Method and apparatus for measuring viscosity

• US 5,696,315 A
• Filed: 10/03/1996
• Issued: 12/09/1997
• Est. Priority Date: 10/18/1995
• Status: Expired due to Term

• Current Assignee: Cannon Instrument Company (Arthur H. Thomas Co., Inc.)
• Original Assignee: Cannon Instrument Company (Arthur H. Thomas Co., Inc.)
• Inventors: Ball, Dean M.
• Primary Examiner(s): BROCK, MICHAEL J
• Application Number:
  US08/724,860
• Time in Patent Office: 432 Days
• Field of Search: 73/54.01, 73/54.04, 73/54.07, 73/54.43, 73/864.21, 73/864.23, 73/864.24, 73/864.73, 73/864.74, 73/864.81
• US Class Current: 73/54.43
• CPC Class Codes: B01L 7/02 Water baths; Sand baths; Air baths
• CPC Class Codes: G01N 11/04 through a restricted passage, e.g. tube, aperture
• CPC Class Codes: G01N 2011/0006 Calibrating, controlling or cleaning viscometers

Abstract

An apparatus for measuring viscosity of liquids includes an external chamber (10) which encloses an internal chamber/duct (20) having an inlet (21) and an outlet (22). Internal chamber (20) houses a fan (30) for forcing air through the duct, a first heater (40) for heating air within the duct, a second heater (81/82) for heating air externally of the duct, a thermal ballast (50) for maintaining the temperature of the air in the duct constant, and a viscometer (72) for measuring viscosity of liquids.

Claims

1. Apparatus for measuring the viscosity of liquids in an ultra stable temperature environment which comprises a thermally insulated test chamber, support means for supporting containers of liquids to be tested within said chamber, a thermally insulated duct mounted within said chamber, means for circulating air within said chamber through said duct, first heater means mounted within said duct for heating air flowing through said duct, second heater means mounted outside said duct for heating air circulating externally of said duct, and viscometer means mounted at least partially within said duct downstream of said heater means for measuring the viscosity of liquids in containers supported upon said support means.

2. The apparatus of claim 1 wherein said test chamber has a top wall, a bottom wall and side walls and wherein said second heating means is embedded within at least one of said walls.

3. The apparatus of claim 2 wherein said second heating means has a heating element embedded within said chamber top wall.

4. The apparatus of claim 2 wherein said second heating means has a heating element embedded within said chamber bottom wall.

5. The apparatus of claim 4 wherein said second heating means has a heating element within a said chamber top wall.

6. The apparatus of claim 2 wherein said chamber walls have a metallic inner shell and a thermally insulative outer shell and wherein said second heater means has a heating element mounted between said inner shell and said outer shell.

7. The apparatus of claim 1 wherein said duct has an inlet and an outlet, and wherein said air circulating means comprises a fan mounted adjacent said duct inlet.

8. The apparatus of claim 7 wherein said support means is mounted within said chamber adjacent said duct outlet.

9. The apparatus of claim 8 wherein said support means comprises a tray mounted below said duct outlet.

10. The apparatus of claim 9 wherein said support means further comprises means for repositioning said tray along a substantially horizontal plane located below said duct outlet.

11. The apparatus of claim 9 further comprising means for raising and lowering said viscometer means.

12. The apparatus of claim 1 further comprising thermal ballasting means mounted in said duct between said first heater means and said viscometer means.

13. The apparatus of claim 12 wherein said thermal ballasting means comprises a plurality of mutually spaced metallic plates.

14. A method of measuring the viscosity of a liquid in a container which comprises the steps of:

(a) placing the container in a thermally insulated chamber housing a duct and a viscometer mounted at least partially within the duct,

(b) circulating air within the chamber through the duct over the viscometer, about the outside of the duct and back into the duct,

(c) heating the air flowing internally within the duct with a first heater,

(d) heating the air flowing externally of the duct within the chamber prior to re-entry of the air into the duct with a second heater, and

(e) inserting the viscometer into the container and liquid.