Viscometer

• US 4,750,359 A
• Filed: 08/24/1981
• Issued: 06/14/1988
• Est. Priority Date: 06/29/1979
• Status: Expired due to Fees

• Current Assignee: Phillips Petroleum Company (ConocoPhillips)
• Original Assignee: Phillips Petroleum Company (ConocoPhillips)
• Inventors: Johnson, Timothy W., O'Shaughnessy, Marion T.
• Primary Examiner(s): Levy, Stewart J.
• Assistant Examiner(s): Roskos, Joseph W.
• Application Number:
  US06/295,460
• Time in Patent Office: 2,486 Days
• Field of Search: 73/304 C, 331/116 FE, 331/65, 324/133, 324/336, 324/442, 368/113
• US Class Current: 73/304.00C
• CPC Class Codes: G01N 11/06 by timing the outflow of a known quantity

Abstract

A capillary tube viscometer is provided in which the viscosity of a fluid can be measured at a temperature above the normal boiling point of at least one component in the fluid. The fluid is heated to the desired temperature in a sealed viscometer which is constructed so as to withstand high pressure. The fluid is then allowed to flow through a capillary tube and the time required for the fluid to flow through the capillary tube is measured. The viscosity of the fluid is then calculated based on the Hagen-Poiseuille law.

Claims

1. A method for measuring the elapsed time between the time a fluid contacts a first capacitive sensor and the time said fluid contacts a second capacitive sensor comprising the steps of;

triggering a first field-effect transistor oscillator when said fluid contacts said first capacitive sensor to thereby start a timing device; and

triggering a second field-effect transistor oscillator when said fluid contacts said second capacitive sensor to thereby stop said timing device, the time indicated by said timing device providing a measurement of the elapsed time between the time said fluid contacts said first capacitive sensor and the time said fluid contacts said second capacitive sensor.

2. Apparatus comprising:

a first capacitive sensor;

a second capacitive sensor;

a first field-effect transistor oscillator, said first capacitive sensor forming a capacitive element which is an integral portion of said first field-effect transistor oscillator, the values of the elements which make up said first field-effect transistor oscillator being chosen in such a manner that said first field-effect transistor oscillator will oscillate only when fluid covers said first capacitive sensor;

a second field-effect transistor oscillator, said second capacitive sensor forming a capacitive element which is an integral portion of said second field-effect transistor oscillator, the values of the elements which make up said second field-effect transistor oscillator being chosen in such a manner that said second field-effect transistor oscillator will oscillate only when fluid covers said second capacitive sensor;

a timing means;

means for supplying the oscillating output of said first field-effect transistor oscillator to said timing means; and

means for supplying the oscillating output of said second field-effect transistor oscillator to said timing means, said timing means being initiated by the oscillating output of said first field-effect transistor oscillator and being stopped by the oscillating output of said second field-effect transistor oscillator, the time indicated by said timing means providing a measurement of the elapsed time between the time fluid contacts said first capacitive sensor and the time fluid contacts said second capacitive sensor.

3. Apparatus in accordance with claim 2 wherein said first field-effect transistor oscillator and said second field-effect transistor oscillator each comprises:

a field-effect transistor having a gate, source and drain;

a crystal having first and second terminals;

a power supply;

a first inductor;

means for electrically connecting the drain of said field-effect transistor through said first inductor to said power supply;

means for electrically connecting the drain of said field-effect transistor to the second terminal of said crystal;

a first capacitor;

means for electrically connecting said first capacitive sensor through said first capacitor to the second terminal of said crystal;

a second capacitor;

a second inductor;

means for electrically connecting said second capacitor in parallel with the capacitance formed by either said first capacitive sensor or said second capacitive sensor;

means for electrically connecting said second inductor in parallel with the capacitor formed by either said first capacitive sensor or said second capacitive sensor;

means for electrically connecting the parallel combination of said second capacitor, said second inductor, and said first or second capacitive sensor to ground;

means for electrically connecting the source of said field-effect transistor through said first resistor to ground;

a second resistor;

means for electrically connecting the first terminal of said crystal to ground through said second resistor;

means for electrically connecting the gate of said field-effect transistor to the first terminal of said crystal; and

means for electrically connecting the gate of said field-effect transistor through said second resistor to ground, the values of said first and second capacitors and said second inductor being chosen in such a manner that said first or second field-effect transistor oscillator oscillates only when fluid covers said first or second capacitive sensor, respectively.

4. Apparatus comprising:

a capacitive sensor; and

a field-effect transistor oscillator, said capacitive sensor forming a capacitive element which is an integral portion of said field-effect transistor oscillator, the values of the elements which make up said field-effect transistor oscillator being chosen in such a manner that said field-effect transistor oscillator will oscillate only when fluid contacts said capacitive sensor, the oscillations of said field-effect transistor oscillator providing an indication of when fluid is in contact with said capacitive sensor.

5. Apparatus in accordance with claim 4 wherein said field-effect transistor oscillator comprises:

a field-effect transistor having a gate, source and drain;

a crystal having first and second terminals;

a power supply;

a first inductor;

means for electrically connecting the drain of said field-effect transistor through said first inductor to said power supply;

means for electrically connecting the drain of said field-effect transistor to the second terminal of said crystal;

a first capacitor;

means for electrically connecting said capacitive sensor through said first capacitor to the second terminal of said crystal;

a second capacitor;

a second inductor;

means for electrically connecting said second capacitor in parallel with said capacitive sensor;

means for electrically connecting said second inductor in parallel with said capacitive sensor;

means for electrically connecting the parallel combination of said second capacitor, said second inductor, and said capacitive sensor to ground;

means for electrically connecting the source of said field-effect transistor through said first resistor to ground;

a second resistor;

means for electrically connecting the first terminal of said crystal to ground through said second resistor;

means for electrically connecting the gate of said field-effect transistor to the first terminal of said crystal oscillator; and

means for electrically connecting the gate of said field-effect transistor through said second resistor to ground, the values of said first and second capacitors and said second inductor being chosen in such a manner that said field-effect transistor oscillator oscillates only when fluid contacts said capacitive sensor.