor, a first coupling capacitor connected to the first transducer for passing only variations in the first electrical output, and said second detector includes a second capacitor with plates arranged on the outside of the conduit so that the amount of particles in the conduit effects the dielectric constant at the capacitor, said second capacitor having the same characteristics as the first capacitor, a second capacitance transducer connected to said second capacitor for providing a second electrical output proportional to the capacitance of the second capacitor, said second capacitance transducer having the same characteristics as said first capacitance transducer, and a second coupling capacitor connected to the second transducer for passing only variations in the second electrical output.

3. Apparatus according to claim 1 in which the means for measuring particle density in the conduit is a nuclear density gage.

4. Apparatus according to claim 1 which includes means for periodically injecting increments of fluid into the conduit upstream from the first detector thereby providing turbulence in the fluid flow and assuring variations in particle mass flow.

5. Apparatus according to claim 2 in which the means for measuring the particle velocity includes a first comparator connected to the first coupling capacitor, thereby enabling the comparator to compare variations in the first electrical output with a predetermined level and to change state whenever the level of the variations in the first electrical output changes from one side of the predetermined level to the other side of the predetermined level, a second comparator connected to the second coupling capacitor and having the same characteristics as the first comparator, means for converting the time delay between correlated changes in the output states of the comparators to a voltage thereby providing a measure of average particle velocity between detectors, and a first voltmeter connected to the output of the converting means.

6. Apparatus according to claim 5 in which the means for combining said velocity-measuring means and said density-measuring means for indicating mass flow rate includes an amplifier connected to the first transducer, a multiplier connected to the amplifier output and the output of the converting means for multiplying the output of the amplifier by the output of the converting means thereby providing a voltage proportional to the rate of mass flow of the particles, And means for indicating the mass flow rate connected to the multiplier output.

7. Apparatus according to claim 6 including an integrator connected to the output of the multiplier, and means connected to the output of the integrator for indicating total mass flow.

8. Apparatus according to claim 6 in which the conduit is a round tube composed of electrical insulating material at the detector locations, and the plates of the first and second capacitor are each in the shape of narrow spaced-apart parallel ribbons disposed in a spiral configuration around the conduit with the flat side of each ribbon next to the outside of the conduit.